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   1410436篇
  免费   113659篇
  国内免费   3332篇
耳鼻咽喉   18360篇
儿科学   46552篇
妇产科学   41044篇
基础医学   200729篇
口腔科学   37695篇
临床医学   125976篇
内科学   284391篇
皮肤病学   33354篇
神经病学   116854篇
特种医学   53828篇
外国民族医学   464篇
外科学   210485篇
综合类   32754篇
现状与发展   3篇
一般理论   487篇
预防医学   109984篇
眼科学   31490篇
药学   98495篇
  1篇
中国医学   3348篇
肿瘤学   81133篇
  2021年   10843篇
  2019年   11665篇
  2018年   16571篇
  2017年   12669篇
  2016年   14254篇
  2015年   16000篇
  2014年   22553篇
  2013年   33383篇
  2012年   45369篇
  2011年   47906篇
  2010年   28150篇
  2009年   27040篇
  2008年   44305篇
  2007年   46807篇
  2006年   47374篇
  2005年   45844篇
  2004年   43734篇
  2003年   41678篇
  2002年   40174篇
  2001年   72997篇
  2000年   74522篇
  1999年   61553篇
  1998年   16987篇
  1997年   15428篇
  1996年   15581篇
  1995年   14789篇
  1994年   13394篇
  1993年   12581篇
  1992年   45836篇
  1991年   43476篇
  1990年   41486篇
  1989年   39549篇
  1988年   36178篇
  1987年   35351篇
  1986年   32859篇
  1985年   31276篇
  1984年   23823篇
  1983年   20023篇
  1982年   12208篇
  1981年   10779篇
  1979年   20700篇
  1978年   14576篇
  1977年   12084篇
  1976年   11364篇
  1975年   11619篇
  1974年   13988篇
  1973年   13534篇
  1972年   12634篇
  1971年   11469篇
  1970年   10910篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
981.
There is limited information regarding oral health status and other predictors of oral health‐related quality of life. An association between oral health status and perceived oral health‐related quality of life (OHQOL) might help clinicians motivate patients to prevent oral diseases and improve the outcome of some dental public health programs. This study evaluated the relationship between older persons' OHQOL and their functional dentition, caries, periodontal status, chronic diseases, and some demographic characteristics. A group of 733 low‐income elders (mean age 72.7 ISD=4.71, 55.6% women, 55.1% members of ethnic minority groups in the U.S. and Canada) enrolled in the TEETH clinical trial were interviewed and examined as part of their fifth annual visit for the trial. OHQOL was measured by the Geriatric Oral Health Assessment Index (GOHAI); oral health and occlusal status by clinical exams and the Eichner Index; and demographics via interviews. Elders who completed the four‐year assessment had an average of 21.5 teeth (SD=6.9). with 8.5 occluding pairs (SD=4.6), and 32% with occlusal contacts in all four occluding zones. Stepwise multiple regressions were conducted to predict total GOHAI and its subscores (Physical, Social, and Worry). Functional dentition was a less significant predictor than ethnicity and being foreign‐bom. These variables, together with gender, years since immigrating, number of carious roots, and periodontal status, could predict 32% of the variance in total GOHAI, 24% in Physical, 27% in Social, and 21 % in the Worry subscales. These findings suggest that functional dentition and caries influence older adults' OHQOL, but that ethnicity and immigrant status play a larger role.  相似文献   
982.
BACKGROUND: Adjustable gastric banding is a popular bariatric operation in Europe. About 1500 patients per year undergo a such procedures in Germany. Clinical data on the rate of long-term complications such as pouch dilatation, slippage, and band migration are available in only a few long-term studies with small numbers of patients. Meta-analyses report on comordities and reduction in weight. The rate and management of long-term complications were examined at this inquiry. METHODS: Ninety hospitals were asked about rates of band implantation, follow-up, and complications. Thirty-eight hospitals (42.2%) participated in the study. The management of complications including slippage, pouch dilatation, and band migration was analyzed. RESULTS: At 35 hospitals, 4138 patients underwent gastric banding procedures in 25 hospitals over more than 5 years. The mean follow-up rate is presently 85.3%. Long-term complications were described in 8.6% of the patients. Pouch dilatation occurred in 5.0%, slippage in 2.6%, and band migration in 1.0%. CONCLUSIONS: Laparoscopic adjustable gastric banding can effectively achieve weight loss. However, band-related and functional complications influence late outcome. The rate of long-term complications was equivalent to that already in the literature.  相似文献   
983.
