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   2074830篇
  免费   165567篇
  国内免费   4809篇
耳鼻咽喉   28928篇
儿科学   65846篇
妇产科学   60254篇
基础医学   296226篇
口腔科学   58143篇
临床医学   184981篇
内科学   406058篇
皮肤病学   46612篇
神经病学   171186篇
特种医学   80780篇
外国民族医学   626篇
外科学   314369篇
综合类   52496篇
现状与发展   4篇
一般理论   706篇
预防医学   163656篇
眼科学   48244篇
药学   149097篇
  1篇
中国医学   4463篇
肿瘤学   112530篇
  2018年   21956篇
  2017年   16867篇
  2016年   19078篇
  2015年   21662篇
  2014年   30782篇
  2013年   46347篇
  2012年   62676篇
  2011年   66160篇
  2010年   38812篇
  2009年   36989篇
  2008年   61569篇
  2007年   65690篇
  2006年   66135篇
  2005年   64288篇
  2004年   61930篇
  2003年   59371篇
  2002年   57333篇
  2001年   96985篇
  2000年   99263篇
  1999年   82963篇
  1998年   24142篇
  1997年   21867篇
  1996年   21794篇
  1995年   20699篇
  1994年   19132篇
  1993年   17926篇
  1992年   64894篇
  1991年   62445篇
  1990年   60389篇
  1989年   57728篇
  1988年   53555篇
  1987年   52414篇
  1986年   49365篇
  1985年   47362篇
  1984年   36391篇
  1983年   30855篇
  1982年   19226篇
  1981年   17364篇
  1979年   34120篇
  1978年   24295篇
  1977年   20298篇
  1976年   18939篇
  1975年   19883篇
  1974年   24391篇
  1973年   23495篇
  1972年   22215篇
  1971年   20379篇
  1970年   19432篇
  1969年   18390篇
  1968年   16970篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Esophageus or gaster resection in patients with malignant disease is still a treatment of choice. It is obvious that each surgical procedure in these patients carries some possibility of complications. Esophageo-gastric or esophageo-jejuno anastomosis has a 4-27% frequency of fistula occurrence. All these result in 65% mortality in cases of poorer prognosis. The aim of this paper is not to present all types of complications but to objectively analyse the usefulness of the covered stent placement in the treatment of anastomotic fistulas. We present six patients who were treated for postoperative fistula of esophageo-gastric anastomosis (1 case) or esophageo-jejuno anastomosis (5 cases). All patients were treated with stapler suture for digestive tract reconstruction after malignancy removal during the primary surgical procedure. Signs and symptoms of suture leak between 5-8 days post-surgery were observed. Conservative therapy was not effective. Thus a new method of treatment was employed - covered stent placement. The procedure was performed under X-ray control. In all treated patients there was change for the better and quick reduction of secretion from the fistulas was observed. All patients were discharged from the department after several days and all had survived at 30 days follow-up. Covered esophageal stent placement seems to be a safe and promising method of treatment for patients with anastomotic fistula which significantly reduces mortality and improves quality of live. Our experiences confirms that of other investigators.  相似文献   
992.
993.
994.
OBJECTIVE: This article 1) provides an overview of formal Health Sciences Teaching Scholars Programs as presented in medical education literature and 2) presents information about an innovative multidiscipline Teaching Scholars Program. METHOD: Health Sciences Teaching Scholars Programs and similar programs were reviewed in the medical education literature to identify similar and dissimilar characteristics. The WVU Teaching Scholars Program highlighted in this article is presented with a discussion of goals, objectives, target audiences, course length, session frequency, program topics, learning methods, and assessments of the programs. A summary of the WVU Teaching Scholars Program and two Teaching Scholars Programs at McGill University and the University of Toronto were presented at the Association for American Medical Colleges (AAMC) annual meeting in 2006 for input from the general medical education audience. RESULTS: Comparisons of Health Sciences Teaching Scholars Programs reveal that successful programs are uniquely shaped by their educational environments. Scholars report that they value learning new teaching methods and improving their educational careers. CONCLUSION: Teaching Scholars Programs are valuable for the development of enhancing both teaching and scholarship in Health Sciences Programs and must adapt to the uniqueness of their respective educational environments and must continue to nurture scholars beyond graduation.  相似文献   
995.
996.
OBJECTIVE: Cancer Care Ontario has recommended a population-based colorectal cancer (CRC) screening program using fecal occult blood testing. Patients who test positive should undergo further investigation, preferably colonoscopy. So far, no studies have been performed to quantify the costs or demands on the health care system at the community level. The number of consultations, colonoscopies and polypectomies, and the corresponding direct medical costs generated by the CRC screening program, between 2006 and 2015 in London, Ontario, were estimated using a decision analysis model in comparison with the population health model. METHODS: A faxed survey study was conducted to examine the current CRC screening practice among family physicians in London. Data from the survey and randomized studies were applied to a decision analysis model, which simulated the steps involved in population-based biennial and annual CRC screening between 2006 and 2015. The number of consultations, colonoscopies and polypectomies, and their associated costs were calculated. RESULTS: For a cohort population of 140,000, between 50 and 74 years of age, in 2006 to 2015, it is estimated that an average of 412 consultations, 463 colonoscopies and 174 polypectomies will be performed per 100,000 screen eligible population per year in biennial screening, and double in annual screening, reflecting an average of 8.7% or 17.6% increase annually in outpatient colonoscopies, respectively, compared with 2003. A mean of $285,000 or $562,000 per year would be required to support the extra consultation and endoscopic procedures generated by the biennial or annual screening. CONCLUSION: Population-based fecal occult blood testing screening for CRC appears to be a manageable strategy if a modest increase in endoscopic resources is allocated.  相似文献   
997.
