全文获取类型
收费全文 | 193670篇 |
免费 | 35850篇 |
国内免费 | 1409篇 |
专业分类
耳鼻咽喉 | 3454篇 |
儿科学 | 4964篇 |
妇产科学 | 3845篇 |
基础医学 | 16325篇 |
口腔科学 | 7099篇 |
临床医学 | 35570篇 |
内科学 | 44644篇 |
皮肤病学 | 4974篇 |
神经病学 | 22316篇 |
特种医学 | 7534篇 |
外国民族医学 | 6篇 |
外科学 | 31501篇 |
综合类 | 1343篇 |
现状与发展 | 40篇 |
一般理论 | 73篇 |
预防医学 | 20662篇 |
眼科学 | 3754篇 |
药学 | 7697篇 |
中国医学 | 116篇 |
肿瘤学 | 15012篇 |
出版年
2024年 | 788篇 |
2023年 | 5451篇 |
2022年 | 2107篇 |
2021年 | 4679篇 |
2020年 | 6463篇 |
2019年 | 3813篇 |
2018年 | 9014篇 |
2017年 | 8854篇 |
2016年 | 9745篇 |
2015年 | 10183篇 |
2014年 | 13288篇 |
2013年 | 15956篇 |
2012年 | 9938篇 |
2011年 | 9734篇 |
2010年 | 10390篇 |
2009年 | 12310篇 |
2008年 | 8987篇 |
2007年 | 8437篇 |
2006年 | 9150篇 |
2005年 | 7683篇 |
2004年 | 6720篇 |
2003年 | 5824篇 |
2002年 | 5723篇 |
2001年 | 3609篇 |
2000年 | 2868篇 |
1999年 | 3269篇 |
1998年 | 3212篇 |
1997年 | 2836篇 |
1996年 | 2699篇 |
1995年 | 2441篇 |
1994年 | 1743篇 |
1993年 | 1512篇 |
1992年 | 1871篇 |
1991年 | 1674篇 |
1990年 | 1496篇 |
1989年 | 1467篇 |
1988年 | 1341篇 |
1987年 | 1173篇 |
1986年 | 1167篇 |
1985年 | 1105篇 |
1984年 | 910篇 |
1983年 | 866篇 |
1982年 | 769篇 |
1981年 | 644篇 |
1980年 | 510篇 |
1979年 | 574篇 |
1978年 | 522篇 |
1977年 | 481篇 |
1974年 | 422篇 |
1973年 | 391篇 |
排序方式: 共有10000条查询结果,搜索用时 3 毫秒
101.
Workplace status and risk of hypertension among hourly and salaried aluminum manufacturing employees
Jane Ellen Clougherty Ellen A. Eisen Martin D. Slade Ichiro Kawachi Mark R. Cullen 《Social science & medicine (1982)》2009
An inverse relationship between workplace status and morbidity is well established; higher job status has been associated with reduced risks of heart disease, hypertension, and injury. Most research on job status, however, has focused on salaried populations, and it remains unclear whether job status operates similarly among hourly workers. Our objectives were to examine whether hourly status itself influences risk of hypertension after adjustment for socioeconomic confounders, and to explore the role of fine-scale job grade on hypertension incidence within hourly and salaried groups. We examined data for 14,999 aluminum manufacturing employees in 11 plants across the U.S., using logistic regression with adjustment for age, sex, race/ethnicity and other individual characteristics. Propensity score restriction was used to identify comparable groups of hourly and salaried employees, reducing confounding by sociodemographic characteristics. Job grade (coded 1 through 30, within hourly and salaried groups) was examined as a more refined measure of job status. Hourly status was associated with an increased risk of hypertension, after propensity restriction and adjustment for confounders. The observed effect of hourly status was stronger among women, although the propensity-restricted cohort was disproportionately male (96%). Among salaried workers, higher job grade was not consistently associated with decreased risk; among hourly employees, however, there was a significant trend, with higher job grades more protective against hypertension. Increasing the stringency of hypertension case criteria also increased the risk of severe or persistent hypertension for hourly employees. 相似文献
102.
