全文获取类型
收费全文 | 937篇 |
免费 | 84篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 73篇 |
妇产科学 | 23篇 |
基础医学 | 150篇 |
口腔科学 | 27篇 |
临床医学 | 108篇 |
内科学 | 140篇 |
皮肤病学 | 7篇 |
神经病学 | 132篇 |
特种医学 | 27篇 |
外科学 | 63篇 |
预防医学 | 107篇 |
眼科学 | 10篇 |
药学 | 69篇 |
中国医学 | 1篇 |
肿瘤学 | 81篇 |
出版年
2024年 | 3篇 |
2023年 | 10篇 |
2022年 | 14篇 |
2021年 | 22篇 |
2020年 | 19篇 |
2019年 | 22篇 |
2018年 | 40篇 |
2017年 | 23篇 |
2016年 | 30篇 |
2015年 | 33篇 |
2014年 | 40篇 |
2013年 | 59篇 |
2012年 | 69篇 |
2011年 | 84篇 |
2010年 | 39篇 |
2009年 | 32篇 |
2008年 | 77篇 |
2007年 | 63篇 |
2006年 | 62篇 |
2005年 | 65篇 |
2004年 | 59篇 |
2003年 | 46篇 |
2002年 | 51篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 9篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1988年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
排序方式: 共有1021条查询结果,搜索用时 18 毫秒
1.
2.
3.
4.
Effects of x-ray scattering on full-field digital mammography are analyzed with the scattering model of Seibert and Boone [Med. Phys. 15, 567-575 (1988)]. A new method is introduced for the estimation of model parameters from measurements. It is shown that with breasts thinner than a certain threshold, removing the anti-scatter grid leads to an improved contrast-to-noise ratio with a smaller patient dose. A fast approximate algorithm is presented for determining the scattered field in a gridless digital mammogram. 相似文献
5.
Vascular endothelial growth factor C is required for sprouting of the first lymphatic vessels from embryonic veins 总被引:3,自引:0,他引:3
Karkkainen MJ Haiko P Sainio K Partanen J Taipale J Petrova TV Jeltsch M Jackson DG Talikka M Rauvala H Betsholtz C Alitalo K 《Nature immunology》2004,5(1):74-80
Lymphatic vessels are essential for immune surveillance, tissue fluid homeostasis and fat absorption. Defects in lymphatic vessel formation or function cause lymphedema. Here we show that the vascular endothelial growth factor C (VEGF-C) is required for the initial steps in lymphatic development. In Vegfc-/- mice, endothelial cells commit to the lymphatic lineage but do not sprout to form lymph vessels. Sprouting was rescued by VEGF-C and VEGF-D but not by VEGF, indicating VEGF receptor 3 specificity. The lack of lymphatic vessels resulted in prenatal death due to fluid accumulation in tissues, and Vegfc+/- mice developed cutaneous lymphatic hypoplasia and lymphedema. Our results indicate that VEGF-C is the paracrine factor essential for lymphangiogenesis, and show that both Vegfc alleles are required for normal lymphatic development. 相似文献
6.
Kirsi T. Ailus 《American journal of reproductive immunology (New York, N.Y. : 1989)》1994,31(4):189-196
PROBLEM: To obtain a systematic view of changes in the levels of immunoglobulins (Igs), other serum proteins, and autoantibodies during pregnancy and postpartum. METHOD: A series of 220 women were followed throughout pregnancy and four to six months postpartum. RESULTS: Immunoglobulin G (IgG) concentration clearly decreased toward term. The concentrations of IgM and IgA decreased only slightly. In most instances autoantibody levels paralleled changes in the corresponding immunoglobulin class levels. In few cases, however, there were clear deviations from this. With respect to IgG class autoantibodies, the highest autoantibody levels were found in the postpartum specimen. IgM class autoantbody levels remained almost constant throughout the follow-up period. CONCLUSIONS: The intrapregnancy decrease of IgG is mainly due to hemodilution, but when the effect of hemodilution is taken into account, total amounts of IgM and IgA are increased. The results suggests that compared to IgG the regulatory mechanisms of IgM and IgA are altered during pregnancy. 相似文献
7.
