全文获取类型
收费全文 | 1900篇 |
免费 | 206篇 |
国内免费 | 36篇 |
专业分类
儿科学 | 74篇 |
妇产科学 | 31篇 |
基础医学 | 328篇 |
口腔科学 | 31篇 |
临床医学 | 204篇 |
内科学 | 340篇 |
皮肤病学 | 50篇 |
神经病学 | 178篇 |
特种医学 | 122篇 |
外科学 | 163篇 |
综合类 | 48篇 |
一般理论 | 1篇 |
预防医学 | 259篇 |
眼科学 | 10篇 |
药学 | 215篇 |
肿瘤学 | 88篇 |
出版年
2023年 | 10篇 |
2021年 | 24篇 |
2020年 | 20篇 |
2019年 | 31篇 |
2018年 | 33篇 |
2017年 | 34篇 |
2016年 | 31篇 |
2015年 | 42篇 |
2014年 | 61篇 |
2013年 | 67篇 |
2012年 | 75篇 |
2011年 | 68篇 |
2010年 | 62篇 |
2009年 | 67篇 |
2008年 | 60篇 |
2007年 | 100篇 |
2006年 | 69篇 |
2005年 | 65篇 |
2004年 | 66篇 |
2003年 | 62篇 |
2002年 | 53篇 |
2001年 | 42篇 |
2000年 | 50篇 |
1999年 | 54篇 |
1998年 | 50篇 |
1997年 | 47篇 |
1996年 | 45篇 |
1995年 | 38篇 |
1994年 | 52篇 |
1993年 | 38篇 |
1992年 | 35篇 |
1991年 | 38篇 |
1990年 | 35篇 |
1989年 | 50篇 |
1988年 | 47篇 |
1987年 | 33篇 |
1986年 | 34篇 |
1985年 | 29篇 |
1984年 | 28篇 |
1983年 | 26篇 |
1982年 | 24篇 |
1981年 | 26篇 |
1980年 | 24篇 |
1979年 | 14篇 |
1978年 | 14篇 |
1976年 | 23篇 |
1975年 | 17篇 |
1974年 | 13篇 |
1971年 | 9篇 |
1969年 | 12篇 |
排序方式: 共有2142条查询结果,搜索用时 15 毫秒
1.
R H Green C E Brightling S McKenna B Hargadon N Neale D Parker C Ruse I P Hall I D Pavord 《The European respiratory journal》2006,27(6):1144-1151
There is increasing evidence that the assessment of eosinophilic airway inflammation using induced sputum and measurement of airway hyperresponsiveness provides additional, clinically important information concerning asthma control. The aim of this study was to directly compare the effects of different treatments on these markers in patients with asthma and persistent symptoms, despite the use of low-dose inhaled corticosteroids. A double-blind four-way crossover study was performed, which compared a 1-month treatment with budesonide 400 mug b.i.d., additional formoterol, additional montelukast and placebo in 49 patients with uncontrolled asthma despite budesonide 100 mug b.i.d., with each treatment separated by a 4-week washout period. The change in sputum eosinophil count with formoterol (2.4 to 3.8% change, 0.6-fold reduction, 95% confidence interval (CI) 0.5-0.9) differed significantly from placebo (2.8 to 2.5% change, 1.1-fold reduction, 95% CI 0.7-1.6) and high-dose budesonide (2.7 to 1.6% change, 1.6-fold reduction, 95% CI 1.2-2.2). The effects of montelukast did not differ from placebo. The changes in methacholine airway responsiveness were small and did not differ between treatments. High-dose budesonide had the broadest range of beneficial effects on other outcomes, including symptom scores, morning peak expiratory flow and forced expiratory volume in one second. In conclusion, treatment given in addition to low-dose inhaled corticosteroids results in modest benefits. Formoterol and high-dose budesonide have contrasting effects on eosinophilic airway inflammation. 相似文献
2.
3.
4.
