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111.
集约化畜禽养殖对环境的污染及防治研究 总被引:2,自引:0,他引:2
治理集约化畜禽养殖废弃物污染,开展废弃物的资源化利用,是解决中国畜牧业环境污染问题的主要路径。文章详述了中国畜禽养殖业污染问题的产生及对环境可能造成的影响,分析了畜禽废弃物处理措施与资源化利用的主要方式及其效果和存在的问题,并提出了控制畜禽粪污染物的对策和环境管理建议,将有助于推动中国畜禽养殖业的可持续发展,改善农业生态环境及农村人居环境。 相似文献
112.
Summary. Leaf disc choice and oviposition bioassays were used to examine the effects of larval experience with a Hoodia gordonii latex on subsequent behaviors. The latex deterred feeding and oviposition by “naïve” cabbage looper (Trichoplusia ni, Noctuidae) larvae and moths with no previous exposure to the material. “Experienced” insects, reared on a diet with the H. gordonii latex (1000 ppm), exhibited lesser feeding deterrence relative to naïve insects. Experienced female moths actually preferred to lay eggs on treated rather than control leaves. There was no observed transfer of behavioral preferences from experienced parents to their offspring. Our results suggest that moths may be acquiring oviposition preferences from larval feeding experience as described by Hopkins’ host selection principal (HHSP) or through chemical legacy. 相似文献
113.
干湿交替对福寿螺摄食和生长的影响 总被引:2,自引:0,他引:2
福寿螺(Pomacea canaliculata)被世界自然保护联盟列入世界100种恶性外来入侵物种黑名单,在我国南方已对水稻生产造成严重危害。为了探索通过水分调控来防治福寿螺的方法,本研究模拟福寿螺野外生存条件,探讨不同干湿交替条件下福寿螺摄食和生长的情况,来分析干旱胁迫对其体重增长率(Weight growth rate,WGR)、摄食率(Feeding rate,FR)、食物转化率(Food conversion ratio,FCR)、特定生长率(Specific growth rate,SGR)等的影响。结果表明:福寿螺在干湿交替条件下,其WGR、FR、FCR、SGR均受到明显抑制,甚至出现负值的情况;福寿螺的壳高随着有水时长的延长而增加,出现干旱时间越长,壳高增长越缓慢的现象;福寿螺在短时期干湿交替条件下发生部分补偿生长现象,这种补偿生长效应可能主要是通过饥饿后摄食水平提高而实现的,但超出一定限度时则不能补偿生长。根据上述结果,可以认为福寿螺在缺水条件下无法正常生长,且影响程度随着干旱时间的增加而增大。此外,福寿螺普遍会在旱后复水180min内钻出土壤,因此,可利用此时机防治福寿螺,及时避免其损伤水生作物。本研究结果可为稻田福寿螺的综合防治和水资源利用管理提供理论参考。 相似文献
114.
随着抗虫和耐草甘膦除草剂转基因玉米的迅速推广和种植,其环境安全性也越来越成为人们关注的焦点。为探讨抗虫耐除草剂转基因玉米C0030.3.5(外源基因cry1Ab和epsps)对水生动物环境的安全性,以模式生物大型蚤(Daphnia magna)为指示生物,分别使用1.5 g·L~(-1)C0030.3.5玉米粉和其非转基因对照DBN318玉米粉饲喂大型蚤28 d,探讨C0030.3.5玉米对大型蚤生长和繁殖的影响。结果显示,C0030.3.5玉米粉组大型蚤与亲本DBN318组大型蚤相比,体长、存活率、新生幼蚤总数等没有显著性差异(P0.05)。28 d饲喂实验结果表明,抗虫耐除草剂玉米C0030.3.5没有对大型蚤生长和繁殖产生不良影响。上述研究结果为转基因玉米的商业化种植和安全管理提供科学数据。 相似文献
115.
