全文获取类型
收费全文 | 39569篇 |
免费 | 339篇 |
国内免费 | 249篇 |
专业分类
安全科学 | 1030篇 |
废物处理 | 2225篇 |
环保管理 | 5134篇 |
综合类 | 5427篇 |
基础理论 | 10844篇 |
环境理论 | 8篇 |
污染及防治 | 9023篇 |
评价与监测 | 3084篇 |
社会与环境 | 3200篇 |
灾害及防治 | 182篇 |
出版年
2023年 | 134篇 |
2022年 | 266篇 |
2021年 | 330篇 |
2020年 | 203篇 |
2019年 | 251篇 |
2018年 | 1862篇 |
2017年 | 1795篇 |
2016年 | 1877篇 |
2015年 | 647篇 |
2014年 | 886篇 |
2013年 | 2486篇 |
2012年 | 1481篇 |
2011年 | 2638篇 |
2010年 | 1836篇 |
2009年 | 1740篇 |
2008年 | 2293篇 |
2007年 | 2543篇 |
2006年 | 1217篇 |
2005年 | 1145篇 |
2004年 | 1080篇 |
2003年 | 1122篇 |
2002年 | 1107篇 |
2001年 | 1116篇 |
2000年 | 781篇 |
1999年 | 490篇 |
1998年 | 384篇 |
1997年 | 384篇 |
1996年 | 397篇 |
1995年 | 466篇 |
1994年 | 397篇 |
1993年 | 345篇 |
1992年 | 379篇 |
1991年 | 356篇 |
1990年 | 328篇 |
1989年 | 324篇 |
1988年 | 296篇 |
1987年 | 241篇 |
1986年 | 247篇 |
1985年 | 247篇 |
1984年 | 284篇 |
1983年 | 264篇 |
1982年 | 273篇 |
1981年 | 221篇 |
1980年 | 165篇 |
1979年 | 181篇 |
1978年 | 162篇 |
1977年 | 133篇 |
1975年 | 138篇 |
1973年 | 167篇 |
1972年 | 142篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
851.
Jung-Kwang Kim Sun-Kee Han Geon-Ha Kim Ji-Tae Kim Chae-Young Lee 《Journal of Material Cycles and Waste Management》2017,19(1):118-123
This study was aimed to investigate the biodegradation characteristics of organic matters in swine carcasses. The lysimeters were simulated with different initial operating conditions: 30 % volumetric moisture content and no sludge addition for lysimeter A (control), 30 % volumetric moisture content and anaerobic sludge addition for lysimeter B, and 40 % volumetric moisture content and anaerobic sludge addition for lysimeter C. The degradation efficiency (18.4 %) of lysimeter B was higher than that (15.2 %) of lysimeter A due to anaerobic sludge addition. Lysimeter B showed higher CH4 yield (15.6 L/kg VS) and CH4 production rate (0.41 L/kg VS days) compared to lysimeter A by 31 % and 14 %, respectively. In addition, the degradation efficiency improved from 18.4 % (lysimeter B) to 26.3 % (lysimeter C) by increasing volumetric moisture content. The CH4 yield (22.9 L/kg VS) and CH4 production rate (0.68 L/kg VS days) of lysimeter C were higher than those of lysimeter B, respectively. Total organic carbon (TOC) removed in lysimeter C was converted to leachate (20.3 %) and gas (6.0 %), whose values were higher than those of lysimeter A and B. These results demonstrated that the proper control of initial operating conditions could accelerate the anaerobic degradation of organic matters in swine carcasses. 相似文献
852.
853.
