全文获取类型
收费全文 | 7350篇 |
免费 | 48篇 |
国内免费 | 54篇 |
专业分类
安全科学 | 209篇 |
废物处理 | 422篇 |
环保管理 | 606篇 |
综合类 | 1115篇 |
基础理论 | 1669篇 |
环境理论 | 1篇 |
污染及防治 | 1976篇 |
评价与监测 | 580篇 |
社会与环境 | 839篇 |
灾害及防治 | 35篇 |
出版年
2023年 | 71篇 |
2022年 | 142篇 |
2021年 | 135篇 |
2020年 | 66篇 |
2019年 | 75篇 |
2018年 | 156篇 |
2017年 | 168篇 |
2016年 | 214篇 |
2015年 | 129篇 |
2014年 | 239篇 |
2013年 | 600篇 |
2012年 | 295篇 |
2011年 | 377篇 |
2010年 | 312篇 |
2009年 | 300篇 |
2008年 | 363篇 |
2007年 | 345篇 |
2006年 | 345篇 |
2005年 | 294篇 |
2004年 | 248篇 |
2003年 | 253篇 |
2002年 | 207篇 |
2001年 | 265篇 |
2000年 | 167篇 |
1999年 | 112篇 |
1998年 | 48篇 |
1997年 | 62篇 |
1996年 | 58篇 |
1995年 | 65篇 |
1994年 | 69篇 |
1993年 | 61篇 |
1992年 | 60篇 |
1991年 | 65篇 |
1990年 | 70篇 |
1989年 | 53篇 |
1988年 | 61篇 |
1987年 | 56篇 |
1986年 | 58篇 |
1985年 | 44篇 |
1984年 | 49篇 |
1983年 | 49篇 |
1982年 | 48篇 |
1980年 | 30篇 |
1979年 | 33篇 |
1978年 | 29篇 |
1977年 | 28篇 |
1976年 | 28篇 |
1974年 | 32篇 |
1973年 | 30篇 |
1972年 | 28篇 |
排序方式: 共有7452条查询结果,搜索用时 453 毫秒
981.
234U and 230Th determination by FIA-ICP-MS and application to uranium-series disequilibrium in marine samples 总被引:1,自引:0,他引:1
Godoy ML Godoy JM Kowsmann R Dos Santos GM Petinatti da Cruz R 《Journal of environmental radioactivity》2006,88(2):109-117
A 234U and 230Th determination method based on an extraction chromatographic separation on a flow injection system coupled to a quadruple ICP-MS was developed. Two-milliliter UTEVA (Eichrom Co.) cartridges were applied as separation tool and 236U and 229Th as spikes. Loading and washing steps were carried out in 3 M HNO3 solution and 0.05 M ammonium oxalate applied to elute both uranium and thorium. The method was applied initially to the IAEA-327 soil reference sample and NIST SRM 4357 ocean sediment reference material, with the obtained 234U and 230Th concentrations in agreement with the reference levels. Samples from a deep-sea sediment core (2450 m water depth) were analyzed and based on 230Th/234U dating, a mean sedimentation rate of 3.3 cm ky(-1) was calculated. Samples from two sediment layers were also dated by 14C-AMS and the observed ages agree with the 230Th/234U results. 相似文献
982.
Sheppard SC Sheppard MI Tait JC Sanipelli BL 《Journal of environmental radioactivity》2006,89(2):115-137
There is a continual supply of new experimental data that are relevant to the assessment of the potential impacts of nuclear fuel waste disposal. In the biosphere, the traditional assessment models are data intensive, and values are needed for several thousand parameters. This is augmented further when measures of central tendency, statistical dispersion, correlations and truncations are required for each parameter to allow probabilistic risk assessment. Recent reviews proposed values for 10-15 key element-specific parameters relevant to (36)Cl, (129)I, (222)Rn, (226)Ra, (237)Np and (238)U, and some highlights from this data update are summarized here. Several parameters for Np are revised downward by more than 10-fold, as is the fish/water concentration ratio for U. Soil solid/liquid partition coefficients, Kd, are revised downward by 10-770-fold for Ra. Specific parameters are discussed in detail, including degassing of I from soil; sorption of Cl in soil; categorization of plant/soil concentration ratios for U, Ra and Np; Rn transfer from soil to indoor air; Rn degassing from surface water; and the Ca dependence of Ra transfers. 相似文献
983.
