全文获取类型
收费全文 | 7241篇 |
免费 | 258篇 |
国内免费 | 2256篇 |
出版年
2024年 | 40篇 |
2023年 | 171篇 |
2022年 | 206篇 |
2021年 | 249篇 |
2020年 | 168篇 |
2019年 | 228篇 |
2018年 | 167篇 |
2017年 | 189篇 |
2016年 | 175篇 |
2015年 | 219篇 |
2014年 | 334篇 |
2013年 | 261篇 |
2012年 | 320篇 |
2011年 | 383篇 |
2010年 | 329篇 |
2009年 | 429篇 |
2008年 | 422篇 |
2007年 | 366篇 |
2006年 | 415篇 |
2005年 | 531篇 |
2004年 | 494篇 |
2003年 | 483篇 |
2002年 | 315篇 |
2001年 | 321篇 |
2000年 | 276篇 |
1999年 | 232篇 |
1998年 | 169篇 |
1997年 | 173篇 |
1996年 | 169篇 |
1995年 | 171篇 |
1994年 | 160篇 |
1993年 | 180篇 |
1992年 | 200篇 |
1991年 | 176篇 |
1990年 | 150篇 |
1989年 | 169篇 |
1988年 | 57篇 |
1987年 | 67篇 |
1986年 | 63篇 |
1985年 | 73篇 |
1984年 | 18篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 10篇 |
1980年 | 3篇 |
1978年 | 1篇 |
1966年 | 2篇 |
1963年 | 7篇 |
1956年 | 1篇 |
1953年 | 1篇 |
排序方式: 共有9755条查询结果,搜索用时 109 毫秒
981.
982.
983.
984.
985.
以3个芋品种(‘石川早生’、‘虾籽芋’、‘叶用芋)球茎茎尖为外植体,进行脱病毒和快繁的结果表明,外植体表面灭菌的最佳方法是剥鳞片→乙醇→新洁尔灭→剥幼叶→氯化汞;适宜茎尖分化的培养基为MS+1.0-2.0mg·L^-16-BA+0.2mg·L^-1 NAA。生物学方法和电镜观察显示:连续3代0.5-0.7mm茎尖剥离培养对芋花叶病毒(DMV)的脱毒率达100%。在培养基MS+0.2mg·L^-1 NAA中,适量添加6-BA和TDZ,三品种芋的试管苗增殖效果好;附加KT,试管苗生长健壮且利于生根:添加20-100mg·L^-1的精胺(spm),可促进不定芽的发生,与KT配合使用可促使继代增殖和成苗一步完成。完整植株在草炭土:蛭石=1:1的基质中,移栽成活率超过97%,且苗生长健壮。 相似文献
986.
987.
Liliana Marii Gheorghe Chiriac 《Acta Botanica Sinica》2009,(5):476-488
The effect of virus-host interactions on subsequent generations is poorly understood. The evaluation of the effects of viral infection on inheritance of quantitative traits in the progeny of infected plants and elucidation of a possible relationship between chiasma frequency in the infected plants and variability of traits in the progeny were investigated. The current study involved genotypes of four intraspecific hybrids of tomato (Solanum lycopersicum L.), their parental forms and two additional cultivars. Used as infection were the tobacco mosaic virus (TMV) and potato virus X (PVX). The consequences of the effect of viral infection were evaluated based on chromosome pairing in diakinesis and/or by examining quantitative and qualitative traits in the progeny of the infected tomato plants. Tomato plants infected with TMV + PVX were found to differ in chiasma frequency per pollen mother cell or per bivalent. Deviations have been observed for genotypes of both F1 hybrids and cultivars. At the same time, differences in mean values of the traits under study have only been found for progeny populations (F2-F4) derived from virus-infected F1 hybrids, but not in the case of progeny of the infected cultivars. The rate of recombinants combining traits of both parents increased significantly (2.22-8.24 times) in progeny populations of hybrids infected with TMV+PVX. The above suggests that the observed effects could be the result of modification of recombination frequencies that can be manifested in heterozygous hybrids and make small contributions to variability in cases of 'homozygous' tomato genotypes (i.e. cultivars). 相似文献
988.
989.
Lan-lan ZHANG ;Jin-yu SHEN ;Cheng-feng LEI ;Chao FAN ;Gui-jie HAO ;Qin FANG 《Virologica Sinica》2009,(6):545-551
Grass carp reovirus (GCRV) is a tentative member of the Aquareovirus genus in the family Reoviridae. The mature virion comprises 11 dsRNA genomes enclosed by two concentric icosahedral proteins shells that is comprised of five core proteins and two outer capsid proteins. The genome sequence and 3D structure demonstrate there is a higher level of sequence homology in structural proteins between GCRV and mammalian orthoreoviruses (MRV) compared to other members of the family. To understand the pathogenesis of GCRV infection, the outer capsid protein VP5, a homology of the μ1 protein of MRV, was expressed in E.coli. It was found that the recombinant VP5 was highly expressed, and the expressed His-tag fusion protein was involved in the formation of the inclusion body. Additionally, specific anti-VP5 serum was prepared from purified protein and western blot demonstrated that the expressed protein was able to bind immunologically to rabbit anti GCRV particle serum and the immunogenicity was determined by ELISA assay. Additional experiments in investigating the functional properties of VP5 will further elucidate the role of the GCRV outer capsid protein VP5 during entry into host cells, and its interaction among viral proteins and host cells during the infection process. 相似文献
990.