This was a retrospective observational study of 11 consecutive patients of major primary postpartum haemorrhage (PPH) who had the B-Lynch suture at the time of caesarean section, performed between 1 March 2001 and 31 March 2004 at a teaching hospital in Scotland. Case-note review was performed in 123 patients, who had major primary PPH to identify patients who had B-Lynch sutures at the time of caesarean section. The patient's age, parity, gestation of pregnancy at which the B-Lynch suture was performed, the indication for caesarean section and the cause of primary major PPH were recorded. The operative details, intraoperative and immediate postoperative complications and the need for subsequent hysterectomy were noted. The patients were followed-up with clinic visits at 6 weeks and any further hospital referral for late postoperative complications and whether subsequent successful pregnancy was achieved, were documented. The incidence of major PPH in our centre was 0.5% of the total deliveries, of which 11 cases had the B-Lynch suture applied at the time of caesarean section. The patients were aged between 25 and 38 years old (mean 31 years). Parity ranged from 0 to 1 and the gestational age at which the procedure was performed ranged from 34 to 41 weeks (mean 38 weeks). Ten operations (91%) were performed by senior registrars supervised by the consultant on call and one (9%) case was performed by a consultant on call. All cases had the B-Lynch sutures performed for major primary PPH caused by uterine atony at the time of caesarean section. The weight of the babies delivered ranged between 2,110 - 4,820 g (mean 3,500 g). The total blood loss at surgery ranged from 2,000 - 10,000 ml (mean 3,500 ml). Only three patients (28%) required hysterectomy. All the patients made a good postoperative recovery. The hospital stay ranged from 4 - 24 days (mean 8 days). The patient who remained in hospital for 24 days did so because her baby was admitted into the neonatal unit. All the patients were reviewed 6 weeks postnatally. There was no significant morbidity. A subsequent successful pregnancy has been achieved in one patient.  相似文献   
998.
999.
A school microepidemic of tuberculosis.   总被引:1,自引:1,他引:0       下载免费PDF全文
C P Bredin  M Godfrey    J McKiernan 《Thorax》1991,46(12):922-923
BACKGROUND: Microepidemics of tuberculosis continue to occur in countries with a low incidence of tuberculosis. METHODS AND RESULTS: A microepidemic of tuberculosis in a secondary school with 604 girls in Cork city, Ireland, in 1986 with follow up to 1990 is described. Neonatal BCG vaccination was discontinued in the city in December 1972 so most of the 342 pupils who had received BCG were aged 14 years or more. Six active cases and 75 tuberculin positive cases were found. Four of the six girls with active disease had had neonatal BCG. The 75 pupils with a positive (grade 3 or 4) Heaf test response were given chemoprophylaxis with rifampicin and isoniazid for six months; none had developed active tuberculosis four years later. The brother of the girl who was the probable index case, however, developed active tuberculosis in 1988 despite similar chemoprophylaxis. CONCLUSION: The episode highlights the fact that children who have had neonatal BCG can develop active tuberculosis as teenagers.  相似文献   
1000.
Multiple intrahippocampal injections of gallamine impair performance of a representational memory task in rats. The binding of [3H]-(-)-quinuclidinyl benzilate (QNB) to rat brain sections was measured to determine if changes in receptor binding were associated with the deleterious effects of gallamine. [3H]-(-)-QNB binding to sections taken from gallamine-injected animals was compared with binding in saline-injected control animals. Autoradiographic analyses indicated an increase in [3H]-(-)-QNB binding sites within all layers of the cerebral cortex and in the superior colliculus in gallamine-treated animals as compared to saline-injected controls. Significant increases were noted in cortical layers IV and V (P less than 0.025) in gallamine-treated animals. No significant changes (P greater than 0.05) in the number of binding sites were observed in the hippocampus, neostriatum or various thalamic nuclei. The ability of unlabeled pirenzepine, gallamine and carbamylcholine to inhibit 0.2 nM [3H]-(-)-QNB binding also was measured to determine changes in the distribution of receptor subtypes. No significant changes were observed in any brain region for the binding of the selective antagonists pirenzepine and gallamine or the agonist carbamyl-choline. Although other possibilities are considered, the data suggest that an increase in the number of muscarinic receptors may contribute to the observed behavioral deficits associated with long-term gallamine treatment.  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