全文获取类型
收费全文 | 11133篇 |
免费 | 1088篇 |
国内免费 | 2795篇 |
专业分类
安全科学 | 2072篇 |
废物处理 | 228篇 |
环保管理 | 1932篇 |
综合类 | 7097篇 |
基础理论 | 940篇 |
环境理论 | 3篇 |
污染及防治 | 895篇 |
评价与监测 | 729篇 |
社会与环境 | 480篇 |
灾害及防治 | 640篇 |
出版年
2024年 | 70篇 |
2023年 | 312篇 |
2022年 | 467篇 |
2021年 | 537篇 |
2020年 | 625篇 |
2019年 | 466篇 |
2018年 | 371篇 |
2017年 | 511篇 |
2016年 | 496篇 |
2015年 | 641篇 |
2014年 | 610篇 |
2013年 | 729篇 |
2012年 | 862篇 |
2011年 | 955篇 |
2010年 | 675篇 |
2009年 | 667篇 |
2008年 | 494篇 |
2007年 | 728篇 |
2006年 | 708篇 |
2005年 | 567篇 |
2004年 | 485篇 |
2003年 | 440篇 |
2002年 | 401篇 |
2001年 | 323篇 |
2000年 | 277篇 |
1999年 | 255篇 |
1998年 | 220篇 |
1997年 | 175篇 |
1996年 | 159篇 |
1995年 | 157篇 |
1994年 | 118篇 |
1993年 | 100篇 |
1992年 | 80篇 |
1991年 | 46篇 |
1990年 | 30篇 |
1989年 | 20篇 |
1988年 | 15篇 |
1987年 | 24篇 |
1986年 | 24篇 |
1985年 | 17篇 |
1984年 | 14篇 |
1983年 | 10篇 |
1982年 | 17篇 |
1981年 | 13篇 |
1980年 | 21篇 |
1979年 | 12篇 |
1978年 | 17篇 |
1977年 | 9篇 |
1972年 | 8篇 |
1971年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
511.
Youfen Xu Zong Li Ruyin Liu Hongxia Liang Zhisheng Yu Hongxun Zhang 《Frontiers of Environmental Science & Engineering》2020,14(4):67
512.
Yilei Lu Yunqing Huang Siyu Zeng Can Wang 《Frontiers of Environmental Science & Engineering》2020,14(2):21
513.
Sargaonkar A 《Environmental monitoring and assessment》2006,117(1-3):491-503
Non-point source (NPS) pollution is the result of various land use practices such as agriculture, sites of construction and
waste disposal, urban development and so on. The control of NPS pollution is possible by regular monitoring and assessment
on watershed basis to educate people for implementing well-known structural and non-structural measures. Recent trend is to
use GIS based modelling tool for assessment of rainfall-runoff and non-point loading. The approach requires generation and
analysis of basin wide data on various features of land and estimates of Event Mean Concentrations (EMCs) of pollutants in
the runoff. In the present paper, basin wide data in different districts of Tapi basin has been analysed for land use distribution;
fertilizer application; low, medium and high-density habitation; and annual rainfall. Coefficients of runoff have been estimated
considering pervious and impervious area for different land use types, and compared with the reported values for Indian conditions.
The estimated mean annual runoff flow indicated that two districts Jalgaon and Dhule contribute maximum runoff to the Tapi
River. Estimates of EMCs for BOD and nutrients (N and P) in the runoff from various districts are useful in GIS-based modelling
study for NPS pollution assessment. 相似文献
514.
The Atlantic Coastal Action Program (ACAP) is a unique, community-based program initiated by Environment Canada in 1991 to help Atlantic Canadians restore and sustain watersheds and adjacent coastal areas. ACAP is the eastem-most Environment Canada Ecosystem Initiative. The ACAP family is currently made up of 14 ecosystem-based organizations in the four Atlantic provinces. Each one of these non-profit organizations operates independently, but is formally linked under the umbrella of ACAP to represent a force stronger than the individual parts. In Environment Canada's experience, the program consistently demonstrates the value of a community-based approach and produces results on an ecosystem basis. This paper will examine some of the impacts of ACAP in terms of economics, credible community science, and environmental results which most often align with Environment Canada's objectives. It will explore the influences of the community-based approach to environmental management on multiple scales (local, regional, etc.). Through examples, the paper will demonstrate the effectiveness of ACAP in influencing some of the policies, programs and attitudes of various levels of government and industry in the region, as well as describe how the community-based model has been exported internationally. The paper will conclude with a discussion on a planned path forward for ACAP. 相似文献
515.
516.
