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排序方式: 共有159条查询结果,搜索用时 295 毫秒
141.
DAVID P. EDWARDS FELICITY A. ANSELL ABDUL H. AHMAD REUBEN NILUS KEITH C. HAMER 《Conservation biology》2009,23(6):1628-1633
Abstract: The recent advent of carbon crediting has led to a rapid rise in biosequestration projects that seek to remove carbon from the atmosphere through afforestation and forest rehabilitation. Such projects also present an important potential opportunity to reverse biodiversity losses resulting from deforestation and forest degradation, but the biodiversity benefits of different forms of biosequestration have not been considered adequately. We captured birds in mist nets to examine the effects of rehabilitation of logged forest on birds in Sabah, Borneo, and to test the hypothesis that rehabilitation restores avian assemblages within regenerating forest to a condition closer to that seen in unlogged forest. Species richness and diversity were similar in unlogged and rehabilitated forest, but significantly lower in naturally regenerating forest. Rehabilitation resulted in a relatively rapid recovery of populations of insectivores within logged forest, especially those species that forage by sallying, but had a marked adverse effect on frugivores and possibly reduced the overall abundance of birds within regenerating forest. In view of these results, we advocate increased management for heterogeneity within rehabilitated forests, but we strongly urge an increased role for forest rehabilitation in the design and implementation of a biodiversity‐friendly carbon‐offsetting market. 相似文献
142.
水生生物群落功能结构研究不仅是河流生态学的基础,也有助于更好地剖析水生生物对环境压力的响应关系.为探明土地利用对大型底栖动物FFGs(功能摄食类群)的影响,于2009年5月对太子河流域47个采样点(6个参照样点、41个受损样点)的大型底栖动物进行调查,分析其FFGs结构及与流域土地利用类型(森林用地、草业用地、农业用地和城镇用地)和环境因子的关系.结果表明:①受损样点的ALT(海拔)、WT(水温)、EC、ρ(NH4+-N)和ρ(PO43--P)均显著高于参照样点.②受损样点捕食者、刮食者与撕食者的相对丰度、丰富度及密度、直接收集者丰富度、刮食者的Shannon-Wiener指数及Pielou指数、直接收集者与捕食者Margalef指数和刮食者Simpson指数均显著低于参照样点,而直接收集者的相对丰度则显著高于参照样点.③Spearman相关性分析结果表明,农业用地和城镇用地比例增加会造成河流水质恶化及大型底栖动物FFGs结构发生变化.④CCA结果表明,EC是影响大型底栖动物FFGs结构分布的主要环境因子.研究显示,大型底栖动物FFGs对太子河流域农业活动与城镇化的响应敏感,可以为利用大型底栖动物FFGs监测流域环境压力提供理论支持. 相似文献
143.
144.
根据邯郸市经济发展,了解农林牧渔业和畜禽养殖业之间的关系及所占其比重;调查分析畜禽养殖业现状和发展趋势及分布情况,摸清主要畜禽养殖区域及养殖种类;根据不同养殖种类、污染物产生量、主要污染途径、环境管理现状以及存在主要环境问题,因地制宜,相关部门密切配合,坚持污染防治与生态养殖并重,采取合理的污染防治措施及对策,加强环境管理,合理规划养殖区,调整农业产业结构,切实解决畜禽养殖与环境保护协调发展的矛盾.保护区域生态环境,保持邯郸市畜禽养殖业健康发展,是首要关注的问题. 相似文献
145.
Mfon T. Udo 《环境科学学报(英文版)》2002,14(1):95-101
Between April 1992 and March 1993,intersexual plasticity in aspects of the biology of the mudskipper,Periophthalmus barbarus was studied.Sec was differentiated on the basis of the genital papillae,it was broader in females than males.Sexually active females were slightly heavier than similarly-sized males.Sex ratio was strongly female-biased.Length-weight relationship of the sexes was isometric.There was no significant difference in the feeding intensity of both sexes;uniformity was also apparent in diet breadth.There was no named sex-based difference in hepatosometic index but condition index was higher in males than females.the uniformity in intersexual plasticity of P.barbarus is consequent upon homogeneity of the mangrove ecosystem,which can only be altered anthropogenically. 相似文献
146.
