全文获取类型
收费全文 | 42539篇 |
免费 | 390篇 |
国内免费 | 213篇 |
专业分类
安全科学 | 1221篇 |
废物处理 | 1582篇 |
环保管理 | 6040篇 |
综合类 | 6599篇 |
基础理论 | 11852篇 |
环境理论 | 24篇 |
污染及防治 | 11201篇 |
评价与监测 | 2537篇 |
社会与环境 | 1795篇 |
灾害及防治 | 291篇 |
出版年
2022年 | 277篇 |
2021年 | 344篇 |
2020年 | 280篇 |
2019年 | 397篇 |
2018年 | 564篇 |
2017年 | 556篇 |
2016年 | 845篇 |
2015年 | 737篇 |
2014年 | 1066篇 |
2013年 | 3305篇 |
2012年 | 1260篇 |
2011年 | 1801篇 |
2010年 | 1458篇 |
2009年 | 1521篇 |
2008年 | 1826篇 |
2007年 | 1931篇 |
2006年 | 1706篇 |
2005年 | 1439篇 |
2004年 | 1435篇 |
2003年 | 1354篇 |
2002年 | 1354篇 |
2001年 | 1688篇 |
2000年 | 1209篇 |
1999年 | 750篇 |
1998年 | 595篇 |
1997年 | 588篇 |
1996年 | 635篇 |
1995年 | 670篇 |
1994年 | 611篇 |
1993年 | 558篇 |
1992年 | 534篇 |
1991年 | 511篇 |
1990年 | 516篇 |
1989年 | 534篇 |
1988年 | 465篇 |
1987年 | 420篇 |
1986年 | 371篇 |
1985年 | 401篇 |
1984年 | 393篇 |
1983年 | 429篇 |
1982年 | 438篇 |
1981年 | 391篇 |
1980年 | 332篇 |
1979年 | 371篇 |
1978年 | 301篇 |
1977年 | 254篇 |
1976年 | 257篇 |
1975年 | 254篇 |
1973年 | 238篇 |
1972年 | 273篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
271.
Alan J. Gross 《Environmetrics》1995,6(4):403-412
The United States Environmental Protection Agency (EPA), in its recent risk assessment dealing with environmental tobacco smoke (ETS), estimated the annual number of lung cancer deaths in non-smokers (including both never-smokers and former-smokers who have quit smoking for at least five years) associated with ETS exposure to be between 2500 and 3300 in the United States. This estimate is based on a number of assumptions that are not supported by the existing data. Moreover, the range presented by EPA fails to take into account the uncertainties involved in this estimate. This paper discusses the significant assumptions that underlie any quantitation of lung cancer risks allegedly due to ETS exposure, and explores the uncertainties of each assumption and how each uncertainty affects the summary estimate. The author concludes that any range must encompass an estimate of zero deaths, and that the uncertainties are so great as to cast serious doubt on the use of any quantitative estimate. 相似文献
272.
273.
274.
E. J. Anthony 《Greenhouse Gases: Science and Technology》2011,1(1):36-47
Calcium looping technology is a promising new technique for high‐temperature scrubbing of CO2 from flue gas and syngases. Current economic projections suggest it might be able to capture CO2 at costs of ∼$20/ton of avoided CO2. Nonetheless there are questions about the long‐term behavior of natural sorbents in such systems, and there is substantial R&D being done on this technology worldwide to answer questions about whether the performance of natural sorbents can be improved, or whether it would be better to use synthetic ones. The current period is particularly interesting as the first pilot plants and demonstration units capable of operating continuously are now coming on stream, and if successful these will lead to large‐scale industrial demonstrations of the technology in the next 10 to 15 years. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd 相似文献
275.
Verhaltensversuche zur Funktion der Lorenzinischen Ampullen 总被引:1,自引:0,他引:1
276.
277.
278.
279.
Land reclamation techniques that incorporate habitat features for herptofaunal wildlife have received little attention. We
assessed the suitability of a wetland, constructed for the treatment of mine-water drainage, for supporting herptofaunal wildlife
from 1988 through 1990 using diurnal and nocturnal surveys. Natural wetlands within the surrounding watershed were also monitored
for comparison. The treatment wetland supported the greatest abundance and species richness of herptofauna among the sites
surveyed. Abundance was a function of the frog density, particularly green frogs (Rana clamitans) and pickerel frogs (R. palustris), while species richness was due to the number of snake species found. The rich mix of snake species present at the treatment
wetland was believed due to a combination of an abundant frog prey base and an amply supply of den sites in rock debris left
behind from earlier surface-mining activities. Nocturnal surveys of breeding male frogs demonstrated highest breeding activity
at the treatment wetland, particularly for spring peepers (Hyla crucifer). Whole-body assays of green frog and bullfrog (R. catesbeiana) tissues showed no differences among sites in uptake of iron, aluminum, and zinc; managanese levels in samples from the treatment
wetland were significantly lower than those from natural wetlands. These results suggest that wetlands established for water
quality improvement can provide habitat for reptiles and amphibians, with the species composition dependent on the construction
design, the proximity to source populations, and the degree of acidity and heavy-metal concentrations in drainage waters. 相似文献
280.
Voluntary environmental reporting on the progress achieved against policy objectives is an emerging trend in industry and business and is recognized as a valuable aid in implementing policy and improving environmental management systems. Environmental reporting in the UK, has a whole range of formats including PERI, GEMI, WICE and EMAS, with the last, in particular, aiming to improve the level of environmental stewardship and to increase the flow of environmental information to audiences both internally and externally. Higher education institutions globally have been slow to respond in this respect and there is much that they can learn from corporate environmental reporting. An environmental policy is not sufficient proof of commitment for those institutions who have signed the global Talloires Declaration or the European COPERNICUS Charter: demonstrable progress in policy implementation is essential. The environmental management systems that higher education institutions adopt or create and the ways in which their environmental information is collated are of great significance, but the medium selected for the report is perhaps one of the most important aspects to consider. Those institutions such as the University of Sunderland, UK who are using the World Wide Web have been able to produce a flexible, hypertext-linked service on request with inbuilt feedback mechanisms containing varied, up-to-date, comprehensive and well-structured environmental information signposted to external pro-active institutions and agencies. These reports have unique educational angles and reveal links and networks that are naturally more pervasive and far-reaching in their scope and impact and could well provide a key way forward to practical and sustainable environmental reporting into the millennium. 相似文献