全文获取类型
收费全文 | 557篇 |
免费 | 4篇 |
国内免费 | 8篇 |
专业分类
安全科学 | 9篇 |
废物处理 | 26篇 |
环保管理 | 53篇 |
综合类 | 87篇 |
基础理论 | 138篇 |
环境理论 | 4篇 |
污染及防治 | 191篇 |
评价与监测 | 30篇 |
社会与环境 | 31篇 |
出版年
2023年 | 7篇 |
2022年 | 7篇 |
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 3篇 |
2018年 | 21篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 13篇 |
2014年 | 20篇 |
2013年 | 44篇 |
2012年 | 20篇 |
2011年 | 48篇 |
2010年 | 30篇 |
2009年 | 34篇 |
2008年 | 25篇 |
2007年 | 41篇 |
2006年 | 31篇 |
2005年 | 21篇 |
2004年 | 30篇 |
2003年 | 22篇 |
2002年 | 24篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1998年 | 12篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1966年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1960年 | 2篇 |
1959年 | 1篇 |
1957年 | 2篇 |
1956年 | 2篇 |
1955年 | 4篇 |
1954年 | 1篇 |
1952年 | 1篇 |
1951年 | 1篇 |
1922年 | 3篇 |
排序方式: 共有569条查询结果,搜索用时 250 毫秒
391.
This paper reports the findings of a study that investigated the relationship between different kinds of career management activities, the psychological contract, and outcomes of psychological contract fulfillment. The study tested a series of linked hypotheses which propose that individual career management behavior is associated with the experience of organizational career management help, which is related to fulfillment of the psychological contract. Fulfillment of the psychological contract in turn is linked to organizational commitment and is associated with behaviors at work, including absenteeism, turnover, and independent ratings of job performance. The findings provide some support for these proposed links. As a result, the paper makes four contributions to the psychological contract and careers literature: first, it shows that both individual and organizational career management behaviors are linked to psychological contract fulfillment; second, organizational career management help is associated with affective commitment and job performance; third, psychological contract fulfillment plays a key role in mediating the relationship between career management help and such attitudes and behaviors; and fourth, organizational commitment may mediate between psychological contract fulfillment and individual career management behavior aimed at furthering the career outside the organization. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
392.
Strongly decreasing atmospheric emissions and acidic deposition during the 1990s have initiated chemical reversal from acidification
in several drinking-water reservoirs of the Erzgebirge, SE Germany. We studied responses of phytoplankton, zooplankton and
fish stocks in five reservoirs and at enclosure scale after experimental neutralization of 1,200 m3 of lake water. About 4 months after this treatment, diatoms and cryptomonads replaced the predominating chrysophytes and
dinoflagellates. The colonization by acid-sensitive species of green algae, cryptomonads, rotifers and Cladocera (e.g. Bosmina longirostris) is explained by the occurrence of dormant stages or by survival of individuals in very low abundances. Analogous to the
enclosure experiment, three reservoirs showed significantly (p < 0.01) falling trends of chlorophyll a and phytoplankton biovolume, mainly due to the decline of dinoflagellates. Picoplankton and diatoms increased slightly in
two reservoirs. The zooplankton communities were dominated by rotifers and small Cladocera. Representatives of the genus Daphnia were lacking. Two reservoirs were re-colonized by zooplanktivorous fish populations of either perch (Perca fluviatilis) or sunbleak (Leucaspius delineatus). The latter exhibited extremely high fluctuating abundance and biomass and even suffered from a population crash. This natural
mortality was caused by a limited food supply. Hence, severe top-down control may delay the recovery of larger zooplankton
species like daphnids. Fishery management comprising the introduction of predatory fishes can help to control zooplanktivorous
fish populations and to prevent their mass mortality. 相似文献
393.
394.
Photo-Fenton treatment of water containing natural phenolic pollutants 总被引:10,自引:0,他引:10
Gernjak W Krutzler T Glaser A Malato S Caceres J Bauer R Fernández-Alba AR 《Chemosphere》2003,50(1):71-78
Phenolic compounds are known to be present in high concentrations in various types of agro-industrial wastes. As they are highly biorecalcitrant, the possibility of treatment by advanced oxidation processes should be investigated. In this work, six model phenolic compounds (vanillin, protocatechuic acid, syringic acid, p-coumaric acid, gallic acid and L-tyrosine) were chosen for a demonstration of degradation by photo-Fenton reaction, under artificial light in laboratory experiments in Vienna and under sunlight in pilot-plant experiments at the Plataforma Solar de Almería in Spain. All compounds were completely mineralised. No non-degradable intermediates were produced, either in experiments with single substances or in a more complex matrix of a mixture of phenolic compounds. The expected selectivity of the photo-Fenton reaction for aromatic compounds was proven by comparison of the decrease in total organic carbon with the removal of total phenolic content. 相似文献
395.
