全文获取类型
收费全文 | 2357169篇 |
免费 | 172097篇 |
国内免费 | 3420篇 |
专业分类
耳鼻咽喉 | 32112篇 |
儿科学 | 76067篇 |
妇产科学 | 63063篇 |
基础医学 | 348984篇 |
口腔科学 | 63801篇 |
临床医学 | 212268篇 |
内科学 | 458746篇 |
皮肤病学 | 51798篇 |
神经病学 | 185853篇 |
特种医学 | 88251篇 |
外国民族医学 | 489篇 |
外科学 | 354827篇 |
综合类 | 47730篇 |
现状与发展 | 12篇 |
一般理论 | 852篇 |
预防医学 | 183156篇 |
眼科学 | 54487篇 |
药学 | 175712篇 |
11篇 | |
中国医学 | 4655篇 |
肿瘤学 | 129812篇 |
出版年
2021年 | 19138篇 |
2019年 | 19695篇 |
2018年 | 27248篇 |
2017年 | 20513篇 |
2016年 | 22900篇 |
2015年 | 25853篇 |
2014年 | 36350篇 |
2013年 | 54304篇 |
2012年 | 75185篇 |
2011年 | 79974篇 |
2010年 | 47440篇 |
2009年 | 44880篇 |
2008年 | 75066篇 |
2007年 | 79933篇 |
2006年 | 80761篇 |
2005年 | 78193篇 |
2004年 | 74732篇 |
2003年 | 71992篇 |
2002年 | 69637篇 |
2001年 | 108952篇 |
2000年 | 111625篇 |
1999年 | 93651篇 |
1998年 | 27052篇 |
1997年 | 23717篇 |
1996年 | 24105篇 |
1995年 | 22754篇 |
1994年 | 20928篇 |
1993年 | 19745篇 |
1992年 | 72078篇 |
1991年 | 70157篇 |
1990年 | 68461篇 |
1989年 | 65710篇 |
1988年 | 60350篇 |
1987年 | 59179篇 |
1986年 | 55247篇 |
1985年 | 53040篇 |
1984年 | 39338篇 |
1983年 | 33417篇 |
1982年 | 19871篇 |
1979年 | 35887篇 |
1978年 | 25680篇 |
1977年 | 21246篇 |
1976年 | 20346篇 |
1975年 | 21830篇 |
1974年 | 26168篇 |
1973年 | 24815篇 |
1972年 | 23212篇 |
1971年 | 22046篇 |
1970年 | 20254篇 |
1969年 | 19324篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
952.
SETTING: Homes in Delhi, India. OBJECTIVE: To study the reach of mass media campaigns and their impact on awareness about tuberculosis (TB) control among homemakers/housewives. DESIGN: A community-based cross-sectional survey among homemakers residing in Delhi for more than 6 months. RESULTS: Of a total of 920 women interviewed, about 74.2% had seen specific TB-related health messages in one or more of the mass media. The maximum number of subjects could recall having seen billboards or television campaigns. The percentage of respondents who had correct information about various aspects of the disease was higher among those who had seen TB campaigns on any of the mass media. The effectiveness of radio and newsprint in communicating TB messages was found to be more limited than that of television and billboards. CONCLUSION: The mass media can be effective in getting messages about TB across to the community of women who are homemakers, especially in developing countries. In view of our findings, it may be recommended that television and billboards be used as tools for reaching out to them with specific campaigns regarding TB control, and that the use of these media should be strengthened further. 相似文献
953.
