全文获取类型
收费全文 | 370篇 |
免费 | 23篇 |
专业分类
林业 | 20篇 |
农学 | 14篇 |
106篇 | |
综合类 | 36篇 |
农作物 | 26篇 |
水产渔业 | 34篇 |
畜牧兽医 | 124篇 |
园艺 | 2篇 |
植物保护 | 31篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 10篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 11篇 |
2013年 | 12篇 |
2012年 | 32篇 |
2011年 | 37篇 |
2010年 | 16篇 |
2009年 | 15篇 |
2008年 | 18篇 |
2007年 | 19篇 |
2006年 | 15篇 |
2005年 | 20篇 |
2004年 | 12篇 |
2003年 | 11篇 |
2002年 | 8篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 3篇 |
1973年 | 2篇 |
1965年 | 3篇 |
1964年 | 5篇 |
1963年 | 4篇 |
1949年 | 1篇 |
排序方式: 共有393条查询结果,搜索用时 15 毫秒
371.
Effects of breed proportion and components of heterosis for semen traits in a composite cattle breed
下载免费PDF全文
![点击此处可从《Zeitschrift für Tierzüchtung und Züchtungsbiologie》网站下载免费的PDF全文](/ch/ext_images/free.gif)
N. Khayatzadeh G. Mészáros Y. T. Utsunomiya F. Schmitz‐Hsu F. Seefried U. Schnyder M. Ferenčaković J. F. Garcia I. Curik J. Sölkner 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2018,135(1):45-53
The aim of this study was to estimate the non‐additive genetic effects of the dominance component of heterosis as well as epistatic loss on semen traits in admixed Swiss Fleckvieh, a composite of Simmental (SI) and Red Holstein Friesian (RHF) cattle. Heterosis is the additional gain in productivity or fitness of cross‐bred progeny over the mid‐purebred parental populations. Intralocus gene interaction usually has a positive effect, while epistatic loss generally reduces productivity or fitness due to lack of evolutionarily established interactions of genes from different breeds. Genotypic data on 38,205 SNP of 818 admixed, as well as 148 RHF and 213 SI bulls as the parental breeds were used to predict breed origin of alleles. The genomewide locus‐specific breed ancestries of individuals were used to calculate effects of breed difference as well as the dominance component of heterosis, while proxies for two definitions of epistatic loss were derived from 100,000 random pairs of loci. The average Holstein Friesian ancestry in admixed bulls was estimated 0.82. Results of fitting different linear mixed models showed including the dominance component of heterosis considerably improved the model adequacy for three of the four traits. Inclusion of epistatic loss increased the accuracy of the models only for our new definition of the epistatic effect for two traits, while the other definition was so highly correlated with the dominance component that statistical separation was impossible. 相似文献
372.
Background
This study was to determine if feeding laying hens with defatted diatom microalgal biomass (DFA) from biofuel production affected their egg production and health status.Methods
Five replicates of 5 individually caged ISA Babcock White leghorn hens were fed 4 diets, including a corn-soybean meal control diet, a diet containing 7.5% DFA substituting for soybean meal, and diets containing 7.5% or 15% DFA substituting for corn and soybean meal. Body weights, feed intake, feed conversion ratio (FCR), rate of egg production, egg size, egg mass, and several characteristics of eggs were determined at 4 and 8 wk. Venous blood was sampled at 4 and 8 wk for measurement of 5 biomarkers of health.Results
The 15% DFA diet decreased (P <?0.05) feed intake, egg production, and plasma uric acid concentrations as compared with the control diet, but increased (P <?0.05) egg albumen weight and height compared with the 7.5% DFA diets. The two levels of DFA produced dose-dependent (P <?0.05) changes in three color measures of egg yolk, without affecting four hen plasma biochemical indicators of health.Conclusions
Feeding laying hens with 7.5% DFA in the corn-soybean meal diet for 8 wk had no adverse effect on their health, egg production, or egg quality, but 15% inclusion reduced feed intake, egg production, and efficiency of feed utilization. 相似文献373.
