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排序方式: 共有153条查询结果,搜索用时 15 毫秒
41.
Skinner MA Keen DL Parlane NA Hamel KL Yates GF Buddle BM 《Research in veterinary science》2005,78(3):1-236
Possums are a wildlife vector of bovine tuberculosis in New Zealand. Vaccination of possums with BCG is being considered as a measure to control the spread of bovine tuberculosis to cattle and deer. Delivery via oral bait is feasible but BCG is degraded in the stomach. The aim was to determine whether ranitidine (Zantac) would reduce gastric acidity and enhance the efficacy of intragastrically administered BCG. A dose of 75 mg reduced gastric acidity for at least 4 h. Thus, possums were vaccinated intragastrically with BCG after receiving 75 mg ranitidine or ranitidine or BCG alone, as controls, before challenge with virulent Mycobacterium bovis. Proliferative responses of blood lymphocytes to M. bovis antigens after vaccination were significantly higher in possums given ranitidine/BCG compared to controls and seven weeks after challenge they had significantly lower lung weights and spleen bacterial counts than ranitidine alone controls. Vaccination with BCG alone only gave a reduction in loss in body weight. Agents that reduce gastric acidity may be useful in formulating BCG for oral bait delivery to wildlife for vaccination against bovine tuberculosis. 相似文献
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AIM: To investigate two single nucleotide polymorphisms (SNP) in the apolipoprotein(a) promoter at positions -418 and -384 and to compare distributing difference of genotype frequencies of single nucleotide among different races and to explore the influencies of them on serum lipid level and their association with coronary heart disease (CHD). METHODS: Using PCR-RFLP (BsgI,BfaI) method, we determined genotypes of these two SNPs in 156 unrelated healthy controls of HanZu Chinese and 56 unrelated CHD patients of HanZu Chinese and 56 unrelated African Blacks, then cloned polymerase chain reaction (PCR) products into T-vector and sequenced it by M13 currency primer, correspondingly. RESULTS: (1) There was no polymorphism at position -418A/A and -384C/C in control group. Only one CHD patient's genotype determined was -418G/G, other were -418A/A and -384C/C in CHD patients. (2) Only two African Blacks' genotype determined was -418G/G, other were -418A/A and -384C/C in African Blacks. (3) However, the Apo(a) promoter sequence was in coincident with the sequence publicized in GenBank and the base at positions -418 was adenine (A) and -384 was cytosine (C). CONCLUSION: The mutation frequencies at position -418 and -384 were low in the Chinese Han Population of Hubei and perhaps no single nucleotide polymorphisms was at two positions. No association with serum lipid levels and CHD was observed. There were great variabilities to the SNPs in the Apo(a) promoter among different races. 相似文献
44.
The possible transovarial transmission of two phytoplasmas, ' Candidatus Phytoplasma mali' and ' Candidatus Phytoplasma prunorum', through their respective psyllid vectors Cacopsylla melanoneura and Cacopsylla pruni , was investigated. Different life stages of the progeny of infected female psyllids were analysed by PCR detection of phytoplasma DNA. While ' Ca. Phytoplasma mali' could not be detected in any of the C. melanoneura life stages tested, ' Ca. Phytoplasma prunorum' could be detected in eggs, nymphs and newly emerged adults of C. pruni . Infectivity tests using both nymphs and newly emerged adults of C. pruni showed that ' Ca. Phytoplasma prunorum' inherited from infected females can be transmitted to healthy plum plants. Although further validations are required, these findings open up new perspectives on the study of the epidemiology of diseases associated with European stone fruit yellows. 相似文献
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José Francisco Nieto-Cabrales Beatriz Salceda-Sánchez Héctor M. Zazueta-Islas Marlene Solís-Cortés Magaly Guadalupe Landa-Flores Juan Carlos del Mazo-López Laura Valtierra-Alzaga Juan J. Soto-Gutiérrez Heron Huerta-Jimenez Ingeborg Becker Jorge J. Rodríguez-Rojas Sokani Sánchez-Montes 《Zoonoses and public health》2024,71(2):217-224
47.
