全文获取类型
收费全文 | 637篇 |
免费 | 13篇 |
国内免费 | 11篇 |
专业分类
安全科学 | 63篇 |
废物处理 | 17篇 |
环保管理 | 152篇 |
综合类 | 129篇 |
基础理论 | 151篇 |
污染及防治 | 93篇 |
评价与监测 | 34篇 |
社会与环境 | 18篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 8篇 |
2022年 | 4篇 |
2021年 | 13篇 |
2020年 | 16篇 |
2019年 | 6篇 |
2018年 | 18篇 |
2017年 | 15篇 |
2016年 | 26篇 |
2015年 | 17篇 |
2014年 | 22篇 |
2013年 | 47篇 |
2012年 | 19篇 |
2011年 | 41篇 |
2010年 | 20篇 |
2009年 | 27篇 |
2008年 | 32篇 |
2007年 | 28篇 |
2006年 | 31篇 |
2005年 | 29篇 |
2004年 | 21篇 |
2003年 | 22篇 |
2002年 | 25篇 |
2001年 | 14篇 |
2000年 | 20篇 |
1999年 | 7篇 |
1998年 | 7篇 |
1997年 | 6篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1962年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有661条查询结果,搜索用时 15 毫秒
151.
James J. Lavelle Joel Brockner Mary A. Konovsky Kenneth H. Price Amy B. Henley Aakash Taneja Vishnu Vinekar 《组织行为杂志》2009,30(3):337-357
Research on commitment, procedural fairness, and organizational citizenship behavior (OCB) suggests that employees maintain distinct beliefs about, and direct behaviors towards, multiple targets in the workplace (e.g., the organization as a whole, their supervisor, and fellow workgroup members). The present studies were designed to test for “target similarity effects,” in which the relationships between commitment, procedural fairness, and OCB were expected to be stronger when they referred to the same target than when they referred to different targets. As predicted, we found that: (1) the positive relationship between commitment and OCB, and (2) the mediating effect of commitment on the positive relationship between procedural fairness and OCB, was particularly likely to emerge when the constructs were in reference to the same target. Support for these target similarity effects was found among layoff survivors (Study 1) and student project teams (Study 2). Theoretical and practical implications are discussed, as are limitations of the studies and suggestions for future research. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
152.
Mary W. Downton Rebecca E. Morss Olga V. Wilhelmi Eve Gruntfest Melissa L. Higgins 《Environmental Hazards》2013,12(3):134-146
Flood management policies in the United States rely on scientific information about the frequency and intensity of extreme precipitation and runoff. Yet, the available information is inherently uncertain because of the complexity of meteorological and hydrological processes. In mountainous areas, flood risk can vary greatly even within short distances depending on local climate, topography, soil characteristics, and land use. This paper describes two Colorado cases in which policy makers were presented with conflicting scientific estimates: revision of the Fort Collins floodplain map and modification of the Cherry Creek Dam. The case studies demonstrate that uncertainty can have substantial impacts on regulatory processes, public safety, and costs. The analysis considers the differing perspectives of various participants in the flood management processes, illustrating the interplay between uncertainties attributable to scientific issues and values issues. It suggests that attempts to provide a single “best” estimate do not necessarily meet the decision needs of all stakeholders. Conclusions indicate a need to improve communication about uncertainty when scientific estimates areprovided to decision makers. Furthermore, in highly controversial decisions, it may be necessary to reframe the discussion to consider the values issues raised by scientific uncertainty. 相似文献
153.
