全文获取类型
收费全文 | 39068篇 |
免费 | 254篇 |
国内免费 | 12篇 |
专业分类
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 |
出版年
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.
Gene delivery to dendritic cells by orally administered recombinant Saccharomyces cerevisiae in mice
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.