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   1519篇
  免费   133篇
  国内免费   8篇
耳鼻咽喉   2篇
儿科学   54篇
妇产科学   20篇
基础医学   157篇
口腔科学   38篇
临床医学   198篇
内科学   306篇
皮肤病学   28篇
神经病学   115篇
特种医学   148篇
外科学   163篇
综合类   93篇
一般理论   2篇
预防医学   85篇
眼科学   94篇
药学   91篇
  1篇
中国医学   1篇
肿瘤学   64篇
  2020年   12篇
  2019年   15篇
  2018年   26篇
  2017年   17篇
  2016年   26篇
  2015年   30篇
  2014年   43篇
  2013年   66篇
  2012年   49篇
  2011年   54篇
  2010年   38篇
  2009年   58篇
  2008年   54篇
  2007年   39篇
  2006年   70篇
  2005年   26篇
  2004年   44篇
  2003年   48篇
  2002年   44篇
  2001年   22篇
  2000年   20篇
  1999年   20篇
  1998年   40篇
  1997年   56篇
  1996年   52篇
  1995年   37篇
  1994年   39篇
  1993年   45篇
  1992年   39篇
  1991年   25篇
  1990年   23篇
  1989年   28篇
  1988年   32篇
  1987年   30篇
  1986年   25篇
  1985年   20篇
  1984年   30篇
  1983年   15篇
  1982年   27篇
  1981年   18篇
  1980年   16篇
  1979年   29篇
  1978年   21篇
  1977年   16篇
  1976年   21篇
  1975年   19篇
  1974年   12篇
  1973年   13篇
  1971年   14篇
  1967年   15篇
排序方式: 共有1660条查询结果,搜索用时 15 毫秒
31.
32.
A self-refrigerated suit using dry ice as cooling agent and allowing the wearer to move about freely is described. Its efficiency during exposure to heat (dry bulb temperature, ta = 46 C; wet bulb temperature, twb = 35 C) and heavy physical work on a treadmill has been demonstrated by experiments on 26 subjects. The heart rate is reduced and the body temperature is decreased. The way in which this self-refrigerated suit reduces the heat load is discussed and the usefulness of its application is emphasized.  相似文献   
33.
34.
35.
36.
Cytogenetic and histologic correlations in malignant lymphoma   总被引:9,自引:0,他引:9  
Although a number of studies have indicated correlations between histologic subtypes of tumors and certain nonrandom chromosome changes, cytogenetic studies of lymphoma are in an early stage compared to those of leukemia. No comprehensive analysis of available data has so far been attempted in the literature either. Here we present an analysis of chromosome changes and their correlation with subtypes of lymphoma studied by conventional histology and cell surface markers, as observed in two sets of data: a group of 65 karyotypically abnormal tumors sequentially ascertained and studied by us during the period January 1, 1984 to April 30, 1985, and a larger data set derived by combining our data with those from two published series from the University of Minnesota that are comparable to our data. These combined data, which comprise the largest data set on the cytogenetics of lymphomas assembled so far, enabled a comprehensive analysis of correlation between chromosome change and tumor histology and the patterns of chromosome instability in these tumors. We found several significant associations, some previously described and others now recognized, between nonrandom chromosome gains, breaks, translocations, and deletions and histologic subtypes of tumors that characterize lymphomas. The data indicate that finding of chromosome breaks at certain sites (eg, 8q24, 14q32, 18q21) is of diagnostic value in dealing with cases of unusual lymphoma. Furthermore, nonrandom chromosome breakage exhibited three distinct patterns that reflected three levels of etiologically relevant genetic change.  相似文献   
37.
Immunoglobulin V regions and the B cell   总被引:7,自引:2,他引:7  
Stewart  AK; Schwartz  RS 《Blood》1994,83(7):1717-1730
  相似文献   
38.
Quito  FL; Beh  J; Bashayan  O; Basilico  C; Basch  RS 《Blood》1996,87(4):1282-1291
Fibroblast growth factor-4 (FGF-4), a highly mitogenic protein encoded by the k-fgf/hst oncogene, stimulates the growth of a variety of cells of mesenchymal and neuroectodermal origin. Addition of FGF-4 to human long-term bone marrow cultures increased both the cell density of the stromal layer and the number of hematopoietic colony forming cells in the cultures in a dose-dependent manner. Hematopoiesis in the stromal layer persisted for up to 8 months. Erythropoiesis was maintained for up to 4 weeks, but granulocytes were the predominant nonadherent cell type. Cultures treated with FGF had increased numbers of monocytes compared with control cultures and some CD14+, CD45+ monocytes could still be detected after 8 months of continuous culture. The addition of the growth factor increased the rate of growth of the stromal layer and appeared to delay its senescence. Subcultures made in the presence of FGF-4 had up to 10-fold increases in plating efficiency and grew as relatively uniform monolayers. These subcultures retained the capacity to support hematopoiesis for several months, while untreated subcultures, made without FGF-4, grew erratically and generally lost the capacity to support hematopoiesis within 4 to 6 weeks. The improved growth after subculture greatly enhanced the reliability of limit- dilution assays of multipotential hematopoietic stem cells that use stromal cell monolayers. The primary effect of FGF-4 appeared to be on the stromal cells of the long-term bone marrow cultures, but a direct effect on hematopoietic progenitors could not be ruled out.  相似文献   
39.
40.
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