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   296240篇
  免费   17229篇
  国内免费   414篇
耳鼻咽喉   4205篇
儿科学   10294篇
妇产科学   10243篇
基础医学   44970篇
口腔科学   7497篇
临床医学   24166篇
内科学   55799篇
皮肤病学   6310篇
神经病学   21027篇
特种医学   11611篇
外国民族医学   43篇
外科学   46666篇
综合类   7766篇
现状与发展   1篇
一般理论   160篇
预防医学   19911篇
眼科学   6943篇
药学   20872篇
中国医学   787篇
肿瘤学   14612篇
  2018年   3612篇
  2017年   2651篇
  2016年   3073篇
  2015年   3494篇
  2014年   4577篇
  2013年   7207篇
  2012年   9064篇
  2011年   9457篇
  2010年   6127篇
  2009年   5543篇
  2008年   8680篇
  2007年   9521篇
  2006年   9349篇
  2005年   8951篇
  2004年   8658篇
  2003年   8162篇
  2002年   7755篇
  2001年   13320篇
  2000年   13648篇
  1999年   11416篇
  1998年   3025篇
  1997年   2788篇
  1996年   2633篇
  1995年   2545篇
  1994年   2343篇
  1992年   8313篇
  1991年   8453篇
  1990年   8262篇
  1989年   8075篇
  1988年   7313篇
  1987年   7075篇
  1986年   6722篇
  1985年   6516篇
  1984年   4760篇
  1983年   4118篇
  1982年   2469篇
  1979年   4430篇
  1978年   3230篇
  1977年   2731篇
  1976年   2503篇
  1975年   2835篇
  1974年   3354篇
  1973年   3363篇
  1972年   3118篇
  1971年   2951篇
  1970年   2840篇
  1969年   2582篇
  1968年   2539篇
  1967年   2374篇
  1966年   2266篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
93.
94.
95.
96.
The efficiency of the Racal Airstream helmet respirator in improving peak expiratory flow rates (PEFR) and symptoms (dyspnea, wheezing, and cough) in aluminum potroom workers with respiratory complaints was assessed in 19 workers. Peak expiratory flow readings and symptom recording from a 2-week working period with use of the respirator were compared with a period when the 3M 9906 disposable mask was used. The study was designed as a randomized, parallel, cross-over study with five or six daily measurements of PEFR and daily symptom recording. A significant number of workers (15) had a higher mean peak flow in the helmet period than in the nonhelmet period (p less than 0.01); symptoms did not improve significantly in the helmet period. Objective evidence of respiratory protection was observed for the group of workers as a whole, but the effect on symptoms as well as individual effect on peak flow was minor in the majority of the workers.  相似文献   
97.
A microfluorometric method was used to determine the nuclear DNA content in the nasopharyngeal carcinomas (NPC) of 25 patients treated before 1983. Eleven patients are still alive with no evidence of disease (NED), while the rest died of their disease (DOD). All of the patients received a cycle of radiotherapy, while some also received chemotherapy or neck dissections. The neoplastic cells studied were taken from the original biopsy blocks, deparaffinized, isolated by enzymatic treatment and mechanical fragmentation, and then Feulgen-stained. The cytofluorometric measurement was carried out by a microphotometer equipped for fluorescence excitation and connected to a computer. This method allowed us to construct a histogram of the DNA content in the neoplastic cells. Different neoplastic classes were identified and represent the heteroclonality of the tumor, which can be expressed by the heteroclonality index (HCT). From the collected data it appears that the NED patients all had a low HTC (less than 1) and only 7 of the DOD patients had low HTCs (less than 1). Six of the DOD patients with a low HTC were in advanced stages of their tumor at the time of diagnosis, while the remaining patient did not complete his treatment. Our results show that the DNA analysis of the NPC cell population may offer a useful tool in predicting the biological behavior of this tumor and also improving its treatment.  相似文献   
98.
99.
Serum digoxin-like factor was detected in infants of diabetic mothers who were insulin-dependent or diet controlled. No statistical difference was found between the serum digoxin-like factor levels of the infants of diabetic mothers and the controls.  相似文献   
100.
In a single patient suffering from a major depressive episode with melancholia (DSM-III), both severe psychomotor symptoms, such as stupor and mutism, and mood disturbances could be abolished completely and promptly by administration of the benzodiazepine lorazepam. Remission of symptoms was entirely and immediately reversed by the benzodiazepine antagonist Ro 15-1788. These drug effects were constantly reproducible. Possible mechanisms of action and the influence of GABAergic neurotransmission on affective and psychomotor state are discussed.  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