首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   158篇
  免费   4篇
  国内免费   1篇
安全科学   7篇
废物处理   6篇
环保管理   45篇
综合类   15篇
基础理论   37篇
环境理论   1篇
污染及防治   34篇
评价与监测   10篇
社会与环境   7篇
灾害及防治   1篇
  2023年   1篇
  2022年   1篇
  2021年   1篇
  2020年   1篇
  2019年   2篇
  2018年   4篇
  2017年   4篇
  2016年   4篇
  2015年   5篇
  2014年   4篇
  2013年   9篇
  2012年   9篇
  2011年   8篇
  2010年   9篇
  2009年   10篇
  2008年   11篇
  2007年   5篇
  2006年   6篇
  2005年   9篇
  2004年   5篇
  2003年   3篇
  2002年   8篇
  2001年   5篇
  2000年   3篇
  1999年   3篇
  1998年   3篇
  1997年   1篇
  1996年   6篇
  1995年   2篇
  1994年   3篇
  1991年   2篇
  1990年   1篇
  1988年   2篇
  1986年   1篇
  1985年   1篇
  1982年   2篇
  1981年   1篇
  1979年   2篇
  1978年   2篇
  1977年   2篇
  1973年   1篇
  1969年   1篇
排序方式: 共有163条查询结果,搜索用时 15 毫秒
101.
Lake eutrophication is an economic, recreational, and aesthetic problem that affects every lake of the world. Eutrophication is the natural process of lake aging, and progresses irrespective of man's activities. Pollution, however, can hasten the natural rate of aging and shorten the life expectancy of a body of water. The eutrophication of a lake consists of the gradual progression from one life stage to another based on the degree of nourishment or productivity. The extinction of a lake is attributed to enrichment by nutritive materials, biological productivity, decay, and sedimentation. Presently used methods for retarding eutrophication are the abatement of cultural enrichment, treatment of eutrophic symptoms, and control of fundamental causes.  相似文献   
102.
Environmental Science and Pollution Research - In 2008, the Mulberry River, a National Wild and Scenic River, was listed as impaired due to low pH (below pH 6.0). Over the last...  相似文献   
103.
Laboratory and field experiments were performed to evaluate integrative measurement methods for atmospheric nitrates, sulphate and sulphur dioxide. Denuder tubes and several filter media were tested under laboratory and field conditions. Effects of sampling variables such as temperature and relative humidity, flow rates, concentration, loading capacity and artifacts due to NO, NO2 and SO2 were also evaluated. The integrative filter sampling method and the ion chromatographic analytical procedure gave a measurement precision (relative standard deviation) of ±11.5 percent for particulate NO3 ? on Teflon and ±15.6 percent for gaseous HNO3 on nylon; for both these constituents, the detection limit was about 0.1 μ m?3.  相似文献   
104.
Ecosystem-based Management (EBM) is an approach that includes different management priorities and requires a balance between anthropogenic and ecological resource demands. Indicators can be used to monitor ecosystem status and trends, and assess whether projects and/or programs are leading to the achievement of management goals. As such, the careful selection of a suite of indicators is a crucial exercise. In this paper we describe an indicator evaluation and selection process designed to support the EBM approach in Puget Sound. The first step in this process was the development of a general framework for selecting indicators. The framework, designed to transparently include both scientific and policy considerations into the selection and evaluation process, was developed and then utilized in the organization and determination of a preliminary set of indicators. Next, the indicators were assessed against a set of nineteen distinct criteria that describe the model characteristics of an indicator. A literature review was performed for each indicator to determine the extent to which it satisfied each of the evaluation criteria. The result of each literature review was summarized in a numerical matrix, allowing comparison, and demonstrating the extent of scientific reliability. Finally, an approach for ranking indicators was developed to explore the effects of intended purpose on indicator selection. We identified several sets of scientifically valid and policy-relevant indicators that included metrics such as annual-7 day low flow and water system reliability, which are supportive of the EBM approach in the Puget Sound.  相似文献   
105.
Abstract

The 1,2,3,4‐tetrachloro‐7‐fluorodibenzo‐p‐dioxin has been synthesized via condensation of 4‐fluorocatechol and pentachloronitrobenzene. This compound could be used as an internal standard for the analysis of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin by Chromatographic methods.  相似文献   
106.
Following a global trend, the new policy goals emphasize the need to protect rather than to use the ability of ecosystems to recover from disturbances. This necessitates the adoption of response measurements to quantify ecological condition and monitor ecological change. Response monitoring focuses on properties that are essential to the sustainability of the ecosystem. These monitoring tools can be used to establish natural ranges of ecological change within ecosystems, as well as to quantify conceptually acceptable and unacceptable ranges of change. Through a framework of biological criteria and biological impairment standards, the results of response monitoring can become an integral part of future water resource management strategies in South Africa.  相似文献   
107.
