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   1418498篇
  免费   114329篇
  国内免费   3346篇
耳鼻咽喉   18407篇
儿科学   46960篇
妇产科学   41248篇
基础医学   201925篇
口腔科学   37806篇
临床医学   127073篇
内科学   285742篇
皮肤病学   33563篇
神经病学   117679篇
特种医学   53979篇
外国民族医学   464篇
外科学   211173篇
综合类   32965篇
现状与发展   3篇
一般理论   505篇
预防医学   111044篇
眼科学   31631篇
药学   99031篇
  1篇
中国医学   3355篇
肿瘤学   81619篇
  2021年   11187篇
  2019年   11982篇
  2018年   16918篇
  2017年   12915篇
  2016年   14532篇
  2015年   16294篇
  2014年   22886篇
  2013年   33823篇
  2012年   46007篇
  2011年   48595篇
  2010年   28512篇
  2009年   27309篇
  2008年   44721篇
  2007年   47267篇
  2006年   47783篇
  2005年   46288篇
  2004年   44124篇
  2003年   41995篇
  2002年   40524篇
  2001年   73046篇
  2000年   74571篇
  1999年   61606篇
  1998年   17042篇
  1997年   15463篇
  1996年   15636篇
  1995年   14830篇
  1994年   13434篇
  1993年   12623篇
  1992年   45875篇
  1991年   43508篇
  1990年   41511篇
  1989年   39564篇
  1988年   36189篇
  1987年   35371篇
  1986年   32886篇
  1985年   31312篇
  1984年   23860篇
  1983年   20053篇
  1982年   12235篇
  1981年   10796篇
  1979年   20714篇
  1978年   14586篇
  1977年   12092篇
  1976年   11369篇
  1975年   11627篇
  1974年   13997篇
  1973年   13540篇
  1972年   12643篇
  1971年   11473篇
  1970年   10914篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
OBJECTIVE: Tumors arising within augmentation cystoplasties are aggressive, have poor prognosis and the majority are not detected at follow-up cystoscopy. Genetic changes in tumors precede morphological abnormalities. Therefore, the aim of this study was to investigate whether genetic abnormalities detected by comparative genomic hybridization (CGH) could be used to identify those patients with augmentation cystoplasties at increased risk of tumorigenesis. METHODS: Bladder biopsy samples were obtained from 16 augmentation cystoplasty patients both distant from and near to the enterovesical anastomosis. CGH was used to detect genetic abnormalities in DNA extracted from the biopsies, archival specimens of two augmentation cystoplasties and two de novo bladder adenocarcinomas. RESULTS: A greater number of amplifications on 2p, 3q, 8q, 9p, 17p, 18pq and 20pq, were observed in bladder biopsies obtained near to the enterovesical anastomosis compared to those taken distant to the suture line. CGH of archival augmentation cystoplasty tumor DNA indicated abnormalities at several loci with amplifications at 2q, 5q, 10p and 21pq, while deletions occurred at 5p and 16p. CONCLUSIONS: The results of this study suggest that the urothelium adjacent to the bladder and/or bowel anastomosis in augmentation cystoplasties is genetically unstable. Furthermore, longitudinal studies are required to establish whether or not patients exhibiting genetic instability following augmentation cystoplasty are at greater risk of developing tumors than those with genetically stable epithelia.  相似文献   
993.
994.
995.
996.
Conclusions  Noninvasive imaging of neurohumoral upregulation in remodeled myocardium suggests that an imaging strategy can be developed for predicting the rate of remodeling and likelihood of HF development. This should allow a more judicious use of neurohumoral antagonists especially in subjects who do not have manifest HF.74 In others specific targeted imaging may allow timely selection of individualized treatment strategies and ensure optimization of therapeutic intervention. Similar to ACE and AII receptors, multiple other targets in the hormonal cascades can identify the likelihood of adverse and favorable remodeling.74  相似文献   
997.
998.
999.
Cytokines play a pivotal role in the pathogenesis of degenerative joint disease but also in inflammatory conditions as well as osteoarthritis (OA) and rheumatoid arthritis (RA). A key role is attributed to interleukin-1 and tumor necrosis factor-α. Certain cytokines that can inhibit the activity of catabolic cytokines have great therapeutic potential and are currently being investigated in numerous clinical studies. Available scientific findings indicate that proinflammatory cytokines stimulate cartilage breakdown and blockade of these cytokines can protect the cartilage.  相似文献   
1000.
Lesley C Dinwiddie 《Nephrology nursing journal》2004,31(6):653-60, 671; quiz 661-2
Vascular access is the leading cause of morbidity in the hemodialysis patient population. Arteriovenous fistulas (AVFs) have the lowest complication rate while catheters have the highest. Though significant effort is being made to increase the number of AVFs and lower the number of catheters, annual data show that the number of catheters is increasing. To improve vascular access-related patient outcomes, catheter dysfunction needs to be managed by a vascular access team using the CQI process that begins with a comprehensive algorithm for treatment.  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