全文获取类型
收费全文 | 1004780篇 |
免费 | 69606篇 |
国内免费 | 2588篇 |
专业分类
耳鼻咽喉 | 13021篇 |
儿科学 | 34483篇 |
妇产科学 | 28460篇 |
基础医学 | 145411篇 |
口腔科学 | 27760篇 |
临床医学 | 90429篇 |
内科学 | 194028篇 |
皮肤病学 | 22931篇 |
神经病学 | 79334篇 |
特种医学 | 38420篇 |
外国民族医学 | 305篇 |
外科学 | 149594篇 |
综合类 | 23743篇 |
一般理论 | 386篇 |
预防医学 | 77899篇 |
眼科学 | 22647篇 |
药学 | 72000篇 |
19篇 | |
中国医学 | 2035篇 |
肿瘤学 | 54069篇 |
出版年
2018年 | 10590篇 |
2017年 | 8271篇 |
2016年 | 9420篇 |
2015年 | 10604篇 |
2014年 | 14435篇 |
2013年 | 22011篇 |
2012年 | 28996篇 |
2011年 | 30827篇 |
2010年 | 18493篇 |
2009年 | 17443篇 |
2008年 | 28790篇 |
2007年 | 30468篇 |
2006年 | 30966篇 |
2005年 | 29646篇 |
2004年 | 28925篇 |
2003年 | 27798篇 |
2002年 | 26816篇 |
2001年 | 46927篇 |
2000年 | 48038篇 |
1999年 | 40263篇 |
1998年 | 11179篇 |
1997年 | 10095篇 |
1996年 | 10162篇 |
1995年 | 9775篇 |
1994年 | 9090篇 |
1993年 | 8480篇 |
1992年 | 32249篇 |
1991年 | 31460篇 |
1990年 | 31007篇 |
1989年 | 29874篇 |
1988年 | 27168篇 |
1987年 | 27331篇 |
1986年 | 25435篇 |
1985年 | 24607篇 |
1984年 | 18397篇 |
1983年 | 15515篇 |
1982年 | 9290篇 |
1981年 | 8376篇 |
1979年 | 16860篇 |
1978年 | 12218篇 |
1977年 | 10314篇 |
1976年 | 9754篇 |
1975年 | 10180篇 |
1974年 | 12319篇 |
1973年 | 11844篇 |
1972年 | 10884篇 |
1971年 | 10115篇 |
1970年 | 9375篇 |
1969年 | 8725篇 |
1968年 | 8108篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
A. Sobke O. Makarewicz M. Baier C. Bär W. Pfister S.G. Gatermann M.W. Pletz C. Forstner 《International journal of antimicrobial agents》2018,51(2):213-220
The spread of antimicrobial resistance challenges the empirical treatment of urinary tract infections (UTIs). Among others, nitrofurantoin is recommended for first-line treatment, but acceptance among clinicians is limited due to chronic nitrofurantoin-induced lung toxicity and insufficient coverage of Enterobacteriaceae other than Escherichia coli. Nitroxoline appears to be an alternative to nitrofurantoin owing to its favourable safety profile, however data on its current in vitro susceptibility are sparse. In this study, susceptibility to nitroxoline was tested against 3012 urinary clinical isolates (including multidrug-resistant bacteria and Candida spp.) by disk diffusion test and/or broth microdilution. At least 91% of all Gram-negatives (n?=?2000), Gram-positives (n?=?403) and yeasts (n?=?132) had inhibition zone diameters for nitroxoline ≥18?mm. Except for Pseudomonas aeruginosa, nitroxoline MIC90 values were ≤16?mg/L and were 2- to >16-fold lower compared with nitrofurantoin. In extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae and methicillin-resistant Staphylococcus aureus (MRSA), MIC90 values of nitroxoline were two-fold higher compared with non-ESBL-producing enterobacteria and methicillin-susceptible S. aureus (MSSA). The in vitro efficacies of nitroxoline and nitrofurantoin against ATCC strains of E. coli, Enterococcus faecalis and Proteus mirabilis were compared by time–kill curves in Mueller–Hinton broth and artificial urine. Nitroxoline was non-inferior against E. coli, P. mirabilis and E. faecalis in artificial urine. In conclusion, nitroxoline showed a broad antimicrobial spectrum, with inhibition zone diameters and MICs of nitroxoline well below the EUCAST breakpoint for E. coli for most organisms, and thus may also be a target for therapy of uncomplicated UTIs. 相似文献
42.
43.
44.
45.
46.
Ester Teixidó-Compañó Albert Espelt Luis Sordo María J. Bravo Ana Sarasa-Renedo B. Iciar Indave Marina Bosque-Prous M. Teresa Brugal 《Gaceta sanitaria / S.E.S.P.A.S》2018,32(1):41-47
Objective
To determine differences between men and women in hazardous drinking, heavy cannabis use and hypnosedative use according to educational level and employment status in the economically active population in Spain.Method
Cross-sectional study with data from 2013 Spanish Household Survey on Alcohol and Drugs on individuals aged 25-64 [n = 14,113 (women = 6,171; men = 7,942)]. Dependent variables were hazardous drinking, heavy cannabis use and hypnosedative consumption; the main independent variables were educational level and employment situation. Associations between dependent and independent variables were calculated with Poisson regression models with robust variance. All analyses were stratified by sex.Results
Hazardous drinking and heavy cannabis use were higher in men, while women consumed more hypnosedatives. The lower the educational level, the greater the gender differences in the prevalence of this substances owing to different consumption patterns in men and women. While men with a lower educational level were higher hazardous drinkers [RII = 2.57 (95%CI: 1.75-3.78)] and heavy cannabis users [RII = 3.03 (95%CI: 1.88-4.89)] compared to higher educational level, in women the prevalence was the same. Women with a lower education level and men with a higher education level had higher hypnosedative consumption. Unemployment was associated with increased heavy cannabis use and hypnosedative use in both women and men and with lower hazardous drinking only in women.Conclusions
There are differences between men and women in the use of psychoactive substances that can be explained by the unequal distribution of substance use in them according to educational level. Unemployment was associated with substance use in both men and women. 相似文献47.
48.
49.
50.
Arjun K. Venkatesan Robert B. Reed Sungyun Lee Xiangyu Bi David Hanigan Yu Yang James F. Ranville Pierre Herckes Paul Westerhoff 《Bulletin of environmental contamination and toxicology》2018,100(1):120-126
Single particle inductively coupled plasma mass spectrometry (spICP-MS) was used to detect Ti-containing particles in heavily-used bathing areas of a river (Salt River) and five swimming pools. Ti-containing particle concentrations in swimming pools ranged from 2.8?×?103 to 4.4?×?103 particles/mL and were an order of magnitude lower than those detected in the Salt River. Measurements from the Salt River showed an 80% increase in Ti-containing particle concentration over baseline concentration during peak recreational activity (at 16:00 h) in the river. Cloud point extraction followed by transmission electron microscopy with energy dispersive X-ray analysis confirmed presence of aggregated TiO2 particles in river samples, showing morphological similarity to particles present in an over-the-counter sunscreen product. The maximum particle mass concentration detected in a sample from the Salt River (659 ng/L) is only slightly lower than the predicted no effect concentration for TiO2 to aquatic organisms (<?1 μg/L). 相似文献