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   3029339篇
  免费   239249篇
  国内免费   6166篇
耳鼻咽喉   43176篇
儿科学   96258篇
妇产科学   82137篇
基础医学   429314篇
口腔科学   87790篇
临床医学   277719篇
内科学   586629篇
皮肤病学   63874篇
神经病学   251319篇
特种医学   119814篇
外国民族医学   1132篇
外科学   455510篇
综合类   72894篇
现状与发展   1篇
一般理论   1311篇
预防医学   246297篇
眼科学   71672篇
药学   224440篇
  8篇
中国医学   5741篇
肿瘤学   157718篇
  2018年   31472篇
  2017年   24211篇
  2016年   27011篇
  2015年   30378篇
  2014年   43428篇
  2013年   66514篇
  2012年   89049篇
  2011年   94095篇
  2010年   55730篇
  2009年   53081篇
  2008年   88930篇
  2007年   94620篇
  2006年   95546篇
  2005年   92881篇
  2004年   89756篇
  2003年   86493篇
  2002年   84765篇
  2001年   138161篇
  2000年   143002篇
  1999年   120716篇
  1998年   35235篇
  1997年   31926篇
  1996年   31559篇
  1995年   30589篇
  1994年   28723篇
  1993年   26703篇
  1992年   97553篇
  1991年   94606篇
  1990年   91710篇
  1989年   88360篇
  1988年   81690篇
  1987年   80834篇
  1986年   76372篇
  1985年   73246篇
  1984年   55534篇
  1983年   47404篇
  1982年   28930篇
  1981年   25819篇
  1979年   52191篇
  1978年   36886篇
  1977年   31219篇
  1976年   29412篇
  1975年   30895篇
  1974年   38062篇
  1973年   36231篇
  1972年   33800篇
  1971年   31372篇
  1970年   29312篇
  1969年   27331篇
  1968年   24979篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Electrocardiograms were evaluated in 39 children and adolescents before and after the clinical use of imipramine and desipramine. The average increase in PR interval was 0.01 seconds. The PR interval increased by 0.02 seconds in 11 subjects, and a new first-degree atrioventricular block developed in two subjects. These changes were not related to the choice between imipramine and desipramine, the dose, or the method of administration. An increase in PR interval by 0.02 seconds or more did correlate with having an abnormality disclosed on a pretreatment electrocardiogram. The average increase in PR interval was 0.007 seconds for subjects with normal baseline electrocardiograms and 0.019 seconds for subjects with conduction and nonconduction abnormalities disclosed in baseline tracings. None of the electrocardiogram changes resulted in adverse clinical consequences.  相似文献   
962.
Overanxious disorder: a review of its taxonomic properties   总被引:1,自引:0,他引:1  
The taxonomic properties of overanxious disorder are reviewed using the diagnostic criteria and other features listed in the DSM-III-R manual as a template. The data suggest that overanxious disorder is only a modestly reliable, distinct and valid taxon, and that adjustments to the diagnostic items and criteria and improved sources and methods of data capture are needed. Such changes should be on the basis of empirical data. Since these data are not yet extant, better psychometric-type studies are needed, coupled to assessments of validity. Recently, there has been a distinct increase in number and quality of studies. Although some adjustments are needed, to alter overanxious disorder too much in DSM-IV could make past studies of doubtful relevance and could force a fresh start instead of building on current knowledge.  相似文献   
963.
