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   1351420篇
  免费   116679篇
  国内免费   7986篇
耳鼻咽喉   16879篇
儿科学   43199篇
妇产科学   36827篇
基础医学   185069篇
口腔科学   36773篇
临床医学   122589篇
内科学   279316篇
皮肤病学   32048篇
神经病学   110904篇
特种医学   56177篇
外国民族医学   284篇
外科学   212072篇
综合类   35642篇
现状与发展   4篇
一般理论   415篇
预防医学   107629篇
眼科学   28616篇
药学   95855篇
  35篇
中国医学   3682篇
肿瘤学   72070篇
  2018年   14079篇
  2017年   11278篇
  2016年   13380篇
  2015年   15238篇
  2014年   21041篇
  2013年   30826篇
  2012年   37826篇
  2011年   40521篇
  2010年   25543篇
  2009年   24908篇
  2008年   37582篇
  2007年   39872篇
  2006年   40989篇
  2005年   39512篇
  2004年   37507篇
  2003年   36655篇
  2002年   34560篇
  2001年   66582篇
  2000年   68332篇
  1999年   56926篇
  1998年   16936篇
  1997年   15152篇
  1996年   15370篇
  1995年   16272篇
  1994年   15162篇
  1993年   14139篇
  1992年   47113篇
  1991年   45795篇
  1990年   43995篇
  1989年   41811篇
  1988年   38756篇
  1987年   38090篇
  1986年   35850篇
  1985年   34640篇
  1984年   26331篇
  1983年   22065篇
  1982年   13809篇
  1981年   12405篇
  1980年   11665篇
  1979年   23506篇
  1978年   17020篇
  1977年   14336篇
  1976年   13139篇
  1975年   13694篇
  1974年   16067篇
  1973年   15379篇
  1972年   14167篇
  1971年   13023篇
  1970年   11863篇
  1969年   11092篇
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
101.
102.
103.
Medical education fellowship programs (MEFPs) are a form of faculty development contributing to an organization’s educational mission and participants’ career development. Building an MEFP requires a systematic design, implementation, and evaluation approach which aligns institutional and individual faculty goals. Implementing an MEFP requires a team of committed individuals who provide expertise, guidance, and mentoring. Qualified MEFP directors should utilize instructional methods that promote individual and institutional short and long term growth. Directors must balance the use of traditional design, implementation, and evaluation methodologies with advancing trends that may support or threaten the acceptability and sustainability of the program. Drawing on the expertise of 28 MEFP directors, we provide twelve tips as a guide to those implementing, sustaining, and/or growing a successful MEFP whose value is demonstrated by its impacts on participants, learners, patients, teaching faculty, institutions, the greater medical education community, and the population’s health.  相似文献   
104.
105.
目的探讨体外转染细胞周期素A2(Cyclin A2)基因对原代大鼠心肌细胞增殖的影响,为心脏再生提供细胞学依据。方法 SD乳鼠12只,分离、培养、鉴定原代乳鼠心肌细胞并分为3组,实验组:转染带有强化绿色荧光蛋白(GFP)和Cyclin A2基因的重组腺病毒(Ad-Cyclin A2-GFP);空病毒组:转染不含目的基因带有GFP的重组腺病毒(Ad-Null-GFP);阴性对照组:未做转染处理,仅加入等量的培养基。利用GFP示踪技术,评估原代心肌细胞转染效率;转染后的细胞继续体外培养3~5d,利用免疫荧光技术分别检测Cyclin A2、磷酸化组蛋白H3(H3P)、心肌肌钙蛋白-T(c Tn T)。结果 1.荧光GFP示踪表明原代心肌细胞的转染效率高达(97±0.74)%;2.免疫荧光标记显示,空病毒组和对照组结果相似;心肌细胞特异性标记蛋白c Tn T分布于细胞质,原代心肌细胞纯度高达(95±0.62)%;心肌细胞Cyclin A2主要在胞核内聚集,少数分布于细胞质。H3P为核蛋白在细胞核内分布。3.转染Cyclin A2后,实验组H3P阳性率明显高于空病毒组和对照组,差异具有统计学意义(P0.05);实验组可见大量多核细胞,以双核为主,伴少量3核细胞。结论腺病毒作为转染载体对原代心肌细胞有很好的侵染效率;Cyclin A2超表达促进原代心肌细胞形成双核。  相似文献   
106.
107.

