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21.
从世界大河流域开发实践构想长江开发模式 总被引:4,自引:2,他引:2
通过分析世界大河流域开发的多种模式,研究可遵循的客观规律和存在问题。借鉴其经验教训,探讨充分有效开发长江流域的模式。提出“突出重点,综合利用,高效运作,协调发展”的战略思想,力争把长江流域建成我国的一级经济轴线和世界规模最大的现代化沿江产业带。 相似文献
22.
王爱兰 《城市环境与城市生态》2006,(3)
20世纪80年代以来,再生资源产业被许多国家作为战略性产业而得到迅速发展。近年来,我国再生资源产业发展较快,但与发达国家相比还存在较大差距,总结和借鉴发达国家的经验,并提出推进加快产业发展的对策具有重要的现实意义。 相似文献
23.
Is helping a beneficial learning experience for red-cockaded woodpecker (Picoides borealis) helpers?
Several hypotheses have been suggested to explain the evolution and maintenance of helping behavior in cooperatively breeding
birds, one of which we investigated in the red-cockaded woodpecker (Picoides borealis). Helping may provide a learning experience that improves reproductive success once the helper becomes a breeder. We used
data collected from a population of red-cockaded woodpeckers in the Sandhills of North Carolina to compare the reproductive
success of 2-year-old breeders that were helpers at age 1 (helping experience) to those that were floaters or solitary males
at age 1 (no helping experience). Reproductive success of the two groups was similar, indicating that helping provides no
experience useful in reproduction. We reject the learning experience hypothesis as an explanation for the maintenance of helping
behavior in red-cockaded woodpeckers.
Received: 29 July 1996 / Accepted after revision: 27 April 1997 相似文献
24.
Body mass is a consistent individual trait that characterises the state of adult birds and mammals and is positively related
with long-term reproductive success. However, whether and to what extent body mass changes over lifetime in long-lived birds
is poorly studied. In this paper, we investigate how individual body mass varies with age. Furthermore, we try to separate
possible effects of age and experience on body mass. This study was conducted in a Common Tern colony on the German Wadden
Sea coast. Transponders allowed registration of individuals throughout the breeding season and consecutive years with an antenna
system combined with electronic balances for recording individual body-mass changes within and between years. Individual body
masses of males and females were measured during three stages of the breeding season: at arrival, during incubation and chick
rearing when mass was lowest in both sexes. Individual-based longitudinal analyses clearly showed that body mass during arrival,
incubation and chick rearing increased up to an age of 5 or 6 years. First-time breeders had lower body mass than experienced
breeders. Experience had stronger effects on incubation mass than age. Recruiting age also affected body-mass development
of breeders: Three-year-old recruits showed a stronger increase in mass with experience than 4-year-old recruits. We assume
that increasing experience enables birds to cope better with the physiological challenge of reproduction. To explain the general
phenomenon of higher body mass in older birds, our results support the constraint hypothesis rather than either the selection
or restraint hypothesis. 相似文献
25.
旅游体验对旅游者环境态度和环境行为影响的纵向追踪研究 总被引:1,自引:0,他引:1
目前国内关于旅游体验对环境态度和行为影响的纵向追踪研究较为缺乏。论文以自然旅游地黄山为案例地,通过纵向调查,采用配对样本t检验比较同一批次旅游者游前、游后以及3个月后的环境态度和环境行为。研究发现:1)旅游体验对旅游者环境态度基本没有影响。2)旅游体验对旅游者环境行为存在显著影响。短期影响表现为:特定地点环境责任行为中的教育、身体和法律行动显著改善,一般环境责任行为中教育、消费、说服、身体和法律行动显著改善;长期影响表现为:特定地点环境责任行为中的教育、消费、身体行动和一般环境责任行为中的消费、身体、法律行动显著改善。环境行为的改变主要是通过旅游体验中的认知和情感刺激引起的,包括预期愧疚、集体自豪感、环境知识、负面后果认知、自我效能、环境解说等因素。文章最后讨论了管理意义和研究不足。 相似文献
26.
文章从四大方面介绍了新加坡环境保护的主要经验:强烈的环保意识和环境危机感;完备的法律制度、严格的执法手段与高普及度的国民环保教育;健全的机构、合理的规划、高额的投入;有效的政企合作和合理的市场化运作模式;接着总结出对中国的四点启示,以期为中国落实科学发展观、进行生态文明建设及实施环境保护与管理提供参考与借鉴。 相似文献
27.
28.
This paper focuses on the analysis of the possibility of domino effect in underground parallel pipelines relying on historical accident data and pipeline crater models. An underground pipeline can be considered as safe following an accident with an adjacent gas or liquefied pipeline when it remains outside the ground crater generated. In order to prevent the domino effect in these cases, the design of parallel pipelines has to consider adequate pipeline separations based on the crater width, which is one of the widely used methods in engineering applications. The objective of this work is the analysis of underground petroleum product pipelines ruptures with the formation of a ground crater as well as the evaluation of possible domino effects in these cases. A detailed literature survey has been carried out to review existing crater models along with a historical analysis of past accidents. A FORTRAN code has been implemented to assess the performance of the Gasunie, the Batelle and the Advantica crater models. In addition to this, a novel Accident-Based crater model has been presented, which allows the prediction of the crater width as a function of the relevant design pipeline parameters as well as the soil density. Modifications have also been made to the Batelle and Accident-Based models in order to overcome the underestimation of the crater width. The calculated crater widths have been compared with real accident data and the performance evaluation showed that the proposed Accident-Based model has a better performance compared to other models studied in this work. The analysis of forty-eight past accidents indicated a major potential of underground parallel pipelines domino effect which is proven by two real cases taken from the literature. Relying on the investigated accidents, the crater width was smaller than or equal to 20 m in most cases indicating that the definition of underground pipeline separations at around 10 m would be sufficient to ensure a small probability of the domino effect. 相似文献
29.
中国人口基数大、发展水平低、人均资源占有量少的特点以及巨大燃煤量也导致中国环境污染问题愈发严重,决定了中国必须向发展低碳经济转变.中国应通过提高能源使用率,减少资源消耗,开发可再生能源等途径,削弱资源对经济发展的限制.虽然中国的基本国情和发展现状使中国向低碳经济发展转变的难度较大,但是发达国家实施低碳经济转型的实践活动为中国发展低碳经济提供了许多宝贵的经验,让中国发展低碳经济的过程中少走许多弯路,使中国向低碳经济更好的发展. 相似文献
30.