全文获取类型
收费全文 | 988篇 |
免费 | 55篇 |
国内免费 | 59篇 |
专业分类
儿科学 | 48篇 |
妇产科学 | 10篇 |
基础医学 | 79篇 |
口腔科学 | 16篇 |
临床医学 | 138篇 |
内科学 | 246篇 |
皮肤病学 | 27篇 |
神经病学 | 108篇 |
特种医学 | 231篇 |
外科学 | 36篇 |
综合类 | 28篇 |
一般理论 | 1篇 |
预防医学 | 60篇 |
眼科学 | 8篇 |
药学 | 36篇 |
中国医学 | 2篇 |
肿瘤学 | 28篇 |
出版年
2022年 | 2篇 |
2021年 | 12篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 16篇 |
2017年 | 13篇 |
2016年 | 10篇 |
2015年 | 24篇 |
2014年 | 19篇 |
2013年 | 32篇 |
2012年 | 23篇 |
2011年 | 23篇 |
2010年 | 31篇 |
2009年 | 27篇 |
2008年 | 29篇 |
2007年 | 60篇 |
2006年 | 21篇 |
2005年 | 28篇 |
2004年 | 27篇 |
2003年 | 20篇 |
2002年 | 19篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 20篇 |
1998年 | 53篇 |
1997年 | 40篇 |
1996年 | 60篇 |
1995年 | 49篇 |
1994年 | 41篇 |
1993年 | 49篇 |
1992年 | 9篇 |
1991年 | 12篇 |
1990年 | 19篇 |
1989年 | 27篇 |
1988年 | 33篇 |
1987年 | 34篇 |
1986年 | 25篇 |
1985年 | 30篇 |
1984年 | 16篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 22篇 |
1980年 | 19篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1977年 | 15篇 |
1976年 | 7篇 |
1975年 | 9篇 |
1970年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有1102条查询结果,搜索用时 501 毫秒
1.
L. van den Bemt M. P. de Vries L. van Knapen M. Jansen M. Goossens J. W. M. Muris C. P. van Schayck 《Clinical and experimental allergy》2006,36(2):233-237
BACKGROUND: Exposure to a high level of house dust mite allergens (HDMAs) is considered as a risk factor for HDM sensitization and development of asthma in genetically disposed people. Mattresses are one of the most important sources of HDMA in people's living environment. OBJECTIVE: The aim of this study was to evaluate the association between mattress characteristics and HDMA concentrations on mattresses. METHODS: Dust samples of mattress surfaces were taken to evaluate the level of Der p 1 allergen. All participants filled in a questionnaire about the type of mattress, the type of covering (upper layer) of the mattress, dwelling characteristics and cleaning habits. Humidity and temperature of the bedroom were measured at the time of dust sampling. RESULTS: One hundred and sixty-eight questionnaires were filled in. Synthetic upper layer of the mattress was associated with a higher level of Der p 1 compared with cotton upper layer (2.6 vs. 0.8 microg/g Der p 1). Moreover, higher relative humidity (RH) was associated with significant higher concentrations and density of Der p 1. CONCLUSIONS: Two factors were associated with lower levels of Der p 1 found on mattresses, namely: a cotton upper layer of the mattress compared with a layer of synthetic material and lower RH at the time of sampling. As far as we know, the association between type of upper layer and concentration of Der p 1 has not been described before and could lead to the formulation of practical advices in order to reduce HDMA concentrations on mattresses. 相似文献
2.
3.
4.
5.
6.
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
7.
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
8.
9.
In most textbooks of gastroenterology, diseases with their symptoms are discussed. The exact diagnostic value of these symptoms, however, regarding the differentiation between organic and functional disease, is not mentioned. A criteria-based meta-analysis of the few existing studies in this field was done. From the 14 identified studies, there were two that did not find any significant symptoms. In the other studies the diagnostic value of colonic symptoms showed great variability. Methodological deficiencies in these studies are probably responsible for the latter. The generalization of these results into general practice is not straightforward and needs research in general practice patients. 相似文献
10.