全文获取类型
收费全文 | 52479篇 |
免费 | 5503篇 |
国内免费 | 3169篇 |
专业分类
耳鼻咽喉 | 395篇 |
儿科学 | 859篇 |
妇产科学 | 637篇 |
基础医学 | 4786篇 |
口腔科学 | 979篇 |
临床医学 | 7330篇 |
内科学 | 6608篇 |
皮肤病学 | 581篇 |
神经病学 | 2015篇 |
特种医学 | 1638篇 |
外国民族医学 | 19篇 |
外科学 | 3531篇 |
综合类 | 11389篇 |
现状与发展 | 22篇 |
一般理论 | 5篇 |
预防医学 | 5393篇 |
眼科学 | 1234篇 |
药学 | 6128篇 |
72篇 | |
中国医学 | 4065篇 |
肿瘤学 | 3465篇 |
出版年
2024年 | 213篇 |
2023年 | 735篇 |
2022年 | 1712篇 |
2021年 | 2268篇 |
2020年 | 1932篇 |
2019年 | 1450篇 |
2018年 | 1475篇 |
2017年 | 1643篇 |
2016年 | 1379篇 |
2015年 | 2202篇 |
2014年 | 2893篇 |
2013年 | 3075篇 |
2012年 | 4372篇 |
2011年 | 4581篇 |
2010年 | 3670篇 |
2009年 | 3161篇 |
2008年 | 3405篇 |
2007年 | 3361篇 |
2006年 | 3166篇 |
2005年 | 2721篇 |
2004年 | 1936篇 |
2003年 | 1775篇 |
2002年 | 1579篇 |
2001年 | 1174篇 |
2000年 | 1052篇 |
1999年 | 743篇 |
1998年 | 446篇 |
1997年 | 415篇 |
1996年 | 328篇 |
1995年 | 306篇 |
1994年 | 253篇 |
1993年 | 124篇 |
1992年 | 212篇 |
1991年 | 190篇 |
1990年 | 158篇 |
1989年 | 143篇 |
1988年 | 114篇 |
1987年 | 135篇 |
1986年 | 106篇 |
1985年 | 86篇 |
1984年 | 62篇 |
1983年 | 54篇 |
1982年 | 29篇 |
1981年 | 30篇 |
1980年 | 34篇 |
1979年 | 25篇 |
1978年 | 25篇 |
1973年 | 29篇 |
1972年 | 23篇 |
1970年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
41.
Makoto Bannai Katsushi Tokunaga Ling Lin Atsuko Ogawa Kiyoshi Fujisawa Takeo Juji 《Human immunology》1996,46(2):107-113
We developed a system for discriminating HLA-B40, B18, B27, and B37 alleles using a two-step PCR method followed by SSCP analysis. Fragments (0.8 kb) including exon 2, intron 2, and exon 3 were amplified in the first PCR. We used two sets of primers, one specific for HLA-B60-related alleles and the other specific for HLA-B6l-related, B18, B27, and B37 alleles. No amplifications of other class I genes or pseudogenes were observed. In the second PCR, exon 2 and exon 3 were amplified separately, using diluents of the first PCR products as templates. HLA-B6l-related, B18, B27, B37, and B60-related alleles were clearly discriminated in the SSCP analysis of the second PCR products. In a population study in which B6l alleles were analyzed, B*4003 was detected in two Japanese individuals in addition to two B6l alleles previously reported to occur in Japanese, B*4002 and B*4006. The relative frequencies of B*4002, B*4006, and B*4003 in Japanese were 58, 35, and 6%, respectively. The individuals having B*4003 are the first non-South Americans in whom this allele has been detected. The SSCP banding patterns of 18 HLA-B60-positive Japanese population samples were identical to those of a B*40012 sample for both exon 2 and exon 3. We also demonstrated that the B37 allele occurring in some Japanese is B*3701. 相似文献
42.
43.
44.
Immune monitoring in whole blood using real-time PCR 总被引:7,自引:0,他引:7
Stordeur P Zhou L Byl B Brohet F Burny W de Groote D van der Poll T Goldman M 《Journal of immunological methods》2003,276(1-2):69-77
45.
46.
Two-dimensional dose distribution of 125I seeds 总被引:1,自引:0,他引:1
Two-dimensional dose distribution has been measured for the new (model 6711) 125I seeds used in interstitial implants. Two independent methods, using a silicon diode or thermoluminescent dosimeters, yielded identical results. At any given distance r from the seed center, the dose varies with theta, the angle relative to the seed's axis. Similarly, the r dependence of the dose distribution is different at various theta values. These observations can be qualitatively understood in terms of several factors, namely, source encapsulation, geometrical relationship, and attenuation and scatter. Empirical expressions which approximate the measured results have been developed to facilitate clinical dose distribution calculations. 相似文献
47.
