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   1347308篇
  免费   120787篇
  国内免费   2515篇
耳鼻咽喉   18435篇
儿科学   43178篇
妇产科学   36993篇
基础医学   191128篇
口腔科学   39403篇
临床医学   141295篇
内科学   268291篇
皮肤病学   30318篇
神经病学   112512篇
特种医学   49821篇
外国民族医学   265篇
外科学   193962篇
综合类   25844篇
现状与发展   42篇
一般理论   568篇
预防医学   116301篇
眼科学   29930篇
药学   93310篇
  7篇
中国医学   2027篇
肿瘤学   76980篇
  2021年   11673篇
  2019年   11657篇
  2018年   19612篇
  2017年   16929篇
  2016年   18315篇
  2015年   20148篇
  2014年   27270篇
  2013年   38106篇
  2012年   40585篇
  2011年   42812篇
  2010年   29002篇
  2009年   30250篇
  2008年   40617篇
  2007年   42263篇
  2006年   42890篇
  2005年   40761篇
  2004年   38662篇
  2003年   36802篇
  2002年   35651篇
  2001年   57625篇
  2000年   58033篇
  1999年   49554篇
  1998年   15224篇
  1997年   13890篇
  1996年   14357篇
  1995年   13399篇
  1994年   12022篇
  1992年   38837篇
  1991年   38215篇
  1990年   36871篇
  1989年   35686篇
  1988年   33112篇
  1987年   32354篇
  1986年   30808篇
  1985年   29023篇
  1984年   22153篇
  1983年   19433篇
  1982年   11558篇
  1979年   20994篇
  1978年   15494篇
  1977年   12892篇
  1976年   11920篇
  1975年   12860篇
  1974年   15652篇
  1973年   15402篇
  1972年   14569篇
  1971年   13585篇
  1970年   12833篇
  1969年   12077篇
  1968年   11229篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
Entering the postmodern world in which society is confronting crossroads, paradoxes, and complexity, the health care system is encountering a transformation more comprehensive and revolutionary than has ever been seen before. Analysis of the state of nursing vis a vis these transformations indicates that the current paradigm does not ensure the existence of the profession in the postmodern health care system. That is because of increased difficulties in consolidating the economic and quality issues into the core of nursing, and in understanding the complexity inherent in health related situations.  相似文献   
112.
113.
SUMMARY Current standard specifications for the laboratory evaluation of denture base materials require subjective assessment of colour stability. This study evaluates a new objective measurement technique for translucent denture base materials, by comparing quantitative data with the results obtained from a standard subjective method. Preliminary work on three representative commercial acrylic materials resulted in the selection of a white background for the quantification of colour change of these translucent materials. One half of each sample was exposed to artificial sunlight for 24 h.
The colour of both exposed and unexposed resin was measured on the CIE L*a*b* scale using a photoelectric colorimeter. Significant changes in the b* and E* values (P < 0.001) were observed following light exposure. Objective data for a wide range of commercial materials were compared with the results of a subjective evaluation and it was shown that a change in b* of 1.5 units was discernable subjectively by eye for 100% of the cases. It is suggested that this method and limit value could form the basis of a new objective colour change specification for polymeric dental materials.  相似文献   
114.
In order to satisfy the need to restore the aesthetics, phonetics and comfort and to facilitate optimal hygiene procedures, 20 edentulous patients were treated with a new concept of overdenture therapy on implants ad modum Brånemark. After 24±3.5 months the patients were re‐examined. They were asked to answer a questionnaire and use a Visual Analogue Scale (VAS) to give their opinion on the prosthetic treatment. The results indicate that an implant‐retained overdenture in the maxilla with this design can satisfy the patients needs in aesthetics, phonetics and comfort and can 1 facilitate oral hygiene measures.  相似文献   
115.
The results of the in vitro fertilisation programme at Tygerberg Hospital for the period April 1983 to January 1988 are presented. Of the 1117 laparoscopies performed, 825 patients reached the transfer stage. A live-birth rate of 9.3% was achieved. The pregnancy rate after transfer of 4 embryos was 25.9% compared with 15.4% after 2 embryos and 10.8% after 3 embryos (P = less than 0.0001). The multiple pregnancy rate was 2.8% in the group receiving 2 embryos and 11.7% and 10.4% in those receiving 3 and 4 embryos, respectively. Of the 77 successful pregnancies (90 babies), 1 baby died at 34 weeks' gestation as the result of abruptio placentae due to preeclampsia and 1 cot death occurred. The only congenital abnormality encountered was a cleft palate.  相似文献   
116.
Patients on long-term haemodialysis suffer from dialysis arthropathy due to the deposition of dialysis amyloid. We investigated the use of 99Tc-labelled methylene diphosphonate bone scans in 17 patients as a possible in vivo diagnostic technique. In most clinically affected joints, with the exception of shoulders and hands, there was increased radioisotope uptake consistent with uptake by periarticular bone. In addition, we describe intense soft-tissue uptake around some clinically affected large joints. In contrast, control groups of patients on haemodialysis without arthropathy and patients without renal failure did not have increased uptake. A semi-quantitative scale of uptake was devised, and the following correlations were significant: pain perception and isotope uptake score in the ankles and feet, and the number of radiological lesions and isotope uptake scores in the wrists and knees. The following sites where the radioisotope might bind in the affected joints are proposed: amyloid deposits, areas of soft-tissue calcification, or areas of increased bone turnover. It is concluded that whereas the scanning technique cannot make a definite diagnosis of amyloid and, therefore, cannot be expected to supersede histological diagnosis, it is a useful adjuvant investigation, of particular importance in those patients unable or unwilling to undergo biopsy.  相似文献   
117.
118.
119.
120.
The urological complications of 320 consecutive renal transplants performed at our institution between October 17, 1985 and November 10, 1989 are reviewed. The Leadbetter-Politano technique of ureteroneocystostomy was used in the first 160 patients (group 1) and an anterior extravesical technique modified from the methods of Witzel, Sampson and Lich was performed in the second 160 patients (group 2). Urological complications occurred in 15 patients (9.4%) in group 1 and 6 (3.7%) in group 2 (p = 0.04). Ureterovesical junction obstruction occurred in 6 patients (3.7%) in group 1 and 1 (0.6%) in group 2 (p = 0.05). Complications of leakage, ureteral necrosis and ureteral stricture were comparable in the 2 groups. Therefore, we advocate the use of the anterior extravesical technique over Leadbetter-Politano ureteral reimplantation based on the lower incidence of urological complications and various technical advantages, including less operative time, avoidance of a separate cystotomy, less hematuria and ability to use short donor ureters.  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