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   1762329篇
  免费   144673篇
  国内免费   3802篇
耳鼻咽喉   23786篇
儿科学   55995篇
妇产科学   51031篇
基础医学   249396篇
口腔科学   50391篇
临床医学   168610篇
内科学   343395篇
皮肤病学   38202篇
神经病学   141413篇
特种医学   72132篇
外国民族医学   474篇
外科学   263811篇
综合类   41583篇
现状与发展   8篇
一般理论   613篇
预防医学   132908篇
眼科学   40132篇
药学   133687篇
  3篇
中国医学   4508篇
肿瘤学   98726篇
  2021年   14844篇
  2018年   19765篇
  2017年   15850篇
  2016年   18046篇
  2015年   21622篇
  2014年   28403篇
  2013年   40698篇
  2012年   54591篇
  2011年   56763篇
  2010年   34037篇
  2009年   32201篇
  2008年   52065篇
  2007年   54061篇
  2006年   54109篇
  2005年   52307篇
  2004年   50886篇
  2003年   48090篇
  2002年   46409篇
  2001年   79442篇
  2000年   81648篇
  1999年   69281篇
  1998年   19389篇
  1997年   17818篇
  1996年   17674篇
  1995年   17232篇
  1994年   16059篇
  1993年   15044篇
  1992年   56772篇
  1991年   55115篇
  1990年   53721篇
  1989年   51893篇
  1988年   48140篇
  1987年   47410篇
  1986年   45089篇
  1985年   43575篇
  1984年   32561篇
  1983年   28062篇
  1982年   16531篇
  1981年   14833篇
  1979年   30880篇
  1978年   21413篇
  1977年   18112篇
  1976年   17004篇
  1975年   17829篇
  1974年   21763篇
  1973年   20923篇
  1972年   19151篇
  1971年   17932篇
  1970年   16462篇
  1969年   15415篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
OBJECTIVE: To evaluate the reproducibility of sonographic measurement of the lower uterine segment in pregnant women at term. METHODS: Two independent observers performed transabdominal sonography on 129 women between 36 and 38 weeks of gestation who had had a previous Cesarean section. Sonography was performed when the patients had a full and a half-full bladder; in 100 patients, the measurements were also performed transvaginally, with the patients having an empty bladder. Agreement was quantified by the intraclass correlation coefficient and, using a cut-off of 3.5 mm, by the kappa coefficient. RESULTS: The intraobserver agreement was generally high (intraclass correlation coefficient > 0.90). The interobserver agreement was higher on transvaginal (intraclass correlation coefficient, 0.94) compared with transabdominal (0.70 and 0.84, with full and half-full bladder, respectively) ultrasound. The kappa coefficient was 0.75 transvaginally, compared with 0.34 and 0.54 using the transabdominal approach, with full and half-full bladder, respectively. CONCLUSION: The agreement between two observers for sonographic transvaginal measurement of the lower uterine segment can be considered good, compared with poor to moderate agreement using the transabdominal approach.  相似文献   
83.
AIMS: To establish all-cause and cause-specific death rates, and risk factors for mortality in insulin-treated diabetic individuals living in the province of Canterbury, New Zealand. METHODS: Insulin-treated diabetic subjects (n = 995) on the Canterbury Diabetes Registry were followed up over 15 years and vital status determined. Death rates were standardized and hazard regression was used to model the effects of demographic covariates on relative survival time. RESULTS: There were 419 deaths in 11 226.3 person-years of follow-up with a standardized mortality ratio (SMR) of 2.0 (95% confidence interval (CI) 1.8-2.2). Relative mortality was greatest for the group aged 0-29 years (SMR 3.0 (95% CI 2.4-3.7)). After controlling for diabetes duration and gender, a 10-year increment in age of onset was associated with a 33% decrease in relative hazard (95% CI 29-36%), indicating that excess mortality due to diabetes declines with rising age of onset. After controlling for age of onset and gender, each 10-year increment in duration of diabetes is associated with a 26% decrease in relative hazard (95% CI 24-29%), indicating that with longer survival the mortality hazard approaches the general population hazard. Relative mortalities were increased for cardiovascular, renal and respiratory disease, but not malignancy. Relative mortality from acute metabolic complications was increased in the subgroup with age of onset of diabetes < 30 years and requiring insulin within 1 year of diagnosis. CONCLUSIONS: Mortality rates are high for insulin-treated diabetic individuals relative to the general population.  相似文献   
84.
Cidofovir is an acyclic nucleoside phosphonate with broad-spectrum activity against DNA viruses, including human papilloma virus (HPV). However, data on the efficacy of cidofovir in an immunosuppressive setting remain contradictory. We report for the first time on the promotion of the healing of recalcitrant warts in a patient with myelodysplastic syndrome with intravenous cidofovir treatment.  相似文献   
85.
The incidence of asthma has been reported to be associated with obesity. An alternative analysis, of net change in prevalence, does not require exclusion of those with asthma at baseline. Follow-up data were obtained from 9,552 participants in the European Community Respiratory Health Survey and the Swiss cohort Study on Air Pollution and Lung Disease in Adults. Incidence of asthma was analysed by proportional hazards regression, and net changes in symptoms and asthma status by generalised estimating equations, by obesity group. Incidence and net change in ever having had asthma were greater in females than in males, and in participants who remained obese compared with those who were never obese (hazard ratio 2.00, 95% confidence interval 1.25-3.20; excess net change 2.8%, 0.4-5.3% per 10 yrs). The effect of being obese on net change in diagnosed asthma was greater in females than in males, but for net change in wheeze without a cold it was greater in males. The present results are consistent with asthma being more frequently diagnosed in females, especially obese females. These findings may help to explain the reports of a stronger association between asthma and obesity in females than in males.  相似文献   
86.
87.
88.
89.
90.
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