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   24473篇
  免费   1576篇
  国内免费   176篇
耳鼻咽喉   244篇
儿科学   530篇
妇产科学   467篇
基础医学   3661篇
口腔科学   285篇
临床医学   2319篇
内科学   6111篇
皮肤病学   364篇
神经病学   2114篇
特种医学   1075篇
外国民族医学   8篇
外科学   4225篇
综合类   68篇
一般理论   4篇
预防医学   1331篇
眼科学   213篇
药学   1351篇
中国医学   42篇
肿瘤学   1813篇
  2023年   120篇
  2022年   143篇
  2021年   610篇
  2020年   365篇
  2019年   589篇
  2018年   695篇
  2017年   464篇
  2016年   562篇
  2015年   714篇
  2014年   939篇
  2013年   1209篇
  2012年   1925篇
  2011年   1896篇
  2010年   1097篇
  2009年   1108篇
  2008年   1680篇
  2007年   1699篇
  2006年   1659篇
  2005年   1704篇
  2004年   1576篇
  2003年   1481篇
  2002年   1395篇
  2001年   206篇
  2000年   155篇
  1999年   220篇
  1998年   265篇
  1997年   231篇
  1996年   190篇
  1995年   159篇
  1994年   117篇
  1993年   142篇
  1992年   106篇
  1991年   83篇
  1990年   79篇
  1989年   54篇
  1988年   58篇
  1987年   43篇
  1986年   51篇
  1985年   46篇
  1984年   40篇
  1983年   49篇
  1982年   41篇
  1981年   48篇
  1980年   37篇
  1979年   21篇
  1978年   16篇
  1977年   15篇
  1976年   14篇
  1975年   18篇
  1972年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Animal and human studies suggest fish oil and green tea may have protective effect on prostate cancer. Fatty acid synthase (FAS) has been hypothesized to be linked to chemoprotective effects of both compounds. This study evaluated the independent and joint effects of fish oil (FO) and green tea supplement (epigallocatechin-3-gallate, EGCG) on FAS and Ki-67 levels in prostate tissue. Through a double-blinded, randomized controlled trial with 2 × 2 factorial design, 89 men scheduled for repeat prostate biopsy following an initial negative prostate biopsy were randomized into either FO alone (1.9 g DHA + EPA/day), EGCG alone (600 mg/day), a combination of FO and EGCG, or placebo. We used linear mixed-effects models to test the differences of prostate tissue FAS and Ki-67 by immunohistochemistry between pre- and post-intervention within each group, as well as between treatment groups. Results did not show significant difference among treatment groups in pre-to-post-intervention changes of FAS (P = 0.69) or Ki-67 (P = 0.26). Comparing placebo group with any of the treatment groups, we did not find significant difference in FAS or Ki-67 changes (all P > 0.05). Results indicate FO or EGCG supplementation for a short duration may not be sufficient to produce biologically meaningful changes in FAS or Ki-67 levels in prostate tissue.  相似文献   
3.
4.
5.
Melatonin receptors play important roles in the regulation of circadian and seasonal rhythms, sleep, retinal functions, the immune system, depression, and type 2 diabetes development. Melatonin receptors are approved drug targets for insomnia, non‐24‐hour sleep‐wake disorders, and major depressive disorders. In mammals, two melatonin receptors (MTRs) exist, MT1 and MT2, belonging to the G protein‐coupled receptor (GPCR) superfamily. Similar to most other GPCRs, reliable antibodies recognizing melatonin receptors proved to be difficult to obtain. Here, we describe the development of the first monoclonal antibodies (mABs) for mouse MT1 and MT2. Purified antibodies were extensively characterized for specific reactivity with mouse, rat, and human MT1 and MT2 by Western blot, immunoprecipitation, immunofluorescence, and proximity ligation assay. Several mABs were specific for either mouse MT1 or MT2. None of the mABs cross‐reacted with rat MTRs, and some were able to react with human MTRs. The specificity of the selected mABs was validated by immunofluorescence microscopy in three established locations (retina, suprachiasmatic nuclei, pituitary gland) for MTR expression in mice using MTR‐KO mice as control. MT2 expression was not detected in mouse insulinoma MIN6 cells or pancreatic beta‐cells. Collectively, we report the first monoclonal antibodies recognizing recombinant and native mouse melatonin receptors that will be valuable tools for future studies.  相似文献   
6.
7.
Magnetic resonance elastography aims to non-invasively and remotely characterize the mechanical properties of living tissues. To quantitatively and regionally map the shear viscoelastic moduli in vivo, the technique must achieve proper mechanical excitation throughout the targeted tissues. Although it is straightforward, ante manibus, in close organs such as the liver or the breast, which practitioners clinically palpate already, it is somewhat fortunately highly challenging to trick the natural protective barriers of remote organs such as the brain. So far, mechanical waves have been induced in the latter by shaking the surrounding cranial bones. Here, the skull was circumvented by guiding pressure waves inside the subject's buccal cavity so mechanical waves could propagate from within through the brainstem up to the brain. Repeatable, reproducible and robust displacement fields were recorded in phantoms and in vivo by magnetic resonance elastography with guided pressure waves such that quantitative mechanical outcomes were extracted in the human brain.  相似文献   
8.
9.
10.
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