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   357198篇
  免费   45155篇
  国内免费   3007篇
耳鼻咽喉   7221篇
儿科学   10747篇
妇产科学   6613篇
基础医学   30650篇
口腔科学   6007篇
临床医学   45765篇
内科学   90227篇
皮肤病学   10116篇
神经病学   34734篇
特种医学   13176篇
外国民族医学   14篇
外科学   72399篇
综合类   3668篇
现状与发展   74篇
一般理论   294篇
预防医学   25929篇
眼科学   7613篇
药学   15613篇
  1篇
中国医学   384篇
肿瘤学   24115篇
  2023年   5449篇
  2022年   2547篇
  2021年   6409篇
  2020年   7875篇
  2019年   5478篇
  2018年   11074篇
  2017年   10278篇
  2016年   11455篇
  2015年   12175篇
  2014年   21017篇
  2013年   23858篇
  2012年   18489篇
  2011年   19693篇
  2010年   18097篇
  2009年   20970篇
  2008年   19295篇
  2007年   18527篇
  2006年   20297篇
  2005年   18224篇
  2004年   16894篇
  2003年   15042篇
  2002年   14593篇
  2001年   5523篇
  2000年   4349篇
  1999年   5141篇
  1998年   6305篇
  1997年   5750篇
  1996年   5393篇
  1995年   4983篇
  1994年   3605篇
  1993年   3151篇
  1992年   2557篇
  1991年   2490篇
  1990年   2068篇
  1989年   2095篇
  1988年   1995篇
  1987年   1836篇
  1986年   1847篇
  1985年   1765篇
  1984年   2026篇
  1983年   1961篇
  1982年   2309篇
  1981年   2019篇
  1980年   1901篇
  1979年   1103篇
  1978年   1283篇
  1977年   1297篇
  1976年   1061篇
  1975年   955篇
  1974年   885篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
An educational intervention was developed to improve family practice residents' ability to obtain useful information from pharmaceutical representatives. The curriculum is based on the traditional one-on-one drug detail. The objectives are to develop residents' skills in controlling the interview, promote skills for critically analyzing drug-promotional material, and discuss ethical issues. The contents include an assessment tool, suggested readings, and interview questions with rationale. After 5 years, residents' confidence in all areas of the curriculum improved significantly.  相似文献   
44.
Summary Contradictory immunohistochemical data have been reported on the localization of N-acetylaspartylglutamate in the rat forebrain, using different carbodiimide fixation protocols and antibody purification methods. In one case, N-acetylaspartylglutamate immunoreactivity was observed in apparent interneurons throughout all allocortical and isocortical regions, suggesting possible colocalization with GABA. In another case, strong immunoreactivity was observed in numerous pyramidal cells in neocortex and hippocampus, suggesting colocalization with glutamate or aspartate. Reconciling these disparate findings is crucial to understanding the role of N-acetylaspartylglutamate in nervous system function. Antibodies to N-acetylaspartylglutamate and a structurally related molecule, N-acetylaspartate, were purified in stages, and their cross-reactivities with protein conjugates of N-acetylaspartylglutamate and N-acetylaspartate were monitored at each stage by solidphase immunoassay. Reduction of the cross-reactivity of the anti-N-acetylaspartylglutamate antibodies to N-acetylaspartateprotein conjugates to about 1% eliminated significant staining of most pyramidal neurons in the rat forebrain. Utilizing highly purified antibodies, the distributions of N-acetylaspartylglutamate and N-acetylaspartate were examined in several major telencephalic and diencephalic regions of the rat, and were found to be distinct. N-acetylaspartylglutamate-immunoreactivity was observed in specific neuronal populations, including many groups thought to use GABA as a neurotransmitter. Among these were the globus pallidus, ventral pallidum, entopeducular nucleus, thalamic reticular nucleus, and scattered non-pyramidal neurons in all layers of isocortex and allocortex. N-acetylaspartate-immunoreactivity was more broadly distributed than N-acetylaspartylglutamate-immunoreactivity in the rat forebrain, appearing strongest in many pyramidal neurons. Although N-acetylaspartate-immunoreactivity was found in most neurons, it exhibited a great range of intensities between different neuronal types.  相似文献   
45.
46.
The writers examine the course of Greek ophthalmology from the Hellenistic period to the foundation of the first universities (19th century). In particular, the study refers to Galen, Antyllus, the Byzantine doctors Oribasius, Aetius of Ameda, Paul of Aegina, Alexander of Tralles, Nonnus Theophanes, Theophilus Protospatharius, Michael Psellos, Meletius Monachus, Nemesius bishop of Emeses and John Actuarius. The practice of empirical ophthalmology during the Ottoman domination of Greece is also examined, as is the earliest available evidence of modern Greek ophthalmological knowledge, deriving from the Ionian Islands.  相似文献   
47.
Sixty-three mallards were fed one of ten poly(methyl methacrylate) based synthetic grit formulations containing varying concentrations of a proposed wildlife contraceptive (nicarbazin), plasticizer (acetyl tributylcitrate) and/or cross-linking agent (1,4-butanediol diacrylate). Release characteristics of the contraceptive agent were monitored for the purpose of developing a contraceptive formulation for control of pest waterfowl in urban settings. The addition of plasticizer increased the erosion rate (t(1/2)=0.97-2.85 days), cross-linking the polymer matrix slightly decreased the erosion rate (t(1/2)=4.45-5.05 days) and increasing the concentration of the contraceptive agent increased the erosion rate (t(1/2)=3.3 and 9.9 days at 60% and 7.5% active ingredient, respectively). The larger and smaller grit pieces had longer half lives at 11.0 and 11.6 days, respectively while the mid sized grit had a half life of 4.95 days. Control grit had a half life of 12.7 days based on weight loss. Analysis of blood and feces for monitoring release from the grit and approximate indirect plasma levels of the active ingredient proved feasible.  相似文献   
48.
49.
50.
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