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   1253918篇
  免费   96428篇
  国内免费   1560篇
耳鼻咽喉   16307篇
儿科学   40855篇
妇产科学   34943篇
基础医学   187782篇
口腔科学   34697篇
临床医学   117061篇
内科学   245253篇
皮肤病学   27259篇
神经病学   101082篇
特种医学   46759篇
外国民族医学   265篇
外科学   177990篇
综合类   25702篇
现状与发展   3篇
一般理论   569篇
预防医学   103798篇
眼科学   28005篇
药学   92223篇
  6篇
中国医学   1953篇
肿瘤学   69394篇
  2018年   13548篇
  2017年   10396篇
  2016年   11334篇
  2015年   13089篇
  2014年   18013篇
  2013年   27497篇
  2012年   37592篇
  2011年   39993篇
  2010年   23072篇
  2009年   22259篇
  2008年   37770篇
  2007年   40407篇
  2006年   39985篇
  2005年   39110篇
  2004年   37559篇
  2003年   35918篇
  2002年   34784篇
  2001年   55900篇
  2000年   56875篇
  1999年   47727篇
  1998年   12444篇
  1997年   11308篇
  1996年   11708篇
  1995年   11818篇
  1994年   11026篇
  1993年   10317篇
  1992年   38136篇
  1991年   37660篇
  1990年   36425篇
  1989年   35248篇
  1988年   32657篇
  1987年   32011篇
  1986年   30503篇
  1985年   28766篇
  1984年   21910篇
  1983年   19134篇
  1982年   11306篇
  1981年   10258篇
  1979年   20879篇
  1978年   15361篇
  1977年   12722篇
  1976年   11780篇
  1975年   12772篇
  1974年   15551篇
  1973年   15323篇
  1972年   14497篇
  1971年   13539篇
  1970年   12757篇
  1969年   12049篇
  1968年   11213篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.

Background

Salt and water accumulation leading to fluid overload is associated with increased mortality in intensive care unit (ICU) patients, but diuretics' effects on patient outcomes are uncertain. In this first version of the GODIF trial, we aimed to assess the effects of goal-directed fluid removal with furosemide versus placebo in adult ICU patients with fluid overload.

Methods

We conducted a multicentre, randomised, stratified, parallel-group, blinded, placebo-controlled trial in clinically stable, adult ICU patients with at least 5% fluid overload. Participants were randomised to furosemide versus placebo infusion aiming at achieving neutral cumulative fluid balance as soon as possible. The primary outcome was the number of days alive and out of the hospital at 90 days.

Results

The trial was terminated after the enrolment of 41 of 1000 participants because clinicians had difficulties using cumulative fluid balance as the only estimate of fluid status (32% of participants had their initially registered cumulative fluid balance adjusted and 29% experienced one or more protocol violations). The baseline cumulative fluid balance was 6956 ml in the furosemide group and 6036 ml in the placebo group; on day three, the cumulative fluid balances were 1927 ml and 5139 ml. The median number of days alive and out of hospital at day 90 was 50 days in the furosemide group versus 45 days in the placebo group (mean difference 1 day, 95% CI -19 to 21, p-value .94).

Conclusions

The use of cumulative fluid balance as the only estimate of fluid status appeared too difficult to use in clinical practice. We were unable to provide precise estimates for any outcomes as only 4.1% of the planned sample size was randomised.  相似文献   
54.
Cancer Causes & Control - Congenital malformations are strong risk factors for childhood cancer. Our objective was to determine whether cancer survival differs by birth defect status among...  相似文献   
55.
56.
Perinatal factors have been associated with soft tissue sarcomas (STS) in case-control studies. However, (i) the contributions of factors including fetal growth remain unknown, ( ii ) these factors have not been examined in cohort studies and (iii) few assessments have evaluated risk in specific STS subtypes. We sought to identify the role of perinatal and familial factors on the risk of STS in a large population-based birth cohort. We identified 4,023,436 individuals in the Swedish Birth Registry born during 1973–2012. Subjects were linked to the Swedish Cancer Registry, where incident STS cases were identified. We evaluated perinatal and familial factors obtained from Statistics Sweden, including fetal growth, gestational age, and presence of a congenital malformation. Poisson regression was used to estimate incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for associations between perinatal factors and STS overall, as well as by common subtypes. There were 673 individuals diagnosed with STS in 77.5 million person-years of follow-up. Having a congenital malformation was associated with STS (IRR = 1.70, 95% CI: 1.23–2.35). This association was stronger (IRR = 2.90, 95% CI: 1.25–6.71) in recent years (2000–2012). Low fetal growth was also associated with STS during the same time period (IRR = 1.86, 95% CI: 1.05–3.29). Being born preterm was associated with rhabdomyosarcoma (IRR = 1.74, 95% CI: 1.08–2.79). In our cohort study, those with congenital malformations and other adverse birth outcomes were more likely to develop a STS compared to their unaffected contemporaries. These associations may point to disrupted developmental pathways and genetic factors influencing the risk of STS.  相似文献   
57.
Gastric Cancer - Esophagogastric cancer (EGC) is one of the deadliest and costliest malignancies to treat. Care by high-volume providers can provide better outcomes for patients with EGC. Cost...  相似文献   
58.
59.
60.
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