全文获取类型
收费全文 | 453篇 |
免费 | 2篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 16篇 |
废物处理 | 29篇 |
环保管理 | 62篇 |
综合类 | 41篇 |
基础理论 | 70篇 |
环境理论 | 2篇 |
污染及防治 | 155篇 |
评价与监测 | 69篇 |
社会与环境 | 16篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 8篇 |
2022年 | 34篇 |
2021年 | 17篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 10篇 |
2017年 | 13篇 |
2016年 | 11篇 |
2015年 | 9篇 |
2014年 | 25篇 |
2013年 | 58篇 |
2012年 | 26篇 |
2011年 | 19篇 |
2010年 | 18篇 |
2009年 | 15篇 |
2008年 | 20篇 |
2007年 | 22篇 |
2006年 | 19篇 |
2005年 | 23篇 |
2004年 | 14篇 |
2003年 | 8篇 |
2002年 | 9篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1994年 | 3篇 |
1992年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1984年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 2篇 |
1963年 | 1篇 |
1962年 | 2篇 |
1959年 | 2篇 |
1958年 | 1篇 |
1956年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有461条查询结果,搜索用时 15 毫秒
361.
The oil and gas industry forms a vital and large part of the economy of any country. It provides crucial support to transport, manufacturing and energy sectors, produces valuable exports and provides huge employment. This industry along with fertilizer plants, petrochemical plants, etc., which handle hazardous chemicals, are potential targets for deliberate actions by terrorists, criminals and disgruntled employees. The process industries face different levels of threats. It is imperative to analyze the entire threat scenario before taking steps to counter it, otherwise each and every threat will have to be treated as most severe, thus resulting in a huge and wasteful expenditure.The Security Risk Factor Table (SRFT) and a Stepped Matrix Procedure (SMP) have been developed to assess the security risk of oil and gas industry as well as the other chemical process industries. While the SRFT deals with the effects of individual threats, the SMP deals with the cascading/domino effects which a lone, low probability event can cause. A case study of a refinery has been performed to show the application of the ideas presented. 相似文献
362.
Effective wastewater treatment through conventional methods that rely on heavy aeration are expensive to install and operate. Duckweed is capable of recovering or extracting nutrients or pollutants and is an excellent candidate for bio-remediation of wastewaters. Such plants grow very fast, utilizing wastewater nutrients and also yield cost effective protein-rich biomass as a by-product. Duckweeds being tiny surface-floating plants are easy to harvest and have an appreciable amount of protein (15%–45% dry mass basis) and a lower fiber (7%–14% dry mass basis) content. Besides nutrient extraction, duckweeds has been found to reduce total suspended solids, biochemical oxygen demand (BOD), and chemical oxygen demand in wastewater significantly. Depending on the initial concentrations of nutrients, duckweed-covered systems can remove nitrate (NO3?) at daily rates of 120–590 mg NO3? m?2 (73%–97% of initial concentration) and phosphate (PO4?) at 14–74 mg PO4? m?2 (63%–99% of initial concentration). Removal efficiencies within 3 days of 96% and 99% have been reported for BOD and ammonia (NH3). Besides several genera of duckweeds (Spirodela, Lemna, Wolffia), other surface-floating aquatic plants like water hyacinth (Eichhornia) are well known for their phyto-remediation qualities. 相似文献
363.
ABSTRACTThis case study was conducted in Himalayan watershed to understand traditional farming and socio-economic status of the people in Kumaon Himalaya, Uttarakhand, India. In spite of high literacy rate in this area, their livelihood security is reliant on traditional farming practices that include agroforestry beside forest produce. More than 85% farming is rainfed and managed in a traditional way. Land holding size owned by farmers in the area extended from 0.57 to 2.57 ha but majority of farmers (51–80%) had farms of size less than 0.50 ha. The study revealed that forests provided 73–79% of required energy from fuelwood and more than 81% fodder. Agroforestry, livestock (dairy and poultry/goat rearing) and labour employment are the major sources of income to the people in the watershed. The income of people was positively correlated with livestock rearing and traditional farming. 相似文献
364.
