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Bovine besnoitiosis is caused by Besnoitia besnoiti, an obligate intracellular apicomplexan parasite. Affected animals present cutaneous and systemic manifestations and the disease may lead to considerable economic losses. Although generally associated to tropical and subtropical areas, bovine besnoitiosis is now considered an emergent disease in Europe, due to the increasing number of new cases and apparent geographical expansion. In this study we evaluated the performance of a modified agglutination test (B-MAT) in the serodiagnosis of bovine besnoitiosis in comparison to the indirect immunofluorescent-antibody test (IFAT). To establish optimal protocol conditions we used bovine sera with a known infection status for B. besnoiti infection. Positive animals (n=36) presented B. besnoiti dermal cysts and anti-B. besnoiti specific antibodies, as determined by the indirect immunofluorescence test (IFAT). Negative animals (n=103) were from non-endemic areas in Portugal and negative by the IFAT. From here, we evaluated the sensitivity and specificity of the B-MAT relative to the IFAT with a panel of sera from herds with history of bovine besnoitiosis in Portugal, Spain and France (n=402), using three serum dilutions (1:80, 1:160, 1:320). Considering the positive cut-off at 1:160 serum dilution, the B-MAT showed an almost perfect test agreement with the IFAT; (κ=0.968; 95% CI: 0.941-0.996) with a relative sensitivity of 97.2% (95% CI: 94.1-100%) and a relative specificity of 99.3% (95% CI: 98.4-100%). As a simple and inexpensive technique the B-MAT represents a valuable tool for the diagnosis and study of the epidemiology of bovine besnoitiosis.  相似文献   
84.
Nineteen flocks of four poultry species were monitored at a veterinary field station to investigate the distribution and spread of Campylobacter genotypes between sequential and adjacent flocks. Caecal and liver samples were obtained at frequent intervals from birds of all flocks and examined for Campylobacter. Amplified fragment length polymorphism (AFLP) analysis was performed to genotype Campylobacter isolates. Of the 1643 caecal and liver samples investigated, 452 (27.5%) caecal samples and 11 (0.7%) liver samples contained Campylobacter. Of the caecal isolates 76.3% were identified as Campylobacter jejuni and 23.7% were identified as Campylobacter coli. Poultry flocks were largely colonized by more than one AFLP type and an intense exchange of Campylobacter genotypes between different poultry flocks occurred. These findings indicate that multiple genotypes can constitute the Campylobacter population within single poultry flocks, hinting to different sources of exposure and/or genetic drifts within the Campylobacter population. Nevertheless, in most flocks single Campylobacter genotypes predominated. Some strains superseded others resulting in colonization by successive Campylobacter genotypes during the observation period. In conclusion, the data demonstrate that the large genetic diversity of Campylobacter must be considered in epidemiological evaluations and microbial risk assessments of Campylobacter in poultry.  相似文献   
85.

Purpose  

The use of only one or a few species—representing an entire taxon—in ecotoxicological standard tests poses risk of underestimating the impact of toxicants on the environment. In earthworm ecotoxicity tests, the species Eisenia fetida or Eisenia andrei are commonly used, and there is evidence that these species respond relatively insensitive towards environmental pollution. With the present study, we wanted to evaluate the risk of underestimating effects of the insecticide imidacloprid in soil organisms by comparing E. fetida with two other earthworm species (Aporrectodea caliginosa and Lumbricus terrestris) regarding their sensitivities towards soil contaminated with this widely used insecticide.  相似文献   
86.
A rapid accurate and precise method for simultaneous determination of β-glucan and protein content in naked oat samples, based on the coupling of near-infrared spectroscopy and chemometrics, is presented. In particular, three different spectroscopic approaches [near infrared reflectance (NIR) and transmittance (NIT) on flour and NIT on whole grains] and various spectral pretreatments were considered. To account for the possibility of outlying samples, a robust version of the PLS algorithm (namely partial robust M-regression) was used. All the models resulted as accurate as the reference methods, reflectance spectroscopy being the technique providing the best outcomes. Variable reduction by inclusion of the most relevant predictors only (as evaluated by VIP scores) resulted in simpler and, in one case, more parsimonious models, without loss in accuracy.  相似文献   
87.
The slash-and-burn system is a subsistence agronomical practice widespread in tropical areas worldwide. This system has been extensively studied,especially for its impacts on agronomical aspects and soil physicochemical properties; however, knowledge of soil microbial diversity under slash and bum is scarce. In this study, for the first time, soil bacterial diversity of three locations from Central Mozambique, where slash and burn has been practiced for different durations of the forest fallow p...  相似文献   
88.
The use of organic amendments in agriculture could sustain crop production and preserve the agroecosystem, due to their importance in the conservation of organic matter in soil. The objective of this research was to evaluate the effects of differing organic fertilizers and of previous crops on lettuce growth, nutritional status and yields. The effects on soil characteristics were further investigated. The research was carried out during two years (2006 and 2007) at Metaponto (MT) in southern Italy, on lettuce crops cultivated after eggplant and melon to avoid their continuous cropping. The effects of application of a mineral fertilizer (MF), and of three treatments with organic fertilizers (commercial stable manure - OM; anaerobic digestate based on wine distillery wastewater - AD; composted municipal solid organic wastes coming from the separate collection - MSW) were studied. Head average weight, leaf area index, nitrate content and SPAD readings during the cropping cycles did not show significant differences among fertilizer treatments. On the contrary, marketable yield and head average weight at the harvest presented significantly different among the three organic fertilizers. The average marketable yield and head average weight of organic fertilizers experimental (AD and MSW treatments) decreased of 16 and 17%, respectively, compared to OM treatment. The previous melon crop influenced positively all analyzed parameters of the lettuce compared with previous eggplant crop. The previous melon crop reached the highest marketable yield with an increase of 59% compared with previous eggplant crop. Compared to the mineral fertilizer, the organic ones significantly increased the extracted fraction of soil organic carbon (6.9, 10.7 and 14.9% for OM, AD and MSW, respectively), without significant changes for the humic and fulvic content.  相似文献   
89.
The morphological variations (growth habit, leaf shape, leaf color, height, stem diameter, number of branches and internodes, leaf area, blade ratio, leaf thickness, number of leaves, and total leaf area) and protein content of 53 Indonesian amaranths (Amaranthus spp.), consisting of weedy-, vegetable-, and ornamental-types, were assessed. The extent of variation in the Indonesian Amaranthus accessions were compared with the worldwide collection (26 accessions from United States Department of Agriculture (USDA) and 5 ornamentals from Nepal) in the experimental field of the University of Tsukuba, Japan. The variation in average values of most morphological traits and protein content in the Indonesian accessions were similar to those of the worldwide germplasm, but the important parameters that influence vegetable yield (e.g., number of leaves and stem diameter) were superior in the Indonesian accessions. Protein content showed a positive correlation with the number of leaves, whereas a negative correlation was observed with leaf thickness. The Indonesian accession of A. viridis and A. dubius showed a great potential to be further selected as parental lines for high protein content and number of leaves. The relatively high protein content of the leaves of Celosia may also potentially serve as an alternative protein source in the tropics.  相似文献   
90.
? The concept of composting has always been rooted in a soil conservation philosophy that recognizes the role of organic matter in agriculture. The paradox has been that the recent rise in composting interest has come from the need for waste management solutions which emphasize economical and environmental alternatives, not the need for soil improvement and nutrient recycling. This review traces some early researches on the link between compost application and crop productivity and urges greater support for research that shows how compost can reduce pesticide use, improve farm economics and, in general, support the goals of sustainable agriculture.  相似文献   
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