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   2998898篇
  免费   218072篇
  国内免费   5120篇
耳鼻咽喉   41202篇
儿科学   98982篇
妇产科学   81675篇
基础医学   439246篇
口腔科学   83683篇
临床医学   272133篇
内科学   577011篇
皮肤病学   66657篇
神经病学   237437篇
特种医学   113092篇
外国民族医学   768篇
外科学   449587篇
综合类   64901篇
现状与发展   12篇
一般理论   1162篇
预防医学   236350篇
眼科学   70068篇
药学   221693篇
  13篇
中国医学   5876篇
肿瘤学   160542篇
  2019年   24048篇
  2018年   33368篇
  2017年   25305篇
  2016年   28478篇
  2015年   32039篇
  2014年   45137篇
  2013年   68229篇
  2012年   92962篇
  2011年   98940篇
  2010年   59014篇
  2009年   55655篇
  2008年   92900篇
  2007年   98874篇
  2006年   99848篇
  2005年   96788篇
  2004年   93020篇
  2003年   89529篇
  2002年   86693篇
  2001年   135714篇
  2000年   139288篇
  1999年   117227篇
  1998年   34124篇
  1997年   30144篇
  1996年   30364篇
  1995年   28872篇
  1994年   26647篇
  1993年   25106篇
  1992年   91664篇
  1991年   89603篇
  1990年   87620篇
  1989年   84405篇
  1988年   77469篇
  1987年   76474篇
  1986年   71610篇
  1985年   68870篇
  1984年   51458篇
  1983年   43703篇
  1982年   26147篇
  1979年   47464篇
  1978年   34055篇
  1977年   28448篇
  1976年   27248篇
  1975年   29050篇
  1974年   35045篇
  1973年   33391篇
  1972年   31195篇
  1971年   29522篇
  1970年   27202篇
  1969年   25846篇
  1968年   23771篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
This paper critically examines the pharmacological provocation and treatment of panic disorder. An analysis of research findings on how panic attacks are induced indicates that there are psychological and non specific factors that may mediate biochemical etiological models, and these individual differences need to be investigated further. This has important implications for the psychopharmacological management of panic. A review of studies on treating panic disorder with imipramine and alprazolam emphasizes the importance of several non specific factors that include the role of self-directed in vivo exposure and changes in dysphoria and self-efficacy (subjective beliefs regarding personal competency) in predicting outcome. It is recommended that any treatment of panic-related disorders include self-directed, in vivo exposure.  相似文献   
942.
In newly diagnosed adult patients with epilepsy followed prospectively on monotherapy, carbamazepine and phenytoin were associated with a fall in plasma uric acid, but sodium valproate and phenobarbitone were associated with a rise in plasma uric acid. The mechanisms and significance of these findings are discussed.  相似文献   
943.
We experienced one necropsy case of brainstem encephalitis of Iizuka type (BSE) and one necropsy case of the brain-stem syndrome (BSS) of typical neuro-Beh?et's disease, and compared them clinically and neuropathologically. Clinically both of these cases showed chronic progressive mental disturbance, pseudobulbar paresis, spastic tetraparesis, cerebrospinal fluid pleocytosis, increased protein, and brainstem atrophy observed by X-CT. Neuropathologically, irregular, boundary-indistinct demyelinating lesions and obsolete softening lesions were sporadically found, associated with perivascular lymphocytic infiltration and gliosis centering on the brainstem. In this way, both cases were similar in many points except for the presence or absence of cutaneo-muco-ocular signs specific for Beh?et's disease. Also BSE and BSS reports in the literature showed that both diseases were similar not only in clinical findings consisting of mental disturbance and brainstem signs but also in neuropathological findings with similar topographical distribution of the same histopathological changes, including the variations and diversity of these characteristics. Especially of much interest is their similarity in characteristic mental disturbance. In discriminating BSE from multiple sclerosis and other diseases with exclusive involvement of the brainstem, it is important to understand their clinical characteristics. The characteristic mental disturbance includes damage to memory and sentiment, a change in personality, and lowering in spontaneity, but calculation ability and orientation are comparatively preserved. Of course the similarity in clinical and neuropathological findings does not necessarily mean the identical etiopathogenesis. However, it is possible to consider that neuro-Beh?et's disease (syndrome) may form a wide spectrum with BSE and typical neuro-Beh?et's disease at the both ends, regarding the time and spatial diversity of the appearance of cutaneo-muco-ocular signs.  相似文献   
944.
A survey of research activity of American academic child psychiatrists was completed in February, 1989. The survey demonstrated an increase in research activity since the 1983 report in the Current Status of Child Psychiatry. A definition of a researcher was derived from a study of internists and general psychiatrists and applied to the 488 respondents (78.5% of sample), and it was found that males outnumber females and that researchers contribute significantly more to the literature and education than nonresearchers. Early research exposure and mentoring are important influences on a research career. Recommendations by researchers for future training of researchers are presented. Periodic surveys are encouraged.  相似文献   
945.
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   
946.
947.
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   
948.
949.
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   
950.
Anesthetic management of the morbidly obese patient   总被引:1,自引:0,他引:1  
  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