全文获取类型
收费全文 | 906篇 |
免费 | 71篇 |
出版年
2023年 | 5篇 |
2022年 | 14篇 |
2021年 | 34篇 |
2020年 | 24篇 |
2019年 | 22篇 |
2018年 | 37篇 |
2017年 | 31篇 |
2016年 | 61篇 |
2015年 | 54篇 |
2014年 | 69篇 |
2013年 | 60篇 |
2012年 | 72篇 |
2011年 | 71篇 |
2010年 | 34篇 |
2009年 | 29篇 |
2008年 | 56篇 |
2007年 | 46篇 |
2006年 | 30篇 |
2005年 | 38篇 |
2004年 | 30篇 |
2003年 | 26篇 |
2002年 | 31篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 13篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有977条查询结果,搜索用时 15 毫秒
971.
Amanda Reges de Sena Flávio Manoel Barros Oliveira Tonny Cley Campos Leite Talita Camila Evaristo da Silva Nascimento Keila Aparecida Moreira 《Preparative biochemistry & biotechnology》2017,47(9):945-951
The aims of the current study are to assess the influence of polyethylene glycol (PEG) concentration, molar mass, pH, and citrate concentrations on aqueous biphasic systems based on 24 factorial designs, as well as to check their capacity to purify tannase secreted by Aspergillus tamarii URM 7115. Tannase was produced through submerged fermentation at 26°C for 67?h in Czapeck-Dox modified broth and added with yeast extract and tannic acid. The factorial design was followed to assess the influence of PEG molar mass (MPEG 600; 4,000 and 8,000?g/?mol), and PEG (CPEG 20.0; 22.0 and 24.0% w/w) and citrate concentrations (CCIT 15.0, 17.5, and 20.0%, w/w), as well as of pH (6.0, 7.0, and 8.0) on the response variables; moreover, partition coefficient (K), yield (Y), and purification factor (PF) were analyzed. The most suitable parameters to purify tannase secreted by A. tamarii URM 7115 through a biphasic system were 600 (g/mol) MPEG, 24% (w/w) CPEG, 15% (w/w) CCIT at pH 6.0 and they resulted in 6.33 enzyme partition, 131.25% yield, 19.80 purification factor and 195.08 selectivity. Tannase secreted by A. tamarii URM 7115 purified through aqueous biphasic systems composed of PEG/citrate can be used for industrial purposes, since it presents suitable purification factor and yield. 相似文献
972.
This study explores the basis for conservation action on Astronium fraxinifolium Schott (Anacardiaceae). This is a wide-ranging forest species occurring in Brazil and other South American countries, and typical of gallery forest along watercourses in the Cerrado region. Information about this species is scanty and scattered. This paper aims to provide a structured review of available knowledge of its biology, ecology, silviculture and management. Widely-scattered published reports have been critically considered and efforts made to highlight and resolve contradictions and inconsistencies. Because little effort has been applied to its domestication and improvement, knowledge of silviculture and management of Astronium fraxinifolium is particularly meagre. Gaps in current knowledge relevant for conservation are identified and steps to fill them proposed. Where in situ conservation was considered appropriate, recommendations are made for the location of additional protected areas. Complementary ex situ and enrichment conservation action is suggested for specific parts of the range where resource losses are already so extensive that in situ measures alone are insufficient. Provision for refining the limited management and conservation knowledge is made through highlighting priorities for study of the taxon. Finally, future action is discussed in the context of the infrastructure of the national conservation sector of Brazil. 相似文献
973.
Emygdio Ana Paula Mendes Degobbi Cristiane Carotenuto Federico Castro e Silva Dulcilena de Matos Quintino Thaysla Beluco Zanetti Rafael Henrique de Souza Mantoani Mauricio C. Boschilia Solana Meneghel Guerra Lara Chaves Carvalho da Silva Dias Pedro Leite Morris Cindy E. Gonalves Fbio Luiz Teixeira 《Aerobiologia》2022,38(1):85-101
Aerobiologia - Primary biological aerosol particles (PBAPs) are involved in multiple phenomena ranging from seasonal allergies to pandemic diseases. Furthermore, PBAPs that act as ice nuclei, might... 相似文献
974.
975.
Gustavo H Esteves Ana CQ Simoes Estevao Souza Rodrigo A Dias Raydonal Ospina Thiago M Venancio 《BMC systems biology》2007,1(1):38-9
Background
Smallpox is a lethal disease that was endemic in many parts of the world until eradicated by massive immunization. Due to its lethality, there are serious concerns about its use as a bioweapon. Here we analyze publicly available microarray data to further understand survival of smallpox infected macaques, using systems biology approaches. Our goal is to improve the knowledge about the progression of this disease. 相似文献976.
977.