全文获取类型
收费全文 | 9518篇 |
免费 | 916篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 143篇 |
儿科学 | 274篇 |
妇产科学 | 164篇 |
基础医学 | 1189篇 |
口腔科学 | 361篇 |
临床医学 | 918篇 |
内科学 | 2063篇 |
皮肤病学 | 135篇 |
神经病学 | 1068篇 |
特种医学 | 216篇 |
外科学 | 1418篇 |
综合类 | 212篇 |
一般理论 | 12篇 |
预防医学 | 1060篇 |
眼科学 | 250篇 |
药学 | 476篇 |
中国医学 | 2篇 |
肿瘤学 | 487篇 |
出版年
2021年 | 116篇 |
2019年 | 93篇 |
2018年 | 152篇 |
2017年 | 98篇 |
2016年 | 80篇 |
2015年 | 118篇 |
2014年 | 169篇 |
2013年 | 383篇 |
2012年 | 425篇 |
2011年 | 447篇 |
2010年 | 251篇 |
2009年 | 246篇 |
2008年 | 467篇 |
2007年 | 535篇 |
2006年 | 501篇 |
2005年 | 506篇 |
2004年 | 526篇 |
2003年 | 491篇 |
2002年 | 512篇 |
2001年 | 87篇 |
2000年 | 89篇 |
1999年 | 73篇 |
1998年 | 107篇 |
1997年 | 111篇 |
1996年 | 92篇 |
1995年 | 80篇 |
1994年 | 86篇 |
1993年 | 96篇 |
1992年 | 83篇 |
1991年 | 79篇 |
1990年 | 60篇 |
1989年 | 86篇 |
1988年 | 88篇 |
1987年 | 61篇 |
1986年 | 64篇 |
1985年 | 91篇 |
1984年 | 119篇 |
1983年 | 118篇 |
1982年 | 159篇 |
1981年 | 146篇 |
1980年 | 160篇 |
1979年 | 100篇 |
1978年 | 123篇 |
1977年 | 112篇 |
1976年 | 105篇 |
1975年 | 84篇 |
1974年 | 67篇 |
1973年 | 82篇 |
1972年 | 75篇 |
1964年 | 66篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
Gaye?T?Adams Harold?Snieder Virgil?C?McKie Betsy?Clair Donald?Brambilla Robert?J?Adams Ferdane?Kutlar Abdullah?KutlarEmail author 《BMC medical genetics》2003,4(1):6
Background
The phenotypic heterogeneity of sickle cell disease is likely the result of multiple genetic factors and their interaction with the sickle mutation. High transcranial doppler (TCD) velocities define a subgroup of children with sickle cell disease who are at increased risk for developing ischemic stroke. The genetic factors leading to the development of a high TCD velocity (i.e. cerebrovascular disease) and ultimately to stroke are not well characterized. 相似文献82.
Amara RR Ibegbu C Villinger F Montefiori DC Sharma S Nigam P Xu Y McClure HM Robinson HL 《Virology》2005,343(2):246-255
Here, we study immune responses in four DNA/MVA-vaccinated macaques following an SHIV-89.6P challenge and a subsequent CD8 cell depletion. Both post-challenge and post-depletion peaks of viremia contracted with the expansion, or re-emergence, of CD8 T cells. Post-depletion, CD8 cells expanded in the presence of higher levels of neutralizing Ab and CD4 help than post-challenge and had superior maturational characteristics as measured by expression of the anti-apoptotic protein Bcl-2, the IL-7 receptor CD127 and co-production of IFN-gamma and IL-2. Pre-challenge and pre-depletion titers of neutralizing Ab correlated inversely with peaks of viremia and directly with peaks for anti-viral CD4 cells. Thus, our results reveal CD8 cells playing a central role, and neutralizing Ab, a supporting role in SHIV-89.6P control. They also suggest a dynamic relationship between neutralizing Ab, antigen load and anti-viral CD4 cells in the maturation of high-quality anti-viral CD8 T cells. 相似文献
83.
84.
85.
Steven O. Schwartz Harold M. Schoolman 《Journal of molecular medicine (Berlin, Germany)》1960,38(6):249-254
Ohne ZusammenfassungAus dem Englischen übersetzt vonW. Stich, München. 相似文献
86.
Richard Meehan Ulric Duncan Laureen Neale Gerald Taylor Harold Muchmore Nan Scott Keith Ramsey Eric Smith Paul Rock Randall Goldblum Charles Houston 《Journal of clinical immunology》1988,8(5):397-406
We investigated the effects on immune function after progressive hypobaric hypoxia simulating an ascent to 25,000 ft (7620 m) over 4 weeks. Multiple simultaneousin vitro andin vivo immunologic variables were obtained from subjects at sea level, 7500 ft (2286 m), and 25,000 ft during a decompression chamber exposure. Phytohemag-glutinin-stimulated thymidine uptake and protein synthesis in mononuclear cells were reduced at extreme altitudes. Mononuclear-cell subset analysis by flow cytometry disclosed an increase in monocytes without changes in B cells or T-cell subsets. Plasma IgM and IgA but not IgG levels were increased at altitudes, whereas pokeweed mitogen-stimulatedin vitro IgG, IgA, and IgM secretion was unchanged. During exposure to 25,000 ft,in vitro phytohemagglutinin-stimulated interferon production and natural killer-cell cytotoxicity did not change statistically, but larger intersubject differences occurred. IgA and lysozyme levels (nasal wash) and serum antibodies to nuclear antigens were not influenced by altitude exposure. These results suggest that T-cell activation is blunted during exposure to severe hypoxemia, whereas B-cell function and mucosal immunity are not. Although the mechanism of alteredin vitro immune responsiveness after exposure to various environmental stressors has not been elucidated in humans, hypoxia may induce alterations in immune regulation as suggested byin vitro immune assays of effector-cell function.Some of this study's results were presented as an abstract at the FASEB meeting in St. Louis, Missouri, 1986. 相似文献
87.
Harold J. Cook 《Medical history》1990,34(4):447-448
88.
89.
90.
Ronald L. Arenson Dev P. Chakraborty Sridhar B. Seshadri Harold L. Kundel 《Journal of digital imaging》2003,16(1):142-162
Picture archiving and communication systems (PACS) are expected to convert film-based radiology into a computer-based digital environment, with associated cost savings and improved physician communication. The digital workstation will be used by physicians to display these soft-copy images; however, difficult technical challenges must be met for the workstation to compete successfully with the familiar viewbox. Issues relating to image perception and the impact on physicians practice must be carefully considered. The spatial and contrast resolutions required vary according to imaging modality, type of procedure, and class of user. Rule-based software allows simple physician interaction and speeds image display. A consensus appears to be emerging concerning the requirements for the PACS workstation. Standards such as the American College of Radiology/National Electrical Manufacturers Association Digital Imaging and Communication Standard are facilitating commercial applications. Yet much careful study is needed before PACS workstations will be fully integrated into radiology departments.
Abbreviations: CRT = cathode ray tube, H&D = Hurter and Drifield, PACS = picture archiving and communication system, ROC = receiver operating characteristic, S/N = signal-to-noise ratio. Partially supported by grant HL-33332 from the National Heart, Lung, and Blood institute, U.S. Public Health Service. Address reprint requests to R.L.A. Copyright © 1990 by the Radiological Society of North America. Radiology 176:303-315, 1990. Reprinted with permission. 相似文献