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   2663415篇
  免费   190905篇
  国内免费   5176篇
耳鼻咽喉   36609篇
儿科学   88376篇
妇产科学   74765篇
基础医学   380696篇
口腔科学   76957篇
临床医学   234812篇
内科学   517620篇
皮肤病学   58948篇
神经病学   207104篇
特种医学   101818篇
外国民族医学   597篇
外科学   406952篇
综合类   59876篇
现状与发展   5篇
一般理论   778篇
预防医学   197920篇
眼科学   63109篇
药学   197964篇
  8篇
中国医学   6124篇
肿瘤学   148458篇
  2018年   28303篇
  2017年   21419篇
  2016年   23812篇
  2015年   27176篇
  2014年   37766篇
  2013年   55999篇
  2012年   77325篇
  2011年   82107篇
  2010年   48579篇
  2009年   45575篇
  2008年   77329篇
  2007年   82904篇
  2006年   83772篇
  2005年   80983篇
  2004年   78167篇
  2003年   74867篇
  2002年   72778篇
  2001年   129859篇
  2000年   133210篇
  1999年   111330篇
  1998年   30445篇
  1997年   26834篇
  1996年   26993篇
  1995年   25722篇
  1994年   24006篇
  1993年   22100篇
  1992年   86876篇
  1991年   84475篇
  1990年   81993篇
  1989年   79311篇
  1988年   73000篇
  1987年   71470篇
  1986年   67778篇
  1985年   64564篇
  1984年   47695篇
  1983年   41019篇
  1982年   23695篇
  1981年   21137篇
  1979年   43688篇
  1978年   30333篇
  1977年   26061篇
  1976年   24351篇
  1975年   26281篇
  1974年   31544篇
  1973年   30324篇
  1972年   28556篇
  1971年   26410篇
  1970年   24642篇
  1969年   23432篇
  1968年   21985篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Delayed contrast enhancement after injection of a gadolinium-chelate (Gd-chelate) is a reference imaging method to detect myocardial tissue changes. Its localization within the thickness of the myocardial wall allows differentiating various pathological processes such as myocardial infarction (MI), inflammatory myocarditis, and cardiomyopathies. The aim of the study was first to characterize benign myocarditis using quantitative delayed-enhancement imaging and then to investigate whether the measure of the extracellular volume fraction (ECV) can be used to discriminate between MI and myocarditis.In 6 patients with acute benign myocarditis (32.2 ± 13.8 year-old, subepicardial late gadolinium enhancement [LGE]) and 18 patients with MI (52.3 ± 10.9 year-old, subendocardial/transmural LGE), myocardial T1 was determined using the Modified Look-Locker Imaging (MOLLI) sequence at 3 Tesla before and after Gd-chelate injection. T1 values were compared in LGE and normal regions of the myocardium. The myocardial T1 values were normalized to the T1 of blood, and the ECV was calculated from T1 values of myocardium and blood pre- and post-Gd injection.In both myocarditis and MI, the T1 was lower in LGE regions than in normal regions of the left ventricle. T1 of LGE areas was significantly higher in myocarditis than in MI (446.8 ± 45.8 vs 360.5 ± 66.9 ms, P = 0.003) and ECV was lower in myocarditis than in MI (34.5 ± 3.3 vs 53.8 ± 13.0 %, P = 0.004).Both inflammatory process and chronic fibrosis induce LGE (subepicardial in myocarditis and subendocardial in MI). The present study demonstrates that the determination of T1 and ECV is able to differentiate the 2 histological patterns.Further investigation will indicate whether the severity of ECV changes might help refine the predictive risk of LGE in myocarditis.  相似文献   
52.
53.
54.
55.
56.
57.
58.
There is a large and growing population of long-term cancer survivors. Primary care physicians (PCPs) are playing an increasingly greater role in the care of these patients across the continuum of cancer survivorship. In this role, PCPs are faced with the responsibility of managing a range of medical and psychosocial late effects of cancer treatment. In particular, the sexual side effects of treatment which are common and have significant impact on quality of life for the cancer survivor, often go unaddressed. This is an area of clinical care and research that has received increasing attention, highlighted by the presentation of this special issue on Cancer and Sexual Health. The aims of this review are 3-fold. First, we seek to overview common presentations of sexual dysfunction related to major cancer diagnoses in order to give the PCP a sense of the medical issues that the survivor may present with. Barriers to communication about sexual health issues between patient/PCPs in order are also described in order to emphasize the importance of PCPs initiating this important conversation. Next, we provide strategies and resources to help guide the PCP in the management of sexual dysfunction in cancer survivors. Finally, we discuss case examples of survivorship sexual health issues and highlight the role that a PCP can play in each of these case examples.  相似文献   
59.
The aim of the present study was to evaluate the antimicrobial activity of two synbiotic combinations, Lactobacillus fermentum with short-chain fructooligosaccharides (FOS-LF) and Bifidobacterium longum with isomaltooligosaccharides (IMO-BL), against enterohaemorrhagic Escherichia coli O157:H7 and enteropathogenic E. coli O86. Antimicrobial activity was determined (1) by co-culturing the synbiotics and pathogens in batch cultures, and (2) with the three-stage continuous culture system (gut model), inoculated with faecal slurry from an elderly donor. In the co-culture experiments, IMO-BL was significantly inhibitory to both E. coli strains, while FOS-LF was slightly inhibitory or not inhibitory. Factors other than acid production appeared to play a role in the inhibition. In the gut models, both synbiotics effectively inhibited E. coli O157 in the first vessel, but not in vessels 2 and 3. E. coli O86 was not significantly inhibited.  相似文献   
60.
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