全文获取类型
收费全文 | 109236篇 |
免费 | 10235篇 |
国内免费 | 5899篇 |
专业分类
耳鼻咽喉 | 885篇 |
儿科学 | 1877篇 |
妇产科学 | 1045篇 |
基础医学 | 7795篇 |
口腔科学 | 2318篇 |
临床医学 | 14126篇 |
内科学 | 11020篇 |
皮肤病学 | 1306篇 |
神经病学 | 3176篇 |
特种医学 | 3102篇 |
外国民族医学 | 19篇 |
外科学 | 8264篇 |
综合类 | 27112篇 |
现状与发展 | 30篇 |
一般理论 | 5篇 |
预防医学 | 12401篇 |
眼科学 | 1810篇 |
药学 | 13476篇 |
125篇 | |
中国医学 | 9806篇 |
肿瘤学 | 5672篇 |
出版年
2024年 | 423篇 |
2023年 | 1381篇 |
2022年 | 3284篇 |
2021年 | 4275篇 |
2020年 | 3818篇 |
2019年 | 2300篇 |
2018年 | 2405篇 |
2017年 | 3085篇 |
2016年 | 2429篇 |
2015年 | 4175篇 |
2014年 | 5694篇 |
2013年 | 6704篇 |
2012年 | 9740篇 |
2011年 | 10180篇 |
2010年 | 8984篇 |
2009年 | 7846篇 |
2008年 | 7987篇 |
2007年 | 7741篇 |
2006年 | 7153篇 |
2005年 | 5911篇 |
2004年 | 4098篇 |
2003年 | 3544篇 |
2002年 | 2878篇 |
2001年 | 2428篇 |
2000年 | 1956篇 |
1999年 | 1015篇 |
1998年 | 463篇 |
1997年 | 453篇 |
1996年 | 367篇 |
1995年 | 331篇 |
1994年 | 290篇 |
1993年 | 166篇 |
1992年 | 211篇 |
1991年 | 201篇 |
1990年 | 166篇 |
1989年 | 152篇 |
1988年 | 125篇 |
1987年 | 140篇 |
1986年 | 122篇 |
1985年 | 100篇 |
1984年 | 68篇 |
1983年 | 57篇 |
1982年 | 40篇 |
1981年 | 31篇 |
1980年 | 38篇 |
1979年 | 28篇 |
1978年 | 26篇 |
1973年 | 30篇 |
1972年 | 25篇 |
1958年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
71.
Objective To investigate the effect of recombinant human granulocyte macrophage colony stimulating factor (rhGM-CSF) as adjuvant on immune response in adults of non-and hyporesponders to hepatitis B vaccine. Methods Those who were once immunized with recombined yeast gene hepatitis B vaccine more than one standard scheme in two years and negative for hepatitis B markers were randomly sorted as group A and group B. 33 adults of group A were given hepatitis B vaccine 10 μg each time. The immune procedure was O, 1 and 6month. 34 adults of group B were given rhGM-CSF 300 μg for the first day, then 10 μg each time for routine immune. The blood samples were collected before the first injection and in 1, 2 and 8 months (T1, T2, TS)following the first injection to test Anti-HBs. Results Anti-HBs positive conversion rates of group A and B at T8 was 39.39% and 64.71% respectively(P=0.038). Anti-HBs levels of group B at TI, T2, T8 were(113.85±198.56) mIU/ml, (312.40±349.44) mIU/ml, (427.74±411. 58) mIU/ml (P=0.001). There was significant difference between group A and B in T8 Anti-HBs levels(P=0.010). Conclusion Better immune response was found in the group of rhGM-CSF with hepatitis B vaccine. So rhGM-CSF can induce the immune respond to hepatitis B vaccine. 相似文献
72.
73.
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
74.
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
75.
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
76.
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
77.
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
78.
79.
Ko JM Yau WL Chan PL Lung HL Yang L Lo PH Tang JC Srivastava G Stanbridge EJ Lung ML 《Genes, chromosomes & cancer》2005,43(3):284-293
Despite the abundant evidence of high allelic loss of chromosome arm 14q in human cancers, tumor-suppressor genes mapped to this chromosome have yet to be identified. To narrow the search for candidate genes, we performed monochromosome transfer of chromosome 14 into an esophageal carcinoma cell line, SLMT-1 S1. Statistically significant suppression of the tumorigenic potential of microcell hybrids containing the transferred chromosome 14 provided functional evidence that tumor-suppressive regions of chromosome 14 are essential for esophageal cancer. Tumor segregants emerging in nude mice during the tumorigenicity assay were analyzed by detailed PCR-microsatellite typing to identify critical nonrandomly eliminated regions (CRs). A 680-kb CR mapped to 14q32.13 and an approximately 2.2-Mb CR mapped to 14q32.33 were delineated. Dual-color BAC FISH analysis of microcell hybrids and tumor segregants verified the selective loss of the 14q32.13 region. In contrast, similar transfers of an intact chromosome 11 into SLMT-1 S1 did not significantly suppress tumor formation. These functional complementation studies showing the correlation of tumorigenic potential with critical regions of chromosome 14 validated the importance of the 14q32 region in tumor suppression in esophageal cancer. The present study also paved the path for further identification of novel tumor-suppressor genes that are relevant to the molecular pathogenesis of esophageal cancer. 相似文献
80.
Mitochondrial DNA and Y-Chromosome Variation in the Caucasus 总被引:7,自引:3,他引:7
I. Nasidze E. Y. S. Ling D. Quinque I. Dupanloup R. Cordaux S. Rychkov O. Naumova O. Zhukova N. Sarraf-Zadegan G. A. Naderi S. Asgary S. Sardas D. D. Farhud T. Sarkisian C. Asadov A. Kerimov M. Stoneking 《Annals of human genetics》2004,68(3):205-221
We have analyzed mtDNA HVI sequences and Y chromosome haplogroups based on 11 binary markers in 371 individuals, from 11 populations in the Caucasus and the neighbouring countries of Turkey and Iran. Y chromosome haplogroup diversity in the Caucasus was almost as high as in Central Asia and the Near East, and significantly higher than in Europe. More than 27% of the variance in Y‐haplogroups can be attributed to differences between populations, whereas mtDNA showed much lower heterogeneity between populations (less then 5%), suggesting a strong influence of patrilocal social structure. Several groups from the highland region of the Caucasus exhibited low diversity and high differentiation for either or both genetic systems, reflecting enhanced genetic drift in these small, isolated populations. Overall, the Caucasus groups showed greater similarity with West Asian than with European groups for both genetic systems, although this similarity was much more pronounced for the Y chromosome than for mtDNA, suggesting that male‐mediated migrations from West Asia have influenced the genetic structure of Caucasus populations. 相似文献