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   13512篇
  免费   1309篇
  国内免费   23篇
耳鼻咽喉   111篇
儿科学   383篇
妇产科学   241篇
基础医学   1805篇
口腔科学   263篇
临床医学   1629篇
内科学   2545篇
皮肤病学   120篇
神经病学   1184篇
特种医学   383篇
外国民族医学   1篇
外科学   2266篇
综合类   364篇
一般理论   12篇
预防医学   1524篇
眼科学   246篇
药学   893篇
中国医学   29篇
肿瘤学   845篇
  2023年   117篇
  2022年   142篇
  2021年   327篇
  2020年   220篇
  2019年   298篇
  2018年   373篇
  2017年   281篇
  2016年   266篇
  2015年   300篇
  2014年   439篇
  2013年   634篇
  2012年   906篇
  2011年   896篇
  2010年   500篇
  2009年   421篇
  2008年   699篇
  2007年   799篇
  2006年   694篇
  2005年   676篇
  2004年   667篇
  2003年   586篇
  2002年   575篇
  2001年   260篇
  2000年   242篇
  1999年   225篇
  1998年   157篇
  1997年   133篇
  1996年   97篇
  1995年   99篇
  1994年   107篇
  1993年   75篇
  1992年   185篇
  1991年   184篇
  1990年   171篇
  1989年   141篇
  1988年   139篇
  1987年   116篇
  1986年   138篇
  1985年   125篇
  1984年   113篇
  1983年   94篇
  1982年   69篇
  1981年   59篇
  1980年   56篇
  1979年   87篇
  1978年   80篇
  1975年   56篇
  1974年   62篇
  1973年   75篇
  1972年   76篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Journal of Behavioral Medicine - Evidence supports the use of graphic warnings to educate the public about the health harms of smoking and suggests warnings eliciting negative emotional responses...  相似文献   
2.
3.
In 1998 Howard Parker, Judith Aldridge & Fiona Measham published Illegal Leisure, a ground‐breaking study of profound changes in British youth cultures in the 1990s, and the place of drugs and drug use in these upheavals. This work introduced the ‘normalization thesis’ to the social sciences, offering a novel vocabulary for re‐imagining the normative character of young people's attitudes towards and experiences of illicit drug use. Arriving at the dawn of the new century, the book offered a thoroughgoing re‐thinking of the character of youth cultures at a time of great social, cultural, economic and technological disruption. In so doing, the book deftly anticipated many of the most interesting currents of critical drug studies that followed.  相似文献   
4.
Owing to the frequent incidence of blast-induced traumatic brain injury (bTBI) in recent military conflicts, there is an urgent need to develop effective therapies for bTBI-related pathologies. Blood-brain barrier (BBB) breakdown has been reported to occur after primary blast exposure, making restoration of BBB function and integrity a promising therapeutic target. We tested the hypothesis that treatment with dexamethasone (DEX) after primary blast injury potentiates recovery of an in vitro BBB model consisting of mouse brain endothelial cells (bEnd.3). DEX treatment resulted in complete recovery of transendothelial electrical resistance and hydraulic conductivity 1 day after injury, compared with 3 days for vehicle-treated injured cultures. Administration of RU486 (mifepristone) inhibited effects of DEX, confirming that barrier restoration was mediated by glucocorticoid receptor signaling. Potentiated recovery with DEX treatment was accompanied by stronger zonula occludens (ZO)-1 tight junction immunostaining and expression, suggesting that increased ZO-1 expression was a structural correlate to BBB recovery after blast. Interestingly, augmented ZO-1 protein expression was associated with specific upregulation of the α+ isoform but not the α isoform. This is the first study to provide a mechanistic basis for potentiated functional recovery of an in vitro BBB model because of glucocorticoid treatment after primary blast injury.  相似文献   
5.
6.
7.
8.

Background

The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.

Objectives

The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.

Methods

PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.

Results

Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).

Conclusions

In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550)  相似文献   
9.
10.
In May 2017, the Health and Environmental Sciences Institute's Genetic Toxicology Technical Committee hosted a workshop to discuss whether mode of action (MOA) investigation is enhanced through the application of the adverse outcome pathway (AOP) framework. As AOPs are a relatively new approach in genetic toxicology, this report describes how AOPs could be harnessed to advance MOA analysis of genotoxicity pathways using five example case studies. Each of these genetic toxicology AOPs proposed for further development includes the relevant molecular initiating events, key events, and adverse outcomes (AOs), identification and/or further development of the appropriate assays to link an agent to these events, and discussion regarding the biological plausibility of the proposed AOP. A key difference between these proposed genetic toxicology AOPs versus traditional AOPs is that the AO is a genetic toxicology endpoint of potential significance in risk characterization, in contrast to an adverse state of an organism or a population. The first two detailed case studies describe provisional AOPs for aurora kinase inhibition and tubulin binding, leading to the common AO of aneuploidy. The remaining three case studies highlight provisional AOPs that lead to chromosome breakage or mutation via indirect DNA interaction (inhibition of topoisomerase II, production of cellular reactive oxygen species, and inhibition of DNA synthesis). These case studies serve as starting points for genotoxicity AOPs that could ultimately be published and utilized by the broader toxicology community and illustrate the practical considerations and evidence required to formalize such AOPs so that they may be applied to genetic toxicity evaluation schemes. Environ. Mol. Mutagen. 61:114–134, 2020. © 2019 Wiley Periodicals, Inc.  相似文献   
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