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   40821篇
  免费   3899篇
  国内免费   103篇
耳鼻咽喉   399篇
儿科学   1082篇
妇产科学   885篇
基础医学   5851篇
口腔科学   608篇
临床医学   4465篇
内科学   8156篇
皮肤病学   525篇
神经病学   3876篇
特种医学   1015篇
外国民族医学   4篇
外科学   5588篇
综合类   843篇
一般理论   51篇
预防医学   3934篇
眼科学   1102篇
药学   3566篇
中国医学   56篇
肿瘤学   2817篇
  2023年   226篇
  2022年   301篇
  2021年   829篇
  2020年   525篇
  2019年   835篇
  2018年   900篇
  2017年   652篇
  2016年   782篇
  2015年   889篇
  2014年   1260篇
  2013年   1784篇
  2012年   2568篇
  2011年   2701篇
  2010年   1518篇
  2009年   1361篇
  2008年   2315篇
  2007年   2441篇
  2006年   2475篇
  2005年   2452篇
  2004年   2376篇
  2003年   2101篇
  2002年   2001篇
  2001年   721篇
  2000年   619篇
  1999年   644篇
  1998年   501篇
  1997年   452篇
  1996年   423篇
  1995年   409篇
  1994年   341篇
  1993年   344篇
  1992年   544篇
  1991年   457篇
  1990年   404篇
  1989年   384篇
  1988年   429篇
  1987年   375篇
  1986年   337篇
  1985年   300篇
  1984年   342篇
  1983年   287篇
  1982年   266篇
  1981年   229篇
  1980年   200篇
  1979年   241篇
  1978年   179篇
  1977年   166篇
  1976年   183篇
  1975年   168篇
  1974年   174篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
15.
16.
17.
Tranexamic acid (TXA) is an antifibrinolytic drug that reduces surgical blood loss and death due to bleeding after trauma and post‐partum haemorrhage. One key issue for treatment success is early administration. While usually given intravenously, oral and intramuscular use would be useful in specific circumstances. Therefore, an understanding of TXA pharmacokinetics when given via different routes is valuable. The aim of this study was to perform an individual participant data meta‐analysis of pharmacokinetic studies with TXA given to healthy volunteers via different routes. We searched the following databases: PubMed, Web of Science, Wiley Online Library, Elsevier Science Direct and J‐STAGE. Individual subject data were extracted when available, otherwise arithmetic means were used. A population pharmacokinetic model was developed using nonlinear mixed effect modelling. Seven studies were included in the analysis with data from 10 patients for the IV route, six patients for the IM route and 114 patients for the oral route. The pharmacokinetics was ascribed to a two‐compartment model, and the main covariate was allometrically scaled bodyweight. Oral and IM bioavailabilities were 46 and 105%, respectively. For a 70 kg bodyweight, the population estimates were 7.6 L/h for clearance, 17.9 L for the volume of the central compartment, 2.5 L/h for the diffusional clearance and 16.6 L for the peripheral volume of distribution. Larger well‐designed studies are needed to describe the pharmacokinetics of TXA when given IM or as an oral solution before these can be recommended as alternatives to IV.  相似文献   
18.
BACKGROUND: Posterior spinal procedures through tubular exposures have been described. However, tubes restrain visibility and require co-axial instrument manipulation, increasing difficulty and potentially compromising surgical results. An independent-blade retractor system overcomes the obstacles of working through a tube and has been used to perform minimally-disruptive decompression and instrumented tranforaminal lumbar interbody fusion (TLIF). PURPOSE: To evaluate the advantages to patient recovery and surgical efficacy of this technique. METHODS/RESULTS: Retrospective review of technique employing a minimally-disruptive approach to decompression and transforaminal lumber interbody fusion (TLIF). CONCLUSIONS: Minimally-disruptive decompression and instrumented TLIF can be performed in a safe and effective manner using an independent-blade retractor system. Relative to traditional-open techniques, surgical goals can be accomplished, but with the benefits of minimally-disruptive surgery.  相似文献   
19.
BACKGROUND: Solid-organ transplantation has become the treatment of choice for patients with end-stage renal disease, end-stage liver failure, and some patients with type 1 diabetes mellitus. Similarly, surgical expertise and mechanical improvements have led to significant advances in laparoscopic surgery. Laparoscopic interventions are sometimes not pursued in transplant recipients due to the lack of strong supporting evidence for the use of laparoscopic techniques in these patients. METHODS: Using an extensive literature search, we review herein the available data on the utility of laparoscopic interventions in transplant recipients, with particular attention to the risks and benefits, indications, and contraindications for this complex patient population. RESULTS: Although randomized trials are few, multiple case reports indicate that many transplant recipients have benefited from laparoscopic interventions. CONCLUSION: The well-known benefits of laparoscopy could be extended to transplant recipients.  相似文献   
20.
Targeted silencing of disease-associated genes by synthetic short interfering RNA (siRNA) holds considerable promise as a novel therapeutic strategy. However, unmodified siRNA can be potent triggers of the innate immune response, particularly when associated with delivery vehicles that facilitate intracellular uptake. This represents a significant barrier to the therapeutic development of siRNA due to toxicity and off-target gene effects associated with this inflammatory response. Here we show that immune stimulation by synthetic siRNA can be completely abrogated by selective incorporation of 2'-O-methyl (2'OMe) uridine or guanosine nucleosides into one strand of the siRNA duplex. These noninflammatory siRNA, containing less than 20% modified nucleotides, can be readily generated without disrupting their gene-silencing activity. We show that, coupled with an effective systemic delivery vehicle, 2'OMe-modified siRNA targeting apolipoprotein B (apoB) can mediate potent silencing of its target mRNA, causing significant decreases in serum apoB and cholesterol. This is achieved at therapeutically viable siRNA doses without cytokine induction, toxicity, or off-target effects associated with the use of unmodified siRNA. This approach to siRNA design and delivery should prove widely applicable and represents an important step in advancing synthetic siRNA into a broad range of therapeutic areas.  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