全文获取类型
收费全文 | 19286篇 |
免费 | 1336篇 |
国内免费 | 2338篇 |
专业分类
安全科学 | 3264篇 |
废物处理 | 214篇 |
环保管理 | 2912篇 |
综合类 | 9627篇 |
基础理论 | 2003篇 |
环境理论 | 12篇 |
污染及防治 | 963篇 |
评价与监测 | 1037篇 |
社会与环境 | 1731篇 |
灾害及防治 | 1197篇 |
出版年
2024年 | 48篇 |
2023年 | 198篇 |
2022年 | 382篇 |
2021年 | 560篇 |
2020年 | 542篇 |
2019年 | 452篇 |
2018年 | 400篇 |
2017年 | 590篇 |
2016年 | 716篇 |
2015年 | 745篇 |
2014年 | 801篇 |
2013年 | 1029篇 |
2012年 | 1346篇 |
2011年 | 1516篇 |
2010年 | 1103篇 |
2009年 | 1056篇 |
2008年 | 847篇 |
2007年 | 1283篇 |
2006年 | 1319篇 |
2005年 | 1049篇 |
2004年 | 874篇 |
2003年 | 952篇 |
2002年 | 754篇 |
2001年 | 638篇 |
2000年 | 584篇 |
1999年 | 584篇 |
1998年 | 445篇 |
1997年 | 346篇 |
1996年 | 304篇 |
1995年 | 271篇 |
1994年 | 260篇 |
1993年 | 229篇 |
1992年 | 179篇 |
1991年 | 135篇 |
1990年 | 83篇 |
1989年 | 53篇 |
1988年 | 47篇 |
1987年 | 24篇 |
1986年 | 22篇 |
1985年 | 32篇 |
1984年 | 16篇 |
1983年 | 20篇 |
1982年 | 14篇 |
1981年 | 16篇 |
1980年 | 12篇 |
1979年 | 14篇 |
1977年 | 14篇 |
1974年 | 8篇 |
1973年 | 14篇 |
1972年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
101.
Although the process of documenting compliance with NEPA (the National Environmental Policy Act) requires no drastic revisions, it can be managed more rigorously. Suggestions for revision can be grouped under five major steps: 1) getting a complete proposal from the applicant; 2) getting the decision-making process onto the right decision-making path; 3) modifying the applicant's proposal 4) going down a shorter path through the EA/FONSI (environmental assessment and finding of no significant impact) or through categorical exclusion review; and 5) going down the longer path through the EIS. Step 2 is perhaps the most critical, because there a decision must be made whether to write an EA/FONSI or an EIS, on the basis of whether the proposal would “significantly affect … the … environment.” In the past, this decision has not always been made promptly or rigorously. Accordingly, we suggest that the agency responsible for NEPA compliance should develop a system (a “black box”), consisting of a core group of specialists working with an interdisciplinary team, using sophisticated techniques for modeling impacts and directing both their research and their writing according to the concept of significance. By determining more efficiently and reliably whether the impacts of a proposal would be significant, such an approach would improve management of the total process. 相似文献
102.
硫酸盐化速率反映大气中二氧化硫及硫的化合物的污染状况,文章通过对银川市1999~2003年硫酸盐化速率的346个监测数据的统计分析,研究了煤烟型城市环境空气中二氧化硫的变化规律及污染状况。 相似文献
103.
对城市生活垃圾的分类回收、处理进行了探讨,对完善城市基础设施建设,改善投资环境将起到重要作用。 相似文献
104.
Economic development and environmental protection: an ecological economics perspective 总被引:5,自引:0,他引:5
Rees WE 《Environmental monitoring and assessment》2003,86(1-2):29-45
This paper argues on both theoretical and empirical grounds that, beyond a certain point, there is an unavoidable conflictbetween economic development (generally taken to mean 'materialeconomic growth') and environmental protection. Think for a moment of natural forests, grasslands, marine estuaries, salt marshes, and coral reefs; and of arable soils, aquifers, mineraldeposits, petroleum, and coal. These are all forms of 'natural capital' that represent highly-ordered self-producing ecosystemsor rich accumulations of energy/matter with high use potential (low entropy). Now contemplate despoiled landscapes, eroding farmlands, depleted fisheries, anthropogenic greenhouse gases,acid rain, poisonous mine tailings and toxic synthetic compounds.These all represent disordered systems or degraded forms of energy and matter with little use potential (high entropy). The main thing connecting these two states is human economic activity. Ecological economics interprets the environment-economyrelationship in terms of the second law of thermodynamics. The second law sees economic activity as a dissipative process. Fromthis perspective, the production of economic goods andservices invariably requires the consumption of available energy and matter. To grow and develop, the economynecessarily 'feeds' on sources of high-quality energy/matter first produced by nature. This tends to disorder and homogenizethe ecosphere, The ascendance of humankind has consistently been accompanied by an accelerating rate of ecological degradation, particularly biodiversity loss, the simplificationof natural systems and pollution. In short, contemporary political rhetoric to the contrary, the prevailing growth-oriented global development paradigm is fundamentally incompatible with long-term ecological and social sustainability. Unsustainability is not a technical nor economic problem as usually conceived, but rather a state of systemic incompatibilitybetween a economy that is a fully-contained, growing, dependent sub-system of a non-growing ecosphere. Potential solutions fly inthe face of contemporary development trends and cultural values. 相似文献
105.