A Todo-Bom A Mota Pinto V Alves S Vale Pereira M Santos Rosa 《Journal of investigational allergology & clinical immunology》2007,17(2):107-112
BACKGROUND: Asthma is a chronic inflammatory disorder of the airways. The persistence of airway inflammation depends on a decrease in apoptosis of T lymphocytes and eosinophils and survival of these activated cells. T lymphocytes expressing gamma delta receptors can be identified in human lungs and play an important role in immune defence against pathogens and in the regulation of chronic inflammation. Aging is associated with evidence of some immune dysregulation. OBJECTIVE: The aim of this study was to analyze the apoptosis receptors of T lymphocytes in long-lasting asthma, to establish their correlation with activation markers such as CD25+ and human leukocyte antigen (HLA)-DR+, and to analyze the gama delta T cell expression in this disease. METHODS: A group of 64 individuals (group A) who had had asthma for more than 30 years (mean age [+/-SD] 72 +/- 5 years) and 61 healthy individuals acting as controls--group B with 41 individuals (mean age 79 +/- 7 years) and group C with 20 individuals (mean age 38 +/- 12 years) were included in the study. All subjects underwent clinical evaluation and spirometric testing. Peripheral blood cells were stained with monoclonal antibodies anti-CD3, anti-CD4, anti-CD8, anti-CD25, anti-TCR gamma delta, anti-HLA-DR and anti-CD95. Statistical comparisons were performed between the asthmatics and the elderly control group and between the elderly control group and the adult control group. RESULTS: The average percentage of predicted forced expiratory volume in the first second was 73.6 gamma delta 25.3. The mean values of T cell receptors for asthma group A vs elderly control group B vs adult control group C respectively, were the following: CD3, 74.9+/-7 vs. 74.8 +/- 8.8 (P=ns) vs. 76.7 +/- 4.2 (P=ns); CD4, 48.8 +/- 8.7 vs. 43.5 +/- 10.2 (P=ns) vs. 44.8 +/- 3.8 (P=ns); CD8, 23.3 +/- 7.9 vs. 25.7 +/- 10.2 (P=ns) vs. 25.6 +/- 4.5 (P=ns); CD25, 14.3 +/- 5.9 vs. 22.4 +/- 7.8 (P = .0001) vs. 5.5 +/- 2.4 (P = .0001); TCR gamma delta, 2.8 +/- 2.1 vs. 4.1 +/- 3.3 (P < .05) vs. 4.6 +/- 2.1 (P=ns); HLA-DR, 18.4 +/- 9.2 vs. 17.8 +/- 5.9 (P=ns) vs. 15.4 +/- 5.1 (P=ns) and CD95, 49.3 +/- 13.7 vs. 52.6 +/- 12.1 (P=ns) vs. 13.8 +/- 10.8 (P = .0001). CONCLUSIONS: The immunological and inflammatory changes related to ageing may cause an increase in CD95 and CD25 T cell expression. In asthma, blood cells may express increased activation and apoptosis markers but in elderly patients taking steroids, these receptors remain within normal ranges. The number of gamma delta T cells may be lower in long-lasting asthma, and have a limited modulatory effect on allergic inflammatory reactions. The evaluation of patients with long-lasting asthma should take into account the immunological and inflammatory changes present in the elderly in order to avoid results being misinterpreted. 相似文献
954.
C Martín-García J Carnés R Blanco J C Martínez-Alonso A Callejo-Melgosa A Frades T Colino 《Journal of investigational allergology & clinical immunology》2007,17(4):271-273
Many types of seafood require cooking before ingestion and it has been demonstrated that this cooking process may affect the antigenicity and allergenicity of the food. We describe a case of anaphylaxis caused by selective sensitization to razor shell, a mollusc. In vivo and in vitro studies confirmed sensitization to boiled razor shell. Analysis of the nature of the allergen yielded results that were consistent with the findings of other authors and suggested that allergens involved in seafood allergy are commonly high molecular weight proteins that, in most cases, are heat stable. 相似文献
955.
956.
Migraine is a prevalent disease that affects women more frequently than men. A particular trigger for migraine is the perimenstrual period. Acute migraine attacks during menstruation are treated similarly to nonmenstrual attacks, e.g., with analgesics or triptans. In women with pure menstrual migraine, short-term prophylaxis can be performed with nonsteroidal anti-inflammatory drugs (NSAIDs), estrogens, or low-dose triptans. During pregnancy migraine improves. After menopause frequency and severity of migraine attacks improve. 相似文献
957.
958.
959.
960.