全文获取类型
收费全文 | 1451篇 |
免费 | 54篇 |
国内免费 | 161篇 |
专业分类
安全科学 | 115篇 |
废物处理 | 84篇 |
环保管理 | 855篇 |
综合类 | 372篇 |
基础理论 | 82篇 |
污染及防治 | 52篇 |
评价与监测 | 65篇 |
社会与环境 | 13篇 |
灾害及防治 | 28篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 14篇 |
2021年 | 16篇 |
2020年 | 21篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 11篇 |
2016年 | 13篇 |
2015年 | 11篇 |
2014年 | 18篇 |
2013年 | 14篇 |
2012年 | 14篇 |
2011年 | 27篇 |
2010年 | 26篇 |
2009年 | 20篇 |
2008年 | 50篇 |
2007年 | 10篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 36篇 |
2003年 | 70篇 |
2002年 | 158篇 |
2001年 | 140篇 |
2000年 | 169篇 |
1999年 | 134篇 |
1998年 | 102篇 |
1997年 | 80篇 |
1996年 | 213篇 |
1995年 | 57篇 |
1994年 | 17篇 |
1993年 | 12篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 9篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 22篇 |
1984年 | 38篇 |
1983年 | 35篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 7篇 |
1978年 | 5篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1971年 | 14篇 |
1967年 | 1篇 |
排序方式: 共有1666条查询结果,搜索用时 221 毫秒
251.
Marc Hockings 《Environmental management》1998,22(3):337-345
/ An approach to evaluating the effectiveness of management of protected areas is proposed. This approach has been used in developing an evaluation strategy for the Fraser Island World Heritage Area in Australia. The main component of the strategy is built upon the desired outcomes specified in the management plan for the area and thus provides a basis for assessing the extent to which the plan's objectives are being achieved. A series of monitoring programs have been proposed to enable this assessment. Examples of monitoring programs developed as part of the evaluation strategy are presented. A second component of the strategy monitors the implementation of the management plan. A management information system has been developed to record and report on the extent to which the specific actions specified in the management plan have been implemented. The strategy is discussed in relation to seven objectives set for the evaluation program in its design phase.KEY WORDS: Planning; Evaluation; Monitoring; Management; Protected areas 相似文献
252.
/ Public contact is a vital component of any program to manage natural resources. A well-planned public contact program uses a variety of strategies to create a sympathetic and environmentally aware public and to meet specific management-related objectives. A methodology is proposed that can be applied to planning public contact at any level, from media design for a specific project to corporate strategies for communication. The methodology integrates management-driven, client-driven and resource-driven planning to provide the connections essential to effective communication.KEY WORDS: Planning; Public contact; Interpretation; Conservation; Management 相似文献
253.
James Fielding Smith 《Environmental management》1998,22(2):263-276
/ Questionnaires from 39 state National Pollutant Discharge Elimination System (NPDES) agencies were analyzed using principal component analysis and multiple regression. Decentralized programs scored better in a fundamental indicator of efficiency (lower percentage of expired permits) and in the key effectiveness measure of unit-cost compliance achieved. In no case did centralized states score significantly better than decentralized ones. These results indicated support for the theory that superior local knowledge is the key mechanism. Case studies of five states suggested internal program adjustments may cause outcomes to converge towards efficiency and effectiveness, perhaps explaining the large number of variables showing no difference between centralized programs and decentralized ones.KEY WORDS: NPDES; Compliance; Decentralization; Outcome; Efficiency; Unit-cost analysis 相似文献
254.
255.
海水水质评价的物元分析法 总被引:6,自引:1,他引:6
为了探索物元分析方法用于海水水质综合评价的可能性,通过计算海不水质对各评论评价等级的综合关联度,进行海水水质综合评价。用物元分析法对5个监测站位的海水水质进行评价,结果表明它用于海水水质综合评价是可行的。 相似文献
256.
