全文获取类型
收费全文 | 27730篇 |
免费 | 294篇 |
国内免费 | 288篇 |
专业分类
安全科学 | 830篇 |
废物处理 | 1244篇 |
环保管理 | 3864篇 |
综合类 | 3496篇 |
基础理论 | 7820篇 |
环境理论 | 12篇 |
污染及防治 | 6998篇 |
评价与监测 | 2096篇 |
社会与环境 | 1779篇 |
灾害及防治 | 173篇 |
出版年
2023年 | 137篇 |
2022年 | 252篇 |
2021年 | 265篇 |
2020年 | 189篇 |
2019年 | 238篇 |
2018年 | 536篇 |
2017年 | 546篇 |
2016年 | 849篇 |
2015年 | 514篇 |
2014年 | 732篇 |
2013年 | 2127篇 |
2012年 | 1257篇 |
2011年 | 1325篇 |
2010年 | 1010篇 |
2009年 | 1023篇 |
2008年 | 1154篇 |
2007年 | 1261篇 |
2006年 | 1118篇 |
2005年 | 1376篇 |
2004年 | 1532篇 |
2003年 | 1342篇 |
2002年 | 836篇 |
2001年 | 1021篇 |
2000年 | 727篇 |
1999年 | 480篇 |
1998年 | 342篇 |
1997年 | 310篇 |
1996年 | 351篇 |
1995年 | 354篇 |
1994年 | 318篇 |
1993年 | 293篇 |
1992年 | 295篇 |
1991年 | 248篇 |
1990年 | 253篇 |
1989年 | 259篇 |
1988年 | 223篇 |
1987年 | 191篇 |
1986年 | 163篇 |
1985年 | 174篇 |
1984年 | 211篇 |
1983年 | 194篇 |
1982年 | 242篇 |
1981年 | 174篇 |
1980年 | 148篇 |
1979年 | 166篇 |
1978年 | 145篇 |
1977年 | 123篇 |
1976年 | 110篇 |
1975年 | 92篇 |
1974年 | 95篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
S. Alvandi W. Li M. Schönemann C. Herrmann 《International Journal of Sustainable Engineering》2016,9(6):354-362
Value stream mapping (VSM) is a well-accepted tool within lean manufacturing concept which is often used for analysing and designing the flow of materials and information required to manufacture a product. However, the analysis is static and single product oriented, which fails to cope with either the variation of production plan or a multi-product environment. In addition, the environmental impact of a manufacturing system is highly associated with the dynamic consumption of energy and resources. Despite the recent integration of VSM with simulation or environmental studies (in the domain of energy efficiency), still neglected is the dynamic assessment of all the resources involved in a multi-product production environment. This paper presents a methodology for modelling multi-product manufacturing systems with dynamic material, energy and information flows with the aim to generate economic and environmental value stream maps (E2VSM). The proposed methodology is validated with an industrial case. 相似文献
992.
A method to estimate the impact of clear-cutting on nutrient concentrations in boreal headwater streams 总被引:1,自引:0,他引:1
Large-scale forestry operations, like clear-cutting, may impair surface water quality if not done with environmental considerations in mind. Catchment and country level estimates of nutrient loads from forestry are generally based on specific export values, i.e., changes in annual exports due to the implemented forestry operations expressed in kg ha−1. We introduce here a specific concentration approach as a method to estimate the impact of clear-cutting on nutrient concentrations and export in headwater streams. This new method is potentially a more dynamic and flexible tool to estimate nutrient loads caused by forestry, because variation in annual runoff can be taken into account in load assessments. We combined water quality data from eight boreal headwater catchment pairs located in Finland and Sweden, where the effect of clear-cutting on stream water quality has been studied experimentally. Statistically significant specific concentration values could be produced for total nitrogen, nitrate, ammonium, and phosphate. The significant increases in the concentrations of these nutrients occurred between 2 and 6 years after clear-cutting. Significant specific concentration values could not be produced for total phosphorus and total organic carbon with the whole dataset, although in some single studies significant increases in their concentrations after clear-cutting were observed. The presented method enables taking into account variation in runoff, temporal dynamics of effects, and the proportional size of the treated area in load calculations. The number of existing studies considering large site-specific variation in responses to clear-cutting is small, and therefore further empirical studies are needed to improve predictive capabilities of the specific concentration values. 相似文献
993.