103.
104.
Color Stability of Dry Earth Pigmented Maxillofacial Silicone A-2186 Subjected to Microwave Energy Exposure 总被引:2,自引:0,他引:2
Sudarat Kiat-amnuay DDS MS ; Dennis A. Johnston PhD ; John M. Powers PhD ; Rhonda F. Jacob DDS MS 《Journal of prosthodontics》2005,14(2):91-96
PURPOSE: The purpose of this study was to measure spectrophotometrically the color stability of pigmented A-2186 silicone maxillofacial elastomer with 10% by volume of titanium white dry earth opacifier before and after exposure to microwave energy over a simulated 1.5-year period of microwave sterilization. Materials AND METHODS: A-2186 silicone elastomer opacified with titanium white dry earth pigment, pigmented with 5 cosmetic dry earth pigment colors [no pigment (control) group (Pc), red (Pr), yellow ochre (Py), burnt sienna (Po), and a mixture of Pr + Py + Po color group (P3)], was used in this study. Each of the 5 experimental groups consisted of 5 specimens. All specimens were placed in a 250 ml glass beaker filled with 150 ml of water (replenished for each microwave exposure). An exposure of 6 minutes was used 18 times (simulating 1.5 years of microwave sterilization with one 6 minute exposure monthly). Reflectance values were measured by spectrophotometer. Three- and two-way analyses of variance with repeated measures were performed for the color difference (DeltaE*) with the factors of group/color/months, and group/months, respectively. Means were compared by Tukey Honest Significant Difference (HSD) multiple range test calculated at the 0.05 level of significance using SPSS. RESULTS: The trained human eye can detect color changes (DeltaE*) greater than 1.0. Most DeltaE* values of the red pigment group at all intervals and the mixed pigment group at 15- and 18- month intervals increased significantly greater than 1.0 (p < 0.001) compared with the control group. Yellow and burnt sienna groups remained the most color stable over time with DeltaE* values below 0.35. CONCLUSIONS: Lack of color stability of red dry earth pigmented A-2186 silicone maxillofacial elastomers was clinically significant after 12-month exposure to microwave energy as compared with yellow, burnt sienna, and opacified A-2186 dry earth pigments. 相似文献
105.
106.
107.
108.
Jean Marie Jully Marie Christine Béné Gérard Martin Gilbert Faure 《Journal of clinical periodontology》1986,13(3):223-227
The cellular infiltrate present in human diseased gingiva was analyzed in biopsies from 12 patients with gingivitis or periodontitis. The samples studied had been obtained in the course of surgery at inflammatory sites remaining after institution of periodontal treatment. Histological and immunological techniques were used to identify macrophages, B-cells, plasma-cells, T-cells and T cell subsets, as well as cells expressing class II HLA membrane antigens. T-cells appeared as the predominant population, but plasma-cells were also visualized in nearly all samples. Both OKT4+ and OKT8+ cells were seen in all cases, the latter being more numerous in periodontitis patients. Interdigitating-like cells were observed, positively labelled for class II antigens, as well as macrophages which were more numerous in periodontitis patients. These results suggest the participation of all components of the immune response in gingival disease, in a way resembling chronic recurrent inflammatory diseases. 相似文献
109.
110.
Priv.-Doz. Dr. Rüdiger Dissmann Joachim Schröder MD PhD Prof. Dr. med. Heinz Völler Prof. Dr. med. Steffen Behrens 《Clinical research in cardiology》2006,95(4):241-243
Summary During pacemaker implantation in a patient with permanent atrial fibrillation, it remained impossible to advance a passive
fixation lead with fins through the right atrium. However, a lead with a retractable screw easily passed the right atrium
and was positioned in the right ventricle. Transesophageal echocardiography revealed an extensive net–like perforated Eustachian
valve within the right atrium that had caused entrapment of the anchor fins during lead implantation. Remnants of embryonal
structures within the right atrium should be considered a rare possible barrier during pacemaker implantation. 相似文献