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   6738篇
  免费   569篇
  国内免费   28篇
耳鼻咽喉   133篇
儿科学   208篇
妇产科学   147篇
基础医学   575篇
口腔科学   241篇
临床医学   1132篇
内科学   965篇
皮肤病学   146篇
神经病学   482篇
特种医学   263篇
外国民族医学   1篇
外科学   1266篇
综合类   100篇
一般理论   6篇
预防医学   896篇
眼科学   95篇
药学   337篇
  1篇
中国医学   19篇
肿瘤学   322篇
  2023年   68篇
  2022年   55篇
  2021年   129篇
  2020年   148篇
  2019年   119篇
  2018年   193篇
  2017年   156篇
  2016年   184篇
  2015年   173篇
  2014年   312篇
  2013年   437篇
  2012年   394篇
  2011年   449篇
  2010年   306篇
  2009年   277篇
  2008年   313篇
  2007年   292篇
  2006年   337篇
  2005年   292篇
  2004年   270篇
  2003年   227篇
  2002年   227篇
  2001年   72篇
  2000年   52篇
  1999年   73篇
  1998年   71篇
  1997年   70篇
  1996年   84篇
  1995年   82篇
  1994年   91篇
  1993年   69篇
  1992年   61篇
  1991年   81篇
  1990年   49篇
  1989年   51篇
  1988年   51篇
  1987年   42篇
  1986年   39篇
  1985年   54篇
  1984年   59篇
  1983年   46篇
  1982年   36篇
  1981年   25篇
  1980年   26篇
  1979年   28篇
  1978年   43篇
  1977年   31篇
  1976年   32篇
  1970年   27篇
  1966年   28篇
排序方式: 共有7335条查询结果,搜索用时 15 毫秒
1.

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   
2.
3.
4.
Wound healing involves a number of cellular and molecular events, many of which are controlled by soluble growth factors. In the process of healing, hepatocyte growth factor, a cytokine known to act as mitogen, motogen, and morphogen, has been postulated to play multiple roles during several stages of this complex biological process. Produced primarily by stromal fibroblasts, hepatocyte growth factor regulates angiogenesis, vascular permeability, cell migration, matrix deposition and degradation, and other biological processes. The current article discusses recent progress in understanding the multiple roles played by this growth factor in tissue repair.  相似文献   
5.
To produce a stable epidermis, keratinocytes need to be firmly attached to the basement membrane. However, following wounding, keratinocytes are required to develop a migratory phenotype in order to reepithelialize the wound. To investigate some of the issues underlying reepithelialization, we have developed a three-dimensional in vitro model of tissue-engineered skin, comprising sterilized human dermis seeded with human keratinocytes and dermal fibroblasts. Using this model, we have shown that the inclusion of fibroblasts within the model increases the stability of keratinocyte attachment. We have also demonstrated that keratinocyte migration occurs most effectively in the absence of a basement membrane and following the inclusion of fibroblasts in the model. In addition, subjecting the keratinocyte layer to mechanical trauma induces a migratory phenotype. We conclude that this three-dimensional in vitro wound model can be used to increase our understanding of the factors that enhance keratinocyte migration and hence wound healing in vivo.  相似文献   
6.
Conclusions There is extensive evidence that perspectives on mental health consumer needs vary widely between consumers and other stakeholders-administrators, practitioners, and family members. Traditional methods of determining mental health consumer needs, based on professional input only, have inhibited program development. While progress has been achieved when shared goals have been identified, it has also been inhibited by a lack of known areas of consensus between stakeholder groups.Surveys provide a cost-effective step toward documenting shared views from stakeholders who have the greatest stake in influencing the size and direction of the mental health service system. Identifying shared views is necessary to coordinate stakeholder efforts. The most encouraging result of the surveys is that there are many areas of consensus and thus the potential exists for the stakeholders to coordinate their efforts toward shared goals to better meet important consumer needs by prioritizing services, improving practitioner training, and coordinating advocacy.  相似文献   
7.
1. Postmortem neurochemical investigations revealed interhemispheric asymmetry in the mediofrontal region of human brain. Significantly higher right hemisphere serotonin metabolite (5HIAA) content as well as increased maximal imipramine binding (IB) were found in the right hemisphere than in the left side.

2. IB did not show a gender difference in the mediofrontal area. However, women had higher IB in the right orbital frontal cortex than did men.

3. In vivo pharmaco-EEG results tend to support the postmortem neurochemical data. Intravenous chlorimipramine resulted in an asymmetric topographic distribution of the P300 auditory evoked potential, peak amplitudes were shifted to the right hemisphere.  相似文献   

8.
9.
10.
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