The relationship between job-related burnout and depressive disorders--results from the Finnish Health 2000 Study 总被引:7,自引:0,他引:7
Ahola K Honkonen T Isometsä E Kalimo R Nykyri E Aromaa A Lönnqvist J 《Journal of affective disorders》2005,88(1):55-62
BACKGROUND: Depression and burnout are common health problems in working populations today. They appear to be interrelated, and the need for their differential diagnosis has been highlighted in many reviews. We analysed the overlap of job-related burnout and depressive disorders, i.e., major depressive disorder, dysthymia, and minor depressive disorder. METHODS: We used the population-based 'Health 2000 Study' in Finland. Our nationally representative sample comprised 3276 employees aged 30-64 years. Burnout was assessed with the Maslach Burnout Inventory-General Survey. Diagnoses of depressive disorders were based on the Composite International Diagnostic Interview. RESULTS: Burnout and depressive disorders were clearly related. The risk of depressive disorders, especially major depressive disorder (12-month prevalence), was greater when burnout was severe. Half of the participants with severe burnout had some depressive disorder. Those with a current major depressive episode suffered from serious burnout more often than those who had suffered a major depressive episode earlier. LIMITATIONS: This study was cross-sectional. CONCLUSIONS: The concepts of burnout and depression complement each other and cover partly overlapping phenomena. Depressive disorders are related to job-related burnout, particularly when it is severe. A current major depressive episode is likely to be associated with the experience of burnout. When encountering working patients, it is recommended to assess both the occurrence of burnout and of depressive disorders. 相似文献
8.
Laurila E Syrjäkoski K Holli K Kallioniemi A Karhu R 《Cancer Genetics and Cytogenetics》2005,163(1):57-61
Mutations in the BRCA1 and BRCA2 genes are known to predispose to breast cancer. In Finland, however, only 21% of all breast cancer families have mutations in these genes. Recent studies have shown that large genomic alterations of BRCA1 are common in many countries. Because such alterations will be missed in conventional mutation screening strategies, we decided to screen Finnish breast and ovarian cancer families for genomic alterations by using a multiplex polymerase chain reaction method. The most characteristic features of BRCA1-related breast cancer were used to select patients, namely (1) both breast and ovarian cancer in the family (48 patients), (2) four or more breast cancers in family (22 patients), or (3) young age (< or =40 years) of onset (58 patients). A total of 128 patients were included in the study. All exons of BRCA1 were analyzed but no alterations were found. This study excludes the frequent occurrence of large genomic alterations in the BRCA1 gene in Finland. Here, again, Finland differs from other countries with a mixed population structure. Our results are in agreement with the common hypothesis that there are still unknown breast cancer susceptibility gene(s) that are responsible for breast cancer predisposition. 相似文献
9.
Hevein-specific recombinant IgE antibodies from human single-chain antibody phage display libraries 总被引:1,自引:0,他引:1
Laukkanen ML Mäkinen-Kiljunen S Isoherranen K Haahtela T Söderlund H Takkinen K 《Journal of immunological methods》2003,278(1-2):271-281
IgE antibodies distinctively recognising allergenic epitopes would be ideal reagents in immunodiagnostics to detect and quantify allergens, as well as for the development of allergy diagnostics and therapeutics. We have isolated recombinant human IgE antibodies specific for the major latex allergen, hevein, from antibody phage display libraries using a green fluorescent protein (GFP)-hevein fusion as a selection antigen. Human IgE phage display libraries were constructed by combining the IgE heavy chain genes to kappa and lambda light-chain genes which were isolated from lymphocytes of a latex allergic patient. The screening of antibody libraries resulted in the enrichment of two hevein-binding scFvs designated as 1A4 and 1C2. Both antibodies showed specific binding to the hevein that could be inhibited by both the recombinant GFP-hevein and native hevein isolated from latex examination gloves. The scFvs were prone to aggregate and, thus, for further characterisation, they were converted to Fab fragments with human IgG1 or IgE isotype. Similar hevein-binding properties of the 1A4 and 1C2 Fab fragments and human IgE serum pool, conventionally used in the detection of latex allergens, demonstrate the potential utility of these recombinant antibodies for the analysis of latex allergen. 相似文献
10.