全文获取类型
收费全文 | 511篇 |
免费 | 9篇 |
国内免费 | 57篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 22篇 |
环保管理 | 51篇 |
综合类 | 123篇 |
基础理论 | 112篇 |
污染及防治 | 172篇 |
评价与监测 | 69篇 |
社会与环境 | 18篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 4篇 |
2022年 | 10篇 |
2021年 | 13篇 |
2020年 | 14篇 |
2019年 | 9篇 |
2018年 | 9篇 |
2017年 | 19篇 |
2016年 | 23篇 |
2015年 | 14篇 |
2014年 | 23篇 |
2013年 | 62篇 |
2012年 | 11篇 |
2011年 | 20篇 |
2010年 | 25篇 |
2009年 | 23篇 |
2008年 | 23篇 |
2007年 | 25篇 |
2006年 | 23篇 |
2005年 | 23篇 |
2004年 | 18篇 |
2003年 | 13篇 |
2002年 | 19篇 |
2001年 | 21篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 9篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1982年 | 5篇 |
1979年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1971年 | 4篇 |
1966年 | 4篇 |
1965年 | 5篇 |
1964年 | 4篇 |
1963年 | 5篇 |
1961年 | 6篇 |
1960年 | 2篇 |
1958年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有577条查询结果,搜索用时 31 毫秒
491.
492.
N Reid P K Misra R Bloxam D Yap S T Rao K Civerolo E Brankov R J Vet 《Journal of the Air & Waste Management Association (1995)》2001,51(11):1561-1567
Anomalies appear to exist in our understanding of atmospheric sulfur compounds, specifically as evidenced in the time trends of the different chemical forms of these compounds. Trends determined at a number of locations by several different groups seem to indicate that, responding to emission reductions across North America, the concentration of SO2 in the atmosphere is declining more rapidly than that of aerosol SO4(2-). A number of possible reasons for this discrepancy are examined, but it is not possible to provide a definitive answer at this stage. The intent is to stimulate debate, because shortcomings in our understanding of the processes involved could have profound implications for the credibility of abatement strategies and policies for both acid deposition and fine particulate matter (PM). 相似文献
493.
Robert E. Eskridge William B. Petersen S. Trivikrama Rao 《Journal of the Air & Waste Management Association (1995)》2013,63(3):312-317
Recent theoretical and experimental investigations Indicate that turbulent diffusion behind moving vehicles Is Influenced by the speed of the vehicle. Vertical wake induced turbulent diffusion, explicitly treated in the numerical ROADWAY model, is proportional to the square of the wind speed relative to the moving vehicle. Hence, the model predictions of turbulent mixing and pollutant concentrations on and downwind of a roadway are dependent upon the traffic speed. It Is expected from theoretical considerations that the effect of vehicle speed on pollutant concentrations will be more significant during stable atmospheric conditions, because in neutral and unstable conditions the vehicle-wake turbulence is quickly masked by the ambient turbulence. In this study, experimental data are utilized to evaluate the theoretical predictions of the effects of traffic speed on the ambient pollutant concentrations. The effects of vehicle speed upon ambient concentrations are investigated through wind tunnel experiments and field studies that used dual tracers. Consistent with predictions of the ROADWAY model, data obtained near the Long Island Expressway indicate that the influence of traffic speed on the ambient pollutant concentrations Is not significant during unstable and neutral conditions. The Long Island experiment did not provide sufficient field data to assess the model predictions of the traffic speed effect during stable atmospheric conditions. 相似文献
494.
Rucha Vaidya Kisan Kodam Vikram Ghole K. Surya Mohan Rao 《Journal of environmental management》2010,91(9):1821-1830
The aim of the present study was to devise and validate an appropriate treatment process for disposal of hazardous barium and cyanide waste into a landfill at a Common Hazardous Waste Treatment Storage Disposal Facility (CHWTSDF). The waste was generated during the process of hardening of steel components and contains cyanide (reactive) and barium (toxic) as major contaminants. In the present study chemical fixation of the contaminants was carried out. The cyanide was treated by alkali chlorination with calcium hypochlorite and barium by precipitation with sodium sulfate as barium sulfate. The pretreated mixture was then solidified and stabilized by binding with a combination of slag cement, ordinary Portland cement and fly ash, molded into blocks (5 × 5 × 5 cm) and cured for a period of 3, 7 and 28 days. The final experiments were conducted with 18 recipe mixtures of waste + additive:binder (W:B) ratios. The W:B ratios were taken as 80:20, 70:30 and 50:50. The optimum proportions of additives and binders were finalized on the basis of the criteria of unconfined compressive strength and leachability. The leachability studies were conducted using the Toxicity Characteristic Leaching Procedure. The blocks were analyzed for various physical and leachable chemical parameters at the end of each curing period. Based on the results of the analysis, two recipe mixtures, with compositions – 50% of [waste + (120 g Ca(OCl)2 + 290 g Na2SO4) kg?1 of waste] + 50% of binders, were validated for in situ stabilization into a secured landfill of CHWTSDF. 相似文献
495.
