全文获取类型
收费全文 | 12479篇 |
免费 | 367篇 |
国内免费 | 961篇 |
专业分类
安全科学 | 343篇 |
废物处理 | 863篇 |
环保管理 | 1447篇 |
综合类 | 3035篇 |
基础理论 | 3523篇 |
污染及防治 | 2251篇 |
评价与监测 | 1182篇 |
社会与环境 | 1054篇 |
灾害及防治 | 109篇 |
出版年
2024年 | 13篇 |
2023年 | 84篇 |
2022年 | 185篇 |
2021年 | 195篇 |
2020年 | 176篇 |
2019年 | 135篇 |
2018年 | 1592篇 |
2017年 | 1540篇 |
2016年 | 1332篇 |
2015年 | 295篇 |
2014年 | 227篇 |
2013年 | 254篇 |
2012年 | 734篇 |
2011年 | 1632篇 |
2010年 | 929篇 |
2009年 | 826篇 |
2008年 | 1124篇 |
2007年 | 1435篇 |
2006年 | 180篇 |
2005年 | 145篇 |
2004年 | 117篇 |
2003年 | 137篇 |
2002年 | 159篇 |
2001年 | 59篇 |
2000年 | 62篇 |
1999年 | 49篇 |
1998年 | 38篇 |
1997年 | 23篇 |
1996年 | 21篇 |
1995年 | 22篇 |
1994年 | 16篇 |
1993年 | 16篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 12篇 |
1983年 | 8篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1935年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 656 毫秒
991.
山西旅游资源开发现状与对策研究 总被引:1,自引:0,他引:1
山西省是旅游资源大省,但其旅游收入仍处在全国的末流,因此不能被称为旅游业大省.在概述山西旅游资源的基础上,分析了其开发现状和存在问题,并针对问题从规划实施、资金引进、形象树立、可达性提高、设施完善及人员培养等方面提出了对策建议,以期指导山西省尽快发展成旅游业大省. 相似文献
992.
993.
Ongoing eutrophication is changing the Baltic Sea ecosystem. Aquaculture causes relatively small-scale nutrient emissions,
but local environmental impact may be considerable. We used substance flow analysis (SFA) to identify and quantify the most
significant flows and stocks of nitrogen (N) and phosphorus (P) related to rainbow trout aquaculture in Finland. In 2004–2007,
the input of nutrients to the system in the form of fish feed was 829 t N year−1 and 115 t P year−1. Around one-fifth of these nutrients ended up as food for human consumption. Of the primary input, 70% ended up in the Baltic
Sea, directly from aquaculture and indirectly through waste management. The nutrient cycle could be closed partially by using
local fish instead of imported fish in rainbow trout feed, thus reducing the net load of N and P to a fraction. 相似文献
994.
偕胺肟合铁(Ⅲ)纤维对α-萘酚的吸附 总被引:1,自引:0,他引:1
以腈纶纤维为原料络合Fe3+制得偕胺肟合铁(Ⅲ)纤维,用其处理α-萘酚溶液,研究了偕胺肟合铁(Ⅲ)纤维对α-萘酚的吸附工艺条件和吸附动力学参数。实验结果表明,偕胺肟合铁(Ⅲ)纤维对α-萘酚的最佳吸附工艺条件为pH=3.0、吸附温度313.15K和吸附时间45min。在最佳工艺条件下,偕胺肟合铁(Ⅲ)纤维对α-萘酚的吸附在所研究的α-萘酚浓度范围内符合Freundlich等温吸附方程。未达到饱和吸附前,偕胺肟合铁(Ⅲ)纤维对α-萘酚的吸附符合一级反应动力学特征。 相似文献
995.
During 19–20 October 2009, the Royal Swedish Academy of Sciences arranged the international symposium Energy 2050 in Stockholm. The symposium was held in association with the Swedish EU presidency in autumn 2009. Internationally renowned scientists assessed the energy issue in a broad perspective, with particular emphasis on the possibilities of a fossil-free future. The symposium focused on key topics emanating from the in-depth energy studies carried through by the Academy´s Energy Committee since 2005. The world community is facing a challenge of historic proportions to define a new energy paradigm based on fossil-energy substitutes. This article gives an overview of the current global energy situation (2007) and of the technologies which have the major potential for supplying energy up to year 2050 without jeopardizing the CO2 emission targets. 相似文献
996.
997.
Hospital wastes are infectious wastes generated in hospitals and need to be disposed in such a way that they do not spread
disease. In this experiment, 5, 10, 15 and 20% cow manure (CM) were mixed with hospital wastes (HW), and mixed wastes were
subjected to vermicomposting. In control treatment, only HW was used for vermicomposting. Results suggested that significantly
(P ≤ 0.05) higher total nitrogen content was recorded in vermicomposts when 10% or more CM was added to HW. Higher mineralization
rate (decrease in C/N ratio) and cellulase activity is probably responsible for rapid organic matter decomposition (loss of
total organic carbon). Ergosterol content i.e., total fungal biomass and cellulolytic fungal population were almost constant
initially, but increased in the latter stage of vermicomposting. All the vermicompost samples, prepared in this experiment,
showed the absence of coliform bacteria. Therefore, it could be concluded that 10% CM addition with HW was the most economical
to obtain best quality vermicompost in terms of nutrient content and microbial status. 相似文献
998.
Thuli N. Mdluli Coleen H. Vogel 《Mitigation and Adaptation Strategies for Global Change》2010,15(3):205-222
South Africa faces several development challenges including those linked to climate change. Energy usage in South Africa,
for example, is already constrained because of a range of development challenges (the dependence on cheap coal as a heating
source; energy availability; access; affordability of alternative energy sources; and a range of health impacts, including
air pollution). Notwithstanding calls for a transition to a low carbon economy, there have been few, recent assessments in
South Africa of the costs associated with such a transition, particularly the social and economic costs for the poor who use
energy in a variety of ways. In this paper we focus on trying to unravel some of the complex energy-use behaviour including
understanding what drives consumers in resource-poor areas to choose and use persistently risky energy options. Analysis of
qualitative data in two township areas, Doornkop and Kwaguqa, shows that township households, whether electrified or not,
continue to burn coal. In both study areas, an estimated 80% of electrified households burn coal for space heating and cooking
and also make use of multiple fuel sources for a range of activities. Although the major obstacles preventing people from
discontinuing domestic coal combustion are poverty, the ready availability and social acceptability of coal together with
other social customs cannot be underrated. This paper therefore highlights some of the persistent challenges associated with
sustainable energy transitions in South Africa including implications for improved mitigation and adaptation for the energy
sector in wider climate change efforts. 相似文献
999.
1000.
Tao Miaomiao Xu Ying Liu Qingyang Liu Yanju Tian Shili Schauer James J. 《Environmental Chemistry Letters》2023,21(3):1281-1286
Environmental Chemistry Letters - Plants remove efficiently atmospheric pollution by soot particles, yet the mechanisms used by leaves to capture soot particles are unclear. Here, we studied the... 相似文献