全文获取类型
收费全文 | 1183篇 |
免费 | 54篇 |
国内免费 | 142篇 |
专业分类
安全科学 | 48篇 |
废物处理 | 60篇 |
环保管理 | 106篇 |
综合类 | 379篇 |
基础理论 | 294篇 |
污染及防治 | 321篇 |
评价与监测 | 71篇 |
社会与环境 | 77篇 |
灾害及防治 | 23篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 59篇 |
2021年 | 37篇 |
2020年 | 49篇 |
2019年 | 38篇 |
2018年 | 41篇 |
2017年 | 50篇 |
2016年 | 69篇 |
2015年 | 54篇 |
2014年 | 83篇 |
2013年 | 92篇 |
2012年 | 77篇 |
2011年 | 96篇 |
2010年 | 55篇 |
2009年 | 68篇 |
2008年 | 67篇 |
2007年 | 53篇 |
2006年 | 49篇 |
2005年 | 39篇 |
2004年 | 32篇 |
2003年 | 35篇 |
2002年 | 30篇 |
2001年 | 27篇 |
2000年 | 20篇 |
1999年 | 12篇 |
1998年 | 9篇 |
1996年 | 10篇 |
1995年 | 9篇 |
1994年 | 11篇 |
1993年 | 7篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 4篇 |
排序方式: 共有1379条查询结果,搜索用时 15 毫秒
991.
Nicolas Le Corre Ingrid Peuziat Louis Brigand Guillaume Gélinaud Catherine Meur-Férec 《Environmental management》2013,52(4):780-791
Disturbance to wintering birds by human recreational activities has become a major concern for managers of many natural areas. Few studies have examined how recreationists perceive their effects on birds, although this impacts their behavior on natural areas. We surveyed 312 users on two coastal ornithological sites in Brittany, France, to investigate their perception of the effects of human activities on wintering birds. The results show that the awareness of environmental issues and knowledge of bird disturbance depends on the socioeconomic characteristics of each user group, both between the two sites and within each site. Results also indicate that, whatever the site and the user group, the vast majority of the respondents (77.6 %) believed that their own presence had no adverse effects on the local bird population. Various arguments were put forward to justify the users’ own harmlessness. Objective information on recreationists’ awareness of environmental issues, and particularly on their own impact on birds, is important to guide managers in their choice of the most appropriate visitor educational programs. We recommend developing global but also specific educational information for each type of user to raise awareness of their own impact on birds. 相似文献
992.
The scale, duration and intensity of conflicts over mineral resources vary greatly. However, they always involve, in varying proportions, the triad stakeholder model—corporation, state, community—each element of which is internally heterogeneous. Increasingly, new players are entering the scene: international non-governmental organizations (NGOs), environmental grassroots groups, indigenous transnational networks, international aid and development agencies. Nevertheless, conflicts and arrangements around access to and control over mineral resources can take the apparent form of dyadic relationships between companies and local communities, resulting in negotiated company-community agreements, often called “Impact and Benefit Agreements” (IBAs). In our analysis, local agreements on mineral resource governance are seen as building blocks in the production of mining policy “from below”, even though they seem at first sight to exclude the state. This paper argues that these agreements, and the negotiations surrounding them, inform debates around mining through both “horizontal diffusion” (influence on other localities facing similar situations) and “vertical diffusion” (influence on policy design and implementation at upper political and administrative levels). This diffusion may occur in a “positive” sense, effecting further change in line with the intent of the original agreement, or in a “negative” one, actually making substantive change less likely, whether at a community or policy level. We build this argument through two case studies from New Caledonia, in the south-west Pacific, where mining has long been a key issue, especially in the current context of “negotiated decolonization” launched by the 1998 Nouméa Accord. 相似文献
993.
