全文获取类型
收费全文 | 20331篇 |
免费 | 1158篇 |
国内免费 | 614篇 |
专业分类
耳鼻咽喉 | 127篇 |
儿科学 | 485篇 |
妇产科学 | 235篇 |
基础医学 | 2711篇 |
口腔科学 | 221篇 |
临床医学 | 1138篇 |
内科学 | 3708篇 |
皮肤病学 | 226篇 |
神经病学 | 1372篇 |
特种医学 | 603篇 |
外国民族医学 | 2篇 |
外科学 | 2351篇 |
综合类 | 1939篇 |
现状与发展 | 2篇 |
预防医学 | 2416篇 |
眼科学 | 198篇 |
药学 | 2599篇 |
2篇 | |
中国医学 | 864篇 |
肿瘤学 | 904篇 |
出版年
2023年 | 206篇 |
2022年 | 698篇 |
2021年 | 785篇 |
2020年 | 523篇 |
2019年 | 887篇 |
2018年 | 944篇 |
2017年 | 689篇 |
2016年 | 448篇 |
2015年 | 598篇 |
2014年 | 882篇 |
2013年 | 1067篇 |
2012年 | 1039篇 |
2011年 | 1594篇 |
2010年 | 1460篇 |
2009年 | 852篇 |
2008年 | 669篇 |
2007年 | 674篇 |
2006年 | 586篇 |
2005年 | 493篇 |
2004年 | 412篇 |
2003年 | 376篇 |
2002年 | 360篇 |
2001年 | 336篇 |
2000年 | 278篇 |
1999年 | 264篇 |
1998年 | 214篇 |
1997年 | 231篇 |
1996年 | 175篇 |
1995年 | 161篇 |
1994年 | 150篇 |
1993年 | 127篇 |
1992年 | 118篇 |
1991年 | 95篇 |
1990年 | 94篇 |
1989年 | 86篇 |
1988年 | 79篇 |
1986年 | 77篇 |
1985年 | 337篇 |
1984年 | 464篇 |
1983年 | 335篇 |
1982年 | 319篇 |
1981年 | 304篇 |
1980年 | 290篇 |
1979年 | 248篇 |
1978年 | 196篇 |
1977年 | 156篇 |
1976年 | 230篇 |
1975年 | 148篇 |
1974年 | 127篇 |
1973年 | 101篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Norio Niikawa 《Journal of human genetics》1996,41(4):351-361
Summary Genomic imprinting is a biological phenomenon determined by an evolutionally acquired, underlying system that may control harmonious development and growth in mammals. It is also relevant to some genetic disorders in man. In this article, lines of biological evidence of imprinting, characteristics of the mouse and human imprinted genes, and findings and mechanisms on the occurrence of several human imprinting disorders are reviewed. 相似文献
62.
目的 构建甲型副伤寒杆菌(Salmonella paratyphi A)H1a基因原核表达系统,确定表达产物rH1a免疫原性和保护作用,检测甲型副伤寒杆菌临床菌株H1a基因携带和表达情况。方法 采用高保真PCR从甲型副伤寒杆菌临床株JH01中扩增H1a基因,T-A克隆后测序,构建H1a基因原核表达系统pET32a-H1a-E.coli B121DE3。采用SDS-PAGE和BioRad凝胶图象分析系统检查rH1a表达情况,Ni-NTA亲和层析法收集rH1a。采用Western blot鉴定其免疫反应性和免疫原性。建立PCR和ELISA检测98株甲型副伤寒杆菌临床菌株H1a基因携带和表达频率。观察rH1a对甲型副伤寒杆菌50001株感染小鼠的免疫保护作用。结果 与报道的相关序列比较,所克隆的H1a基因核苷酸和氨基酸序列相似性均为99.59%。rH1a表达量为细菌总蛋白的60%左右。甲型副伤寒杆菌全菌抗血清能识别rH1a并与之结合。rH1a免疫家兔可产生抗体。100%(98/98)甲型副伤寒杆菌临床菌株均含有H1a基因并表达H1a。500μg rH1a灌喂或皮下注射免疫小鼠受甲型副伤寒杆菌50001株攻击后的存活率均为50.0%,若加入5μg rLTB,存活率分别上升至75.0%和66.7%。结论 本研究成功地从甲型副伤寒杆菌临床菌株中构建了H1a基因高效原核表达系统。rH1a有良好的免疫原性和一定的免疫保护作用。甲型副伤寒杆菌临床菌株广泛存在H1a基因并高频率表达。 相似文献
63.
64.
Jennifer A. Ruskey Lior Greenbaum Léanne Roncière Armaghan Alam Dan Spiegelman Christopher Liong Oren A. Levy Cheryl Waters Stanley Fahn Karen S. Marder Wendy Chung Gilad Yahalom Simon Israeli-Korn Vered Livneh Tsvia Fay-Karmon Roy N. Alcalay Sharon Hassin-Baer Ziv Gan-Or 《European journal of medical genetics》2019,62(1):65-69
Background
Variants in GBA are the most common genetic risk factor for Parkinson's disease (PD), and are especially prevalent in the Ashkenazi Jewish (AJ) population. However, most studies on GBA in AJ genotype only seven selected Gaucher-associated pathogenic variants rather than sequencing the whole gene, which may leave carriers of PD-associated GBA variants undiscovered.Methods
GBA was fully sequenced using molecular inversion probes (MIPs) and Sanger sequencing in 735 AJ PD patients and 662 AJ controls, from Israel and New York. Additional AJ control data (n?=?3044) from the Inflammatory Bowel Disease Exome Portal was used.Results
Full GBA sequencing increased the number of variants discovered by 17.4%, compared to targeted genotyping. An additional 17 PD patients were identified with GBA-associated PD. The p.E326K variant was found in 1.6% of AJ PD patients, making it the second most common PD-associated GBA variant in AJ. GBA variants were found in 18% of PD patients and 7.5% of controls (OR?=?2.7, 95%CI?=?1.9–3.8, p?<?0.0001).Conclusion
Without full sequencing of GBA, or at minimum including p.E326K in the genotyping panel, a significant proportion of variant carriers go undiscovered and may be incorrectly assigned as non-carriers in studies or clinical trials. 相似文献65.
