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   12117篇
  免费   893篇
  国内免费   35篇
耳鼻咽喉   78篇
儿科学   433篇
妇产科学   200篇
基础医学   1455篇
口腔科学   253篇
临床医学   1153篇
内科学   2346篇
皮肤病学   119篇
神经病学   1131篇
特种医学   404篇
外科学   1876篇
综合类   279篇
一般理论   9篇
预防医学   1141篇
眼科学   297篇
药学   948篇
中国医学   49篇
肿瘤学   874篇
  2023年   53篇
  2022年   47篇
  2021年   258篇
  2020年   156篇
  2019年   274篇
  2018年   273篇
  2017年   209篇
  2016年   220篇
  2015年   239篇
  2014年   401篇
  2013年   528篇
  2012年   822篇
  2011年   880篇
  2010年   462篇
  2009年   445篇
  2008年   738篇
  2007年   902篇
  2006年   827篇
  2005年   816篇
  2004年   752篇
  2003年   709篇
  2002年   636篇
  2001年   134篇
  2000年   107篇
  1999年   119篇
  1998年   134篇
  1997年   127篇
  1996年   100篇
  1995年   92篇
  1994年   81篇
  1993年   85篇
  1992年   73篇
  1991年   51篇
  1990年   52篇
  1989年   63篇
  1988年   60篇
  1987年   51篇
  1986年   51篇
  1985年   62篇
  1984年   61篇
  1983年   55篇
  1982年   62篇
  1981年   58篇
  1980年   53篇
  1979年   39篇
  1978年   38篇
  1977年   28篇
  1975年   27篇
  1973年   37篇
  1972年   34篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
This paper presents a case for careful consideration of theory in planning to implement evidence-based practices into clinical care. As described, theory should be tightly linked to strategic planning through careful choice or creation of an implementation framework. Strategies should be linked to specific interventions and/or intervention components to be implemented, and the choice of tools should match the interventions and overall strategy, linking back to the original theory and framework. The thesis advanced is that in most studies where there is an attempt to implement planned change in clinical processes, theory is used loosely. An example of linking theory to intervention design is presented from a Mental Health Quality Enhancement Research Initiative effort to increase appropriate use of antipsychotic medication among patients with schizophrenia in the Veterans Health Administration.  相似文献   
7.
8.
Reconstitution of the nasal scaffolding with maintainence of soft tissue proportions either following severe facial trauma or as a sequela to aesthetic rhinoplasty misadventures frequently is best achieved using the stability afforded by bone grafts. Split cranial bone grafts offer many advantages and may be the donor site of choice, and may even allow such surgery to be performed on an outpatient basis in some cases. The use of miniplate or screw osteosynthesis, now commonly accepted as a superior technique in craniomaxillofacial procedures, may simplify fixation of these calvarial nasal bone grafts with an apparent decrease in the risk of resorption.  相似文献   
9.
BACKGROUND: Purinergic receptors are cell-surface molecules that bind extracellular nucleotides, notably ATP. The P2X family includes seven nonselective ion channels with one member, P2X(7), implicated in cytolytic pore formation and cell death. MATERIALS AND METHODS: We sought P2X(7) expression in mouse nephrogenesis and cpk/cpk renal cyst growth, conditions in which both proliferation and apoptosis are prominent. RESULTS: P2X(7) immunolocalized to condensed metanephric mesenchyme: both proliferation and apoptosis were detected in this compartment, assessed by proliferating cell nuclear antigen expression and propidium iodide-stained pyknotic nuclei respectively. Later in nephrogenesis, P2X(7) was detected in collecting ducts, a pattern persisting to maturity. A mesenchymal to epithelial shift of P2X(7) expression was also documented in ureter development. In cpk/cpk kidneys, P2X(7)-expressing collecting duct cysts dominated histology from two weeks until four weeks after birth, when animals die from uremia. In polycystic kidneys pyknotic nuclei were rarely identified in P2X(7)-expressing epithelia, but were detected between cysts, consistent with a non-apoptotic role for P2X(7) in cyst enlargement. CONCLUSION: P2X(7) is expressed during normal nephrogenesis and in a model of congenital polycystic kidney disease. Further experiments are necessary to define possible functions of P2X(7) in these settings.  相似文献   
10.
PURPOSE: A role for estrogens in determining lung cancer risk and prognosis is suggested by reported sex differences in susceptibility and survival. Archival lung tissue was evaluated for the presence of nuclear estrogen receptor (ER)-alpha and ER-beta and the relationship between ER status, subject characteristics, and survival. EXPERIMENTAL DESIGN: Paraffin-embedded lung tumor samples were obtained from 214 women and 64 men from two population-based, case-control studies as were 10 normal lung autopsy samples from patients without cancer. Nuclear ER-alpha and ER-beta expression was determined by immunohistochemistry. Logistic regression was used to identify factors associated with ER positivity and Cox proportional hazards models were used to measure survival differences by ER status. RESULTS: Neither tumor (0 of 94) nor normal (0 of 10) lung tissue stained positive for ER-alpha. Nuclear ER-beta positivity was present in 61% of tumor tissue samples (170 of 278; 70.3% in men and 58.3% in women) and 20% of normal tissue samples (2 of 10; P = 0.01). In multivariate analyses, females were 46% less likely to have ER-beta-positive tumors than males (odds ratio, 0.54; 95% confidence interval, 0.27-1.08). This relationship was stronger and statistically significant in adenocarcinomas (odds ratio, 0.40; 95% confidence interval, 0.18-0.89). Women with ER-beta-positive tumors had a nonsignificant 73% (P = 0.1) increase in mortality, whereas men with ER-beta-positive tumors had a significant 55% (P = 0.04) reduction in mortality compared with those with ER-beta-negative tumors. CONCLUSIONS: This study suggests differential expression by sex and influence on survival in men of nuclear ER-beta in lung cancer, particularly in adenocarcinomas.  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