全文获取类型
收费全文 | 1803篇 |
免费 | 116篇 |
出版年
2024年 | 2篇 |
2023年 | 13篇 |
2022年 | 28篇 |
2021年 | 72篇 |
2020年 | 34篇 |
2019年 | 44篇 |
2018年 | 58篇 |
2017年 | 40篇 |
2016年 | 63篇 |
2015年 | 109篇 |
2014年 | 101篇 |
2013年 | 148篇 |
2012年 | 185篇 |
2011年 | 203篇 |
2010年 | 104篇 |
2009年 | 96篇 |
2008年 | 116篇 |
2007年 | 92篇 |
2006年 | 88篇 |
2005年 | 77篇 |
2004年 | 80篇 |
2003年 | 59篇 |
2002年 | 49篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1994年 | 1篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有1919条查询结果,搜索用时 31 毫秒
981.
Braido F Baiardini I Menoni S Gani F Senna GE Ridolo E Schoepf V Rogkakou A Canonica GW 《PloS one》2012,7(2):e31178
Objectives
Asthma trials suggest that patients reaching total disease control have an optimal Health Related Quality of Life (HRQoL). Moreover, rhinitis is present in almost 80% of asthmatics and impacts asthma control and patient HRQoL. We explored whether optimal HRQoL was reachable in a real-life setting, and evaluated the disease and patient related patterns associated to optimal HRQoL achievement.Methods and Findings
Asthma and rhinitis HRQoL, illness perception, mood profiles, rhinitis symptoms and asthma control were assessed by means of validated tools in patients classified according to GINA and ARIA guidelines. Optimal HRQoL, identified by a Rhinasthma Global Summary (GS) score ≤20 (score ranging from 0 to 100, where 100 represents the worst possible HRQoL), was reached by 78/209 (37.32%). With the exception of age, no associations were found between clinical and demographic characteristics and optimal HRQoL achievement. Patients reaching an optimal HRQoL differed in disease perception and mood compared to those not reaching an optimal HRQoL. Asthma control was significantly associated with optimal HRQoL (χ2 = 49.599; p<0.001) and well-controlled and totally controlled patients significantly differed in achieving optimal HRQoL (χ2 = 7.617; p<0.006).Conclusion
Approximately one third of the patients in our survey were found to have an optimal HRQoL. While unsatisfactory disease control was the primary reason why the remainder failed to attain optimal HRQoL, it is clear that illness perception and mood also played parts. Therefore, therapeutic plans should be directed not only toward achieving the best possible clinical control of asthma and comorbid rhinitis, but also to incorporating individualized elements according to patient-related characteristics. 相似文献982.
Tavella S Ruggiu A Giuliani A Brun F Canciani B Manescu A Marozzi K Cilli M Costa D Liu Y Piccardi F Tasso R Tromba G Rustichelli F Cancedda R 《PloS one》2012,7(3):e33179
Bone is a complex dynamic tissue undergoing a continuous remodeling process. Gravity is a physical force playing a role in the remodeling and contributing to the maintenance of bone integrity. This article reports an investigation on the alterations of the bone microarchitecture that occurred in wild type (Wt) and pleiotrophin-transgenic (PTN-Tg) mice exposed to a near-zero gravity on the International Space Station (ISS) during the Mice Drawer System (MDS) mission, to date, the longest mice permanence (91 days) in space. The transgenic mouse strain over-expressing pleiotrophin (PTN) in bone was selected because of the PTN positive effects on bone turnover. Wt and PTN-Tg control animals were maintained on Earth either in a MDS payload or in a standard vivarium cage. This study revealed a bone loss during spaceflight in the weight-bearing bones of both strains. For both Tg and Wt a decrease of the trabecular number as well as an increase of the mean trabecular separation was observed after flight, whereas trabecular thickness did not show any significant change. Non weight-bearing bones were not affected. The PTN-Tg mice exposed to normal gravity presented a poorer trabecular organization than Wt mice, but interestingly, the expression of the PTN transgene during the flight resulted in some protection against microgravity's negative effects. Moreover, osteocytes of the Wt mice, but not of Tg mice, acquired a round shape, thus showing for the first time osteocyte space-related morphological alterations in vivo. The analysis of specific bone formation and resorption marker expression suggested that the microgravity-induced bone loss was due to both an increased bone resorption and a decreased bone deposition. Apparently, the PTN transgene protection was the result of a higher osteoblast activity in the flight mice. 相似文献
983.
