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   63773篇
  免费   3396篇
  国内免费   223篇
耳鼻咽喉   1318篇
儿科学   3331篇
妇产科学   1710篇
基础医学   6921篇
口腔科学   3058篇
临床医学   5286篇
内科学   12208篇
皮肤病学   1684篇
神经病学   4890篇
特种医学   2253篇
外国民族医学   3篇
外科学   11236篇
综合类   904篇
现状与发展   1篇
一般理论   26篇
预防医学   3511篇
眼科学   1761篇
药学   4132篇
  4篇
中国医学   435篇
肿瘤学   2720篇
  2024年   57篇
  2023年   556篇
  2022年   574篇
  2021年   1366篇
  2020年   886篇
  2019年   1195篇
  2018年   1969篇
  2017年   1511篇
  2016年   1645篇
  2015年   1518篇
  2014年   1916篇
  2013年   3007篇
  2012年   4355篇
  2011年   5018篇
  2010年   2348篇
  2009年   1482篇
  2008年   3907篇
  2007年   4348篇
  2006年   4216篇
  2005年   4341篇
  2004年   4259篇
  2003年   4076篇
  2002年   3787篇
  2001年   1822篇
  2000年   1773篇
  1999年   1180篇
  1998年   485篇
  1997年   397篇
  1996年   354篇
  1995年   256篇
  1994年   209篇
  1993年   171篇
  1992年   221篇
  1991年   188篇
  1990年   173篇
  1989年   157篇
  1988年   128篇
  1987年   121篇
  1986年   124篇
  1985年   119篇
  1984年   102篇
  1983年   95篇
  1982年   97篇
  1981年   77篇
  1980年   69篇
  1979年   79篇
  1978年   69篇
  1977年   65篇
  1976年   61篇
  1974年   50篇
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
11.
12.
Clinical Oral Investigations - The aim of this study was the analysis of WNT10A variants in seven families of probands with various forms of tooth agenesis and self-reported family history of...  相似文献   
13.
Magnetic resonance elastography aims to non-invasively and remotely characterize the mechanical properties of living tissues. To quantitatively and regionally map the shear viscoelastic moduli in vivo, the technique must achieve proper mechanical excitation throughout the targeted tissues. Although it is straightforward, ante manibus, in close organs such as the liver or the breast, which practitioners clinically palpate already, it is somewhat fortunately highly challenging to trick the natural protective barriers of remote organs such as the brain. So far, mechanical waves have been induced in the latter by shaking the surrounding cranial bones. Here, the skull was circumvented by guiding pressure waves inside the subject's buccal cavity so mechanical waves could propagate from within through the brainstem up to the brain. Repeatable, reproducible and robust displacement fields were recorded in phantoms and in vivo by magnetic resonance elastography with guided pressure waves such that quantitative mechanical outcomes were extracted in the human brain.  相似文献   
14.
Purpose of the study: the aim of this study was to synthesize PFC fNIRS outcomes on the effects of cognitive tasks compared to resting/baseline tasks in healthy adults from studies utilizing a pre/post design.

Material and methods: original research studies were searched from seven databases (MEDLINE, EMBASE, CENTRAL, CINAHL, SCOPUS, PEDro and PubMed). Subsequently, two independent reviewers screened the titles and abstracts followed by full-text reviews to assess the studies' eligibility.

Results: eleven studies met the inclusion criteria and had data abstracted and quality assessed. Methodology varied considerably and yet cognitive tasks resulted in the ΔO2Hb increasing in 8 of the 11 and ΔHHb decreasing in 8 of 8 studies that reported this outcome. The cognitive tasks from 10 of the 11 studies were classified as “Working Memory” and “Verbal Fluency Tasks”.

Conclusions: although, the data comparison was challenging provided the heterogeneity in methodology, the results across studies were similar.  相似文献   

15.
Melatonin, the main hormone produced by the pineal gland, is secreted in a circadian manner (24‐hr period), and its oscillation influences several circadian biological rhythms, such as the regulation of clock genes expression (chronobiotic effect) and the modulation of several endocrine functions in peripheral tissues. Assuming that the circadian synchronization of clock genes can play a role in the regulation of energy metabolism and it is influenced by melatonin, our study was designed to assess possible alterations as a consequence of melatonin absence on the circadian expression of clock genes in the epididymal adipose tissue of male Wistar rats and the possible metabolic repercussions to this tissue. Our data show that pinealectomy indeed has impacts on molecular events: it abolishes the daily pattern of the expression of Clock, Per2, and Cry1 clock genes and Pparγ expression, significantly increases the amplitude of daily expression of Rev‐erbα, and affects the pattern of and impairs adipokine production, leading to a decrease in leptin levels. However, regarding some metabolic aspects of adipocyte functions, such as its ability to synthesize triacylglycerols from glucose along 24 hr, was not compromised by pinealectomy, although the daily profile of the lipogenic enzymes expression (ATP‐citrate lyase, malic enzyme, fatty acid synthase, and glucose‐6‐phosphate dehydrogenase) was abolished in pinealectomized animals.  相似文献   
16.
17.
18.
BackgroundWomen suffering from kidney disease are more prone to fertility problems, due to uremia. Fortunately, their fertility rate increases dramatically after renal transplantation. This study analyzes the predictors/risk factors of successful pregnancy with live birth outcome while presenting an overview of the 7-year experience of a single center.MethodsThis retrospective cohort study includes 239 women of reproductive age (18–40 years) who underwent renal transplantation in a tertiary Turkish clinic between October 1, 2011, and August 24, 2017. The subjects were invited to take part in a survey questioning their obstetric characteristics and they were assessed in 2 groups: fertile and infertile. Multivariable linear regression analysis was conducted to determine the predictors of a successful pregnancy.ResultsThirty-five 35 patients wished to become pregnant: 12 got pregnant spontaneously, while 21 failed to become pregnant (spontaneously). The mean age of the patients at the survey was 34 ± 7. Regular menstrual cycles after renal transplantation, tacrolimus-mycophenolate mofetil maintenance protocol, and age at transplantation were found to be predictors of spontaneous pregnancy. The duration of peritoneal dialysis was significantly longer in the infertile group (48 vs 12 months).ConclusionEnd-stage renal disease's negative impacts, including menstrual abnormality and fertility problems, can be overcome by successful kidney transplantation with appropriate immunosuppression. Minimizing the duration of peritoneal dialysis, particularly in patients who desire future fertility, may be accepted as a logical management strategy.  相似文献   
19.
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