Fakhradin Ghasemi Omid Kalatpour Abbas Moghimbeigi 《International journal of occupational safety and ergonomics》2018,24(2):303-310
Background. Unsafe behavior is closely related to occupational accidents. Work pressure is one the main factors affecting employees’ behavior. The aim of the present study was to provide a path analysis model for explaining how work pressure affects safety behavior. Methods. Using a self-administered questionnaire, six variables supposed to affect safety employees’ behavior were measured. The path analysis model was constructed based on several hypotheses. The goodness of fit of the model was assessed using both absolute and comparative fit indices. Results. Work pressure was determined not to influence safety behavior directly. However, it negatively influenced other variables. Group attitude and personal attitude toward safety were the main factors mediating the effect of work pressure on safety behavior. Among the variables investigated in the present study, group attitude, personal attitude and work pressure had the strongest effects on safety behavior. Conclusion. Managers should consider that in order to improve employees’ safety behavior, work pressure should be reduced to a reasonable level, and concurrently a supportive environment, which ensures a positive group attitude toward safety, should be provided. Replication of the study is recommended. 相似文献
517.
Agnieszka Ćwirlej-Sozańska Anna Wilmowska-Pietruszyńska Bernard Sozański 《International journal of occupational safety and ergonomics》2018,24(3):386-394
Purpose. To assess the reliability and validity of the Polish version of the 36-point World Health Organization Disability Assessment Schedule (WHODAS 2.0) in an elderly population. Method. One thousand randomly selected individuals, aged 60–70 years, living in south-eastern Poland were assessed using the Polish version of the WHODAS 2.0. Results. The analysis confirmed the high reliability and validity of the tool. Cronbach’s α index was 0.89. The tool had high stability, and the correlation between test and retest results was high. The relevance of the domain selection was high or very high. A factor analysis confirmed the relevance of assigning questions to domains. High theoretical relevance was also demonstrated. Statistically significant differences between those who were and were not suffering from health problems were observed. An analysis of the internal structure of the WHODAS 2.0 revealed strong correlations between the components of each domain and the final result. Conclusion. The Polish version of the WHODAS 2.0 showed high reliability and validity; thus, it can be used to assess health, functioning and disability in the elderly population of Poland. 相似文献
518.
为了探究火源功率和水幕线性喷水强度对烟气特征参数和水幕阻烟隔热能力的影响,以全尺寸隧道为研究对象,采用FDS数值模拟方法,还原验证了前人使用的小尺寸模型,研究了20组工况下烟气特征参数变化的规律。研究结果表明:根据相似性原理还原后的全尺寸模型在相同工况下的模拟结果与小尺寸实验基本一致;水幕系统降低遮光率的效果随线性喷水强度增加而增强,当线性喷水强度增至一定程度时,遮光率和隔热效率无明显变化;对于中、大型规模火灾,水幕有效作用时间出现减少的情况;火源功率为5,20,30 MW的小、中、大规模的隧道火灾,综合考虑经济性和水幕效果,建议分别选择水幕的线性喷水强度为8,14,16 L/(s瘙簚m)。 相似文献
519.
Long-lasting expansion of haze pollution in China has already presented a stern challenge to regional joint prevention and control. There is an urgent need to enlarge and reconstruct the coverage of joint prevention and control of air pollution in key area. Air quality models can identify and quantify the regional contribution of haze pollution and its key components with the help of numerical simulation, but it is difficult to be applied to larger spatial scale due to the complexity of model parameters. The time series analysis can recognize the existence of spatial interaction of haze pollution between cities, but it has not yet been used to further identify the spatial sources of haze pollution in large scale. Using econometric framework of time series analysis, this paper developed a new approach to perform spatial source apportionment. We applied this approach to calculate the contribution from spatial sources of haze pollution in China, using the monitoring data of particulate matter (PM2.5) across 161 Chinese cities. This approach overcame the limitation of numerical simulation that the model complexity increases at excess with the expansion of sample range, and could effectively deal with severe large-scale haze episodes. 相似文献
520.
Md Ayaz Chowdhury Saad Bin A. Kashem 《International Journal of Sustainable Engineering》2018,11(3):196-204
This paper presents a H∞ loop-shaping controller for controlling dc-link voltage by regulating the switching signal of the inverter associated with a grid-connected single-phase photovoltaic system. To facilitate a robust control design, state-space realisation of the system model is made with uncertainties represented by linear fractional transformation. The controller is achieved through H∞ synthesis followed by obtaining desired loop shapes through the choice of the proper weighting functions. The controller order is reduced by Henkel-norm method for facilitating its practical implementation. Controller performance is evaluated through carrying out simulations on MATLAB/Simulink platform under standard and changing atmospheric conditions, and fault condition. 相似文献