全文获取类型
收费全文 | 1181篇 |
免费 | 100篇 |
国内免费 | 2篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 31篇 |
2020年 | 15篇 |
2019年 | 14篇 |
2018年 | 42篇 |
2017年 | 23篇 |
2016年 | 40篇 |
2015年 | 75篇 |
2014年 | 62篇 |
2013年 | 82篇 |
2012年 | 97篇 |
2011年 | 94篇 |
2010年 | 69篇 |
2009年 | 37篇 |
2008年 | 69篇 |
2007年 | 75篇 |
2006年 | 57篇 |
2005年 | 51篇 |
2004年 | 43篇 |
2003年 | 47篇 |
2002年 | 34篇 |
2001年 | 31篇 |
2000年 | 19篇 |
1999年 | 9篇 |
1998年 | 13篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 9篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 9篇 |
1991年 | 14篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 6篇 |
1971年 | 5篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1968年 | 4篇 |
1966年 | 3篇 |
排序方式: 共有1283条查询结果,搜索用时 312 毫秒
81.
The gastrointestinal tract constitutes a physiological interface integrating nutrient and microbiota-host metabolism. Conjugated linoleic acids (CLA) have been reported to contribute to decreased body weight and fat accretion. The modulation by dietary CLA of stomach proteins related to energy homeostasis or microbiota may be involved, although this has not been previously analysed. This is examined in the present study, which aims to underline the potential mechanisms of CLA which contribute to body weight regulation. Adult mice were fed either a normal fat (NF, 12% kJ content as fat) or a high-fat (HF, 43% kJ content as fat) diet. In the latter case, half of the animals received daily oral supplementation of CLA. Expression and content of stomach proteins and specific bacterial populations from caecum were analysed. CLA supplementation was associated with an increase in stomach protein expression, and exerted a prebiotic action on both Bacteroidetes/Prevotella and Akkermansia muciniphila. However, CLA supplementation was not able to override the negative effects of HF diet on Bifidobacterium spp., which was decreased in both HF and HF+CLA groups. Our data show that CLA are able to modulate stomach protein expression and exert a prebiotic effect on specific gut bacterial species. 相似文献
82.
Luz-María Torres Liliana Rivera-Espinosa Juan L. Chávez-Pacheco Carlos F. Navas Joel A. Demetrio Radamés Alemón-Medina Francisca Trujillo Martín Pérez Martha M. Zapata Rocío Cárdenas Citlaltepetl Salinas Arnoldo Aquino Rafael Velázquez-Cruz Manuel-de-Jesús Castillejos 《PloS one》2015,10(11)
Ifosfamide blood concentrations are necessary to monitor its therapeutic response, avoiding any adverse effect. We developed and validated an analytical method by UPLC-MS/MS to quantify ifosfamide in dried blood spots (DBS). Blood samples were collected on Whatman 903® filter paper cards. Five 3 mm disks were punched out from each dried blood spot. Acetonitrile and ethyl acetate were used for drug extraction. Chromatographic separation was carried out in an Acquity UPLC equipment with a BEH-C18 column, 2.1 x 100 mm, 1.7 μm (Waters®). The mobile phase consisted in 5 mM ammonium formate and methanol:acetonitrile (40:48:12 v/v/v) at 0.2 mL/min. LC-MS/MS detection was done by ESI+ and multiple reaction mode monitoring, ionic transitions were m/z1+ 260.99 > 91.63 for ifosfamide and 261.00 > 139.90 for cyclophosphamide (internal standard). This method was linear within a 100–10000 ng/mL range and it was accurate, precise and selective. Ifosfamide samples in DBS were stable for up to 52 days at -80°C. The procedure was tested in 14 patients, ages 1 month to 17 years (9 males and 5 females), with embryonic tumours treated with ifosfamide, alone or combined, at a public tertiary referral hospital. Ifosfamide blood levels ranged from 11.1 to 39.7 μmol/L at 12 hours after the last infusion, while 24-hour levels ranged from 0.7–19.7 μmol/L. The median at 12 hours was 19.5 μmol/L (Q25 14.4–Q75 29.0) and 3.8 μmol/L (Q25 1.5–Q75 9.9) at 24 hours, p<0.001. This method is feasible to determine ifosfamide plasma levels in paediatric patients. 相似文献
83.
