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   211099篇
  免费   15301篇
  国内免费   749篇
耳鼻咽喉   2294篇
儿科学   5506篇
妇产科学   4312篇
基础医学   27219篇
口腔科学   4603篇
临床医学   20106篇
内科学   45034篇
皮肤病学   2761篇
神经病学   20381篇
特种医学   6976篇
外国民族医学   13篇
外科学   33003篇
综合类   3426篇
现状与发展   2篇
一般理论   294篇
预防医学   19163篇
眼科学   4385篇
药学   14457篇
  3篇
中国医学   376篇
肿瘤学   12835篇
  2023年   847篇
  2022年   1408篇
  2021年   3459篇
  2020年   2110篇
  2019年   3398篇
  2018年   3984篇
  2017年   3220篇
  2016年   3416篇
  2015年   4075篇
  2014年   6107篇
  2013年   8835篇
  2012年   13151篇
  2011年   14345篇
  2010年   8105篇
  2009年   7332篇
  2008年   13617篇
  2007年   14461篇
  2006年   13954篇
  2005年   14434篇
  2004年   13842篇
  2003年   12935篇
  2002年   12473篇
  2001年   1913篇
  2000年   1485篇
  1999年   2079篇
  1998年   2837篇
  1997年   2443篇
  1996年   2217篇
  1995年   1961篇
  1994年   1760篇
  1993年   1661篇
  1992年   1227篇
  1991年   1169篇
  1990年   1076篇
  1989年   974篇
  1988年   1024篇
  1987年   1038篇
  1986年   1016篇
  1985年   1106篇
  1984年   1489篇
  1983年   1469篇
  1982年   1822篇
  1981年   1646篇
  1980年   1565篇
  1979年   822篇
  1978年   965篇
  1977年   942篇
  1976年   842篇
  1975年   695篇
  1974年   674篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Immediate reconstruction of more than 1000 breasts was performed on high-risk patients on whom a prophylactic mastectomy was done. The mastectomy removes as much breast tissue as possible while leaving sufficient skin, and possibly the nipple-areola complex, to enable immediate reconstruction. The creation of symmetrical, well-balanced muscle pockets for the implant is the most important factor in producing satisfactory results in these cases.  相似文献   
42.
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   
43.
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   
44.
45.
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   
46.
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   
47.
48.
49.
Anorectal function in the solitary rectal ulcer syndrome   总被引:8,自引:6,他引:2  
The anorectal function of nine patients with solitary rectal ulcer syndrome (SRUS) (5 F: 4 M, median age, 27 (range, 19–41 years) and nine control subjects (5 F: 4 M, median age, 47 (35–66)P<0.01) has been investigated by a new technique that radiologically visualizes the anorectum during voiding of a semisolid contrast medium, while simultaneously measuring intrarectal pressure and anal sphincter EMG activity. A degree of rectal prolapse was demonstrated in eight of the SRUS patients; six of these lesions were clinically occult. Abnormal failure of the anal sphincter to relax on voiding was present in seven of the SRUS patients. These abnormalities resulted in the SRUS patients requiring a greater increase in intrarectal pressure (median, 100 cm water) to void than the control subjects (median, 65 cm water,P<0.01). This combination of high intrarectal pressure and rectal prolapse during straining seems to be the cause of SRUS This work was supported by a grant from the Medical Research Council.  相似文献   
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