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   1383篇
  免费   41篇
  国内免费   78篇
耳鼻咽喉   2篇
儿科学   48篇
妇产科学   33篇
基础医学   132篇
口腔科学   25篇
临床医学   150篇
内科学   349篇
皮肤病学   57篇
神经病学   75篇
特种医学   275篇
外科学   77篇
综合类   28篇
一般理论   3篇
预防医学   70篇
眼科学   23篇
药学   67篇
中国医学   3篇
肿瘤学   85篇
  2023年   7篇
  2022年   9篇
  2021年   7篇
  2020年   13篇
  2019年   19篇
  2018年   19篇
  2017年   13篇
  2016年   21篇
  2015年   27篇
  2014年   27篇
  2013年   37篇
  2012年   46篇
  2011年   42篇
  2010年   39篇
  2009年   58篇
  2008年   45篇
  2007年   72篇
  2006年   34篇
  2005年   35篇
  2004年   28篇
  2003年   22篇
  2002年   21篇
  2001年   31篇
  2000年   32篇
  1999年   19篇
  1998年   88篇
  1997年   75篇
  1996年   60篇
  1995年   53篇
  1994年   49篇
  1993年   46篇
  1992年   32篇
  1991年   33篇
  1990年   34篇
  1989年   41篇
  1988年   40篇
  1987年   28篇
  1986年   24篇
  1985年   25篇
  1984年   20篇
  1983年   13篇
  1982年   19篇
  1981年   9篇
  1980年   14篇
  1979年   8篇
  1978年   9篇
  1977年   17篇
  1976年   14篇
  1975年   13篇
  1969年   3篇
排序方式: 共有1502条查询结果,搜索用时 62 毫秒
71.
The protein SV-IV, one of the major secretory proteins produced by the rat seminal vesicle epithelium, has been found to possess a marked ability to inhibit in vitro the phagocytic properties of activated peritoneal rat macrophages, by a mechanism that apparently involves phagocytes and target cells. Although SV-IV is a substrate for transglutaminase (TGase), an enzyme secreted by activated macrophages, TGase does not seem to play any significant role either in the binding of the protein to the cells participating in the phagocytic process or in the inhibition of macrophage phagocytosis by SV-IV. The significance of the findings in relation to the reproductive process and their possible clinical implications are discussed.  相似文献   
72.
Role of the amplitude of the gonadotropin surge in the rat   总被引:3,自引:0,他引:3  
Ovaries that contained pregnant mare's serum gonadotropin-induced preovulatory follicles were perifused for 21 hours with (1) control media, (2) 5%, (3) 30%, or (4) 85% of the gonadotropin surge. All of the gonadotropin surges induced oocyte maturation and enhanced progesterone (P) secretion. Ovulated oocytes were observed in one of four ovaries in the 85% surge group. These data demonstrate that only a small percentage of the gonadotropin surge is required to induce a maximal P secretion and oocyte maturation. Because neither P secretion nor oocyte maturation is enhanced with increasing gonadotropin levels, these two follicular responses must be mediated through a threshold-dependent mechanism such that once the threshold level is obtained, a maximum response is induced. Greater than 85% of the surge appears to be required to induce follicular rupture, suggesting that the threshold for the follicular rupture is greater than that for either P secretion or oocyte maturation.  相似文献   
73.
74.
Recent reports have demonstrated that EBV can be used as a target of specific CTL-based treatments in severe chronic EBV, immunoblastic B cell lymphoma and Hodgkin's disease (HD). Based upon the promising results form these in vivo studies, it has been suggested that an antigen-specific CTL-based immunotherapy may be of benefit in treating EBV-associated tumors such as HD and nasopharyngeal carcinoma (NPC) which express the potentially immunogenic antigens, LMP1 and LMP2a. Recent work form our group has demonstrated that LMP2a-specific CTLs may be generated in vitro using autologous antigen presenting cells which have been transfected with polyadenylated LMP2a RNA in the presence of a cationic lipid. In this study, we demonstrate that the presence of the lipid enhances dendritic cell (DC) transfection efficiency and appears to protect the intracellular LMP2a RNA from degradation by cellular RNAses. Significantly, these improvements resulted in the transfected DCs having a superior ability to stimulate autologous T cell proliferation. These LMP2a + DCs were used to stimulate LMP2a-specific effector cells which were predominantly a mixture of cytotoxic and helper CD4+ T cells. The molecular mechanisms whereby these CD4+ T cells lyzed their LMP2a-expressing targets was investigated and we show that, although expressing Fas ligand on their surface, LMP2a-specific CD4+ effector cells kill their targets using the Ca2+-dependent perforin/granzyme pathway which is the same mechanism used by CD8+ CTLs.  相似文献   
75.
76.
77.
78.
79.
Numerous structures are included in the irradiated volume of patients presenting with head and neck cancer: skin, mucosa, bone, teeth, cartilage, muscles, salivary glands, etc. Curative intent treatment of such tumours requires aggressive approach which can lead to severe sequellae. These sequellae are in most cases dose-dependent and volume-dependent. However, an appropriate technique might decrease the severity of such sequellae. Details of these late changes are presented, including their pathophysiology, clinical syndromes, potential treatment, and prevention.  相似文献   
80.
Ambulatory blood pressure monitoring (ABPM) in adults is proving to be useful. The aim of this study was to determine if ABPM is accurate in the lower blood pressure range encountered in children and, equally important, whether it is acceptable to children. Thirty one children, between the ages of 6 and 18 years, were assessed using an ambulatory blood pressure monitor that uses an auscultatory method. Blood pressure was measured in the contralateral arm with a mercury sphygmomanometer and an oscillometric device at the beginning and end of the study for comparison. Over a blood pressure range of 90-130 mm Hg systolic and 40-80 mm Hg diastolic, a close agreement was found with the sphygmomanometer; the limits of agreement (+/- 2 SD) were 11.6 mm Hg for systolic blood pressure and 13.6 mm Hg for diastolic blood pressure. The bias was less than 1.0 mm Hg. The ambulatory device was worn by all patients for at least 16 hours with an average of 52 recordings per patient. The majority found the device comfortable to wear and were not woken from sleep.  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