全文获取类型
收费全文 | 982篇 |
免费 | 18篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 34篇 |
废物处理 | 32篇 |
环保管理 | 173篇 |
综合类 | 114篇 |
基础理论 | 283篇 |
环境理论 | 1篇 |
污染及防治 | 253篇 |
评价与监测 | 68篇 |
社会与环境 | 43篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 27篇 |
2022年 | 32篇 |
2021年 | 14篇 |
2020年 | 12篇 |
2019年 | 29篇 |
2018年 | 23篇 |
2017年 | 33篇 |
2016年 | 39篇 |
2015年 | 25篇 |
2014年 | 42篇 |
2013年 | 84篇 |
2012年 | 35篇 |
2011年 | 81篇 |
2010年 | 52篇 |
2009年 | 42篇 |
2008年 | 46篇 |
2007年 | 55篇 |
2006年 | 59篇 |
2005年 | 32篇 |
2004年 | 32篇 |
2003年 | 35篇 |
2002年 | 33篇 |
2001年 | 19篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 11篇 |
1997年 | 14篇 |
1996年 | 15篇 |
1995年 | 6篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1976年 | 1篇 |
1965年 | 1篇 |
1941年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有1007条查询结果,搜索用时 162 毫秒
491.
Edgerton ES Hartsell BE Saylor RD Jansen JJ Hansen DA Hidy GM 《Journal of the Air & Waste Management Association (1995)》2006,56(9):1325-1341
Deployment of continuous analyzers in the Southeastern Aerosol Research and Characterization Study (SEARCH) network began in 1998 and continues today as new technologies are developed. Measurement of fine particulate matter (PM2.5) mass is performed using a dried, 30 degrees C tapered element oscillating microbalance (TEOM). TEOM measurements are complemented by observations of light scattering by nephelometry. Measurements of major constituents include: (1) SO4(2-) via reduction to SO2; (2) NH4+ and NO3- via respective catalytic oxidation and reduction to NO, (3) black carbon (BC) by optical absorption, (4) total carbon by combustion to CO2, and (5) organic carbon by difference between the latter two measurements. Several illustrative examples of continuous data from the SEARCH network are presented. A distinctive composite annual average diurnal pattern is observed for PM2.5 mass, nitrate, and BC, likely indicating the influence of traffic-related emissions, growth, and break up of the boundary layer and formation of ammonium nitrate. Examination of PM2.5 components indicates the need to better understand the continuous composition of the unmeasured "other" category, because it contributes a significant fraction to total mass during periods of high PM2.5 loading. Selected episodes are presented to illustrate applications of SEARCH data. An SO2 conversion rate of 0.2%/hr is derived from an observation of a plume from a coal-fired power plant during early spring, and the importance of local, rural sources of NH3 to the formation of ammonium nitrate in particulate matter (PM) is demonstrated. 相似文献
492.
Occurrence and degradation of butyltins and wastewater marker compounds in sediments from Barcelona harbor, Spain 总被引:1,自引:0,他引:1
Contamination of Barcelona harbor sediments was assessed by the quantitative determination of butyltins (TBT, DBT and MBT) and surfactant intermediates, namely linear alkylbenzenes (LABs) and nonylphenols (NPs), as markers of urban and industrial wastewater contamination, respectively. Degradation indexes of TBT and LABs were calculated. Tributyltin predominated in the whole area over its degradation products, ranging from 98 to 4702 ng Sn/g. These elevated concentrations reveal a persistent historical contamination and a moderate degradation (BT(deg)). Moreover, the high LAB concentrations (1.2-53.1 microg/g) compared to the relatively low NP levels (3.8-72.0 ng/g) suggest a predominance of urban over industrial wastewater inputs, although a significant correlation (r(2) = 0.82, N = 12, P = 0.001) between LABs and NPs was found. Stormwater runoff and combined sewer overflows (CSO) were likely the most possible sources for both surfactant intermediates. The high degradation index values obtained for LABs could indicate an improvement in the wastewater management reducing its recent discharge into the Barcelona harbor area. 相似文献
493.
494.
Lomesh Dutta H. Eric Nuttall Al Cunningham Garth James Randy Hiebert 《补救:环境净化治理成本、技术与工艺杂志》2005,15(4):101-111
A new use for biofilm barriers was developed and successfully applied to treat nitrate‐contaminated groundwater down to drinking water standards. The barrier was created by stimulating indigenous bacteria with injections of molasses as the carbon donor and a combination of yeast extract and trimetaphosphate as nutrients. This injection of amendments results in bacterial growth in the aquifer, which attaches to the sand grains to create a reactive semipermeable biofilm. The biofilm barrier presented in this article reduced the migration of contaminants and provided an active zone for remediation. The cylindrical biobarrier was constructed using eight wells on the perimeter forming a 60‐foot‐diameter reactive biodenitrification region. Another well at the center was installed to continuously extract the treated water. The intent was to produce a continuous source of nitrate‐free water. The system operated for over one year, and during this period, the biobarrier was revived multiple times by reinjecting molasses in the perimeter wells. Nitrate concentrations of treated water decreased from 275 mg/L (as nitrogen) to < 1 mg/L. © 2005 Wiley Periodicals, Inc. 相似文献
495.
