全文获取类型
收费全文 | 437篇 |
免费 | 10篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 16篇 |
废物处理 | 20篇 |
环保管理 | 54篇 |
综合类 | 60篇 |
基础理论 | 143篇 |
环境理论 | 1篇 |
污染及防治 | 124篇 |
评价与监测 | 20篇 |
社会与环境 | 11篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 11篇 |
2022年 | 7篇 |
2021年 | 10篇 |
2020年 | 11篇 |
2019年 | 7篇 |
2018年 | 13篇 |
2017年 | 12篇 |
2016年 | 12篇 |
2015年 | 17篇 |
2014年 | 16篇 |
2013年 | 23篇 |
2012年 | 27篇 |
2011年 | 41篇 |
2010年 | 22篇 |
2009年 | 24篇 |
2008年 | 17篇 |
2007年 | 31篇 |
2006年 | 17篇 |
2005年 | 19篇 |
2004年 | 11篇 |
2003年 | 7篇 |
2002年 | 16篇 |
2001年 | 11篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1976年 | 9篇 |
1975年 | 4篇 |
1962年 | 1篇 |
1957年 | 1篇 |
1941年 | 1篇 |
1937年 | 3篇 |
1918年 | 1篇 |
排序方式: 共有452条查询结果,搜索用时 31 毫秒
391.
INTRODUCTION: Computer-based safety training is becoming more common and is being delivered to an increasingly aging workforce. Aging results in a number of changes that make it more difficult to learn from certain types of computer-based training. Instructional designs derived from cognitive learning theories may overcome some of these difficulties. METHODS: Three versions of computer-based respiratory safety training were shown to older and younger workers who then took a high and a low level learning test. RESULTS: Younger workers did better overall. Both older and younger workers did best with the version containing text with pictures and audio narration. DISCUSSION: Computer-based training with pictures and audio narration may be beneficial for workers over 45 years of age. IMPACT ON INDUSTRY: Computer-based safety training has advantages but workers of different ages may benefit differently. Computer-based safety programs should be designed and selected based on their ability to effectively train older as well as younger learners. 相似文献
392.
Jens Havskov Sørensen Alix Rasmussen Thomas Ellermann Erik Lyck 《Atmospheric environment (Oxford, England : 1994)》1998,32(24):101
During the first European Tracer Experiment (ETEX) tracer gas was released from a site in Brittany, France, and subsequently observed over a range of 2000 km. Hourly measurements were taken at the National Environmental Research Institute (NERI) located at Risø, Denmark, using two measurement techniques. At this location, the observed concentration time series shows a double-peak structure occurring between two and three days after the release. By using the Danish Emergency Response Model of the Atmosphere (DERMA), which is developed at the Danish Meteorological Institute (DMI), simulations of the dispersion of the tracer gas have been performed. Using numerical weather-prediction data from the European Centre for Medium-Range Weather Forecast (ECMWF) by DERMA, the arrival time of the tracer is quite well predicted, so also is the duration of the passage of the plume, but the double-peak structure is not reproduced. However, using higher-resolution data from the DMI version of the HIgh Resolution Limited Area Model (DMI-HIRLAM), DERMA reproduces the observed structure very well. The double-peak structure is caused by the influence of a mesoscale anti-cyclonic eddy on the tracer gas plume about one day earlier. 相似文献
393.
PCDDs, PCDFs and some related aromatic compounds were determined isomer specifically in sediments from the river Rhine and its tributaries, in order to study sources and environmental fate of these compounds. Additionally, waste water effluents from industries that unintentionally might coproduce PCDDs or PCDFs were analyzed. In all sediments and in some waste water effluents these compounds could be detected. Variations of the isomeric patterns of the PCDFs enabled a distinct industrial area, that was associated with PCB contamination to be identified. The contamination of sediments and organisms from the Dutch river Rhine delta with these compounds mainly could be attributed to the transboundary pollution of the river Rhine. 相似文献
394.
Robert Axelsson Per Angelstam Erik Degerman Sara Teitelbaum Kjell Andersson Marine Elbakidze Marcus K. Drotz 《Ambio》2013,42(2):215-228
Policies on economic use of natural resources require considerations to social and cultural values. In order to make those concrete in a planning context, this paper aims to interpret social and cultural criteria, identify indicators, match these with verifier variables and visualize them on maps. Indicators were selected from a review of scholarly work and natural resource policies, and then matched with verifier variables available for Sweden’s 290 municipalities. Maps of the spatial distribution of four social and four cultural verifier variables were then produced. Consideration of social and cultural values in the studied natural resource use sectors was limited. The spatial distribution of the verifier variables exhibited a general divide between northwest and south Sweden, and regional rural and urban areas. We conclude that it is possible to identify indicators and match them with verifier variables to support inclusion of social and cultural values in planning. 相似文献
395.
