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   2798篇
  免费   206篇
  国内免费   28篇
耳鼻咽喉   10篇
儿科学   70篇
妇产科学   58篇
基础医学   324篇
口腔科学   50篇
临床医学   345篇
内科学   668篇
皮肤病学   68篇
神经病学   275篇
特种医学   174篇
外科学   279篇
综合类   95篇
一般理论   1篇
预防医学   347篇
眼科学   56篇
药学   105篇
中国医学   18篇
肿瘤学   89篇
  2022年   14篇
  2021年   57篇
  2020年   27篇
  2019年   36篇
  2018年   59篇
  2017年   38篇
  2016年   54篇
  2015年   48篇
  2014年   57篇
  2013年   137篇
  2012年   124篇
  2011年   129篇
  2010年   97篇
  2009年   81篇
  2008年   92篇
  2007年   138篇
  2006年   105篇
  2005年   84篇
  2004年   80篇
  2003年   80篇
  2002年   72篇
  2001年   69篇
  2000年   53篇
  1999年   57篇
  1998年   63篇
  1997年   63篇
  1996年   53篇
  1995年   43篇
  1994年   46篇
  1993年   51篇
  1992年   41篇
  1991年   38篇
  1990年   37篇
  1989年   75篇
  1988年   46篇
  1987年   53篇
  1986年   31篇
  1985年   36篇
  1984年   23篇
  1983年   19篇
  1982年   22篇
  1981年   23篇
  1980年   25篇
  1979年   26篇
  1977年   23篇
  1972年   19篇
  1971年   13篇
  1968年   16篇
  1966年   16篇
  1941年   16篇
排序方式: 共有3032条查询结果,搜索用时 15 毫秒
1.
The ileocecal reservoir (Indiana pouch) is a large volume, low pressure continent reservoir well suited for urinary diversion. The mechanism of continence is believed to be the result of several factors, including the natural ileocecal valve resistance, resistance produced by the plication of the ileal segment and normal peristalsis of the ileum. We report the results of a video-urodynamic study in patients with an Indiana pouch, aimed at establishing the factors that contribute to continence and their relative significance. Video-urodynamic studies clearly demonstrate that continence in this type of urinary reservoir is dependent upon a synergism of the aforementioned factors in combination with the low intraluminal pressure of the detubularized bowel. Video-urodynamic studies offer an objective demonstration of the reservoir dynamics and its continence mechanisms, and provide an insight into the possible etiology of incontinence. Such studies also offer an objective means for critical comparison of the different continent urinary reservoirs.  相似文献   
2.
3.
Background. Extensive questioning of patients with a wide variety of skin disorders led to the impression that nocturnal overheating was probably an important factor in the initiation and the perpetuation of many skin disorders. Methods. In order to test the hypothesis, 12 “clean-skinned” subjects (6M/6F) aged 18 to 45 years were monitored electronically every 30 seconds during an 8 hour sleep period (2300 to 0700 hours), sleeping under a standard 10 tog duvet. Results. All the subjects were too hot by 3 to 4°C. All showed changes in their EEG patterns with reduced REM sleep, increased awakenings, and all showed changes in their sleep stage patterns. In addition, they all showed evidence of increased sweating in the “heat-sink” area. Conclusions. The mechanisms where by such changes could be implicated in the precipitation and perpetuation of skin disease are discussed. “Lifestyle” modification as a very effective, noninvasive, therapeutic regime is recommended. Further research along these lines would probably be very valuable and instructive.  相似文献   
4.
5.
Background The aim of the present study was to identify factors associated with the level of psychological distress reported by family carers of children with intellectual disability living in a large urban conurbation. Method Information was collected by postal questionnaire (or interview for family carers who did not have English as their first language) from the family carers of 408 children with intellectual disability (31% of all children within the area administratively identified as having an intellectual disability). Results Results indicated that 47% of primary carers scored above the threshold for psychological distress on the GHQ and that scoring above the threshold was strongly related to the emotional and behavioural needs of the index child and South‐Asian ethnicity and moderately associated with the severity of the child's delay in communication. Conclusions The rates of psychological distress (47% overall, 70% among South‐Asian carers) were markedly higher than that found in previous studies of carers supporting a child with intellectual disabilities. It is suggested that these elevated rates of psychological distress may be mediated by socio‐economic deprivation.  相似文献   
6.
7.
Ten thrombocytopenic patients (platelets < 10–24 × 10(9)/L) who were refractory to platelet transfusion were investigated for their responsiveness to staphylococcal protein A column therapy. Nine patients had previously been treated with steroids, intravenous immune globulin, and/or other forms of immunosuppressive therapy without improvement in their transfusion response. All patients were receiving multiple platelet transfusions without achieving 1-hour corrected count increments (CCIs) > or = 7500. Eight patients had antibodies that reacted with platelets and were directed against HLA class I antigens, ABO antigens, and/or platelet-specific alloantigens. Plasma (500-2000 mL) from each patient was passed over a protein A silica gel column and then returned to the patient. Patients received from 1 to 14 treatments. A positive response to protein A therapy was defined as at least a doubling of the pretreatment platelet count and/or two successive 10- to 120-minute posttransfusion CCIs > or = 7500. Following plasma treatments, 6 of 10 patients responded with daily platelet counts that averaged 48 +/− 11 × 10(9) per L as compared with counts of 16 +/− 7 × 10(9) per L (p < 0.0005) before treatment. Posttransfusion CCI values determined in four of these patients averaged 2480 +/− 810 and 10,010 +/− 3540 (p < 0.005) before and after treatment, respectively. In contrast, among the four unresponsive patients, platelet counts averaged 10 +/− 9 and 13 +/− 10 × 10(9) per L (p = NS), respectively, while posttransfusion CCIs were 700 +/− 1410 and 1520 +/− 2460 (p = NS), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
8.
Medial border of the perirenal space: CT and anatomic correlation   总被引:11,自引:0,他引:11  
  相似文献   
9.
The purpose of this study was to examine motor learning and retention given extensive practice in two fundamentally different movement sequences. One sequence was a memory-driven task (performing a series of whole body positions from memory) and the other a context-driven task (buttoning). Practice took place over 3 weeks, with performance measured weekly; retention was measured weekly for 3 weeks after practice. There were 7 people with Parkinson's disease (PD) and 7 age-matched neurologically healthy people who participated in this study. Both groups improved performance on both tasks with practice, with the majority of the change for the PD group occurring between 1 and 2 weeks of practice. Although those with PD did not necessarily perform as well as age-matched controls, they learned both sequences in a manner similar to age-matched controls, and exhibited retention across the 3-week retention interval. If people with PD are given sufficient practice they can learn and retain both memory-based and context-driven movement sequences as well as age-matched controls. The results provide support for maintaining physical activity and for intervention through movement therapy.  相似文献   
10.
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