全文获取类型
收费全文 | 152篇 |
免费 | 14篇 |
专业分类
林业 | 7篇 |
2篇 | |
综合类 | 9篇 |
畜牧兽医 | 125篇 |
园艺 | 1篇 |
植物保护 | 22篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2020年 | 1篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 5篇 |
2012年 | 9篇 |
2011年 | 6篇 |
2010年 | 10篇 |
2009年 | 5篇 |
2008年 | 8篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 8篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 2篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1938年 | 1篇 |
排序方式: 共有166条查询结果,搜索用时 15 毫秒
1.
2.
Epizootiology of listeric infection in sheep 总被引:1,自引:0,他引:1
A H Killinger M E Mansfield 《Journal of the American Veterinary Medical Association》1970,157(10):1318-1324
3.
4.
5.
Blaise Ratcliffe Foster J. Hart Jaroslav Klápště Barry Jaquish Shawn D. Mansfield Yousry A. El-Kassaby 《Annals of Forest Science》2014,71(3):415-424
Context
Wood quality traits are important to balance the negative decline of wood quality associated with selection for growth attributes in gymnosperm breeding programs. Obtaining wood quality estimates quickly is crucial for successful incorporation in breeding programs.Aims
The aims of this paper are to: (1) Estimate genetic and phenotypic correlations between growth and wood quality attributes, (2) Estimate heritability of the studied traits, and (3) Assess the accuracy of in situ non-destructive tools as a representative of actual wood density.Methods
Wood density (X-ray densitometry), tree height, diameter, volume, resistance drilling, acoustic velocity, and dynamic modulus of elasticity were estimated, along with their genetic parameters, for 1,200, 20-year-old trees from 25 open-pollinated families.Results
Individual tree level heritabilities for non-destructive evaluation attributes were moderate ( $ {\widehat{h}}_i^2=0.37-0.42 $ ), wood density and growth traits were lower ( $ {\widehat{h}}_i^2=0.23-0.35 $ ). Favorable genetic and phenotypic correlations between growth traits, wood density, and non-destructive evaluation traits were observed. A perfect genetic correlation was found between resistance drilling and wood density (r G ?=?1.00?±?0.07), while acoustic velocity and dynamic modulus of elasticity showed weaker genetic correlations with wood density (r G ?=?0.25?±?0.24;?0.46?±?0.21, respectively).Conclusion
This study confirmed that resistance drilling is a reliable predictor of wood density in western larch, while the weak genetic correlations displayed by acoustic velocity and dynamic modulus of elasticity suggest limited dependability for their use as fast in situ wood density assessment methods in this species. 相似文献6.
7.
Nicola K Richards Sarah Mansfield Richard J Townsend Colin M Ferguson 《Pest management science》2017,73(11):i-i
The cover image, by Nicola K Richards et al., is based on the Research Article Genetic variation within species and haplotypes of the Wiseana (Lepidoptera: Hepialidae) complex and development of non‐sequenced based identification tools to aid field studies, DOI: 10.1002/ps.4620 . Photo Credit: Colin M. Ferguson, AgResearch‐ Invermay.
8.
Mansfield E 《Science (New York, N.Y.)》1980,209(4461):1091-1093
R & D, through its effects on the rate of productivity increase, can significantly restrain the rate of inflation in the medium and long run. High rates of inflation damage the workings of the price system and impair the efficiency of practically all economic activities, including R & D. Findings suggest that the percentage increase between 1969 and 1979, in total real R & D expenditures, has been exaggerated due to the inadequacy of the gross national product deflator as applied to R & D. 相似文献
9.
Progress has recently been made in implementing magnetic resonance imaging (MRI) techniques that can be used to obtain images in a fraction of a second rather than in minutes. Echo-planar imaging (EPI) uses only one nuclear spin excitation per image and lends itself to a variety of critical medical and scientific applications. Among these are evaluation of cardiac function in real time, mapping of water diffusion and temperature in tissue, mapping of organ blood pool and perfusion, functional imaging of the central nervous system, depiction of blood and cerebrospinal fluid flow dynamics, and movie imaging of the mobile fetus in utero. Through shortened patient examination times, higher patient throughput, and lower cost per MRI examination, EPI may become a powerful tool for early diagnosis of some common and potentially treatable diseases such as ischemic heart disease, stroke, and cancer. 相似文献
10.
Significant increases in pulping efficiency in C4H-F5H-transformed poplars: improved chemical savings and reduced environmental toxins 总被引:14,自引:0,他引:14
Huntley SK Ellis D Gilbert M Chapple C Mansfield SD 《Journal of agricultural and food chemistry》2003,51(21):6178-6183
The gene encoding ferulate 5-hydroxylase (F5H) was overexpressed in poplar (Populus tremula x Populus alba) using the cinnamate-4-hydroxylase (C4H) promoter to drive expression specifically in cells involved in the lignin biosynthetic pathway and was shown to significantly alter the mole percentage of syringyl subunits in the lignin, as determined by thioacidolysis. Analysis of poplar transformed with a C4H-F5H construct demonstrated significant increases in chemical (kraft) pulping efficiency from greenhouse-grown trees. Compared to wild-type wood, decreases of 23 kappa units and increases of >20 ISO brightness units were observed in trees exhibiting high syringyl monomer concentrations. These changes were associated with no significant modification in total lignin content and no observed phenotypic differences. C4H-F5H-transformed trees could increase pulp throughputs at mills by >60% while concurrently decreasing chemicals employed during processing (chemical pulping and bleaching) and, consequently, the amount of deleterious byproducts released into the environment. 相似文献