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   35984篇
  免费   1936篇
  国内免费   152篇
耳鼻咽喉   362篇
儿科学   815篇
妇产科学   659篇
基础医学   6625篇
口腔科学   779篇
临床医学   2939篇
内科学   6896篇
皮肤病学   945篇
神经病学   3825篇
特种医学   1472篇
外科学   4781篇
综合类   180篇
一般理论   14篇
预防医学   1789篇
眼科学   1122篇
药学   2446篇
中国医学   21篇
肿瘤学   2402篇
  2022年   183篇
  2021年   377篇
  2020年   322篇
  2019年   518篇
  2018年   602篇
  2017年   462篇
  2016年   610篇
  2015年   708篇
  2014年   826篇
  2013年   1281篇
  2012年   1772篇
  2011年   1879篇
  2010年   1249篇
  2009年   1192篇
  2008年   2014篇
  2007年   2066篇
  2006年   1923篇
  2005年   2035篇
  2004年   1922篇
  2003年   1888篇
  2002年   1928篇
  2001年   430篇
  2000年   363篇
  1999年   479篇
  1998年   537篇
  1997年   434篇
  1996年   393篇
  1995年   369篇
  1994年   310篇
  1993年   275篇
  1992年   264篇
  1991年   270篇
  1990年   234篇
  1989年   223篇
  1988年   223篇
  1987年   187篇
  1986年   177篇
  1985年   214篇
  1984年   227篇
  1983年   185篇
  1982年   226篇
  1981年   194篇
  1979年   160篇
  1978年   168篇
  1933年   171篇
  1932年   181篇
  1931年   167篇
  1930年   169篇
  1928年   164篇
  1926年   159篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
Forced-choice testing provides evidence of malingering.   总被引:1,自引:0,他引:1  
Assessment of motivation using forced-choice testing is described and illustrated with case reports. Two injured workers with protracted disability complained of numbness and loss of sensation in their fingers. Each patient received a forced-choice, multiple-choice finger graphesthesia test, with a 0.5 probability of guessing correctly on each item. Both patients performed significantly below the chance level, indicating that they had deliberately provided wrong answers. One patient did not exaggerate until the difficulty level of the task was enhanced. Forced-choice testing, particularly with enhancement of difficulty levels, is proposed as a specific measure to detect faked poor performance. Identification of malingering reduces the risk of iatrogenic damage. The subjective complaints of malingerers must be viewed with skepticism.  相似文献   
94.
Two recently discovered genes, the recombination activating genes 1 and 2 (RAG-1 and RAG-2), are necessary to perform variable (V), diversity (D), and joining (J) recombination. They synergistically activate VDJ recombination to generate immunocompetent lymphocytes. Disruption of either gene results in a maturation arrest at a very early B and T cell progenitor stage. Expression and downregulation of RAG's are closely associated with interleukin 7, sIgM and TCR-CD3 complex, respectively. Assessment of RAG mRNA expression is a valuable marker in identifying the genotypic maturation status of leukemias and lymphomas. Persistent RAG expression in otherwise mature lymphoid proliferations may explain puzzling biological and clinical observations such as multiple rearrangements in lymphomas with a mature phenotype. Lack of RAG expression in Hodgkin's disease with abundant Reed-Stern-berg cells is consistent with a mature phenotype of the latter. Availability of a anti-RAG-1 monoclonal antibody in the near future will facilitate RAG analysis of lymphomas.  相似文献   
95.
96.
97.
We investigated non-rapid eye movement (non-REM) sleep in patients with newly diagnosed Parkinson's disease (PD) who had never previously received dopaminergic medication. There were no significant differences in the conventional sleep parameters between de novo patients with PD and a healthy control group, but the length of stage 1 sleep and the number of awakenings increased significantly upon administration of dopaminergic drugs. Analyzing the quantitative electroencephalogram (EEG), we observed a significant reduction in the low-delta frequency range and a nonsignificant increase in the sigma frequency range in de novo patients with PD. The dopaminergic medication also nonsignificantly reduced the low-delta and sigma frequencies, the latter to the level of the controls. Possible mechanisms that may account for the observed differences are discussed. It is suggested that Parkinson's disease as well as the application of dopaminergic drugs exerts a desynchronizing effect on the sleep EEG that is reflected in a disruption of sleep continuity.  相似文献   
98.
Besides of four pica cases (eating of dirt, paper, cotton, oakum, sand, lime, chalk) the authors report on a girl with trichophagia. The treatment of choice in pica consists in a sufficient supply of iron. The authors suggest that the intravenously administered iron acts on some centers of the central nervous system.  相似文献   
99.
This study showed that, in chickens, the negative effects of phytate-phosphorus in a low inorganic phosphorus diet could be completely reversed through the additive effects of reduced dietary calcium and increased cholecalciferol. In the future, perhaps greater reliance on more readily available plant phosphorus sources may be instituted in developing countries, where cheap sources of inorganic phosphorus are difficult to obtain.  相似文献   
100.
Summary Thoracoscopic surgery is decidedly expanded by the ability to perform pulmonary wedge resections of the lung by using the Endo-GIA-stapler. In addition to thoracoscopic biopsies, since July 1991 we have carried out wedge resections in 12 patients suffering from spontaneous pneumothorax (nine) or peripheral bronchial carcinoma (three). Postoperatively one air fistula persisted over 9 days. The chest tube was removed within 48 h in all other patients. There was no other major complication. The postoperative hospitalization period lasted 4.6 days (1–9 days). Operating time was 44 min (30–70 min). The benefit for the patient consists in the little-impaired breathing mechanics, the short hospital stay, and the favorable cosmetic result.  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