全文获取类型
收费全文 | 1904篇 |
免费 | 117篇 |
国内免费 | 197篇 |
专业分类
安全科学 | 103篇 |
废物处理 | 24篇 |
环保管理 | 507篇 |
综合类 | 751篇 |
基础理论 | 229篇 |
污染及防治 | 42篇 |
评价与监测 | 31篇 |
社会与环境 | 442篇 |
灾害及防治 | 89篇 |
出版年
2024年 | 8篇 |
2023年 | 36篇 |
2022年 | 34篇 |
2021年 | 59篇 |
2020年 | 44篇 |
2019年 | 41篇 |
2018年 | 45篇 |
2017年 | 80篇 |
2016年 | 82篇 |
2015年 | 74篇 |
2014年 | 55篇 |
2013年 | 118篇 |
2012年 | 145篇 |
2011年 | 157篇 |
2010年 | 122篇 |
2009年 | 85篇 |
2008年 | 82篇 |
2007年 | 117篇 |
2006年 | 119篇 |
2005年 | 88篇 |
2004年 | 71篇 |
2003年 | 64篇 |
2002年 | 66篇 |
2001年 | 42篇 |
2000年 | 41篇 |
1999年 | 35篇 |
1998年 | 42篇 |
1997年 | 36篇 |
1996年 | 18篇 |
1995年 | 30篇 |
1994年 | 21篇 |
1993年 | 20篇 |
1992年 | 23篇 |
1991年 | 8篇 |
1990年 | 12篇 |
1989年 | 4篇 |
1988年 | 9篇 |
1983年 | 5篇 |
1982年 | 12篇 |
1981年 | 4篇 |
1980年 | 9篇 |
1979年 | 11篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 7篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 7篇 |
排序方式: 共有2218条查询结果,搜索用时 718 毫秒
211.
环境约束下长江经济带全要素能源效率的时空分异研究——基于超效率DEA模型和ML指数法 总被引:1,自引:0,他引:1
基于超效率DEA模型和ML指数法,考察长江经济带1999~2013年全要素能源效率。实证研究结果显示:研究期内,环境约束下的长江经济带全要素能源效率年均下降2.9%,而不考虑环境因素的全要素能源效率年均下降幅度仅为0.4%,污染是导致能源效率损失的重要因素;长江经济带整体层面全要素能源效率的发展演变基本呈"双峰一谷"的"M"形分布,表现为两个"上升—下降"周期,而省际和上中下游全要素能源效率的演变特征迥异;从空间差异看,省际全要素能源效率差异远远大于上中下游差异,但近年来这种差异均有不同程度的缩小。未来长江经济带发展必须践行生态文明发展战略,保证发展的可持续性,同时加强能源、环保等领域的合作,促进长江经济带全要素能源效率发展的协同进步。 相似文献
212.
Eric K.W. Aikins 《Natural resources forum》2014,38(4):261-269
Geography provides the basic building blocks for the study of resource use and sustainable development, inasmuch as it categorizes the human environment. Within the environment are resources that are needed for the survival of society. As resources are largely limited and finite, humans as agents of change must employ techniques that allow an efficient and lasting use of the available resources in their environment. This paper discusses the nexus between geography, resource exploitation, use, and sustainable development. It also discusses the characteristics, types, and classification of resources, development and sustainable development as well as the challenges and strategies for attaining sustainable development, particularly in developing countries. 相似文献
213.
采用田间试验方法研究了控释尿素不同施用条件对冬小麦产量、氮素利用和经济效益的影响。试验共设7个处理,即CK (空白处理,不施氮肥)、100%PU10/0(普通尿素全量基施,N 240 kg·hm-2)、100%PU6/4(60%的普通尿素基施、40%的普通尿素于拔节期追施,N 240 kg·hm-2)、80%PU6/4(60%的普通尿素基施、40%的普通尿素于拔节期追施,N 192 kg·hm-2)、100%CRU(全量树脂包膜控释尿素基施,N 240 kg·hm-2)、80%CRU(80%树脂包膜控释尿素基施,N 192 kg·hm-2)和40%CRU+40%PU(40%树脂包膜控释尿素+40%的普通尿素基施,N 192 kg·hm-2)。结果表明,无论是产量效应还是氮素利用效应,树脂包膜控释尿素(CRU)处理总体优于普通尿素(PU)处理,尤其树脂包膜控释尿素和普通尿素配施(40%CRU+40%PU)效果最佳,以7709 kg·hm-2的产量、36.44%的氮肥吸收利用率、15946元·hm-2的相对净收入达到处理间最高水平。该处理在减少氮素投入量的情况下,不仅促进了冬小麦增产,而且显著提高了肥料的利用率,拥有较高的产投比。因此,树脂包膜控释尿素和普通尿素的配施处理(40%CRU+40%PU)是本试验条件下最优的氮肥处理。 相似文献
214.
