全文获取类型
收费全文 | 2840篇 |
免费 | 69篇 |
国内免费 | 30篇 |
专业分类
安全科学 | 149篇 |
废物处理 | 109篇 |
环保管理 | 773篇 |
综合类 | 257篇 |
基础理论 | 670篇 |
环境理论 | 2篇 |
污染及防治 | 683篇 |
评价与监测 | 170篇 |
社会与环境 | 107篇 |
灾害及防治 | 19篇 |
出版年
2023年 | 17篇 |
2022年 | 23篇 |
2021年 | 29篇 |
2020年 | 32篇 |
2019年 | 37篇 |
2018年 | 56篇 |
2017年 | 57篇 |
2016年 | 95篇 |
2015年 | 60篇 |
2014年 | 67篇 |
2013年 | 302篇 |
2012年 | 105篇 |
2011年 | 159篇 |
2010年 | 123篇 |
2009年 | 134篇 |
2008年 | 141篇 |
2007年 | 149篇 |
2006年 | 127篇 |
2005年 | 78篇 |
2004年 | 108篇 |
2003年 | 100篇 |
2002年 | 89篇 |
2001年 | 56篇 |
2000年 | 42篇 |
1999年 | 44篇 |
1998年 | 39篇 |
1997年 | 38篇 |
1996年 | 45篇 |
1995年 | 53篇 |
1994年 | 39篇 |
1993年 | 40篇 |
1992年 | 24篇 |
1991年 | 29篇 |
1990年 | 35篇 |
1989年 | 23篇 |
1988年 | 30篇 |
1987年 | 25篇 |
1986年 | 37篇 |
1985年 | 21篇 |
1984年 | 35篇 |
1983年 | 28篇 |
1982年 | 30篇 |
1981年 | 29篇 |
1980年 | 18篇 |
1979年 | 18篇 |
1978年 | 12篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1974年 | 8篇 |
1972年 | 9篇 |
排序方式: 共有2939条查询结果,搜索用时 15 毫秒
221.
222.
223.
224.
Pathogens, ammonia, odor, and greenhouse gas emissions are serious environmental concerns associated with swine production. This study was conducted in two manure pits (33,000 L each) to determine the influence of 1.5 or 3.0 g thymol L(-1) and 80 mg L(-1) urease inhibitor amendments on urea accumulation, coliform bacteria, odor, and methane emission. Each experiment lasted 18 or 19 d, during which time 30 to 36 250-mL samples (six per day) were withdrawn from underneath each pit and analyzed for urea, thymol, volatile fatty acids, coliform bacteria, and Campylobacter. At the end of each experiment, six 50-g samples from each pit were placed in serum bottles, and gas volume and composition were determined periodically for 28 d. Compared with the control pit, volatile fatty acids production was reduced 64 and 100% for the thymol amendments of 1.5 and 3.0 g L(-1), respectively. Viable coliform cells were reduced 4.68 and 5.88 log10 colony-forming units kg(-1) of slurry for the 1.5 and 3.0 g thymol L(-1), respectively, and Escherichia coli were reduced 4.67 and 5.01 log10 colony-forming units kg(-1) of slurry, respectively. Campylobacter was not detected in the pits treated with thymol, in contrast to 63% of the samples being positive for the untreated pit. Urea accumulated in the treated pits from Day 3 to 6. Total gas production from serum bottles was reduced 65 and 76% for thymol amendments of 1.5 and 3.0 g L(-1), respectively, and methane was reduced 78 and 93%, respectively. These results suggest that thymol markedly reduces pathogens, odor, and greenhouse gas emissions from a swine production facility. The urease inhibitor produced a temporary response in conserving urea. 相似文献
225.
Berry ED Woodbury BL Nienaber JA Eigenberg RA Thurston JA Wells JE 《Journal of environmental quality》2007,36(6):1873-1882
Determining the survival of zoonotic pathogens in livestock manure and runoff is critical for understanding the environmental and public health risks associated with these wastes. The occurrence and persistence of the bacterial pathogens Escherichia coli O157:H7 and Campylobacter spp. in a passive beef cattle feedlot runoff control-vegetative treatment system were examined over a 26-mo period. Incidence of the protozoans Cryptosporidium spp. and Giardia spp. was also assessed. The control system utilizes a shallow basin to collect liquid runoff and accumulate eroded solids from the pen surfaces; when an adequate liquid volume is attained, the liquid is discharged from the basin onto a 4.5-ha vegetative treatment area (VTA) of bromegrass which is harvested as hay. Basin discharge transported E. coli O157, Campylobacter spp., and generic E. coli into the VTA soil, but without additional discharge from the basin, the pathogen prevalences decreased over time. Similarly, the VTA soil concentrations of generic E. coli initially decreased rapidly, but lower residual populations persisted. Isolation of Cryptosporidium oocysts and Giardia cysts from VTA samples was infrequent, indicating differences in sedimentation and/or transport in comparison to bacteria. Isolation of generic E. coli from freshly cut hay from VTA regions that received basin discharge (12 of 30 vs. 1 of 30 control samples) provided evidence for the risk of contamination; however, neither E. coli O157 or Campylobacter spp. were recovered from the hay following baling. This work indicates that the runoff control system is effective for reducing environmental risk by containing and removing pathogens from feedlot runoff. 相似文献
226.
