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   717篇
  免费   43篇
  国内免费   13篇
儿科学   48篇
妇产科学   36篇
基础医学   78篇
口腔科学   15篇
临床医学   47篇
内科学   106篇
皮肤病学   6篇
神经病学   22篇
特种医学   75篇
外科学   72篇
综合类   22篇
预防医学   114篇
眼科学   18篇
药学   37篇
中国医学   3篇
肿瘤学   74篇
  2022年   5篇
  2021年   9篇
  2020年   11篇
  2019年   7篇
  2018年   9篇
  2017年   9篇
  2016年   9篇
  2015年   13篇
  2014年   15篇
  2013年   19篇
  2012年   51篇
  2011年   44篇
  2010年   31篇
  2009年   32篇
  2008年   27篇
  2007年   28篇
  2006年   30篇
  2005年   17篇
  2004年   21篇
  2003年   12篇
  2002年   21篇
  2001年   10篇
  2000年   10篇
  1999年   12篇
  1998年   29篇
  1997年   20篇
  1996年   49篇
  1995年   51篇
  1994年   15篇
  1993年   10篇
  1992年   5篇
  1991年   8篇
  1990年   5篇
  1989年   14篇
  1988年   10篇
  1987年   17篇
  1986年   12篇
  1985年   13篇
  1983年   5篇
  1982年   8篇
  1981年   5篇
  1980年   5篇
  1979年   4篇
  1978年   3篇
  1977年   4篇
  1976年   5篇
  1975年   5篇
  1968年   5篇
  1967年   2篇
  1966年   2篇
排序方式: 共有773条查询结果,搜索用时 15 毫秒
1.
Reports of a dramatic decrease in tumor recurrence and regression of muscle invasive disease with oral bacillus Calmette-Guerin prompted us to conduct a randomized prospective comparison of oral bacillus Calmette-Guerin with the standard intravesical plus percutaneous therapy. Oral therapy consisted of 200 mg. Tice bacillus Calmette-Guerin 3 times each week. Intravesical and percutaneous Tice bacillus Calmette-Guerin at a dose of 50 mg. was given weekly for 6 weeks, at 8, 10 and 12 weeks, then at 6 months and every 6 months thereafter. Minimal side effects confirmed the safety of oral bacillus Calmette-Guerin. Tumor recurrence was documented in 21 of 33 oral bacillus Calmette-Guerin patients (64%) and 18 of 55 (33%) who received intravesical plus percutaneous therapy (p less than 0.002, chi-square test). We were unable to demonstrate any antitumor activity of oral bacillus Calmette-Guerin in this study.  相似文献   
2.
Winkler  ML; Olsen  WL; Mills  TC; Kaufman  L 《Radiology》1987,165(1):203-207
Two fast magnetic resonance (MR) imaging techniques, advanced Fourier and partial-flip imaging, were used at 0.35 T to examine 21 patients with suspected intracranial lesions; the results were quantitatively compared with a conventional spin-echo study. Both of the fast MR techniques yielded a fourfold reduction in imaging time per section. The advanced Fourier sequence showed contrast that was identical to the conventional spin-echo study with signal-to-noise ratios of 58% and 57% for the first and second echoes, respectively. The partial-flip sequence showed a contrast of 109% and 57% for lesions versus substantia alba, and 107% and 78% for substantia grisea versus substantia alba relative to the first and second echoes of the conventional spin-echo study. The partial-flip sequence was particularly sensitive to magnetic susceptibility; this produced artifacts that may undermine the usefulness of partial flip for routine screening in certain parts of the brain. However, this susceptibility significantly improved the detection of intracranial hemorrhage when compared with the spin-echo sequence, particularly when combined with phase mapping of the partial-flip study.  相似文献   
3.
The Bethlem myopathy is a rare autosomal dominant proximal myopathy characterized by early childhood onset and joint contractures. Evidence for linkage and genetic heterogeneity has been established, with the majority of families linked to 21q22.3 and one large family linked to 2q37, implicating the three type VI collagen subunit genes, COL6A1 (chromosome 21), COL6A2 (chromosome 21) and COL6A3 (chromosome 2) as candidate genes. Mutations of the invariant glycine residues in the triple-helical domain-coding region of COL6A1 and COL6A2 have been reported previously in the chromosome 21-linked families. We report here the identification of a G-->A mutation in the N-terminal globular domain-coding region of COL6A3 in a large American pedigree (19 affected, 12 unaffected), leading to the substitution of glycine by glutamic acid in the N2 motif, which is homologous to the type A domains of the von Willebrand factor. This mutation segregated to all affected family members, to no unaffected family members, and was not identified in 338 unrelated Caucasian control chromosomes. Thus mutations in either the triple-helical domain or the globular domain of type VI collagen appear to cause Bethlem myopathy.   相似文献   
4.
5.
The Ritz-Carlton Hotel Company won the Malcolm Baldrige National Quality Award in 1992. One key to its success is its strategic planning process. In this second part of a two-part article, Stephen Shriver concludes his review of the Ritz-Carlton's approach to strategic planning. Shriver begins by outlining some key steps in plan development and goes on to describe how the Ritz-Carlton disseminates, implements, and evaluates the plan.  相似文献   
6.
0 引言为了克服离子选择电极(ISE)法的微量电位信号极易受环境温度变化及电子噪声的干扰问题,该仪器采用了参考电极,把参考电极与其测定电极装在同一测量室内,保持其相同的物理环境,使干扰源对所有电极的影响相同. 以内参液作为参考电极的测量对象,测得一个参考电极电位值,再测样品的电极电位值,二者相抵就消除了所叠加的干扰信号.  相似文献   
7.
8.
9.
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