全文获取类型
收费全文 | 298篇 |
免费 | 12篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 14篇 |
废物处理 | 5篇 |
环保管理 | 52篇 |
综合类 | 38篇 |
基础理论 | 70篇 |
污染及防治 | 114篇 |
评价与监测 | 14篇 |
社会与环境 | 8篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 8篇 |
2018年 | 13篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 5篇 |
2014年 | 1篇 |
2013年 | 40篇 |
2012年 | 10篇 |
2011年 | 17篇 |
2010年 | 10篇 |
2009年 | 17篇 |
2008年 | 8篇 |
2007年 | 14篇 |
2006年 | 15篇 |
2005年 | 13篇 |
2004年 | 7篇 |
2003年 | 13篇 |
2002年 | 19篇 |
2001年 | 18篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 5篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1974年 | 2篇 |
1967年 | 1篇 |
1964年 | 1篇 |
1954年 | 1篇 |
1919年 | 4篇 |
1918年 | 1篇 |
1913年 | 3篇 |
排序方式: 共有316条查询结果,搜索用时 15 毫秒
221.
Engelbrecht JP Swanepoel L Chow JC Watson JG Egami RT 《Environmental monitoring and assessment》2001,69(1):1-15
This article presents results from the particulate monitoringcampaign conducted at Qalabotjha in South Africa during the winter of 1997. Combustion of D-grade domestic coal and low-smoke fuels were compared in a residential neighborhood to evaluate the extent of air quality improvement by switchinghousehold cooking and heating fuels.Comparisons are drawn between the gravimetric results from the two types of filter substrates (Teflon-membrane and quartz-fiber) as well as between the integrated and continuous samplers. It is demonstrated that the quartz-fiber filters reported 5 to 10% greater particulate mass than the Teflon-membrane filters, mainly due to the adsorption of organic gases onto the quartz-fiber filters. Due to heating of sampling stream to 50 °C in the TEOM continuous sampler and the high volatile content of the samples, approximately 15% of the particulate mass was lost during sampling.The USEPA 24-hr PM2.5 and PM10 National Ambient Air Quality Standards (NAAQS) of 65 g m-3 and 150 g m-3, respectively, were exceeded on several occasions during the 30-day field campaign. Average PMconcentrations are highest when D-grade domestic coal was used, and lowest between day 11 and day 20 of the experiment when a majority of the low-smoke fuels were phased in. Source impacts from residential coal combustion are also found to be influenced by changes in meteorology, especially wind velocity.PM2.5 and PM10 mass, elements, water-soluble cations (sodium, potassium, and ammonium), anions (chloride, nitrate, and sulfate), as well as organic and elemental carbonwere measured on 15 selected days during the field campaign. PM2.5 constituted more than 85% of PM10 at three Qalabotjha residential sites, and more than 70% of PM10 at the gradient site in the adjacent community of Villiers. Carbonaceous aerosol is by far the most abundant component, accounting for more than half of PM mass at the three Qalabotjha sites, and for more than a third of PM mass at the gradient site. Secondary aerosols such as sulfate, nitrate,and ammonium are also significant, constituting 8 to 12% of PM mass at the three Qalabotjha sites and 15 to 20% at the Villiers gradient site. 相似文献
222.
Alan W. Gertler William G. Coulombe John G. Watson John L. Bowen Richard T. Egami Stan Marsh 《Environmental monitoring and assessment》1993,24(1):13-25
The USEPA replaced TSP with PM10 as the National Ambient Air Quality Standard for particulate matter. The commercially available PM10 sampler is a high-volume model using quartz fiber filters. In certain investigations, such as source apportionment studies, chemical analysis of the filter is necessary, however, many analyses cannot be run on quartz filters. An alternate filter such as Teflon is amenable to XRF and ion chemical analyses but is not amenable to analysis for carbon. To overcome these problems DRI constructed a medium-volume PM10 sampler that is capable of collecting particulates on both Teflon and quartz fiber filters simultaneously. This paper describes the design of the DRI medium-volume PM10 sampler, discusses a method for determining equivalence of two samplers, the results of applying the method to test the equivalence of the medium-volume sampler and a commerical high-volume sampler, and examines differences between PM10 and TSP measurements in a southwestern desert. 相似文献
223.
224.
Two balanced reciprocal translocations were found in an amniotic fluid cell culture undertaken because of maternal age. One translocation had been inherited from each parent. Both translocations were traced through three generations of each family. The importance of banding techniques in diagnostic cytogenetics is stressed. 相似文献
225.
Dr Simon E. Meagher Nicholas M. Fisk Jonathan G. Harvey Geoffrey F. Watson Antheunis Boogert 《黑龙江环境通报》1993,13(6):495-501
Congenital bronchopulmonary malformations detectable on prenatal ultrasound include cystic adenomatoid malformation (CAM), lobar sequestration, and upper airway atresia. We describe three fetuses with prenatally detected intrathoracic lesions in which the associated pulmonary hyperechogenicity disappeared before delivery. In the first case of pulmonary sequestration, the infant was asymptomatic after birth. However, in a case of CAM and another with laryngeal atresia, respiratory distress developed after delivery, despite recent scans showing apparently normal lung fields. This experience suggests that ultrasonic resolution of hyperechogenic lung lesions in utero does not necessarily indicate resolution of the underlying pathology. 相似文献
226.
Complete laryngeal atresia is a rare congenital malformation that is known to cause hypertrophy of the fetal lung in utero. A fetus with laryngeal atresia was found to have markedly immature amniotic fluid lung maturity studies at term. Inappropriately low amniotic fluid lung maturity studies may be an important clue to the diagnosis of this condition. 相似文献
227.
228.
229.
Billy E. Johnson Pierre Y Julien Darcy K Molnar Chester C. Watson 《Journal of the American Water Resources Association》2000,36(1):31-42
ABSTRACT: The two‐dimensional soil erosion model CASC2D‐SED simulates the dynamics of upland erosion during single rainstorms. The model is based on the raster‐based surface runoff calculations from CASC2D. Rainfall precipitation is distributed in time and space. Infiltration is calculated from the Green‐Ampt equations. Surface runoff is calculated from the diffusive wave approximation to the Saint‐Venant equations in two‐dimensions. Watershed data bases in raster Geographical Information System (GIS) provide information on the soil type, size fractions, soil erodibility, cropping management, and conservation practice factors for soil erosion calculations. Upland sediment transport is calculated for the size fractions (sand, silt, and clay), and the model displays the sediment flux, the amount of suspended sediment, and the net erosion and deposition using color graphics. The model has been tested on Goodwin Creek, Mississippi. The peak discharge and time to peak are within ± 20 percent and sediment transport rates within ?50 percent to 200 percent. 相似文献
230.