首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   39068篇
  免费   254篇
  国内免费   12篇
耳鼻咽喉   397篇
儿科学   434篇
妇产科学   893篇
基础医学   6644篇
口腔科学   1325篇
临床医学   3611篇
内科学   4089篇
皮肤病学   243篇
神经病学   2778篇
特种医学   1773篇
外科学   4472篇
综合类   216篇
一般理论   6篇
预防医学   2356篇
眼科学   375篇
药学   5435篇
中国医学   682篇
肿瘤学   3605篇
  2024年   15篇
  2023年   680篇
  2022年   1328篇
  2021年   1428篇
  2020年   1599篇
  2019年   1280篇
  2018年   957篇
  2017年   1187篇
  2016年   1329篇
  2015年   1226篇
  2014年   2394篇
  2013年   1745篇
  2012年   2792篇
  2011年   2583篇
  2010年   2102篇
  2009年   2163篇
  2008年   1982篇
  2007年   1938篇
  2006年   1598篇
  2005年   1237篇
  2004年   1167篇
  2003年   1007篇
  2002年   657篇
  2001年   571篇
  2000年   446篇
  1999年   474篇
  1998年   398篇
  1997年   324篇
  1996年   402篇
  1995年   339篇
  1994年   238篇
  1993年   174篇
  1992年   118篇
  1991年   121篇
  1990年   126篇
  1989年   106篇
  1988年   186篇
  1987年   204篇
  1986年   220篇
  1985年   47篇
  1984年   87篇
  1983年   65篇
  1982年   73篇
  1981年   91篇
  1980年   46篇
  1979年   18篇
  1978年   23篇
  1977年   24篇
  1976年   19篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
181.
ObjectiveThe aim of the study was to determine how well self-reported adherence fares compared to therapeutic drug monitoring in monitoring HAART adherence.MethodsWe administered a validated self-reported adherence (SRA) questionnaire to 925 HIV patients on HAART in a large Malaysian hospital from 2010 to 11. We also performed Therapeutic Drug monitoring (TDM) by concurrently collecting and testing blood samples for Efavirenz, Nevirapine and Lamivudine using Liquid Chromatography/Mass Spectrometry. We compared the SRA against the TDM results. Sensitivity, specificity, positive (PPV) and negative predictive (NPV) and diagnostic accuracy values were computed for each drug.ResultsSelf-reported adherence (SRA) over-estimates adherence by between 6 and 10 percentage points compared to therapeutic drug monitoring (TDM). SRA is highly sensitive with sensitivity exceeding 0.90 but is not very specific (0.56–0.63). PPV for SRA ranged between 0.76 (Lamivudine) and 0.84 (Efavirenz) while NPV ranged between 0.78 (Lamivudine) and 0.81 (Efavirenz). Overall diagnostic accuracy ranged between 0.76 (Lamivudine) and 0.84 (Nevirapine).ConclusionSelf-reported adherence is a surprisingly accurate instrument for measuring HAART adherence compared to TDM and can be reliably used in practice in resource-poor settings.  相似文献   
182.
DNA vaccination has caught the attention of many for triggering humoral as well as cellular immune responses. And delivering DNA into the antigen presenting cells (APCs) in order to induce efficient immunoresponse has become the backbone of this field. It has been confirmed that Saccharomyces cerevisiae, though non-pathogenic, is being engulfed by the dendritic cells and macrophages and delivers not only proteins, but also DNA materials (already confirmed in vitro). In this research, S. cerevisiae is used to deliver green fluorescent protein (GFP) reporter gene controlled under cytomegalovirus (CMV) promoter in living organism (mice). The recombinant yeast, transfected with the plasmid containing the GFP gene, was heat killed and orally administered to mice. After 60 h of yeast administration, mice were sacrificed and intestine was separated, washed and frozen in liquid nitrogen. Tissues were cut at the size of 10 μm using Cryostat machine, and GFP expression was successfully detected under a fluorescence microscope. After 45 days Western blot was able to detect GFP antibody in the blood of mice. These results imply that S. cerevisiae, being non-pathogenic, cheap, and easy to culture could be a good candidate to deliver DNA materials to the immune cells for vaccination.  相似文献   
183.
Around the world clinical professionals have increased their involvement in the management of health services. However the evidence to suggest that these changes will lead to improved performance remains fragmented. In this paper we address this matter focussing on the impact of clinicians appointed to the boards of directors of English NHS hospital trusts. Although the number of clinicians involved in the strategic governance of hospital trusts is relatively low by international standards, they do appear to have an impact on overall performance. Drawing on published information from hospital trust annual reports, publicly available performance measures from the Healthcare Commission and data gathered by Dr Foster over a three year period (2006–9), the paper reports two main findings. First, the analysis reveals a significant and positive association between a higher percentage of clinicians on boards and the quality ratings of service providers, especially where doctors are concerned. This positive influence is also confirmed in relation to lower morbidity rates and tests to exclude the possibility of reverse causality (doctors joining boards of already successful organisations). Second, we do not find the same level of support for clinical professions such as nurses and other allied health professions turned directors.  相似文献   
184.