C. K. Sreedharan Jagannadha Rao Matta 《Environment, Development and Sustainability》2010,12(6):877-888
In a major deviation from conventional joint forest management approaches where the emphasis of management is on provision
of forest products to the participating villagers, the Tamil Nadu Afforestation Project (TAP) focused on poverty alleviation
as the principal means to achieve sustainable forest management. This study assesses the effectiveness of TAP’s strategy in
improving the ecology and socio-economic conditions of forest fringe villages using a diverse set of research methods. Results
indicate that in a span of four to seven years, there was significant increase in forest cover, biodiversity, and agricultural
productivity. The project villages have also shown considerable progress in various indicators of socio-economic development.
The authors, however, suggest continued poverty alleviation and promotion of alternative livelihood opportunities to place
the programme on a stable ground. Meeting the development needs of local villagers through strong and durable institutional
linkages is also suggested for the programme to sustain and succeed. 相似文献
496.
Isotopic evidences for provenance of East Asian Dust 总被引:1,自引:0,他引:1
Jiedong Yang Gaojun Li Wenbo Rao Junfeng Ji 《Atmospheric environment (Oxford, England : 1994)》2009,43(29):4481-4490
We have systematically collected samples in the possible source regions (the deserts and sandy lands of North China, northeastern past of the Tibetan Plateau, Chinese Loess Plateau and southern part of Mongolia) of the East Asian dust. Based on Nd–Sr isotopic ranges, the source regions can be divided into four isotopic regions: Region A1: the Gurbantunggut Desert in Junggar basin and Hunlun Buir sandy land in northeastern China; Region A2: the Hunshandake sandy land, Horqin sandy land and southern part of Mongolia; Region B: the Taklimakan Desert in Tarim basin, northeastern past of the Tibetan Plateau, Chinese Loess Plateau, Badain Jaran Desert and Tengger Desert in Alashan Plateau; Region C: the Hobq Desert and Mu Us Desert in the Ordos Plateau. Through comparison of Nd–Sr isotopes, it can be inferred that the sediments of the north-central Pacific and dust particles in the Greenland ice cores are mainly derived from Region B. Dusts of East Asian dust storm are derived mostly from Region B also, and less from Region A2. The materials of dust storm at Beijing area in April 2006, originated largely from the Hobq Desert and Mu Us Desert in the Ordos Plateau. The floating dust at Beijing area in April 2006, is the mixing of dust of distant deserts and local dust at Beijing area. Loess of the Chinese Loess Plateau may largely originate from Region B. 相似文献
497.
498.
499.
Bala Yerri Swamy Chavidi Venkata Prasad M. N. Prabhakar Kashay Chowdoji Rao M. C. S. Subha Ildoo Chung 《Journal of Polymers and the Environment》2013,21(4):1128-1134
Chitosan-g-poly(methacrylamide) (CS-g-PMAAm) was synthesized by redox polymerization. The synthesized graft copolymers were used to prepare microspheres (MS) by water/oil (W/O) emulsion technique and cross-linked with glutaraldehyde (GA). Developed microspheres were encapsulated using enalapril maleate (ENAM) as a model drug (hypertension) and characterized by fourier transform infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy. The physico-chemical properties of the microspheres were studied by calculating drug entrapment efficiency, and drug release kinetics. % of encapsulation efficiency (% EE) increased with increase in drug loading and methacrylamide (MAAm) content. The minimum % EE (65.2 ± 1.6) was observed in case of microsphere containing 40 % MAAm, 5 % ENAM and 10 mL glutaraldehyde. The release profiles indicate that formulation containing highest (10 mL) crosslinking agent microspheres has the slow release. 相似文献
500.
为研究不同桩芯微型桩在隧道洞口不良地质边坡中的治理效果,拟对钢筋-混凝土、工字钢-混凝土、钢管-钢筋-混凝土、钢管-工字钢-混凝土微型桩开展抗弯极限承载力试验。研究表明,工字钢-混凝土微型桩相比钢筋-混凝土微型桩极限抗弯承载力不仅大幅度提升,其抵抗位移变形的能力也有所增加。钢筋-混凝土微型桩和工字钢-混凝土微型桩桩径由140 mm变化到203 mm,韧性分别提高25%、50%,抗弯承载力分别提高89%、91%。钢管微型桩的韧度、极限抗弯承载力都明显强于裸露混凝土桩,即使变形已非常显著,仍能继续受力。钢管-钢筋-混凝土微型桩、钢管-工字钢-混凝土微型桩桩径由140 mm变化到203 mm,抗弯承载力分别提高近256%、265%。 相似文献