全文获取类型
收费全文 | 8712篇 |
免费 | 1465篇 |
国内免费 | 4758篇 |
专业分类
安全科学 | 1220篇 |
废物处理 | 355篇 |
环保管理 | 671篇 |
综合类 | 7251篇 |
基础理论 | 2619篇 |
环境理论 | 2篇 |
污染及防治 | 2064篇 |
评价与监测 | 459篇 |
社会与环境 | 186篇 |
灾害及防治 | 108篇 |
出版年
2024年 | 38篇 |
2023年 | 271篇 |
2022年 | 430篇 |
2021年 | 479篇 |
2020年 | 422篇 |
2019年 | 434篇 |
2018年 | 530篇 |
2017年 | 639篇 |
2016年 | 730篇 |
2015年 | 715篇 |
2014年 | 695篇 |
2013年 | 900篇 |
2012年 | 955篇 |
2011年 | 863篇 |
2010年 | 755篇 |
2009年 | 823篇 |
2008年 | 625篇 |
2007年 | 681篇 |
2006年 | 706篇 |
2005年 | 545篇 |
2004年 | 446篇 |
2003年 | 373篇 |
2002年 | 307篇 |
2001年 | 291篇 |
2000年 | 244篇 |
1999年 | 203篇 |
1998年 | 149篇 |
1997年 | 138篇 |
1996年 | 112篇 |
1995年 | 103篇 |
1994年 | 65篇 |
1993年 | 64篇 |
1992年 | 52篇 |
1991年 | 28篇 |
1990年 | 19篇 |
1989年 | 16篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 5篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 30篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Market samples (60) of six seasonal vegetables were monitoredduring 1996–1997 to determine the magnitude of pesticidalcontamination. The estimation of insecticide residuesrepresenting four major chemical groups i.e. organochlorine,organophosphorous, synthetic pyrethroid and carbamate, was doneby adopting a multiresidue analytical technique employingGC-ECD and GC-NPD systems with capillary columns. The testedsamples showed 100% contamination with low but measurableamounts of residues. Among the four chemical groups, theorganophosphates were dominant followed by organochlorines,synthetic pyrethroids and carbamates. About 23% of the samplesshowed contamination with organophosphorous compounds abovetheir respective MRL values. More extensive studies coveringdifferent regions of Haryana state are suggested to get a clearidea of the magnitude of vegetable contamination with pesticideresidues. 相似文献
42.
This paper discusses the REAP1 model and its application for the analysis of CO2 reduction and waste management policies for Japanese petrochemicals. The pros and cons of this modelling approach in comparison to other tools is elaborated. This is followed by a discussion of the model code and the modelling results. The results show that CO2 policies can have significant impacts on waste flows and waste policies can have significant CO2 benefits. As a consequence both effects must be considered in policy assessment. Pricing instruments are recommended instead of regulations because of the complex physical relations in the materials life cycle that extend beyond sector boundaries. A taxation approach is superior to a subsidy approach because rebound effects can be avoided. 相似文献
43.
Fagundez LA Fernández VL Marino TH Martín I Persano DA Rivarola Y Benítez M Sadañiowski IV Codnia J Zalts A 《Environmental monitoring and assessment》2001,71(1):61-70
Passive diffusion samplers were employed in San Miguel(Buenos Aires Metropolitan Area) for a preliminary airpollution monitoring. The highest loads were observedin downtown, compared with an urban background site.Total suspended particulate matter (TSPM) varied from0.257 to 0.033 mg cm-2 month-1; dust was examinedfor particle nature and size distribution. A similartrend was observed for nitrogen dioxide (NO2) andTSPM spatial distribution, suggesting that traffic isthe major pollution source. Sulphur dioxide (SO2)values were low and rather homogeneous. Levels for theinvestigated pollutants are below EPA's guide linevalues. Geographic (flat area, near to Rio de LaPlata) and climatologic factors (rainfalls andvariable wind directions) contribute to disperse pollutants. 相似文献
44.
通过实验与实际工程相结合,定量描述了大气采样系统中金属氧化物的存在对SO2测定值的影响,并阐述了其反应机理,提出了相应措施。 相似文献
45.
工作场所空气中硫酸雾(SO3)的分析 总被引:1,自引:0,他引:1
王连弟 《环境监测管理与技术》1997,9(3):36-37
采用碘量法测定工作场所空气中的三氧化硫及硫酸雾,三氧化硫及硫酸雾经中性水吸收后与碘化钾和碘酸钾反应,析出的碘与淀粉指示剂作用产生蓝色,进行比色测定。 相似文献
46.
Thin-film technique is becoming an industry standard for the preparation of TiO2-based photocatalyst for organic destruction. The catalyst provides several advantages over the conventional powder TiO2 in the treatment of wastewater and groundwater. In this study, a continuous stir flow reactor model is developed capable of describing the photocatalytic process. The model incorporates the following fundamental mechanisms: adsorption, diffusion, liquid-film transfer, UV attenuation, and photocatalytic reaction. All of the simulation results indicate that there exists a highly nonlinear relation between each of these parameters and the destruction rate. Various incident light intensities also are incorporated to simulate the energy efficiency. The simulations illustrate that the photocatalytic model can be used to elucidate the effect of process variables. It is also possible to “custom-design” a catalyst for the treatment of a particular waste stream. 相似文献
47.
根据塔里木油田1993-1996年环境空气监测数据,对其环境空气质量状况进行了分析和评价。 相似文献
48.
运用灰色系统理论,结合实例详细介绍了GM(1,1)模型在大气环境浓度预测中的应用。 相似文献
49.
对GAM水环境预测模型提出了四点不同看法,与有关作者商榷,指出GM(1,1)模型与GAM模型二者并无优劣之差,精度亦相当。 相似文献
50.
唐山市空气中SO2与TSP污染状况分析 总被引:1,自引:0,他引:1
分析了唐山市从1988年至1992年大气中SO2和TSP的污染状况和变化规律,取得对该市环境管理的科学依据。 相似文献