全文获取类型
收费全文 | 164287篇 |
免费 | 15371篇 |
国内免费 | 7452篇 |
专业分类
耳鼻咽喉 | 1106篇 |
儿科学 | 3270篇 |
妇产科学 | 1918篇 |
基础医学 | 30744篇 |
口腔科学 | 4018篇 |
临床医学 | 11780篇 |
内科学 | 24718篇 |
皮肤病学 | 2747篇 |
神经病学 | 15058篇 |
特种医学 | 4067篇 |
外国民族医学 | 56篇 |
外科学 | 11482篇 |
综合类 | 22861篇 |
现状与发展 | 35篇 |
一般理论 | 1篇 |
预防医学 | 7465篇 |
眼科学 | 2130篇 |
药学 | 21051篇 |
38篇 | |
中国医学 | 5367篇 |
肿瘤学 | 17198篇 |
出版年
2024年 | 441篇 |
2023年 | 2520篇 |
2022年 | 5594篇 |
2021年 | 6659篇 |
2020年 | 5697篇 |
2019年 | 5842篇 |
2018年 | 5571篇 |
2017年 | 5724篇 |
2016年 | 5723篇 |
2015年 | 6285篇 |
2014年 | 9187篇 |
2013年 | 10420篇 |
2012年 | 8892篇 |
2011年 | 10778篇 |
2010年 | 8719篇 |
2009年 | 8807篇 |
2008年 | 8988篇 |
2007年 | 8477篇 |
2006年 | 7663篇 |
2005年 | 7142篇 |
2004年 | 6214篇 |
2003年 | 5462篇 |
2002年 | 4454篇 |
2001年 | 3933篇 |
2000年 | 3299篇 |
1999年 | 2913篇 |
1998年 | 2660篇 |
1997年 | 2377篇 |
1996年 | 1968篇 |
1995年 | 1769篇 |
1994年 | 1496篇 |
1993年 | 1280篇 |
1992年 | 1004篇 |
1991年 | 877篇 |
1990年 | 753篇 |
1989年 | 608篇 |
1988年 | 549篇 |
1987年 | 531篇 |
1986年 | 616篇 |
1985年 | 841篇 |
1984年 | 778篇 |
1983年 | 599篇 |
1982年 | 608篇 |
1981年 | 510篇 |
1980年 | 461篇 |
1979年 | 384篇 |
1978年 | 235篇 |
1977年 | 194篇 |
1976年 | 200篇 |
1975年 | 123篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
ALVARO MARTÍNEZ DEL POZO MARIA GASSET MERCEDES O
ADERRA JOS G. GAVILANES 《Chemical biology & drug design》1989,34(5):416-422
α-Sarcin binds one Zn(II) cation per protein molecule, with a Kd value of 0.9 mM, determined by equilibrium dialysis experiments. Ca(II), Mg(II), and Mn(II) do not bind to α-sarcin. Cd(II) and Co(II) also behave as Zn(II). The binding produces local modifications on the protein conformation affecting the microenvironment of tryptophan residues. The three cations modify the fluorescence emission of the protein. The near-u. v. circular dichroism spectrum of the protein is also altered. The binding of Zn(II) and related cations does not modify the secondary structure of the protein. The ribonucleolytic activity of a-sarcin is inhibited upon Zn(II) binding, but no alteration of the ability of the protein to aggregate phospholipid vesicles has been observed. 相似文献
42.
Regulation of erythropoietin production 总被引:6,自引:0,他引:6
43.
PRO 1000 V3型心电监护仪LCD逆变器的升级及注意事项 总被引:1,自引:0,他引:1
介绍了该型心电监护仪黑屏故障的常见原因,对升级前后的LCD逆变器电路作了对比分析,并详细介绍了升级更换的方法和注意事项。 相似文献
44.
高度近视的病因学研究进展 总被引:9,自引:0,他引:9
高度近视发生的内因、外因,包括遗传倾向,相关基因定位,巩膜胶原白体免疫学说,视网膜生物活性物质失调学说,环境因素等,本研究就这些因素对高度近视发病的影响做一综述。现统一的认识有:①高度近视具有明显的遗传倾向。②迄今为止,已找到4个高度近视相关基因,它们的遗传方式均为常染色体显性遗传。③高度近视的巩膜组织病理改变和胶原代谢障碍引发了人们对高度近视免疫相关基因的深入研究。已发现HLAⅡ类基因与部分高度近视具有相关性。④视网膜中存在的生物活性物质直接或间接参与了形觉剥夺性近视的形成。⑤环境因素并非高度近视发病的决定因素,它仅起一定程度的促进作用。将今后的工作重点放在高度近视基因定位的研究,基因表达的调控及巩膜胶原代谢、网膜生物活性物质之间的关系研究上,无疑会进一步揭示高度近视的病因,为防治高度近视开辟新途径。 相似文献
45.
46.