Llansó RJ Dauer DM Vølstad JH Scott LC 《Environmental monitoring and assessment》2003,81(1-3):163-174
The Chesapeake Bay benthic index of biotic integrity (B-IBI) was developed to assess benthic community health and environmental quality in Chesapeake Bay. The B-IBI provides Chesapeake Bay monitoring programs with a uniform tool with which to characterize bay-wide benthic community condition and assess the health of the Bay. A probability-based design permits unbiased annual estimates of areal degradation within the Chesapeake Bay and its tributaries with quantifiable precision. However, of greatest interest to managers is the identification of problem areas most in need of restoration. Here we apply the B-IBI to benthic data collected in the Bay since 1994 to assess benthic community degradation by Chesapeake Bay Program segment and water depth. We used a new B-IBI classification system that improves the reliability of the estimates of degradation. Estimates were produced for 67 Chesapeake Bay Program segments. Greatest degradation was found in areas that are known to experience hypoxia or show toxic contamination, such as the mesohaline portion of the Potomac River, the Patapsco River, and the Maryland mainstem. Logistic regression models revealed increased probability of degraded benthos with depth for the lower Potomac River, Patapsco River, Nanticoke River, lower York River, and the Maryland mainstem. Our assessment of degradation by segment and water depth provided greater resolution of relative condition than previously available, and helped define the extent of degradation in Chesapeake Bay. 相似文献
106.
107.
108.
Risk-Based Prioritization of Air Pollution Monitoring Using Fuzzy Synthetic Evaluation Technique 总被引:1,自引:0,他引:1
Air pollution monitoring programs aim to monitor pollutants and their probable adverse effects at various locations over concerned area. Either sensitivity of receptors/location or concentration of pollutants is used for prioritizing the monitoring locations. The exposure-based approach prioritizes the monitoring locations based on population density and/or location sensitivity. The hazard-based approach prioritizes the monitoring locations using intensity (concentrations) of air pollutants at various locations. Exposure and hazard-based approaches focus on frequency (probability of occurrence) and potential hazard (consequence of damage), respectively. Adverse effects should be measured only if receptors are exposed to these air pollutants. The existing methods of monitoring location prioritization do not consider both factors (hazard and exposure) at a time. Towards this, a risk-based approach has been proposed which combines both factors: exposure frequency (probability of occurrence/exposure) and potential hazard (consequence).This paper discusses the use of fuzzy synthetic evaluation technique in risk computation and prioritization of air pollution monitoring locations. To demonstrate the application, common air pollutants like CO, NOx, PM10 and SOx are used as hazard parameters. Fuzzy evaluation matrices for hazard parameters are established for different locations in the area. Similarly, fuzzy evaluation matrices for exposure parameters: population density, location and population sensitivity are also developed. Subsequently, fuzzy risk is determined at these locations using fuzzy compositional rules. Finally, these locations are prioritized based on defuzzified risk (crisp value of risk, defined as risk score) and the five most important monitoring locations are identified (out of 35 potential locations). These locations differ from the existing monitoring locations. 相似文献
109.
Selecting Socio-Economic Metrics for Watershed Management 总被引:1,自引:0,他引:1
The selection of social and economic metrics to document baseline conditions and analyze the dynamic relationships between
ecosystems and human communities are important decisions for scientists, managers, and watershed citizens. A large variety
of social and economic data is available but these have limited use without theoretical frameworks. In this paper, several
frameworks for reviewing social-ecosystem relations are offered, namely social sanctions, sense of place, civic structure,
and cultural differences. Underlying all of these frameworks are attitudes, beliefs, values, and norms that affect which questions
are asked and which indicators are chosen. Much work and significant challenges remain in developing a standard set of spatially
based socio-economic metrics for watershed management. 相似文献
110.
汉江水质评价的化学计量学研究 总被引:4,自引:1,他引:4
运用因子分析法对汉江各主要水质断面进行水质因子分析及综合评价,通过各主因子的方差贡献及因子得分得出各水质因子的赋权值,从而对所取断面进行水质污染程度的综合评价、分析与排序。同时运用聚类分析法对汉江17个断面的水质污染相似性进行分析,给出分类处理结果。 相似文献