1,3-Oxazines have a wide variety of biological activities. Naphthoquinone scaffolds also exhibit several biological responses such as antithrombotic, apoptosis and lipoxygenase inhibitors. There is, therefore, a need to develop efficient green methodologies for hybridizing the two scaffolds in a single entity. Herein, we report a novel protocol for the synthesis of 3-aryl-3,4-dihydro-2H-naphtho[2,3-e][1,3]oxazine-5,10-diones by one-pot three-component condensation of 2-hydroxy-1,4-naphthoquinone, aromatic amines and formaldehyde in glycerol at 50 °C. After separation of products, the glycerol–water layer was extracted using ethyl acetate and the dried glycerol layer was successfully reused several times. The products were obtained in 85–95 % yields in 5–10 min. This environmentally benign protocol holds advantages of high yields, operational simplicity and easy workup over our earlier report. 相似文献
365.
The synthesis of high-molecular-weight lactic acid based polymers by chain linked polymerization was investigated. Lactic acid based hydroxyl terminated telechelic prepolymer was synthesized and then the molecular weight was increased by chain linked polymerization using methylene diphenyldiisocyanate. All polymerizations were carried out in the melt, using tin octoate as catalyst. The products were characterized by Differential scanning calorimetry, nuclear magnetic resonance spectroscopy and size exclusion chromatography. With the increase in diisocyanate concentration, an increase in the glass transition temperature, molecular weight and molecular weight distribution was observed. 相似文献
366.
Optimization of regional hazardous waste management systems: an improved formulation 总被引:1,自引:0,他引:1
The planning and design of regional hazardous waste management system (RHWMS) involves selection of treatment and disposal facilities, allocation of hazardous wastes and waste residues from generator to the treatment and disposal sites and selection of the transportation routes. An improved formulation based upon multi-objective integer programming approach is presented to arrive at the optimal configuration of RHWMS components. This formulation addresses important practical issues like unique characteristics of the hazardous wastes reflecting on waste–waste and waste–technology compatibility. A utility function approach is presented to integrate both cost and risk related objectives. An illustrative case example is presented to demonstrate the usefulness of the improved formulation as a tool which can be used by environmental planning agencies in regional planning for hazardous waste management. 相似文献
367.
368.
Bherwani Hemant Anjum Saima Gupta Ankit Singh Anju Kumar Rakesh 《Environment, Development and Sustainability》2021,23(11):15857-15880
Environment, Development and Sustainability - Local climate in an area is significantly affected by the extent of urbanization. The microclimatic parameters such as wind speed (W), relative... 相似文献
369.
In the present study, the magnitude of contamination of vegetables with heavy metals (Pb, Zn, Cd, Cr, Cu and Zn) was determined in a long-term wastewater-irrigated agricultural land. Heavy metal concentrations in vegetables were several folds higher in wastewater-irrigated site compared to clean water-irrigated area. The wastewater-irrigated crops analysed in this study are heavily contaminated with heavy metals. Concentrations of Pb, Zn, Cd and Cr in all the sewage-fed vegetables were beyond the safe limit of FAO/WHO and Indian standard. Contamination is at its highest level in radish and spinach. Daily intake values of Pb, Cd and Ni through consumption of sewage-fed vegetables exceeded the recommended oral dose of metal for both adult and children. The study concludes that wastewater irrigation led to accumulation of heavy metals in vegetables causing potential health risk to consumers. 相似文献
370.
The ecotoxicities of three organic compounds containing spacer groups, an intermediate organotin premonomer, four organotin monomers, their homopolymers and six copolymers of tributylin α‐chloroacrylate (TCA) are reported against two microorganisms viz., Pseudomonas aeruginosa and Sarcina lutea and a larval species Anemia salina (Nauplii II). The organic compounds containing spacer group were less toxic whereas the monomers were found to be highly toxic. The homopolymers were found to be more toxic than that of tributyltin acrylate (TBTAA), tributyltin methacrylate (TBTMA) and tributyltin α‐Chloroacrylate (TCA). The toxicity of TCA copolymers increased with the increase in tributyltin (TBT) content in the polymer. From this study it was not possible to establish any relationship between the chemical nature of the comonomer with its toxicity. 相似文献