全文获取类型
收费全文 | 1213篇 |
免费 | 76篇 |
出版年
2024年 | 1篇 |
2023年 | 14篇 |
2022年 | 26篇 |
2021年 | 40篇 |
2020年 | 37篇 |
2019年 | 34篇 |
2018年 | 40篇 |
2017年 | 31篇 |
2016年 | 52篇 |
2015年 | 83篇 |
2014年 | 77篇 |
2013年 | 102篇 |
2012年 | 125篇 |
2011年 | 103篇 |
2010年 | 48篇 |
2009年 | 46篇 |
2008年 | 76篇 |
2007年 | 63篇 |
2006年 | 46篇 |
2005年 | 41篇 |
2004年 | 34篇 |
2003年 | 33篇 |
2002年 | 22篇 |
2001年 | 19篇 |
2000年 | 9篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 8篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 7篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1978年 | 1篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1967年 | 2篇 |
排序方式: 共有1289条查询结果,搜索用时 15 毫秒
901.
Paula Giselle Czaikoski José Maurício Segundo Correia Mota Daniele Carvalho Nascimento Fabiane S?nego Fernanda Vargas e Silva Castanheira Paulo Henrique Melo Gabriela Trentin Scortegagna Rangel Leal Silva Romualdo Barroso-Sousa Fabrício Oliveira Souto Antonio Pazin-Filho Florencio Figueiredo José Carlos Alves-Filho Fernando Queiróz Cunha 《PloS one》2016,11(2)
Organ dysfunction is a major concern in sepsis pathophysiology and contributes to its high mortality rate. Neutrophil extracellular traps (NETs) have been implicated in endothelial damage and take part in the pathogenesis of organ dysfunction in several conditions. NETs also have an important role in counteracting invading microorganisms during infection. The aim of this study was to evaluate systemic NETs formation, their participation in host bacterial clearance and their contribution to organ dysfunction in sepsis. C57Bl/6 mice were subjected to endotoxic shock or a polymicrobial sepsis model induced by cecal ligation and puncture (CLP). The involvement of cf-DNA/NETs in the physiopathology of sepsis was evaluated through NETs degradation by rhDNase. This treatment was also associated with a broad-spectrum antibiotic treatment (ertapenem) in mice after CLP. CLP or endotoxin administration induced a significant increase in the serum concentrations of NETs. The increase in CLP-induced NETs was sustained over a period of 3 to 24 h after surgery in mice and was not inhibited by the antibiotic treatment. Systemic rhDNase treatment reduced serum NETs and increased the bacterial load in non-antibiotic-treated septic mice. rhDNase plus antibiotics attenuated sepsis-induced organ damage and improved the survival rate. The correlation between the presence of NETs in peripheral blood and organ dysfunction was evaluated in 31 septic patients. Higher cf-DNA concentrations were detected in septic patients in comparison with healthy controls, and levels were correlated with sepsis severity and organ dysfunction. In conclusion, cf-DNA/NETs are formed during sepsis and are associated with sepsis severity. In the experimental setting, the degradation of NETs by rhDNase attenuates organ damage only when combined with antibiotics, confirming that NETs take part in sepsis pathogenesis. Altogether, our results suggest that NETs are important for host bacterial control and are relevant actors in the pathogenesis of sepsis. 相似文献
902.
Luana Amorim Biondo Edson Alves Lima Junior Camila Oliveira Souza Maysa Mariana Cruz Roberta D. C. Cunha Maria Isabel Alonso-Vale Lila Missae Oyama Claudia M. Oller Nascimento Gustavo Duarte Pimentel Ronaldo V. T. dos Santos Fabio Santos Lira José Cesar Rosa Neto 《PloS one》2016,11(3)
White adipose tissue (WAT) plays a fundamental role in maintaining energy balance and important endocrine functions. The loss of WAT modifies adipokine secretion and disrupts homeostasis, potentially leading to severe metabolic effects and a reduced quality of life. Doxorubicin is a chemotherapeutic agent used clinically because of its good effectiveness against various types of cancer. However, doxorubicin has deleterious effects in many healthy tissues, including WAT, liver, and skeletal and cardiac muscles. Our objective was to investigate the effects of doxorubicin on white adipocytes through in vivo and in vitro experiments. Doxorubicin reduced the uptake of glucose by retroperitoneal adipocytes and 3T3-L1 cells via the inhibition of AMP-activated protein kinase Thr172 phosphorylation and glucose transporter 4 content. Doxorubicin also reduced the serum level of adiponectin and, to a greater extent, the expression of genes encoding lipogenic (Fas and Acc) and adipogenic factors (Pparg, C/ebpa, and Srebp1c) in retroperitoneal adipose tissue. In addition, doxorubicin inhibited both lipogenesis and lipolysis and reduced the hormone-sensitive lipase and adipose tissue triacylglycerol lipase protein levels. Therefore, our results demonstrate the impact of doxorubicin on WAT. These results are important to understand some side effects observed in patients receiving chemotherapy and should encourage new adjuvant treatments that aim to inhibit these side effects. 相似文献
903.