Purvis OW Longden J Shaw G Chimonides PD Jeffries TE Jones GC Mikhailova IN Williamson BJ 《Journal of environmental radioactivity》2006,90(2):151-162
Multi-element content and uranium (U) isotopes were investigated in the lichen Hypogymnia physodes (native and transplants) sampled across a 60-km transect, centred on Karabash smelter town, from Turgoyak Lake (SW) to Kyshtym (NE) to investigate the origin of U. Kyshtym was the site of a major nuclear accident in 1957. (234)U/(238)U activity ratios in native thalli sampled during July 2001 were within the natural isotopic ratio in minerals. Uranium/thorium (U/Th) ratios were higher in native thalli towards the NE (average 0.73) than those in the SW (average 0.57). Element signatures in native thalli and transplants suggest U was derived from fossil fuel combustion from Karabash and sources lying further to the east. Systematic and significant U enrichment indicative of a nuclear fuel cycle source was not detected in any sample. Element signatures in epiphytic lichen transplants and native thalli provide a powerful method to evaluate U deposition. 相似文献
984.
I-Risk: development of an integrated technical and management risk methodology for chemical installations 总被引:1,自引:0,他引:1
I. A. Papazoglou L. J. Bellamy A. R. Hale O. N. Aneziris B. J. M. Ale J. G. Post J. I. H. Oh 《Journal of Loss Prevention in the Process Industries》2003,16(6):575-591
This paper presents an integrated quantitative risk assessment method for hazardous installations, taking into account management as well as technical design and producing risk level measures. The key components of the I-Risk methodology are the technical model, the management model and their interface. The technical model consists of developing a master logic diagram (MLD) delineating the major immediate causes of loss of containment (LOC) and associated quantitative models for assessing their frequency. The management model consists of the tasks, which must be carried out systematically in the primary business functions (such as operations, emergency operations, maintenance and modifications). A management audit quantifies the quality of these management tasks. The management–technical interface modifies certain parameters of the technical model on the basis of the quality of the safety management system of the specific installation. The methodology is exemplified through its application to the risk assessment of an ammonia storage facility. A detailed technical model simulating the response of the system to various initiating events is developed along with a detailed management model simulating the influence of the plant-specific management and organisational practices. The overall effect is quantified through the frequency of release of ammonia as a result of a loss of containment in a storage tank and in a pipeline. 相似文献
985.
Effective environmental management through life cycle assessment 总被引:6,自引:0,他引:6
F. I. Khan V. Raveender T. Husain 《Journal of Loss Prevention in the Process Industries》2002,15(6):455-466
Unplanned and unsustainable development (particularly rapid industrialisation) has placed great pressure in every dimension of the environment (air, water, soil, health, etc.). The resulting disturbance in the natural ecological balance is a serious concern. Sustainable development is the need of the hour; it can only be achieved through effective environmental management. Environmental management will become indispensable in the future as regulatory restrictions tighten and public expectations of environmental performance increase. The day is not far away when a customer will prefer to buy products produced by an environmentally committed organisation. In short, the environmental commitment of an organisation will become a market strategy.
Environmental management is a set of actions based on a structured methodology to ensure that an organisation is committed to the environment and that the production process has minimal/no adverse affect on it. This article emphasises environmental management in the real engineering sense of the term, and discusses how to develop an effective environmental management system through life cycle assessment. It further demonstrates through a real life case study how an industry has achieved landmark success in managing its environment, production, as well as winning the good faith of society. 相似文献
986.
在关于改善环境的科学与政策讨论中,最经常提到的话题之一就是如何使小型和中等规模的企业参与进来. 相似文献
987.