Maria Gisella Cavallo Federica Sentinelli Ilaria Barchetta Carmine Costantino Michela Incani Laura Perra Danila Capoccia Stefano Romeo Efisio Cossu Frida Leonetti Luciano Agati Marco G. Baroni 《PloS one》2012,7(12)
Background
Apelin is an adipokine that plays a role in the regulation of glucose homeostasis and in obesity. The relationship between apelin serum concentration and dysmetabolic conditions such as type 2 diabetes (T2D) is still controversial. Aims of our study are: 1) determine the circulating levels of apelin in a large cohort of Italian subjects with T2D, T1D and in non-diabetic controls; 2) identify putative metabolic determinants of modified apelin concentrations, in order to search possible mechanism of apelin control; 3) investigate changes in apelin levels in response to sharp modifications of glucose/insulin metabolism in T2D obese subjects before and 3 days after bariatric surgery.Methods
We recruited 369 subjects, 119 with T2D, 113 with T1D and 137 non-diabetic controls. All subjects underwent a complete clinical examination, including anthropometric and laboratory measurements. Serum apelin levels were determined by EIA (immunoenzyme assay).Results
Patients with T2D had significantly higher serum apelin levels compared to controls (1.23±1.1 ng/mL vs 0.91±0.7 ng/mL, P<0.001) and to T1D subjects (0.73±0.39 ng/mL, P<0.001). Controls and T1D subjects did not differ significantly in apelin levels. Apelin concentrations were directly associated with fasting blood glucose (FBG), body mass index (BMI), basal Disposition Index (DI-0), age, and diagnosis of T2D at bivariate correlation analysis. Multiple regression analysis confirmed that diagnosis of T2D, basal DI-0 and FBG were all determinants of serum apelin levels independently from age and BMI. Bariatric surgery performed in a subgroup of obese diabetic subjects (n = 12) resulted in a significant reduction of apelin concentrations compared to baseline levels (P = 0.01).Conclusions
Our study demonstrates that T2D, but not T1D, is associated with increased serum apelin levels compared to non-diabetic subjects. This association is dependent on impaired glucose homeostasis, and disappears after bariatric surgery, providing further evidence regarding the relationship between apelin and the regulation of glucose metabolism. 相似文献984.
Cabras T Manconi B Iavarone F Fanali C Nemolato S Fiorita A Scarano E Passali GC Manni A Cordaro M Paludetti G Faa G Messana I Castagnola M 《Journal of Proteomics》2012,75(3):908-913
An HPLC-ESI-MS analysis of adult human whole saliva evidenced three protein masses (M average 11,487 ± 2, 11,301 ± 2 and 22,362 ± 3 Da) eluting in the 32.5-35.0 min range. Treatment in reducing conditions allowed establishing that they are S-derivatives of N-terminal acetylated cystatin B, namely its S-glutathionyl, S-cysteinyl and S-S dimer. The identification was confirmed by high resolution HPLC-ESI-MS-MS experiments on the intact naturally occurring proteins and their tryptic digests. S-unmodified cystatin B is rarely detectable in whole saliva of healthy adults (5 subjects out of 65) and its percentage does not overcome approximately 20% of total cystatin B (11 ± 9%). In the majority of subjects (60 out of 65) the mean percentages of the S-modified derivatives were S-glutathionyl 53 ± 13%, S-cysteinyl 15 ± 5%, S-S 2-mer 32 ± 13%. Variations of the percentages of these S-modified derivatives of cystatin B could be indicative of oral oxidative stress. As we are aware, this is the first time that S-glutathionylation and S-cysteinylation were described as extensive PTM of a salivary protein and the first time that these PTMs were detected in naturally occurring cystatin B. 相似文献
985.
Del Chierico F Masotti A Onori M Fiscarelli E Mancinelli L Ricciotti G Alghisi F Dimiziani L Manetti C Urbani A Muraca M Putignani L 《Journal of Proteomics》2012,75(11):3314-3330
Major changes in medical, intensive care and organ transplantation practices are drastically increasing the risk of fungal opportunistic infections. We designed and set-up a MALDI-TOF MS-based assay to identify the most isolated and emerging therapy-refractory/uncommon fungi from cystic fibrosis (CF) and immunocompromised patients. Two-hundred and thirty isolates from 10 different genera (Aspergillus, Emericella, Fusarium, Geosmithia, Neosartorya, Penicillium, Pseudallescheria, Scedosporium, Talaromyces, Fomitopsis), investigated during routine diagnostic efforts, were correlated to 22 laboratory-adapted reference MALDI-TOF MS "proteomic phenotypes". A growth time-course at 30°C on Sabouraud agar medium was performed for the 22 "phenotypes" at 48, 72, 96 and 120h points. The best peptide extraction conditions for full recovery of conidia- or asci-producing multihyphal morph structures and the highest intra- and inter-class profiling correlation were identified for the 120h point spectra dataset, from which an engineered library derived (pre-analytical phase). Fingerprinting classifiers, selected by Wilcoxon/Kruskal-Wallis algorithm, were computed by Genetic Algorithm, Support Vector Machine, Supervised Neuronal Network and Quick Classifier model construction. MS identification (ID) of clinical isolates was referred to genotyping (GT) and, retrospectively, compared to routine morphotyping (MT) IDs (analytical phase). Proteomic phenotyping is revolutionizing diagnostic mycology as fully reflecting species/morph varieties but often overcoming taxonomic hindrance. 相似文献
986.
