首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   85篇
  免费   3篇
  国内免费   3篇
安全科学   2篇
环保管理   43篇
综合类   30篇
基础理论   1篇
污染及防治   2篇
评价与监测   7篇
社会与环境   6篇
  2021年   2篇
  2019年   2篇
  2018年   1篇
  2017年   2篇
  2016年   1篇
  2015年   1篇
  2014年   6篇
  2013年   1篇
  2012年   6篇
  2011年   7篇
  2010年   7篇
  2009年   4篇
  2007年   3篇
  2006年   11篇
  2005年   5篇
  2004年   1篇
  2003年   2篇
  2002年   3篇
  2001年   3篇
  2000年   4篇
  1999年   2篇
  1998年   2篇
  1997年   3篇
  1996年   2篇
  1995年   2篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1989年   2篇
  1987年   1篇
  1986年   1篇
  1981年   1篇
排序方式: 共有91条查询结果,搜索用时 286 毫秒
81.
旅游度假区环境影响的经济分析   总被引:2,自引:1,他引:2  
以岳阳南湖旅游度假区为产例,探讨了旅游度假区环境影响的费用效益分析方法,分析时以旅游度假区的环境保护设施建设费及其运行费作为环保费用,以采取环保措施后可避免的旅游业,渔业,房地产业等的污染损失作为环保效益,根据社会折现率折算成现值进行比较。  相似文献   
82.
随着湖南省柳子景区的开发,游客的"场所依恋"水平呈缓慢上升的趋势,说明景区开发对场所依恋有着正向的影响。在景区开发过程中,个人感情和从业者的行为与态度两个影响因素对场所依恋的贡献较小,景观质量、知名度和旅游环境在短时间内得到了迅速的提升和改善,从而导致游客场所依恋水平增加,且前期的增幅要超过后期,显得后劲不足。湖南省柳子景区未来应当挖掘场所认同,强化与游客的感情联系,并注意持续扩大该景区的知名度,提高从业者的素质,用以促进游客"场所依恋"水平的提升。  相似文献   
83.
Incorporation of aesthetic considerations in the process of landscape planning and development has frequently met with poor results due to its lack of theoretical basis, public involvement, and failure to deal with spatial implications. This problem has been especially evident when dealing with large areas, for example, the Adirondacks, Scenic Highways, and National Forests and Parks. This study made use of public participation to evaluate scenic quality in a portion of the Niagara Escarpment in Southern Ontario, Canada. The results of this study were analyzed using thevisual management model proposed by Brown and Itami (1982) as a means of assessing and evaluating scenic quality. Themap analysis package formulated by Tomlin (1980) was then applied to this assessment for the purpose of spatial mapping of visual impact. The results of this study illustrate that it is possible to assess visual quality for landscape/management, preservation, and protection using a theoretical basis, public participation, and a systematic spatial mapping process.  相似文献   
84.
银厂沟风景区旅游环境质量评价   总被引:4,自引:0,他引:4       下载免费PDF全文
为正确评估风景区的旅游资源,确定其深度开发的意义,保持生态环境、从旅游环境容量、旅游区级别、旅游资源的综合价值3方面对银厂沟风景区的旅游环境质量进行了评价。结果表明,银厂沟风景区属于省级旅游地,具有一定的潜在开发意义。指出,在旅游高峰期,该风景区的环境容量超标,产生了游客食宿不便、景区观赏点不足、设施损坏、环境负荷加重等问题,应引起旅游管理部门的重视。  相似文献   
85.
基于双龙风景区自驾车游客的实地问卷调查资料,得出双龙风景区自驾车游客的客源地构成;分析了自驾车游客的年龄、职业、收入等结构特征及其出游时间、旅游偏好、消费水平等行为特征;揭示了制约自驾车游客出游的主要因素;针对自驾车游客的旅游体验与评价,提出了促进自驾车旅游发展的建议,以期为相关旅游企业及旅游管理部门的决策提供参考依据。  相似文献   
86.