The addition of lipid wastes to the digestion of swine manure was studied as a means of increasing biogas production. Lipid waste was obtained from a biodiesel plant where used cooking oil is the feedstock. Digestion of this co-substrate was proposed as a way of valorising residual streams from the process of biodiesel production and to integrate the digestion process into the biorefinery concept.Batch digestion tests were performed at different co-digesting proportions obtaining as a result an increase in biogas production with the increase in the amount of co-substrate added to the mixture. Semi-continuous digestion was studied at a 7% (w/w) mass fraction of total solids. Co-digestion was successful at a hydraulic retention time (HRT) of 50 d but a decrease to 30 d resulted in a decrease in specific gas production and accumulation of volatile and long chain fatty acids. The CH4 yield obtained was 326 ± 46 l/kg VSfeed at an HRT of 50 d, while this value was reduced to 274 ± 43 l/kg VSfeed when evaluated at an HRT of 30 d. However these values were higher than the one obtained under batch conditions (266 ± 40 l/kg VSfeed), thus indicating the need of acclimation to the co-substrate. Despite of operating at low organic loading rate (OLR), measurements from respirometry assays of digestate samples (at an HRT of 50 d) suggested that the effluent could not be directly applied to the soil as fertiliser and might have a negative effect over soil or crops. 相似文献
854.
Roger A. Baldwin Niamh Quinn David H. Davis Richard M. Engeman 《Environmental science and pollution research international》2014,21(9):5795-5802
Roof rats (Rattus rattus) and deer mice (Peromyscus maniculatus) are occasional pests of nut and tree fruit orchards throughout California and in many other parts of the USA and beyond. In general, the most practical and cost-effective control method for rodents in many agricultural environments is the use of rodenticides (toxic baits), but little or no information exists on the efficacy of current rodenticides in controlling roof rats and deer mice in orchards. Therefore, our goals were to develop an index of rodent activity to monitor efficacy of rodenticides and to subsequently test the efficacy of three California Department of Food and Agriculture rodenticide baits (0.005 % chlorophacinone treated oats, 0.005 % diphacinone treated oats, and 0.005 % diphacinone wax block) to determine their utility for controlling roof rats and deer mice in agricultural orchards. We determined that a general index using the number of roof rat photos taken at a minimum of a 5-min interval was strongly correlated to the minimum number known estimate of roof rats; this approach was used to monitor roof rat and deer mouse populations pre- and post-treatment. Of the baits tested, the 0.005 % diphacinone treated oats was most effective for both species; 0.005 % chlorophacinone grain was completely ineffective against roof rats. Our use of elevated bait stations proved effective at providing bait to target species and should substantially limit access to rodenticides by many non-target species. 相似文献
855.
Journal of Polymers and the Environment - To optimize the phase separation temperature of poly (N-isopropylacrylamide) two monomers have been used to fabricate a series of three functional and... 相似文献
856.
857.
858.
Á. Pereira A. Carballo-Penela A. Guerra X. Vence 《Journal of Environmental Planning and Management》2018,61(2):348-369
The servicising approach in vineyard protection is considered a valid alternative to achieve decoupling between the economic and environmental performance of viticulture. In this paper, a policy package is designed to promote the uptake of a servicised model of vineyard protection in an area of smallholding viticulture. In doing so, a specific methodology based on a step by step protocol has been followed that aims to come up with a package that is effective, implementable and socially as well as politically acceptable. The paper concludes on the importance of combining several policy instruments in a policy package to realise the political objective. The proposed viable policy package includes incentives that support the companies’ shift towards offering crop protection solutions, further development of IPM solutions and instruments that encourage farmers to reduce the use of pesticides and collectively hire crop protection services. 相似文献
859.
Russian Journal of Ecology - Abstract—Long-term observations (1968–2019) on the dynamics of infection by the cestode Eubothrium rugosum in the burbot (Lota lota) have been performed in... 相似文献
860.
Koebele Elizabeth A. Crow Deserai A. Albright Elizabeth A. 《Environmental management》2020,65(1):1-18
The 17 Sustainable Development Goals (SDGs) underpinned by 169 targets presents national governments with huge challenges for implementation. We developed a proposal for a National Blueprint Framework (NBF) with 24 water-related indicators, centered on SDG 6 (clean water and sanitation for all), each with a specific target. We applied the NBF to 28 EU Member States (EU-28) and conclude that: 相似文献