Eom CB Cava RJ Fleming RM Phillips JM Vandover RB Marshall JH Hsu JW Krajewski JJ Peck WF 《Science (New York, N.Y.)》1992,258(5089):1766-1769
Single-crystal epitaxial thin films of the isotropic metallic oxides Sr1-xCaxRuO(3) (0 = x = 1) were grown on miscut SrTiO(3)(100) substrates in situ by 90 degrees off-axis sputtering. These thin films exhibit low isotropic resistivities, excellent chemical and thermal stability, good surface smoothness, and high crystalline quality. Furthermore, the lattice parameters and magnetic properties can be varied by simply changing the strontium/calcium ratio. These epitaxial thin films, and their multilayer structures with other oxide materials, can be used for the fabrication of superconducting, ferroelectric, magneto-optic, and electro-optic devices. 相似文献
374.
Shyi-Neng?LouEmail author Hui-Huang?Chen Po-Yang?Hsu Da-Hsuan?Chang 《Fisheries Science》2005,71(4):889-895
ABSTRACT: Changes in purine-related compounds of tilapia surimi product during processing were investigated. The washing step could result in about 60% decrease of total purine content in tilapia mince during processing. The main released purine substance was inosine monophosphate. The major reducing effect was conducted in the first 10 min during washing. No significant changes were observed after washing for 20 and 30 min. The lowest total purine content of tilapia surimi product was obtained with repeating the washing step twice. Thus, this procedure could reduce the purine content of tilapia mince from a high purine content level to a middle level. The gel strength of tilapia surimi product increased with increasing washing duration within 30 min. However, tilapia surimi product with a middle purine content and acceptable gel strength might be produced by washing twice in 10 min during processing. 相似文献
375.
Journal of Pest Science - Organophosphate (OP) insecticides have been an effective control of several tephritid pests. Recently, OP resistance has been observed in various fly species from... 相似文献
376.
Wen-Liang Lai Lih-Fu Chen Shao-Wei Liao Shu-Lin Hsu Li-Ho Tseng Chang-Ling Miaw 《Water, air, and soil pollution》2007,186(1-4):43-53
This study conducted a two-stage experiment. The first stage attempted to establish biostable filter beds. Two parameters, total bacterial count (TBC) and non-purgeable dissolved carbon (NPDOC), measured by passing through a 0.2 μm membrane filter, were selected to compare the difference of biostability of a filtration system with recirculation with different O3-to-NPDOC ratios of filtered water. The excitation emission fluorescence matrix (EEFM) was used as an effective tool for understanding information regarding organic characteristics by comparing source filtered water before and after ozonation and the effluent during biostablizing filter. During the second stage, a biostable filter was used to compare differences in biodegradability of ozonated products sodium oxalate and sodium acetate. Experimental results demonstrate that both parameters, NPDOC removal and TBC, can be utilized to evaluate the biostabilty of a filter bed. With each parameter, a plateau was reached in roughly 20 days. The source water from Chen Ching Lake (CCL) contained a protein-like substance determined by the EEFM. This protein-like substance was also destroyed by O3/NPDOC?=?1.1. Soluble microbial products (SMPs) released from the biostablizing filter into the effluent have two peaks in the EEFM, identified as protein-like and humic-like acid. The NPDOC removal for the biostabilizing filter using O3/NPDOC?=?1.7 was less than that using O3/NPDOC?=?1.1. Bacterial counts in the effluent from the biostabilizing filter using O3/NPDOC?=?1.1 was better than that of O3/NPDOC?=?1.7. This difference can be explained by the high ratio of O3/NPDOC producing by-products of ozonation that were easily utilized by microorganisms; however, filter bed also released relatively more SMPs owing to increased proliferation of microorganisms attached to glass pellets in the filter. Regarding the differences in decomposition of the by-products of ozonation by the biostable filter, such as sodium oxalate, the NPDOC removal at O3/NPDOC?=?1.1 was better than that at O3/DOC?=?1.7. This phenomenon can be explained as previously mentioned. 相似文献
377.
