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   1682414篇
  免费   137107篇
  国内免费   2821篇
耳鼻咽喉   22673篇
儿科学   55020篇
妇产科学   48146篇
基础医学   237735篇
口腔科学   48911篇
临床医学   149034篇
内科学   332060篇
皮肤病学   34975篇
神经病学   137180篇
特种医学   67416篇
外国民族医学   477篇
外科学   256853篇
综合类   40877篇
现状与发展   4篇
一般理论   607篇
预防医学   129550篇
眼科学   38656篇
药学   126306篇
  3篇
中国医学   3079篇
肿瘤学   92780篇
  2018年   16287篇
  2016年   14109篇
  2015年   16483篇
  2014年   22775篇
  2013年   34929篇
  2012年   47416篇
  2011年   49820篇
  2010年   29255篇
  2009年   28023篇
  2008年   47922篇
  2007年   50735篇
  2006年   51298篇
  2005年   50099篇
  2004年   49319篇
  2003年   47121篇
  2002年   46215篇
  2001年   76310篇
  2000年   78760篇
  1999年   66974篇
  1998年   18742篇
  1997年   17240篇
  1996年   17083篇
  1995年   16781篇
  1994年   15759篇
  1993年   14800篇
  1992年   55891篇
  1991年   54200篇
  1990年   52918篇
  1989年   51211篇
  1988年   47570篇
  1987年   46912篇
  1986年   44647篇
  1985年   43249篇
  1984年   32625篇
  1983年   28190篇
  1982年   16954篇
  1981年   15182篇
  1980年   14262篇
  1979年   30847篇
  1978年   21514篇
  1977年   18241篇
  1976年   17114篇
  1975年   17934篇
  1974年   21778篇
  1973年   20970篇
  1972年   19065篇
  1971年   17929篇
  1970年   16458篇
  1969年   15368篇
  1968年   14050篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
Both vascular surgery and endovascular interventions traumatise the arterial wall, especially the endothelium. The vessel responds with neointimal hyperplasia and/or constrictive remodelling, and this is still the limiting factor in curative interventions. Stent placement prevents constrictive remodelling but is the main trigger for in-stent restenosis. Hyperproliferation of neointimal tissue is the main response to arterial thrombosis, local inflammation or medio-intimal injury such as occurs, for example, after balloon dilatation in the region of arterial anastomoses or of a thrombectomy (Fogarty-manoeuvre). At present, research on prevention of restenosis is focused on inhibiting neointimal hyperproliferation by using drug-eluting stents, and especially sirolimus- or paclitaxel-eluting stents. In addition, further experimental research work is in progress, with the aim of esablishing new treatment regimens and solving the problem of neointimal formation, thrombosis and constrictive remodelling. These include both local and systemic pharmacological therapy, brachy- and laser therapy, and many genetic treatment options, some of which are currently the subjects of experimental studies and early-stage clinical trials. Gene therapy seems like a promising way of preventing restenosis, but has not yet been tested in clinical trials. In the near future, selective, simultaneous, and perhaps even polyphasic regulation for gene silencing of two or more genes involved in the development of restenosis could improve the long-term patency rate.  相似文献   
74.
75.
76.
77.
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   
78.
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   
79.
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   
80.
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   
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