全文获取类型
收费全文 | 1214篇 |
免费 | 68篇 |
国内免费 | 49篇 |
专业分类
安全科学 | 361篇 |
废物处理 | 9篇 |
环保管理 | 154篇 |
综合类 | 458篇 |
基础理论 | 78篇 |
环境理论 | 2篇 |
污染及防治 | 31篇 |
评价与监测 | 33篇 |
社会与环境 | 115篇 |
灾害及防治 | 90篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 37篇 |
2021年 | 52篇 |
2020年 | 44篇 |
2019年 | 37篇 |
2018年 | 28篇 |
2017年 | 27篇 |
2016年 | 41篇 |
2015年 | 41篇 |
2014年 | 45篇 |
2013年 | 62篇 |
2012年 | 73篇 |
2011年 | 89篇 |
2010年 | 81篇 |
2009年 | 74篇 |
2008年 | 78篇 |
2007年 | 86篇 |
2006年 | 102篇 |
2005年 | 72篇 |
2004年 | 60篇 |
2003年 | 46篇 |
2002年 | 46篇 |
2001年 | 25篇 |
2000年 | 25篇 |
1999年 | 13篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1986年 | 1篇 |
1984年 | 2篇 |
排序方式: 共有1331条查询结果,搜索用时 203 毫秒
991.
粮食安全:气候变化与粮食产地转移 总被引:2,自引:0,他引:2
基于1985-2008年中国雀际面板数据,实证检验了气候变化对粮食种植规模与单位产量的作用机制,进而分析了产地转移对国家粮食总供给的影响.结论表明:①中国的稻谷、小麦、玉米产业正分别向黑龙江、河南、内蒙古等气候资源匮乏地区转移或集聚;②粮食产地转移的主导因素在于粮食作物与经济作物、种植业与畜牧业、农业与非农的成本收益比较,而气候变化因素仅处于附属地位;③基于规模效应、牧入效应以及回弹效应的作用机制,东北三省、河南、内蒙古等地区的增长潜质往往优于其他地区;④落后地区应对气候变化的生产与政策成本,往往要低于发达地区保留粮食生产的机会成本,粮食生产向欠发达地区转移应具有可持久性.粮食产地转移过程中,并未呈现粮食供给安全的“个体理性”与“集体理性”的冲突.中国应该在气象预报、水利设施、抗灾能力、中低产田改造等方面加大投入,摒弃区内平衡的传统观念,在全国范围内优化资源配置,并辅以国家粮食储备战略应对特大灾害的供给风险. 相似文献
992.
着眼于如何科学促进工业结构升级,发展技术含量和附加值双高、社会效益与经济效益双优的"两型"工业部门,首次将产业安全和隐含碳纳入考量,分别从经济效益、社会效益、生态效益、技术密集度、产业安全、区域优势6个方面选取了13项指标.在对所选指标进行相应说明后,应用主成分分析法建立了湖北省工业结构调整评价体系.该评价体系对湖北省的24个工业部门进行了综合评分及排序,分析结果显示未来几年湖北省应该大力发展三类产业:一是经济效益好、社会关联度大,但存在一定污染问题的产业;二是增长速度快、技术含量与外向度较高的产业;三是就业能力强,区域优势明显的产业.同时,三类产业的发展策略各有侧重.文章最后依据各项指标对于湖北省几个重点工业部门发展给出了针对性的政策建议. 相似文献
993.
Liu Yanhua Ge Quansheng Fang Xiuqi Zhang Xueqin . Ministry of Science Technology of the People’s Republic of China Beijing China . Chinese National Committee for the International Human Dimensions Programme on Global Enviornmental Change Beijing . Institute of Geographical Sciences Natural Resources Research Chinese Academy of Sciences . School of Geography Beijing Normal University Beijing 《中国人口.资源与环境(英文版)》2011,9(1):3-8
The concept of security has been redefined since the 1990s. As one of the important factors threatening human security, global environmental change has become a new challenge to the national security and social development. The national security problems caused by global environmental change, on one hand, are closely related to the global environmental problems, and, on the other hand, are manifested in the conflicts of international affairs. The global environmental change severely challenges the future de... 相似文献
994.
土地利用总体规划的生态环境影响评价对于保护区域生态环境、减少土地利用总体规划对环境的负面影响具有重要的意义。以格网单元为基础,结合PSR模型和生态安全评价法,通过相关性分析筛选指标,构建评价指标体系。通过GIS空间分析,定量评价县级土地利用总体规划环境影响。以张家界市永定区为例,综合评价了规划实施前后区域生态环境的状况。评价结果表明:新一轮的土地利用总体规划后,全区生态环境状况有改善的地区占全区总面积的7819%,说明新的规划对全区大部分地区的生态环境有积极影响。其中,水土流失指数处于安全和较安全的区域占全区总面积的6017%,全区水土流失状况略有好转,加强水土保持工程建设仍是用永定区生态环境保护的首要任务之一 相似文献
995.