Sílvia Saumell Francesc Solé Leonor Arenillas Julia Montoro David Valcárcel Carme Pedro Carmen Sanzo Elisa Lu?o Teresa Giménez Montserrat Arnan Helena Pomares Raquel De Paz Beatriz Arrizabalaga Andrés Jerez Ana B. Martínez Judith Sánchez-Castro Juan D. Rodríguez-Gambarte José M. Raya Eduardo Ríos María Rodríguez-Rivera Blanca Espinet Lourdes Florensa 《PloS one》2015,10(6)
Isolated trisomy 8 is not considered presumptive evidence of myelodysplastic syndrome (MDS) in cases without minimal morphological criteria. One reason given is that trisomy 8 (+8) can be found as a constitutional mosaicism (cT8M). We tried to clarify the incidence of cT8M in myeloid neoplasms, specifically in MDS, and the diagnostic value of isolated +8 in MDS. Twenty-two MDS and 10 other myeloid neoplasms carrying +8 were studied. Trisomy 8 was determined in peripheral blood by conventional cytogenetics (CC) and on granulocytes, CD3+ lymphocytes and oral mucosa cells by fluorescence in situ hybridization (FISH). In peripheral blood CC, +8 was seen in 4/32 patients. By FISH, only one patient with chronic myelomonocytic leukemia showed +8 in all cell samples and was interpreted as a cT8M. In our series +8 was acquired in all MDS. Probably, once discarded cT8M by FISH from CD3+ lymphocytes and non-hematological cells, +8 should be considered with enough evidence to MDS. 相似文献
84.
Adriano José Pereira Thiago Domingos Corrêa Francisca Pereira de Almeida Rodrigo Octávio Deliberato Michelle dos Santos Lobato Nelson Akamine Eliézer Silva Alexandre Biasi Cavalcanti 《PloS one》2015,10(6)
Introduction
Current guidelines and consensus recommend arterial and venous samples as equally acceptable for blood glucose assessment in point-of-care devices, but there is limited evidence to support this recommendation. We evaluated the accuracy of two devices for bedside point-of-care blood glucose measurements using arterial, fingerstick and catheter venous blood samples in ICU patients, and assessed which factors could impair their accuracy.Methods
145 patients from a 41-bed adult mixed-ICU, in a tertiary care hospital were prospectively enrolled. Fingerstick, central venous (catheter) and arterial blood (indwelling catheter) samples were simultaneously collected, once per patient. Arterial measurements obtained with Precision PCx, and arterial, fingerstick and venous measurements obtained with Accu-chek Advantage II were compared to arterial central lab measurements. Agreement between point-of-care and laboratory measurements were evaluated with Bland-Altman, and multiple linear regression models were used to investigate interference of associated factors.Results
Mean difference between Accu-chek arterial samples versus central lab was 10.7 mg/dL (95% LA -21.3 to 42.7 mg/dL), and between Precision PCx versus central lab was 18.6 mg/dL (95% LA -12.6 to 49.5 mg/dL). Accu-chek fingerstick versus central lab arterial samples presented a similar bias (10.0 mg/dL) but a wider 95% LA (-31.8 to 51.8 mg/dL). Agreement between venous samples with arterial central lab was the poorest (mean bias 15.1 mg/dL; 95% LA -51.7 to 81.9). Hyperglycemia, low hematocrit, and acidosis were associated with larger differences between arterial and venous blood measurements with the two glucometers and central lab. Vasopressor administration was associated with increased error for fingerstick measurements.Conclusions
Sampling from central venous catheters should not be used for glycemic control in ICU patients. In addition, reliability of the two evaluated glucometers was insufficient. Error with Accu-chek Advantage II increases mostly with central venous samples. Hyperglycemia, lower hematocrit, acidosis, and vasopressor administration increase measurement error. 相似文献85.