黄山自然风景保护区自然条件优越,森林植被垂直分布明显,种子植物丰富,有134科655属1483种,其中国家重点保护植物有31种.由于旅游的发展,种子植物多样性受到威胁,应加强种子植物的保护.  相似文献   
87.
Three studies used digital color photographs to compare responses to natural scenes, skylines after dark, and skylines during the day (seven of each). Study 1 had 59 respondents rate the pleasantness of each scene. They gave similar ratings to Night Skylines and Natural Scenes, and rated each as more pleasant than the Day Skylines. Study 2 had 56 other participants choose from each of seven sets of each kind of scene the one they would most like to have as a framed print in their home or office, and to report the reasons. Participants chose Night Skylines most often, followed by Natural Scenes and then Day Skylines. While participants most often picked attractive as a reason for their choice, those who chose Night Skylines also picked exciting as the reason, and those who picked Natural Scenes also picked relaxing or peaceful as a reason. Study 3 obtained ratings of selected formal features of each scene. The 23 judges rated the Natural scenes as more natural, orderly, open, and curvilinear, less complex, and as having smoother transitions than either Day or Night Skylines; and they judged the Night Skylines as higher in complexity but lower in order than Day Skylines. The results suggest that preferences in relation to the scene categories may well depend on a mix of their formal characteristics and their content.  相似文献   
88.
黄山风景区悬钩子属植物资源及其开发利用   总被引:1,自引:0,他引:1  
黄山风景区共有悬钩子属植物20种5变种。记述了该地区悬钩子属植物资源的种类、分布及价值,并对其合理开发利用提出了建议,为生态旅游和经济发展提供参考。  相似文献   
89.
A rotating anvil similar to a pinless friction stir welding (FSW) tool can be applied to friction stir spot welding (FSSW) of thin metal plates. FSSW is a solid-state joining process that is currently being used by automotive manufacturers as an alternative to rivets and traditional resistance spot welding. The principal detractor of this process is the keyhole left by pin extraction, which can be detrimental to the weld strength. A pinless tool can be used to eliminate the keyhole. However, this approach is limited to joining thin sheet (≤1 mm). Using a rotating anvil with the FSSW process permits the joining of thicker cross sections, improves the mechanical strength of the spot weld and reduces the reaction forces on the spot welding frame. A numerical model of the process, tensile shear tests and macrosection analysis are used to evaluate the spot welds.Macrosection and numerical analysis reveals that the material flow between the pinless tool and rotating anvil is complex and unique to this process. It has been found that the use of a rotating anvil for FSSW is a viable means to create quality spot welds in thicker weldments.  相似文献   
90.
Kiso Y  Jung YJ  Kuzawa K  Seko Y  Saito Y  Yamada T  Nagai M 《Chemosphere》2006,64(11):1949-1954
A spot test for aqueous nitrate and nitrite for controlling nitrogen removal performance in small-scale wastewater treatment facilities is proposed. In this method, NO(2)(-) ion in water samples was allowed to react with sulfanilic acid and 1-naphthol to form an anionic azo dye. The resulting colored solution was introduced onto a mini column (similar to a gas detecting tube) packed with PVC particles coated with benzyl cetyl dimethyl ammonium chloride (BCDMA) and biphenyl. The NO(2)(-)-N concentration was determined visually by measuring the color band length (CBL) in the column. The CBL correlates linearly with nitrite concentration in the 4-20 mg-N l(-1) range. The concentration of nitrite+nitrate was determined after reduction to nitrite with zinc. The concentration of NO(3)(-)-N species was calculated by difference. This method was used to visually determine the concentrations of NO(2)(-)-N and (NO(2)(-)+NO(3)(-))-N in domestic wastewater samples with maximum suspended solid (SS) and chemical oxygen demand (COD) concentrations of 114 mg l(-1) and 73.9 mg l(-1), respectively.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号