全文获取类型
收费全文 | 80702篇 |
免费 | 6040篇 |
国内免费 | 209篇 |
出版年
2021年 | 795篇 |
2020年 | 698篇 |
2019年 | 694篇 |
2018年 | 1653篇 |
2017年 | 1471篇 |
2016年 | 2015篇 |
2015年 | 2568篇 |
2014年 | 2759篇 |
2013年 | 3571篇 |
2012年 | 4115篇 |
2011年 | 3885篇 |
2010年 | 2512篇 |
2009年 | 2100篇 |
2008年 | 3160篇 |
2007年 | 3136篇 |
2006年 | 3141篇 |
2005年 | 2621篇 |
2004年 | 2587篇 |
2003年 | 2365篇 |
2002年 | 2268篇 |
2001年 | 3738篇 |
2000年 | 3385篇 |
1999年 | 2523篇 |
1998年 | 893篇 |
1997年 | 716篇 |
1996年 | 674篇 |
1995年 | 608篇 |
1994年 | 543篇 |
1992年 | 1702篇 |
1991年 | 1532篇 |
1990年 | 1444篇 |
1989年 | 1382篇 |
1988年 | 1223篇 |
1987年 | 1217篇 |
1986年 | 1075篇 |
1985年 | 1058篇 |
1984年 | 770篇 |
1983年 | 708篇 |
1979年 | 859篇 |
1978年 | 579篇 |
1977年 | 541篇 |
1975年 | 628篇 |
1974年 | 732篇 |
1973年 | 712篇 |
1972年 | 718篇 |
1971年 | 683篇 |
1970年 | 668篇 |
1969年 | 660篇 |
1968年 | 563篇 |
1966年 | 520篇 |
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
51.
A Sólyom S Tóth I Holczinger J Vajda Z Tóth R Kálmánchey 《Applied neurophysiology》1985,48(1-6):222-225
Four thalamic and cortical recordings were carried out in 5 patients. The thalamic-evoked potentials were typical and revealed a triphasic complex, but their latencies showed a relatively high standard deviation. They could be divided into two groups according to their latencies, both of which had low SD. These data suggested that there could be two types of latency of thalamic SEP, because the 4 patients' body sizes were very similar. More detailed surface, cortical and depth recordings are needed to resolve these questions. 相似文献
52.
53.
54.
55.
Tsyganov V. E.; Pavlova Z. B.; Kravchenko L. V.; Rozov S. M.; Borisov A. Y.; Lutova L. A.; Tikhonovich I. A. 《Annals of botany》2000,86(5):975-981
Using ethyl methane sulfonate (EMS) treatment of the seeds ofline SGE, a new mutant of pea (Pisum sativum L.) with alterationsin root development was obtained. The mutant phenotype dependson the density of the growth substrate: on sand (a high densitysubstrate) the mutant forms a small compact curly root systemwhereas on vermiculite (a low density substrate) differencesbetween the root systems of the mutant and wild type plantsare less pronounced. Genetic analysis revealed that the mutantcarries a mutation in a new pea gene designedcrt (curly roots).Gene crt has been localized in pea linkage group V. The mutantline named SGEcrt showed increased sensitivity to exogenousauxin and an increased concentration of endogenous indole-3-aceticacid (IAA) in comparison with the wild type line SGE. Copyright2000 Annals of Botany Company Pisum sativum L., root development, garden pea mutant, curly roots, auxin, environmental stimulus response 相似文献
56.
Effect of precursors on biosynthesis of monensins A and B 总被引:1,自引:0,他引:1
Precursors of monensins (acetate, propionate, butyrate, isobutyrate) affect the total production and the relative proportion of monensins A and B. Addition of propionate into the fermentation medium causes a prevalence of monensin B whereas butyrate and isobutyrate stimulate the production of monensin A and suppress the production of monensin B. 相似文献
57.
Profile of the alpha-bungarotoxin-binding regions on the extracellular part of the alpha-chain of Torpedo californica acetylcholine receptor. 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《The Biochemical journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The continuous alpha-neurotoxin-binding regions on the extracellular part (residues 1-210) of the alpha-chain of Torpedo californica acetylcholine receptor were localized by reaction of 125I-labelled alpha-bungarotoxin with synthetic overlapping peptides spanning this entire part of the chain. The specificity of the binding was confirmed by inhibition with unlabelled toxin and, for appropriate peptides, with unlabelled anti-(acetylcholine receptor) antibodies. Five toxin-binding regions were localized within residues 1-10, 32-41, 100-115, 122-150 and 182-198. The third, fourth and fifth (and to a lesser extent the first and second) toxin-binding regions overlapped with regions recognized by anti-(acetylcholine receptor) antibodies. The five toxin-binding regions may be distinct sites or, alternatively, different 'faces' in one (or more) sites. 相似文献
58.
M Górska 《Polski tygodnik lekarski (Warsaw, Poland : 1960)》1992,47(46-48):1069-1071
59.
60.
Caitlin M. Cossaboom Laura Córdoba Dianjun Cao Yan-Yan Ni Xiang-Jin Meng 《Journal of virology》2012,86(23):13124-13125
Hepatitis E virus (HEV) is a single-strand positive-sense RNA virus in the family Hepeviridae. The disease caused by HEV, hepatitis E, is an important public health problem in developing countries of Asia and Africa and is also endemic in many industrialized countries, including the United States. HEV has been identified from several other animal species in addition to humans, including the pig, chicken, mongoose, deer, rabbit, ferret, bat, and fish. Here we report the complete genome sequence of the first strain of HEV from rabbits in the United States. Sequence and phylogenetic analyses revealed that the U.S. rabbit HEV is a distant member of the zoonotic genotype 3 HEV, thus raising a concern for potential zoonotic human infection. A unique 90-nucleotide insertion within the X domain of the ORF1 was identified in the rabbit HEV, and this insertion may play a role in the species tropism of HEV. 相似文献