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研究以大肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)、沙门氏菌(Salmonella)、枯草芽孢杆菌(Bacillussubtilis)、巨大芽孢杆菌(Bacillus magaterium)、蜡状芽孢杆菌(Bacillus magaterium)为指示菌,采用纸片法评估了臭柏(Sabina vulgaris Ant)精油废液对食品污染细菌的抑菌效果.结果表明,精油废液对大肠杆菌、金黄色葡萄球菌、沙门氏菌有抑制效果,且对大肠杆菌和沙门氏菌的抑菌效果较好;水蒸气蒸馏后的废液比共水蒸馏后的废液抑菌效果好.水蒸气蒸馏的废液随着蒸馏次数的增加,所含的有效成分越多,抑菌效果越好. 相似文献
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Analysis of antibiotic residues in liquid manure and leachate of dairy farms in Northern Germany 总被引:1,自引:0,他引:1
The scientific interest in the fate of antibiotic substances in the environment has increased during the past decades. Especially in animal husbandry, the assumed quantity of antibiotics excreted has caused major concerns as the environment can be contaminated by these compounds via different paths. In this study in Northern Germany, manure and leachate samples from dairy farms were analysed in order to verify if this kind of animal husbandry can be a source of antibiotic residues found in the environment. Neither in liquid manure nor in leachate were the analysed antibiotics detected. These results clearly show the minor importance of dairy cows as sources of antibiotic residues in the aquatic environment. To explain this fact, we propose the three following reasons: (i) the amount of antibiotics administered in dairy farming is low compared to pig or poultry production; (ii) manure storage is a useful process to minimize the antibiotic residues as the substances applied to dairy cows are sensitive to degradation processes during that period; (iii) excreted directly on grasslands, the substances degrade very quickly or adsorb to soil and are therefore not present in the leachate. 相似文献
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J. E. Parlevliet 《Euphytica》2007,153(3):353-362
Improved cultivars loose their identity and healthiness unless maintained properly. Contaminating and degrading forces, such
as outcrossing, volunteer plants, mixing, natural selection, mutation and seed-borne diseases, are at the root of this. Maintenance
selection can prevent this deterioration. How it is carried out depends on the reproduction system of the crop. Crops are
therefore classified into four categories; typical cross-pollinating crops, self-pollinating crops with a substantial amount
of outcrossing, typical self-pollinating crops with little outcrossing, and the vegetatively reproduced crops.
Generally some of the “breeder seed” is used to plant a small plot with spaced plants. A fair number of healthy plants of
the cultivar type is selected and the seed is harvested per plant. The progenies of the selected plants are grown in small
plots. Non-uniform or deviating plots and plots with a seed-borne disease are removed. The seed of the progenies that are
healthy, uniform and similar (and so of the cultivar type) are harvested per progeny to be tested next season on larger plots.
The same selection is applied and only the seed of the progenies that are healthy, uniform and similar are harvested together
to produce the “breeder seed”. The details of this maintenance selection vary with the reproduction system, the multiplication
rate of the crop and the possibilities available to the breeder. Seven crops, potato, common bean, barley, wheat, faba bean,
quinoa and maize are discussed here as they represent the different reproduction systems and multiplication rates, while being
important Andean food crops. 相似文献
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对北京市平原农区481眼深层井硝态氮含量进行了分析。结果表明,北京市平原农区深层地下水硝态氮(NO-3N)含量平均为5.74mgL-1,其中48.4%的调查机井受到人类活动的影响(NO-3N≥2mgL-1),21.0%的机井超过国际安全允许上限(NO-3N≥10mgL-1),8.1%的机井超过我国饮用水上限(NO-3N≥20mgL-1)。地下水位在120~200m的饮用水质量总体较好,硝态氮平均含量为5.16mgL-1,超标率为13.8%;而地下水位在70~100m的农灌水质量相对较差,硝态氮平均含量为5.98mgL-1,超标率为24.1%。近郊地下水质量劣于远郊,其中近郊饮用水超标率为38.7%,远郊为3.0%;近郊农灌水超标率为52.6%,远郊为15.3%。地下水硝态氮超标区域主要集中在老菜区。总体来看,北京市平原农区地下水硝态氮污染程度已超过欧美国家,必需及早采取有效措施加以控制。 相似文献
17.
Industrial activities in the river basin of the Elbe have a very long tradition, and have been resulting in the contamination
of sediments for centuries. Contamination lasted until the fall of the iron curtain; since then, the situation has improved
significantly. In the transition zone between freshwater systems and the marine environment, ports like Hamburg still have
to bear this burden of history. An overall (contaminated) management strategy should be developed in the context of the European
Water Framework Directive with the emphasis on source control.
Axel Netzband gave a keynote lecture during the SedNet Inaugural Conference, April 22–24, 2002, which forms the basis of this
article. 相似文献
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对桓台县区域农田监测研究表明,水肥管理不同的2个监测区域郭家区、李家区高产农田土体内NO_3~--N淋失迁移动态有差异,地下水污染亦不同。春天始土体内NO_3~--N含量趋于持续降低,浅层地下水NO_3~--N含量则持续升高,雨季后地下水中NO_3~--N含量尤剧烈升高,并达年内最高值,表现出农田N肥对地下水的直接污染,这可能与李家区灌溉次数多、土壤质地较轻和地下水位较浅有关。 相似文献
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