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   37421篇
  免费   2141篇
  国内免费   202篇
耳鼻咽喉   442篇
儿科学   1175篇
妇产科学   1025篇
基础医学   3719篇
口腔科学   1218篇
临床医学   3276篇
内科学   8039篇
皮肤病学   678篇
神经病学   2226篇
特种医学   1352篇
外国民族医学   4篇
外科学   6820篇
综合类   856篇
现状与发展   3篇
一般理论   27篇
预防医学   2508篇
眼科学   1359篇
药学   2888篇
  1篇
中国医学   268篇
肿瘤学   1880篇
  2024年   39篇
  2023年   417篇
  2022年   1059篇
  2021年   1656篇
  2020年   989篇
  2019年   1264篇
  2018年   1572篇
  2017年   1144篇
  2016年   1240篇
  2015年   1334篇
  2014年   1689篇
  2013年   2066篇
  2012年   3115篇
  2011年   3015篇
  2010年   1709篇
  2009年   1475篇
  2008年   2262篇
  2007年   2325篇
  2006年   2047篇
  2005年   1814篇
  2004年   1644篇
  2003年   1356篇
  2002年   1191篇
  2001年   363篇
  2000年   307篇
  1999年   282篇
  1998年   197篇
  1997年   132篇
  1996年   141篇
  1995年   107篇
  1994年   95篇
  1993年   77篇
  1992年   147篇
  1991年   161篇
  1990年   128篇
  1989年   123篇
  1988年   104篇
  1987年   97篇
  1986年   88篇
  1985年   116篇
  1984年   77篇
  1983年   52篇
  1982年   53篇
  1981年   55篇
  1980年   41篇
  1979年   50篇
  1978年   40篇
  1975年   35篇
  1974年   36篇
  1973年   35篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.

Background

Lead acetate (Led) and mercury chloride (Mer) represent important ecological and public health concerns due to their hazardous toxicities. Naturally found products play a vital role in chemopreventive agent innovation. The current study aimed to assess the modifying effect of garlic (Gar) and/or vitamin E (Vit E) against the half-maximal inhibitory concentration (IC50) Led and/or Mer-induced cytotoxic, genotoxic and apoptotic effects.

Methods

Human lung cells (WI-38) were pretreated with Gar and/or Vit E for 24 h and then treated with Led and/or Mer either alone or with their combination for 24 h. Cytotoxicity of Led and Mer and the viability of Gar and Vit E were assessed using MTT assay. The alkaline comet assay was used to assess DNA damage, whereas QRT-PCR was performed to evaluate p53, Bax, and Bcl2 mRNA-expression.

Results

The results of this study showed that IC50 of Led was (732.72 μg/mL) and for Mer was (885.83 μg/mL), while cell viability effective dose for Gar was (300 μg/mL) and for Vit E was (26,800 μg/mL). Treating cells with the IC50-concentration of Led or Mer or their combination using half IC50 of both of them induced severe DNA-damage. Bax-expression was increased, while p53 and Bcl2-expressions were decreased. Pretreatment of cells with Gar and/or Vit E ameliorated the previous alternations.

Conclusions

Led and Mer can induce oxidative stress and change the expressions of apoptosis-related proteins in WI-38 cells. Gar and Vit E may be promising protective candidate agent against the toxic effect of heavy metals.  相似文献   
962.
Introduction: To-date, the only cure for symptomatic uterine fibroids (UFs) is surgical intervention. However, surgery may eliminate the hope of future pregnancies; moreover, the intrinsic risks of surgery make it a less favorable to women with UFs. Because of this, conservative medical therapies have become an attractive and prior option for those women. Leuprolide acetate (LA), a gonadotropin-releasing hormone (GnRH) agonist, is the only pharmacological agent currently approved for the short-term and pre-operative management of symptomatic UFs in the USA.

Areas covered: This systematic review covers the successes and failures of prominent drugs that have been researched for UFs in the past and agents that have shown promise in recent clinical trials. The most recent clinical trials and advances in drug therapy are presented in a comprehensive overview outlining the direction UF drug discovery is heading.

