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   2010791篇
  免费   164575篇
  国内免费   7698篇
耳鼻咽喉   27316篇
儿科学   62557篇
妇产科学   56459篇
基础医学   280624篇
口腔科学   57055篇
临床医学   179916篇
内科学   401990篇
皮肤病学   45466篇
神经病学   164908篇
特种医学   82023篇
外国民族医学   431篇
外科学   314788篇
综合类   51390篇
现状与发展   4篇
一般理论   653篇
预防医学   160747篇
眼科学   45193篇
药学   144018篇
  5篇
中国医学   3541篇
肿瘤学   103980篇
  2018年   19257篇
  2016年   17957篇
  2015年   20433篇
  2014年   28748篇
  2013年   43324篇
  2012年   54674篇
  2011年   58332篇
  2010年   35731篇
  2009年   34516篇
  2008年   54774篇
  2007年   58892篇
  2006年   59788篇
  2005年   58093篇
  2004年   56011篇
  2003年   54317篇
  2002年   51752篇
  2001年   90932篇
  2000年   93338篇
  1999年   78360篇
  1998年   23972篇
  1997年   21590篇
  1996年   22307篇
  1995年   21999篇
  1994年   20694篇
  1993年   19493篇
  1992年   65780篇
  1991年   64259篇
  1990年   62174篇
  1989年   59404篇
  1988年   55434篇
  1987年   54602篇
  1986年   51571篇
  1985年   49973篇
  1984年   38408篇
  1983年   32541篇
  1982年   20574篇
  1981年   18722篇
  1980年   17627篇
  1979年   36365篇
  1978年   26346篇
  1977年   22236篇
  1976年   20415篇
  1975年   21731篇
  1974年   26153篇
  1973年   25044篇
  1972年   23521篇
  1971年   21651篇
  1970年   20223篇
  1969年   19286篇
  1968年   17704篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
D M Eddy 《JAMA》1991,265(18):2399-401, 2405-6
Eddy argues for reform of the American health care system. In seeking health coverage, he explains, there are two positions: the first, that of society, seeks to allocate services efficiently; the second, that of the patient, seeks to optimize individual patients' care. Using his illustration of breast cancer coverage from a previous JAMA article (1991 Mar 20; 265 (11): 1446+), Eddy contends that a tradition of decision-making from the second position is the root of present health care inefficiencies. Eddy's ideal would be complete information to physicians and patients about service costs, benefits, and financial feasibility, and an agreed-upon standard of fair resource allocation, based on the threshold of a specific measure of benefit per resource. To approach this ideal, he concludes, we must recognize the problem, pursue education about service costs and benefits and people's desires of the system, and identify and review services that presently are inefficiently utilized.  相似文献   
993.
Thiazide diuretics may preserve bone mass and prevent elderly women's osteopenic fractures, but studies have not distinguished between thiazide preparations or examined former users. We performed a case-control study looking at thiazide use and subsequent hip fracture in postmenopausal female members of the Framingham Study cohort. Cases who had experienced a first hip fracture (n = 176) were compared with age-matched controls (n = 672). Results showed a modest protective effect of any recent thiazide use (not significant). However, recent pure thiazide users experienced significant protection against fracture (adjusted odds ratio, 0.31; 95% confidence interval, 0.11 to 0.88), whereas recent users of combination drugs containing thiazides experienced no protection (adjusted odds ratio, 1.16; 95% confidence interval, 0.44 to 3.05). Combination drugs generally contained only 25 mg of hydrochlorothiazide, suggesting that the small amount of thiazide was insufficient to preserve bone mass. Former thiazide users were not protected against fracture. In sum, recent pure thiazide use in women protects against hip fracture.  相似文献   
994.
In 1984, in addition to its standard traditional curriculum, Rush Medical College (Chicago, Ill) developed a Socratic problem-based method of teaching basic science material called the alternative curriculum. As part of an evaluation of this new curriculum, students in the two curricula were compared using three traditional measurements: (1) test scores from the National Board of Medical Examiners, Part I; (2) test scores from the National Board of Medical Examiners, Part II; and (3) performance on an oral examination. Alternative curriculum students did not differ significantly from their traditional curriculum classmates on National Board of Medical Examiners, Part I and Part II total scores, although their subset scores on Part I did tend to be lower, reaching significance in one subset area. Differences in performance favoring the traditional curriculum were primarily seen in the early years of the program. Alternative curriculum students in the class matriculated in 1987 scored significantly higher in three of five categories on the oral examination.  相似文献   
995.
996.
997.
The Cantekin affair   总被引:2,自引:2,他引:0  
D Rennie 《JAMA》1991,266(23):3333-3337
  相似文献   
998.
999.
1000.
OBJECTIVE: To assess the incidence and spectrum of complications associated with central venous catheter (CVC) placement in the critically ill infant. DESIGN: A prospective study of all babies hospitalized in a neonatal intensive care unit (NICU) from January 1989 to December 1989. Potential risk factors associated with infection were evaluated by a case-control comparison. SETTING: Conducted at a university-affiliated, tertiary care community hospital. PATIENTS: Neonates requiring intensive care and a central venous catheter. Controls consisted of noninfected babies. RESULTS: Of 263 critically ill neonates, only 13 (4.9%) required a CVC insertion. Seventeen CVCs were placed in these 13 neonates for a total duration of 600 days (median, 32 days/cannula). Fifteen (88%) of these cannulas had one or more complications during its catheter life including dislodgement or leakage (53%), occlusion or thrombosis (47%), infections (29%), or minor bleeding (12%). Five babies (29%) developed 6 episodes of bloodstream infection including 3 sporadic cases due to Staphylococcus epidermidis and a cluster of fungemia due to Malassezia furfur associated with lipid emulsion therapy. Infants with a CVC-associated infection were a younger gestational age (24 weeks versus 32 weeks, p = .04) and weighed less at birth (580 g versus 1285 g, p = .02). The overall rate of bloodstream infection was one episode per 100 days of catheter use. CONCLUSIONS: CVCs may be lifesaving to a critically ill neonate, but complications occur frequently. Use must be restricted to infants in whom alternate delivery routes of intravenous therapy or support are otherwise unavailable.  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