Francisca Mutapi Lorraine Pfavayi Derick Osakunor Rivka Lim Maritha Kasambala Arnold Mutemeri Simbarashe Rusakaniko Dixon Chibanda Takafira Mduluza 《PLoS neglected tropical diseases》2021,15(8)
There is a paucity of reference early childhood development (ECD) data at community level in rural Africa. Our objective was to conduct a comprehensive assessment of ECD in rural Zimbabwe and determine the impact of stunting and schistosome infections on ECD. Using the Griffiths Scales of Child Development, we conducted a cross sectional assessment of Eye and Hand Coordination (EHC), Personal-Social-Emotional (PSE), Language and Communication (LC), Foundations of Learning (FL) and Gross Motor (GM) domains and the summary General Development (GD) in 166 children aged 6–72 months. The effects of stunting, malnutrition and Schistosoma haematobium infection on ECD was determined. The impact of praziquantel curative treatment of schistosome infection on the developmental scores was determined through a longitudinal follow up at 6 and 12 months. From an initial 166 children, 11 were found to have developmental deficits warranting further investigation. Of the remaining 155, 58.7% recorded a good (≥ average) score for the overall General Development (GD). Proportions of children scoring above the cut-off (≥ average) for each domain were GM (84.5%), PSE (80.6%), EHC (61.9%), FL (43.9%) and LC (44.5%). The prevalence of stunting was 26.8% (95% CI = 20.1%–34.8%) Scores for stunted children were significantly lower for EHC (p = 0.0042), GM (p = 0.0099), and GD (p = 0.0014) with the fraction of lower scores attributable to stunting being GM = 63.4%, GD = 46.6%, EHC = 45%, and LC = 21%. S. haematobium infection prevalence was 39.7% and mean infection intensity was 5.4 eggs/10 ml urine. Infected children had poorer cognitive performance scores for the FL (p = 0.0005) with 30.8% of poor FL attributable to the infection. Performance in all domains improved to the expected normal or above reference levels at 6 and 12 months post curative treatment of schistosome infections. Our study documented reference values for ECD in rural Zimbabwean children. The study detected deficiencies in the FL domain, which were more pronounced in children, infected with schistosomes, highlighting the need for provision of cognitive stimulation tools and access to early childhood foundation education. There is also need for improved child nutrition and treatment of schistosome infections to improve child development outcomes. 相似文献
86.
Melchor Juan J. Jesús Casas M. Antonia Elorrieta Santiago Bonachela Irene Gallego Francisca Fuentes-Rodríguez Encarnación Fenoy 《Hydrobiologia》2014,732(1):183-196
Irrigation ponds may act as a source of phytopathogenic species that might infest crops through the irrigation systems. Many studies have shown that submerged macrophytes can improve water clarity by out-competing phytoplankton by means of various mechanisms: favoured phytoplankton-grazing zooplankton, reduced nutrient and light availability, increased sinking losses and the release of allelopathically active substances. However, less information is available on the effects of submerged macrophytes on heterotrophic aquatic organisms such as pathogenic bacteria, fungi or oomycete species. This paper studies the effects of three submerged macrophytes—Chara fragilis, Potamogeton pectinatus and Najas marina—on the viability in water of propagules of two phytopathogenic isolates of the oomycetes Pythium aphanidermatum and Pythium ultimum. Moreover, we tested general antimicrobial properties (against bacteria and fungi in water) for these macrophytes. The results showed clear inhibitory effects of all three macrophytes on bacterial density in water and of C. fragilis on the viability of Pythium. Thus, preserving aquatic vegetation in irrigation ponds (i.e. charophytes), besides its purely environmental interest, may have important agronomic benefits owing to their role as biological control against some phytopathogenic agents. 相似文献
87.
