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   995730篇
  免费   76900篇
  国内免费   2608篇
耳鼻咽喉   12971篇
儿科学   34533篇
妇产科学   28624篇
基础医学   145276篇
口腔科学   27715篇
临床医学   90178篇
内科学   192970篇
皮肤病学   22936篇
神经病学   79260篇
特种医学   38510篇
外国民族医学   305篇
外科学   149556篇
综合类   23729篇
一般理论   388篇
预防医学   77727篇
眼科学   22566篇
药学   71997篇
  3篇
中国医学   2030篇
肿瘤学   53964篇
  2018年   10593篇
  2017年   8262篇
  2016年   9393篇
  2015年   10637篇
  2014年   14467篇
  2013年   22074篇
  2012年   29096篇
  2011年   30921篇
  2010年   18551篇
  2009年   17485篇
  2008年   28885篇
  2007年   30563篇
  2006年   31042篇
  2005年   29725篇
  2004年   29005篇
  2003年   27861篇
  2002年   26895篇
  2001年   47002篇
  2000年   48099篇
  1999年   40337篇
  1998年   11211篇
  1997年   10119篇
  1996年   10191篇
  1995年   9791篇
  1994年   9111篇
  1993年   8445篇
  1992年   32244篇
  1991年   31498篇
  1990年   31038篇
  1989年   29904篇
  1988年   27183篇
  1987年   27371篇
  1986年   25451篇
  1985年   24649篇
  1984年   18418篇
  1983年   15502篇
  1982年   9268篇
  1981年   8352篇
  1979年   16855篇
  1978年   12216篇
  1977年   10308篇
  1976年   9746篇
  1975年   10185篇
  1974年   12318篇
  1973年   11847篇
  1972年   10901篇
  1971年   10123篇
  1970年   9383篇
  1969年   8735篇
  1968年   8105篇
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
61.
62.
63.
Background: Breast cancer is a multifactorial disease that affects women worldwide. Its progression is likely to be executed by oxidative stress wherein elevated levels of reactive oxygen and nitrogen species drive several breast cancer pathologies. Spider venom contains various pharmacological peptides which exhibit selective activity to abnormal expression of ion channels on cancer cell surface which can confer potent anti-cancer activities against this disease. Methods: Venom was extracted from a Philippine tarantula by electrostimulation and fractionated by reverse phase-high performance liquid chromatography (RP-HPLC). Venom fractions were collected and used for in vitro analyses such as cellular toxicity, morphological assessment, and oxidative stress levels. Results: The fractionation of crude spider venom generated several peaks which were predominantly detected spectrophotometrically and colorimetrically as peptides. Treatment of MCF-7 cell line of selected spider venom peptides induced production of several endogenous radicals such as hydroxyl radicals (•OH), nitric oxide radicals (•NO), superoxide anion radicals (•O2−) and lipid peroxides via malondialdehyde (MDA) reaction, which is comparable with the scavenging effects afforded by 400 µg/mL vitamin E and L-cysteine (p<0.05). Concomitantly, the free radicals produced decrease the mitochondrial membrane potential and metabolic activity as detected by rhodamine 123 and tetrazolium dye respectively (p>0.05). This is manifested by cytotoxicity in MCF-7 cells as seen by increase in membrane blebbing, cellular detachment, caspase activity and nuclear fragmentation. Conclusion: These data suggest that the Philippine tarantula venom contains peptide constituents exhibiting pro-oxidative and nitrosative-dependent cytotoxic activities against MCF-7 cells and can indicate mechanistic insights to further explore its potential application as prooxidants in cancer therapy.  相似文献   
64.
65.
66.
67.

Background

Arterial vascular anomalies in patients undergoing kidney transplantation (KT) are correlated with a higher incidence of early surgical complications, potentially causing graft loss. Arterial reconstruction allows patients to overcome these surgical challenges, thus minimizing the risk of poor outcomes. The aim of the present study is to retrospectively investigate the safety and effectiveness of the multiple arterial reconstruction technique with a Teflon patch in case of an unavailable aortic patch: to do so, surgical complications, graft function, and patient survival were evaluated.

Methods

During the period January 2009 to August 2016, 202 adult deceased-donor KTs were performed at our center. Group A (n = 27; reconstruction of multiple arteries) and Group B (n = 175; control group) were compared.

Results

No differences were observed between the 2 groups in terms of early postoperative course, with no vascular complication observed in Group A. No vascular patch infections were reported, nor longer cold ischemia time rates. Similarly, long-term survival rates were similar between the 2 groups.

Conclusions

The Teflon-patch arterial reconstruction technique appears to be safe and effective, with an acceptable balance of benefits and potential risks of using a prosthetic material. Studies based on larger series are needed to further validate this approach.  相似文献   
68.
69.
70.
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