全文获取类型
收费全文 | 1250篇 |
免费 | 120篇 |
国内免费 | 111篇 |
出版年
2024年 | 6篇 |
2023年 | 26篇 |
2022年 | 55篇 |
2021年 | 65篇 |
2020年 | 61篇 |
2019年 | 55篇 |
2018年 | 50篇 |
2017年 | 53篇 |
2016年 | 63篇 |
2015年 | 81篇 |
2014年 | 96篇 |
2013年 | 86篇 |
2012年 | 107篇 |
2011年 | 89篇 |
2010年 | 83篇 |
2009年 | 58篇 |
2008年 | 89篇 |
2007年 | 63篇 |
2006年 | 44篇 |
2005年 | 45篇 |
2004年 | 42篇 |
2003年 | 34篇 |
2002年 | 32篇 |
2001年 | 14篇 |
2000年 | 7篇 |
1999年 | 13篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有1481条查询结果,搜索用时 31 毫秒
921.
922.
Anderson JA Archin NM Ince W Parker D Wiegand A Coffin JM Kuruc J Eron J Swanstrom R Margolis DM 《Journal of virology》2011,85(10):5220-5223
Despite successful antiretroviral therapy (ART), low-level viremia (LLV) may be intermittently detected in most HIV-infected patients. Longitudinal blood plasma and resting CD4(+) T cells were obtained from two patients on suppressive ART to investigate the source of LLV. Single-genome sequencing of HIV-1 env from LLV plasma was performed, and the sequences were compared to sequences recovered from limiting-dilution outgrowth assays of resting CD4(+) T cells. The circulating LLV virus clone was identical to virus recovered from outgrowth assays from pools of millions of resting CD4(+) T cells. Understanding the sources of LLV requires evaluation of all possible reservoirs of persistent HIV infection. 相似文献
923.
Amperometric glucose biosensors have been developed based on entrapment on platinum (Pt) electrode using cyclic voltammetry
technique in glucose oxidase (GOD) and pyrrole containing p-toluenesulfonic acid (pTSA) or sodium p-toluenesulfonate (NapTS) as supporting electrolyte solutions. Both of electrolyte solutions were suitable media for the formation
and deposition of polypyrrole-GOD (PPy-GOD) layers on Pt substrate. Pt/PPy-GOD electrodes brought about in different morphological
properties as well as different electrochemical and biochemical response. The highest responses obtained in pTSA and NapTS
electrolytes were observed at pH of 4.5 and 7.0 for Pt/PPy-GOD electrodes, respectively. While linearity was observed between
0.0–1.0 mM glucose substrate for both electrodes, I
max value of Pt/PPy-GODNapTS electrode was approximately twice as high as that of Pt/PPy-GODpTSA electrode as 25.4 and 14.2 μA, respectively. Five commercial drinks were tested with enzyme electrodes and compared with
results obtained spectropho-tometrically using glucose kit. Results revealed that Pt/PPy-GODNapTS electrode exhibited better biosensor response. 相似文献
924.
Peixoto PL Nascimento E Cançado GG Miranda RR Rocha RL Araújo RN Fujiwara RT 《Memórias do Instituto Oswaldo Cruz》2011,106(2):200-206
In the present work, we identified adult Toxocara canis antigens through sodium dodecyl sulfate-polyacrylamide gel electrophoresis for potential use in human toxocariasis immunodiagnosis. The sensitivity and specificity of several semi-purified antigens, as well as their cross-reactivity with other parasitic infections, were assessed by IgM and IgG-enzime linked immunosorbent assay. Whilst we found that the crude extract of the parasite presented limited sensitivity, specificity and high cross-reactivity against other parasites, we identified 42, 58, 68 and 97-kDa semi-purified antigens as the most promising candidates for immunodiagnosis. Moreover, the 58 and 68-kDa antigens presented the lowest IgM cross-reactivity. When tested as a combination, a mixture of the 58 and 68-kDa antigens presented 100% sensitivity and specificity, as well as minor cross-reactivity. Although the combination of the 42, 58, 68 and 97-kDa antigens presented 100% sensitivity at a dilution of 1:40, the low specificity and high cross-reactivity observed suggested a limited use for diagnostic purposes. Our data suggested that the 58 and 68-kDa antigens might be most suitable for the immunodiagnosis of human toxocariasis. 相似文献
925.
Zhang Y Tian C Zhang J Li X Wan H He C Guo L Meilang Q Peng C Duo L Huang J Fan H 《Immunogenetics》2011,63(1):23-32
The -159C/T polymorphism in the CD14 gene has been implicated in susceptibility to asthma, but a large number of studies have reported inconclusive results. The aim of this study is to investigate the association between the -159C/T polymorphism in the CD14 gene and the risk of asthma by meta-analysis. We searched Pubmed, Embase, CNKI database, Wanfang database, Weipu database, and Chinese Biomedical database, covering all publications (last search been performed on April 20, 2010). Statistical analysis was performed by using the softwares Revman 4.2 and STATA 10.0. A total of 17 case-control studies in 17 articles (4,246 cases and 3,631 controls) were included in this meta-analysis. There was no association between this polymorphism and asthma risk in combined analyses (odds ratio (OR)?=?0.86 and 95% confidence interval (95% CI)?=?0.72-1.02, P?=?0.09 for TC?+?TT vs. CC). In the subgroup analysis by age, ethnicity, and atopic status, no significant associations of asthma risks were obtained from age groups, ethnic groups, and atopic groups for TC?+?TT vs. CC comparison. For atopic population, significant decreased atopic asthma risks were found among Asian population (OR?=?0.69, 95% CI 0.52-0.92, P?=?0.01) and children population (OR?=?0.69, 95% CI 0.54-0.89, P?=?0.0004) for TC?+?TT vs. CC comparison. This meta-analysis suggests that CD14 is a candidate gene for atopic asthma susceptibility. The -159C/T polymorphism may be a protective factor for atopic asthma in Asian and children. More studies are needed to validate these associations. 相似文献
926.