Giorgio Ciprandi Mara De Amici Simone Negrini Gianluigi Marseglia Maria Angela Tosca 《International immunopharmacology》2009,9(10):1247-1249
Two new T cell subsets may be involved in allergic rhinitis (AR) pathogenesis: Th17 and T regulatory cells, mainly producing IL-17 and TGF-β respectively. Successful Sublingual Immunotherapy (SLIT) induces relevant immunological changes, thus the aim of this study was to evaluate serum IL-17 and TGF-β levels in AR patients treated with SLIT for 2 years. Patients' blood samples were collected before initiating SLIT (baseline), three months after the end of the first pre-seasonal SLIT course, and at the end of the second pre-seasonal course. IL-17 was detectable only in the most severe allergic patients. SLIT significantly induced an increase in serum TGF-β levels. There was moreover a significant relationship between TGF-β and symptom severity and drug use at the end of the study. Therefore, this study provides clinically relevant evidence that two pre-seasonal SLIT courses may significantly affect serum TGF-β levels. 相似文献
47.
Chandipura virus (CHPV) has emerged as an important pediatric encephalitis-causing pathogen with very high mortality in India. No specific vaccine or treatment is available till date. We attempted to prepare a candidate vaccine employing recombinant CHPV Glycoprotein (rGp). The Glycoprotein gene (G-gene) of CHPV was expressed using Baculovirus expression system. The rGp was purified by HPLC and used for mice immunization, 3 doses, and 4 weeks apart. One microgram rGp was found to be optimum. Sero-conversion was observed as early as 2nd week by detecting anti-CHPV IgG antibodies. Antibody titres were immunogen-concentration dependent. Intracerebral challenge of the immunized mice with 100 LD50 of the homologous strain demonstrated 90% protection. In in vitro neutralization, antibodies from the immunized mice were able to neutralize heterologous viruses. There was 60% T cell proliferation observed against rGp in immunized mice. The study shows that rGp induces both arms of immune response and represents an ideal vaccine candidate for further evaluations. 相似文献
48.
瘢痕疙瘩是烧伤外科研究的重要课题,其形成机制尚未完全明确,本文就其在遗传机制、免疫作用、细胞增殖与胶原代谢、细胞因子等方面的研究进展进行综述。 相似文献
49.
螺旋CT三维重建成像在先天性高肩胛症手术方式选择中的作用 总被引:4,自引:2,他引:2
[目的]探讨螺旋CT三维重建技术在先天性高肩胛症分度和手术方式选择中的作用。[方法]22例先天性高肩胛症术前应用螺旋CT对病变部位进行扫描并三维重建,测量以肩胛骨肩胛冈内侧缘为参照点,两侧肩胛骨高度差。根据测量结果依据Cavendish分度将其分类,并根据三维重建成像选择不同的矫形手术术式。[结果]本组22例病人,随访2—4年,外观及功能均有不同程度的改善,未出现神经、血管和椎体等的损伤。[结论]根据螺旋CT扫描和三维重建检查结果,术前即可直观的明确先天性高肩胛症的病变程度,相互关系,伴发畸形,患侧肩胛骨与正常对侧肩胛骨的外观差异等,便于手术操作方案的制定,避免了手术操作的盲目性,减少医源性并发症的发生。 相似文献
50.
Terry Joe Sprinkle Julia F. Agee Russell B. Tippins C. Richard Chamberlain Guy B. Faguet George H. DeVries 《Brain research》1987,426(2):349-357
Monoclonal antibodies against human and bovine 2′:3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) were generated by fusing FOX-NY myeloma cells with spleen cells from RBF/Dn mice previously immunized with the purified brain antigens. The enzyme isolated from bovine brain was quite basic, with an isoelectric point of 9.71 and both the bovine and human enzymes consisted of a closely spaced doublet at approximately 44 and 46 kDa on SDS-PAGE. Six monoclonals were identified as strongly recognizing the enzyme on both ELISA plates and on immunoblots of whole brain protein. Four monoclonals very weakly cross-reacted with guinea pig myelin basic protein. In contrast with two previous reports, some of our monoclonal antibodies did immunostain 2 or 3 protein bands in peripheral nerve, two bands closely corresponding to those immunostained in central nervous system (CNS) myelin, the Wolfgram protein fraction and in acetone powders of whole brain. Each of the 6 monoclonals reacting strongly on immunoblots recognized the enzyme in from 2 to 5 of the species examined (human, bovine, rat, mouse and rabbit). In addition, all 6 monoclonals that immunostained the enzyme in whole brain, myelin and Wolfgram protein immunoblots recognized both CNP1 (44 kDa) and CNP2 (46 kDa). The two closely spaced protein bands observed on SDS-PAGE and previously stained on immunoblots of CNS CNPase using polyvalent rabbit anti-bovine CNPase antisera, and now different monoclonal antibodies, appear to be immunologically related and to contain highly conserved sequences. 相似文献