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排序方式: 共有69条查询结果,搜索用时 15 毫秒
1.
KM Morton SL Catt FK Hollinshead WMC Maxwell G Evans 《Reproduction in domestic animals》2004,39(6):454-461
Cumulus-oocyte complexes from hormone-stimulated 3-4-week-old (n=43) and 6-7-week-old (n=12) prepubertal lambs were matured in vitro and incubated with unsorted, or X- or Y-spermatozoa separated with a high-speed cell sorter (SX MoFlo)frozen-thawed. Presumptive zygotes were then cultured to the blastocyst stage, and transferred to recipients fresh or after cryopreservation (frozen). Oocyte cleavage was higher (p <0.05) with unsorted (515/926, 55.6%) than X- or Y-spermatozoa (261/672, 38.8% and 229/651, 35.2%, respectively) and blastocyst formation (% zygotes) by Day 9 of in vitro culture was lower (p <0.05) for X- (102/261, 39.1%) than unsorted spermatozoa (249/515, 48.3%), but did not differ between Y-spermatozoa (103/229, 45.0%) and unsorted spermatozoa, or between X- and Y-spermatozoa (p >0.05). For fresh embryos, survival to term was 50.0% (3/6) for unsorted, 0.0% (0/6) for X- and 16.7% (1/6) for Y-spermatozoa-derived embryos (p >0.05), and for frozen embryos was 4.0% (2/50) for unsorted, 9.1% (2/22) for X- and 2.9% (1/34) Y-spermatozoa-derived embryos (p >0.05). Of the two lambs born from X-spermatozoa-derived embryos, one was female (50%), and from the two Y-spermatozoa-derived lambs, both were male (100%), demonstrating that lambs can be produced after the transfer of fresh and cryopreserved IVP embryos derived from prepubertal lamb oocytes and frozen-thawed sex-sorted sperm. 相似文献
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3.
The dairy-cow results are presented from an experiment in which the response to grass irrigation was measured at two stocking rates. The method and herbage results have already been described (1).
Over two years, with an average application rate of 5·5 in of water per year, the main effect of irrigation was to increase the number of grazing days obtained by 35%. Neither yield per cow nor milk quality was significantly affected by the treatments.
The data emphasize the importance of high stocking rates for the full exploitation of irrigation. The practical implications of the results are discussed; they suggest that in the right circumstances of herd potential and grassland management, irrigation for milk production can be highly profitable. 相似文献
Over two years, with an average application rate of 5·5 in of water per year, the main effect of irrigation was to increase the number of grazing days obtained by 35%. Neither yield per cow nor milk quality was significantly affected by the treatments.
The data emphasize the importance of high stocking rates for the full exploitation of irrigation. The practical implications of the results are discussed; they suggest that in the right circumstances of herd potential and grassland management, irrigation for milk production can be highly profitable. 相似文献
4.
Andrew S. Brierley Paul G. Fernandes Mark A. Brandon Frederick Armstrong Nicholas W. Millard Steven D. McPhail Peter Stevenson Miles Pebody James Perrett Mark Squires Douglas G. Bone Gwyn Griffiths 《Fisheries Research》2003,60(2-3):569-576
The autonomous underwater vehicle (AUV) Autosub-2 was deployed on eight missions ahead of RRS James Clark Ross in the northern Weddell Sea and in the Bransfield Strait, Southern Ocean, to assess avoidance of the research vessel by Antarctic krill Euphausia superba. The AUV was equipped with the same type of scientific echosounder as the research vessel (Simrad EK500 operating at 38 and 120 kHz) and measured the density of krill along transect acoustically (g m−2 wet mass) prior to the ship’s arrival. We hypothesised that if krill avoided the ship, perhaps in response to radiated noise, then the ship should detect less krill than the AUV which is known to have much lower noise levels than the ship. We were unable to detect any significant difference between the density of krill detected by the ship or the AUV, either at the transect level or at finer scales within transects. We conclude, therefore, that avoidance by krill of RRS James Clark Ross will not significantly bias acoustic estimates of krill abundance by this vessel. 相似文献
5.
KM Blackwood 《Science (New York, N.Y.)》1996,273(5277):909-912
Side-chain ferroelectric liquid crystalline polymers are currently used in a number of applications, including displays and electrical sensors. Comparisons with existing technologies and materials indicate that relative to ceramics, such polymers have lower figures of merit but offer greater durability in sensor applications. 相似文献
6.
D L Bone 《Veterinary Clinics of North America: Small Animal Practice》1987,17(4):923-942
Chronic joint luxations may result from either traumatic injuries or congenital defects. Traumatic luxations are the most common and most amenable to surgical correction. Several surgical techniques for repair of hip, shoulder, and elbow luxations will be presented in this article. 相似文献
7.
