全文获取类型
收费全文 | 1081篇 |
免费 | 66篇 |
国内免费 | 62篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 53篇 |
妇产科学 | 16篇 |
基础医学 | 91篇 |
口腔科学 | 15篇 |
临床医学 | 159篇 |
内科学 | 274篇 |
皮肤病学 | 19篇 |
神经病学 | 37篇 |
特种医学 | 231篇 |
外科学 | 80篇 |
综合类 | 28篇 |
预防医学 | 57篇 |
眼科学 | 8篇 |
药学 | 71篇 |
中国医学 | 3篇 |
肿瘤学 | 64篇 |
出版年
2021年 | 10篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 22篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 19篇 |
2014年 | 21篇 |
2013年 | 32篇 |
2012年 | 26篇 |
2011年 | 32篇 |
2010年 | 35篇 |
2009年 | 26篇 |
2008年 | 22篇 |
2007年 | 56篇 |
2006年 | 21篇 |
2005年 | 33篇 |
2004年 | 24篇 |
2003年 | 25篇 |
2002年 | 18篇 |
2001年 | 21篇 |
2000年 | 17篇 |
1999年 | 21篇 |
1998年 | 52篇 |
1997年 | 39篇 |
1996年 | 63篇 |
1995年 | 48篇 |
1994年 | 44篇 |
1993年 | 51篇 |
1992年 | 20篇 |
1991年 | 16篇 |
1990年 | 21篇 |
1989年 | 36篇 |
1988年 | 39篇 |
1987年 | 44篇 |
1986年 | 31篇 |
1985年 | 33篇 |
1984年 | 20篇 |
1983年 | 15篇 |
1982年 | 12篇 |
1981年 | 24篇 |
1980年 | 20篇 |
1979年 | 9篇 |
1978年 | 11篇 |
1977年 | 17篇 |
1976年 | 7篇 |
1975年 | 11篇 |
1972年 | 6篇 |
1971年 | 2篇 |
1969年 | 3篇 |
排序方式: 共有1209条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Short-Ti inversion-recovery pulse sequence: analysis and initial experience in cancer imaging 总被引:2,自引:0,他引:2
Inversion recovery (IR), commonly considered a pulse sequence capable of producing T1-weighted images with excellent display of normal anatomy, is versatile: The null point and peak time provide a useful, succinct summary of the properties of IR and its capacity for producing both T1- and T2-weighted images. Shortening of the inversion time (TI) and creation of a short-TI inversion-recovery (STIR) pulse sequence increases sensitivity to malignancy and other abnormalities by making the effects of prolonged T1 and T2 on signal intensity additive and by nulling the signal from fat. The authors examined over 300 patients with various malignancies and compared STIR images with T1- and T2-weighted images obtained at 0.5 T. In 43 cases, signal-difference-to-noise ratios (SD/Ns) were calculated between tumor, fat, and muscle. In general, STIR images demonstrated tumor as a conspicuously high-intensity area in a background of muted, discernible anatomic detail. The good contrast achieved with STIR sequences between tumor and fat (SD/N = 18.1) and tumor and muscle (SD/N = 12.9) consolidated into a single image the information contained separately on T1- and T2-weighted images, which facilitates efficient detection and localization of malignancy. 相似文献
6.
Sixteen cases of histopathologically proved solitary rectal ulcer syndrome were encountered. Fifteen patients underwent barium enema study; in nine cases the findings--including rectal stricture, granularity of the mucosa, and thickened rectal folds-were nonspecific. In six cases the study was normal. All patients had a long history of defecation disorders, and defecography was performed in all. In seven cases, intussusception of the rectal wall was seen; in another case the intussusception was accompanied by a rectocele. One case showed rectal prolapse. In four cases, failed relaxation of the puborectalis occurred and prevented the passage of the bolus; in another case there was abnormal perineal descent. In two patients studies were normal. In patients with defecation disorders, the possibility of this syndrome should be considered. Defecography is the method of choice for establishing the diagnosis. 相似文献
7.
J P de Boer G J Wolbink L G Thijs J W Baars J Wagstaff C E Hack 《Immunopharmacology》1992,24(2):135-148
Sepsis is a clinical syndrome that is usually induced by bacterial infections. It is generally assumed that the syndrome results from an excessive triggering of endogenous inflammatory mediators by the invading microorganisms. These mediators include substances released by activated monocytes, macrophages, endothelial cells and neutrophils such as cytokines, reactive oxygen species and proteases, as well as activation products of coagulation, fibrinolysis, contact and complement systems. Recent studies have suggested that cytokines and complement activation products may have overlapping biological activities. In addition, multiple interactions in vitro as well as in vivo between cytokines and complement have been described. Here we will review some of these recent studies and will discuss their relevance for the pathogenesis of sepsis and septic shock. 相似文献
8.
9.
10.