Angel CR Powers WJ Applegate TJ Tamim NM Christman MC 《Journal of environmental quality》2005,34(2):563-571
The effect of dietary non-phytin phosphorus (NPP) and phytase (PHY) concentration on total phosphorus (TP) and water-soluble phosphorus (WSP) excretion was determined. Diets tested in broiler experiments were: National Research Council nutrient requirements for non-phytin phosphorus (NRC), NRC + PHY, reduced non-phytin phosphorus (RED), and RED + PHY. Turkey and swine experiment diets included NRC, RED, and RED + PHY. For all experiments, except broiler Experiment 1, excreta were: (i) boiled, antibiotic added, then frozen; (ii) boiled, antibiotic added, incubated (37 degrees C for 72 h), then frozen; and (iii) incubated, boiled, antibiotic added, then frozen. In Experiment 1, excreta were collected and frozen or incubated for 24 or 48 h. In broiler Experiment 1, WSP was not affected by phytase but increased with post-excretion incubation. In a broiler Experiment 2, reducing NPP resulted in reduced excreta TP and WSP (11.3 to 8.3 and 5.3 to 2.7 g kg(-1)). Feeding RED + PHY diets resulted in less TP and WSP (7.6 and 0.6 g kg(-1)) as compared with NRC + PHY (11.2 and 3.9 g kg(-1), Experiment 3). Incubation resulted in increased WSP, irrespective of phytase addition such that WSP as a percent of TP was similar among treatments. Addition of antibiotics before incubation prevented the increase in WSP. Similar results were observed with turkey and swine. Therefore, when phytase is used properly (i.e., with a simultaneous reduction of NPP), WSP or WSP as a percent of TP are not affected. The increase in WSP as a percent of TP post-excretion is a function of excreta microbial activity and not dietary phytase addition. 相似文献
154.
Understanding effects of flow alteration on stream biota is essential to developing ecologically sustainable water supply
strategies. We evaluated effects of altering flows via surface water withdrawals and instream reservoirs on stream fish assemblages,
and compared effects with other hypothesized drivers of species richness and assemblage composition. We sampled fishes during
three years in 28 streams used for municipal water supply in the Piedmont region of Georgia, U.S.A. Study sites had permitted
average withdrawal rates that ranged from < 0.05 to > 13 times the stream’s seven-day, ten-year recurrence low flow (7Q10),
and were located directly downstream either from a water supply reservoir or from a withdrawal taken from an unimpounded stream.
Ordination analysis of catch data showed a shift in assemblage composition at reservoir sites corresponding to dominance by
habitat generalist species. Richness of fluvial specialists averaged about 3 fewer species downstream from reservoirs, and
also declined as permitted withdrawal rate increased above about 0.5 to one 7Q10-equivalent of water. Reservoir presence and
withdrawal rate, along with drainage area, accounted for 70% of the among-site variance in fluvial specialist richness and
were better predictor variables than percent of the catchment in urban land use or average streambed sediment size. Increasing
withdrawal rate also increased the odds that a site’s Index of Biotic Integrity score fell below a regulatory threshold indicating
biological impairment. Estimates of reservoir and withdrawal effects on stream biota could be used in predictive landscape
models to support adaptive water supply planning intended to meet societal needs while conserving biological resources. 相似文献
155.
The safety impact of the 65 mph speed limit: A case study using Alabama accident records 总被引:1,自引:0,他引:1
On August 1, 1987, a change in Alabama laws went into effect raising the speed limit on the rural interstates to 65 mph. Two accident data sets (one year before and one year after the law change) were compared to assess the impact of the 65 mph speed limit on severity and frequency of accidents. Although accident severity appeared to remain the same from before to after time periods, the frequency of accidents on the rural interstates increased significantly, by 18.88%. However, the significant increase on the rural interstates was accompanied by a nonsignificant decrease of 456 accidents in the entire state of Alabama. This confounding result made it difficult to isolate the cause of various significant changes, but the overall evidence is not favorable to the recent increases in driving speeds. 相似文献
156.
The resolution of conflicts arising from differing values and water uses requires technical information and negotiating skills. This article outlines the Instream Flow Incremental Methodology (IFIM), developed by the US Fish and Wildlife Service, and demonstrates that its use to quantify flows necessary to protect desired instream values aids negotiation by illustrating areas of agreement and possible compromises between conflicting water interests. Pursuant to a Section 404 permit application to the US Army Corps of Engineers made by City Utilities of Springfield, Missouri, in 1978, IFIM provided the means by which City Utilities, concerned with a secure water supply for a growing population, and those advocating instream values were satisfied that their requirements were met. In tracing the 15-month process, the authors conclude that the application of IFIM, as well as the cooperative stance adopted by the parties involved, were the key ingredients of the successful permit application. 相似文献
157.