Determination of malic acid and other C4 dicarboxylic acids in atmospheric aerosol samples 总被引:2,自引:0,他引:2
An ion chromatographic method was developed which is able to separate five unsubstituted and hydroxy C4 dicarboxylic acids, succinic, malic, tartaric, maleic and fumaric acid, besides the other unsubstituted C2-C5 dicarboxylic acids, oxalic, malonic and glutaric acids, as well as inorganic ions in samples extracted from atmospheric particulate matter. By the application of this method it was found for both rural and urban sites and for various types of air masses that in the summer-time malic acid is the most prominent C4 diacid (64 ng m(-3) by average), exceeding succinic acid concentration (28 ng m(-3) by average) considerably. In winter-time considerably less, a factor of 4-15, C4 acids occurred and succinic acid was more concentrated than malic acid. Tartaric, fumaric and maleic acids were less concentrated (5.1, 5.0 and 4.5 ng m(-3) by average, respectively). Tartaric acid was observed for the first time in ambient air. The results indicate that in particular anthropogenic sources are important for the precursors of succinic, maleic and fumaric acids. Biogenic sources seem to influence the occurrence of malic acid significantly. 相似文献
396.
Variation of nutrient and metal concentrations in aquatic macrophytes along the Rio Cachoeira in Bahia (Brazil) 总被引:6,自引:0,他引:6
The use of cuprous fungicides in cocoa production in the southern part of the state of Bahia (Brazil) for decades has caused an accumulation of copper in various components of the cocoa plantations, and a contamination of regional freshwater ecosystems is suspected. Urban and industrial sources are supposed to contribute to water pollution and eutrophication of the Rio Cachoeira, the main river in this region. In order to study the metal contamination and nutritional status of this freshwater ecosystem, samples of the aquatic macrophytes Eichhornia crassipes and Pistia stratiotes were collected at seven sites along the river course. The samples were analysed for their copper, aluminium, chromium, nitrogen and phosphorus concentrations. The levels of heavy metals increased in the downstream direction, particularly in the roots of water hyacinth. A dramatic increase of nitrogen and phosphorus concentrations in water as well as in plant tissues was found in samples collected downstream from the city of Itabuna. Metal input and eutrophication were attributed to agricultural, industrial and urban sources in the region. Biomonitoring of the water quality using aquatic macrophytes as accumulative indicator plants is recommended in addition to chemical water analyses. 相似文献
397.
Andreas Kemna Andrew Binley Frederick Day-Lewis Andreas Englert Bülent Tezkan et al. 《Environmental geochemistry and health》1991,13(3):152
The Society for Environmental Geochemistry and Health Tenth European MeetingUniversity of Edinburgh April 12–15, 1992 相似文献
398.
This paper examines the evolution of the control by the state of mining and smelting from 1975 to 1989. In 1950, there was little state-owned mining capacity outside the centrally planned economies. A wave of nationalizations of mine assets swept over the developing countries in the late 1960s and early 1970s. State control continued to rise, in developing countries as well as in the developed market economy countries, until the mid-1980s, when the trend reversed. At present some 20% of Western world mineral production is state controlled. The level of control is highest for those minerals mined mainly in the developing countries, and lowest for those minerals mined mainly in the developed market economy countries. The current trend is toward privatization of state-owned mining enterprises in developed countries and it is expected that as the 1990s progress, privatization of such enterprises will also begin to take place in developing countries. 相似文献
399.
For CO2 capture and storage (CCS) to succeed as a mitigation strategy, political commitment is one of several prerequisites. This article offers an appraisal of political commitment to a CCS strategy among high-income countries in Europe and North America: Which governments are committed, and what particular interests and concerns do they seek to accommodate by supporting CCS? In order to answer these questions, new data are reported on government CCS research, development and demonstration (RD&;D) budgets. RD&;D budgets divided by GDP is used as an indicator of political commitment, and explanations are sought for cross-national differences. The analysis shows that fossil fuels reserves and extraction within a country has a very strong bearing on funding levels. Likely explanations include the potential for combining CCS with enhanced resource recovery. All large economies (population >50 million) have a funding program. The smaller states that provide funding (Norway, Canada, the Netherlands) have the highest funding levels relative to GDP. These findings suggest that high-income petroleum producing countries are likely to be leaders in promoting CCS and a favorable regulatory environment. The fact that all large, high-income countries in the two regions now display some interest in CCS further improves its political outlook. 相似文献
400.