185.
186.
The Lyme borreliosis (LB) group of spirochaetes currently comprises 18 named species that vary in their geographic distribution, host specificity and ability to cause disease in humans. In Europe three species are most abundant, Borrelia afzelii, Borrelia garinii and Borrelia valaisiana but only two of these (B. garinii and B. afzelii) are regularly found in Asia as well. A recently published study has shown that Borrelia species associated with birds, such as B. garinii, showed limited geographic structuring between European countries while, the rodent associated species, B. afzelii, showed extensive spatial structuring in Europe. Here, we use multilocus sequence analysis to show that when the wider, inter-continental, distribution is considered, there is evidence of spatial structuring even in the bird-associated species B. garinii. Furthermore, our investigations into historical LB populations provided evidence for range expansions of B. garinii and B. afzelii populations in Europe in the distant past. We propose that the expansion of B. afzelii in Europe may be linked to rodent population expansions after the last glacial maximum.  相似文献   
187.
Urolithins were the metabolites of ellagic acid by intestinal flora in gastrointestinal tract. In previous research, it was found that urolithins could mainly inhibit prostate cancer and colon cancer cell growth. However, there is no report about bladder cancer therapy of urolithins. In this paper, three urolithin-type compounds (urolithin A, urolithin B, 8-OMe-urolithin A) and ellagic acid were evaluated for antiproliferative activity in vitro against human bladder cancer cell lines T24. The IC50 values for T24 cell inhibition were 43.9, 35.2, 46.3 and 33.7 μM for urolithin A, urolithin B, 8-OMe-urolithin A and ellagic acid, respectively. After the administration of urolithins and ellagic acid, we found these compounds could increase mRNA and protein expression of Phospho-p38 MAPK, and decrease mRNA and protein expression of MEKK1 and Phospho-c-Jun in T24 cells. Caspase-3 was also activated and PPAR-γ protein expression increased in drug-induced apoptosis. And what’s more, the antioxidant assay afforded by three urolithins and EA treatments were associated with decreases in the intracellular ROS and MDA levels, and increased SOD activity in H2O2-treated T24 cells. The results suggested that these compounds could inhibit cell proliferation by p38-MAPK and/or c-Jun medicated caspase-3 activation and reduce the oxidative stress status in bladder cancer.  相似文献   
188.
Hyperglycemia is associated with advanced glycation end products (AGEs). Recently, AGEs were found to cause pancreatic damage, oxidative stress, and hyperglycemia through the AGE receptor. Carboxymethyllysine (CML) is an AGE but whether it induces pancreatic dysfunction remains unclear. Graptopetalum paraguayense, a vegetable consumed in Taiwan, has been used in folk medicine and is an antioxidant that protects against liver damage. We investigated the protective properties of G. paraguayense 95% ethanol extracts (GPEs) against CML-induced pancreatic damage. The results indicated that resveratrol, GPE, and gallic acid (the active compound of GPE) increased insulin synthesis via upregulation of pancreatic peroxisome proliferator activated-receptor-γ (PPARγ) and pancreatic-duodenal homeobox-1 (PDX-1) but inhibited the expression of CML-mediated CCAAT/enhancer binding protein-β (C/EBPβ), a negative regulator of insulin production. Moreover, resveratrol and GPE also strongly activated nuclear factor-erythroid 2-related factor 2 (Nrf2) to attenuate oxidative stress and improve insulin sensitivity in the liver and muscle of CML-injected C57BL/6 mice and resulted in reduced blood glucose levels. Taken together, these findings suggested that GPE and gallic acid could potentially be used as a food supplement to protect against pancreatic damage and the development of diabetes.  相似文献   
189.
Rhein, a lipophilic anthraquinone, exhibits anti-inflammatory and anti-tumor activities; however, it is hepatotoxic. ATP-binding cassette transporters, including P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and multidrug resistance-associated protein 2 (MRP2), can pump toxicants from gut epithelial cells back into the intestinal lumen to prevent poisoning. We investigated their roles in rhein transport using a rat intestinal perfusion model and Caco-2, MDCKII-MDR1 (high expression of P-gp), MDCKII-BCRP (high expression of BCRP) and MDCKII-MRP2 (high expression of MRP2) cell models. The permeability of rhein in the duodenum significantly increased with increasing perfused concentration of rhein in the rat model, suggesting that efflux transporters were involved in rhein transport. In the Caco-2 cells, the permeability of rhein from the basolateral (B) to the apical (A) was significantly higher than that from A to B. In the presence of BCRP or MRP2 inhibitor, the permeability of rhein significantly decreased from B to A direction. In the MDCKII-BCRP cells, rhein was more permeable in B to A side than that in the opposite side. However, no significant differences of rhein permeability were observed in two directions in both MDCKII-MDR1 and MDCKII-MRP2 cells. Taken together, these results suggested that only BCRP was involved in rhein transport.  相似文献   
190.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号