全文获取类型
收费全文 | 937篇 |
免费 | 10篇 |
国内免费 | 15篇 |
专业分类
安全科学 | 59篇 |
废物处理 | 20篇 |
环保管理 | 131篇 |
综合类 | 140篇 |
基础理论 | 260篇 |
环境理论 | 1篇 |
污染及防治 | 227篇 |
评价与监测 | 82篇 |
社会与环境 | 34篇 |
灾害及防治 | 8篇 |
出版年
2023年 | 7篇 |
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 17篇 |
2017年 | 14篇 |
2016年 | 20篇 |
2015年 | 28篇 |
2014年 | 15篇 |
2013年 | 101篇 |
2012年 | 39篇 |
2011年 | 62篇 |
2010年 | 46篇 |
2009年 | 50篇 |
2008年 | 58篇 |
2007年 | 48篇 |
2006年 | 36篇 |
2005年 | 31篇 |
2004年 | 29篇 |
2003年 | 28篇 |
2002年 | 35篇 |
2001年 | 17篇 |
2000年 | 19篇 |
1999年 | 6篇 |
1998年 | 16篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 9篇 |
1994年 | 13篇 |
1993年 | 9篇 |
1992年 | 11篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1971年 | 4篇 |
1969年 | 4篇 |
1960年 | 4篇 |
1956年 | 3篇 |
排序方式: 共有962条查询结果,搜索用时 46 毫秒
881.
Elaine J. Brough Bruce Frank Frank Page Stewart Lindsay 《Agriculture, ecosystems & environment》1996,60(2-3)
An interdisciplinary team introduced Integrated Mite Control (IMC) to the Queensland apple industry in Australia from 1989 to 1992. Project funding supported the employment of a consultant to monitor mite levels and provide management advice to growers who paid for the service. Interviews at the beginning and end of the project showed widespread adoption of IMC over this period. Overall use of chemicals was not reduced, but the use pattern changed towards wider use of chemicals that are less toxic to predatory mites. The future of IMC in the Queensland apple industry is in doubt because the seasonal nature of apple production does not allow the paid consultancy service to be self-sustaining. Indications are that the integrated approach to pest management may not be generally accepted as a strategic management process while the availability of effective chemicals allows the continuation of a spray routine for mite control. The lack of availability of effective and proven methods of pest control was seen by growers as the major constraint to adoption of IMC. 相似文献
882.
I used estimates of carrying capacity, survival, fecundity, and edge effects to simulate the responses of a forest-interior bird population to selection cutting clearcutting, and no timber harvest. I also modeled population sensitivity to changes in fecundity, survival, K , and edge relationships. Because model parameters are based on scant data, results should he regarded as hypotheses to be further investigated or measures of the relative impact or sensitivity (given model assumptions). Simulated population size was greater with no timber harvest than with clearcutting and greater with clearcutting than with group selection when edge effects were included in the model. Without edge effects, population levels were only slightly lower under group selection than under no timber harvest, and greater than clearcutting. Edge effects had only a small impact on population levels under clearcutting. Clearcut size did not have much effect on population levels, but longer and shorter rotation ages resulted in higher and lower population levels, respectively. The model was very sensitive to declines in mean fecundity and survival, suggesting that factors affecting mean demographic rates could be more important than local edge effects. Some methods of timber harvest may be compatible with the conservation of forest-interior birds, but better demographic data and information on habitat suitability of selectively cut forests and young even-aged stands is needed to adequately evaluate management options. 相似文献
883.
Thiagarajah Ramilan Frank Scrimgeour Dan Marsh 《Environmental Modeling and Assessment》2012,17(4):399-410
Microsimulation can be used to extend the use of scarce survey resources by creating simulated populations whose characteristics are close to those of the real population. The technique involves merging detailed survey observations with variables from more extensive data sets in order to create a simulated population. We illustrate how microsimulated data enable analysis of the economic and environmental impact of different policies on a catchment for which detailed farm level data was unavailable. Use of microsimulation for agri-environmental policy analysis is applicable to diverse problems from simulation of nitrogen trading to modelling of agent response to policy shocks. Scale flexibility is easily implemented since data can be aggregated or disaggregated to the preferred scale. Simulated catchment data allows better understanding of the effects of policies on different types of farm and should be extremely valuable to organisations that want to minimise the economic impact of environmental policies. 相似文献
884.
885.