Lupattelli G Siepi D De Vuono S Roscini AR Crisanti F Covelli D Pirro M Mannarino E 《Life sciences》2012,90(21-22):846-850
AimNon-cholesterol sterols reflect cholesterol metabolism. Statins reduce cholesterol synthesis usually with a rise in cholesterol absorption. Common hyperlipemias have shown different patterns of cholesterol metabolism. We evaluated whether cholesterol absorption and synthesis may differ after statin therapy in primary hyperlipemias.Main methodsWe determined lipid profile, apoprotein B and serum sterols (lathosterol, sitosterol, campesterol by gas chromatography/mass spectrometry) before and after statins in 80 untreated hyperlipemic patients, 40 with polygenic hypercholesterolemia (PH) and 40 with familial combined hyperlipemia (FCH).Key findingsAt baseline in FCH lathosterol was significantly higher while campesterol and sitosterol were significantly lower than in PH. After statins, the reduction in LDL-C did not significantly differ between the two groups; in PH there was a significant decrease of lathosterol from 96.1 to 52.6 102 μmol/mmol cholesterol (p = 0.0001) with no significant modifications in campesterol and sitosterol; on the opposite, in FCH lathosterol decreased from 117 to 43 102 μmol/mmol cholesterol (p = 0.0001) and campesterol and sitosterol significantly increased from 38 to 48 102 μmol/mmol cholesterol (p = 0.0001), and from 75 to 86 102 μmol/mmol cholesterol, (p = 0.022), respectively. After statin therapy only in FCH Δ-LDL-C showed a significant inverse correlation with Δ-sitosterol and with Δ-campesterol.SignificancePrimary hyperlipemias show different patterns of response to statins: in PH LDL reduction appears completely “synthesis inhibition” dependent, while in FCH LDL decrease appears to be synthesis dependent, partially limited by absorption increase. Studying cholesterol metabolism before and after hypolipemic therapy might be useful in identifying the best tailored treatment. 相似文献
987.
988.
Romano V Pasquale V Krovacek K Mauri F Demarta A Dumontet S 《Applied and environmental microbiology》2012,78(18):6643-6646
The occurrence of Clostridium difficile in nine wastewater treatment plants in the Ticino Canton (southern Switzerland) was investigated. The samples were collected from raw sewage influents and from treated effluents. Forty-seven out of 55 characterized C. difficile strains belonged to 13 different reference PCR ribotypes (009, 010, 014, 015, 039, 052, 053, 066, 070, 078, 101, 106, and 117), whereas 8 strains did not match any of those available in our libraries. The most frequently isolated ribotype (40%) was 078, isolated from six wastewater treatment plants, whereas ribotype 066, a toxigenic emerging ribotype isolated from patients admitted to hospitals in Europe and Switzerland, was isolated from the outgoing effluent of one plant. The majority of the isolates (85%) were toxigenic. Forty-nine percent of them produced toxin A, toxin B, and the binary toxin (toxigenic profile A(+) B(+) CDT(+)), whereas 51% showed the profile A(+) B(+) CDT(-). Interestingly, eight ribotypes (010, 014, 015, 039, 066, 078, 101, and 106) were among the riboprofiles isolated from symptomatic patients admitted to the hospitals of the Ticino Canton in 2010. Despite the limitation of sampling, this study highlights that toxigenic ribotypes of C. difficile involved in human infections may occur in both incoming and outgoing biological wastewater treatment plants. Such a finding raises concern about the possible contamination of water bodies that receive wastewater treatment plant effluents and about the safe reuse of treated wastewater. 相似文献
989.
The effect of aging and CDP-choline treatment (20 mg kg−1 body weight i.p. for 28 days) on the maximal rates (Vmax) of representative mitochondrial enzyme activities related to Krebs’ cycle (citrate synthase, α-ketoglutarate dehydrogenase, malate dehydrogenase), glutamate and related amino acid metabolism (glutamate dehydrogenase, glutamate–oxaloacetate- and glutamate–pyruvate transaminases) were evaluated in non-synaptic and intra-synaptic “light” and “heavy” mitochondria from frontal cerebral cortex of male Wistar rats aged 4, 12, 18 and 24 months. 相似文献
990.