Effect of respiratory training with a mouth-nose-mask in tetraplegics   总被引:1,自引:0,他引:1  
Ten tetraplegics, 8 males and 2 females, with a median age of 32 years participated in a scheduled 6 weeks training programme with a respiratory muscle training mouth-nose-mask (RMT-mask) with a fixed expiratory and an increasing inspiratory resistance set by the tetraplegic in accordance to his/her increasing ability during the training period. During the 6 weeks the tetraplegics required to use the RMT-mask for 15 minutes three times a day. Before and after each training session they measured peak flow (PEF). Lung volumes, ventilatory and diffusion capacity were measured before and after the 6 weeks training period. The training resulted only in a significant change in the PEF, which increased with 11% from 371 l/min before to 412 l/min in average after the 6 weeks of training (p less than 0.025). This statistically significant increase was confirmed by the measurements of PEF performed by the tetraplegics themselves during the training period. In addition there was an increase in PEF from before to immediately after each 15 minutes training session, this trend reached statistically significance (p less than 0.025) in the third '2 weeks period'. These results might indicate a possibility of improving the tetraplegics ability to cough by use of a simple RMT-mask, which in turn might prevent certain lung complications including pneumonia, and atelectasia.  相似文献   
964.
We report a case of mild visuo-spatial neglect consequent upon right-hemisphere stroke. At the time of testing, the patient had a complete left visual field deficit but only a very slight left hemiparesis. Under conventional testing conditions, line bisection performed with the right hand showed more severe left neglect than when performed with the left hand. This pattern of performance could, however, be modified, both quantitatively and qualitatively, by changing the starting position of the patient's hand when bisecting horizontal lines. The results suggest that spatio-motor cueing has a more profound effect upon task performance than does differential hemispheric activation per se. We also provide a demonstration that, in a normal subject, the starting position of the hand is likewise a crucial determinant of task performance. In this case, however, there is also an interaction between the hand (and hence hemisphere) deployed and the position of that hand in space.  相似文献   
965.
966.
In a vertically slotted 0.022 X 0.028 inch edgewise system, the use of a two-dimensional ribbon arch--0.022 X 0.016 inch from lateral incisor to lateral incisor and 0.016 X 0.022 inch from the canine to the molars--plus an uprighting spring on the canine maintained incisor position while unilaterally protracting a molar-premolar unit by means of sliding mechanics. Five degrees of labial crown torque was placed in the incisor portion of the wire and the uprighting spring exerted a force of 200 to 250 g. The intra-arch force applied to protract the molar--premolar unit was 300 to 350 g.  相似文献   
967.
The present study evaluated the use of psychologic measures, in particular, the relatively new Million Behavioral Health Inventory (MBHI), in predicting change in physical function of chronic low back pain patients undergoing a functional restoration program. The first 134 consecutive patients completing this program were assessed. Results demonstrated that various clinical scales of the MBHI were predictive of improvement in physical function. In addition, various scales enabled discrimination between patients who completed the program and those who prematurely dropped out. Although this inventory shows promise in helping to predict response to treatment, no single psychologic test can reliably be used as the sole predictor in clinical cases.  相似文献   
968.
Of 299 patients who presented with superficial bladder cancer (Ta, T1), 60 were treated by intravesical chemotherapy (Epodyl, methotrexate or mitomycin C). The rate of tumour progression to muscle invasion or metastases was identical for each intravesical regime. There was no evidence that mitomycin C promoted tumour progression. Carcinoma in situ in non-tumour-bearing urothelium was the most significant predictive factor for progression to muscle invasion or metastases.  相似文献   
969.
Anesthetic management of the morbidly obese patient   总被引:1,自引:0,他引:1  
  相似文献   
970.
The expression of ras oncogene in normal and pathological liver disease   总被引:1,自引:0,他引:1  
Activation of the ras oncogene is associated with overproduction of the normal gene product (p21). Ninety one paraffin-embedded specimens were used to map the distribution of the normal form of p21 in normal, inflamed, cirrhotic and carcinomatous liver parenchyma. Monoclonal antibodies (Mo-RAP) were raised against the normal form of the ras-oncogene product and histological sections were stained by the peroxidase-antiperoxidase technique. Normal, inflamed and cirrhotic liver showed either minimal or moderate cytoplasmic staining. By contrast primary (n = 13) and secondary (n = 41) liver carcinomas exhibited intense staining. The differential pattern observed in p21 distribution could have useful clinical applications.  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