Summary. The effect of rearing larvae of Trichoplusia ni on
individual feeding deterrents or on binary mixtures of deterrents
on their subsequent gustatory sensitivity was measured
in paired choice leaf disc bioassays. Our working hypothesis
was that mixtures of antifeedants (pure allelochemicals)
would mitigate decreased feeding deterrent response following
prolonged exposure in this generalist herbivore. Neonate
larvae were reared on cabbage leaves treated with individual
feeding deterrents (digitoxin, thymol, toosendanin or xanthotoxin),
or with binary mixtures of these until the third instar.
Feeding deterrent responses to each antifeedant or mixture
was then determined in a leaf disc choice bioassay. All of the
mixtures produced additive deterrence when presented to
naïve larvae. Larvae reared on individual antifeedants
showed a significantly decreased feeding deterrent response
(except to digitoxin), whereas larvae reared on binary mixtures
of antifeedants did not show a decreased feeding deterrent
response to any of them. Such mixtures were synergistic
in terms of their feeding deterrence to experienced larvae.
Our experiment supports the hypothesis (Jermy 1986) that
mixtures of deterrents can prevent decreased feeding deterrent
response following prolonged exposure, and provides one
explanation for the multiplicity of chemical defenses found
in many plants. 相似文献
147.
利用混合菌群活性污泥法实现生物可降解塑料PHA的合成 总被引:4,自引:0,他引:4
PHA是一种生物可降解塑料,可从污水有机物中合成。文章在简要说明现阶段工业生产PHA情况的基础上,总结了利用混合菌种活性污泥法从污水有机物中合成PHA的优点。重点对两种从污水中生产PHA工艺——厌氧-好氧活性污泥工艺和好氧瞬时供料工艺进行了介绍,并给出了相应工艺流程。通过使用廉价的有机底物可以使PHA的生产价格降低到原来的一半,大约为每公斤4欧元左右。文章还讨论了控制工艺运行条件对PHA合成的重要性,并说明了不同底物组成对合成PHA性质的影响。 相似文献
148.
不同光照度下南方鲇稚鱼的摄食强度及摄食动力学 总被引:7,自引:0,他引:7
谢从新 《应用与环境生物学报》2002,8(3):267-269
在10^3-10^-1lx光照度范围内,南方鲇稚鱼对团鲂鱼苗的摄食强度随光照度减弱而增强,在10^9lx时达最大值,随后下降,摄食率在开始摄食后10min,光照强度为10^0lx时最同,并随摄食时间延长而下降。 相似文献
149.
中国牦牛品种资源的研究进展 总被引:8,自引:0,他引:8
论文通过对大量的资料和论文查阅、分析和总结,以牦牛资源近十几年研究和生产为线索,从牦牛的资源研究现状、生态生理生化、遗传、种间杂交、本品种选育、野牦牛资源及利用、生产性能、营养及饲养管理、产品品质分析和开发利用以及牦牛疾病等研究内容着手,较全面而系统地阐述了我国牦牛科学近十几年的研究进展,并总结了牦牛科研和生产中存在的主要问题,为了解牦牛科学发展及对今后牦牛科研和生产具有一定的参考价值。 相似文献
150.
Bernard Rollin 《Journal of Agricultural and Environmental Ethics》2001,14(1):29-37
The issue of regularly feeding low levels of antibiotics to farm animals in order to increase productivity is often portrayed as a dilemma. On the one hand, such antibiotic use is depicted as a necessary condition for producing cheap and plentiful food, such that were such use to stop, food prices would rise significantly and our ability to feed people in developing nations would decrease. On the other hand, such antibiotic use seems to breed antibiotic resistance into pathogens affecting human health. Resolving this dilemma, it is alleged, will require great amounts of research into risk/benefit assessment. Contrary to this claim, we will argue that society has all the data it needs to make a reasonable ethical decision, which would be curtailing such use. Such curtailment will not harm consumers significantly, will not harm developing nations' evolving agriculture, and could produce hitherto unnoticed benefits, namely restoring the possibility of a more husbandry-based, sustainable agriculture to replace the high-tech agriculture that has hurt animals, the environment, small farms, and sustainability. 相似文献