Epitopes recognised by a panel of 23 anti-Fc gamma monoclonal antibodies (McAbs) have been subdivided into three groups each having a distinct topographical distribution. One group of mutually inhibitory McAbs are reactive with epitopes expressed on the fy "surface" of the C gamma 2 domain. A second group recognises epitopes in the region of arginine 355 of the C gamma 3 domain whilst the third group recognises epitopes expressed in the inter C gamma 2/C gamma 3 domain region--as evidenced by inhibition of Staphylococcus aureus protein A binding. An antibody of the latter group reactive with IgG1, 2, 4 and IgG3m(15,16) proteins but not IgG3m(5) or IgG3m(21) proteins allows histidine 435 to be identified as a critical residue for expression of the epitope recognised by this antibody. 相似文献
48.
In the mitral valve, regional variations in structure and material properties combine to affect the biomechanics of the entire valve. Previous biaxial testing has shown that mitral valve leaflet tissue is highly extensible, and exhibits nonlinear, anisotropic material properties. In this study, experimental measurements of mitral valve leaflet deformation under quasi-static pressure loading were performed on isolated porcine hearts. Biplane video images of markers placed on the anterior leaflet surface were used to reconstruct the 3D position of the markers at several pressure levels over the physiological range. A least-squares finite-element method was used to fit parametric models to the markers and to calculate the deformation over the surface. The results showed that the leaflet deformations were anisotropic, exhibiting a large nonhomogeneous radial stretch and a small circumferential stretch. This information can be used to better understand how the valve deforms under physiological loading, and to help design treatments for valve problems, such as mitral regurgitation. 相似文献
49.
Luo Ling Xu Daniel W. McVicar Adit Ben-Baruch Douglas B. Kuhns James Johnston Joost J. Oppenheim Ji Ming Wang 《European journal of immunology》1995,25(9):2612-2617
The diversity of monocyte chemotactic protein (MCP)3 target cell types, as well as the capacity of MCP3 to desensitize leukocyte responses to other CC chemokines, suggested that MCP3 may interact with multiple CC chemokine receptors. The purpose of this study is to establish how MCP3 binds and activates monocytes and neutrophils. We show that human monocytes exhibit high-affinity binding for 125I-MCP3 with an estimated Kd of 1–3 nM and about 10000 binding sites/cell. The binding of 125I-MCP3 to monocytes was progressively less well competed by CC chemokines macrophage inflammatory protein (MIP)lα (Kd = 5–10 nM), RANTES (Kd = 5–10 nM), MCP1 (monocyte chemoattractant and activating factor, or MCAF) (Kd = 60 nM) and MIP1β (Kd > 100 nM). On the other hand, unlabeled MCP3 displaced the binding of radiolabeled MIP1α, RANTES, MCP1 and MIP1β as effectively as the isologous CC chemokines. In agreement with the binding data, pretreatment of monocytes with MCP3 completely desensitized the calcium flux in response to MIP1α and RANTES. However, MIP1α and RANTES failed to desensitize the response of monocytes to MCP3. MCP3 and MCP1 partially desensitized each other's effects on monocytes. These binding and cross-desensitization results suggest that MCP3 binds and signals through other binding sites in addition to those shared with MIP1α, RANTES and MCP1. The unidirectional competition for MIP1β binding and signaling by MCP3 suggests the existence of an as-yet unidentified site for MCP3 shared with MIP1β. The existence of another unique binding site(s) for MCP3 was further shown by the failure of any of the other CC chemokines to compete effectively for MCP3 binding on neutrophils. MCP3 in our study was also the only human CC chemokine that consistently chemoattracted neutrophils. These results suggest that MCP3 is a ligand that can bind and activate a broad range of target cells through receptors shared by other CC chemokines as well as its own receptor. 相似文献
50.
Hypothalamic neurons producing growth hormone-releasing factor (GRF) have been characterized by immunohistochemistry in monkey hypothalamus, using an antiserum raised against hpGRF1-40, a peptide with GRF activity isolated from a human pancreatic tumor. Cell bodies with hpGRF immunoreactivity were found in arcuate and ventromedial nuclei. From these neurons, bundles of fibers innervate median eminence and appear to terminate in contact with portal vessels. In addition to median eminence, hpGRF immunoreactive fibers were found mostly in the anterior hypothalamus and the arcuate and ventromedial nuclei where they give perineuronal endings. These results correlate with earlier physiological data on hypothalamic control of growth hormone secretion and suggest that GRF is also involved in interneuronal relationships related or unrelated to neurohumoral control of pituitary secretions. 相似文献