Alain Delisle Micheline Gagnon Pierre Desjardins 《International journal of occupational safety and ergonomics》2013,19(2):109-118
The purpose of this study was to evaluate the effect of four handgrip/box tilting strategies (right, left, backward, and no tilt of the box) on trunk and knee efforts, body posture, and the stability of 14 participants with limited experience in handling. The tasks consisted of transferring a low-lying box placed in front of the participant to a shelf of the same height at the participant’s left. It was hypothesized that tilting the box could reduce trunk and knee efforts as well as body asymmetry and improve stability. A tridimensional dynamic rigid body model was used to estimate the triaxial net muscular moment magnitudes at the trunk (L5/SI) and at the knees. An approach to quantify the participants’ dynamic stability was also included. Finally, five angles were computed to characterize body asymmetries. The results showed that tilting the box affected specific trunk efforts, but did not succeed in reducing trunk asymmetric efforts. However, the tilts were executed in a single direction, and it may be possible that combined tilts of the box could help reduce trunk asymmetric efforts. Tilting the box had little effect on knee loadings, and the left tilt strategy reduced participants’ stability. This study showed the importance of considering the position of the box when assessing the risks encountered in asymmetrical handling. 相似文献
994.
Agnieszka Kurczewska Jacek Leśnikowski 《International journal of occupational safety and ergonomics》2013,19(1):77-87
This paper presents the concept of active variable thermoinsulation clothing for users working in low temperatures. Those garments contain heating inserts regulated by a microprocessor temperature controller. This paper also presents the results of tests carried out on the newly designed garments. 相似文献
995.
David Le Marquand 《Natural resources forum》1989,13(2):127-138
It is evident that river basin development in Africa can do much to provide environmental stability to wildly erratic hydrologic and climatic cycles, to produce more food and to contribute to economic growth. The experience to date of river basin development in Africa has not proven as positive as in many developing countries. There are too many examples of ill-conceived and ill-suited schemes that contribute to further environmental degradation, social dislocation and hardship, and weaken already stressed national economies. The experience in Africa suggests that the real challenge for Africans to achieve environmentally self-sustaining water resources development lies in establishing the appropriate social and environmental context for physical development to take place. Attention needs to focus on regional development, multi-objective planning, community participation, environmental resiliency, the institutional arrangements for regional development, and the political and economic conditions within the basin states. 相似文献
996.
997.
998.
The recognition of larvae by worker honeybees 总被引:2,自引:0,他引:2
999.
Over the 20th century, reduced land cultivation has caused an extension of fallow land in several European countries, which
has led to a decrease in biodiversity. Knowledge of dynamic vegetation processes and of the impact of human activities on
biodiversity provides the basis for land management recommendations, as well as for wildlife management programs. We analysed
land-use changes on a small protected island (Ushant, Bretagne, France) using historical documentation (1844) and aerial photographs
taken in 1952 and 1992. Over this period, especially during the last 40 yr, Ushant underwent a complete transformation from
rural landscape to extensive shrubland. No cultivated area remains, grazed areas were moved from the coastal fringe to the
core of the island, while over 40% of the island is fallow land. The relationship between current sheep grazing and vegetation
suggests that grazed meadows used to be close to inhabited areas, i.e. 150 m outside the villages. These results allowed us
to analyse landcover potential related to changes in the intensity of sheep grazing. The scenarios highlighted by our method
provide an objective framework for further assessment of fallow land management. 相似文献
1000.
Specimens of Loripes lucinalis (Lucinidae) living in reducing sediments were collected near a sewage outfall at low tide on the Moulin Blanc beach, Brest, France, from January to March 1987. Electron microscope studies revealed numerous Gram-negative-type bacteria in the gill cells. Ribulosebiphosphate carboxylase, a diagnostic enzyme of the Calvin-Benson cycle of CO2-fixation was measured only in the gill extracts. Various tissues of L. lucinalis were examined for activity of APS reductase, (EC 1.8.99.2), ATP sulphurylase (EC 2.7.7.4) and rhodanese (EC 2.8.1.1), enzymes involved in sulphide oxidation. APS reductase was only found in symbiont-containing tissues, i.e., gills. These enzymatic studies characterise the symbionts as chemoautotrophic sulphide-oxidizing bacteria. Histoautoradiography demonstrated that part of the carbon dioxide fixed by symbiotic bacteria in the gills is translocated to symbiont-free tissues of the bivalve. The ultrastructure of the gill is detailed and a nomenclature based on established and new terminology is proposed to describe the various cellular types comprising the gill filament. 相似文献