The peptide repertoire presented on human leukocyte antigen (HLA) class I molecules is largely determined by the structure
of the peptide binding groove. It is expected that the molecules having similar grooves (i.e., belonging to the same supertype)
might present similar/overlapping peptides. However, the extent of promiscuity among HLA class I ligands remains controversial:
while in many studies T cell responses are detected against epitopes presented by alternative molecules across HLA class I
supertypes and loci, peptide elution studies report minute overlaps between the peptide repertoires of even related HLA molecules.
To get more insight into the promiscuous peptide binding by HLA molecules, we analyzed the HLA peptide binding data from the
large epitope repository, Immune Epitope Database (IEDB), and further performed in silico analysis to estimate the promiscuity
at the population level. Both analyses suggest that an unexpectedly large fraction of HLA ligands (>50%) bind two or more
HLA molecules, often across supertype or even loci. These results suggest that different HLA class I molecules can nevertheless
present largely overlapping peptide sets, and that “functional” HLA polymorphism on individual and population level is probably
much lower than previously anticipated. 相似文献
927.
Influence of vanadium supplementation on oxidative stress factors in the muscle of STZ-diabetic rats
Ozlem Kurt Tugba Yilmaz Ozden Nurten Ozsoy Sevim Tunali Ayse Can Nuriye Akev Refiye Yanardag 《Biometals》2011,24(5):943-949
In recent years, the role of free radical damage consequent to oxidative stress is widely discussed in diabetic complications. In this aspect, the protection of cell integrity by trace elements is a topic to be investigated. Vanadium is a trace element believed to be important for normal cell function and development. The aim of the present study was to investigate the effect of vanadyl sulfate supplementation on the antioxidant system in the muscle tissue of diabetic rats. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ, 65 mg/kg body weight) to male Swiss albino rats. The rats were randomly divided into 4 groups: Group I, control; Group II, vanadyl sulfate control; Group III, STZ-diabetic untreated; Group IV, STZ-diabetic treated with vanadyl sulfate. Vanadyl sulfate (100 mg/kg) was given daily by gavage for 60 days. At the last day of the experiment, rats were killed, muscle tissues were taken, homogenized in cold saline to make a 10% (w/v) homogenate. Body weights and blood glucose levels were estimated at 0, 30 and 60th days. Antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST), as well as carbonic anhydrase (CA), myeloperoxidase (MPO) activities and protein carbonyl content (PCC) were determined in muscle tissue. Vanadyl sulfate administration improved the loss in body weight due to STZ-induced diabetes and decreased the rise in blood glucose levels. It was shown that vanadium supplementation to diabetic rats significantly decrease serum antioxidant enzyme levels, which were significantly raised by diabetes in muscle tissue showing that this trace element could be used as preventive for diabetic complications. 相似文献
928.
We aimed to determine the oxidative stress and antioxidant status in preeclamptic placenta. Also, we investigated the apoptotic index of villous trophoblast and proliferation index of cytotrophoblasts. The study included 32 pregnant with preeclampsia and 31 normotensive healthy pregnant women. Malondialdehyde (MDA) and total antioxidant status (TAS) levels were measured in the placenta. For detection of apoptosis and proliferation in trophoblast, apoptosis protease activating factor 1 (APAF-1) and Ki-67 were used. Placental MDA levels in preeclamptic women were significantly higher than normal pregnancies (p = 0.002). There was no significant difference between the groups in the TAS levels of placenta (p = 0.773). Also, the apoptotic index in villous trophoblasts increased (p < 0.001), but proliferation index did not change in preeclampsia (p = 0.850). Increased oxidative stress and apoptosis in pathological placenta are not balanced by antioxidant systems and proliferation mechanisms. 相似文献
929.
Hilal Gokturk N. Nuray Ulusu Muslum Gok Erkan Tuncay Belgin Can Belma Turan 《Molecular and cellular biochemistry》2014,387(1-2):177-186
Mutations in Ras isoforms such as K-Ras, N-Ras, and H-Ras contribute to roughly 85, 15, and 1 % of human cancers, respectively. Proper membrane targeting of these Ras isoforms, a prerequisite for Ras activity, requires farnesylation or geranylgeranylation at the C-terminal CAAX box. We devised an in vivo screening strategy based on monitoring Ras activation and phenotypic physiological outputs for assaying synthetic Ras function inhibitors (RFI). Ras activity was visualized by the translocation of RBD Raf1 -GFP to activated Ras at the plasma membrane. By using this strategy, we screened one synthetic farnesyl substrate analog (AGOH) along with nine putative inhibitors and found that only m-CN-AGOH inhibited Ras activation. Phenotypic analysis of starving cells could be used to monitor polarization, motility, and the inability of these treated cells to aggregate properly during fruiting body formation. Incorporation of AGOH and m-CN-AGOH to cellular proteins was detected by western blot. These screening assays can be incorporated into a high throughput screening format using Dictyostelium discoideum and automated microscopy to determine effective RFIs. These RFI candidates can then be further tested in mammalian systems. 相似文献
930.