Landsat Thematic Mapper: Detection of Shifts in Community Composition of Coral Reefs 总被引:1,自引:0,他引:1
Abstract: We assembled a time series of 20 Landsat thematic mapper images from 1982 to 1996 for Key Largo, Florida, to ascertain whether satellite imagery can detect temporal changes in coral reef communities. Selected reef and control areas were examined for changes in brightness, spectral reflectance, band ratios, spatial texture, and temporal texture ( pixel-to-pixel change over time). We compared the data to known changes in the reef ecosystem of Carysfort Reef and terrestrial sample sites. Changes in image brightness and spectral-band ratios were suggestive of shifts from coral- to algal-dominated community structure, but the trends were not statistically significant. The spatial heterogeneity of the reef community decreased in the early 1980s at scales consistent with known ecological changes to the coral community on Carysfort Reef. An analysis of pixel-scale variation through time, termed temporal texture, revealed that the shallow reef areas are the most variable in regions of the reef that have experienced significant ecological decline. Thus, the process of reef degradation, which alters both the spatial patterning and variability of pixel brightness, can be identified in unclassified thematic mapper images. 相似文献
496.
Rick D. Saylor Eric S. Edgerton Benjamin E. Hartsell Karsten Baumann D. Alan Hansen 《Atmospheric environment (Oxford, England : 1994)》2010,44(38):4994-5004
Continuous ammonia (NH3) measurements with a temporal resolution of 5 min were implemented at selected SEARCH sites in the southeastern U. S. during 2007. The SEARCH continuous NH3 instrument uses a citric acid denuder difference technique employing a dual-channel nitric oxide-ozone chemiluminescence analyzer. Data from two SEARCH sites are presented, Jefferson Street, Atlanta (JST) (urban), and Yorkville, Georgia (YRK) (rural), for the period July–December, 2007. Highest NHx (total ammonia = gaseous NH3 + PM2.5 NH4+) values were observed in August and September at both JST and YRK. Highest NH3 values occurred in August and September at JST, but in August through October at YRK. Lowest NH3 and NHx values occurred in December at both sites. YRK is significantly impacted by nearby poultry sources, routinely experiencing hourly average NH3 mixing ratios above 20 ppbv. Wind sector analysis clearly implicates the nearby poultry operations as the source of the high NH3 values. Weekday versus weekend differences in composite hourly mean diurnal profiles of NH3 at JST indicate that mobile sources have a measurable but relatively small impact on NH3 observed at that site, and little or no impact on NH3 observed at YRK. A distinctive composite mean hourly diurnal variation was observed at both JST and YRK, exhibiting maxima in the morning and evening with a broad minimum during midday. Analysis of observed NH3 diurnal variations from the literature suggests a hypothesized mechanism for the observed behavior based on interaction of local emissions and dry deposition with the formation and collapse of the dynamically mixed atmospheric boundary layer during the day and shallow nocturnal layer at night. Simple mixed layer concentration box model simulations confirm the plausibility of the suggested mechanism. 相似文献
497.
498.
499.
500.
Richard G. Ryall David Callen Robert Cocciolone Amra Duvnjak Renata Esca Niki Frantzis Elizabeth M. Gjerde Eric A. Haan Trudy Hocking Grant Sutherland David W. Thomas Fiona Webb 《黑龙江环境通报》2001,21(7):553-557
Of the 65 328 pregnancies of South Australian mothers screened by the South Australian Maternal Serum Antenatal Screening (SAMSAS) Programme between 1 January 1991 and 31 December 1997, 3431 (5.25%) were declared at increased risk of fetal Down syndrome. Fetal or neonatal karyotype was determined in 2737/3431 (79.8%) of these pregnancies, including 16 with early fetal loss. Interrogation of the database of the South Australian Neonatal Screening Service showed 643 live-born infants whose phenotype was not subsequently questioned among the 694 pregnancies whose karyotype was not determined. Of the remaining 51/3431 pregnancies, 19 ended in early fetal loss without karyotyping and no newborn screening or other records could be found for 32 cases. The 129 instances of abnormal karyotype found were Down syndrome (84), trisomy 18 (four), trisomy 13 (three), triploidy (two), female sex chromosome aneuploidy (six) and male sex chromosome aneuploidy (five), inherited balanced rearrangements (19), mosaic or de novo balanced abnormalities (four) and unbalanced karyotypes (two). In the pregnancies declared at increased risk of fetal Down syndrome, only the karyotype for Down syndrome occurred with a frequency greater than that expected for the general, pregnant population. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献