我国近海是经济增长和发展最重要和最集中的区域。然而,随着沿海工业的发展,大量未经处理的陆源污染物随间排海,沿岸水域形成“黑潮”、“赤潮”致使我国近海海域污染加剧,生态平衡失调,严重影响了海域资源环境的可持续发展。 相似文献
257.
赣闽浙三省接合区砂金资源分布广泛,尤以赣东北乐安江、昌江水系最富。本文是在对该区野外调查,取样分析和典型砂金矿床、矿点地质环境分析的基础上,认为冲积型砂金富集与矿源层分布,水系发育规模及地貌条件,含金物质搬运距离,水动力条件,沉积界面微地貌及合金物质沉积后埋藏状况有密切关系,掌握砂金沉积学特点有利于资源的勘探和开发。 相似文献
258.
浙江墩头盆地横山组孢粉化石的发现及其地层意义 总被引:1,自引:0,他引:1
浙江墩头盆地红色岩层中上部首获丰富的以Cassopllis为主(58.39—62.54%)伴有Exesipollenites(15.21—15.84%),Hsuisporites(0.56—0.62%),Cicatricosisporites(0—0.31%)等孢粉化石。该孢粉组合特征既与国内外晚侏罗世孢粉组合面貌差别较大,又与早白垩世中晚期孢粉组合面貌存在明显差异,显示了早白垩世早期孢粉组合的色彩。笔者认为这套红色岩层应归早白垩世早期横山组为宜。 相似文献
259.
The aerobic visible-light-photosensitised irradiation of methanolic solutions of either of the phenolic-type contaminants model compounds (ArOH) p-phenylphenol (PP), p-nitrophenol (NP) and phenol (Ph), and for two additional phenolic derivatives, namely p-chlorophenol (ClP) and p-methoxyphenol (MeOP), used in some experiments, was carried out. Employing the natural pigment riboflavin (Rf) as a sensitiser, the degradation of both the ArOH and the very sensitiser was observed. A complex mechanism, common for all the ArOH studied, operates. It involves superoxide radical anion (O2√−) and singlet molecular oxygen (O2(1Δg)) reactions. Maintaining Rf in sensitising concentrations levels (≈0.02 mM), the mechanism is highly dependent on the concentration of the ArOH. Kinetic experiments of oxygen and substrate consumption, static fluorescence, laser flash photolysis and time-resolved phosophorescence detection of O2(1Δg) demonstrate that at ArOH concentrations in the order of 10 mM, no chemical transformation occurs due to the complete quenching of Rf singlet excited state. When ArOH is present in concentrations in the order of mM or lower, O2√− is generated from the corresponding Rf radical anion, which is produced by electron transfer reaction from the ArOH to triplet excited Rf. The determined reaction rate constants for this step show a fairly good correlation with the electron-donor capabilities for Ph, PP, NP, ClP and MeOP. In this context, the main oxidative species is O2√−, since O2(1Δg) is quenched in an exclusive physical fashion by the ArOH. The production of O2√− regenerates Rf impeding the total degradation of the sensitiser. This kinetic scheme could partially model the fate of ArOH in aquatic media containing natural photosensitisers, under environmental conditions. 相似文献
260.
A model for predicting the distribution of dibenzofuran and polychlorinated dibenzofuran (PCDF) congeners from a distribution of phenols was developed. The model is based on a simplified chemical mechanism. Relative rate constants and reaction order with respect to phenol precursors were derived from experimental results using single phenols and equal molar mixtures of up to four phenols. For validation, experiments were performed at three temperatures using a distribution of phenol and 19 chlorinated phenols as measured in municipal waste incinerator exhaust gas. Comparison of experimental measurements and model predictions for PCDF isomer distributions and homologue pattern shows agreement within measurement uncertainty. The R-squared correlation coefficient exceeds 0.9 for all PCDF isomer distributions and the distribution of PCDF homologues. These results demonstrate that the distribution of dibenzofuran and the 135 PCDF congeners from gas-phase condensation of phenol and chlorinated phenols can be predicted from measurement of the distribution of phenol and the 19 chlorinated phenol congeners. 相似文献