全文获取类型
收费全文 | 2548篇 |
免费 | 74篇 |
国内免费 | 24篇 |
专业分类
安全科学 | 181篇 |
废物处理 | 151篇 |
环保管理 | 541篇 |
综合类 | 298篇 |
基础理论 | 586篇 |
环境理论 | 3篇 |
污染及防治 | 580篇 |
评价与监测 | 179篇 |
社会与环境 | 92篇 |
灾害及防治 | 35篇 |
出版年
2023年 | 11篇 |
2022年 | 19篇 |
2021年 | 27篇 |
2020年 | 26篇 |
2019年 | 26篇 |
2018年 | 61篇 |
2017年 | 58篇 |
2016年 | 76篇 |
2015年 | 72篇 |
2014年 | 70篇 |
2013年 | 231篇 |
2012年 | 108篇 |
2011年 | 148篇 |
2010年 | 114篇 |
2009年 | 131篇 |
2008年 | 127篇 |
2007年 | 143篇 |
2006年 | 133篇 |
2005年 | 97篇 |
2004年 | 85篇 |
2003年 | 107篇 |
2002年 | 71篇 |
2001年 | 54篇 |
2000年 | 53篇 |
1999年 | 41篇 |
1998年 | 39篇 |
1997年 | 34篇 |
1996年 | 33篇 |
1995年 | 26篇 |
1994年 | 34篇 |
1993年 | 31篇 |
1992年 | 21篇 |
1991年 | 24篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 16篇 |
1987年 | 19篇 |
1986年 | 13篇 |
1985年 | 19篇 |
1984年 | 12篇 |
1983年 | 18篇 |
1982年 | 19篇 |
1981年 | 24篇 |
1980年 | 13篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1971年 | 6篇 |
1957年 | 5篇 |
1955年 | 5篇 |
排序方式: 共有2646条查询结果,搜索用时 187 毫秒
281.
Terence A. Palmer Paul A. Montagna Richard D. Kalke 《Environmental monitoring and assessment》2013,185(7):5917-5935
Packery Channel is part of a complex of storm washover channels which, before 1912, have opened intermittently, linking the Laguna Madre and Corpus Christi Bay, Texas with the Gulf of Mexico. On 21 July 2005, with the assistance of Hurricane Emily, Packery Channel was prematurely opened to the Gulf of Mexico, months before construction of a dredged channel was scheduled to be completed. A before-versus-after, control-versus-impact (BACI) design was used to assess the effects of reopening Packery Channel on water quality and estuarine macrofauna in Mollie Beattie Coastal Habitat Community (MBCHC), Corpus Christi Bay. Two deep (approximately 1 m below m.s.l.) and two shallow (approximately 0.2 m below m.s.l.) stations were sampled monthly for physical and biological characteristics at both control and impact sites between November 2003 and March 2009. The opening of Packery Channel created a unique situation where salinities decreased after the channel opening by ameliorating hypersalinity in Laguna Madre rather than increasing salinities as would occur in most estuaries worldwide. Salinity also fluctuated in a diurnal pattern after the opening of Packery Channel. Apart from salinity, Packery Channel has caused little hydrographic change in MBCHC since opening in July 2005. There was little effect on the macrofaunal community composition. There was a greater difference in community composition between deep and shallow stations than between either before and after or control and impact sites. There have been no significant changes in abundance, biomass, or N1 diversity caused by the opening of Packery Channel. 相似文献
282.
Paul E. Spector 《组织行为杂志》2012,33(2):151-152
This paper introduces a Journal of Organizational Behavior point/counterpoint exchange (this issue) that focuses on the appropriate level of aggregation primarily in the assessment of personality in general and core self‐evaluations (CSE) in particular. Gilad Chen reviews arguments for and against the higher‐order construct of CSE, offering a number of recommendations for strengthening it. Timothy Judge and John Kammeyer‐Mueller offer a defense of CSE, and then extend the discussion to the measurement of other constructs beyond the personality domain. Together these two papers provide important insights about the appropriate level of aggregation of individual measures, and situations in which higher‐order versus lower‐order measures might be preferred. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
283.