Chen JJ Chen GH Hsu HC Li SS Chen CS 《Journal of agricultural and food chemistry》2004,52(8):2256-2261
It was shown previously that a bacterially expressed mungbean defensin VrCRP exhibited both antifungal and insecticidal activities. To isolate this protein in a large quantity for its characterization, the defensin cDNA was expressed in Pichia pastoris and the recombinant defensin (rVrD1) was purified. The recombinant VrD1 was shown to inhibit the growth of fungi such as Fusarium oxysporum, Pyricularia oryza, Rhizoctonia solani, and Trichophyton rubrum and development of bruchid larva. The protein also inhibits in vitro protein synthesis. These biological activities are similar to that of the bacterially expressed defensin. Functional expression of VrD1 in Pichia pastoris provides a highly feasible system to study the structure-function relationship of VrD1 using the mutagenesis approach. 相似文献
378.
温度对微晶氧化铁形成与性质的影响 总被引:2,自引:0,他引:2
稀释0.5mol/L Fe(NO3)3母液,制成二组0.001mol/L Fe(NO3)3,溶液,每组分成5等份,于每份溶液中分别加入不同量的NaOH,使溶液的NaOH/Fe,分子比为0、1.0、1.8、2.7、3.1,然后在70℃烘箱中水解。制备二组试样的主要区别是母液稀释水的最初温度不同,但其最终形成的氧化铁在颗粒大小,结晶度以及显微形貌等方面有明显差别。Ⅰ组试样是用70℃水稀释制备而成,1天后其反应产物呈无定形的非晶物质,在70℃老化很短时间后,便转变成结晶好的针铁矿和赤铁矿。Ⅱ组试样是用室温水(25℃)制备。在整个实验期间,其水解产物具有轮廓明显的小圆球状微晶氧化铁,即使在老化248天后仍属结晶差的针铁矿和赤铁矿,只能用高功率转靶的X射线衍射仪才能反映其特征衍射峰,鉴定其组成。试验结果表明:制备试样时,水的温度对最初水解产物的性质起关键作用,而最初产物的特性对溶液中再溶解再结晶的速率起着重要作用。 相似文献
379.
Hsu PC Huang YT Tsai ML Wang YJ Lin JK Pan MH 《Journal of agricultural and food chemistry》2004,52(20):6330-6337
Shikonin is a main constituent of the roots of Lithospermum erythrorhizon that has antimutagenic activity. However, its other biological activities are not well-known. Shikonin displayed a strong inhibitory effect against human colorectal carcinoma COLO 205 cells and human leukemia HL-60 cells, with estimated IC(50) values of 3.12 and 5.5 microM, respectively, but were less effective against human colorectal carcinoma HT-29 cells, with an estimated IC(50) value of 14.8 microM. Induce apoptosis was confirmed in COLO 205 cells by DNA fragmentation and the appearance of a sub-G1 DNA peak, which were preceded by loss of mitochondrial membrane potential, reactive oxygen species (ROS) generation, cytochrome c release, and subsequent induction of pro-caspase-9 and -3 processing. Cleavages of poly(ADP-ribose) polymerase (PARP) and DNA fragmentation factor (DFF-45) were accompanied by activation of caspase-9 and -3 triggered by shikonin in COLO 205 cells. Here, we found that shikonin-induced apoptotic cell death was accompanied by upregulation of p27, p53, and Bad and down-regulation of Bcl-2 and Bcl-X(L), while shikonin had little effect on the levels of Bax protein. Taken together, we suggested that shikonin-induced apoptosis is triggered by the release of cytochrome c into cytosol, procaspase-9 processing, activation of caspase-3, degradation of PARP, and DNA fragmentation caused by the caspase-activated deoxyribonuclease through the digestion of DFF-45. The induction of apoptosis by shikonin may provide a pivotal mechanism for its cancer chemopreventive action. 相似文献
380.
Dinsmore AD Hsu MF Nikolaides MG Marquez M Bausch AR Weitz DA 《Science (New York, N.Y.)》2002,298(5595):1006-1009
We present an approach to fabricate solid capsules with precise control of size, permeability, mechanical strength, and compatibility. The capsules are fabricated by the self-assembly of colloidal particles onto the interface of emulsion droplets. After the particles are locked together to form elastic shells, the emulsion droplets are transferred to a fresh continuous-phase fluid that is the same as that inside the droplets. The resultant structures, which we call "colloidosomes," are hollow, elastic shells whose permeability and elasticity can be precisely controlled. The generality and robustness of these structures and their potential for cellular immunoisolation are demonstrated by the use of a variety of solvents, particles, and contents. 相似文献