Microbial and environmental effects on avian egg viability: do tropical mechanisms act in a temperate environment? 总被引:1,自引:0,他引:1
The viability of freshly laid avian eggs declines after several days of exposure to ambient temperatures above physiological zero, and declines occur faster in tropical than temperate ecosystems. Microbial infection during preincubation exposure has recently been shown as a second cause of egg viability decline in the tropics, but whether microbial processes influence the viability of wild bird eggs in temperate ecosystems is unknown. We determined the microbial load on eggshells, the incidence of microbial penetration of egg contents, and changes in the viability of wild bird eggs (Sialia mexicana, Tachycineta bicolor, Tachycineta thalassina) experimentally exposed to temperate-zone ambient conditions in situ in a mediterranean climate in northern California. Initial microbial loads on eggshells were generally low, although they were significantly higher on eggs laid in old boxes than in new boxes. Eggshell microbial loads did not increase with exposure to ambient conditions, were not reduced by twice-daily disinfection with alcohol, and were unaffected by parental incubation. The rate of microbial penetration into egg contents was low and unaffected by the duration of exposure. Nevertheless, egg viability declined very gradually and significantly with exposure duration, and the rate of decline differed among species. In contrast to studies performed in the tropics, we found little evidence that temperature or microbial mechanisms of egg viability decline were important at our temperate-zone site; neither temperatures above physiological zero nor alcohol disinfection was significantly related to hatching success. Delaying the onset of incubation until the penultimate or last egg of a clutch at our study site may maintain hatching synchrony without a large trade-off in egg viability. These results provide insight into the environmental mechanisms that may be responsible for large-scale latitudinal patterns in avian clutch size and hatching asynchrony. 相似文献
158.
Ortea PM Allis O Healy BM Lehane M Ní Shuilleabháin A Furey A James KJ 《Chemosphere》2004,55(10):1395-1402
Microcystins, toxic cyclic heptapeptides and nodularin-R, a toxic cyclic pentapeptide, were determined using liquid chromatography (LC) with detection using photo-diode array ultra-violet (PDA-UV) and protein phosphatase (PP) assay. Positive fractions were analysed for toxins using collision-induced dissociation (CID) and tandem MS/MS experiments which were carried out simultaneously using electrospray ion-trap instrumentation. Reversed-phase liquid chromatography (LC) using an acetonitrile/water gradient was used for the LC-MS(2) determination of six microcystins standards and nodularin. The molecular related ion species, [M+H](+)([M+2H](2+) in the case of MC-RR), were used as the precursor ions for MS(2) experiments. Optimum calibration and reproducibility data were obtained for MC-LR using LC-MS(2); 0.1-5.0 microg/ml, r2 = 0.992 (n = 3); % RSD < or =7.3 at 0.25 microg MC-LR/ml (n = 3). The detection limit (S/N = 3) was better than 0.1 ng. Water samples for microcystin analysis were first screened using protein phosphatase (PP) assays and positives were concentrated using C-18 solid-phase extraction. The developed method was applied to examine a lake in Ireland contaminated by Microcystis sp. and MC-LR and MC-LA were identified. 相似文献
159.
The field of environmental risk management is relatively new and has developed rapidly over the past several years. There has been, however, a significant lack of integration of seemingly dissimilar disciplines into a meaningful context for top management risk decisions—until now. A new holistic approach, centered on the ISO 14001 standard for environmental management systems, addresses many of the issues that have kept environmental risk management focused on technical rather than strategic issues. This article describes the risk management process, illustrates how the ISO 14001 standard can be used by organizations to integrate and assess technical environmental information, and shows how to place this information in a strategic risk management context. It also explains how key ISO 14001 concepts such as policy implementation, operational control, and continuous improvement form the basis of a systems approach, and why the systems approach is the preferred, cost-effective structure for controlling environmental risk. 相似文献
160.