Ozan Avinc Huw Owens John Bone Mike Wilding Duncan Phillips David Farrington 《Fibers and Polymers》2011,12(7):893-903
Water droplets falling onto finished fabrics can create spots which can spoil the appearance of the fabric. This study compares
the propensity of softened filament polylactic acid and polyester fabrics to exhibit the adverse affects of ‘water-spotting’,
and to identify suitable softeners and methods for their application to minimise and eliminate the problem. The degree of
water spotting was greater on softened polylactic acid fabrics than on softened polyester fabrics. Polylactic acid and polyester
fabrics with hydrophobic properties did not exhibit any water spotting. Softeners applied by an exhaustion process resulted
in a finished fabric which exhibited no water spotting for either dyed polylactic acid or dyed polyester fabrics. The softening
active agent was not responsible for the water spotting. The other components in the softener formulation (such as emulsifier,
wetting agent), which carries the unfixed dyes with water, were found to be responsible. The water spot halo disappeared after
a single machine laundering process. 相似文献
8.
AK Biswas Pankaj Sharma KM Hati S Ramana AB Singh 《Communications in Soil Science and Plant Analysis》2018,49(17):2189-2196
Distilleries produce a huge quantity of effluents, popularly known as spent wash (SW), which when bio-methanated produce post-methanation effluents (PME). A field experiment on soybean–wheat system was conducted for five consecutive years in a Vertisol of central India to evaluate the effect of distillery effluent (DE) on soil carbon and nitrogen dynamics. Ten treatment combinations consisting of control, 100% NPK + Farmyard Manure (FYM), and graded level of SW and PME were applied. Total carbon content of soil increased significantly with applications of FYM and DE. SW was found superior in enhancing carbon content of soil in comparison to PME. Farmyard Manure contributed more carbon toward the recalcitrant pool, whereas DE contributed more carbon toward the active and slow pool. Nitrogen (N) availability was significantly improved with the application of DE. Balanced application of DE may act as amendment for increasing C and N stocks in Vertisol. 相似文献
9.
J. Bone D. Barraclough P. Eggleton M. Head D. T. Jones N. Voulvoulis 《Land Degradation \u0026amp; Development》2014,25(3):251-266
Emergence of policies dealing with concern over soil degradation and anthropogenic impacts to soil is likely to increase the requirement for assessment of soil quality and identification of soils at risk from degradation. An example is the proposed EU Soil Framework Directive, which features the identification of areas requiring protection from soil degradation. There have been some serious objections to such requirements on the grounds of resource and capital demands. To help to address these concerns, this work proposes a strategic set of indicators based on measured soil quality indicators. These can be used in screening locations to assess the likelihood of degradation and indicate areas for further detailed assessment. This will allow further emphasis to be placed on a smaller number of locations, which could lead to cost and resource efficiencies. Indicators have been used in the past in assessment of soil quality; they are parameters which can be measured and correspond to assessment criteria to measure and help monitor the status and changes. The study reviews the current state of soil quality assessment including methods and indicators that are used to collect data and approaches used to assess data to determine areas subject to soil degradation. Methods and practicalities for data collection and screening are discussed, including the need for further pilot testing and protocol development. Use of public data collection could allow more resource efficient protection of soils, in addition to benefits of public engagement, and raising awareness of the importance of soils and soil biodiversity. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
10.
The effects of Echinacea and several of its phytochemical components on NFkappaB expression by Jurkat cells (a human T-cell line) were investigated in vitro. In the absence of stimulation, Echinacea and its components exerted no significant effect on basal NFkappaB expression levels. In the presence of endotoxin (LPS), NFkappaB expression was decreased. However, this decrease was significantly reversed by treatment with cichoric acid, an Echinacea root extract (prepared from both Echinacea angustifolia and Echinacea purpurea) and the alkylamide fraction derived from this combination. For the phorbol myristate acetate stimulation of Jurkat cells, effects on NFkappaB expression were mixed. Depending on the concentration, cichoric acid and a 2,4-diene alkylamide significantly induced NFkappaB levels, whereas a 2-ene alkylamide caused a significant inhibition. In contrast, both the Echinacea and the mixed alkylamide fraction exerted no effect. The alkylamide results indicate that the two basic forms of these compounds present in Echinacea may have opposing effects. These opposing effects demonstrate the importance of a knowledge, not only of the phytochemical make-up of a herbal preparation, but also of the actions of each component and the consequences of differing relative amounts in the preparation being investigated. 相似文献