全文获取类型
收费全文 | 333篇 |
免费 | 14篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 23篇 |
废物处理 | 12篇 |
环保管理 | 53篇 |
综合类 | 32篇 |
基础理论 | 108篇 |
污染及防治 | 70篇 |
评价与监测 | 23篇 |
社会与环境 | 23篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2020年 | 10篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 8篇 |
2016年 | 14篇 |
2015年 | 9篇 |
2014年 | 10篇 |
2013年 | 36篇 |
2012年 | 15篇 |
2011年 | 17篇 |
2010年 | 9篇 |
2009年 | 6篇 |
2008年 | 23篇 |
2007年 | 20篇 |
2006年 | 22篇 |
2005年 | 15篇 |
2004年 | 9篇 |
2003年 | 7篇 |
2002年 | 9篇 |
2001年 | 7篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1969年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有349条查询结果,搜索用时 15 毫秒
21.
A factor analytic study of attitudinal structure and its impact on rural landowners' access policies
Previous research has shown that rural landowners' hunter access policies are determined in large part by their attitudes
towards hunters, legal liability, conservation, and economic incentives. The results of this study support this research and
indicate that East Texas, USA, landowners' decisions to allow or restrict access are based, in part, on attitudes toward hunter
behavior, hunting as a social activity, leasing as a management practice, and a perceived obligation toward wildlife stewardship.
Attitude-based profiles of landowners who adopted one of four access policies are compared. 相似文献
22.
R. Gerald Wright 《Environmental management》1984,8(2):121-124
Legislation settling the Alaska Native Lands Claims also resulted in the establishment of ten new parks and preserves in Alaska. This settlement was the result of a long and often bitter legislative struggle between pro- and antidevelopment groups. The planning history of the Wrangell-St. Elias National Park and Preserve is used as a case example of this debate. One particular source of conflict was the curtailment of sport hunting that would result under national park classification. A preserve classification was introduced to resolve this conflict. Data on wildlife resources and sport hunting were instrumental in defining the areas so classified. 相似文献
23.
24.
M. B. Blasius S. J. Kerkhoff R. S. Wright C. R. Cothern 《Journal of the American Water Resources Association》1972,8(4):704-714
ABSTRACT. The X-ray fluorescence method was used to analyze trace metals collected in particulate form on filter papers and from the ionic state by ion exchange filter papers. The samples were prepared by allowing water to pass through these filter papers. The procedures necessary for using the X-ray fluorescence method are described. A number of samples were taken from the Great Miami River in Dayton, Ohio over one year showing the presence of the following metals, Ca, Ti, Cr, Fe, Cu, Zn, Sr, and Cd. Elements in the periodic table between Ti and Cs were detectable to a sensitivity limit of the order of 30 ppb for metals in the particulate form and 0.4 ppm for metals in the ionic form. 相似文献
25.
26.
Howard BJ Wright SM Barnett CL Skuterud L Strand P 《Journal of environmental radioactivity》2002,60(1-2):209-220
The application of the critical loads methodology for radioactive contamination of Arctic and sub-arctic ecosystems, where natural and semi-natural food products are important components of the diet of many people, is proposed and discussed. The critical load is herein defined as the amount of radionuclide deposition necessary to produce radionuclide activity concentrations in food products exceeding intervention limits. The high transfer of radiocaesium to reindeer meat gives this product the lowest critical load, even though the intervention limit is relatively high compared with other products. Ecological half-lives of radiocaesium in natural and semi-natural products are often very long, and it is therefore important to take account of contamination already present in the event of an accident affecting areas where such products are important. In particular, the long ecological half-life for radiocaesium in moose meat means that the critical load is highly sensitive to prior deposition. An example of the potential application of the method for emergency preparedness is given for the Chernobyl accident. 相似文献
27.
