全文获取类型
收费全文 | 89篇 |
免费 | 11篇 |
专业分类
100篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 1篇 |
2012年 | 3篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 6篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1989年 | 3篇 |
1987年 | 1篇 |
1985年 | 4篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1977年 | 2篇 |
1972年 | 2篇 |
1961年 | 1篇 |
1950年 | 1篇 |
1925年 | 1篇 |
1915年 | 1篇 |
排序方式: 共有100条查询结果,搜索用时 0 毫秒
11.
12.
Quantifying the transfer of Escherichia coli O157 from the environment to humans is essential for understanding outbreaks, establishing the infectious dose of the organism and proposing safeguards. We modelled the pathogen loading shed onto a field by sheep immediately prior to a scout camp where 18 scouts and two adults were infected with E. coli O157. We estimated the dose ingested (4-24 organisms) which is in agreement with the low infective dose reported previously for this organism in food outbreaks. These data closely fit a surrogate Shigella dose-response model which can be used as a basis for risk assessment. 相似文献
13.
T. WORTHINGTON P. S. KEMP P. E. OSBORNE A. DILLEN J. COECK M. BUNZEL‐DRÜKE M. NAURA J. GREGORY K. EASTON 《Freshwater Biology》2012,57(3):602-611
1. Availability of suitable habitat is a prerequisite for species reintroduction success, and to ensure population persistence, investigations of a species’ habitat utilisation throughout its life history should be conducted as part of a feasibility study. 2. Habitat utilisation models for burbot, Lota lota, developed using data from field studies conducted in France and Germany and information from the literature were used to assess the feasibility of reintroducing burbot into rivers of its former native range in eastern England. 3. Per cent tree roots, aquatic vegetation and flow types were important predictors of adult burbot abundance. Furthermore, the habitat utilisation models were supplemented with information from the literature, which suggested that off‐channel habitat such as wetlands and backwaters is important for spawning and nursery stages. 4. An assessment of the habitat availability in the rivers of the burbot’s former native range using variables related to spawning and nursery and adult life stages showed that although adult habitat was widely distributed, the availability of spawning and nursery habitat was less abundant, potentially limiting successful reestablishment. 5. Potential suitable habitat was concentrated in the central and southern areas of the species’ former English distribution. Overall, rivers of the burbot’s former range potentially afford suitable habitat to sustain a reintroduced population. However, sites should be preferentially selected on the basis of having appropriate spawning and nursery areas. 相似文献
14.
Christine A. Black Jason W. Ucci Jeremy S. Vorpagel Matthew C. Mauck Edward E. Fenlon 《Bioorganic & medicinal chemistry letters》2002,12(24)
A stereoselective synthesis of 3′-O-((R,R,R)-trimethylsilatranyl)thymidine (R,R,R-1) and synthesis of 3′-O-silatranylthymidine (5) via an improved silatranylation procedure using tetrakis(dimethylamino)silane are reported. Diastereomeric mixture 1 showed more activity than R,R,R-1 or 5 in a primary anticancer screen against breast, CNS, and lung cell lines; demonstrating the import of the configuration and presence, respectively, of the silatrane methyl groups for growth inhibition. 相似文献
15.
Hussan Bin Abdul Kadir Christopher C. Payne Norman E. Crook John S. Fenlon Doreen Winstanley 《Biocontrol Science and Technology》1999,9(3):421-433
The susceptibility of larvae of the Diamondback moth (DBM), Plutella xylostella to infection by three baculoviruses was evaluated in the laboratory using a microdroplet feeding assay. The viruses tested were a granulovirus (GV), originally isolated in Taiwan from P. xylostella larvae (Px GV-Taiwan); the nucleopolyhedrovirus (NPV) from Galleria mellonella (Gm NPV), and the NPV from Autographa californica (Ac NPV). Neonate P. xylostella larvae were susceptible to infection by all three viruses. In an extensive series of bioassays carried out over a 21-month period, LD 50S for neonate DBM larvae ranged from 1.0-8.9 viral occlusion bodies (OB) for Px GV-Taiwan, and 9.5-30.2 OB for Gm NPV and Ac NPV. LT 50S for the three viruses ranged from 3.8-6.0 days at 27 C, with Gm NPV having a significantly shorter LT 50 than the other two viruses. Second and third instar larvae of P. xylostella were significantly less susceptible to infection by Px GV-Taiwan (LD 50 s ranging from 18-57 OB/larva) than were neonate larvae. Gm NPV also initiated infection in several other lepidopterous pest species that colonize brassica crops. In particular, neonate Crocidolomia binotalis larvae proved highly susceptible to Gm NPV, with mean LD 50 s ranging from 2.1 to 9.3 OB/larva and a mean LT 50 of 4.8 days at a dose of 8.08 OB. Heliothis virescens neonate larvae were also highly susceptible to Gm NPV (LD 50 , 7.1 OB), but Mamestra brassicae larvae were less so (LD 50 , 80-270 OB). The results of the bioassays suggest that Px GV-Taiwan is highly infective and could be developed as a selective microbial pesticide for DBM. While Gm NPV has a higher LD 50 in DBM larvae, its wider host range may be of considerable value in situations where DBM occurs on cruciferous crops together with a complex of other lepidopterous pests. 相似文献
16.
17.
18.
19.
20.
Goring DR Banks P Fallis L Baszczynski CL Beversdorf WD Rothstein SJ 《The Plant journal : for cell and molecular biology》1992,2(6):999-1003
We have previously described a developmentally regulated mRNA in maize that accumulates in mature embryos and is involved in a variety of stress responses in the plant. The sequence of the encoded 16 kDa protein (MA16) predicts that it is an RNA-binding protein, since it possesses a ribonucleoprotein consensus sequence-type RNA-binding domain (CS-RBD). To assess the predicted RNA binding property of the protein and as a starting point to characterize its function we have used ribohomopolymer-binding assays. Here we show that the MA16-encoded protein binds preferentially to uridine- and guanosine-rich RNAs. In light of these results a likely role for this protein in RNA metabolism during late embryogenesis and in the stress response is discussed. 相似文献