904.
905.
R. C. Silva F. N. Valentin M. C. F. Paes F. Faustino L. G. Giannecchini P. H. O. Viadanna N. F. Nascimento J. B. K. Fernandes L. S. O. Nakaghi 《Zeitschrift fur angewandte Ichthyologie》2016,32(5):840-847
The aim of this study was to analyse the development of the digestive tract of Siamese fighting fish larvae (Betta splendens Regan, 1910), from hatching to 92 hours post‐hatching (hph) at 28.0°C, in order to determine the most appropriate time to begin exogenous feeding (live feed) and to investigate the digestive tract and its function during larval development. At hatching (29 hours post‐fertilization), the digestive tract was a simple and straight undifferentiated tube lined by a single layer of columnar epithelial cells; the mouth and anus were closed. At 18 hph, the mouth was open. At 32 hph, the tongue was located in the depression of the buccopharyngeal cavity floor and supported by basal cartilage. Goblet cells were present in the epithelium lining the pharynx and oesophagus. At 56 hph, the midgut had four distinct layers: the mucosa with typical villi, the submucosa, the smooth muscle layer, and the serosa. Histological analysis revealed that the larvae retained endogenous yolk reserves until 74 hph. Lipid accumulation was observed in the liver, which coincided with complete yolk absorption. At this time, the digestive tract was fully open and functional. Thus, it can be concluded that live feed should be given to B. splendens larvae from 74 hph onward, when the larvae are able to consume the food provided. This study also provides useful data for the improvement of husbandry techniques and for the formulation of diets specific to ornamental fish larvae. 相似文献
906.
Kozlowski AG Motta-Castro AR Nascimento LB Silva AM Teles SA Villar LM Gaspar AM Martins RM 《Memórias do Instituto Oswaldo Cruz》2007,102(1):121-123
To investigate hepatitis A virus (HAV) infection rates among isolated African-descendant communities in Central Brazil, 947 subjects were interviewed about demographic characteristics in all 12 isolated Afro-descendant communities existing in the state of Mato Grosso do Sul, Central Brazil, between March 2002 and November 2003. Blood samples were collected and sera were tested for HAV antibodies (total and IgM anti-HAV) by enzyme-linked immunosorbent assay. The overall prevalence of HAV infection was 75.6% (95% CI: 72.7-78.3), ranging from 55.4 to 97.3%, depending on the communities studied. The prevalence of anti-HAV increased significantly with age, from 13.8% in the age 0-5 age group to 96.6% in those older than 40 years. The findings point out an intermediate endemicity of HAV infection in some Afro-Brazilian isolated communities in Central Brazil. In addition, the high proportion of susceptible young subjects could be target of future HAV vaccination programs. 相似文献
907.
Marques RC de Sousa AF do Monte SJ Oliveira FE do Nascimento Nogueira N Marreiro DN 《Biological trace element research》2007,120(1-3):11-18
Studies have evidenced that zinc metabolism is altered in presence of Down syndrome, and zinc seems to have a relationship
with the metabolic alterations usually present in this syndrome. In this work, the Zn-related nutritional status of adolescents
with Down syndrome was evaluated by means of biochemical parameters and diet. A case–control study was performed in a group
of adolescents with Down syndrome (n = 30) and a control group (n = 32), of both sexes, aged 10 to 19 years. Diet evaluation was accomplished by using a 3-day dietary record, and the analysis
was performed by the NutWin program, version 1.5. Antropometric measurements were performed for evaluation of body composition.
The Zn-related nutritional status of the groups was evaluated by means of zinc concentration determinations in plasma and
erythrocytes, and 24-h urinary zinc excretion, by using the method of atomic absorption spectroscopy. The diet of both groups
presented adequate concentrations of lipids, proteins, carbohydrates, and zinc. The mean values found for zinc concentration
in erythrocytes were 49.2 ± 8.5 μg Zn/g Hb for the Down syndrome group and 35.9 ± 6.1 μg Zn/g Hb for the control group (p = 0.001). The average values found for zinc concentration in plasma were 67.6 ± 25.6 μg/dL for the Down syndrome group and
68.9 ± 22.3 μg/dL for the control group. The mean values found for zinc concentration in urine were 244.3 ± 194.9 μg Zn/24 h
for the Down syndrome group and 200.3 ± 236.4 μg Zn/24 h for the control group. Assessment of body composition revealed overweight
(26.7%) and obesity (6.6%) in the Down syndrome group. In this study, patients with Down syndrome presented altered zinc levels
for some cellular compartments, and the average zinc concentrations were low in plasma and urine and elevated in erythrocytes. 相似文献
908.