Expert opinion: Experts in the field are already on the forefront leading the responsibility to uncover potential drugs as long term fertility friendly viable options for non-invasive treatment/prevention of UFs. Indeed, a shift in the UF management is expected in the future.  相似文献   

963.
964.
Introduction: The true influence of the perioperative intravenous lidocaine on the development of postoperative cognitive deficit (POCD) in coronary artery bypass grafting (CABG) remains controversial. The principal aim is to undertake a meta-regression to determine whether moderator variables mediate the relationship between lidocaine and POCD.

Areas covered: We searched the Web of Science, PubMed database, Scopus and the Cochrane Library database (up to June 2017) and systematically reviewed a list of retrieved articles. Our final review includes only randomized controlled trials (RCTs) that compared infusion of lidocaine and placebo during cardiopulmonary bypass (CPB). Mantel–Haenszel risk ratio (MH RR) and corresponding 95% confidence interval (CI) was used to report the overall effect and meta-regression analysis. A total of 688 patients in five RCTs were included. POCD occurred in 34% of all cases. Perioperative lidocaine reduces POCD (MH RR 0.702 (95% CI: 0.541–0.909). Younger age, male gender, longer CPB and higher concentration of lidocaine significantly mediate the relationship between lidocaine and POCD in favour of the neuroprotective effect of lidocaine.

Expert commentary: The neuroprotective effect of lidocaine on POCD is consistent in spite of longer CPB time. A higher concentration of lidocaine strengthened the neuroprotective effect of lidocaine.  相似文献   

965.
Purpose: The aim of this study is to compare the effect of smoking in corneal endothelial cell number and morphology by specular microscopy on a non-smoker population.

Methods: Our cross-sectional study was performed on 150 participants from a non-smoker population. Non-contact specular microscopy (Tomey Corporation Inc., Nagoya, Japan) was performed in the center of the cornea of all subjects. The cell density (CD), average cell size (AVG), percent of hexagonality (HEX%) and central corneal thickness (CCT) were calculated and compared in both groups.

Results: Totally, 76 eyes of 76 smokers and 74 eyes of 74 non-smokers were enrolled in the study from 2015 to 2016. The mean age of smokers and non-smokers were 48.61?±?17.04 and 46.39?±?13.02, respectively. The mean number of pack/year among the smokers was 17.36?±?14.68. Also, the mean values of AVG and CD were significantly different for these two groups (p?=?0.011 and p?=?0.039, respectively). Other corneal endothelial variables did not show a significant difference between smokers and non-smokers (p?>?0.05). However, smokers with severe nicotine dependency had significantly greater AVG and lower CD in comparison with the non-smokers (p?=?0.004 and p?=?0.013, respectively).

Conclusion: Our study showed that smoking can cause significant changes in some of the corneal endothelial variables, but not all of them.  相似文献   
966.
Brain Imaging and Behavior - A higher incidence of cognitive impairment (CI) has previously been reported among orchiectomized testicular cancer patients (TCPs), but little is known about the...  相似文献   
967.
Karam  Mohamad  Ghanem  Ismat  Vergari  Claudio  Khalil  Nour  Saadé  Maria  Chaaya  Céline  Rteil  Ali  Ayoub  Elma  Saad  Eddy  Kharrat  Khalil  Skalli  Wafa  Assi  Ayman 《European spine journal》2022,31(9):2326-2338
European Spine Journal - To evaluate the global alignment of non-operated subjects with adolescent idiopathic scoliosis. A total of 254 subjects with AIS and 64 controls underwent low dose biplanar...  相似文献   
968.
969.
970.
The severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is rapidly infecting people worldwide, resulting in the infectious disease coronavirus disease 19 (COVID‐19) that has been declared a pandemic. Much remains unknown about COVID‐19, including its effects on solid organ transplant (SOT) recipients. Given their immunosuppressed state, SOT recipients are presumed to be at high risk of complications with viral infections such as SARS‐CoV‐2. Limited case reports in single SOT recipients, however, have not suggested a particularly severe course in this population. In this report, we present a dual‐organ (heart/kidney) transplant recipient who was found to have COVID‐19 and, despite the presence of a number of risk factors for poor outcomes, had a relatively mild clinical course.  相似文献   
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