María Isabel Burgos Alves Francisco Avilés Plaza Rebeca Martínez-Tomás María Sánchez-Campillo Elvira Larqué Francisca Pérez-Llamas Pedro Martínez Hernández Soledad Parra Pallarés 《Journal of physiology and biochemistry》2010,66(3):221-227
The biological effects of oxidized LDL (oxLDL) may contribute to initiation and progression of the atherosclerotic process,
and the association between cardiovascular disease and oxidation of LDL has been largely demonstrated. The objectives of this
study were to establish the reference values of oxidative stress biomarkers in a young healthy Spanish population to determine
the concentration of oxLDL and its relationship with lipid profile and with these biomarkers. oxLDL, F2-isoprostanes, protein carbonyls (PC), and 8-hydroxy-2′-deoxyguanosine (8-OHdG) were determinate by ELISA in 72 healthy subjects.
Antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) were carried
out on a Hitachi 912 analyzer; lipid profile were assayed using automated systems (Cobas 711, Roche Diagnostics). All statistics
were analyzed by using SPSS for Windows 15.0. SPSS Inc, Chicago, IL, USA. (Normal mean reference values): oxLDL (63.23 ± 16.23
U/L), (Male/Female 68.06 ± 17.69/58.39 ± 13.6 U/L), F2-isoprostanes (2.26 ± 0.9 μg/g creatinine), PC (0.34 ± 0.15 nmol/mg), 8-OHdG (23.27 ± 10.58 ng/ml), SOD (931.97 ± 271.09 U/g
Hb), GR (46.56 ± 11.68 U/L), GPx (27.58 ± 6.89 U/gHb (Male/Female 25.91 ± 5.03/29.2 ± 8.07 U/L)). OxLDL (63.23 U/L) was significantly
(p < 0.05) positively correlated with BMI (22.53 Kg/m2), total cholesterol (175.79 mg/dl), triglycerides (87.58 mg/dl), LDL cholesterol (96.25 mg/dl), and uric acid (4.78 mg/dl),
while negatively correlated with HDL-cholesterol (62.25 mg/dl). We have found different correlation between oxLDL and isoprostanes
by gender with the rest of parameters. Normal reference values have been found significantly different for oxLDL and GPx by
gender. Oxidized LDL is correlated with lipid profile but not with the oxidative stress biomarkers. Urinary isoprostanes are
positively correlated with triglycerides and negatively with GR and GPx. 相似文献
88.
Esther Melgarejo Miguel Ángel Medina Francisca Sánchez-Jiménez José Luis Urdiales 《Journal of physiology and biochemistry》2010,66(3):265-270
The human body is made of some 250 different cell types. From them, only a small subset of cell types is able to produce histamine.
They include some neurons, enterochromaffin-like cells, gastrin-containing cells, mast cells, basophils, and monocytes/macrophages,
among others. In spite of the reduced number of these histamine-producing cell types, they are involved in very different
physiological processes. Their deregulation is related with many highly prevalent, as well as emergent and rare diseases,
mainly those described as inflammation-dependent pathologies, including mastocytosis, basophilic leukemia, gastric ulcer,
Crohn disease, and other inflammatory bowel diseases. Furthermore, oncogenic transformation switches some non-histamine-producing
cells to a histamine producing phenotype. This is the case of melanoma, small cell lung carcinoma, and several types of neuroendocrine
tumors. The bioactive compound epigallocatechin-3-gallate (EGCG), a major component of green tea, has been shown to target
histamine-producing cells producing great alterations in their behavior, with relevant effects on their proliferative potential,
as well as their adhesion, migration, and invasion potentials. In fact, EGCG has been shown to have potent anti-inflammatory,
anti-tumoral, and anti-angiogenic effects and to be a potent inhibitor of the histamine-producing enzyme, histidine decarboxylase.