ABSTRACT. A rationale is set forth for requiring and/or encouraging the consolidation or regionalization of all systems beneath certain population size levels based on the small water systems’ capability to produce an adequate supply of safe drinking water at a reasonable cost to customers. Estimates for basic costs of water service including personnel, other operation and maintenance and capital are made and a range of water rates is suggested based on reasonableness and acceptability to customers. Guidelines are then drawn for a moderate rate of $10.00 per month and an upper limit rate of $15.00 per month to show the sizes at which public water systems might be expected to achieve fiscal viability. Finally, recommendations are made to State and Federal governmental agencies concerning possible legislation, plans and programs to achieve better public water service through the regionalization or consolidation of small public water systems. 相似文献
886.
Terry W. Rothermel Milton S. Sachs Frank O'Shaughnessy 《Journal of the American Water Resources Association》1971,7(4):867-877
ABSTRACT The Office of Saline Water, which has federal responsibility for developing low-cost, saline sources of fresh water, has recognized the need for an improved method of forecasting the future potential of desalting in this country. The magnitude of the role of desalting will influence the plans of federal, state, and local water resource agencies and the research and development programs of manufacturers. A dynamic simulation model has been developed by Arthur D. Little, Inc. under contract by OSW to translate relevant factors of water supply and demand into a forecast of desalting potential. The model projects the needs for desalting in 20 hydrologic regions of the U.S. Model performance has thus far been demonstrated by the development of a forecast and a battery of related sensitivity tests. Current results indicate the following potential desalting capacities: 225 MGD in 1980; 2,250 MGD in 2000; and 7,000 MGD in 2020. Significant improvements in desalting economics promise to increase these potentials by a factor of four or five by 2000-2020. Model inputs and results are continuing to be refined. When completed, OSW will have a dynamic tool with which to guide its R&D program. 相似文献
887.
Uekoetter F 《Environmental monitoring and assessment》2005,106(1-3):11-26
The Ringelmann smoke chart was used in the United States to assess smoke emissions in the early twentieth century. In fact, it may have been the most important method for measuring air pollution between the late 1800s and the environmental era. However, the popularity of the Ringelmann chart stood in stark contrast to its lack of precision, which smoke abatement experts recognized and discussed among themselves. However, the critique of the Ringelmann scale rarely left the circle of experts and never jeopardized its use. This article discusses the reasons for this striking phenomenon, pointing out that the Ringelmann chart had strong practical and symbolic advantages: it allowed smoke abatement to be conducted in a public and transparent way. With that, the history of the Ringelmann smoke chart is an instructive model for the social construction of measuring techniques. 相似文献
888.
Growth and population structure in the infaunal bivalve Yoldia eightsi in relation to iceberg activity at Signy Island,Antarctica 总被引:3,自引:0,他引:3
Growth rates in the infaunal nuculanid bivalve mollusc Yoldia eightsi (Couthouy) were assessed for field populations in Factory Cove, Signy Island, Antarctica, between. February and April 1992. Daily increments in length (maximum shell dimension) ranged from 2.3 m d-1 for a 30 mm individual to 5.1 m d-1 for a 10 mm specimen. These growth rates were converted to annual increments, based on a growing season for the Signy population of around 5 mo, and ages for the largest individuals in the population (35 mm in length), were calculated to be 65 yr. Specimens of 43 mm in length have been found near this site and, if their growth rates are similar to this population, their ages would be in the order of 120 yr. Size distributions from two sites in the same Y. eightsi bed 300 m apart showed significant differences. At the more exposed site the distribution was dominated by small juveniles, with 86% of the population 10 mm in length, while 13% were >20 mm in length. At the less exposed site the values were 27% <10 mm and 56% >20 mm. Icebergs have often been seen grounded on the Y. eightsi bed in this study, especially on the exposed outer portion. This factor, in association with inhibition of larval settlement by high densities of large individuals, is proposed as an explanation of the observed population distributions and the absence of very large specimens in the Factory Cove population. 相似文献
889.
890.
Frank J. Landy 《组织行为杂志》2005,26(4):411-424
In the past decade, the concept of emotional intelligence (EI) has emerged as a potential new construct for explaining behavioral variance not accounted for by traditional measures of general academic intelligence or personality. EI researchers credit E. L. Thorndike as the first to propose such a construct when he suggested that social intelligence is independent of abstract or academic intelligence. The current paper traces the historical roots of social intelligence and the current scientific status of emotional intelligence. It appears that emotional intelligence, as a concept related to occupational success, exists outside the typical scientific domain. Much of the data necessary for demonstrating the unique association between EI and work‐related behavior appears to reside in proprietary databases, preventing rigorous tests of the measurement devices or of their unique predictive value. For those reasons, any claims for the value of EI in the work setting cannot be made under the scientific mantle. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献