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   1343022篇
  免费   112886篇
  国内免费   6431篇
耳鼻咽喉   16754篇
儿科学   43113篇
妇产科学   36754篇
基础医学   184225篇
口腔科学   36398篇
临床医学   121036篇
内科学   279346篇
皮肤病学   32162篇
神经病学   110829篇
特种医学   55715篇
外国民族医学   274篇
外科学   211051篇
综合类   31611篇
现状与发展   2篇
一般理论   418篇
预防医学   106940篇
眼科学   28251篇
药学   93944篇
  5篇
中国医学   2251篇
肿瘤学   71260篇
  2018年   13510篇
  2017年   10739篇
  2016年   12932篇
  2015年   14470篇
  2014年   20167篇
  2013年   29951篇
  2012年   36577篇
  2011年   39248篇
  2010年   24609篇
  2009年   24132篇
  2008年   36643篇
  2007年   39035篇
  2006年   40149篇
  2005年   38742篇
  2004年   36919篇
  2003年   35986篇
  2002年   34010篇
  2001年   66129篇
  2000年   67967篇
  1999年   56655篇
  1998年   16776篇
  1997年   15073篇
  1996年   16054篇
  1995年   16270篇
  1994年   15133篇
  1993年   14174篇
  1992年   47133篇
  1991年   45780篇
  1990年   44003篇
  1989年   41855篇
  1988年   38786篇
  1987年   38093篇
  1986年   35877篇
  1985年   34648篇
  1984年   26367篇
  1983年   22122篇
  1982年   13850篇
  1981年   12452篇
  1980年   11729篇
  1979年   23558篇
  1978年   17082篇
  1977年   14392篇
  1976年   13185篇
  1975年   13730篇
  1974年   16103篇
  1973年   15404篇
  1972年   14179篇
  1971年   13042篇
  1970年   11890篇
  1969年   11108篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.

Background  

The justification for Nazi programs involving involuntary euthanasia, forced sterilisation, eugenics and human experimentation were strongly influenced by views about human dignity. The historical development of these views should be examined today because discussions of human worth and value are integral to medical ethics and bioethics. We should learn lessons from how human dignity came to be so distorted to avoid repetition of similar distortions.  相似文献   
952.
In their recent review article, Tanvetyanon and Stiff [1] pointedout that hypocalcemia is a frequent side-effect of intravenousbisphosphonates. This adverse event is usually mild and exceptionallysymptomatic, with the principle risk factors being pre-existinghypovitaminosis D, previous parathyroid surgery and intestinalresections. A direct consequence of hypocalcemia  相似文献   
953.
954.
Auditory P300 and eye tracking dysfunction in schizophrenic pedigrees   总被引:4,自引:0,他引:4  
Several psychophysiological abnormalities associated with schizophrenia have been proposed as genetic trait markers of vulnerability to the disorder. Smooth pursuit eye tracking dysfunction and abnormal long latency event-related potentials are the most promising candidates. Both are independent of the effects of psychotropic medication or mental state at the time of testing, and twin studies demonstrate that each has a high level of heritability. Having recorded smooth pursuit eye tracking and event-related potentials in 20 high-density schizophrenic families, we find abnormalities in one or both measures in most of the families studied. The abnormalities, when present, occur in the family members with schizophrenia and other forms of functional psychosis, and they have a bimodal distribution with approximately half the nonschizophrenic relatives also showing eye tracking dysfunction and/or abnormal event-related potentials. Some of these relatives had psychiatric symptoms; others were normal. Our results suggest that psychophysiological examination can help to clarify the boundaries of schizophrenia spectrum disorder. By helping to decide the phenotypic status of nonschizophrenic family members, this should increase the power of DNA linkage studies.  相似文献   
955.
We previously showed that a low frequency (1 Hz) train of perforant path stimulation evokes burst discharges in the dentate gyrus of hippocampal slices obtained from patients surgically treated for intractable temporal lobe epilepsy. We report here that multiple population spikes that characterize the burst discharge are blocked reversibly by the specific NMDA receptor antagonist, D-(-)-2-amino-5-phosphonovaleric acid (D-APV). The epileptiform discharge evoked in human dentate gyrus by stimulation trains of 1 Hz could be reproduced in the rat dentate gyrus in vitro by the same stimulation protocol but required the presence of low concentrations (0.2-0.6 mM) of extracellular magnesium. We suggest that low frequency orthodromic stimulation of dentate granule cells through the perforant path progressively evokes an increase in the activation of NMDA receptors resulting in burst discharges in tissue from epileptic patients.  相似文献   
956.
Infantile myofibromatosis is an uncommon, benign, probably hamartomatous proliferation of myofibroblasts. Its growth is typically self-limiting but histologically it can simulate a sarcoma. A rare case of solitary infantile myofibromatosis presenting as an intraoral mass in a 10-year-old girl is reported.  相似文献   
957.
Deep venous thrombosis in the surgical intensive care unit   总被引:4,自引:0,他引:4  
The ICU patient population is at a high risk for the development of deep venous thrombosis leading to a potentially fatal pulmonary embolism. It is vital to appreciate this risk and apply appropriate prophylaxis. Constant vigilance is required, as deep venous thrombosis and pulmonary emboli can develop and progress despite standard prophylactic measures. In unstable patients, more aggressive prophylaxis may be warranted, including the use of inferior vena cava filters. A high index of suspicion and a low threshold for screening and diagnostic testing will allow earlier recognition and treatment of this lifethreatening condition. Treatment decisions are based on clinical suspicion, diagnostic examination results, and the potential complications of difficult treatment modalities.  相似文献   
958.
A topographic CEEG investigation was carried out in 20 drug-free, DSM-IIIR diagnosed schizophrenics and in a group of matched healthy controls. The effects of acute and chronic haloperidol treatment were then assessed in the patient group. On the baseline recording, schizophrenics showed a widespread increase in delta, theta 1 and beta 3 amplitude. Acute haloperidol administration produced a decrease in delta and an increase in slow beta amplitude. After 28 days of treatment, delta and fast beta were reduced while theta 2 and alpha 1 were increased. CEEG abnormalities in schizophrenic subjects appear, therefore, to be reduced by chronic neuroleptic treatment.  相似文献   
959.
This study examined the relationship between risk factors and initiation of alcohol use over a 15-month period among a cohort of 7th graders who were abstainers at the time of initial testing. The relationship between risk factors and alcohol use was examined using a discriminant function analysis. At the univariate level, rejection of parental authority, deviant behavior, and sensation seeking were statistically significant. The discriminant function retained only three of the risk factors: rejection of parental authority, deviant behavior, and religious commitment. Implications for school-based prevention programs are discussed, particularly the need to target primary prevention programs based upon adolescents' risk.  相似文献   
960.
In an effort to evaluate whether differences exist in the hypothalamic-pituitary-thyroid axis of depressed children, a thyrotropin releasing hormone (TRH) stimulation test was administered to 55 prepubertal subjects who were divided into three groups matched for age and sex: a depressed group (endogenous N = 15, nonendogenous N = 15), a psychiatric nondepressed control group (N = 16), and a normal control group (N = 9). Each subject was tested at two dosages of TRH, 2 micrograms/kg and 7 micrograms/kg. Increasing age and female sex were positively correlated with a greater thyroid stimulating hormone (TSH) response. TSH response to TRH was examined with subjects reclassified by severe suicidal ideation, severe aggression, and parental history of alcoholism. Results of this study are contrasted with the adult psychiatric literature.  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