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   2784篇
  免费   159篇
  国内免费   21篇
耳鼻咽喉   20篇
儿科学   187篇
妇产科学   88篇
基础医学   297篇
口腔科学   37篇
临床医学   190篇
内科学   541篇
皮肤病学   91篇
神经病学   211篇
特种医学   166篇
外科学   391篇
综合类   125篇
预防医学   139篇
眼科学   88篇
药学   199篇
中国医学   19篇
肿瘤学   175篇
  2021年   45篇
  2020年   36篇
  2019年   51篇
  2018年   57篇
  2017年   27篇
  2016年   34篇
  2015年   40篇
  2014年   84篇
  2013年   97篇
  2012年   127篇
  2011年   138篇
  2010年   84篇
  2009年   75篇
  2008年   97篇
  2007年   114篇
  2006年   111篇
  2005年   102篇
  2004年   87篇
  2003年   95篇
  2002年   91篇
  2001年   77篇
  2000年   68篇
  1999年   75篇
  1998年   75篇
  1997年   46篇
  1996年   31篇
  1995年   22篇
  1994年   23篇
  1993年   23篇
  1992年   43篇
  1991年   53篇
  1990年   58篇
  1989年   44篇
  1988年   44篇
  1987年   38篇
  1986年   51篇
  1985年   49篇
  1984年   36篇
  1983年   37篇
  1982年   30篇
  1981年   21篇
  1980年   41篇
  1979年   40篇
  1978年   32篇
  1977年   35篇
  1976年   23篇
  1974年   39篇
  1973年   30篇
  1972年   20篇
  1970年   21篇
排序方式: 共有2964条查询结果,搜索用时 15 毫秒
61.
62.
Extended spectrum beta-lactamases (ESBLs) are plasmid mediated enzymes capable of hydrolyzing penicillins, broad spectrum-cephalosporins and monobactams. The ESBL producing K. pneumoniae strains are being reported from around the world including India. The present study was taken up to evaluate the ESBL production and in-vitro susceptibility of K. pneumoniae isolates from a hospital. The bacterial isolates collected during 2003 included 51 K. pneumoniae biochemically confirmed isolates from 395 patients admitted in various wards of a major hospital in New Delhi. The isolates were from pus, wound, pleural fluid, urine and tracheal aspirate of patients attending respiratory, urology and burns wards. Antimicrobial susceptibility was carried out by Kirby Bauer's disc diffusion technique using NCCLS criteria. A screening of ESBL production was done by Double-disc synergy test (DDST) and using E-test ESBL strips. The frequency of resistance among K. pneumoniae for the cephalosporins (cefoxitin, cefuroxime, cefotaxime, ceftazidime, and cefepime) and non-cephalosporins (aztreonam, piperacillin, chloramphenicol and trimethoprim-sulfamethoxazole) were in the range of 39.2-88.0% and 51.0-90.2% respectively. 14 different antimicrobial resistance profiles were recognized ranging from resistance to only four (n=6, 11.7%) to as many as ten (n=9, 17.7%). Among the 51 isolates of K. pneumoniae strains, a total of 36 (70.6%) could be identified as ESBL producers, that correlates with the high frequency of multi-drug resistant K. pneumoniae The study shows alarming rise in ESBL production among K. pneumoniae strains and high rate of resistance to a wide range of cephalosporin and non-cephalosporin group of antimicrobials.  相似文献   
63.
64.