OBJECTIVE: To estimate the gestational age ranges that result in optimal birth outcomes for each of four risk-defined groups. STUDY DESIGN: Retrospective cohort study of singleton late third-trimester deliveries at a large urban teaching hospital between July 1995 and September 2003. Low-risk, advanced maternal age, hypertensive and diabetic patients were identified and grouped. Rates, by day of gestation at delivery, of cesarean delivery, major maternal perineal trauma, low 5-min APGAR score and NICU admission were determined for each study group. RESULTS: Each study group had meaningful changes in rates of obstetric outcomes as a function of gestational age at delivery and these patterns differed from group to group. A unique optimal time of delivery (OTD) was estimated for each group. The low-risk group OTD was calculated to be 37 weeks 1 day to 41 weeks 0 day; the advanced maternal age group OTD was 38 weeks 5 days to 39 weeks 6 days; the hypertension group OTD was 39 weeks 2 days to 40 weeks 1 day; and the diabetes mellitus group OTD was 40 weeks 3 days to 41 weeks 1 day. CONCLUSIONS: The OTD varied based on obstetrical risk. Strategies to increase the proportion of deliveries that occur within the OTD for specific risk-defined groups could theoretically improve birth outcomes.  相似文献   
984.
Introduction     
Raymond C. Read 《Hernia》2006,10(6):454-455
  相似文献   
985.
986.
The risks of viral transmission from trauma patients is a continuing concern to those involved in their care. However, the prevalence of hepatitis (HPT) in trauma patients is poorly described. The purpose of this study is to evaluate the prevalence of HPT in trauma patients admitted to an urban trauma center. Two hundred sixty-four consecutive admissions to an urban Level I trauma center underwent serologic screening for HPT. Risk factors were assessed by direct patient questioning. Serologic evidence of HPT B was found in 19.7 per cent of patients. Intravenous (IV) drug abusers represented eight per cent of the study population; this group had a 67 per cent rate of seropositivity. Hepatitis A was not found in any patient. Antigenemia was found in 1.9 per cent of patients. It is concluded that HPT B seropositivity is common in trauma patients. IV drug abusers have particularly high prevalence of HPT. This high prevalence rate of HPT B serology poses a significant risk to those involved with the care of trauma patients. The authors suggest that specific protocols to avoid the transmission of viral disease should be mandatory in urban trauma centers.  相似文献   
987.
New long-acting beta 2-adrenoceptor agonists, formoterol and salmeterol, may soon appear in several European countries for treatment of asthma. This review examines currently available information and compares the basic pharmacology and describes the clinical effects of these new drugs. The long duration of bronchodilation seen in clinical studies seems to be similar, whereas in isolated tissues there might be a difference in the binding characteristics to the beta 2-adrenoceptor. Long-acting beta 2-agonists could have an inhibitory effect on inflammatory events related to asthma, but the clinical relevance of these effects is not clear at present. Long-term studies up to one year with both new drugs have not shown any unexpected side-effects, and no tachyphylaxis to beta-adrenoceptor stimulation has been reported. Patients appear to strongly prefer the new drugs compared to the short-acting beta 2-agonists. The potential place for these drugs in the treatment of asthma is discussed and some pitfalls pointed out. It is likely that the long-acting beta 2-agonists will be beneficial to many asthmatic patients.  相似文献   
988.
989.
990.
ABSTRACT. Funclional behaviours in relation to age were investigated using data from approximately 3000 people on the Wessex Mental handicap Register. The main functional data on the register, the National Development Team's 24-item questionnaire, were cluster and factor analysed to derive a series of client-defining variables. Age-trends were analysed in relation to self and commiiniiy care skills (activities of daily living and instrumental activities of daily living), problem behaviours, chronic medical conditions, mobility and sensory abilities. Generally, it was found that differential mortality leads to an older population In gtwd health and with a high level of functional skills. As with ihe general population, however, people over 70 years old show increasing prevalence of age-related infirmities.  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