Ascidian specimens were collected from the Indian River Lagoon, Florida, USA, in November 1987. Eudistoma olivaceum (Van Name) was fouled by only two species of epifaunal invertebrates and the percent cover of epibionts was negligible. Colonies of E. capsulatum (Van Name) were fouled by up to 17 species of epifaunal invertebrates, epibionts covered an average of 12.5% of the surface area of these colonies. Extracts of E. olivaceum exhibited potent cytotoxic, antimicrobial and antiviral activity in laboratory bioassays, while the activity of extracts of E. capsulatum was insignificant. The toxicity of extracts of each ascidian was negatively related to the percent cover of fouling organisms. Surface acidity of each ascidian was positively related to the percent cover of epibionts: E. olivaceum was nearly neutral (pH=6), while E. capsulatum was highly acidic (pH=1 to 2). Larval settlement and growth of ancestrulae of the cheilostome bryozoan Bugula neritina (Linnaeus) were inhibited at very low concentrations of crude extract of E. olivaceum. Crude extracts of E. capsulatum inhibited settlement and growth of B. neritina only at concentrations of approximately an order of magnitude greater than those of E. olivaceum. Differences in the degree to which these congeneric ascidians are fouled is related to differences in the chemical defenses they possess. Acidity is not an effective inhibitor of settlement by epifaunal invertebrates. 相似文献
28.
29.
Determining the scale of larval dispersal and population connectivity in demersal fishes is a major challenge in marine ecology.
Historically, considerations of larval dispersal have ignored the possible contributions of larval behaviour, but we show
here that even young, small larvae have swimming, orientation and vertical positioning capabilities that can strongly influence
dispersal outcomes. Using young (11–15 days), relatively poorly developed (8–10 mm), larvae of the pomacentrid damselfish,
Amblyglyphidodon curacao (identified using mitochondrial DNA), we studied behaviour relevant to dispersal in the laboratory and sea on windward and
leeward sides of Lizard Island, Great Barrier Reef. Behaviour varied little with size over the narrow size range examined.
Critical speed was 27.5 ± 1.0 cm s−1 (30.9 BL s−1), and in situ speed was 13.6 ± 0.6 cm s−1. Fastest individuals were 44.6 and 25.0 cm s−1, for critical and in situ speeds, respectively. In situ speed was about 50% of critical speed and equalled mean current speed.
Unfed larvae swam 172 ± 29 h at 8–10 cm s−1 (52.0 ± 8.6 km), and lost 25% wet weight over that time. Vertical distribution differed between locations: modal depth was
2.5–5.0 and 10.0–12.5 m at leeward and windward sites, respectively. Over 80% of 71 larvae observed in situ had directional
swimming trajectories. Larvae avoided NW bearings, with an overall mean SE swimming direction, regardless of the direction
to nearest settlement habitat. Larvae made smaller changes between sequential bearings of swimming direction when swimming
SE than in other directions, making it more likely they would continue to swim SE. When swimming NW, 62% of turns were left
(more than in other directions), which would quickly result in swimming direction changing away from NW. This demonstrates
the larvae knew the direction in which they were swimming and provides insight into how they achieved SE swimming direction.
Although the cues used for orientation are unclear, some possibilities seemingly can be eliminated. Thus, A. curacao larvae near Lizard Island, on average swam into the average current at a speed equivalent to it, could do this for many hours,
and chose different depths in different locations. These behaviours will strongly influence dispersal, and are similar to
behaviour of other settlement-stage pomacentrid larvae that are older and larger. 相似文献
30.
Two basic and competing approaches for measuring the benefits of pollution abatement have found support in the recent literature-the property value approach and the health damage function approach. The purpose of this paper is to show that conditions will often exist when the property value approach will not accurately measure all benefits and conditions will always be present that cause the health damage function approach to underestimate benefits. In general, neither approach can stand alone. It is possible, however, that the two approaches can be combined in such a way as to improve the measurement of abatement benefits. We present an approach for combining these two methods and do so by introducing an “information coefficient” that measures the degree of knowledge about pollution effects held by the public. Approaches to estimating the information coefficient are suggested. 相似文献