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831.
Abdul-Wahab SA 《Environmental management》2004,34(3):372-382
The CAL3QHC model was used to predict carbon monoxide (CO) concentrations from motor vehicles at an existing urban intersection (Star Cinema in Muscat area, Oman). The CO concentrations predicted from the model were compared with those measured in the field. Predicted average CO concentrations were found to compare favorably with measured values obtained at all eight receptors considered within the modeled intersection. In general, the comparison indicates good agreement with some underprediction for CO. For receptor 6, the model overpredicts the average CO concentration. This overprediction is associated with the presence of trees and green area in the location of receptor 6. In general, the measurements and the model results indicated that the highest CO concentrations were found to occur close to the intersection and, hence, a decrease in the concentration levels was seen as the distance from the road increased. The results indicated that the levels of CO were well below the ambient air quality standard and that probably no health risk was present in areas adjacent to the star cinema intersection. However, the predicted worst-case 1-h CO concentrations assuming inversion atmospheric stability conditions (class F) and wind speed of 1 m/s indicated that the levels of CO were close to or higher than the Omans National Ambient Air Quality Standards (NAAQS) value of 35 ppm at all receptors considered. The results of this study are useful in transport development and traffic management planning.Published online. 相似文献
832.
PROBLEM: Many states have enacted graduated driver licensing (GDL) systems in an effort to reduce the very high crash rates of young beginning drivers. This article addresses how to achieve the maximum benefit from GDL by ensuring compliance with protective restrictions. ENHANCING GDL THROUGH SYSTEM STRUCTURE: The major crash reductions due to GDL systems result from the protective restrictions during the initial two levels, which isolate novice drivers from the highest risk driving situations. Accordingly, GDL systems should include protective restrictions that adequately control the greatest dangers facing young drivers: multiple teen passengers and night driving before midnight. ENCOURAGING COMPLIANCE THROUGH SYSTEM STRUCTURE: Including protective restrictions that are supported by parents and teens will encourage compliance. Furthermore, linking a teen's advancement through GDL to demonstrated responsible driving will likely encourage compliance more than threatening punishment for violations. ENCOURAGING COMPLIANCE THROUGH ENFORCEMENT: Parents are in a prime position to enforce most GDL restrictions, but there is some evidence they do not enforce those restrictions that they consider too extreme. Little is currently known about the involvement of law enforcement in GDL systems, but there is potential for high visibility law enforcement activities to encourage compliance with restrictions. IMPACT ON RESEARCH, PRACTICE, AND POLICY: There is a need for better designed GDL systems in many states; more research is needed to examine compliance with restrictions and to evaluate enforcement efforts by parents and law enforcement. 相似文献
833.
Individual bees often restrict their visits to only a few species out of the multitude of available plants. This flower constancy
is likely caused by limitations of memory for motor patterns, sensory stimuli, or reward levels. Here we test the implications
of sensori-motor learning and memory for flower constancy. Artificial “flowers” with two distinct “morphologies” were used,
so that in each flower type, a different motor pattern was needed to reach the nectar. As in natural flowers, these morphological
types were associated with sensory signals (blue and yellow color stimuli). Bees which learned only a single task were more
efficient in several ways than those which had learned two: they made fewer errors, had shorter flower handling times, took
shorter times to correct errors, and transitions between flowers were initially more rapid. For bees which had learned two
tasks, performance depended strongly on the training schedule: if each task was learned with blocked trials, the memory for
the second appeared to interfere with that for the first. Interference affected only the association between flower signal
and motor pattern, not the motor pattern itself. This was not the case if bees were trained for both tasks with alternating
trials. In that case, bees rapidly learned both tasks, albeit with worse saturation levels than bees which had learned only
one. Bees transferred the experience gained on one task to a second task: their initial performance on the second task was
better than their initial performance on the first. On the other hand, performance on the second task in the saturation level (in which bees no longer improve their efficiency) was worse than on the first task (negative transfer). In the saturation
phase, performance did not directly depend on switch frequency, but on whether the bee had one or two options in memory. Thus,
while bees would become proficient at two tasks more quickly if their acquisition phase included switches, such switches had
no measurable effect in the saturation phase. The implications of these findings for foraging are discussed using modern learning
theory.
Received: 4 April 1997 / Accepted after revision: 8 August 1997 相似文献
834.