Tianyi Chen Wancong Gu Gen Li Qiuying Wang Peng Liang Xiaoyuan Zhang Xia Huang 《Frontiers of Environmental Science & Engineering》2018,12(1):6
In this study, super-fine powdered activated carbon (SPAC) has been proposed and investigated as a novel catalyst for the catalytic ozonation of oxalate for the first time. SPAC was prepared from commercial granular activated carbon (GAC) by ball milling. SPAC exhibited high external surface area with a far greater member of meso- and macropores (563% increase in volume). The catalytic performances of activated carbons (ACs) of 8 sizes were compared and the rate constant for pseudo first-order total organic carbon removal increased from 0.012 min–1 to 0.568 min–1 (47-fold increase) with the decrease in size of AC from 20 to 40 mesh (863 mm) to SPAC (~1.0 mm). Furthermore, the diffusion resistance of SPAC decreased 17-fold compared with GAC. The ratio of oxalate degradation by surface reaction increased by 57%. The rate of transformation of ozone to radicals by SPAC was 330 times that of GAC. The results suggest that a series of changes stimulated by ball milling, including a larger ratio of external surface area, less diffusion resistance, significant surface reaction and potential oxidized surface all contributed to enhancing catalytic ozonation performance. This study demonstrated that SPAC is a simple and effective catalyst for enhancing catalytic ozonation efficacy. 相似文献
116.
Centner TJ 《Environmental management》2001,28(5):599-609
Due to concentrations of animals at large facilities, animal feeding operations (AFOs) have emerged as a major potential source
of water pollution. The federal government regulates concentrated animal feeding operations under its point-source pollution
permitting regulations. A major determinant of whether an operation must apply for a permit is the number of animals at an
individual lot or facility. This paper examines federal mandatory controls and voluntary guidelines that seek to reduce contaminant
pollution from AFOs. Land treatment practices are delineated due to their importance in reducing the injurious by-products
of agricultural production. An evaluation of proposed revisions to federal regulations on confined animal feeding operations
suggests they diverge from their goal of controlling water pollution. Federal regulations focus on the size of operation and
amount of manure governed by the permitting process to the exclusion of other criteria related to the impairment of water
quality. Given the uncertainties about the amount of pollution from AFOs, lack of enforcement of existing regulations, localization
of problems, and possible alternatives for addressing the pollution, more demanding federal regulations may not form an appropriate
response. 相似文献
117.
Solid Waste Treatment as a High-Priority and Low- Cost Alternative for Greenhouse Gas Mitigation 总被引:5,自引:0,他引:5
The increased concern about environmental problems caused by inadequate waste management, as well as the concern about global
warming, promotes actions toward a sustainable management of the organic fraction of the waste. Landfills, the most common
means to dispose of municipal solid waste (MSW), lead to the conversion of the organic waste to biogas, containing about 50%
methane, a very active greenhouse gas (GHG). One unit of methane has a global warming potential of 21 computed for a 100-year
horizon or 56 computed for 20 years. The waste sector in Israel contributes 13% of total greenhouse gases (GHG) emissions
for a time horizon of 100 years (for a time horizon of 20 years, the waste sector contribution equals to more than 25% of
total GHG emissions). The ultimate goal is to minimize the amount of methane (CH4) by converting it to CO2. This can be achieved by physicochemical means (e.g., landfill gas flare, incineration) or by biological processes (e.g.,
composting, anaerobic digestion). Since the waste in Israel has a high organic material content, it was found that the most
cost-effective means to treat the degradable organic components is by aerobic composting (investment of less than US$ 10 to
reduce emission of one ton CO2 equivalent per year). Another benefit of this technology is the ability to implement it within a short period. The suggested
approach, which should be implemented especially in developing countries, could reduce a significant amount of GHG at relatively
low cost and short time. The development of a national policy for proper waste treatment can be a significant means to abate
GHG emissions in the short term, enabling a gain in time to develop other means for the long run. In addition, the use of
CO2 quotas will credit the waste sector and will promote profitable proper waste management. 相似文献
118.
119.
五滚柱式定向离合器是一种广泛用于机床、汽车、飞机及其他机械的装置。五滚柱式定向离合器的外环形状很不规则 ,其接触应力的计算为国内外工程界的难题之一。笔者采用弹性力学方法计算出了其接触应力 ,并用光弹性实验技术验证 ,理论计算的应力与实测结果基本吻合 相似文献
120.
胡斌梁 《中国安全科学学报》2003,13(11):52-54
超越离合器广泛用于汽车、机床及飞机等机械动力装置 ,其可靠性直接影响着机械动力装置的性能 ,特别是离合器出现疲劳、断裂的破坏性征兆 ,将产生严重的后果。滚柱式超越离合器外环形状很不规则 ,其内壁拉伸应力目前还没有一种很好的解析方法。笔者将外环简化为曲杆 ,计算所得结果与光弹性实验结果及电阻应变片实验结果吻合良好。 相似文献