全文获取类型
收费全文 | 2600409篇 |
免费 | 185033篇 |
国内免费 | 7625篇 |
专业分类
耳鼻咽喉 | 34441篇 |
儿科学 | 85421篇 |
妇产科学 | 71688篇 |
基础医学 | 365149篇 |
口腔科学 | 70036篇 |
临床医学 | 235288篇 |
内科学 | 518504篇 |
皮肤病学 | 62617篇 |
神经病学 | 214474篇 |
特种医学 | 100397篇 |
外国民族医学 | 736篇 |
外科学 | 388568篇 |
综合类 | 50430篇 |
现状与发展 | 5篇 |
一般理论 | 968篇 |
预防医学 | 196588篇 |
眼科学 | 56827篇 |
药学 | 188789篇 |
8篇 | |
中国医学 | 5351篇 |
肿瘤学 | 146782篇 |
出版年
2021年 | 20214篇 |
2019年 | 20778篇 |
2018年 | 29534篇 |
2017年 | 22745篇 |
2016年 | 26428篇 |
2015年 | 29720篇 |
2014年 | 40764篇 |
2013年 | 60794篇 |
2012年 | 80848篇 |
2011年 | 85122篇 |
2010年 | 51417篇 |
2009年 | 49506篇 |
2008年 | 79631篇 |
2007年 | 84444篇 |
2006年 | 86190篇 |
2005年 | 82385篇 |
2004年 | 79363篇 |
2003年 | 76671篇 |
2002年 | 73982篇 |
2001年 | 128774篇 |
2000年 | 131678篇 |
1999年 | 110827篇 |
1998年 | 31435篇 |
1997年 | 28053篇 |
1996年 | 28349篇 |
1995年 | 27490篇 |
1994年 | 25146篇 |
1993年 | 23492篇 |
1992年 | 85390篇 |
1991年 | 81774篇 |
1990年 | 78965篇 |
1989年 | 76275篇 |
1988年 | 69675篇 |
1987年 | 68152篇 |
1986年 | 63717篇 |
1985年 | 60696篇 |
1984年 | 45062篇 |
1983年 | 38023篇 |
1982年 | 22510篇 |
1981年 | 20034篇 |
1979年 | 39047篇 |
1978年 | 27501篇 |
1977年 | 23306篇 |
1976年 | 21543篇 |
1975年 | 22869篇 |
1974年 | 26835篇 |
1973年 | 25409篇 |
1972年 | 23793篇 |
1971年 | 21995篇 |
1970年 | 20228篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Etiological heterogeneity in Hodgkin's disease: HLA linked and unlinked determinants of susceptibility independent of histological concordance 总被引:2,自引:0,他引:2
Forty-one multiplex families, from published sources and new data from the National Cancer Institute, segregating for Hodgkin's disease and HLA, have been studied. A reanalysis of these data strongly suggests a recessive mode of inheritance for susceptibility to Hodgkin's disease. The HLA haplotype sharing data between affected relatives demonstrate that approximately 60% of cases in multiplex families are due to an HLA-linked susceptibility gene, the remaining 40% being due to other familial factors. The data clearly support the hypothesis of etiological heterogeneity for Hodgkin's disease, with both HLA-linked and HLA-unlinked factors being responsible. Finally, there is an increased concordance of histological types between affected relatives, but this concordance seems independent of HLA sharing. 相似文献
992.
993.
Association between PCBs and lower embryonic weight in black-crowned night herons in San Francisco Bay 总被引:3,自引:0,他引:3
D J Hoffman B A Rattner C M Bunck A Krynitsky H M Ohlendorf R W Lowe 《Journal of toxicology and environmental health》1986,19(3):383-391
Reproductive problems, including congenital malformations, reduced hatching success, and decreased survival of hatchlings, have been observed in colonial-nesting water birds at the San Francisco Bay National Wildlife Refuge (SFBNWR). Twenty-four black-crowned night heron (Nycticorax nycticorax) eggs were collected from SFBNWR in 1983. Twelve of these were collected from separate nests when late-stage embryos were pipping, and an additional egg was randomly collected from each nest for organochlorine analysis. Overt anomalies and skeletal defects were not apparent. Embryonic weights (with partially absorbed yolk sacs removed) were 15% lower (p less than 0.05) in SFBNWR embryos compared to control embryos from the Patuxent Wildlife Research Center (PWRC). Crown-rump length and femur length were shorter for SFBNWR embryos. The geometric mean polychlorinated biphenyl (PCB) concentration in SFBNWR eggs was 4.1 ppm wet weight, with a range of 0.8-52.0 ppm. A negative correlation (r = -0.61; p less than 0.05) existed between embryonic weight and log-transformed PCB residues in whole eggs collected from the same nest at SFBNWR, suggesting a possible impact of PCBs on embryonic growth. A correlation with embryonic weight did not occur for DDE [1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene] residues. Liver microsomal aryl hydrocarbon hydroxylase activity was neither significantly elevated nor correlated with PCB, DDE, or PCB plus DDE log-transformed residues. It is unknown whether the apparent association between PCBs and lower weight is persistent through hatching. 相似文献
994.
We report a case of vasoactive-agent-induced priapism successfully treated in the emergency department with 10 mg of metaraminol injected into the corpora cavernosa. 相似文献
995.
996.
Alpha-adrenoreceptor reagents. 4. Resolution of some potent selective prejunctional alpha 2-adrenoreceptor antagonists 总被引:1,自引:0,他引:1
A P Welbourn C B Chapleo A C Lane P L Myers A G Roach C F Smith M R Stillings I F Tulloch 《Journal of medicinal chemistry》1986,29(10):2000-2003
The resolution of three 2-substituted derivatives of idazoxan is described. The enantiomers show large separations in activity in a variety of in vitro and in vivo tests, and the active isomers are all potent and selective antagonists at the alpha 2-adrenoreceptor. The significance of these results in relation to those published on the enantiomers of idazoxan and to those on optically active alpha 2-adrenoreceptor agonists is discussed. 相似文献
997.
Synthesis of Estradiol Haptens Two estradiol haptens, 4-(3β,17β-dihydroxyestran-7α-yl)butanoic acid ( 9 ) and 7α-(4-aminobutyl)-3β,17β-estradiols ( 13 ), were prepared from 19-nortestosterone by partial synthesis. The binding activity for the cytosol estrogen receptor was determined by competition against [3H]-estradiol; at a concentration of 2×10?7mol/l, compound 9 displaces 50% of [3H]-estradiol. Attached to AH-Sepharose 4B compound 9 allows the cytosol estrogen receptor from calf uterus to be concentrated 1800-fold by affinity chromatography. 相似文献
998.
999.
1000.