Vegetation Composition and Succession of Abandoned Farmland: Effects of Ecological,Historical and Spatial Factors 总被引:6,自引:0,他引:6
In North America, as well as in Europe, the mechanization and the modernization of the agricultural activities had strongly
modified the agricultural landscapes. Originating from these transformations of the agricultural environment, abandoned farmlands
remain poorly known environments. A holistic approach, including the analysis of ecological, historical and spatial factors,
is used in order to understand the dynamics of these environments created by agricultural abandonment in southwestern Québec
(Canada). The analysis of 36 abandoned farmlands in the study area reveals the existence of two ecological groups. The first
ecological group is composed by abandoned farmlands originating from pasture and at the moment dominated by a spiny shrub
vegetation. The second ecological group includes past cultivated field at the moment dominated by either hydric herbaceous
and shrub vegetation. Abiotic ecological variables such as slope, surface stoniness, canopy opening and soil pH, as well as
land-use history, and age of the abandoned farmlands, are major factors explaining the current state of abandoned farmlands.
Succession vector analysis reveals a strong differentiation among abandoned farmlands as to their tree species regeneration.
Possible management alternatives, such as reforestation, are proposed in order to integrate those new environments to the
modern agricultural landscape. 相似文献
48.
Roger A.C. Jones 《Integrated Pest Management Reviews》2001,6(1):15-46
There is a need to develop integrated disease management strategies that are comprehensive and can protect farmers from the economic hardship that arises when epidemics of non-persistently aphid-borne viruses damage their crops. The aim of this review is to provide a model for future programmes to use when developing such strategies for different combinations of non-persistently aphid-borne viruses and crops. The model programme described is a 15-year study to develop integrated management strategies against two non-persistently aphid-borne viruses causing damaging diseases of lupins and to get them adopted by farmers. The success of the programme depended on an interdisciplinary team approach, obtaining a detailed understanding of the factors favouring virus epidemics, field evaluation for virus resistance, and field experiments that determined the effectiveness of individual control measures. The strategies developed were designed to cause few additional labour demands, and minimal disruption to normal farming operations or extra expense.The programme devised integrated management strategies for the diseases caused by Cucumber mosaic virus (CMV) and Bean yellow mosaic virus (BYMV) in crops of narrow-leafed lupin (Lupinus angustifolius) under the conditions of low-input, dryland agriculture in the south-west Australian grainbelt, which has a Mediterranean-type climate. CMV is introduced into lupin crops by sowing virus-infected lupin seed while aphids spread BYMV into the growing crop from adjacent virus-infected, clover-based pastures. Grain yield losses are substantial when virus spread by aphids is sufficient to cause high incidences of infection within crops. The management strategies were gradually improved and expanded as understanding of the epidemiology of viruses in lupins improved and the results of field experiments involving potential control measures became available. The individual measures combined within the integrated management strategy for each virus were: sowing seed stocks with minimal virus contents, sowing cultivars with inherently low seed transmission rates and isolation from neighbouring lupin crops (CMV only); perimeter non-host barriers and avoiding fields with large perimeter : area ratios (BYMV only); nobreak promoting early canopy development, generating high plant densities, adjusting row spacing, direct drilling into retained stubble, sowing early maturing cultivars, maximising weed control and crop rotation (both viruses). Recommendations to apply insecticide were included solely for spraying high value seed crops (CMV only) or virus-infected pastures next to crops (BYMV only). The justification for selection of each individual control measure, its mode of action in either removing or minimising the virus infection source or suppressing virus spread by aphids and the extent to which it has been adopted by farmers is described. The approach used to transfer the strategies to farmers and the need to avoid complacency following the overall success of the work is emphasised. An integrated disease management strategy developed to clean up the lupin breeding programme from seed-borne virus infection and prevent release of infected seed stocks of new cultivars is also described. It can serve as an example of what is needed to tackle seed-borne virus contamination in other plant breeding or selection programmes. 相似文献
49.
Lethal disease (LD) is a lethal yellowing-type disease of coconuts associated with phytoplasmas in Tanzania, but the insect vector for it has not yet been identified. In this study, the auchenorrynchous insects in LD-infected coconut fields were surveyed to determine potential vectors for the disease. No significant correlation was found between disease incidence and numbers of insects collected from the field, possibly reflecting the unknown incubation period for the disease. However, analysis of more than 5000 individual insects by the polymerase chain reaction (PCR), using LD-specific primers derived from the phytoplasma 16S rRNA gene, revealed PCR products of the correct size from eight individuals of Diastrombus mkurangai and four of Meenoplus spp. When digested with restriction endonucleases, fragments of the same size as the LD phytoplasma were obtained. No PCR products were detected in any of the other insect species tested. These results implicate D. mkurangai and Meenoplus spp. as probable vectors of the LD phytoplasma. 相似文献
50.