Mimi H. Hassim Markku Hurme Paul R. Amyotte Faisal I. Khan 《Journal of Loss Prevention in the Process Industries》2012,25(5):820-829
Fugitive emissions are among the major concerns of industrial process releases. The emissions cause problem to various aspects including the environment, health, and economic. Early evaluation of process hazards is beneficial because process can be made inherently benign at lower cost. This paper discusses two important aspects of fugitive emissions assessment during process design – the quantification and the prevention strategies.For the quantification part, three methods are presented for fugitive emissions estimation during the process design. They are tailored to data available in simple process flow diagram (PFD), detailed PFD, and piping & instrumentation diagram (PID). Such methods are needed as early emissions estimation allows production routes and process designs with lower emissions to be selected. The fugitive emissions estimation and methods to abatement are demonstrated on a benzene process case study. Valves are found to be the major emission source with 50% of fugitive emissions of process area in a base case of petrochemical process, in which no fugitive emission reductions are yet made. Pumps without mechanical seals come second with 30% and flanges with 8% of emissions. Inherently safer design keywords can be applied to prevent fugitive emissions in the process plants. Substitution is the most applicable keyword in fugitive emission reduction of existing plants.The emission rate calculations together with estimation of health risk give a sound background for the decision making on elimination of emissions at source through equipment and piping changes. The case study presented reveals that by substituting emission prone components by inherently low-leaking ones, the plant emissions can be reduced over 90% in practice. This is created mainly by replacing rising stem valves with ball valves, installing double mechanical pump seals or hermetic pumps and making changes in sampling and relief systems. Ideally by also changing flanges to welded connections, which is not viable for various reasons, the emissions could be reduced nearly to zero. 相似文献
988.
Alba Pineda-Solano Lina Saenz-Noval Subramanya Nayak Simon Waldram Maria Papadaki M. Sam Mannan 《Process Safety and Environmental Protection》2012,90(5):404-410
Alkylpyridine N-oxides are important intermediates in the pharmaceutical and agrochemicals industries. The N-oxides are produced via the homogeneously catalyzed oxidation of the respective alkylpyridines using a 50% excess of hydrogen peroxide. The competitive hydrogen peroxide decomposition produces oxygen in the flammable environment of alkylpyridines and thus forms a key hazard for this reaction. In this work, the N-oxidation was performed under pressure in the temperature range of 110–125 °C with different catalyst concentrations. It was shown that temperature had an undisputable positive effect on the N-oxidation efficiency. The accurate measurement of the pressure rise due to decomposition was difficult. However, only 5% of the added H2O2 decomposed when stoichiometric quantities were employed, even in the temperature of 110 °C. The N-oxidation was very efficient, even when the lowest concentration of catalyst employed in this study was used. 相似文献
989.
Shimabukuro VG Alexandre NM Coluci MZ Rosecrance JC Gallani MC 《International journal of occupational safety and ergonomics》2012,18(1):15-26
Physical therapists engage in work tasks that expose them to occupational risk factors related to musculoskeletal disorders. Due to the gap in the literature on instruments focused on those workers, this study adapted a job factors questionnaire to physical therapists, and assessed its psychometric properties. The questionnaire was adapted and its content validity was established. The psychometric properties were evaluated among 142 physical therapists. Reliability was verified using the temporal-stability design and internal consistency. Construct validity was assessed with the known-groups technique. Test-retest results demonstrated intraclass correlation coefficients between .82 and .90 (p < .001). Cronbach's α of .91 verified the reliability of the questionnaire. The known-groups technique demonstrated a statistically significant difference on the scores of the items when physical therapists were compared to office workers. The results indicated that the adapted questionnaire had acceptable psychometric properties for assessing problematic job factors among physical therapists working in hospitals. 相似文献
990.
Perceived changes in well-being and happiness with gardening in urban organic allotments in Portugal
Urban allotment gardens (AG) in Portugal have increased in recent years, as in many other European countries and worldwide. The contribution of these gardens to the happiness and well-being of urban populations has been recognized, but evaluations of their benefits are still very scarce. The objective of this study was to evaluate this contribution, based on the urban organic AG of the Devesa Park in Vila Nova de Famalicão, Portugal. The sample included 65 gardeners who completed the self-administered questionnaires of Bem-Estar Pessoal (personal well-being scale), Felicidade Subjetiva (subjective happiness scale) and sociodemographic characteristics. Respondents were mainly adults under 65 years, married and academically well qualified and about half of them had a professional activity, with nearly one third being retired. They considered themselves happy with their life (Personal Well-being Index = 74.5%) and revealed an optimistic and positive attitude towards life, regardless of economic or social difficulties. The increased frequency of visits for gardening was positively related to a greater perception of subjective happiness. The gardeners who visited the AG more frequently considered themselves happier from a self-perspective and in comparison with peers. It can be suggested that urban organic AG represent a means for enhancing citizen well-being, contributing positively to their feelings of happiness and life satisfaction, changing behaviours and developing personal capacities. Beyond economic measures, urban AG can be recommended to capture the well-being of societies. 相似文献