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   1654篇
  免费   128篇
  国内免费   19篇
耳鼻咽喉   12篇
儿科学   44篇
妇产科学   58篇
基础医学   292篇
口腔科学   29篇
临床医学   115篇
内科学   295篇
皮肤病学   50篇
神经病学   225篇
特种医学   37篇
外科学   157篇
综合类   20篇
一般理论   1篇
预防医学   195篇
眼科学   34篇
药学   98篇
中国医学   20篇
肿瘤学   119篇
  2023年   5篇
  2022年   14篇
  2021年   54篇
  2020年   41篇
  2019年   67篇
  2018年   66篇
  2017年   57篇
  2016年   47篇
  2015年   73篇
  2014年   92篇
  2013年   104篇
  2012年   148篇
  2011年   152篇
  2010年   73篇
  2009年   72篇
  2008年   123篇
  2007年   118篇
  2006年   106篇
  2005年   105篇
  2004年   89篇
  2003年   62篇
  2002年   60篇
  2001年   7篇
  2000年   4篇
  1999年   5篇
  1998年   6篇
  1997年   9篇
  1996年   2篇
  1995年   8篇
  1994年   5篇
  1993年   1篇
  1992年   2篇
  1991年   3篇
  1990年   1篇
  1989年   3篇
  1988年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1975年   2篇
  1974年   1篇
  1973年   3篇
  1968年   1篇
  1966年   4篇
  1905年   1篇
排序方式: 共有1801条查询结果,搜索用时 62 毫秒
1.
Beneficial therapeutic effects of phenolic acids have been proven in various research projects including in vivo and in vitro studies. Gentisic acid (GA) is a phenolic acid that has been associated with useful effects on human health, such as antiinflammatory, antigenotoxic, hepatoprotective, neuroprotective, antimicrobial, and especially antioxidant activities. It is an important metabolite of aspirin and also widely distributed in plants as a secondary plant product such as Gentiana spp., Citrus spp., Vitis vinifera, Pterocarpus santalinus, Helianthus tuberosus, Hibiscus rosa‐sinensis, Olea europaea, and Sesamum indicum and in fruits such as avocados, batoko plum, kiwi fruits, apple, bitter melon, black berries, pears, and some mushrooms. This study was undertaken to review the pharmacological effects, pharmacokinetic properties as well as toxicity and pharmaceutical applications of GA.  相似文献   
2.
3.
47,XYY syndrome is a sex chromosomal anomaly in men, which may be associated with infertility and has an incidence of 0.1% of male births. The clinical and paraclinical characteristics of men suffering from this anomaly have not been fully described. In this retrospective study, we present 37 cases of 47,XYY infertile men with sperm counts varying from normal to azoospermia, referred to the Genetics Laboratory at the Royan Institute, Iran. Thirteen individuals were mosaic and 24 non-mosaics. Non-mosaic patients were classified as azoospermic (nine cases) and normospermic/oligozoospermic men (15 cases). Two of the non-mosaic and three mosaic patients had secondary infertility. In addition, 13 of them underwent IUI, IVF or ICSI, and in seven cases, there was a biochemical pregnancy. The remaining 14 patients did not have ART. The 47,XYY syndrome is relatively unusual and can be missed clinically because of the lack of symptoms and of diverse phenotypes. Diagnosis of this aneuploidy can provide valuable data for counselling and early management of the patients who undergo fertility evaluation.  相似文献   
4.
The aim of this prospective study was to evaluate the relationship between morphometric parameters of metaphase II (MII) oocytes and the morphokinetic behaviour of subsequent embryos derived by intra-cytoplasmic sperm injection (ICSI). The association between oocyte morphometry: (whole oocyte), ooplasm, width of zona pellucida (ZP) and perivitelline space (PVS) and first polar body (PB) with embryo morphokinetic variables, including time of second PB extrusion (tPB2), pronuclei appearance (tPN), pronuclei fading (tPNf), formation of two to eight cells (t2 to t8) and irregular cleavage events [uneven at two cells stage, cell fusion (Fu) and trichomonas mitoses (TM)] were assessed. tPB2, t5 and t8 timings were related to the ooplasm diameter (p?=?0.003, r?=??0.12; p?=?0.001, r?=??0.16; p?r?=??0.36, respectively); otherwise, there were no significant relationships apart from an association between the oocyte morphometry and other morphokinetic parameters, irregular cleavage embryos as well as embryo arrest which approached significance (p?>?0.05). Overall, the data showed that morphometric parameters of oocytes did not provide a tool for the prediction of embryo morphokinetic or embryo selection in ICSI cycles. However, ooplasm diameter might be useful as a marker for predicting the timing of embryo cleavage.  相似文献   
5.
6.
7.
8.
9.

Objective

To understand the association between pre-operative depression symptoms, including cognitive and somatic symptom subtypes, and length of post-operative stay in patients undergoing coronary artery bypass graft (CABG) surgery, and the role of socioeconomic status (SES).

Methods

We measured depression symptoms using the Beck Depression Inventory (BDI) and household income in the month prior to surgery in 310 participants undergoing elective, first-time, CABG. Participants were followed-up post-operatively to assess the length of their hospital stay.

Results

We showed that greater pre-operative depression symptoms on the BDI were associated with a longer hospital stay (hazard ratio = 0.978, 95% CI 0.957–0.999, p = .043) even after controlling for covariates, with the effect being observed for cognitive symptoms of depression but not somatic symptoms. Lower SES augmented the negative effect of depression on length of stay.

Conclusions

Depression symptoms interact with socioeconomic position to affect recovery following cardiac surgery and further work is needed in order to understand the pathways of this association.  相似文献   
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