Giorgio Torelli Eloisa Milla Leonard I. Kleinman Alide Faelli 《Pflügers Archiv : European journal of physiology》1973,342(3):219-230
Summary The relationship between sodium reabsorption and oxygen consumption was studied in an isolated rabbit kidney preparation perfused with blood at 37, 28 and 19° C. When the temperature was lowered from 37° C to 28° C and to 19°C the rate of oxygen consumption and of the maximal P.A.H. excretion (Tm P.A.H.) decreased more than that of sodium reabsorption.TheQ
10 for sodium reabsorption is about 1.8, while that for maximal P.A.H. excretion is 2.5. Some hypothesis on the possible mechanisms of the lowQ
10 of the Na+ reabsorption are forwarded.Preliminary reports have been published [Boll. Soc. Ital. Biol. Sper.43, 1019–1023 (1966) and44, 1784–1787 (1967);45, 860–862 (1969) and45, 863–865 (1969)]. 相似文献
66.
van der Graaf M Janssen SW van Asten JJ Hermus AR Sweep CG Pikkemaat JA Martens GJ Heerschap A 《NMR in biomedicine》2004,17(6):405-410
Localized in vivo 1H magnetic resonance spectroscopy (MRS) was used to investigate metabolite levels in the brain of adult Zucker Diabetic Fatty (ZDF) rats, an animal model for type 2 diabetes mellitus. This study focussed on the hippocampus, assumed to be one of the main brain areas affected by this disease. Together with an almost 5-fold increase in blood glucose concentration measured by glucose oxidation, significant increases were found in the hippocampal concentrations of glucose (4.93 vs 1.66 mM p < 0.001), myo-inositol (6.52 vs 4.30 mM; p < 0.05), and total creatine (12.71 vs 10.50 mM; p < 0.05) in ZDF rats (n = 5) compared with littermates (n = 5). Although no obvious alterations were detected in the hippocampal levels of other metabolites, including NAA + NAAG and choline-containing compounds in the ZDF rats, the increase in Glc and Ins levels is in line with elevated brain tissue contents of these metabolites in patients with diabetes mellitus. 相似文献
67.
Protective efficacy in chickens, geese and ducks of an H5N1-inactivated vaccine developed by reverse genetics 总被引:18,自引:0,他引:18
We generated a high-growth H5N1/PR8 virus by plasmid-based reverse genetics. The virulence associated multiple basic amino acids of the HA gene were removed, and the resulting virus is attenuated for chickens and chicken eggs. A formalin-inactivated oil-emulsion vaccine was prepared from this virus. When SPF chickens were inoculated with 0.3 ml of the vaccine, the hemagglutinin-inhibition (HI) antibody became detectable at 1 week post-vaccination (p.v.) and reached a peak of 10log2 at 6 weeks p.v. then slowly declined to 4log2 at 43 weeks p.v. Challenge studies performed at 2, 3 and 43 weeks p.v. indicated that all of the chickens were completely protected from disease signs and death. Ducks and geese were completely protected from highly pathogenic H5N1 virus challenge 3 weeks p.v. The duration of protective immunity in ducks and geese was investigated by detecting the HI antibody of the field vaccinated birds, and the results indicated that 3 doses of the vaccine inoculation in geese could induce a 34 weeks protection, while 2 doses induced more than 52 weeks protection in ducks. We first reported that an oil-emulsion inactivated vaccine derived from a high-growth H5N1 vaccine induced approximately 10 months of protective immunity in chickens and demonstrated that the oil-emulsion inactivated avian influenza vaccine is immunogenic for geese and ducks. These results provide useful information for the application of vaccines to the control of H5N1 avian influenza in poultry, including chickens and domestic waterfowl. 相似文献
68.
69.
Seventy-eight patients with Burkitt's lymphoma and seventy controls from Ghana were typed for HLA-A, B, C and DR antigens, to determine whether there is an association between the HLA system and Burkitt's lymphoma. Increased relative risk was observed in Burkitt's lymphoma patients with DR7, HLA-A1 and B12 (BW44). 相似文献
70.
Kudryavtseva NN Gerrits MA Alekseenko OV Van Ree JM 《Bulletin of experimental biology and medicine》2005,140(3):320-322
Chronic injections of cocaine (20 mg/kg daily for 10 days) increase activity and decrease anxiety in male C57Bl/6j mice in
comparison with animals chronically injected with normal saline. U-50,488H (κ-opioid receptor agonist; 2.5 mg/kg) produced
an anxiolytic effect in animals preinjected with normal saline and had no effect in animals chronically injected with cocaine.
Presumably, chronic activation of dopaminergic systems caused by cocaine injections is paralleled by desensitization of k-opioid
receptor system.
__________
Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 9, pp. 305–307, September, 2005 相似文献