Christopher W. Fields-Johnson James A. Burger Daniel M. Evans Carl E. Zipper 《Environmental management》2014,53(6):1059-1065
There is renewed interest in re-establishing trees on 0.6 million ha of mining-disturbed lands in the Appalachian mountains of Eastern United States. Many coal-mined lands reclaimed to meet requirements of US federal law have thick herbaceous vegetation and compacted soils which impede tree establishment. Mitigation practices were applied on three mine sites and evaluated for success in enabling planted trees to become established. Eastern white pine (Pinus strobus), hybrid poplar (Populus deltoids × Populus trichocarpa), and mixed Appalachian hardwoods were established using weed control only and weed control with subsoil ripping. Trees were measured in October of 2008 after 5 years of growth. Subsoil ripping increased mixed hardwood survival from 43 to 71 %, hybrid poplar biomass index from 1.51 to 8.97 Mg ha?1, and Eastern white pine biomass index from 0.10 to 0.32 Mg ha?1. When restoring trees to unused mined sites, subsoil ripping can aid survival and growth to an extent that will result in a valuable forest. 相似文献
227.
de Nazelle A Nieuwenhuijsen MJ Antó JM Brauer M Briggs D Braun-Fahrlander C Cavill N Cooper AR Desqueyroux H Fruin S Hoek G Panis LI Janssen N Jerrett M Joffe M Andersen ZJ van Kempen E Kingham S Kubesch N Leyden KM Marshall JD Matamala J Mellios G Mendez M Nassif H Ogilvie D Peiró R Pérez K Rabl A Ragettli M Rodríguez D Rojas D Ruiz P Sallis JF Terwoert J Toussaint JF Tuomisto J Zuurbier M Lebret E 《Environment international》2011,37(4):766-777
228.
Nicole Shumway Megan I. Saunders Sam Nicol Richard A. Fuller Noam Ben-Moshe Takuya Iwamura Sun W. Kim Nicholas J. Murray James E. M. Watson Martine Maron 《Conservation biology》2023,37(2):e14031
Biodiversity offsets aim to counterbalance the residual impacts of development on species and ecosystems. Guidance documents explicitly recommend that biodiversity offset actions be located close to the location of impact because of higher potential for similar ecological conditions, but allowing greater spatial flexibility has been proposed. We examined the circumstances under which offsets distant from the impact location could be more likely to achieve no net loss or provide better ecological outcomes than offsets close to the impact area. We applied a graphical model for migratory shorebirds in the East Asian–Australasian Flyway as a case study to explore the problems that arise when incorporating spatial flexibility into offset planning. Spatially flexible offsets may alleviate impacts more effectively than local offsets; however, the risks involved can be substantial. For our case study, there were inadequate data to make robust conclusions about the effectiveness and equivalence of distant habitat-based offsets for migratory shorebirds. Decisions around offset placement should be driven by the potential to achieve equivalent ecological outcomes; however, when considering more distant offsets, there is a need to evaluate the likely increased risks alongside the potential benefits. Although spatially flexible offsets have the potential to provide more cost-effective biodiversity outcomes and more cobenefits, our case study showed the difficulty of demonstrating these benefits in practice and the potential risks that need to be considered to ensure effective offset placement. 相似文献
229.
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
230.
Basharat A. Pitafi James A. Roumasset 《Journal of the American Water Resources Association》2006,42(6):1441-1450
Abstract: Conserving the watershed can help to preserve ground water recharge. Preventing overuse of available water through pricing reforms can also substantially increase the value of an aquifer. Inasmuch as users are accustomed to low prices, efficiency pricing may be politically infeasible, and watershed conservation may be considered as an alternative. We estimate and compare welfare gains from pricing reform and watershed conservation for a water management district in Oahu that obtains its water supply from the Pearl Harbor aquifer. We find that pricing reform is welfare superior to watershed conservation unless the latter is able to prevent very large recharge losses. Watershed conservation that yields net gains in combination with pricing reform may cause net losses without the pricing reform. If adoption of watershed conservation delays the implementation of pricing reform, the benefits of the latter are significantly reduced. 相似文献