全文获取类型
收费全文 | 7510篇 |
免费 | 363篇 |
国内免费 | 171篇 |
专业分类
安全科学 | 598篇 |
废物处理 | 100篇 |
环保管理 | 1955篇 |
综合类 | 3387篇 |
基础理论 | 458篇 |
环境理论 | 21篇 |
污染及防治 | 378篇 |
评价与监测 | 699篇 |
社会与环境 | 362篇 |
灾害及防治 | 86篇 |
出版年
2024年 | 9篇 |
2023年 | 47篇 |
2022年 | 74篇 |
2021年 | 134篇 |
2020年 | 245篇 |
2019年 | 120篇 |
2018年 | 104篇 |
2017年 | 189篇 |
2016年 | 212篇 |
2015年 | 202篇 |
2014年 | 326篇 |
2013年 | 370篇 |
2012年 | 340篇 |
2011年 | 544篇 |
2010年 | 321篇 |
2009年 | 435篇 |
2008年 | 334篇 |
2007年 | 431篇 |
2006年 | 435篇 |
2005年 | 283篇 |
2004年 | 293篇 |
2003年 | 334篇 |
2002年 | 304篇 |
2001年 | 297篇 |
2000年 | 327篇 |
1999年 | 261篇 |
1998年 | 196篇 |
1997年 | 194篇 |
1996年 | 125篇 |
1995年 | 101篇 |
1994年 | 95篇 |
1993年 | 108篇 |
1992年 | 59篇 |
1991年 | 34篇 |
1990年 | 23篇 |
1989年 | 20篇 |
1988年 | 12篇 |
1987年 | 13篇 |
1986年 | 18篇 |
1985年 | 14篇 |
1984年 | 14篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1975年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有8044条查询结果,搜索用时 688 毫秒
991.
The Piratininga Lagoon is a coastal, choked, and brackish ecosystem in SE Brazil, where uncontrolled discharge of domestic sewage led to eutrophication, increasing massive proliferation of benthic macroalgae, and decrease of the lagoon mean depth. In 1992, a dam was constructed by the local Municipality at its tidal channel aiming at stabilising its water level. Main physico-chemical parameters, together with macroalgae biomass, nutrient concentrations in the water column, particulate organic carbon, and chlorophyll a were recorded monthly at 4 sampling stations within the Piratininga lagoon from April 1994 to April 1995. The data, compared with “before-lock” existing studies, show that nutrients and chlorophyll a concentrations significantly increased after the lock construction. Based on the functioning of the ecosystem, we propose to harvest the algal mats before their decomposition period in order to partly remove the nutrient stocks from the lagoon and the future ecosystem modelling to predict the impact of natural and anthropogenic eutrophication. 相似文献
992.
993.
论长江流域生态危机与生态建设的对策 总被引:2,自引:0,他引:2
汪达汉 《长江流域资源与环境》1993,2(1):81-87
揭示了长江流域大面积山丘、水系生态系统普遍恶化,特别是中上游地区水土流失严重,以及因此而带来的一系列严重后果。根据史料、统计资料及实测成果等,分析了生态环境恶化的原因,着重研究了水土流失等生态失调现象与森林植被的紧密关系及其演变规律,探讨了进行绿色生态建设的必要性、可能性与可行性。最后提出了建设长江流域防护林体系的宏观战略和微观措施。 相似文献
994.
An 11-year period of water quality data, collected by the Directorate of Sate Water Works of Turkey are thoroughly analyzed
for the purpose of implementing water quality classes to water resources in the Meric Basin, located on the European land
mass of Turkey. Water quality parameters are divided into four groups as physical, organic, inorganic, and bacteriological.
The quality class of each group is evaluated by taking into account the poorest quality of any parameter in the group, after
which a quality rank is assigned to the sampling station and the waterbody in question. This method of water quality classification
imposed by the Turkish Water Quality Act, is then criticized with respect to a statistical approach. 相似文献
995.
996.
Ye Suping Li Yanshun Department of Law Suzhou University Suzhou Jiangsu China 《中国人口.资源与环境(英文版)》2006,4(4)
Economic development has made a negative impact on the environment.However,our proceedings on public interest action are almost blank,causing many of the cases related to the environmental protection to be rejected by the court for the reason that the prosecutors fail to provide enough evidence.Therefore,we can take the U.S.system of civil action for reference to improve our public interest action while employing proxy litigation.The measures can be included as follows:relax the plaintiff qualifications;establish the necessary lead procedures;invert the responsibility of providing evidence. 相似文献
997.
罗正齐 《长江流域资源与环境》1993,2(2):173-175
长江上游攀西——六盘水地区是个资源富集的“金三角”。通过交通先行,加快资源开发,对增强21世纪经济发展后劲意义重大。但生态环境恶化,急需加强保护。 相似文献
998.
对燃煤电厂的环评工作中,项目选址、总平面布置、污染防治与清洁生产:冷却塔噪声等一些值得注意的问题进行了探讨,并提出了一些初步意见。 相似文献
999.
The development of the environmentally conserving dike-pond system of integrated agriculture and aquaculture in the Zhujiang Delta of south China is traced to illustrate the impact of environmental changes on technological innovations. The technologies of dike building, land reclamation, pond fish culture, and crop cultivation on dikes, which were either independently developed or modified from ideas brought in by migrant farmers from northern China, represented farmers' efforts to adapt to the new characteristics of a changed environment as population pressure increased. The new technologies revealed the farmers' awareness of the need for environmental conservation. However, increased population pressure also necessitated more intensive use of the land, both in the highland and lowland regions, giving rise to inappropriate dike building and premature reclamation activities, which in turn brought about more frequent flooding in the delta region. Careless application of a new technology tended to have harmful effects on the environment. Political conditions in different periods of China's economic development have also caused changes in the dike-pond system which has to maintain high productivity and profitability. Recent advances in dike-pond system technology have focused on crop diversification and animal husbandry to match the three-dimensional characteristics of its ecological components. New agricultural technologies can be successful in China only if they can provide a balance between land use and conservation. 相似文献
1000.
李爱年 《中国人口.资源与环境》2002,(5)
生态保护法属于环境保护法的一个组成部分。目前 ,我国生态保护法律体系已基本形成 ,但还不十分完善 ,与生态保护和经济发展的要求还不相适应。本文针对生态保护法体系中存在的问题 ,提出进一步完善的建议 ,以促进我国生态保护事业的发展 相似文献