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901.
测量不确定度(uncertainty of measurement)是表征合理地赋予被测量之值的分散性,与测量结果相联系的参数。不确定度一词指可疑程度,广义而言,测量不确定度是对测量结果正确性的可疑程度。标准溶液作为一种标准物质,有许多优点,比如使用方便、溶液均匀、量值准确等。在环境监测分析中经常要使用标准溶液,在配制过程产生不确定度,而标准溶液的不确定度直接影响检测结果的不确定度,因此,对自配标准溶液的测量不确定度进行合理评定,显得尤为重要。配制标准溶液时的合成不确定度与称量的溶质质量、物质的纯度、配制体积、环境温度的不确定度等有关,充分分析不确定度的来源上,得出其扩展不确定度。并以亚硝酸盐标准溶液为例,全面分析了影响标准溶液不确定度的因素,给出了不确定度评定的具体过程和方法。 相似文献
902.
903.
904.
铁路边界噪声限值测量中若干问题的讨论 总被引:1,自引:0,他引:1
阐述了铁路边界噪声测量中所遇到的问题主要有,铁路边界的界定,背景噪声的修正和测点距轨面相对高度、测点与轨道的地面状况,并对铁路噪声预测模式进行了对比分析,以及如何测量等实际问题提出了解决办法。 相似文献
905.
906.
Tineke LambooyAuthor Vitae 《Journal of Cleaner Production》2011,19(8):852-866
Freshwater scarcity is no longer limited to sub-Saharan developing countries; also in Western society, access to unlimited amounts of freshwater is not assured at all times. It has been argued - and laid down in many national legal systems - that access to freshwater is a basic human right. What if corporate freshwater use threatens to interfere with this human right? The main focus of the article is to explore the role of today’s companies in relation to freshwater. A number of tools have been developed to attend to the necessity to reduce corporate use of freshwater. The article discusses specialised water reporting instruments such as the 2007 Global Water Tool and the ‘water footprint’ calculation method. In addition, attention is paid to a CERES report (2010) revealing that the majority of the 100 world’s leading companies in water-intensive industries still has weak management and disclosures of water-related risks and opportunities. To obtain concrete information about corporate water strategies and practices, an explorative analysis was conducted on 20 Dutch multinational companies. The article highlights various innovative practices. In sum, it is demonstrated that companies are expected to bear responsibility for their impact on water resources, in particular when it influences public access to water in areas with freshwater scarcity and/or weak government. Notwithstanding the critical conclusions of the CERES report, it is interesting to see an evolution in corporate research concerning sustainable water use and the development of greener products and greener ways of production. 相似文献
907.
According to the logic process of carbon reduction in China which arises from the measurement to reduction, from reduction to offsetting, the measurement of carbon emission in the tourism industry was the first and key step. Based on the life cycle assessment theory and input–output analysis, this article used economic and environmental measurement technologies, The System of National Accounting (SNA), Tourism Satellite Account (TSA), System of Integrated Environment and Economic Accounting (SEEA), and so on, and built up a top-down carbon emission analysis framework for the tourism industry and estimated carbon emission of the tourism industry in China in 2007. The finding showed that the total carbon emission of the tourism industry in China in 2007 was 169.78 million tons, covering 2.71% of carbon emission of all industries in China in 2007, and 2.44% of the total carbon emission in China in 2007. The direct carbon emission of the tourism industry in China in 2007 was 73.56 million tons, including transportation (50.14 million tons), sightseeing (1.33 million tons), lodging (4.19 million tons), accommodation (4.73 million tons), shopping (8.14 million tons), entertainment (0.67 million tons), communication (0.45 million tons), and others (3.90 million tons). The indirect carbon emission of the tourism industry in China in 2007 was 96.23 million tons, mostly contributed by coking, gas, and petroleum processing industries, transportation and warehousing industry, machinery and equipment manufacturing industry, and food manufacturing and tobacco processing industry, which covered 57%. 相似文献
908.
