全文获取类型
收费全文 | 241篇 |
免费 | 65篇 |
国内免费 | 11篇 |
专业分类
安全科学 | 108篇 |
废物处理 | 2篇 |
环保管理 | 59篇 |
综合类 | 91篇 |
基础理论 | 16篇 |
污染及防治 | 8篇 |
评价与监测 | 10篇 |
社会与环境 | 4篇 |
灾害及防治 | 19篇 |
出版年
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 13篇 |
2020年 | 5篇 |
2019年 | 13篇 |
2018年 | 10篇 |
2017年 | 19篇 |
2016年 | 19篇 |
2015年 | 9篇 |
2014年 | 21篇 |
2013年 | 14篇 |
2012年 | 29篇 |
2011年 | 17篇 |
2010年 | 10篇 |
2009年 | 11篇 |
2008年 | 8篇 |
2007年 | 10篇 |
2006年 | 7篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1988年 | 2篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有317条查询结果,搜索用时 109 毫秒
11.
12.
13.
Quang M. Nguyen Martha W. Gilliland 《Journal of the American Water Resources Association》1988,24(1):103-111
ABSTRACT: Effects of no-flow river conditions on the quantity and quality of water in the Platte River well field of the City of Grand Island, Nebraska, were examined utilizing a finite-difference computer simulation model specifically developed for this well field. Results suggest that the effects of these no-flow periods on water quality may be most important. In particular, the no-flow periods eliminate the hydraulic barrier between the well field and an area north of the River that is contaminated with nitrate (concentrations in the 20 to 40 mg/1 NO3-N range). They also change the direction and velocity of movement of the contaminated ground water. Simulation results indicate that contaminated ground water moves toward the well field with a velocity of 0.42 ft/d after 30 days of no-flow and 1.43 ft/d after 180 days of no-flow. Limiting no-flow conditions to 10 consecutive days would protect the well field. 相似文献
14.
Water, even in its natural environment, contains some level of impurities. Water is nearly a universal solvent. It contains dissolved solids and gases, and hosts a number of micro-organisms. The exploitation of groundwater by means of boreholes for supplying small user groups and rural communities with water has been widely applied in certain parts of the world for several decades. In recent years this practice has spread all over the globe, and hundred of thousands of boreholes have beendrilled to tap low-yield aquifers. It is evident that such boreholes require pumps for lifting thewater. In developing countries these are usually handpumps, butsolar as well as other systems with submersible pumps are also used, depending upon the energy sources available and the financial means of the beneficiaries. This article gives a general overview of groundwater quality with regard to itsphysico-chemical composition. The results presented originatefrom the experience gained from handpump equipped boreholes within the UNICEF through German Centre for Technical EducationTransfer executed inter-regional UNDP-Handpumps Project inWest African Regions. Particular attention is paid to presenting corrosion onthe water quality of wells in terms of iron concentrationand other parameters. Furthermore, the corrosion attack ongalvanised iron, the effect of biofilms on the corrosionrate, and the difference between internal and externalcorrosion of rising mains are shown. 相似文献
15.
天然气钻井井口安全距离研究分析 总被引:1,自引:0,他引:1
分析天然气钻井井场可能发生的事故类型及事故的破坏程度,选择适合的事故后果模型,对天然气井井喷失控后可能发生的蒸气云爆炸及硫化氢扩散的后果进行量化分析,根据超压-冲量准则、热剂量准则和硫化氢扩散行为规律,计算出爆炸波、爆炸火球及硫化氢扩散的危害范围。笔者建立了天然气钻井井口安全距离的计算模型,并提出一种确定安全距离的方法。通过计算给出不同无阻流量、不同硫化氢体积含量的20种条件下的天然气钻井井口安全距离,并应用该模型对某含硫气井井口安全距离进行了计算。实例表明,该方法具备实用性,值得在天然气井选址规划中推广和使用。 相似文献
16.
Peter G. Ashton James B. Pickens Coryell Ohlander Bruce Benninghoff 《Journal of the American Water Resources Association》1980,16(4):738-744
ABSTRACT: Decisionmaking associated with the Nation's 1.7 billion acres of forest and range land has become increasingly complicated because of the rise in competition for resource use and in the awareness of environmental and social effects. This system analysis approach uses four models to synthesize pertinent masses of information into measures of economic, environmental, and social impacts. The system results can be used to help evaluate alternative national programs. The models are:
17.
Guha, Hillol and Sorab Panday, 2012. Impact of Sea Level Rise on Groundwater Salinity in a Coastal Community of South Florida. Journal of the American Water Resources Association (JAWRA) 48(3): 510-529. DOI: 10.1111/j.1752-1688.2011.00630.x Abstract: Freshwater resources of coastal communities in the United States and world over are threatened by the rate of sea level rise. According to recent estimates by various governmental agencies and climate researchers, the global sea level rise is likely to be between 0.6 and 2.1 m by the year 2100. South Florida is a coastal community and much of its coastline is subject to sea level rise and potential impacts to wetlands and the water resources of the area. To understand what the impact of sea level rise would cause to the groundwater level and salinity intrusion, an integrated groundwater and surface water model was developed for North Miami-Dade and Broward Counties of South Florida. The model was calibrated against daily groundwater heads, base flows in canals, and chloride concentrations for a period of one year and six months. Three separate sensitivity analyses were conducted by increasing the sea level by 0.6, 0.9, and 1.22 m. Results of the simulations shows increase of groundwater heads in some areas from 4 to 15%; whereas the average relative chloride concentrations increased significantly by 100-600% in some wells. The increase in groundwater elevations and chloride concentrations varies from location of the wells and its proximity to the coast. The model results indicate that even a 0.6 m increase in sea level (which is the conservative estimate) is likely to impair the vital freshwater resources in many parts of South Florida. 相似文献
18.
抽汲排液存在抽汲设备和工具密封性差,对井场环境污染比较严重的问题,为解决抽汲排液对井场造成的污染,分别对抽汲钢丝绳的选择、试油井口防喷盒的密封以及试油抽汲作业规程及其它方面作了研究和应用,使抽汲排液对井场造成的污染得到了较好控制,符合新疆油田创建"绿色油气田"的要求。 相似文献
19.
20.
Junpei Tomita Hiroshi Satake Keiichi Sasaki Masayoshi Yamamoto 《Journal of environmental radioactivity》2010,101(3):201-210
Radium isotopes in 23 Na-Cl type groundwater sampled mainly from deep wells in Niigata Prefecture, which is the site of the largest oil- and gas-fields in Japan, were measured along with U isotopes, chemical components and hydrogen and oxygen isotope ratios to elucidate the distribution and behavior of Ra in a brackish environment underground. Also analyzed were U and Th isotopes in 38 rock samples collected from outcrops at 17 locations. Ra-226 concentrations (8.86-1637 mBq kg−1) of groundwater samples roughly correlated with total dissolved solid (TDS) concentrations and other alkaline earth contents. Their 228Ra/226Ra activity ratios (0.32-5.2) were similar to or higher than the 232Th/238U activity ratios (0.6-1.7) in the rocks. The most likely transport mechanism of Ra isotopes into groundwater was due to their α-recoil from the solid phase, probably from the water-rock interface where Th isotopes had accumulated, and adsorption/desorption reaction based on the increase in 226Ra contents with TDS. 相似文献