全文获取类型
收费全文 | 28725篇 |
免费 | 278篇 |
国内免费 | 237篇 |
专业分类
安全科学 | 663篇 |
废物处理 | 1170篇 |
环保管理 | 3440篇 |
综合类 | 5693篇 |
基础理论 | 7228篇 |
环境理论 | 10篇 |
污染及防治 | 7229篇 |
评价与监测 | 1891篇 |
社会与环境 | 1783篇 |
灾害及防治 | 133篇 |
出版年
2022年 | 219篇 |
2021年 | 208篇 |
2019年 | 198篇 |
2018年 | 365篇 |
2017年 | 393篇 |
2016年 | 592篇 |
2015年 | 468篇 |
2014年 | 717篇 |
2013年 | 2125篇 |
2012年 | 828篇 |
2011年 | 1177篇 |
2010年 | 986篇 |
2009年 | 1023篇 |
2008年 | 1185篇 |
2007年 | 1249篇 |
2006年 | 1091篇 |
2005年 | 922篇 |
2004年 | 932篇 |
2003年 | 927篇 |
2002年 | 876篇 |
2001年 | 1122篇 |
2000年 | 766篇 |
1999年 | 498篇 |
1998年 | 325篇 |
1997年 | 372篇 |
1996年 | 384篇 |
1995年 | 413篇 |
1994年 | 416篇 |
1993年 | 361篇 |
1992年 | 366篇 |
1991年 | 359篇 |
1990年 | 359篇 |
1989年 | 335篇 |
1988年 | 293篇 |
1987年 | 286篇 |
1986年 | 276篇 |
1985年 | 280篇 |
1984年 | 295篇 |
1983年 | 286篇 |
1982年 | 276篇 |
1981年 | 247篇 |
1980年 | 230篇 |
1979年 | 231篇 |
1978年 | 207篇 |
1977年 | 212篇 |
1976年 | 165篇 |
1975年 | 175篇 |
1974年 | 193篇 |
1973年 | 175篇 |
1972年 | 164篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
321.
Incineration of municipal refuse results in the production of massive quantities of fly ash and bottom ash. Toxic elements in the original refuse may be concentrated up to 40-fold in the resultant ash. There is concern that burial of such ash in landfills could result in leaching of these elements downward into groundwater. In this study, refuse ashes were incorporated into glass, ceramic and cement composites to immobilize such toxic elements. The EP Toxicity Test (1986) was used to show that extraction of such elements by simulated acid rain is effectively blocked in these new solid materials. 相似文献
322.
Mixed primary sewage sludge was incubated anaerobically with and without azide addition to prevent biological activity. The behaviour of 1,3-, 1,4- and 1,2-dichlorobenzene, 1,3,5-, 1,2,4- and 1,2,3-trichlorobenzene, 1,2,3,4- and 1,2,4,5-tetrachlorobenzene, hexachlorobenzene, and cis- and trans-permethrin was examined to determine their potential removal during anaerobic digestion. All the chlorobenzenes were removed to varying extents over 32 days of incubation, ranging from 25% removal for 1,3,5-trichlorobenzene to 80% removal for 1,4-dichlorobenzene. Biodegradation may have been responsible for the reductions in 1,3- and 1,4-dichlorobenzene and 1,2,4- and 1,2,3-trichlorobenzene as there was no significant removal of these compounds in azide treated sludge. The removal over 32 days of cis- and transpermethrin was 87% and 96% respectively. These removals were attributed to a chemical or physical process. 相似文献
323.
Kaushik CP 《Environmental pollution (Barking, Essex : 1987)》1989,59(3):253-264
The loss of HCH (hexachlorocyclohexane) at an application rate of 25 kg ha(-1) was studied under field conditions from two surface soil layers, each of 7.5 cm, at two sites in Delhi. The soil at both sites was sandy loam type, with a pH of 8.2, and 0.8 to 1.0% organic matter content. At site 1, which was kept fallow and not watered, the upper 7.5-cm layer of soil initially lost HCH more rapidly than the lower layer. The half-life of the HCH in the upper and lower 7.5-cm layers was 21 and 41 days, respectively, and it was 26 days for the total HCH in the combined 15-cm soil layer. At site 2, which contained ornamental plants and was watered regularly, there was not much difference in the loss of HCH between the upper and lower layers. The half-life of HCH was 17 and 25 days for the upper and lower 7.5-cm layers, respectively, and it was 20 days for the total 15-cm soil layer, at this site. The loss was greatest initially at the sites, and was faster in wet soil than in dry soil. 相似文献
324.
