全文获取类型
收费全文 | 3502篇 |
免费 | 59篇 |
国内免费 | 53篇 |
专业分类
安全科学 | 145篇 |
废物处理 | 215篇 |
环保管理 | 354篇 |
综合类 | 605篇 |
基础理论 | 602篇 |
环境理论 | 2篇 |
污染及防治 | 1083篇 |
评价与监测 | 352篇 |
社会与环境 | 224篇 |
灾害及防治 | 32篇 |
出版年
2023年 | 41篇 |
2022年 | 88篇 |
2021年 | 117篇 |
2020年 | 62篇 |
2019年 | 54篇 |
2018年 | 128篇 |
2017年 | 142篇 |
2016年 | 162篇 |
2015年 | 109篇 |
2014年 | 173篇 |
2013年 | 311篇 |
2012年 | 186篇 |
2011年 | 243篇 |
2010年 | 181篇 |
2009年 | 161篇 |
2008年 | 210篇 |
2007年 | 177篇 |
2006年 | 165篇 |
2005年 | 148篇 |
2004年 | 128篇 |
2003年 | 116篇 |
2002年 | 91篇 |
2001年 | 68篇 |
2000年 | 41篇 |
1999年 | 39篇 |
1998年 | 24篇 |
1997年 | 16篇 |
1996年 | 10篇 |
1995年 | 19篇 |
1994年 | 16篇 |
1993年 | 17篇 |
1992年 | 19篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 12篇 |
1987年 | 3篇 |
1986年 | 9篇 |
1985年 | 14篇 |
1984年 | 8篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1977年 | 3篇 |
1966年 | 3篇 |
1962年 | 7篇 |
1961年 | 4篇 |
1959年 | 3篇 |
排序方式: 共有3614条查询结果,搜索用时 484 毫秒
121.
Conservation of the Toromiro Tree: Case Study in the Management of a Plant Extinct in the Wild 总被引:1,自引:0,他引:1
Mike Maunder Alastair Culham † Bjorn Alden ‡ Georg Zizka § Cathérine Orliac Wolfram Lobin †† Alberto Bordeu ‡‡ Jose M. Ramirez §§ and Sabine Glissmann-Gough 《Conservation biology》2000,14(5):1341-1350
Abstract: We reviewed the history and conservation of Sophora toromiro , a species that has been extinct in the wild since 1960 but has survived as scattered individuals in botanic gardens and private collections. The short-term conservation of S. toromiro is dependent on the management of surviving ex situ stocks. This is being achieved through international collaboration by a working group established to coordinate the conservation management of the species. Molecular evidence indicates that the species retains greater genetic variability than expected. The greatest amount of genetic variability was located in specimens outside botanic garden collections. No unmodified natural habitat survives on Rapa Nui ( Easter Island); so opportunities to establish a viable wild population are limited. Evidence from past reintroductions indicates that the best short-term opportunity for the species is through conventional horticultural management in botanic gardens and traditional farm plots on Rapa Nui. Some extinct-in-the-wild taxa (sensu World Conservation Union 1994), such as the Toromiro, retain genetic variability, and appropriate reintroduction sites exist. These taxa represent valid priorities for conservation management. 相似文献
122.
Thomas Eisner Maria Eisner Daniel J. Aneshansley Chia-Li Wu Jerrold Meinwald 《Chemoecology》2000,10(4):211-216
Summary. The mint plant, Teucrium marum (family Labiatae), sometimes called cat thyme, contains two methylcyclopentanoid monoterpenes, dolichodial and teucrein. The former compound is potently anti-insectan. It is repellent to ants (Monomorium pharaonis) and induces preening reflexes in flies (Phormia regina) and cockroaches (Periplaneta americana). Evidence is presented suggesting that dolichodial, which is presumed to be the plant's chief defensive agent, is stored in the tiny epidermal capsules that beset the leaves. It is only when the leaves are injured (and the capsules ruptured) that the leaves become repellent. Teucrein, in contrast, has no anti-insectan potency. It is present predominantly in the leaf buds, unlike dolichodial, which is present mostly in mature leaves. It is argued that teucrein is the storage compound from which dolichodial is generated during leaf development. 相似文献
123.