The relation between the severity and duration of diabetes mellitus and the severity of ischemic heart disease is uncertain. The clinical findings and the findings at autopsy were studied in 185 patients with diabetes mellitus of adult onset who ranged in age from 37 to 91 years and had a clinical diagnosis of diabetes established for a few days to 50 years before death. No statistically significant association was demonstrated either by simple correlation or by multivariate regression analysis between the clinically diagnosed severity or duration of diabetes and either the overall coronary disease, the number of diseased vessels or the number of myocardial infarctions. The presence of other expected correlations in the multivariate analysis suggested that the results of this study were not spurious. However, comparison with 185 age- and sex-matched control patients revealed that on the average, diabetic patients have more overall coronary disease (p < 0.002), more diffuseness of coronary disease (p < 0.005), more coronary collateralizatlon (p < 0.001), more vessels involved by atherosclerosis (p < 0.001) and more myocardial infarcts (p < 0.001). The results suggest that although diabetes mellitus of adult onset is a condition in which the larger coronary arteries are subject to more atherosclerosis than are those in nondiabetic subjects, the progression of the atherosclerotic disease is unrelated to the duration or severity of the diabetes mellitus.  相似文献   
65.
Chest trauma. Approach and management.   总被引:3,自引:0,他引:3  
A synopsis of both blunt and penetrating thoracic trauma, this article outlines an approach to management for injuries to the lung, heart, esophagus, tracheobronchial tree, diaphragm, and major thoracic vessels. Also outlined are the management of rib fractures, scapula fractures, sternal fractures, and, in particular, flail chest with associated pulmonary contusion.  相似文献   
66.
67.
Valve replacement during pregnancy   总被引:1,自引:0,他引:1  
  相似文献   
68.
Nursing homes are becoming increasingly involved with medical education, and the Veterans Administration (VA) has been particularly active in this movement. We conducted a system-wide survey of VA nursing home facilities to determine the degree to which they participate in medical and other professional training and the features associated with such training. Of the 116 VA nursing homes in 1987, 113 (97.4%) returned completed questionnaires. Compared to "standard" VA facilities (n = 85), "teaching" nursing homes (n = 28)--those in which physicians received at least 20 hours of training per capita annually--were significantly larger, admitted and discharged significantly more patients per occupied bed, and placed a significantly larger proportion of discharged patients in noninstitutional community settings. Care costs in the teaching nursing homes were slightly but not significantly higher, despite significant increases in levels of professional staffing and amounts of training activities in all disciplines. During the survey year, teaching nursing homes provided training experiences for 440 students, residents, and fellows in internal and rehabilitation medicine, as well as for 2,700 other health professionals. The growth of teaching nursing homes in the VA system appears to be associated with positive changes in the pattern of health-care delivery, and it is increasing the number of health-care professionals trained in long-term care.  相似文献   
69.
OBJECTIVES: This study was designed to compare the three-year survival after percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG) in physician-directed and patient-choice registries with the Angina With Extremely Serious Operative Mortality Evaluation (AWESOME) randomized trial results. BACKGROUND: The AWESOME multicenter randomized trial and registry compared the long-term survival after PCI and CABG for the treatment of patients with medically refractory myocardial ischemia and at least one additional risk factor for adverse outcome with CABG. The randomized trial demonstrated comparable three-year survival. METHODS: Over a five-year period (1995 to 2000), 2,431 patients with medically refractory myocardial ischemia and at least one of five risk factors (prior heart surgery, myocardial infarction within seven days, left ventricular ejection fraction <0.35, age >70 years, intra-aortic balloon required to stabilize) were identified. By physician consensus, 1,650 patients formed a physician-directed registry assigned to CABG (692), PCI (651) or further medical therapy (307), and 781 were angiographically eligible for random allocation; 454 of these patients constitute the randomized trial, and the remaining 327 constitute a patient choice registry. Survival for CABG and PCI was compared using Kaplan-Meier curves and log-rank tests. RESULTS: The CABG and PCI 36-month survival rates for randomized patients were 79% and 80%, respectively. The CABG and PCI 36-month survival rates were both 76% for the physician-directed subgroup; comparable survival rates for the patient-choice subgroup were 80% and 89%, respectively. None of the global log-rank tests for survival demonstrated significant differences. CONCLUSIONS: Both registries support the randomized trial conclusion: PCI is an alternative to CABG for some medically refractory high-risk patients.  相似文献   
70.
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