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   1058篇
  免费   44篇
  国内免费   37篇
儿科学   37篇
妇产科学   29篇
基础医学   58篇
口腔科学   35篇
临床医学   478篇
内科学   118篇
皮肤病学   7篇
神经病学   48篇
特种医学   114篇
外科学   41篇
综合类   26篇
预防医学   44篇
眼科学   7篇
药学   44篇
肿瘤学   53篇
  2023年   5篇
  2021年   4篇
  2020年   5篇
  2019年   5篇
  2018年   13篇
  2017年   5篇
  2016年   8篇
  2015年   18篇
  2014年   19篇
  2013年   37篇
  2012年   16篇
  2011年   6篇
  2010年   27篇
  2009年   35篇
  2008年   25篇
  2007年   32篇
  2006年   25篇
  2005年   21篇
  2004年   25篇
  2003年   21篇
  2002年   26篇
  2001年   37篇
  2000年   25篇
  1999年   37篇
  1998年   92篇
  1997年   86篇
  1996年   80篇
  1995年   66篇
  1994年   50篇
  1993年   56篇
  1992年   19篇
  1991年   26篇
  1990年   27篇
  1989年   22篇
  1988年   34篇
  1987年   11篇
  1986年   14篇
  1985年   12篇
  1984年   13篇
  1983年   7篇
  1982年   9篇
  1981年   6篇
  1980年   7篇
  1979年   6篇
  1978年   4篇
  1977年   3篇
  1976年   3篇
  1971年   2篇
  1962年   1篇
  1958年   2篇
排序方式: 共有1139条查询结果,搜索用时 15 毫秒
21.
Chang  CS; Sassa  S 《Blood》1985,65(4):939-944
Physicochemical and immunologic properties of delta-aminolevulinate (ALA) dehydratase in human K562 erythroleukemia cells were examined. ALA dehydratase activity was found to increase in K562 cells after treatment with butyric acid or selenium oxide. Enzyme activity in untreated K562 cells was comparable to that in normal adult erythrocytes but was increased three- to six-fold in K562 cells treated with 1.2 mmol/L butyric acid or 0.03 mmol/L selenium oxide. The Michaelis-Menten constant (Km), the inhibitor constant (Ki), and elution profile by diethylaminoethyl (DEAE) cellulose chromatography were similar for ALA dehydratase from K562 cells and normal human adult and human fetal erythrocytes. However, ALA dehydratase from K562 cells did not react with a monospecific rabbit antibody against ALA dehydratase purified from normal adult erythrocytes, although the antibody reacted with the enzyme from normal adult and fetal red cells. These findings indicate that ALA dehydratase in K562 cells is immunologically distinct from the normal enzyme.  相似文献   
22.
23.
Storage of skin grafts for later use is one of the standard applications in surgery. It is the most preferred method to maintain at +4°C in refrigeration after wrapping the surplus grafts into sterile gauze pad moistened with saline. Although there are many studies on the storage of skin grafts, less is known about storing skin grafts with PRP. Twenty‐five pieces of 1 × 1 cm2 partial thickness skin graft were harvested from 12 patients during the reduction mammoplasty operation. Twenty‐four grafts were divided into 4 groups, and each group consisted of 6 grafts, 1 graft was analyzed as Day 0. Grafts in Group 1, 2, and 3 were wrapped by sterile gauze pad moistened by either saline (Group 1) or Hartman (Group 2) or PRP (Group 3). Grafts were analyzed macroscopically and microscopically. There were no significant differences between media for the first 10 days. Decrease in viability was less in saline and PRP wrapped grafts at 20 day, viability decreased significantly in all environments after 20 days. Although there was no significant difference in saline or PRP storage, it was observed macroscopically that the grafts stored in the PRP appeared better.  相似文献   
24.
25.
26.
Cultural Consensus Analysis as a Tool for Clinic Improvements   总被引:2,自引:0,他引:2       下载免费PDF全文
Some problems in clinic function recur because of unexpected value differences between patients, faculty, and residents. Cultural consensus analysis (CCA) is a method used by anthropologists to identify groups with shared values. After conducting an ethnographic study and using focus groups, we developed and validated a CCA tool for use in clinics. Using this instrument, we identified distinct groups with 6 important value differences between those groups. An analysis of these value differences suggested specific and pragmatic interventions to improve clinic functioning. The instrument has also performed well in preliminary tests at another clinic.  相似文献   
27.
Susceptibility to autoimmune insulin-dependent (type 1) diabetes mellitus is determined by a combination of environmental and genetic factors, which include variation in MHC genes on chromosome 6p21 (IDDM1) and the insulin gene on chromosome 11p15 (IDDM2). However, linkage to IDDM1 and IDDM2 cannot explain the clustering of type 1 diabetes in families, and a role for other genes is inferred. In the present report we describe linkage and association of type 1 diabetes to the CTLA-4 gene (cytotoxic T lymphocyte associated-4) on chromosome 2q33 (designated IDDM12). CTLA-4 is a strong candidate gene for T cell- mediated autoimmune disease because it encodes a T cell receptor that mediates T cell apoptosis and is a vital negative regulator of T cell activation. In addition, we provide supporting evidence that CTLA-4 is associated with susceptibility to Graves' disease, another organ- specific autoimmune disease.   相似文献   
28.
29.
30.
Our goals were to determine the prognostic value of a yolk sac or fetal heart motion seen during an early accurately dated transvaginal ultrasound (TVU). We reviewed 225 consecutive pregnancies for fetal heart motion data. Furthermore, 63 pregnancies following in-vitro fertilization were reviewed for yolk sac information. The TVU was performed between 5 and 6 weeks following presumed conception (heart motion data) and between 22 and 32 days following in-vitro fertilization (yolk sac data). Pregnancies were followed until an ongoing pregnancy or spontaneous abortion was documented. The presence of a yolk sac between 22 and 32 days from fertilization was associated with the development of fetal heart motion in 94% of cases. The absence of the yolk sac by 32 days after fertilization was always associated with a poor outcome. In women < 36 years of age, the presence of fetal heart motion was associated with a spontaneous abortion in only 4.5% of the cases. However, the incidence of spontaneous abortion following fetal heart motion increased to 10% in women 36-39 years and 29% in women > or = 40 years of age. The presence of heart motion should not be considered a reassuring sign in the older woman. These data have implications regarding early embryology and the counselling of infertility patients.   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