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   5463篇
  免费   451篇
  国内免费   13篇
耳鼻咽喉   112篇
儿科学   222篇
妇产科学   102篇
基础医学   696篇
口腔科学   123篇
临床医学   538篇
内科学   1062篇
皮肤病学   70篇
神经病学   404篇
特种医学   408篇
外国民族医学   1篇
外科学   811篇
综合类   134篇
一般理论   2篇
预防医学   440篇
眼科学   56篇
药学   495篇
中国医学   1篇
肿瘤学   250篇
  2021年   59篇
  2020年   41篇
  2019年   65篇
  2018年   101篇
  2017年   80篇
  2016年   101篇
  2015年   99篇
  2014年   149篇
  2013年   183篇
  2012年   272篇
  2011年   256篇
  2010年   170篇
  2009年   187篇
  2008年   252篇
  2007年   267篇
  2006年   230篇
  2005年   216篇
  2004年   180篇
  2003年   165篇
  2002年   177篇
  2001年   152篇
  2000年   168篇
  1999年   128篇
  1998年   92篇
  1997年   93篇
  1996年   91篇
  1995年   76篇
  1994年   71篇
  1993年   79篇
  1992年   103篇
  1991年   94篇
  1990年   76篇
  1989年   118篇
  1988年   107篇
  1987年   127篇
  1986年   106篇
  1985年   91篇
  1984年   61篇
  1983年   67篇
  1982年   48篇
  1981年   45篇
  1980年   60篇
  1979年   54篇
  1978年   51篇
  1977年   48篇
  1976年   38篇
  1975年   57篇
  1974年   39篇
  1973年   37篇
  1970年   36篇
排序方式: 共有5927条查询结果,搜索用时 46 毫秒
1.
2.
In a retrospective study, 217 patients with conservatively treated adolescent idiopathic scoliosis (AIS) were investigated. Forty-nine cases were operated and 168 were treated only conservatively and had been out of the brace for at least 4 years at the time of the investigation. The progression between cessation of brace treatment and follow-up (a mean of 6.9 years later) was 5.1 degrees. Almost all progression (4.5 degrees) occurred within 2 years of the end of weaning, however. The incidence of failure with regard to the length of follow-up was also studied. A follow-up of 2 years was sufficient to predict with great accuracy (97%) all incidences of failure.  相似文献   
3.
The clinical profile of tropical spastic paraparesis (TSP), described in scattered tropical and subtropical territories over the past 30 years, has been more clearly defined since the discovery of its direct association with human T lymphotropic virus type 1 (HTLV-1). A chronic disease of adults, commoner in women, it usually presents as a progressive spastic paraparesis with sphincter disturbance, sometimes with backache and lower limb sensory disorder. Most cases are chair-bound within 10 years. Histology reveals a chronic lymphocytic meningomyelopathy, predominantly in the spinal cord, together with long tract demyelination and hyalinoid thickening of the media and adventitia of small blood vessels. Geographical areas of high prevalence of TSP are known in the Caribbean, South America, South Africa, southern Japan, the Seychelles and probably in India, and it is sparsely endemic elsewhere. The virus appears to exist within lymphocytes for long periods. Vertical transmission occurs postnatally, and sexual and transfusion infection are also recognized, but much remains to be clarified regarding its pathogenesis and epidemiology.  相似文献   
4.
Interest in inguinal hernia surgery has increased significantly with the introduction of new operating techniques during the past decade. This multicenter study compared short-term results in patients treated by the laparoscopic transabdominal preperitoneal patch technique (TAPP; n=518) and the Shouldice technique (n=524). We evaluated demographics, operative data, complications, hospital stay, postoperative pain, use of analgesics, functional status, sick leave, and complaints up to 3 months postoperatively. The median operating time was shorter in the Shouldice group (55 vs. 65 min), but there were no significant differences in complication rates, and major complications were rare. The hospital stay was 1 day or less in over 98% of cases in both groups, but more operations were performed on outpatient basis in the Shouldice group. In the TAPP group postoperative pain and analgesic consumption were less, postoperative functional status was better, and sick leave was shorter (10 vs. 14 days). These results show that the two methods are equally safe and have few major complications. The TAPP operation is associated with less postoperative pain, better postoperative functional status, and shorter sick leave, but at the price of a longer operating time. Electronic Publication  相似文献   
5.
6.
7.
Head movement presents a continuing problem in PET studies. Head restraint minimizes movement but is unreliable, resulting in the need to develop alternative strategies. These include frame-by-frame (FBF) realignment or use of motion tracking (MT) during the scan to realign PET acquisition data. Here we present a comparative analysis of these 2 methods of motion correction. METHODS: Eight volunteers were examined at rest using (11)C-raclopride PET with the radioligand administered as a bolus followed by constant infusion to achieve steady state. Binding potential (BP) was estimated using the ratio method during 2 periods of the scan at steady state. Head movement was compensated by using coregistration between frames (FBF) and 3 methods using MT measurements of head position acquired with a commercially available optical tracking system. RESULTS: All methods of realignment improved test-retest reliability and noise characteristics of the raw data, with important consequences for the power to detect small changes in radiotracer binding, and the potential to reduce false-positive and false-negative results. MT methods were superior to FBF realignment using coregistration on some indices. CONCLUSION: Such methods have considerable potential to improve the reliability of PET data with important implications for the numbers of volunteers required to test hypotheses.  相似文献   
8.
9.
10.
Conventional risk factors have very low predictive power in identifying haemodialysis patients at high risk of vascular accidents. A role for apolipoprotein E isotypes was looked for in a small, but rigorously defined, cohort of longterm haemodialysis patients. In individuals with high vascular risk, as identified by higher common carotid intima/media thickness, we found an excess of apolipoprotein E4 alleles. This preliminary result requires confirmation in large patient cohorts.   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