全文获取类型
收费全文 | 6602篇 |
免费 | 512篇 |
国内免费 | 2173篇 |
专业分类
安全科学 | 484篇 |
废物处理 | 163篇 |
环保管理 | 1222篇 |
综合类 | 4565篇 |
基础理论 | 705篇 |
环境理论 | 2篇 |
污染及防治 | 1160篇 |
评价与监测 | 634篇 |
社会与环境 | 300篇 |
灾害及防治 | 52篇 |
出版年
2024年 | 11篇 |
2023年 | 92篇 |
2022年 | 176篇 |
2021年 | 249篇 |
2020年 | 275篇 |
2019年 | 262篇 |
2018年 | 214篇 |
2017年 | 273篇 |
2016年 | 363篇 |
2015年 | 387篇 |
2014年 | 442篇 |
2013年 | 528篇 |
2012年 | 545篇 |
2011年 | 633篇 |
2010年 | 388篇 |
2009年 | 575篇 |
2008年 | 412篇 |
2007年 | 555篇 |
2006年 | 466篇 |
2005年 | 339篇 |
2004年 | 277篇 |
2003年 | 307篇 |
2002年 | 224篇 |
2001年 | 190篇 |
2000年 | 188篇 |
1999年 | 165篇 |
1998年 | 125篇 |
1997年 | 102篇 |
1996年 | 67篇 |
1995年 | 86篇 |
1994年 | 87篇 |
1993年 | 60篇 |
1992年 | 43篇 |
1991年 | 26篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 15篇 |
1987年 | 10篇 |
1986年 | 16篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1971年 | 4篇 |
排序方式: 共有9287条查询结果,搜索用时 296 毫秒
951.
It has been postulated that road deicing salts are sufficiently diluted by spring rains to ameliorate any physiological impacts to amphibians breeding in wetlands near roads. We tested this conjecture by exposing clutches of the spotted salamander (Ambystoma maculatum) to three chloride concentrations (1 mg/L, 145 mg/L, 945 mg/L) for nine days, then transferred clutches to control water for nine days, and measured change in mass at three-day intervals. We measured mass change because water uptake by clutches reduces risks to embryos associated with freezing, predation, and disease. Clutches in controls sequestered water asymptotically. Those in the moderate concentrations lost 18% mass initially and regained 14% after transfer to control water. Clutches in high concentration lost 33% mass and then lost an additional 8% after transfer. Our results suggest that spring rains do not ameliorate the effects of deicing salts in wetlands with extremely high chloride concentrations. 相似文献
952.
953.
阳澄湖浮游藻类现状调查及水质评价 总被引:1,自引:0,他引:1
对苏州阳澄湖2009年-2011年的浮游藻类现状进行调查,采用硅藻指数和Shannon-wiener指数两种生物学指数评价阳澄湖水体污染状况.结果表明,在阳澄湖发现浮游藻类219种(包括变种),秋季的浮游藻类种类数多于春季;阳澄湖水质尚好,东湖南富营养化程度较为严重.目前阳澄湖的有机污染处于缓慢上升的态势,富营养化水平也不断提高. 相似文献
954.
Per Angelstam Kjell Andersson Maths Isacson Dmitri V. Gavrilov Robert Axelsson Mattias Bäckström Erik Degerman Marine Elbakidze Elena Yu. Kazakova-Apkarimova Lotta Sartz Stefan Sädbom Johan Törnblom 《Ambio》2013,42(2):146-159
Barriers and bridges to implement policies about sustainable development and sustainability commonly depend on the past development of social–ecological systems. Production of metals required integration of use of ore, streams for energy, and wood for bioenergy and construction, as well as of multiple societal actors. Focusing on the Swedish Bergslagen region as a case study we (1) describe the phases of natural resource use triggered by metallurgy, (2) the location and spatial extent of 22 definitions of Bergslagen divided into four zones as a proxy of cumulative pressure on landscapes, and (3) analyze the consequences for natural capital and society. We found clear gradients in industrial activity, stream alteration, and amount of natural forest from the core to the periphery of Bergslagen. Additionally, the legacy of top-down governance is linked to today’s poorly diversified business sector and thus municipal vulnerability. Comparing the Bergslagen case study with other similar regions in Russia and Germany, we discuss the usefulness of multiple case studies. 相似文献
955.
在以焦炭为填料的生物滴滤塔对挥发性脂肪酸臭气的处理研究中考察了空床停留时间、臭气浓度、体积负荷以及进气温度等参数对净化效果的影响。结果表明,空床停留时间较长时对臭气降解有利。在停留时间超过97 s时,能实现完全降解;此外,净化率随臭气浓度和体积负荷的不断增加呈先增加后降低的趋势。当臭气浓度为24.29 mg/m3即臭气的体积负荷为3 g/(m3·h)时,去除率约为96%;当臭气浓度增至1 345.74 mg/m3即体积负荷增至18 g/(m3·h),去除率达100%;然而,当臭气浓度增至4 934.38 mg/m3即体积负荷增至66 g/(m3·h)时,去除率降至73.1%。另外,进气温度对净化率也有一定程度影响。当进气温度较低时,净化效率相对较高。 相似文献
956.
957.
958.
Gao J Powers K Wang Y Zhou H Roberts SM Moudgil BM Koopman B Barber DS 《Chemosphere》2012,89(1):96-101
Adsorption of natural organic matter (NOM) on nanoparticles can have dramatic impacts on particle dispersion resulting in altered fate and transport as well as bioavailability and toxicity. In this study, the adsorption of Suwannee River humic acid (SRHA) on silver nanoparticles (nano-Ag) was determined and showed a Langmuir adsorption at pH 7 with an adsorption maximum of 28.6 mg g−1 nano-Ag. It was also revealed that addition of <10 mg L−1 total organic carbon (TOC) increased the total Ag content suspended in the aquatic system, likely due to increased dispersion. Total silver content decreased with concentrations of NOM greater than 10 mg TOC L−1 indicating an increase in nanoparticle agglomeration and settling above this concentration. However, SRHA did not have any significant effect on the equilibrium concentration of ionic Ag dissolved in solution. Exposure of Daphnia to nano-Ag particles (50 μg L−1 and pH 7) produced a linear decrease in toxicity with increasing NOM. These results clearly indicate the importance of water chemistry on the fate and toxicity of nanoparticulates. 相似文献
959.
960.