Matiatos Ioannis Varouchakis Emmanouil A. Papadopoulou Maria P. 《Environmental Modeling and Assessment》2019,24(6):659-675
Environmental Modeling & Assessment - Benchmarking of different numerical models simulating groundwater flow and contaminant mass transport is the aim of the present study, in order to... 相似文献
124.
Lea Nicita Giovanni Signorello Maria De Salvo 《Journal of Environmental Planning and Management》2016,59(7):1225-1237
This paper applies the Kuhn–Tucker model to estimate recreation demand of parks in Sicily. We estimate a fixed coefficient specification and a random coefficient specification to take into account heterogeneity across visitors. Estimates suggest a diversity of preferences across the population and that parks with higher level of quality attributes are more likely to be visited. We also simulate two sets of hypothetical policy scenarios to evaluate and compare the recreational value of each park and the welfare impacts of changes in a quality attribute. 相似文献
125.
126.
127.
128.
Result-oriented approaches to the management of drinking water catchments in agricultural landscapes
Alexander Wezel Maria Zipfer Christine Aubry Fabienne Barataud Alois Heißenhuber 《Journal of Environmental Planning and Management》2016,59(2):183-202
Management of water quality in drinking water catchments is of ongoing, high importance as nitrate concentrations are often still very high. We analysed the Augsburg catchment in Germany, a unique example where a result-oriented approach has been implemented. We investigated the historical evolution of the water protection programme, the result-oriented payment contracts with farmers, and farmer satisfaction with the contracts, based on interviews with the water utility and farmers as well as an analysis of the literature. Today, the water protection programme has been successfully implemented, and a significant reduction of nitrate concentration was achieved due to the following factors: (1) investment of non-negligible amounts of money for high compensation and remuneration payments, (2) different contract options, (3) farmers’ participation in the negotiation process for result-oriented payment contracts, (4) involvement of “outside” people and institutions in negotiation processes, (5) anticipation of starting a programme when nitrate levels were still far below legislative thresholds, and (6) a political and legislative framework allowing direct decisions by a water supplier. 相似文献
129.
Rui Galhano dos Santos Noemi F. Acero Sandro Matos Ricardo Carvalho Mário Vale Ana C. Marques João C. Bordado Maria M. Mateus 《Journal of Polymers and the Environment》2018,26(1):91-100
The use of petroleum-derived products should be avoided regarding the principles of green and sustainable chemistry. The work reported herein, is aimed at the liquefaction of pine shavings for the production of an environmentally-friendly polyol suitable to be used in the formulations of sprayable polyurethane foams. The biopolyols were obtained in high yield and were used to replace those derived from fossil sources, to produce more “greener” polyurethane foams and therefore, less dependent on petroleum sources, since the polyol component was substituted by products resulting from biomass liquefaction. The partial and fully exchange of the polyols was accomplished, and the results compared with a reference foam. The foams were afterward, chemical, physical, morphological, and mechanically characterized. The complete replacement of polyether polyol and polyol polyester has presented some similar characteristics as that used as a reference, validating that the path chosen for the development of more sustainable materials is on the right track for the contribution to a cleaner world. 相似文献
130.
Brownfields that are reused for the generation of renewable energy are called brightfields. This rapidly emerging idea advocates the combination sustainable site reuse and the generation of electricity from renewables. While programmes like the RE-Powering America's Land Initiative herald its benefits, academia knows but little of its barriers and challenges. This study aims to examine the technical/environmental, regulator/financial/institutional, and social barriers to this type of development, along with measures that may address them. The barriers and measures were predominately identified via a qualitative and quantitative survey sent to brightfield developers (experts), along with a review of case studies and the emerging brightfield literature. The study found that environmental/technical barriers only differ from ‘conventional’ renewable energy projects (e.g. on Greenfields) in the event of site contamination. The latter then is what makes brightfields unique and is the source for a myriad of challenges concerning risk and liability, which cause financial problems and investment hesitance. However, evidence conjectures that there is less contextual public opposition to brightfields compared to conventional renewable energy. 相似文献