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   3770篇
  免费   450篇
  国内免费   3篇
耳鼻咽喉   28篇
儿科学   101篇
妇产科学   115篇
基础医学   397篇
口腔科学   83篇
临床医学   583篇
内科学   946篇
皮肤病学   67篇
神经病学   278篇
特种医学   135篇
外科学   427篇
综合类   86篇
一般理论   2篇
预防医学   438篇
眼科学   27篇
药学   166篇
中国医学   1篇
肿瘤学   343篇
  2023年   39篇
  2022年   22篇
  2021年   73篇
  2020年   45篇
  2019年   66篇
  2018年   101篇
  2017年   89篇
  2016年   97篇
  2015年   71篇
  2014年   116篇
  2013年   160篇
  2012年   187篇
  2011年   177篇
  2010年   122篇
  2009年   138篇
  2008年   169篇
  2007年   181篇
  2006年   202篇
  2005年   167篇
  2004年   182篇
  2003年   122篇
  2002年   134篇
  2001年   134篇
  2000年   138篇
  1999年   97篇
  1998年   46篇
  1997年   52篇
  1996年   50篇
  1995年   34篇
  1994年   32篇
  1993年   32篇
  1992年   78篇
  1991年   67篇
  1990年   77篇
  1989年   60篇
  1988年   71篇
  1987年   57篇
  1986年   53篇
  1985年   48篇
  1984年   34篇
  1983年   36篇
  1982年   22篇
  1981年   19篇
  1980年   19篇
  1979年   38篇
  1978年   24篇
  1977年   23篇
  1976年   20篇
  1975年   21篇
  1973年   19篇
排序方式: 共有4223条查询结果,搜索用时 0 毫秒
11.
12.
Three disorders of facial recognition and perception in acute schizophrenia and mescaline-induced psychosis are described and illustrated using original clinical and experimental material: "affective prosopagnosia" or stress-related dysfunctional face recognition; "physiognomization" of the environment or persistent illusions and hallucinations of nonspecific faces; and the "mirror phenomenon" or the experience of inner alienation from one's reflected face, which is perceived as independently alive, sinister, and generally physically distorted. It is proposed that neuropsychology suggests relationships between these phenomena that might otherwise be less apparent. No final neurobiological solution to the problem of dysfunctional facial perception and recognition in psychosis is presented, but various insights and suggestive models from the neurosciences are discussed. Attention is also paid to the conditions under which one might need to combine neuropsychological approaches with hermeneutically oriented analyses.  相似文献   
13.
A Harrington 《Der Nervenarzt》1989,60(10):603-611
The problem of the localisation of mental functions in the brain is historically analysed with special attention to its implications for psychiatry. The aim is not to discuss the historical details of the relationship between psychiatric models of madness and neurological models of brain functioning, but to cast some light on the broad intellectual and social framework within which the relationship became possible in the first place. It is argued that debates about the localizability of psychological processes are always more than just debates about structure-function correlation, and must in fact be ultimately understood as part of the much larger historical attempt within the natural sciences to "naturalize" man and his mind. Emphasis is laid on the extent to which different positions within the localisation debate have been influenced by unspoken social (political, religious) and philosophical factors, and questions are raised about the implications of this fact for modern neuropsychology and neuropsychiatry.  相似文献   
14.
15.
Plasma HIV RNA is a useful surrogate marker for predicting HIV-1 disease progression in infected individuals but provides no information regarding the infectious viral titer. Traditional assays of infectious HIV-1 are, however, time consuming, insensitive, use non-standardized reagents and are subject to selection bias introduced by prolonged cultivation. In this pilot study infectious HIV-1 was detected directly in patient plasma using the indicator line HeLa-CD4-CCR5-LTR/beta-gal in a centrifugation-culture method. Replication competent HIV-1 was identified within 2 days of tissue culture inoculation in six (26%) of 23 plasma specimens. The capability of a new cell line, MT4-CCR5-tat, to amplify plasma HIV-1 was also tested. HIV was cultivated from ten (71%) of 14 specimens using MT4-CCR5-tat cells before titering the virus with the indicator cell assay. Using these stable cell lines in refined versions of this assay it may be feasible to develop rapid, simple methods for titering infectious plasma HIV-1 and for testing the susceptibility of the virus to antiretroviral drugs.  相似文献   
16.