Towards global phosphorus security: a systems framework for phosphorus recovery and reuse options 总被引:7,自引:0,他引:7
Human intervention in the global phosphorus cycle has mobilised nearly half a billion tonnes of the element from phosphate rock into the hydrosphere over the past half century. The resultant water pollution concerns have been the main driver for sustainable phosphorus use (including phosphorus recovery). However the emerging global challenge of phosphorus scarcity with serious implications for future food security, means phosphorus will also need to be recovered for productive reuse as a fertilizer in food production to replace increasingly scarce and more expensive phosphate rock. Through an integrated and systems framework, this paper examines the full spectrum of sustainable phosphorus recovery and reuse options (from small-scale low-cost to large-scale high-tech), facilitates integrated decision-making and identifies future opportunities and challenges for achieving global phosphorus security. Case studies are provided rather than focusing on a specific technology or process. There is no single solution to achieving a phosphorus-secure future: in addition to increasing phosphorus use efficiency, phosphorus will need to be recovered and reused from all current waste streams throughout the food production and consumption system (from human and animal excreta to food and crop wastes). There is a need for new sustainable policies, partnerships and strategic frameworks to develop renewable phosphorus fertilizer systems for farmers. Further research is also required to determine the most sustainable means in a given context for recovering phosphorus from waste streams and converting the final products into effective fertilizers, accounting for life cycle costs, resource and energy consumption, availability, farmer accessibility and pollution. 相似文献
996.
Assessing the ecological security of the Tibetan plateau: methodology and a case study for Lhaze County 总被引:22,自引:0,他引:22
Zhao YZ Zou XY Cheng H Jia HK Wu YQ Wang GY Zhang CL Gao SY 《Journal of environmental management》2006,80(2):120-131
A system for assessing the ecological security of Lhaze County in China's Tibetan Autonomous Region was developed using a pressure-state-response model and the analytic hierarchy process. We then used this model to comprehensively evaluate the status of ecological security in Lhaze County. Our results showed that the ecological environment in Lhaze County has deteriorated from an 'early stages of damage status' in the 1980s to 'moderately damaged status' today. This deterioration has become a major barrier to local economic development and social advancement. Natural and social aspects related to the population explosion, resource exploitation, and climate change that led to this ecological deterioration are discussed. Furthermore, we have suggested proposals for improving the ecological environment that include controlling population growth and enhancing the system of laws that protect the environment, upgrading 3 882.6 ha of low-yield farmland, planting 2 425.8, 548.8, and 1 207.4 ha of shelter belts for farmland protection, soil and water conservation, and fuelwood, respectively, and seeding 2 358.1 ha of artificial grassland. In the meantime, we propose strengthening the controls that limit soil and water loss, and optimizing industrial sectors that aspire to achieve high-efficiency, ecologically responsible agriculture. 相似文献
997.
中国能源安全及其资源开发与利用的策略研究 总被引:8,自引:0,他引:8
通过采用“霍夫曼系数”的分析方法,提出能源危机是国家在工业化过程中的必经阶段,并从资源经济理论角度认识我国经济增长对资源消耗的关系,剖析国际能源危机背景与经济格局的成因。中国目前和今后主要受制于国内资源不足,要应对能源危机,只有实现多元化的策略,才能保障能源的供应,实现我国经济社会和谐、稳定、可持续发展。因此,能源资源开发与利用策略的研究具有极其重要的现实意义。 相似文献
998.
大气环境安全评估体系研究 总被引:3,自引:0,他引:3
环境安全是国家安全的重要组成部分,已引起世界各国的广泛关注.从我国大气环境安全形势出发,应用压力-状态-响应(PSR)模型,搭建了4层3度的指标体系.从大气环境安全的压力、状态、响应3个方面确定相应的指数,并选取评估指标,确立评估标准.通过层次分析法(AHP)确定指标权重,用权重求和法计算指数分值.应用建立的大气环境安全评估体系,对省级大气环境安全进行了评估.结果表明:我国区域大气环境安全呈片状分布较为明显,大部分省份的大气环境安全均处于预警和中警状态,大气环境安全需要进一步加强.从区域差异分析可知,东部大气环境安全好于中西部地区.对关键影响因子的分析表明,能源消耗是影响北方大气环境安全的关键因子,南方受酸雨影响严重.总体上我国大气环境安全状况呈好转的趋势. 相似文献
999.
ZHU Cheng-jun CHENG Shu-pei ZHANG Xu-xiang LANG You-zhe SUN Shi-lei GU Ji-dong ZHAO Da-yong PAN Wen-yang YU Hong-xia 《环境科学学报(英文版)》2006,18(3):514-518
The purified terephthalic acid (PTA) petrochemical wastewater molecular toxicity detected by use of Mouse Genome 430A 2.0 GeneChip was conducted in this research. The toxic dose to male mice was 0.03 g/(kg, d) of PTA in the wastewater. The mice liver total RNA was isolated as the temple for synthesis of eDNA and then the cDNA as the temple for synthesis of cRNA. Hybridizing the cRNA with the target genes on the gene chip, there were 232 genes expression levels up-regulated and 74 genes down-regulated discovered obviously. The foremost 40 genes for both the highest and the lowest expression levels involved endogenetic steroid and hormone metabolism, immune system, the leukocyte activity and inflammation, detoxification in liver, reproduction and growth hormone, regulation immune factors of anti-tumor and anti-infection and cancer to the mice sampled. The data suggest the PTA wastewater contained over 5 aromatics and their toxicities integrated were much higher than the pure chemical PTA. And the pure chemical PTA toxicities data cannot be used to evaluate the toxicity of the PTA wastewater instead. 相似文献
1000.