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   880篇
  免费   31篇
  国内免费   3篇
儿科学   28篇
妇产科学   11篇
基础医学   162篇
口腔科学   26篇
临床医学   169篇
内科学   114篇
皮肤病学   40篇
神经病学   111篇
特种医学   8篇
外科学   57篇
综合类   4篇
预防医学   83篇
眼科学   10篇
药学   48篇
肿瘤学   43篇
  2022年   9篇
  2021年   16篇
  2020年   12篇
  2019年   6篇
  2018年   9篇
  2017年   11篇
  2016年   17篇
  2015年   22篇
  2014年   24篇
  2013年   41篇
  2012年   56篇
  2011年   79篇
  2010年   40篇
  2009年   31篇
  2008年   43篇
  2007年   41篇
  2006年   49篇
  2005年   32篇
  2004年   47篇
  2003年   47篇
  2002年   35篇
  2001年   9篇
  2000年   4篇
  1999年   7篇
  1998年   9篇
  1997年   19篇
  1996年   7篇
  1995年   14篇
  1994年   4篇
  1993年   4篇
  1992年   9篇
  1991年   10篇
  1990年   4篇
  1989年   5篇
  1987年   4篇
  1982年   4篇
  1979年   4篇
  1977年   5篇
  1976年   4篇
  1968年   4篇
  1939年   6篇
  1937年   3篇
  1934年   5篇
  1932年   3篇
  1930年   5篇
  1928年   8篇
  1927年   3篇
  1924年   4篇
  1923年   3篇
  1922年   5篇
排序方式: 共有914条查询结果,搜索用时 15 毫秒
1.
One hundred seventy-five consecutive recruits entering the Fort Jackson Fitness Company were evaluated for Upper Body Strength, Flexibility, and Cardiovascular Fitness, and the results were compared with those of 60 soldiers entering Basic Training directly from the Reception Station. Injury rate and end-cycle performance were compared between Fitness Company graduates and their regular basic trainee cohort. The study showed that the Push-up repetition and two-mile run times were still below the standard for the Post. Sick call rate was also significantly higher among the less conditioned troops. Sit-up repetition and other basic soldiering skills, however, as well as EPTS (discharges for medical conditions existing prior to service) and ELS (entry level separation) rates, were equal. Increase of Fitness Company graduation requirements and dissemination of standards and requirements to potential recruits in high schools, colleges, and other public institutions are recommended.  相似文献   
2.
3.
The reactivity of a panel of antiganglioside monoclonal antibodies with a number of melanoma cell lines having different ganglioside composition profiles was studied. One cell line synthesized only GM3, one produced both GM3 and GD2, 2 had GM3 and GD3 as their major gangliosides, and 2 others synthesized approximately equal amounts of GM3, GM2, GD3, and GD2 gangliosides. Antibody reactivity with viable cells was analyzed by: (a) flow cytometry on suspension cells; and (b) mixed hemagglutination assays or immune adherence assays on monolayer cells in culture. GM3 was efficiently detected only in the cell line having GM3 as its sole ganglioside. In the other cell lines, GM3 was difficult to detect even in cells in which it made up a high proportion (up to 50%) of the total ganglioside content. GM2 was easily detectable only in JB-RH melanoma cells (which contain only GM3 and GM2). GD3 was the most reactive ganglioside in 2 cell lines and GD2 in 2 other lines. In general, the most complex ganglioside present in a cell was the one most accessible to antibody. The differential exposure at the cell surface of specific gangliosides may have implications for antibody-directed tumor detection and therapy and for cell-protein or cell-cell interactions that involve glycolipids.  相似文献   
4.
5.
6.
BACKGROUND: We describe the production in Escherichia coli as a recombinant protein of clinical grade wild-type Bet v 1a (rBet v 1a), to be used as a candidate vaccine against birch pollen allergy. METHODS: This recombinant protein was purified by hydrophobic interaction and ion exchange chromatography and characterized by SDS-PAGE, immunoprint and circular dichroism in parallel with natural Bet v 1 (nBet v 1) purified from a birch pollen extract. We also compared rBet v 1 and nBet v 1 for their capacity to induce histamine release from basophils and to stimulate T lymphocyte proliferation. RESULTS: rBet v 1a appears in SDS-PAGE as an 18-kDa monomeric protein, whereas purified nBet v 1 comprises a mixture of isoforms (resolving as three distinct bands and six spots after 1-dimensional and 2-dimensional electrophoresis, respectively). Both recombinant and natural purified Bet v 1 molecules are recognized by IgE from birch pollen-allergic patients as well as anti-Bet v 1 murine monoclonal antibodies, suggesting that the recombinant protein is correctly folded in a native configuration. Circular dichroism analysis confirmed that the two Bet v 1 molecules exhibit similar 3-dimensional structures, even if rBet v 1a appears more compact and stable in thermodenaturation/renaturation experiments. Both rBet v 1 and nBet v 1 induce the degranulation of sensitized basophils and proliferation of Bet v 1-specific T lymphocytes in a similar manner. CONCLUSIONS: On the basis of these structural and biological properties, rBet v 1a is a valid candidate vaccine against birch pollen allergy, currently evaluated in humans.  相似文献   
7.
HLA Antigens in 16 Families with Xeroderma Pigmentosum   总被引:1,自引:0,他引:1  
Xeroderma pigmentosum is an autosomal recessive disease. HLA-A and -B typing was performed on peripheral blood lymphocytes and platelets. Sixteen Tunisian families were typed with 37 patients and 108 relatives. Genetic transmission of the disease and of the HLA system seemed to be independent in this study. Comparison of HLA gene frequencies between (unrelated) parents of patients and a control population showed no difference, proving that there is no clear association in populations between deleterious XP genes and a particular HLA gene. However, an excess of identical HLA among pairs of diseased siblings would suggest that the disease is polymorphic and a form of the XP could be linked to HLA.  相似文献   
8.
Summary Twenty spinal shock patients were investigated with simultaneous urethrovesical, anal and rectal pressure recordings and EMG of the external urethral and anal sphincters. Dynamic and static urethral pressure profiles (UPP) were carried out with empty and full bladder. Baldder filling was accompanied by an increased resistance in the internal sphincter zone, which in turn was paralleled in the majority of cases by an elevation of pressure in the membranous urethra without concomitant increase of its EMG activity. This is suggestive of an increased sympathetic activity in the bladder neck area and in the smooth muscle component of the external urethral sphincter. Dynamic pullthrough UPP's displayed higher resistances in the membranous urethra than static interrupted UPP's pointing to the role played by the urethral muscosal receptors in eliciting artefactual results. Higher pressures were recorded in the juxtabulbar portion of the membranous urethra than in its mid portion pointing to a gradient of pressure within the external urethral sphincter itself. The amount of EMG activity recorded in the anal and urethral sphincters at rest was somewhat decreased; high pressures and distinct reflex activity were recorded in both sphincters showing that they escape spinal shock characterized primarily by areflexia. After defining spinal shock a rational explanation based upon neuroanatomical and neurophysiological findings is offered as to why somatic activity of the sacral segments escapes it as evidenced by clincial, urodynamic, and electromyographic recordings.  相似文献   
9.
Adverse sexual health outcomes remain disproportionately high for Latino adolescents. To examine sexual risk behaviors in Latino adolescents, we conducted in-depth interviews with 18 Latino parents and 13 school staff members and carried out 1 year of fieldwork in the school and community. “It's a touchy subject [sex] here” exemplified the reluctance of addressing sexual risk behaviors. Community- and systems-level strategies are recommended.  相似文献   
10.
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