文中总结宿迁经济开发区环保工作现状,分析未来宿迁经济开发区面临:水环境质量未能根本好转、生活污染物排放量上升并成为主要污染问题、环境基础设施建设滞后于社会经济发展、工业企业污染存在反弹趋势、农村环境问题亟需关注、客水污染问题仍然存在等挑战,并提出了应对这些挑战的对策。 相似文献
215.
In 1996 the Swedish Poisons Information Centre performed a follow-up study concerning poisonings related to ‘do-it-yourself’ activities. The study was supported by the National Institute of Public Health in Sweden. The objectives were to investigate and define monthly variations, route of exposure, type of products and, in particular, exposures to corrosives, age and sex groups, place of treatment, severity of symptoms, place of the accident, special risk products and risk situations. The Poisons Information Centre was contacted concerning 1609 cases, with a peak during the summer months. There was no or uncertain connection between exposure and symptoms in 117 cases. This means that 1492 cases were left to study. Inhalation and eye exposure were the predominant routes, followed by skin exposure and ingestion. Cleaning agents were the most common type of products involved. Of the 1492 cases included in the study 1033 were possible to follow up. Among these, 20–29 year olds and 30–39 year olds predominated, and there was a dominance for men. In total, 28% of those exposed were subject to medical attention, either in hospital or in outpatient clinics. According to the Poisoning Severity Score 78% had mild (grade 1) and 7% moderate (grade 2) symptoms. There were no severe intoxications and no deaths. Severity grade 2 occurred 3.6 times more often among those with exposures involving risk of corrosive damage than among others in the study population. Most accidents occurred in the home. Special risk products and risk situations were exposure to corrosive products, release of chlorine when mixing hypochlorite and acid, ‘fire-eating’, siphoning gasoline and diesel fuel, welding, and inhalation of carbon monoxide from exhaust gases. The Swedish Poisons Information Centre registered 1609 cases of poisoning accidents during ‘do-it-yourself’ activities, which means an average of four to five cases per day. Although this type of accidents is not uncommon, significant poisoning seems to be rare. Some special risk situations were identified. 相似文献
216.
Abstract: Hydrothermal vents are deep‐sea ecosystems that are almost exclusively known and explored by scientists rather than the general public. Continuing scientific discoveries arising from study of hydrothermal vents are concommitant with the increased number of scientific cruises visiting and sampling vent ecosystems. Through a bibliometric analysis, we assessed the scientific value of hydrothermal vents relative to two of the most well‐studied marine ecosystems, coral reefs and seagrass beds. Scientific literature on hydrothermal vents is abundant, of high impact, international, and interdisciplinary and is comparable in these regards with literature on coral reefs and seagrass beds. Scientists may affect hydrothermal vents because their activities are intense and spatially and temporally concentrated in these small systems. The potential for undesirable effects from scientific enterprise motivated the creation of a code of conduct for environmentally and scientifically benign use of hydrothermal vents for research. We surveyed scientists worldwide engaged in deep‐sea research and found that scientists were aware of the code of conduct and thought it was relevant to conservation, but they did not feel informed or confident about the respect other researchers have for the code. Although this code may serve as a reminder of scientists’ environmental responsibilities, conservation of particular vents (e.g., closures to human activity, specific human management) may effectively ensure sustainable use of vent ecosystems for all stakeholders. 相似文献
217.
Based on the analysis on the global economic crisis,climate change crisis and their mutual underlying reasons,the authors believe that low-carbon economy has become an inevitable choice to break through the dual crises,coordinate the economic development,and protect the global climate.The global trend of low-carbon economy finds expression in Green Recovery currently,while,in a long run,it will give rise to a new pattern of world competition in politics,economy,technology,trade and finance.The impact of the... 相似文献
218.
Duan Pingzhong 《China Population Resources and Environment》2008,18(5):27-33
In this study, an econometric model about population mobility and economic growth is used to show the unbalanced distribution of population mobility in different region was remarkably related to that of regional economic growth and the large number of movers had a significant influence on regional economic growth and developing disparity. On the basis of this study, we conclude that China's population mobility also had a significant influence on the structure and tendency of regional disparity, and the population mobility enlarged the regional disparity of the whole nation, the East, and the West since the reform, besides the Midst during 1978 to 1987. Furthermore, the population mobility accelerated the increase of regional disparity in the whole nation, the Midst, and the West, but at the same time, retarded that in the East in the period of 1996–2003. 相似文献
219.
珠江上游少数民族县域经济活动的累积环境效应研究--以贵州三都水族自治县为例 总被引:1,自引:0,他引:1
为了探索珠江上游少数民族区域经济活动的累积环境效应与生态安全,我们选择三都水族自治县作为定位研究基地.对建国以来区域内经济活动变迁进行历史、现状研究和综合评估,揭示历史时期发展政策、发展模式、重大经济活动等人为扰动因素在区域生态环境系统退化过程中的作用.评估少数民族经济活动的累积环境效应与生态安全。 相似文献
220.
文章介绍了一种能耗低、效率高、快速生产臭氧的新装置。文中对该装置的工作原理、臭氧的生产过程、影响臭氧产率的因素以及该装置的特点等进行了简要介绍。 相似文献