Shin-ichi Sakai Yukio Noma Akiko Kida 《Journal of Material Cycles and Waste Management》2007,9(2):151-158
The Japanese Government introduced the Law on Recycling of End-of-Life Vehicles (ELV Recycling Law) in 2002. This law requires
manufacturers to retrieve chlorofluorocarbons (CFCs), airbags, and automobile shredder residue (ASR) from ELVs and to properly
recycle the remaining materials. This framework is compared with European ELV directives. Pilot-scale incineration plant testing
has revealed a greater formation of by-product persistent organic pollutants (POPs) during the primary combustion of ASR compared
to normal municipal solid waste. This may be attributed to the abundance of chlorine, Cu, and Fe in ASR, as Cu and Fe have
been found to catalyze the formation of POPs under certain conditions. However, most by-product POPs were destroyed by the
secondary combustion, and almost all were removed after flue gas treatment. The direct melting system is a shaft-type gasification
and melting technology that has proved effective in many municipal solid waste applications. This system can be applied to
ASR recycling for effective decomposition of brominated flame retardants and polybrominated dioxins. 相似文献
835.
目的科学设置装甲车辆驾驶考核限制路尺寸。方法采用Visio绘图工具,对装甲车辆车体、运动状态、道路进行模拟仿真,根据装甲车辆行驶性能参数,测算不同限制路尺寸的理论值。结果通过仿真测算,某新型装甲车辆通过的五杆弯道限制路理论最小总长为42 m,理论最小入口宽为4 m,实际尺寸初始值设置为总长50 m,入口宽为4.5 m。结论采用Visio绘图仿真的方法能够科学准确地进行装甲车辆限制路尺寸设置,为新型装甲车辆限制路尺寸设置提供有效的数据支撑。 相似文献
836.
浙江省机动车主要污染物减排是"十二五"大气主要污染物减排的重要组成部分,为完成国家下达的机动车主要污染物减排目标,根据浙江省机动车保有量及污染物排放量现状,预测"十二五"期间机动车增长带来的污染物排放情况,着重分析影响浙江省机动车氮氧化物排放量的关键因素,并从淘汰"黄标车"、提高油品质量和加强管理等方面提出相应减排对策,分析浙江省机动车主要污染物的减排可达性。 相似文献
837.
全国机动车保有量——《2013年中国机动车污染防治年报》(第1部分) 总被引:1,自引:0,他引:1
环境保护部日前发布《2013年中国机动车污染防治年报》,公布了2012年全国机动车污染排放状况..本期“研究成果展示”专栏以六篇形式连载。本文刊载2012年全国机动车保有量及其变化趋势的内容,以飨读者。该年报指出,(1)2012年,全国机动车保有量2.24亿辆。其中汽车10837.8万辆,低速汽车1145.0万辆,摩托车10400.0万辆。,与往年不同,汽车保有量已超过摩托车保有量,占主导地位..(2)2012年,全国汽车保有量10837.8万辆。其中,按车型分类,客车占82.5%,货车占17.5%;按燃料类型分类,汽油车占82.5%,柴油车占16.1%,燃气车占1.4%;按排放标准分类,国I前标准的汽车占7.8%,国I标准的汽车占14.9%,国Ⅱ标准的汽车占15.7%,国Ⅲ标准的汽车占51.5%,国Ⅳ及以上标准的汽车占10.1%;按环保标志分类,“黄标车”占13.4%,“绿标车”占86.6%..(3)2010—2012年全国机动车保有量呈快速增长态势,由19(106.2万辆增加到22382.8万辆,年均增长8.5%。其中,汽车保有量由7721,7万辆增加到10837.8万辆,年均增长18.5%;“黄标车”保有量由1558.3万辆降低到1451.4万辆,年均削减3.5%. 相似文献
838.
环境保护部目前发布《2013年中国机动车污染防治年报》,公布了2012年全国机动车污染排放状况。本期“研究成果展示”专栏以六篇形式连载。本文刊载关于全国机动车氮氧化物总量减排的内容,以飨读者。 相似文献
839.
840.
Lijun Hao Wei Chen Lei Li Jianwei Tan Xin Wang Hang Yin Yan Ding Yunshan Ge 《环境科学学报(英文版)》2017,29(5):109-117
An instantaneous emission model was developed to model and predict the real driving emissions of the low-speed vehicles. The emission database used in the model was measured by using portable emission measurement system (PEMS) under actual traffic conditions in the rural area, and the characteristics of the emission data were determined in relation to the driving kinematics (speed and acceleration) of the low-speed vehicle. The input of the emission model is driving cycle, and the model requires instantaneous vehicle speed and acceleration levels as input variables and uses them to interpolate the pollutant emission rate maps to calculate the transient pollutant emission rates, which will be accumulated to calculate the total emissions released during the whole driving cycle. And the vehicle fuel consumption was determined through the carbon balance method. The model predicted the emissions and fuel consumption of an in-use low-speed vehicle type model, which agreed well with the measured data. 相似文献