Relatedness of structures of a major immunogen in Trichomonas vaginalis isolates. 总被引:7,自引:3,他引:4 下载免费PDF全文
Solubilization of live Trichomonas vaginalis organisms with detergent caused the release of cysteine proteinases in the detergent extract which were inhibitable with N-alpha-p-tosyl-L-lysine chloromethyl ketone. The detergent extracts of all isolates tested possessed similar cysteine proteinase activities. These parasite proteinases rapidly degraded a prominent immunogen whose surface disposition undergoes phenotypic variation in some isolates. The relatedness of the forms of this immunogen among all isolates tested was confirmed by identical immunoblot patterns of autolysed immunogen, and data suggest the presence of repeating units or at least equidistant sites for proteinase cleavage within the immunogen molecule. 相似文献
5.
6.
This study attempts to replicate and extend the associations reported by Verbrugge among negative events, bad mood and symptoms. Employing the same symptomatology measure used in that study, but with more comprehensive event and mood questionnaires, we essentially replicated the same-day and lagged relationships reported by Verbrugge. One difference, however, was that undesirable events were a stronger predictor of symptom days than negative mood, whereas the opposite was true in Verbrugge's study. To further investigate the causal role of events and mood on symptoms, analyses were performed looking only at onset days of symptom episodes. This procedure greatly reduced same day event-symptom associations and eliminated event and mood's lagged relationships with symptoms. Our results do not, then, corroborate the triggering effect of events and mood for the onset of symptoms, although these variables may have a role in maintaining the duration of symptom episodes. 相似文献
7.
Age is a potential source of variation that contributes to differences between, but not within, twin pairs. In most genetic analyses of twin data, linear and other functions of age are usually removed prior to model fitting. This correction is typically applied only within twin groups of the same sex and zygosity, and no heterogeneity test of age regressions is performed. Here we include age as a variable in the model-fitting procedure and allow for tests of heterogeneity of age regressions across sex and zygosity groups. The LISREL formulation of the approach is illustrated with data collected from Australian twins on subjective impressions of drunkenness following alcohol consumption. The results indicate significant negative covariation of impressions of drunkenness with age. The data support a simple model of additive genetic and unique environmental variation. No evidence was found for sex differences in genetic or environmental components of variation.The theoretical work and data analysis described in this paper were made possible by NATO Grant 86/0823 and grants from the Belgian National Research Fund, the State University of Gent, and the Catholic University of Leuven. We are also grateful to Drs. R. Vlietinck and R. Derom for excellent organization of the successful workshop. Data collection was made possible by a grant from the Australian Associated Brewers to N.G.M. and Drs. J. G. Oakeshott, J. B. Gibson, and G. A. Starmer and by grants from the Australian National Health and Medical Research Council. The authors were supported by NIH Grants MH-40828 and AA-06781. 相似文献
8.
9.
We used arthrotomography to study the glenoid labrum in 114 patients. Sixty-nine of the patients had anatomic instability of the shoulder (including recurrent dislocation and subluxation of the shoulder), and 45 patients had functional instability of the shoulder (denoted by chronic pain, clicking of the joint, and the sensation that an unstable condition exists without the objective signs of it). Labral tears were revealed arthrotomographically in 86% of the patients with anatomic instability, while only 40% of the patients with functional instability had labral abnormalities, and these were primarily of minor severity. Fifty-six patients (44 of whom had anatomic instability; 12, functional instability) required surgery. The surgical findings were correlated with the arthrotomographic findings, and no false-positive results were revealed. However, arthrotomography demonstrated only part of the pathologic condition of two patients. These results confirm that there is a strong correlation between labral pathologic conditions and anatomic instability of the shoulder. Arthrotomographic studies have a great impact on the selection of therapy in cases of both anatomic and functional instability of the shoulder. 相似文献
10.
Hausegger KA; Cragg AH; Lammer J; Lafer M; Fluckiger F; Klein GE; Sternthal MH; Pilger E 《Radiology》1994,190(1):199