全文获取类型
收费全文 | 354篇 |
免费 | 33篇 |
国内免费 | 100篇 |
专业分类
安全科学 | 39篇 |
废物处理 | 12篇 |
环保管理 | 45篇 |
综合类 | 155篇 |
基础理论 | 48篇 |
环境理论 | 6篇 |
污染及防治 | 78篇 |
评价与监测 | 12篇 |
社会与环境 | 70篇 |
灾害及防治 | 22篇 |
出版年
2023年 | 8篇 |
2022年 | 11篇 |
2021年 | 12篇 |
2020年 | 8篇 |
2019年 | 23篇 |
2018年 | 41篇 |
2017年 | 32篇 |
2016年 | 22篇 |
2015年 | 29篇 |
2014年 | 19篇 |
2013年 | 44篇 |
2012年 | 25篇 |
2011年 | 16篇 |
2010年 | 19篇 |
2009年 | 20篇 |
2008年 | 9篇 |
2007年 | 26篇 |
2006年 | 25篇 |
2005年 | 16篇 |
2004年 | 14篇 |
2003年 | 11篇 |
2002年 | 14篇 |
2001年 | 13篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1987年 | 2篇 |
1974年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有487条查询结果,搜索用时 109 毫秒
481.
482.
483.
填料-生物转盘处理有机模拟污水 总被引:2,自引:0,他引:2
针对传统生物转盘启动慢、挂膜性能差、水力停留时间长等缺点,采用英国某生物技术公司研制的新型填料复合式生物转盘处理有机模拟污水,考察水力停留时间、转盘转速、有机负荷等因素对工艺运行效果的影响。结果表明,新型生物转盘启动快,微生物相变化明显,微生物量大,挂膜效率高;抗负荷冲击能力强,有机负荷大幅度变化对其影响较小;二级转笼处有机负荷相对较低,溶解氧高,微生物的种类、数量均比一级转笼多;该转盘处理有机模拟污水的最优水力停留时间为1.5 h,最佳转速为12.4 r/min,较传统生物转盘污水处理量大,且污水COD去除率高达97%,大大降低运行能耗,出水水质达到城镇污水处理厂污染物排放标准(GB18918-2002)中的一级A标准。 相似文献
484.
Yves Pepermans Pieter Maeseele 《Environmental Communication: A Journal of Nature and Culture》2014,8(2):216-232
Starting from a risk conflicts perspective, this article challenges two common assumptions of existing research on climate change in public and media discourses. It argues that the evaluation of these discourses on the extent to which these either accurately reflect a scientific consensus or contribute to achieving social consensus insufficiently takes account of the exclusionary mechanisms it starts from. A conceptual and empirical framework is subsequently put forward which allows one to evaluate mediated discourses in terms of the extent to which democratic debate and citizenship are encouraged. Such analysis can reveal the discursive strategies underlying processes of politicization and depoliticization. This perspective is illustrated by an analysis of a local case study: the “Sing for the Climate” campaign. We conclude by calling for a broad systematic research agenda revealing the extent to which de/politicizing discourses are found to influence public and media discourses. 相似文献
485.
Ulrika Olausson Peter Berglez 《Environmental Communication: A Journal of Nature and Culture》2014,8(2):249-265
This paper suggests some further avenues of empirical and theoretical investigation for media research on climate change. “Old” suggestions, whose significance, as we see it, needs to be further reinforced, are included, as are “new” ones, which we hope will generate innovative research questions. In order to integrate the analysis with knowledge generated by media research at large, we revisit four research challenges that media scholars have long grappled with in the investigation of journalism: (1) the discursive challenge, i.e. the production, content and reception of media discourse; (2) the interdisciplinary challenge, i.e. how media research might engage in productive collaboration with other disciplines; (3) the international challenge, i.e. how to achieve a more diverse and complex understanding of news reporting globally; and (4) the practical challenge, i.e. how to reduce the theory–practice divide in media research. 相似文献
486.
This study develops a modeling approach for simulating and evaluating entrapped light nonaqueous-phase liquid (light NAPL-LNAPL) dissolution and transport of the solute in a fractured permeable aquifer (FPA). The term FPA refers to an aquifer made of porous blocks of high permeability that embed fractures. The fracture network is part of the domain characterized by high permeability and negligible storage. Previous studies show that sandstone aquifers often represent FPAs. The basic model developed in this study is a two-dimensional (2-D) model of permeable blocks that embed oblique equidistant fractures with constant aperture and orientation. According to this model, two major parameters govern NAPL dissolution and transport of the solute. These parameters are: 1) the dimensionless interphase mass transfer coefficient, K(f0), and 2) the mobility number, N(M0). These parameters represent measures of heterogeneity affecting flow, NAPL dissolution, and transport of the solute in the domain. The parameter K(f0) refers to the rate at which organic mass is transferred from the NAPL into the water phase. The parameter N(M0) represents the ratio of flow through the porous blocks to flow through the fracture network in regions free of entrapped NAPL. It also provides a measure of groundwater flow bypassing regions contaminated by entrapped NAPL. In regions contaminated by entrapped NAPL our simulations have often indicated very low permeability of the porous blocks, enabling a significant increase of the fracture flow at the expense of the permeable block flow. Two types of constitutive relationships also affect the rate of FPA cleanup: 1) the relationship between the saturation of the entrapped NAPL and the permeability of the porous blocks, and 2) the relationships representing effects of the entrapped NAPL saturation and the permeable block flow velocity on rates of interphase mass transfer. This study provides basic tools for evaluating the characteristics of pump-and-treat cleanup of FPAs by referring to sets of parameters and constitutive relationships typical of FPAs. The numerical simulations carried out in this study show that at high initial saturation of the entrapped NAPL, during initial stages of the FPA cleanup the contaminant concentration increases, but later it decreases. This phenomenon originates from significant groundwater bypassing the NAPL entrapped in the permeable blocks via the fracture network. 相似文献
487.