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   4380564篇
  免费   341245篇
  国内免费   14772篇
耳鼻咽喉   60542篇
儿科学   140039篇
妇产科学   114900篇
基础医学   669476篇
口腔科学   118572篇
临床医学   400077篇
内科学   794392篇
皮肤病学   108047篇
神经病学   370214篇
特种医学   170115篇
外国民族医学   758篇
外科学   659170篇
综合类   121780篇
现状与发展   24篇
一般理论   2658篇
预防医学   362880篇
眼科学   101586篇
药学   309495篇
  28篇
中国医学   11970篇
肿瘤学   219858篇
  2021年   56320篇
  2020年   35951篇
  2019年   58969篇
  2018年   74647篇
  2017年   57207篇
  2016年   63361篇
  2015年   76279篇
  2014年   110556篇
  2013年   176334篇
  2012年   125933篇
  2011年   130879篇
  2010年   126500篇
  2009年   128068篇
  2008年   116773篇
  2007年   124240篇
  2006年   133066篇
  2005年   127086篇
  2004年   128529篇
  2003年   118543篇
  2002年   107662篇
  2001年   167360篇
  2000年   162374篇
  1999年   149028篇
  1998年   71833篇
  1997年   67733篇
  1996年   65762篇
  1995年   61144篇
  1994年   55077篇
  1993年   51121篇
  1992年   106870篇
  1991年   101618篇
  1990年   97463篇
  1989年   95052篇
  1988年   87374篇
  1987年   85536篇
  1986年   80395篇
  1985年   78595篇
  1984年   65553篇
  1983年   58344篇
  1982年   47273篇
  1981年   43929篇
  1980年   41133篇
  1979年   55245篇
  1978年   44874篇
  1977年   40073篇
  1976年   36960篇
  1975年   36904篇
  1974年   39728篇
  1973年   37857篇
  1972年   35462篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
151.
152.
We have carried out a prospective randomised, single blind clinical trial to investigate the effect of continuous passive motion on range of knee flexion, lack of extension, pain levels and analgesic use after total knee replacement surgery. 85 subjects were randomly allocated to control or study group. All subjects followed the existing rehabilitation protocol, which permits immediate active range of motion exercises and mobilisation with the study group using continuous passive motion for 1 h, twice a day. Outcome measures employed were range of motion, pain assessed on a visual analogue scale and analgesic use according to the WHO ladder. Blinded evaluation was carried out preoperatively, at time of discharge from hospital, 6 weeks, 6 and 12 months postoperation. No significant difference was observed between groups at all time intervals for each outcome variable using Wilcoxon Rank sum tests. The results substantiate previous findings that short duration continuous passive motion following total knee arthroplasty does not influence outcome of range of motion or reported pain.  相似文献   
153.
Fast CT-PRESS-based spiral chemical shift imaging at 3 Tesla.   总被引:2,自引:0,他引:2  
A new sequence is presented that combines constant-time point-resolved spectroscopy (CT-PRESS) with fast spiral chemical shift imaging. It allows the acquisition of multivoxel spectra without line splitting with a minimum total measurement time of less than 5 min for a field of view of 24 cm and a nominal 1.5x1.5-cm2 in-plane resolution. Measurements were performed with 17 CS encoding steps in t1 (Deltat1=12.8 ms) and an average echo time of 151 ms, which was determined by simulating the CT-PRESS experiment for the spin systems of glutamate (Glu) and myo-inositol (mI). Signals from N-acetyl-aspartate, total creatine, choline-containing compounds (Cho), Glu, and mI were detected in a healthy volunteer with no or only minor baseline distortions within 14 min on a 3 T MR scanner.  相似文献   
154.
155.
156.
157.
158.
BACKGROUND: The laparoscopic resection of rectal cancer shows morbidity and oncological safety comparable to the open approach, but morbidity increases after conversion to open resection. No oncological long-term results are available for the latter patients. METHODS: From 01/01/2000-31/12/2002, patients with curatively resected rectal cancer enrolled in a observational study were evaluated for morbidity, mortality, tumor- and local recurrence rate, paying attention to patients with conversion from laparoscopic to open resection. RESULTS: 237 (3.3%) of 7,189 patients underwent laparoscopic resection (ITT). These patients showed significantly more T1/2 tumors (P<0.001) in earlier UICC stages (P<0.001) than open resected patients. 35 (14.8%) of 237 laparoscopic procedures were converted. Compared with patients receiving complete laparoscopic or open resection, these patients showed significantly higher frequencies of intraoperative (P<0.001) and general postoperative complications (P=0.003) as well as the highest overall morbidity (P=0.031). After a median follow-up of 30.1 months, the highest 5-year local recurrence rate was found in the converted group (16.0%). The laparoscopically resected patients showed a local recurrence rate of 3.3%, patients with open resection of 12.4% (P=0.082). The disease-free survival rate did not differ between the groups (P=0.585). CONCLUSION: Laparoscopic resection of rectal cancer provides oncological results similar to open resection. After conversion, the short and oncological long-term outcomes were worse. Considering a conversion rate of 15%, only a strict indication for the laparoscopic approach can be allowed, and laparoscopic resection should be performed at centers.  相似文献   
159.
160.
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