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451.
张伦文 《中国特种设备安全》2013,(10):26-28
本文通过电梯补偿链过长过短影响电梯正常检验和使用的实例,阐述电梯补偿链固定点在电梯运行使用过程中存在空间位置的变化的原因,强调电梯补偿链长度在检验中应注意的事项。 相似文献
452.
Defining Indicators and Standards for Tourism Impacts in Protected Areas: Cape Range National Park,Australia 总被引:2,自引:0,他引:2
Visitors’ perceptions of impacts and acceptable standards for environmental conditions can provide essential information for
the sustainable management of tourist destinations, especially protected areas. To this end, visitor surveys were administered
during the peak visitor season in Cape Range National Park, on the northwest coast of Western Australia and adjacent to the
iconic Ningaloo Reef. The central focus was visitors’ perceptions regarding environmental conditions and standards for potential
indicators. Conditions considered of greatest importance in determining visitors’ quality of experience included litter, inadequate
disposal of human waste, presence of wildlife, levels of noise, and access to beach and ocean. Standards were determined,
based on visitors’ perceptions, for a range of site-specific and non-site-specific indicators, with standards for facilities
(e.g., acceptable number of parking bays, signs) and for negative environmental impacts (e.g., levels of littering, erosion)
sought. The proposed standards varied significantly between sites for the facilities indicators; however, there was no significant
difference between sites for environmental impacts. For the facilities, the standards proposed by visitors were closely related
to the existing situation, suggesting that they were satisfied with the status quo. These results are considered in the context
of current research interest in the efficacy of visitor-derived standards as a basis for protected area management. 相似文献
453.
454.
建设开发区是我国探索社会主义市场经济建设的一项重大举措,对吸引外资和发展经济起到了十分重要的作用,但开发区建设中的环境保护管理工作却是我国建设项目环境管理中的薄弱环节。本文通过对开发区建设环境保护管理工作中存在的问题及产生原因的分析,提出了加强开发区建设环境保护管理工作的一些思路,以减少人为干扰,增加环境保护工作的指导性。 相似文献
455.
456.
457.
介绍了催化柴油加氢精制装置汽提塔顶冷却系统设备腐蚀的原因,并结合装置的实际情况提出了防腐措施。 相似文献
458.
城市环保在城市建设和居民日常生活中都具有很重要的地位.本文对城市环保工作及其执行部门运行机制设计的原则进行了探索,供环保系统和其它有关部门参考. 相似文献
459.
农业环保的经济损益分析 总被引:1,自引:0,他引:1
论述字农业环保经济损益分析的指标体系,提出了指标量化方法及经济损益分析方法,探讨了损益分析参数的实际意义。最后结合实例进行应用研究。 相似文献
460.
Volatile organic compounds (VOCs) are regulated aerial pollutants that have environmental and health concerns. Swine operations produce and emit a complex mixture of VOCs with a wide range of molecular weights and a variety of physicochemical properties. Significant progress has been made in this area since the first experiment on VOCs at a swine facility in the early 1960s. A total of 47 research institutions in 15 North American, European, and Asian countries contributed to an increasing number of scientific publications. Nearly half of the research papers were published by U.S. institutions.Investigated major VOC sources included air inside swine barns, in headspaces of manure storages and composts, in open atmosphere above swine wastewater, and surrounding swine farms. They also included liquid swine manure and wastewater, and dusts inside and outside swine barns. Most of the sample analyses have been focusing on identification of VOC compounds and their relationship with odors. More than 500 VOCs have been identified. About 60% and 10% of the studies contributed to the quantification of VOC concentrations and emissions, respectively. The largest numbers of VOC compounds with reported concentrations in a single experimental study were 82 in air, 36 in manure, and 34 in dust samples.The relatively abundant VOC compounds that were quantified in at least two independent studies included acetic acid, butanoic acid (butyric acid), dimethyl disulfide, dimethyl sulfide, iso-valeric, p-cresol, propionic acid, skatole, trimethyl amine, and valeric acid in air. They included acetic acid, p-cresol, iso-butyric acid, butyric acid, indole, phenol, propionic acid, iso-valeric acid, and skatole in manure. In dust samples, they were acetic acid, propionic acid, butyric acid, valeric acid, p-cresol, hexanal, and decanal. Swine facility VOCs were preferentially bound to smaller-size dusts.Identification and quantification of VOCs were restricted by using instruments based on gas Chromatography (GC) and liquid chromatography (LC) with different detectors most of which require time-consuming procedures to obtain results. Various methodologies and technologies in sampling, sample preparation, and sample analysis have been used. Only four publications reported using GC based analyzers and PTR-MS (proton-transfer-reaction mass spectrometry) that allowed continuous VOC measurement. Because of this, the majority of experimental studies were only performed on limited numbers of air, manure, or dust samples. Many aerial VOCs had concentrations that were too low to be identified by the GC peaks.Although VOCs emitted from swine facilities have environmental concerns, only a few studies investigated VOC emission rates, which ranged from 3.0 to 176.5 mg d−1 kg−1 pig at swine finishing barns and from 2.3 to 45.2 g d−1 m−2 at manure storages. Similar to the other pollutants, spatial and temporal variations of aerial VOC concentrations and emissions existed and were significantly affected by manure management systems, barn structural designs, and ventilation rates.Scientific research in this area has been mainly driven by odor nuisance, instead of environment or health concerns. Compared with other aerial pollutants in animal agriculture, the current scientific knowledge about VOCs at swine facilities is still very limited and far from sufficient to develop reliable emission factors. 相似文献