Aldehydes are an airborne byproduct of many industrialprocesses, vehicle transportation, and emissions fromnumerous natural sources. To characterize aldehydeconcentrations in ambient air of the Savannah, Georgiaarea, air samples for 3 aldehydes (formaldehyde,acetaldehyde, and propionaldehyde) were collected atfive sites on a monthly basis over a 12-month periodfrom December of 1995 through November 1996. Four ofthe sites were in central Savannah and the fifth sitewas located in a rural area about 56 km south ofSavannah. During each 24-hr sampling episode, sampleswere collected in two 12-hr periods approximatingdaylight and nighttime hours, following U.S. EPAMethod TO-11. Formaldehyde concentrations ranged from0.17 to 6.80 g m-3, acetaldehydeconcentrations ranged from 0.07 to7.60 g m-3, and propionaldehyde levels rangedfrom 0.02 to 9.10 g m-3. On average, thefour sites in Savannah had higher aldehydeconcentrations than the rural site (2.0 versus1.2 g m-3 for formaldehyde, 2.3 versus1.7 g m-3 for acetaldehyde, and 1.2 versus1.0 g m-3 for propionaldehyde). The daytimeconcentrations for formaldehyde and acetaldehyde werehigher than the nighttime levels. The data from allthe sites were within published worldwide backgroundvalues for aldehydes.  相似文献   
108.
Summary The attraction of Old World leaf beetles in the genusAulacophora to kairomones and parakairomones which are effective lures for New WorldDiabrotica andAcalymma were investigated. Beetles captured on sticky traps baited with single and multicomponent lures were no different from the control traps for two species ofAulacophora. Yellow colored traps and squash blossoms are attractive toAulacophora beetles which detect sub-microgram quantities of cucurbitacins on silica gel. Leaf feeding behavior and flight activity data are correlated with varietal preference of threeAulacophora species. The common response byDiabrotica andAulacophora to cucurbitacins reinforces the two groups' coevolutionary association with the Cucurbitaceae. The apparent lack of a common response toCucurbita blossom volatiles suggests recent evolutionary pathways are substantially different for these two groups of beetles.  相似文献   
109.
Increased education of consumers can be an effective tool for conservation of commercially harvested marine species when product labeling is accurate and allows an informed choice. However, generic labeling (e.g., as white fish or surimi) and mislabeling of seafood prevents this and may erode consumer confidence in seafood product labels in general. We used DNA barcoding to identify the species composition of two types of convenience seafood (i.e., products processed for ease of consumption): fish fingers (long pieces of fish covered with bread crumbs or batter, n = 241) and seafood sticks (long pieces of cooked fish, n = 30). In products labeled as either white fish or surimi, four teleost species were present. Less than 1.5% of fish fingers with species-specific information were mislabeled. Results of other studies show substantially more mislabeling (e.g., >25%) of teleost products, which likely reflects the lower economic gains associated with mislabeling of convenience seafood compared with whole fillets. In addition to species identification, seafood product labels should be required to contain information about, for example, harvesting practices, and our data indicate that consumers can have reasonable confidence in the accuracy of the labels of convenience seafood and thus select brands on the basis of information about current fisheries practice.  相似文献   
110.
A method for sampling and analysis of phenolic compounds in workplace atmospheres using Amberlite XAD‐2 sorbent tubes has been laboratory and field tested. After extraction of the adsorbed phenols with methylene chloride, the concentrated extract was analyzed by capillary column gas chromatography coupled with a flame ionization detector or a mass spectrometer. For a 3L air sample, the method has a detection limit for phenol, cresols, alkyl‐substituted phenols and xylenols of 0.3 mg/m3 using gas chromatography with flame ionization detection (GC/FID) analysis and 0.07 mg/m3 using gas chromatography mass spectroscopy/selected ion monitoring GC‐MS/SIM. Evaluation tests conducted in the laboratory indicated recoveries >85% for a wide range of phenols, cresols, xylenols and other alkyl‐substituted phenols and resorcinol. Sampling conditions were established to ensure that no breakthrough occurred for a predetermined sample volume of three (3) liters even in humid atmospheres. Stability tests indicated that for storage of up to 2 weeks at 4°C, only resorcinol showed a significant reduction in sample recovery. The proposed method and NIOSH Method 3502 were compared for the determination of phenol concentrations in air samples collected at a plant processing phenolic resins. Phenol was positively identified in the XAD sample using GC‐MS/SIM and was detected at concentrations of 40–50% of the total phenols detected using NIOSH Method 3502. This difference is attributed to the airborne paniculate matter which is known to contain bisphenols that will contribute to the total phenolic content sampled in Method 3502, but not on the XAD sample.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号