在北京上甸子区域大气本底站利用气相色谱/质谱联用(GC-MS)系统对大气中11种氢氟碳化物(HFCs)开展在线观测研究.2018年1~12月,HFC-23、HFC-32、HFC-125、HFC-134a、HFC-143a、HFC-152a、HFC-227ea、HFC-236fa、HFC-245fa、HFC-365mfc、HFC-4310mee本底数据浓度分别为:(31.9±0.4)×10-12、(22.1±1.7)×10-12、(29.3±1.3)×10-12、(110.2±2.4)×10-12、(24.0±0.3)×10-12、(10.3±0.7)×10-12、(1.59±0.04)×10-12、(0.19±0.01)×10-12、(3.30±0.08)×10-12、(1.27±0.03)×10-12、(0.28±0.01)×10-12;本底数据出现频率分别为:34.5%、23.4%、22.5%、24.6%、24.5%、42.5%、24.3%、46.4%、38.3%、68.1%、77.9%;非本底数据浓度分别为:(39.2±11.1)×10-12、(47.7±21.8)×10-12、(38.6±8.7)×10-12、(137.3±15.7)×10-12、(26.1±2.2)×10-12、(15.9±7.0)×10-12、(2.77±1.11)×10-12、(0.25±0.06)×10-12、(4.10±0.97)×10-12、(1.34±0.06)×10-12、(0.30±0.01)×10-12.HFC-32、HFC-125、HFC-134a、HFC-143a、HFC-227ea本底浓度呈线性上升趋势,年增长率分别为:4.4×10-12,3.8×10-12,7.3×10-12,1.0×10-12,0.14×10-12a-1,而HFC-152a呈现明显的季节变化.以CO为示踪物利用示踪物比值相关法估算了HFC-23、HFC-32、HFC-125、HFC-143a、HFC-152a、HFC-236fa、HFC-245fa排放量,分别为6.4,17,14,27,4.0,0.10,1.3kt/a. 相似文献
909.
Xianbao Shen Zhiliang Yao Qiang Zhang David Vance Wagner Hong Huo Yingzhi Zhang Bo Zheng Kebin He 《环境科学学报(英文版)》2015,27(5):209-220
A database of real-world diesel vehicle emission factors, based on type and technology, has been developed following tests on more than 300 diesel vehicles in China using a portable emission measurement system. The database provides better understanding of diesel vehicle emissions under actual driving conditions. We found that although new regulations have reduced real-world emission levels of diesel trucks and buses significantly for most pollutants in China,NOx emissions have been inadequately controlled by the current standards, especially for diesel buses, because of bad driving conditions in the real world. We also compared the emission factors in the database with those calculated by emission factor models and used in inventory studies. The emission factors derived from COPERT (Computer Programmer to calculate Emissions from Road Transport) and MOBILE may both underestimate real emission factors, whereas the updated COPERT and PART5 (Highway Vehicle Particulate Emission Modeling Software) models may overestimate emission factors in China. Real-world measurement results and emission factors used in recent emission inventory studies are inconsistent, which has led to inaccurate estimates of emissions from diesel trucks and buses over recent years. This suggests that emission factors derived from European or US-basedmodels will not truly represent real-world emissions in China. Therefore, it is useful and necessary to conduct systematic real-world measurements of vehicle emissions in China in order to obtain the optimum inputs for emission inventory models. 相似文献
910.
Rodrigo Goyannes Gusmão Caiado Osvaldo Luiz Gonçalves Quelhas Daniel Luiz Mattos Nascimento Rosley Anholon Walter Leal Filho 《国际发展与全球生态学杂志》2018,25(4):312-326
In recent years, sustainability issues are gaining greater prominence among organizations and their stakeholders around the world. This paper aims to verify the sustainability performance of Brazilian organizations in performance measures and to propose sustainable guidelines with the intention of directing future efforts to the transition to sustainable development. The research utilized a triangulated approach by collecting qualitative and quantitative data acquired through multiple collection methods of a theoretical literature review, documentary analysis of corporate reports, questionnaire survey and semi-structured interviews with industry professionals and academic researchers. The results show that internal organizational factors are the main inductors of the sustainable environment in organizations, and sustainability must be tied to strategic planning, starting from upper management to lower levels. It is essential to use sustainable performance measurement systems in order to respond to external and internal levers and serve as benchmarking for future corporate operations and strategies. In addition, it is the responsibility of organizations to focus their efforts on environmental protection, reduction of energy, corporate reputation, quality management, customer satisfaction and investor relations, as they are considered to be more important and have a relationship of dependence on organizational sustainability. The findings will be of value to professionals and academics who want to start measuring and for continuously improving the sustainability performance of their organizations according to the technical, economic, environmental, social and governance dimensions. This research work also helps to understand the perceptions and expectations of stakeholders. 相似文献