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   18098篇
  免费   1792篇
  国内免费   21篇
耳鼻咽喉   153篇
儿科学   630篇
妇产科学   547篇
基础医学   2654篇
口腔科学   297篇
临床医学   2118篇
内科学   3491篇
皮肤病学   229篇
神经病学   1535篇
特种医学   567篇
外国民族医学   4篇
外科学   2192篇
综合类   446篇
一般理论   12篇
预防医学   2094篇
眼科学   383篇
药学   1386篇
中国医学   13篇
肿瘤学   1160篇
  2021年   237篇
  2020年   154篇
  2019年   263篇
  2018年   281篇
  2017年   234篇
  2016年   245篇
  2015年   256篇
  2014年   368篇
  2013年   568篇
  2012年   767篇
  2011年   846篇
  2010年   494篇
  2009年   415篇
  2008年   717篇
  2007年   778篇
  2006年   687篇
  2005年   730篇
  2004年   728篇
  2003年   722篇
  2002年   648篇
  2001年   595篇
  2000年   607篇
  1999年   502篇
  1998年   216篇
  1997年   178篇
  1996年   168篇
  1995年   182篇
  1994年   149篇
  1993年   152篇
  1992年   443篇
  1991年   443篇
  1990年   447篇
  1989年   396篇
  1988年   414篇
  1987年   405篇
  1986年   355篇
  1985年   323篇
  1984年   293篇
  1983年   243篇
  1982年   138篇
  1979年   247篇
  1978年   191篇
  1977年   161篇
  1976年   174篇
  1975年   166篇
  1974年   173篇
  1973年   204篇
  1972年   160篇
  1971年   146篇
  1970年   142篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
IL2-PE40 is a chimeric protein composed of human interleukin-2 (IL2) genetically fused to a modified form of Pseudomonas exotoxin lacking the cell recognition domain. IL2-PE40 is cytotoxic for IL2 receptor-bearing lymphocytes in culture and can inhibit activation of T cells in vivo. IL2-PE40 can significantly diminish antigen-stimulated proliferation of lymphocytes sensitized to myelin basic protein. Intraperitoneal administration of IL2-PE40 not only markedly inhibits the clinical manifestations of adoptively transferred relapsing experimental allergic encephalomyelitis but also dramatically reduces both inflammation and demyelination characteristic of the disease.  相似文献   
5.
6.
Incestuous child sexual abuse has received increasing attention recently, but relatively little attention has focused on the multigenerational dimensions of this problem. The case presented places incest into a multigenerational context and demonstrates how quickly family relationships may become eroticized in an uncommon form: between sisters.  相似文献   
7.
While much time has been spent deliberating about the definition of play, little emphasis has been placed on what children themselves perceive as play. The aim of the present study was to examine social context as a cue for children's perceptions of play and learning. Ninety-two children aged between four and six years (mean four years nine months) participated in the study and completed the Activity Apperception Story Procedure. Children were asked to sort photographic stimuli into those they believed depicted play/not play and learning/not learning. Each of the stimuli were identified by independent raters as containing one of the following social cues; teacher absence (solitary activity, parallel activity or cooperative activity) or teacher presence (teacher involved activity or teacher directed activity). Findings revealed that children associated teacher absence with play. More specifically, children made links between play and the presence of peers (parallel and cooperative activity). Findings are discussed in relation to play in the early years curriculum, differences in children's early educational experiences and the importance of understanding children's perceptions of play.  相似文献   
8.
To evaluate the use of pelvic ultrasonography in the diagnosis and management of female adolescents with pelvic inflammatory disease (PID), sonograms of 60 patients with PID were compared with those of 40 age-matched controls. Sonograms were evaluated for adnexal volume, adnexal adherence, uterine size, and the presence of cul-de-sac fluid. Eleven (19.3%) of the 57 patients with PID, in whom adequate sonograms were obtained, had tubo-ovarian abscesses; in seven of these patients, the abscesses were diagnosed ultrasonographically before suspected clinically. Even in those patients without tubo-ovarian abscesses, the mean (+/- SD) adnexal volume in the PID group was significantly larger than that of the control group (11.0 +/- 6.8 cm3 vs 5.2 +/- 2.7 cm,3 respectively). Adnexal adherence, uterine size, and the presence of cul-de-sac fluid were not useful in differentiating patients with PID from normal controls. Pelvic ultrasonography can be a useful adjunct in the diagnosis and management of PID in adolescents and may, in some instances, provide diagnoses in the absence of clinical findings.  相似文献   
9.
Data obtained on a sample of persons with mild to profound degrees of mental retardation (N = 8255) and ranging from birth to 98 years of age were factor analyzed to provide information on the structure of maladaptive behavior relative to age and degree of mental retardation. Using the Problem Behavior scales of the Inventory for Client and Agency Planning, two principal factors emerged for children with mild to profound degrees of retardation: Internalized Maladaptive and Externalized Maladaptive. For adolescents and young adults, a three-factor solution which varied by degree of retardation was most appropriate. For middle and older adults, three- and four-factor solutions were identified across all ages and degrees of retardation. Across all samples as many as six different types of dimensions were identified, indicating that the structure of maladaptive behavior may well be influenced by age and level of mental retardation.  相似文献   
10.

Background  

The objective of this study was to examine missed opportunities for participation in a prevention of mother-to-child transmission (PMTCT) programme in three sites in South Africa. A rapid anthropological assessment was used to collect in-depth data from 58 HIV-positive women who were enrolled in a larger cohort study to assess mother-to-child HIV transmission. Semi-structured interviews were conducted with the women in order to gain an understanding of their experiences of antenatal care and to identify missed opportunities for participation in PMTCT.  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