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   1819篇
  免费   207篇
  国内免费   6篇
耳鼻咽喉   25篇
儿科学   36篇
妇产科学   32篇
基础医学   184篇
口腔科学   24篇
临床医学   198篇
内科学   358篇
皮肤病学   12篇
神经病学   153篇
特种医学   117篇
外科学   286篇
综合类   54篇
一般理论   4篇
预防医学   153篇
眼科学   41篇
药学   155篇
中国医学   1篇
肿瘤学   199篇
  2023年   17篇
  2022年   17篇
  2021年   38篇
  2020年   41篇
  2019年   31篇
  2018年   57篇
  2017年   39篇
  2016年   40篇
  2015年   58篇
  2014年   50篇
  2013年   77篇
  2012年   131篇
  2011年   106篇
  2010年   67篇
  2009年   61篇
  2008年   101篇
  2007年   87篇
  2006年   89篇
  2005年   71篇
  2004年   74篇
  2003年   58篇
  2002年   53篇
  2001年   37篇
  2000年   37篇
  1999年   28篇
  1998年   30篇
  1997年   32篇
  1996年   27篇
  1995年   32篇
  1994年   29篇
  1993年   16篇
  1992年   13篇
  1991年   19篇
  1990年   34篇
  1989年   26篇
  1988年   24篇
  1987年   25篇
  1986年   23篇
  1985年   13篇
  1984年   18篇
  1983年   13篇
  1980年   14篇
  1979年   10篇
  1978年   11篇
  1977年   12篇
  1976年   16篇
  1973年   12篇
  1972年   10篇
  1970年   17篇
  1968年   10篇
排序方式: 共有2032条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Evaluation of an on-line patient exposure meter in neuroradiology   总被引:1,自引:0,他引:1  
  相似文献   
6.
人体液中喷布洛尔及其代谢物的GC/MS分析   总被引:1,自引:0,他引:1  
用气相色谱一质谱联用(GC-MSD)系统分析方法检出了人尿中喷布洛尔的6个羟化代谢物,用Scp-Pak柱提取的方法检出了人血浆中的原型药物。并从分子结构上对此药物的代谢途径进行了研究。尿中提取和血中提取的回收率分别为90.83.%和85.88%,Gc-MSD的检测限为5pg。本方法适用于运动员兴奋剂的系统检查。  相似文献   
7.
The effects of transdermal nitrate (TN) (Transiderm-Nitro TTS, Geigy Pharmaceuticals, one 10 cm2 patch daily) and oral isosorbide dinitrate (ISDN) (Sorbitrate, Stuart Pharmaceuticals, 10 mg three times daily) were compared in a group of 20 patients with chronic stable angina pectoris. Treadmill exercise duration was prolonged from a median time of 365 s to 428 s after ISDN (P less than 0.05), but was unchanged after TN. The difference between the active treatments was not significant. Weekly consumption of glyceryl trinitrate (GTN) increased during treatment with TN from a median value of 5.5 to 6.3 (P less than 0.05). A decrease was observed after ISDN (7.8 to 3.9, P = NS), and the difference between the drugs was significant (P less than 0.01). Systolic arterial pressure was significantly lower during the ISDN than during the TN treatment period in both the supine (135 +/- 5 vs 128 +/- 5 mm Hg; P less than 0.05) and standing positions (134 +/- 5 vs 122 +/- 5 mm Hg; P less than 0.05). No change in weekly attack rate, the degree of ST depression at angina on treadmill testing, or the number of episodes of ST depression recorded during a 24 h period by Holter monitoring was observed after either drug. In this study, an antianginal effect was demonstrated for ISDN but not for TN. It is suggested that the dose of TN may have been inadequate to demonstrate such an effect, and further studies using a higher dose schedule will be required.  相似文献   
8.
9.
Classification and grouping of clinical data into defined categories or hierarchies is difficult in intensive care practice. Diagnosis-related groups are used to categorise patients on the basis of diagnosis. However, this approach may not be applicable to intensive care where there is wide heterogeneity within diagnostic groups. Classification tree analysis uses selected independent variables to group patients according to a dependent variable in a way that reduces variation. In this study, the influence of three easily identified patient attributes on their length of intensive care unit stay was explored using classification analysis. Two thousand five hundred and forty-five critically ill patients from three hospitals were classified into groups so that the variation in length of stay within each group was minimised. In 23 out of 39 terminal groups, the interquartile range of the length of stay was ≤ 3 days.  相似文献   
10.
X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG repeat expansion in the first exon of the androgen receptor (AR) gene. Disease-associated alleles (37-66 CAGs) change in length when transmitted from parents to offspring, with a significantly greater tendency to shift size when inherited paternally. As transgenic mice carrying human AR cDNAs with 45 and 66 CAG repeats do not display repeat instability, we attempted to model trinucleotide repeat instability by generating transgenic mice with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions in their genomic context. Studies of independent lines of AR YAC transgenic mice with CAG 45 alleles reveal intergenerational instability at an overall rate of approximately 10%. We also find that the 45 CAG repeat tracts are significantly more unstable with maternal transmission and as the transmitting mother ages. Of all the CAG/CTG repeat transgenic mice produced to date the AR YAC CAG 45 mice are unstable with the smallest trinucleotide repeat mutations, suggesting that the length threshold for repeat instability in the mouse may be lowered by including the appropriate flanking human DNA sequences. By sequence-tagged site content analysis and long range mapping we determined that one unstable transgenic line has integrated an approximately 70 kb segment of the AR locus due to fragmentation of the AR YAC. Identification of the cis - acting elements that permit CAG tract instability and the trans -acting factors that modulate repeat instability in the AR YAC CAG 45 mice may provide insights into the molecular basis of trinucleotide repeat instability in humans.   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