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   1164篇
  免费   352篇
  国内免费   12篇
耳鼻咽喉   5篇
儿科学   39篇
妇产科学   92篇
基础医学   39篇
口腔科学   6篇
临床医学   718篇
内科学   197篇
皮肤病学   11篇
神经病学   70篇
特种医学   47篇
外科学   106篇
综合类   18篇
预防医学   102篇
眼科学   1篇
药学   45篇
中国医学   1篇
肿瘤学   31篇
  2023年   4篇
  2021年   10篇
  2020年   7篇
  2019年   12篇
  2018年   70篇
  2017年   103篇
  2016年   115篇
  2015年   102篇
  2014年   89篇
  2013年   126篇
  2012年   55篇
  2011年   56篇
  2010年   67篇
  2009年   95篇
  2008年   72篇
  2007年   67篇
  2006年   53篇
  2005年   52篇
  2004年   65篇
  2003年   30篇
  2002年   33篇
  2001年   22篇
  2000年   21篇
  1999年   11篇
  1998年   15篇
  1997年   24篇
  1996年   19篇
  1995年   10篇
  1994年   13篇
  1993年   10篇
  1992年   9篇
  1991年   6篇
  1990年   4篇
  1989年   7篇
  1988年   5篇
  1987年   6篇
  1986年   3篇
  1985年   8篇
  1984年   5篇
  1983年   4篇
  1982年   4篇
  1977年   3篇
  1975年   3篇
  1974年   3篇
  1973年   4篇
  1971年   6篇
  1969年   2篇
  1968年   2篇
  1967年   2篇
  1965年   2篇
排序方式: 共有1528条查询结果,搜索用时 23 毫秒
81.
82.
83.
84.
85.
86.
The purpose of the study was to investigate the biomechanical effects of different types of braces that are used in the treatment of patients with epicondylitis radialis. Vibration and acceleration of the forearm and the elbow were measured with sensors taped to defined anatomic points on the skin surface. The impact-induced vibration of the racket-arm system was analyzed while the subjects were playing tennis. Different designed brace systems were investigated with respect to acceleration amplitudes and acceleration integrals. Clasp-based brace systems showed a slight reduction of acceleration amplitudes (-6%) and acceleration integrals (-8%). Braces with pads at the lateral epicondyle reduced acceleration amplitudes by 20% and acceleration integrals by 22%. Braces with pads placed at the forearm showed the highest reduction of acceleration amplitudes (-46%) and acceleration integrals (-42%). Overload of the wrist extensors, which is considered to be a major pathogenic factor in lateral epicondylitis, can be reduced by braces. There is a significant difference in the effects among different biomechanical principles of braces.  相似文献   
87.
INTRODUCTION: The Deletion (D) rather than Insertion (I) variant of the angiotensin-converting enzyme (ACE) gene is associated with higher circulating ACE activity. Meanwhile, coronary risk rises with the menstrual nadir in oestrogen levels, exogenous oestrogen reduces serum ACE activity (with a greater reduction the higher the baseline ACE activity), and pharmacological reduction in ACE activity is cardioprotective. Alterations in coronary risk associated with the menstrual cycle may thus be mediated through (genotype-dependent) changes in ACE activity. We have examined this hypothesis. MATERIALS AND METHODS: Twenty-three healthy female subjects (12 II, 11 DD genotype) were studied. None were taking oral contraceptive agents. Blood was assayed for oestrogen, follicle stimulating hormone (FSH), luteinising hormone (LH), progesterone and ACE activity every three days throughout their menstrual cycle. RESULTS: ACE activity was unrelated to oestrogen, FSH or LH during the menstrual cycle, irrespective of ACE genotype. CONCLUSIONS: The increase in myocardial ischaemia during low oestrogen phases of the menstrual cycle does not appear mediated through a fall in serum ACE activity.  相似文献   
88.
Background: Forty percent of patients with colorectal cancer develop mutations in the K-ras gene.Objective: Our objective was to evaluate whether the presence of c-K-ras gene mutations is a useful tumor-response marker in patients with locally advanced rectal cancer treated with preoperative chemoradiotherapy.Material and Methods: Thirty seven patients with locally advanced rectal cancer were treated with preoperative chemoradiotherapy. Four to six weeks later, surgery was performed. Specimens were classified according to the UICC-AJC classification. A segment of the tumor was obtained to analyze specific c-K-ras gene mutations. Restriction fragment length polymorphism (RFLP) and single strand confirmation polymorphism (SSCP) techniques were used with a set of probes to detect specific c-K-ras mutations in codons 12, 13, and 61. The 37 patients were divided into Group A (with mutations) and Group B (without mutations).Results: All 37 patients completed the scheduled treatment. Group A consisted of 12 patients, whose tumors were classified and specific c-K-ras mutations were located as follows: eight in codon 12, two in codon 13, and one in codon 61. Group B consisted of 25 patients. The tumors were classified and there were more early-stage tumors in Group A, whereas in Group B there were more advanced-stage tumors (P 5 .05, respectively). The mean follow-up was 36.2 6 18.3 months. All Group A patients survived, whereas 8 of the 25 patients in Group B died due to progressive metastatic disease. Survival in Group A was 100%, whereas in Group B it was 59% (P 5 .03).Conclusions: The presence of specific c-K-ras mutations is an indicator of tumor response in patients with locally advanced rectal cancer treated with preoperative chemoradiotherapy and surgery. Therefore, responding patients may be more amenable to less radical surgical procedures based on c-K-ras mutations.  相似文献   
89.
90.
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