Background

Limited data exists demonstrating the efficacy of minimally invasive surgery (MIS) compared to median sternotomy (MS) for multiple valvular disease (MVD). This systematic review and meta-analysis aims to compare operative and peri-operative outcomes of MIS vs MS in MVD.

Methods

PubMed, Ovid, and Embase were searched from inception until August 2019 for randomized and observational studies comparing MIS and MS in patients with MVD. Clinical outcomes of intra- and postoperative times, reoperation for bleeding and surgical site infection were evaluated.

Results

Five observational studies comparing 340 MIS vs 414 MS patients were eligible for qualitative and quantitative review. The quality of evidence assessed using the Newcastle-Ottawa scale was good for all included studies. Meta-analysis demonstrated increased cardiopulmonary bypass time for MIS patients (weighted mean difference [WMD], 0.487; 95% confidence interval [CI], 0.365-0.608; P < .0001). Similarly, aortic cross-clamp time was longer in patients undergoing MIS (WMD, 0.632; 95% CI, 0.509-0.755; P < .0001). No differences were found in operative mortality, reoperation for bleeding, surgical site infection, or hospital stay.

Conclusions

MIS for MVD have similar short-term outcomes compared to MS. This adds value to the use of minimally invasive methods for multivalvular surgery, despite conferring longer operative times. However, the paucity in literature and learning curve associated with MIS warrants further evidence, ideally randomized control trials, to support these findings.
  相似文献   
108.

Background

Arterial vascular anomalies in patients undergoing kidney transplantation (KT) are correlated with a higher incidence of early surgical complications, potentially causing graft loss. Arterial reconstruction allows patients to overcome these surgical challenges, thus minimizing the risk of poor outcomes. The aim of the present study is to retrospectively investigate the safety and effectiveness of the multiple arterial reconstruction technique with a Teflon patch in case of an unavailable aortic patch: to do so, surgical complications, graft function, and patient survival were evaluated.

Methods

During the period January 2009 to August 2016, 202 adult deceased-donor KTs were performed at our center. Group A (n = 27; reconstruction of multiple arteries) and Group B (n = 175; control group) were compared.

Results

No differences were observed between the 2 groups in terms of early postoperative course, with no vascular complication observed in Group A. No vascular patch infections were reported, nor longer cold ischemia time rates. Similarly, long-term survival rates were similar between the 2 groups.

Conclusions

The Teflon-patch arterial reconstruction technique appears to be safe and effective, with an acceptable balance of benefits and potential risks of using a prosthetic material. Studies based on larger series are needed to further validate this approach.  相似文献   
109.
Dermatophytid reactions are secondary eruptions in response to dermatophytosis. Only a few cases demonstrating an association between dermatophytid reactions and tinea capitis have been reported. Dermatophytid reactions were evaluated in patients diagnosed with kerion celsi. Patients admitted to the dermatology clinic of Van Regional Training and Research Hospital between November 22, 2012, and July 1, 2013, diagnosed with kerion celsi were evaluated for dermatophytid reactions. Six girls (32%) and 13 boys (68%) were included in this study. Dermatophytid reactions were detected in 13 of the 19 patients (68%). Seven patients (36.84%) had eczematous patches or plaques and three (15.8%) had papules. Eczematous lesions, papules, and pustules were noted in two patients (10.5%) and one (5.3%) had signs of an angioedema‐like reaction. Dermatophytid reactions in all patients were observed before the initiation of therapy. According to our clinical experiences, dermatophytid reactions in patients with kerion celsi were more common than reported. Eczematous scaly patches or plaques were the most frequently seen forms of dermatophytid in patients with kerion celsi. Dermatophytid reactions may occur before or after initiation of systemic antifungal therapy. Recognition of this reaction is important so that dermatophytids can be distinguished from drug reactions and the decision can be made whether to continue or to stop the systemic antifungal treatment.  相似文献   
110.
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