全文获取类型
收费全文 | 9142篇 |
免费 | 589篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 53篇 |
儿科学 | 208篇 |
妇产科学 | 211篇 |
基础医学 | 1133篇 |
口腔科学 | 122篇 |
临床医学 | 898篇 |
内科学 | 2044篇 |
皮肤病学 | 80篇 |
神经病学 | 631篇 |
特种医学 | 498篇 |
外科学 | 1546篇 |
综合类 | 111篇 |
一般理论 | 3篇 |
预防医学 | 643篇 |
眼科学 | 282篇 |
药学 | 700篇 |
中国医学 | 26篇 |
肿瘤学 | 570篇 |
出版年
2023年 | 71篇 |
2022年 | 127篇 |
2021年 | 247篇 |
2020年 | 122篇 |
2019年 | 204篇 |
2018年 | 236篇 |
2017年 | 167篇 |
2016年 | 175篇 |
2015年 | 206篇 |
2014年 | 308篇 |
2013年 | 372篇 |
2012年 | 605篇 |
2011年 | 617篇 |
2010年 | 352篇 |
2009年 | 299篇 |
2008年 | 452篇 |
2007年 | 513篇 |
2006年 | 440篇 |
2005年 | 469篇 |
2004年 | 433篇 |
2003年 | 412篇 |
2002年 | 370篇 |
2001年 | 176篇 |
2000年 | 208篇 |
1999年 | 146篇 |
1998年 | 78篇 |
1997年 | 52篇 |
1996年 | 45篇 |
1995年 | 44篇 |
1993年 | 44篇 |
1992年 | 117篇 |
1991年 | 77篇 |
1990年 | 101篇 |
1989年 | 98篇 |
1988年 | 112篇 |
1987年 | 91篇 |
1986年 | 62篇 |
1985年 | 82篇 |
1984年 | 60篇 |
1983年 | 74篇 |
1981年 | 39篇 |
1979年 | 50篇 |
1978年 | 48篇 |
1975年 | 48篇 |
1974年 | 64篇 |
1972年 | 55篇 |
1971年 | 50篇 |
1970年 | 40篇 |
1968年 | 38篇 |
1967年 | 40篇 |
排序方式: 共有9759条查询结果,搜索用时 15 毫秒
61.
Elizabeth Rudolph Katherine A. Kaiser Marjorie J. Corrigan 《Public health nursing (Boston, Mass.)》1987,4(2):89-98
An evaluative research study was conducted to examine the construct validity and applicability of a selected clinical-performance-evaluation tool. The tool was designed for baccalaureate students in a community health nursing course. Eighteen senior students functioning in two urban clinical agencies participated in the study. Data were collected at two evaluation points over one semester. Results indicated strong support for construct validity of the tool. This finding suggests a high level of correlation between theoretical concepts and clinical practice. Recommendations for use of the clinical performance evaluation tool are discussed. 相似文献
62.
D Kaiser 《Zentralblatt für Chirurgie》1989,114(19):1281-1286
Infrared coagulation (IRC) is a reliable method to stop surgical bleeding from the thoracic wall and proves to be superior to other forms of coagulation in this area. In pulmonary parenchyma IRC is used for sealing of parenchymal surfaces after atypical resections. Emphysematous bullae may be coagulated with IRC instead of over-swan. A main advantage in using IRC is that the surgical area not necessarily needs to be "dry" for application of IRC. Forced pressing of the IRC-applicator against the tissue prevents dissipation of light energy via running blood. There are no superficial carbonisations, instead there is coagulation inside the tissue. 相似文献
63.
Mosaic ring 12p and total anomalous pulmonary venous return 总被引:1,自引:0,他引:1
Harris DL Siu BL Hummel M Harbert K Senft J Sargent L Wenger SL 《American journal of medical genetics. Part A》2004,131(1):91-93
An infant born with total anomalous pulmonary venous return (TAPVR) was found to have an extra chromosome present as a small ring. Spectral karyotyping and FISH analysis identified the material as a duplication involving the short arm of chromosome 12. Previous cases describing a variety of cytogenetic abnormalities that have been associated with TAPVR are reviewed along with prior cases of duplication 12p with their associated findings. We believe ours is the first case to report the occurrence of mosaic ring 12p and its association with TAPVR. 相似文献
64.
WIF1, a component of the Wnt pathway, is down-regulated in prostate, breast, lung, and bladder cancer 总被引:19,自引:0,他引:19
65.