Anna Maria J?nsson Olle Anderbrant Jennie Holmér Jacob Johansson Guy Schurgers Glenn P. Svensson Henrik G. Smith 《Ambio》2015,44(3):249-255
In recent years, climate impact assessments of relevance to the agricultural and forestry sectors have received considerable attention. Current ecosystem models commonly capture the effect of a warmer climate on biomass production, but they rarely sufficiently capture potential losses caused by pests, pathogens and extreme weather events. In addition, alternative management regimes may not be integrated in the models. A way to improve the quality of climate impact assessments is to increase the science–stakeholder collaboration, and in a two-way dialog link empirical experience and impact modelling with policy and strategies for sustainable management. In this paper we give a brief overview of different ecosystem modelling methods, discuss how to include ecological and management aspects, and highlight the importance of science–stakeholder communication. By this, we hope to stimulate a discussion among the science–stakeholder communities on how to quantify the potential for climate change adaptation by improving the realism in the models. 相似文献
994.
Identification of vulnerable arable areas to phosphorus (P) losses is needed to effectively implement mitigation measures. Indicators for source (soil test P, STP), potential mobilization by erosion (soil dispersion), and transport (unit-stream power length-slope, LS) risks were used to screen the vulnerability to suspended solids (SS) and P losses in two contrasting catchments regarding topography, soil textural distribution, and STP. Soils in the first catchment ranged from loamy sand to clay loam, while clay soils were dominant in the second catchment. Long-term SS and total P losses were higher in the second catchment in spite of significantly lower topsoil STP. A higher proportion of areas in the second catchment were identified with higher risk due to the significantly higher risk of overland flow generation (LS) and a significantly higher mobilization risk in the soil dispersion laboratory tests. A simple screening method was presented to improve the placement of mitigation measures. 相似文献
995.
996.
近年来,全氟化合物(PFCs)如全氟辛烷磺酸(PFOS)和全氟辛酸(PFOA,其分子结构如图1所示)已经被明确为持久性有机污染物(POPs),并在环境中普遍存在[1].由于PFCs可能具有毒性和生物积聚性,因此,对食品、饮用水、组织、血浆和全血中PFCs分析方法的建立受到越来越多的关注. 相似文献
997.
Canhada João C. S. Paiva Fábio F. G. Shinohara Gabriel M. M. Okimoto Fernando Hiranobe Carlos T. Teixeira Silvio R. Job Aldo E. Santos Renivaldo J. 《Journal of Material Cycles and Waste Management》2023,25(2):944-953
Journal of Material Cycles and Waste Management - Leather production is a technology that boosts the economy because of its versatility and durability. However, the wastes generated throughout the... 相似文献
998.
Lunag Marcelino N. Abana Alexander S. Agcaoili Juco P. Arellano Jillien Kaith T. Caluza Coleen Angela G. Decena Nick Brylle V. Paz Emmanuel R. Dela Delgado Lyka Angela B. Obero Aaron F. Ocampo Don Miguel E. Sacdalan Charlene Ann D. 《Journal of Material Cycles and Waste Management》2023,25(2):1216-1226
Journal of Material Cycles and Waste Management - The daily use of facemask to prevent virus transmission increases the negative effect on the environment because of improper waste disposal. Due to... 相似文献
999.
Maia Lana S. Balieiro Lorena C. S. Teixeira Ericson J. O. Rodrigues Luciano M. Rosa Derval S. Mulinari Daniella R. 《Journal of Material Cycles and Waste Management》2023,25(4):2295-2311
Journal of Material Cycles and Waste Management - The use of lignocellulosic fibers as fillers in polymer matrices has aroused the interest of the scientific community and industrial sectors. In... 相似文献
1000.
Sarkar Sayantan Datta Deepshikha Deepak K. S. Mondal Bikash Kumar Das Bimal 《Journal of Material Cycles and Waste Management》2023,25(4):1935-1965
Journal of Material Cycles and Waste Management - Waste lubricating oil is considered to be a hazardous waste and has tremendous impact on human health and environment. The present review... 相似文献