Sylvain Plouffe Paul Lanoie Corinne Berneman Marie-France Vernier 《Journal of Cleaner Production》2011,19(6-7):573-579
This paper reports results of an empirical study conducted to assess the profitability of ecodesigned products. Indeed, the advantages related to ecodesign are numerous according to the literature on the subject. Not only is it considered to be an efficient environmental approach, it is also said to carry a number of economic advantages for the firms adopting it. Among these advantages, the potential reduction of costs and an increase in revenues are the most important drivers. Nevertheless, the economic benefits have not been demonstrated, only indicated as a potential outcome. The main purpose of the study was to assess the economic impact of ecodesigned products and to compare the results of French companies with those of Quebec.Semi-structured interviews were conducted with 30 firms on their related ecodesign experience (15 in France, 15 in Quebec), the subsequent results were reached pertaining to the economic benefits tied to such an approach. In 24 cases, firms increased their profits with ecodesigned products. In three cases, profits are equivalent and in the three remaining cases, it is not obvious that the increased revenues compensate for the reduction of margin. French companies were found to be more profitable than the Quebec cases; this can be explained by the fact that French companies have a more systemic approach and therefore manage to make cost savings at several stages in the product life-cycle. We can conclude that the most important aspects to consider when getting involved in an ecodesign project is to focus on increased functionality of the product and to seek environmental and economic improvement on as many life-cycle stages as possible. 相似文献
284.
Paul L. Flint 《Marine Biology》2013,160(1):59-65
Broad-scale multi-species declines in populations of North American sea ducks for unknown reasons is cause for management concern. Oceanic regime shifts have been associated with rapid changes in ecosystem structure of the North Pacific and Bering Sea. However, relatively little is known about potential effects of these changes in oceanic conditions on marine bird populations at broad scales. I examined changes in North American breeding populations of sea ducks from 1957 to 2011 in relation to potential oceanic regime shifts in the North Pacific in 1977, 1989, and 1998. There was strong support for population-level effects of regime shifts in 1977 and 1989, but little support for an effect of the 1998 shift. The continental-level effects of these regime shifts differed across species groups and time. Based on patterns of sea duck population dynamics associated with regime shifts, it is unclear if the mechanism of change relates to survival or reproduction. Results of this analysis support the hypothesis that population size and trends of North American sea ducks are strongly influenced by oceanic conditions. The perceived population declines appear to have halted >20 years ago, and populations have been relatively stable or increasing since that time. Given these results, we should reasonably expect dramatic changes in sea duck population status and trends with future oceanic regime shifts. 相似文献
285.
Environmental and Ecological Statistics - 相似文献
286.
Effects of management and climate on elk brucellosis in the Greater Yellowstone Ecosystem. 总被引:1,自引:0,他引:1
Paul C Cross William H Edwards Brandon M Scurlock Eric J Maichak Jared D Rogerson 《Ecological applications》2007,17(4):957-964
Every winter, government agencies feed approximately 6000 metric tons (6 x 10(6) kg) of hay to elk in the southern Greater Yellowstone Ecosystem (GYE) to limit transmission of Brucella abortus, the causative agent of brucellosis, from elk to cattle. Supplemental feeding, however, is likely to increase the transmission of brucellosis in elk, and may be affected by climatic factors, such as snowpack. We assessed these possibilities using snowpack and feeding data from 1952 to 2006 and disease testing data from 1993 to 2006. Brucellosis seroprevalence was strongly correlated with the timing of the feeding season. Longer feeding seasons were associated with higher seroprevalence, but elk population size and density had only minor effects. In other words, the duration of host aggregation and whether it coincided with peak transmission periods was more important than just the host population size. Accurate modeling of disease transmission depends upon incorporating information on how host contact rates fluctuate over time relative to peak transmission periods. We also found that supplemental feeding seasons lasted longer during years with deeper snowpack. Therefore, milder winters and/or management strategies that reduce the length of the feeding season may reduce the seroprevalence of brucellosis in the elk populations of the southern GYE. 相似文献
287.
288.
289.
290.
The reduction of SO2, HCl, and NO(x) concentrations using calcium magnesium acetate (CMA) as a novel sorbent in a simulated municipal waste incinerator flue gas was investigated. The reduction of individual SO2, HCl, and NO(x) concentrations was tested at 850 degrees C and it was found that CMA could reduce the SO2 concentration by 74%, HCl concentration by 64%, or NO(x) concentration by 94%. It was observed that individual SO2 or HCl capture increased with increasing initial oxygen concentration in the reacting gas or increasing sorbent input. NO(x) reduction decreased with increasing initial oxygen concentration in the reacting gas. The simultaneous reduction of SO2, HCl, and NO(x) concentrations by CMA was also investigated. It was found that CMA could simultaneously capture 60% SO2 and 61% HCl and reduce NO(x) concentrations by 26%, when the initial oxygen concentration in the reacting gas was 4%. During the simultaneous reduction of SO2, HCl, and NO(x), it was noted that as the initial oxygen concentration in the reacting gas increased, the efficiency of SO2 capture increased too, but the efficiency of HCl capture and the efficiency of NO(x) destruction decreased. 相似文献