Summary A polymerase chain reaction (PCR) was designed which is specific toMacaca fascicularis (cynomolgus monkey) isolates of B virus. The PCR primers produced the expected 188 basepair product from the Cyno 2 strain and seven other cynomolgus monkey isolates of B virus. Oligomer hybridization with a 31-mer oligonucleotide was used to confirm the origin of this product. The PCR failed to amplify DNA of Epstein-Barr virus, cytomegalovirus, varicella-zoster virus, and other alphaherpesviruses (herpes simplex virus types 1 and 2, four SA 8 isolates and three rhesus isolates of B virus). PCR testing of swabs obtained from four orally-infected cynomolgus monkeys confirmed the presence of B virus DNA in samples previously shown to be positive by culture. In addition, PCR detected B virus in several swabs from infected monkeys that were culture negative. Total DNA extracts from the trigeminal and sacral ganglia of these animals were tested by nested PCR and B virus DNA was detected in the trigeminal ganglia of 3 of the 4 orally-infected cynomolgus monkeys. Nested PCR did not detect B virus DNA in total DNA extracts obtained from the brains of the four monkeys.  相似文献   
17.
Tau protein is a major component of paired helical filaments (PHFs) which constitute the characteristic neurofibrillary tangle lesions observed in Alzheimer's disease. Two tau mAbs have been produced which show distinct patterns of immunoreactivity with intact human tau and with tau incorporated in PHFs. The mAb 423 recognises PHFs but not human tau on immunoblots whereas mAb 7/51 reacts with human tau but its epitope is buried within the PHF and is only exposed after formic acid treatment. A competitive ELISA has been developed for both of these mAbs and these have been used to quantify the two distinct tau epitopes in PHFs. Samples containing antigen are incubated with horseradish peroxidase-conjugated mAb at 4 degrees C for 16 h and non-adsorbed antibody then measured by binding, at 37 degrees C for 1 h, to a fragment of tau coated on microtitre plates. Bound enzyme-labelled antibody is measured kinetically using a spectrophotometer capable of automatically mixing the samples throughout a 2-min incubation with substrate and chromogen. The interfacing of the plate reader with a computer permits competitive curves to be plotted automatically using Softmax. Curves are fitted using a 4-parameter logistic algorithm which allows one to determine the relative immunoreactivity for different samples. The application of these assays to monitoring biochemical fractions and quantifying distinct immunochemical presentations of tau protein with these two mAbs is described.  相似文献   
18.
Based upon differences in open field and conflict behaviors, the MR/Har and MNRA/Har rat strains have been proposed as a genetically-based "animal model" for the study of emotionality and/or anxiety. The present study compared the MR/Har and MNRA/Har rat strains in the Defensive Burying paradigm. Prior to testing, female MR/Har and MNRA/Har rats were placed in a 40 X 30 X 40 cm Plexiglas chamber containing clay bedding material (5 cm deep) for 30 minute periods on each of four consecutive days. On the fifth day, a wire wrapped prod was placed at one end of the chamber. Rats were placed in the chamber singly and a 3 mA shock was delivered upon contact with the prod. Defensive Burying behavior (i.e., the moving of bedding material toward or over the prod) was recorded for each animal for 15 minutes postshock. There was no MR/Har versus MNRA/Har difference in the percent of animals exhibiting Defensive Burying, nor was there a MR/Har versus MNRA/Har difference in the latency to initiation or the duration of this behavior. Thus, these genetically-defined Maudsley rat strains do not appear to differ in all "animal models" for the study of anxiety or fear.  相似文献   
19.
Family history is the major risk factor in the aetiology of breast cancer. Breast screening is currently available to women from the age of 50 to 64 through the National Breast Screening Programme. There is, however, an equivalent risk of developing breast cancer below 50 for first degree relatives of women diagnosed with breast cancer premenopausally. We have estimated the risk of breast cancer for relatives of women affected at different ages and used these to establish a family cancer clinic offering breast screening based on individual risk. In three years we have seen 851 patients. Compliance for annual radiology was in excess of 83% over this period and of five cancers detected one had a lump at presentation, two developed interval breast lumps, and two were asymptomatic.  相似文献   
20.
Fifty-four patients with chronic progressive multiple sclerosis received prednisone plus oral low-dose cyclophosphamide and either true plasmapheresis (PP) or "sham" PP weekly for 20 weeks in a double-blind controlled study. Immunosuppressive drug therapy alone (sham PP group, n = 29) was associated with improvement (greater than or equal to one step in Kurtzke Disability Status Scale [DSS]; mean change of 1.5) in 8 and stabilization of MS in 18 patients, with this status sustained in 23 patients at follow-up, 11 months after entry. In contrast, 14 of 26 patients who received "true" PP improved (greater than or equal to one step in DSS; mean change of 2.6), and 11 more were stable, with these changes sustained in 23 of 26 patients at follow-up. These differences, overall, between the PP and sham PP groups were significant at p less than 0.007.  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