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   2132389篇
  免费   150805篇
  国内免费   3945篇
耳鼻咽喉   31480篇
儿科学   67844篇
妇产科学   60486篇
基础医学   300856篇
口腔科学   62882篇
临床医学   186669篇
内科学   406231篇
皮肤病学   48721篇
神经病学   167253篇
特种医学   84266篇
外国民族医学   595篇
外科学   326213篇
综合类   48490篇
现状与发展   7篇
一般理论   677篇
预防医学   152086篇
眼科学   51144篇
药学   165210篇
  8篇
中国医学   4926篇
肿瘤学   121095篇
  2018年   20762篇
  2016年   18592篇
  2015年   20744篇
  2014年   28827篇
  2013年   43180篇
  2012年   57661篇
  2011年   61106篇
  2010年   36115篇
  2009年   34433篇
  2008年   57546篇
  2007年   62343篇
  2006年   63158篇
  2005年   60591篇
  2004年   58579篇
  2003年   56288篇
  2002年   54938篇
  2001年   104363篇
  2000年   107052篇
  1999年   89719篇
  1998年   22776篇
  1997年   20286篇
  1996年   19741篇
  1995年   19748篇
  1994年   18347篇
  1993年   17257篇
  1992年   69411篇
  1991年   67119篇
  1990年   65950篇
  1989年   64000篇
  1988年   58998篇
  1987年   57885篇
  1986年   55185篇
  1985年   52315篇
  1984年   38865篇
  1983年   32961篇
  1982年   19219篇
  1981年   17314篇
  1979年   36608篇
  1978年   25711篇
  1977年   22525篇
  1976年   20260篇
  1975年   23002篇
  1974年   27183篇
  1973年   26527篇
  1972年   25257篇
  1971年   23647篇
  1970年   22148篇
  1969年   21315篇
  1968年   19666篇
  1967年   17610篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Clinical Oral Investigations - The aim of this in vitro study was to investigate the fatigue survival and fracture behavior of endodontically treated (ET) premolars restored with different types of...  相似文献   
73.

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   
74.
75.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Mit Beginn der Impfkampagne hat eine neue Phase der Bewältigung der Coronapandemie begonnen. Zulassung und Empfehlung...  相似文献   
76.
77.
Maternal and Child Health Journal - Background Prenatal substance use screening is recommended. The 4 P’s Plus screener includes questions on perceived problematic substance use in parents...  相似文献   
78.
Journal of Neuro-Oncology - MYC-driven medulloblastomas are highly aggressive childhood tumors with dismal outcomes and a lack of new treatment paradigms. We identified that targeting replication...  相似文献   
79.
KRAS oncogene mutations cause sustained signaling through the MAPK pathway. Concurrent inhibition of MEK, EGFR, and HER2 resulted in complete inhibition of tumor growth in KRAS-mutant (KRASm) and PIK3CA wild-type tumors, in vitro and in vivo. In this phase I study, patients with advanced KRASm and PIK3CA wild-type colorectal cancer (CRC), non-small cell lung cancer (NSCLC), and pancreatic cancer, were treated with combined lapatinib and trametinib to assess the recommended phase 2 regimen (RP2R). Patients received escalating doses of continuous or intermittent once daily (QD) orally administered lapatinib and trametinib, starting at 750 mg and 1 mg continuously, respectively. Thirty-four patients (16 CRC, 15 NSCLC, three pancreatic cancers) were enrolled across six dose levels and eight patients experienced dose-limiting toxicities, including grade 3 diarrhea (n = 2), rash (n = 2), nausea (n = 1), multiple grade 2 toxicities (n = 1), and aspartate aminotransferase elevation (n = 1), resulting in the inability to receive 75% of planned doses (n = 2) or treatment delay (n = 2). The RP2R with continuous dosing was 750 mg lapatinib QD plus 1 mg trametinib QD and with intermittent dosing 750 mg lapatinib QD and trametinib 1.5 mg QD 5 days on/2 days off. Regression of target lesions was seen in 6 of the 24 patients evaluable for response, with one confirmed partial response in NSCLC. Pharmacokinetic results were as expected. Lapatinib and trametinib could be combined in an intermittent dosing schedule in patients with manageable toxicity. Preliminary signs of anti-tumor activity in NSCLC have been observed and pharmacodynamic target engagement was demonstrated.  相似文献   
80.
BackgroundThe American Radium Society (ARS) Appropriate Use Criteria brain malignancies panel systematically reviewed (PRISMA [Preferred Reporting Items for Systematic Reviews and Meta-Analyses]) published literature on neurocognitive outcomes after stereotactic radiosurgery (SRS) for patients with multiple brain metastases (BM) to generate consensus guidelines.MethodsThe panel developed 4 key questions (KQs) to guide systematic review. From 11 614 original articles, 12 were selected. The panel developed model cases addressing KQs and potentially controversial scenarios not addressed in the systematic review (which might inform future ARS projects). Based upon quality of evidence, the panel confidentially voted on treatment options using a 9-point scale of appropriateness.ResultsThe panel agreed that SRS alone is usually appropriate for those with good performance status and 2–10 asymptomatic BM, and usually not appropriate for >20 BM. For 11–15 and 16–20 BM there was (between 2 case variants) agreement that SRS alone may be appropriate or disagreement on the appropriateness of SRS alone. There was no scenario (among 6 case variants) in which conventional whole-brain radiotherapy (WBRT) was considered usually appropriate by most panelists. There were several areas of disagreement, including: hippocampal sparing WBRT for 2–4 asymptomatic BM; WBRT for resected BM amenable to SRS; fractionated versus single-fraction SRS for resected BM, larger targets, and/or brainstem metastases; optimal treatment (WBRT, hippocampal sparing WBRT, SRS alone to all or select lesions) for patients with progressive extracranial disease, poor performance status, and no systemic options.ConclusionsFor patients with 2–10 BM, SRS alone is an appropriate treatment option for well-selected patients with good performance status. Future study is needed for those scenarios in which there was disagreement among panelists.  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