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51.
Seedbed preparation can involve a wide range of tillage methods from intensive to reduced cultivation systems. The state or quality of the soil to which these tillage methods are applied for cereal crop management is not easily determined and excessive cultivations are often used. Seedbed preparation is crucial for crop establishment, growth and ultimately yield. A key aspect of the soil condition is the soil physical environment under which germination, growth and establishment occur. Crucially this affects factors such as temperature, water content, oxygen availability, soil strength and ultimately the performance of a seedbed. The dynamics of soil physical properties of a range of seedbeds and how they relate to crop establishment are considered in this paper. Significant interactions between cultivation techniques, physical properties of the seedbed in terms of penetration resistance, shear strength, volumetric water content and bulk density and the interaction with crop establishment were identified. A soil quality of establishment (SQE) model was developed for the prediction of crop establishment based upon soil bulk density and cultivation practices. The SQE significantly accounted for ca. 50% of the variation occurring and successfully predicted crop establishment to a standard error of around 20 plants per m−2 across contrasting soil types and environmental conditions. 相似文献
52.
Sponheimer M Passey BH de Ruiter DJ Guatelli-Steinberg D Cerling TE Lee-Thorp JA 《Science (New York, N.Y.)》2006,314(5801):980-982
Traditional methods of dietary reconstruction do not allow the investigation of dietary variability within the lifetimes of individual hominins. However, laser ablation stable isotope analysis reveals that the delta13C values of Paranthropus robustus individuals often changed seasonally and interannually. These data suggest that Paranthropus was not a dietary specialist and that by about 1.8 million years ago, savanna-based foods such as grasses or sedges or animals eating these foods made up an important but highly variable part of its diet. 相似文献
53.
Paul D. McGreevy Melissa Starling N.J. Branson Mia L. Cobb Debbie Calnon 《Journal of Veterinary Behavior: Clinical Applications and Research》2012,7(2):103-117
This article reviews the literature on the complex and variable nature of the dog–human dyad and describes the influence of terms such as “dominance” on attitudes that humans have toward dogs. It highlights a legacy of tension between ethology and psychology and notes that some practitioners have skills with dogs that elude the best learning theorists. Despite the widespread appeal of being able to communicate with dogs as dogs do with one another, attempting to apply the intraspecific dog ethogram to human–dog and dog–human interactions may have limited scope. The balance of learning theory and ethology on our interactions with dogs is sometimes elusive but should spur the scientific community to examine skills deployed by the most effective humane practitioners. This process will demystify the so-called whispering techniques and permit discourse on the reasons some training and handling techniques are more effective, relevant, and humane than others. This article explores the mismatch between the use of nonverbal communication of 2 species and offers a framework for future studies in this domain. Technologies emerging from equitation science may help to disclose confusing interventions through the collar and lead and thus define effective and humane use of negative reinforcement. The case for a validated intraspecific and interspecific canid ethogram is also made. 相似文献
54.
Sanders RA Hogan DE Green HW Hoyer MH Puppel DA 《Journal of the American Veterinary Medical Association》2005,227(3):430-434
Atrial septal defect, while rare in dogs, can result in severe clinical signs. Surgical correction of atrial septal defect requires open-heart surgery. Transcatheter closure techniques provide minimally invasive surgical alternatives. 相似文献
55.
56.
Many regions of South Africa are prone to woody plant thickening. This can have an ecologically detrimental effect on the open savannas and grasslands. KwaZulu-Natal, a province on the east coast of South Africa, is currently experiencing an increase in both the density and distribution of Vachellia nilotica. This research aims to gain better insight into the potential distribution of this plant and to determine some of the main environmental conditions that promote its thickening. Using the Maxent programme to determine the potential distribution, a map was developed to illustrate the possible extent of V. nilotica within KwaZulu-Natal. It is estimated that a possible 800 968 ha (8.5%) of the province has a greater than 50% distribution probability, whereas in 26.9% of the province there is 25%–50% probability of V. nilotica inhabiting these areas. Using Maxent, it was determined that geology and altitude were key determinants for V. nilotica habitat selection. This model-based map will be particularly useful for conservation and rangeland planning for future management and control of the plant through being able to predict which areas of the province are more likely to be high potential regions for the thickening of V. nilotica. 相似文献
57.
58.
Thomas Brabbs Debbie Collins Franck Hérard Matteo Maspero Dominic Eyre 《Pest management science》2015,71(1):7-14
This review summarises the literature on the biological control of Anoplophora spp. (Coleoptera: Cerambycidae) and discusses its potential for use in Europe. Entomopathogenic fungi: Beauveria brongniartii Petch (Hypocreales: Cordycipitaceae) has already been developed into a commercial product in Japan, and fungal infection results in high mortality rates. Parasitic nematodes: Steinernema feltiae Filipjev (Rhabditida: Steinernematidae) and Steinernema carpocapsae Weiser have potential for use as biopesticides as an alternative to chemical treatments. Parasitoids: a parasitoid of Anoplophora chinensis Forster, Aprostocetus anoplophorae Delvare (Hymenoptera: Eulophidae), was discovered in Italy in 2002 and has been shown to be capable of parasitising up to 72% of A. chinensis eggs; some native European parasitoid species (e.g. Spathius erythrocephalus) also have potential to be used as biological control agents. Predators: two woodpecker (Piciformis: Picidae) species that are native to Europe, Dendrocopos major Beicki and Picus canus Gmelin, have been shown to be effective at controlling Anoplophora glabripennis Motschulsky in Chinese forests. The removal and destruction of infested and potentially infested trees is the main eradication strategy for Anoplophora spp. in Europe, but biological control agents could be used in the future to complement other management strategies, especially in locations where eradication is no longer possible. © 2014 Crown copyright. Pest Management Science © 2014 Society of Chemical Industry 相似文献
59.
Jay E. Howell Clinton T. Moore Michael J. Conroy Richard G. Hamrick Robert J. Cooper Reggie E. Thackston John P. Carroll 《Landscape Ecology》2009,24(3):405-418
Large-scale habitat enhancement programs for birds are becoming more widespread, however, most lack monitoring to resolve
uncertainties and enhance program impact over time. Georgia’s Bobwhite Quail Initiative (BQI) is a competitive, proposal-based
system that provides incentives to landowners to establish habitat for northern bobwhites (Colinus virginianus). Using data from monitoring conducted in the program’s first years (1999–2001), we developed alternative hierarchical models
to predict bobwhite abundance in response to program habitat modifications on local and regional scales. Effects of habitat
and habitat management on bobwhite population response varied among geographical scales, but high measurement variability
rendered the specific nature of these scaled effects equivocal. Under some models, BQI had positive impact at both local farm
scales (1, 9 km2), particularly when practice acres were clustered, whereas other credible models indicated that bird response did not depend
on spatial arrangement of practices. Thus, uncertainty about landscape-level effects of management presents a challenge to
program managers who must decide which proposals to accept. We demonstrate that optimal selection decisions can be made despite
this uncertainty and that uncertainty can be reduced over time, with consequent improvement in management efficacy. However,
such an adaptive approach to BQI program implementation would require the reestablishment of monitoring of bobwhite abundance,
an effort for which funding was discontinued in 2002. For landscape-level conservation programs generally, our approach demonstrates
the value in assessing multiple scales of impact of habitat modification programs, and it reveals the utility of addressing
management uncertainty through multiple decision models and system monitoring. 相似文献
60.