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   1361794篇
  免费   96965篇
  国内免费   4898篇
耳鼻咽喉   19871篇
儿科学   40425篇
妇产科学   38892篇
基础医学   190243篇
口腔科学   40220篇
临床医学   116260篇
内科学   265998篇
皮肤病学   30425篇
神经病学   107764篇
特种医学   54866篇
外国民族医学   453篇
外科学   210905篇
综合类   35756篇
现状与发展   18篇
一般理论   440篇
预防医学   93856篇
眼科学   32024篇
药学   102779篇
  39篇
中国医学   4670篇
肿瘤学   77753篇
  2018年   12756篇
  2016年   11458篇
  2015年   13104篇
  2014年   18300篇
  2013年   26649篇
  2012年   35027篇
  2011年   37012篇
  2010年   22081篇
  2009年   21270篇
  2008年   34822篇
  2007年   37927篇
  2006年   38470篇
  2005年   37179篇
  2004年   35848篇
  2003年   34875篇
  2002年   34323篇
  2001年   64170篇
  2000年   65875篇
  1999年   55937篇
  1998年   15010篇
  1997年   13825篇
  1996年   13178篇
  1995年   12472篇
  1994年   11687篇
  1992年   42887篇
  1991年   41409篇
  1990年   40620篇
  1989年   39609篇
  1988年   37035篇
  1987年   36462篇
  1986年   34926篇
  1985年   33123篇
  1984年   24839篇
  1983年   21060篇
  1982年   12667篇
  1981年   11577篇
  1979年   23929篇
  1978年   17071篇
  1977年   14834篇
  1976年   13386篇
  1975年   15267篇
  1974年   18081篇
  1973年   17560篇
  1972年   16812篇
  1971年   15717篇
  1970年   14915篇
  1969年   14346篇
  1968年   13461篇
  1967年   12015篇
  1966年   11258篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Abstract Chorea is a rare complication of polycythaemia vera. Polycythaemic chorea occurs predominantly in females and usually in generalised form. We present a 66-year-old woman with acute onset hemichorea-ballism with no vascular pathology in the basal ganglia region. A clear relationship was observed between the onset of chorea and worsening of haematological parameters in the patient. After repeated phlebotomies the patient's clinical status was improved. Polycythaemic chorea must be considered, especially in the elderly, as early diagnosis leads to effective treatment and prevention of complications.  相似文献   
92.
93.
A new semi-empirical formula for the evaluation of (n,(3)He) reaction cross-sections at the energy of 14.6 and 20 MeV is presented. Formula was derived using the analytical expression for the evaluation of the (3)He spectrum within the frame of pre-equilibrium exciton model. The systematics obtained is compared with the empirical formula for the (n,(3)He) reaction cross-section.  相似文献   
94.
95.
96.
Intraoperative and postoperative free flap monitoring by means of oxygen tension measurement was carried out in 11 patients. We used an invasive flexible microcatheter that allowed for measurement of oxygen tension in all types of free flaps. Two cases of the measured flaps were buried free flaps which do not allow monitoring by clinical assessment. All flaps monitored in this study survived. One case of displacement of the microcatheter occurred. In one patient, the tissue pO2 monitor successfully detected early vascular thrombosis with subsequent reoperation and salvage of the free flap.  相似文献   
97.
This study was performed to evaluate the surgical strategy in patients with calvarial tumours, in order to design and modify a robot-assisted trepanation system. A total of 75 patients underwent craniectomy for the treatment of calvarial tumours during the 10-year period from 1993 to 2002. The patients' complaints, the size, location and histology of the tumour, and the various cranioplasty techniques used were analysed retrospectively. In a second procedure several craniectomies at typical locations according to the study's results were performed in a laboratory setting using a hexapod robotic tool, constructed at the Helmholtz-Institute, RWTH Aachen University, and plastic model heads. The workflow was documented and the reproducibility and the accuracy of the procedure were registered. A total of 83 surgical procedures were performed on 75 patients. The majority (87 %) of lesions treated surgically were located in the frontal, temporal and anterior parts of the parietal region. Histological examination revealed benign lesions in 66 % of the patients and dural involvement in 46 %. According to these results craniectomies were performed using the robotic system. Mean positioning accuracy of the robotic system while milling was 0.24 mm, with a standard deviation of 0.04 mm, and maximum error under 1 mm. Craniectomies leaving a 1-mm layer of the tabula interna intact to ensure a healthy dura were performed in several regions successfully. The majority of calvarial tumours, requiring surgical treatment in our patients, were located in cosmetically relevant areas in which drilling can be carried out with the robotic trepanation system. Consequently, the surgical approach had to be planned carefully in order to achieve a good cosmetic outcome.  相似文献   
98.
BG Aktuell     
This paper gives an overview of the changes in the sector of accident insurance companies over recent months and a prognosis for the changes that can still be expected, especially with reference to the election results.  相似文献   
99.
Consecutive patients (n = 215) who were referred to optometric (55%) or multidisciplinary (45%) low-vision services and above 50 years of age were recruited from four hospitals in the Netherlands. They completed two vision-related quality of life questionnaires, the Vision Quality of Life Core Measure (VCM1) and the Low Vision Quality of Life Questionnaire (LVQOL), before their first visit with low-vision services and 1 year later. At follow-up, patients referred to multidisciplinary low-vision services had lower scores on the mobility subscale of the LVQOL than patients referred to optometric low-vision services [5.3 points; 95% confidence interval (CI): 0.2-10.5]. Paired sample t-tests for the two groups of patients taken together show improvement for the VCM1 (3.1 points; 95% CI: 0.6-5.6) and deterioration for the basic aspects of vision (3.5 points; 95% CI: 1.1-5.9) and the mobility (6.6 points; 95% CI: 3.7-9.5) subscales of the LVQOL. In conclusion, people referred to optometric services showed less deterioration in mobility than those referred to multidisciplinary services. No differences were observed for any of the other subscales of the LVQOL and the VCM1. Future research in this field should include randomized controlled designs comparing low-vision services with no treatment or placebo.  相似文献   
100.
Cognitive function after on or off pump coronary artery bypass grafting.   总被引:1,自引:0,他引:1  
OBJECTIVE: To investigate cognitive outcome after on and off pump coronary artery bypass grafting. METHODS: Seventy patients between 50 and 80 years with stable angina pectoris, ejection fraction >30%, serum creatinine <150 micromol/l, and lack of tight main stem stenosis were randomized to on or off pump coronary artery bypass grafting. Standardized neuropsychological tests evaluated attention, verbal and visuo-spatial short-term and working memory, verbal learning, delayed recall, visuo-motor speed, and aspects of executive functions. Levels of anxiety and depression were also investigated. Testing was performed before and at 1 week, 1 and 6 months after surgery. RESULTS: There was no difference in cognitive impairment (defined as a 20% reduction in at least 20% of the tests) between groups. The incidence at 1 week post-operatively was 57% in the on pump group and 58% in the off pump group, after 1 month 30% and 12% and after 6 months 19% and 15%, respectively (p for interaction=0.19). There was no difference between groups in anxiety (p=0.18) or depression (p=0.48). CONCLUSIONS: This prospective, randomized study showed no differences in post-operative cognitive function after on pump compared to off pump coronary artery bypass grafting in low risk patients.  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