Leonardo D. Slep Otaciro R. Nascimento María T. Garland Mireille Perec 《Inorganica chimica acta》2007,360(9):2911-2916
A seven-coordinate FeIII complex, [Fe(oda)(H2O)2(NO3)], was obtained after dissolving Fe(NO3)3 · 9H2O in an aqueous solution of oxydiacetic acid (H2oda) at room temperature. In the solid state, the FeIII center adopts a pentagonal bipyramid geometry with an {FeO7} core formed by a tridentate oda2− and a bidentate in the equatorial plane, and two axial water molecules. Magnetic measurements and EPR spectra revealed the presence of S = 5/2 FeIII centers with rhombic zero field splitting parameters (D = 0.81 cm−1, E/D = 0.33 ). Weak antiferromagnetic interactions with J ≈ −0.06 cm−1 operating between neighboring Fe ions connected through Fe-O-C-O?H-O-Fe paths are estimated using the molecular field approximation. 相似文献
909.
Marques MG Nicacio AC de Oliveira VP Nascimento AB Caetano HV Mendes CM Mello MR Milazzotto MP Assumpção ME Visintin JA 《Animal reproduction science》2007,97(3-4):375-381
This study evaluated in vitro maturation of pig oocytes in two maturation media (TCM199 and NCSU23) supplemented with 10% porcine follicular fluid (pFF) or 0.1% polyvinyl alcohol (PVA) and four hormonal treatments. The best media was then used to evaluate the effect of reversible meiosis inhibitors cycloheximide (5 microgram/ml) [DOSAGE ERROR CORRECTED]and butyrolactone I (12.5M) on the maturation of pig oocytes was evaluated. After maturation for 44 h, the oocytes were fixed, stained, and examined under epifluorescence microscopy. The comparison of the proportion of oocytes in metaphase II revealed that hormonal treatment 2(incubation for 22 h - 10 ng EGF/ml, 10 IU hCG/ml and 10 IU eCG/ml, followed by incubation for 22 h - 10 ng EGF/ml) presented higher repeatability percentages: TCM+ PVA (54.5% - 61/112); TCM+ pFF (65.0% - 63/97);NCSU23 + PVA (54.6% - 65/119), and NCSU23 + pFF (58.1% - 61/105). The comparison of maturation media showed that TCM199 presented more constant results than NCSU23. Regarding supplementation with pFF or PVA, TCM199 with pFF presented better results. The comparison between butyrolactone I and cycloheximide demonstrated that both drugs effectively inhibited meiosis; however, only cycloheximide presented metaphase II percentages similar to the control (70.29% and 75.49%, respectively). In conclusion, it is recommended the use of TCM199 medium supplemented with pFF and hormonal treatment with 10 ng EGF/ml, 10 UI hCG/mland 10 UI eCG/ml during the first 22 h and more 22 h with 10 ng EGF/ml for the pig oocytes maturation. Butyrolactone I and cycloheximide effectively arrested/resumpted maturation; however, the oocytes percentages in metaphase II was the same for both cycloheximide and the control groups. 相似文献
910.
Jacques H. C. Delabie Benoît Jahyny Ivan Cardoso do Nascimento Cléa S. F. Mariano Sébastien Lacau Sofia Campiolo Stacy M. Philpott Maurice Leponce 《Biodiversity and Conservation》2007,16(8):2359-2384
By maintaining a forest-like structure, shaded cocoa plantations contribute to the conservation of ants that usually live
in the soil, leaf litter or canopy of tropical forests. Here we synthesize the available information on the diversity and
community structure of ants in shaded cocoa plantations in the Atlantic forest region of Brazil, compare ant assemblages in
cocoa agroforests with forests and other forms of agriculture, and discuss how these shaded plantations contribute to the
conservation of the ants in the Atlantic Forest region. We also discuss ants of economical importance and of special interest,
including Camponotus, Dolichoderus, Gnamptogenys, Pachycondyla, Pseudomyrmex and other litter dwelling genera. We discuss the situation of the tramp ant Wasmannia auropunctata in the Bahian cocoa-producing region where it is considered as native, and that of the two cryptobiotic genera Thaumatomyrmex and Typhlomyrmex, as well as that of proven and possible endangered army ant and Ponerini species. A total of 192 ant species from four strata
were found in extensive sampling of a cocoa plantation with a relatively simple shade canopy (comprised primarily of Erythrina). Species richness in the cocoa plantations corresponded roughly to that of low diversity native forests, and species composition
of cocoa plantations was most similar to native habitats (forest and mangroves) while ant composition in other agricultural
habitats was most similar to that of urban areas. Although occurrences of Wasmannia auropunctata were similar in cocoa plantations and forests, abundance of Thaumatomyrmex and Typhlomyrmex, generally thought to be rare ants, was relatively high in cocoa plantations. These results, from cocoa plantations with
relatively simple shade, demonstrate the importance of cocoa for ant conservation in the Atlantic forest region of Brazil.
It is likely that cocoa plantations with a greater number of vegetation strata and higher tree species richness (such as traditional
cabruca plantations) provide even more important habitat for ants generally and for ant species of conservation concern. 相似文献