Herein, we review the many specific effects of EGCG on concrete molecular targets of histamine-producing cells and discuss
the relevance of these data to support the potential therapeutic interest of this compound to treat inflammation-dependent
diseases. 相似文献
89.
Francisca Reyes Gabriel León Maribel Donoso Federica Brandizzí Andreas P.M. Weber Ariel Orellana 《The Plant journal : for cell and molecular biology》2010,61(3):423-435
Uridine 5′‐diphosphate (UDP)‐glucose is transported into the lumen of the endoplasmic reticulum (ER), and the Arabidopsis nucleotide sugar transporter AtUTr1 has been proposed to play a role in this process; however, different lines of evidence suggest that another transporter(s) may also be involved. Here we show that AtUTr3 is involved in the transport of UDP‐glucose and is located at the ER but also at the Golgi. Insertional mutants in AtUTr3 showed no obvious phenotype. Biochemical analysis in both AtUTr1 and AtUTr3 mutants indicates that uptake of UDP‐glucose into the ER is mostly driven by these two transporters. Interestingly, the expression of AtUTr3 is induced by stimuli that trigger the unfolded protein response (UPR), a phenomenon also observed for AtUTr1, suggesting that both AtUTr1 and AtUTr3 are involved in supplying UDP‐glucose into the ER lumen when misfolded proteins are accumulated. Disruption of both AtUTr1 and AtUTr3 causes lethality. Genetic analysis showed that the atutr1 atutr3 combination was not transmitted by pollen and was poorly transmitted by the ovules. Cell biology analysis indicates that knocking out both genes leads to abnormalities in both male and female germ line development. These results show that the nucleotide sugar transporters AtUTr1 and AtUTr3 are required for the incorporation of UDP‐glucose into the ER, are essential for pollen development and are needed for embryo sac progress in Arabidopsis thaliana. 相似文献
90.
Tobias Manigold Andrés Mori Rebecca Graumann Elena Llop Valeska Simon Marcela Ferrés Francisca Valdivieso Constanza Castillo Brian Hjelle Pablo Vial 《PLoS pathogens》2010,6(2)
In man, infection with South American Andes virus (ANDV) causes hantavirus cardiopulmonary syndrome (HCPS). HCPS due to ANDV is endemic in Southern Chile and much of Argentina and increasing numbers of cases are reported all over South America. A case-fatality rate of about 36% together with the absence of successful antiviral therapies urge the development of a vaccine. Although T-cell responses were shown to be critically involved in immunity to hantaviruses in mouse models, no data are available on the magnitude, specificity and longevity of ANDV-specific memory T-cell responses in patients. Using sets of overlapping peptides in IFN-γ ELISPOT assays, we herein show in 78 Chilean convalescent patients that Gn-derived epitopes were immunodominant as compared to those from the N- and Gc-proteins. Furthermore, while the relative contribution of the N-specific response significantly declined over time, Gn-specific responses remained readily detectable ex vivo up to 13 years after the acute infection. Tetramer analysis further showed that up to 16.8% of all circulating CD3+CD8+ T cells were specific for the single HLA-B*3501-restricted epitope Gn465–473 years after the acute infection. Remarkably, Gn465–473–specific cells readily secreted IFN-γ, granzyme B and TNF-α but not IL-2 upon stimulation and showed a ‘revertant’ CD45RA+CD27−CD28−CCR7−CD127− effector memory phenotype, thereby resembling a phenotype seen in other latent virus infections. Most intriguingly, titers of neutralizing antibodies increased over time in 10/17 individuals months to years after the acute infection and independently of whether they were residents of endemic areas or not. Thus, our data suggest intrinsic, latent antigenic stimulation of Gn-specific T-cells. However, it remains a major task for future studies to proof this hypothesis by determination of viral antigen in convalescent patients. Furthermore, it remains to be seen whether Gn-specific T cells are critical for viral control and protective immunity. If so, Gn-derived immunodominant epitopes could be of high value for future ANDV vaccines. 相似文献