Rowland-Bamford AJ Coghlan S Lea PJ 《Environmental pollution (Barking, Essex : 1987)》1989,59(2):129-140
Spring barley (Hordeum vulgare cv. Klaxon) plants, 9 days old, were exposed to 0.05, 0.10 or 0.15 microl litre(-1) ozone (O3) for 12 days. Fumigation was administered for 7 h between 9.00 h and 16.00 h each day. Using conventional IRGA equipment, the carbon dioxide exchange rate (CER) was shown to decrease with increasing concentration of O3 during the exposure period, falling to 60% of the control value at the highest O3 concentration. Transpiration rates and stomatal conductance showed similar trends. Light saturation curves, obtained using a leaf disc oxygen electrode, demonstrated that O3-treated leaves had lower apparent quantum yields (QY) and generally lower rates of O2 evolution at saturating light and CO2 levels. Oscillations in chlorophyll a fluorescence, normally observed in control plants, could not be detected after O3 treatment and could only be restored to some extent by feeding the phosphate sequestering agent D-mannose to the leaves. 相似文献
325.
Dollard GJ Sandalls FJ Derwent RG 《Environmental pollution (Barking, Essex : 1987)》1989,58(2-3):115-124
Simultaneous measurements of gaseous hydrogen peroxide and ozone made in southern England are reported. The hydrogen peroxide measurements are the first reported for the United Kingdom and show clear diurnal trends and correlate with ozone measurements. Measurements were made during a photochemical episode when a peak hydrogen peroxide concentration of 2.5 microg m(-3) was recorded with a simultaneous peak of 168 microg m(-3) in the ozone concentration. From observations on the rate of decay in the measured concentrations, an evening-time deposition velocity of 0.28 cm s(-1) was derived for hydrogen peroxide. 相似文献
326.
Temple PJ 《Environmental pollution (Barking, Essex : 1987)》1989,57(1):35-47
Joshua Tree National Monument (JOTR) is located about 100 km east of the Los Angeles Basin, site of the heaviest concentration of photochemical oxidant (O(3)) air pollution in the US. This investigation was conducted to measure O(3) concentrations in JOTR and to determine the effects of O(3) on vegetation in the park. Potentially phytotoxic concentrations of O(3) were recorded in JOTR in 1984 and 1985, but peak concentration occurred at night, when most plant species would be less sensitive to O(3). No O(3) effects were observed on permanent vegetation observation plots in JOTR in 1984 or 1985. Controlled exposures of native summer annual and woody perennial species to O(3) showed that most did not develop visible O(3) injury symptoms except at concentrations higher than those expected in the park. However, Rhus trilobata Nutt. was injured at 0.10 ppm O(3), 4 h per day for 4 days. This species would be a useful bioindicator to assess the effects of O(3) on native desert plants. 相似文献
327.
Musselman RC McCool PM Younglove T 《Environmental pollution (Barking, Essex : 1987)》1988,53(1-4):63-78
Numerous ozone exposure statistics were calculated using hourly ozone data from crop yield loss experiments previously conducted for alfalfa, fresh market and processing tomatoes, cotton, and dry beans in an ambient ozone gradient near Los Angeles, California. Exposure statistics examined included peak (maximum daily hourly) and mean concentrations above specific threshold levels, and concentrations during specific time periods of the day. Peak and mean statistics weighted for ozone concentration and time period statistics weighted for hour of the day were also determined. Polynomial regression analysis was used to relate each of 163 ozone statistics to crop yield. Performance of the various statistics was rated by comparing residual mean square (RMS) values. The analyses demonstrated that no single statistic was best for all crop species. Ozone statistics with a threshold level performed well for most crops, but optimum threshold level was dependent upon crop species and varied with the particular statistics calculated. The data indicated that daily hours of exposure above a critical high-concentration threshold related well to crop yield for alfalfa, market tomatoes, and dry beans. The best statistic for cotton yield was an average of all daily peak ozone concentrations. Several different types of ozone statistics performed similarly for processing tomatoes. These analyses suggest that several ozone summary statistics should be examined in assessing the relationship of ambient ozone exposure to crop yield. Where no clear statistical preference is indicated among several statistics, those most biologically relevant should be selected. 相似文献
328.
Copper sulphate has an adverse effect on some biochemical parameters of trout Salmo gairdneri. The main targets of damage are: (a)Tissue necrosis as demonstrated by increased ASAT and ALAT levels in blood plasma. (b)Inhibition of acetylcholinesterase activity. There is also a general stress effect as reflected by an elevated blood glucose level. 相似文献
329.
330.
Even in the absence of mobilization of dense nonaqueous phase liquid (DNAPL), the microemulsion that forms when the surfactant solubilizes a dense contaminant such as trichloroethylene will be more dense than water and tends to migrate downward. This paper addresses the issue of migration with a new concept: surfactant enhanced aquifer remediation at neutral buoyancy. Laboratory results of surfactant remediation in two-dimensional model aquifers show that downward migration of microemulsion containing solubilized dense contaminants can be reduced to an acceptable level, even in the absence of capillary barriers in the aquifer. One model experiment was designed to exhibit a small degree of vertical migration and full capture of the microemulsion at the extraction well. The second experiment was designed to demonstrate the effect of large buoyancy forces that lead to excessive downward migration of the microemulsion. Density measurements of aqueous solutions containing sodium dihexyl sulfosuccinate surfactant, isopropanol, trichloroethylene, and sodium chloride are presented. A companion paper presents the results of the flow and transport calculations needed for this approach to surfactant flooding. 相似文献