Husaini BA Sherkat DE Levine R Bragg R Van CA Emerson JS Mentes CM 《Journal of the National Medical Association》2002,94(2):100-106
This study examines the effectiveness of breast cancer screening education programs on mammography rates among African-American women 40 years of age and over. We conducted two types of educational programs in community settings, primarily in African-American churches. Three-month follow-up interviews were used to determine whether women who participated in programming were more likely to get a mammogram if they had not had a mammogram in the last year. Our results demonstrate that the educational programs significantly increased the likelihood of getting a mammogram when compared to a control group that received no educational programming. Further, we found that the programs were effective for motivating breast cancer screening in housing projects as well as in the churches, and that the effectiveness of the programs remained even when we controlled for socioeconomic status, depression, and age. 相似文献
66.
Pete Kaiser Tuang Yeow Poh Lisa Rothwell Stuart Avery Sucharitha Balu Uday S Pathania Simon Hughes Marianne Goodchild Shaun Morrell Michael Watson Nat Bumstead Jim Kaufman John R Young 《Journal of interferon & cytokine research》2005,25(8):467-484
As most mechanisms of adaptive immunity evolved during the divergence of vertebrates, the immune systems of extant vertebrates represent different successful variations on the themes initiated in their earliest common ancestors. The genes involved in elaborating these mechanisms have been subject to exceptional selective pressures in an arms race with highly adaptable pathogens, resulting in highly divergent sequences of orthologous genes and the gain and loss of members of gene families as different species find different solutions to the challenge of infection. Consequently, it has been difficult to transfer to the chicken detailed knowledge of the molecular mechanisms of the mammalian immune system and, thus, to enhance the already significant contribution of chickens toward understanding the evolution of immunity. The availability of the chicken genome sequence provides the opportunity to resolve outstanding questions concerning which molecular components of the immune system are shared between mammals and birds and which represent their unique evolutionary solutions. We have integrated genome data with existing knowledge to make a new comparative census of members of cytokine and chemokine gene families, distinguishing the core set of molecules likely to be common to all higher vertebrates from those particular to these 300 million-year-old lineages. Some differences can be explained by the different architectures of the mammalian and avian immune systems. Chickens lack lymph nodes and also the genes for the lymphotoxins and lymphotoxin receptors. The lack of functional eosinophils correlates with the absence of the eotaxin genes and our previously reported observation that interleukin- 5 (IL-5) is a pseudogene. To summarize, in the chicken genome, we can identify the genes for 23 ILs, 8 type I interferons (IFNs), IFN-gamma, 1 colony-stimulating factor (GM-CSF), 2 of the 3 known transforming growth factors (TGFs), 24 chemokines (1 XCL, 14 CCL, 8 CXCL, and 1 CX3CL), and 10 tumor necrosis factor superfamily (TNFSF) members. Receptor genes present in the genome suggest the likely presence of 2 other ILs, 1 other CSF, and 2 other TNFSF members. 相似文献
67.
Heterozygous carriers of mutations in the BRCA2 gene have a high risk of developing breast and other cancers. In these individuals, BRCA2 appears to act as a tumour suppressor gene, in that loss of the wild type allele is frequently observed within tumours, leading to loss of BRCA2 function. Because BRCA2 functions in DNA repair via homologous recombination, this leads to genomic instability. However, it is unclear whether loss of the wild type allele is stochastic or if heterozygosity for BRCA2 mutation carries a phenotype that contributes to tumorigenic progression. Here we demonstrate that, in a specific vertebrate cell type, the chicken B cell line DT40, heterozygosity for a BRCA2 mutation has a distinct phenotype. This is characterized by a reduced growth rate, increased cell death, heightened sensitivity to specific DNA damaging agents and reduced RAD51 focus formation after irradiation. Thus in certain cell types, genome instability might be driven directly by heterozygosity for BRCA2 mutation. 相似文献
68.
Human immunodeficiency virus is undoubtedly the causative agent of AIDS. The understanding of HIV-1 pathogenesis is essential to develop and maintain antiretroviral treatment and vaccination. Since the first isolation of HIV-1 in cell culture, thousands of publications dealing with HIV and/or AIDS per year were released. In this review we give a basic overview of the virology of HIV-1 including the functions of the different HIV-1 proteins required for effective viral replication. Moreover, we summarize the interactive processes between HIV-1 and its target cells. Finally, the HIV-1 specific immune response and the current status of antiretroviral therapy are briefly described in this review. 相似文献
69.
70.
Streptococcus pyogenes infection in mouse skin leads to a time-dependent up-regulation of protein H expression
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Streptococcus pyogenes protein H (sph) is an immunoglobulin-binding protein present in the Mga regulon of certain M1 serotype isolates. Although sph is present in many strains, it is frequently not expressed. In this paper we show that protein H was highly expressed after bacteria were injected into the skin of mice and were recovered from the blood, kidney, or spleen at various times postinfection. The percentage of protein H-positive colonies increased with time, reaching 100% in the spleen and kidney within 24 to 72 h postinfection. The up-regulation of sph expression was also observed in a mga mutant. 相似文献