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   3816204篇
  免费   326743篇
  国内免费   14135篇
耳鼻咽喉   52591篇
儿科学   120981篇
妇产科学   99599篇
基础医学   590179篇
口腔科学   106713篇
临床医学   351511篇
内科学   681873篇
皮肤病学   97982篇
神经病学   327243篇
特种医学   152324篇
外国民族医学   498篇
外科学   589708篇
综合类   114992篇
现状与发展   58篇
一般理论   2508篇
预防医学   321054篇
眼科学   88969篇
药学   265381篇
  23篇
中国医学   10264篇
肿瘤学   182631篇
  2021年   56430篇
  2020年   37443篇
  2019年   59019篇
  2018年   75153篇
  2017年   58385篇
  2016年   64350篇
  2015年   78182篇
  2014年   113426篇
  2013年   179188篇
  2012年   104474篇
  2011年   105839篇
  2010年   122392篇
  2009年   126889篇
  2008年   92866篇
  2007年   96585篇
  2006年   107211篇
  2005年   102099篇
  2004年   104200篇
  2003年   94466篇
  2002年   84049篇
  2001年   122021篇
  2000年   116020篇
  1999年   112770篇
  1998年   68167篇
  1997年   65431篇
  1996年   63364篇
  1995年   58795篇
  1994年   52782篇
  1993年   49277篇
  1992年   83451篇
  1991年   79872篇
  1990年   76433篇
  1989年   74998篇
  1988年   69766篇
  1987年   68452篇
  1986年   65251篇
  1985年   65123篇
  1984年   56843篇
  1983年   51507篇
  1982年   44939篇
  1981年   42070篇
  1980年   39650篇
  1979年   49175篇
  1978年   41116篇
  1977年   36914篇
  1976年   34212篇
  1975年   32988篇
  1974年   35725篇
  1973年   34380篇
  1972年   31848篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
13.
14.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
15.
Vestibular function laboratories utilize a multitude of diagnostic instruments to evaluate a dizzy patient. Caloric irrigators, oculomotor stimuli, and rotational chairs produce a stimulus whose accuracy is required for the patient response to be accurate. Careful attention to everything from cleanliness of equipment to threshold adjustments determine on a daily basis if patient data are going to be correct and useful. Instrumentation specifications that change with time such as speed and temperature must periodically be checked using calibrated instruments.  相似文献   
16.
17.
18.
19.

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   
20.
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