Per Angelstam Jean-Michel Roberge Robert Axelsson Marine Elbakidze Karl-Olof Bergman Anders Dahlberg Erik Degerman Sönke Eggers Per-Anders Esseen Joakim Hjältén Therese Johansson Jörg Müller Heidi Paltto Tord Snäll Ihor Soloviy Johan Törnblom 《Ambio》2013,42(2):229-240
Assessing ecological sustainability involves monitoring of indicators and comparison of their states with performance targets that are deemed sustainable. First, a normative model was developed centered on evidence-based knowledge about (a) forest composition, structure, and function at multiple scales, and (b) performance targets derived by quantifying the habitat amount in naturally dynamic forests, and as required for presence of populations of specialized focal species. Second, we compared the Forest Stewardship Council (FSC) certification standards’ ecological indicators from 1998 and 2010 in Sweden to the normative model using a Specific, Measurable, Accurate, Realistic, and Timebound (SMART) indicator approach. Indicator variables and targets for riparian and aquatic ecosystems were clearly under-represented compared to terrestrial ones. FSC’s ecological indicators expanded over time from composition and structure towards function, and from finer to coarser spatial scales. However, SMART indicators were few. Moreover, they poorly reflected quantitative evidence-based knowledge, a consequence of the fact that forest certification mirrors the outcome of a complex social negotiation process. 相似文献
396.
397.
Hongjuan Han Yonggen Chen Sven Erik Jørgensen Søren Nors Nielsen Weiping Hu 《Ecological modelling》2009
A system-dynamic model has been built to evaluate the competition between submerged macrophytes Potamogeton malaianus Miq. (PM) and filamentous green algae Spirogyra sp. (SP). The data background is based on a spring–summer and an autumn–winter experiment carried out in artificial field ponds. The experiments had the aim to acquire a knowledge base necessary to a successful restoration of submerged macrophyte vegetation in Lake Taihu, China by use of P. malaianus Miq. The model mainly focuses on variations in water volume; biomass dynamics of P. malaianus Miq., Spirogyra sp. and zoobenthos; nutrients cycling between water column, P. malaianus Miq., Spirogyra sp., zoobenthos, detritus and sediment. Sixteen state variables are included in the model: biomass of P. malaianus Miq., Spirogyra sp. and zoobenthos; nitrogen in sediments, detritus, in P. malaianus Miq., in Spirogyra sp. and zoobenthos; total dissolved nitrogen; phosphorus in sediments, detritus, in P. malaianus Miq., in Spirogyra sp. and in zoobenthos; total dissolved phosphorus, and water volume of the experiment pond. The calibration and validation of the model show a good accordance with the results of the spring–summer experiment and the autumn–winter experiment. 相似文献
398.
Valentin Amrhein Lars Erik Johannessen Lena Kristiansen Tore Slagsvold 《Behavioral ecology and sociobiology》2008,62(10):1633-1641
The costs and benefits of bird song are likely to vary among species, and different singing patterns may reflect differences
in reproductive strategies. We compared temporal patterns of singing activity in two songbird species, the blue tit (Cyanistes caeruleus) and the great tit (Parus major). The two species live side by side year round, and they have similar breeding ecology and similar rates of extra-pair paternity.
However, they differ in two aspects of reproductive strategy that may have an influence on song output: blue tits are facultatively
polygynous and have a fairly short breeding season with almost no second broods, whereas great tits are socially monogamous
but more commonly raise second broods. We found that great tit males continued singing at high levels during the egg-laying
and incubation periods, while monogamously paired blue tit males strongly reduced singing activity after the first days of
egg-laying by their female. Since males of both species sang much more intensely shortly before sunrise than after sunrise,
at midday or in the evening, this difference was most conspicuous at dawn. No differences in singing activity were found within
species when testing for male age. We suggest that in contrast to blue tits, great tit males continued singing after egg-laying
to defend the territory and to encourage the female for a possible second brood. 相似文献
399.
Filip Moldan Veronika Kronnäs Anders Wilander Erik Karltun Bernard J. Cosby 《Water, Air, & Soil Pollution: Focus》2004,4(2-3):139-160
The MAGIC model was calibrated to 143 lakes in Sweden, all of which are monitored in Swedish national monitoring programmes conducted by the University of Agricultural Sciences (SLU). Soil characteristics of the lake catchments were obtained from the National Survey of Forest Soils and Vegetation also carried out by SLU. Deposition data were provided by the Swedish Meteorological and Hydrological Institute (SMHI). The model successfully simulated the observed lake and soil chemistry at 133 lakes and their catchments. The fact that 85% of the lakes calibrated successfully without being treated in an individual way suggests that data gathered by the national monitoring programmes are suitable for modelling of soil and surface water recovery from acidification. The lake and soil chemistry data were then projected into the future under the deposition scenario based on emission reductions agreed in the Gothenburg protocol. Deposition of sulphur (sea salt corrected) was estimated to decrease from 1990 to 2010 by 65–73%; deposition of nitrogen was estimated to decrease by 53%. The model simulated relatively rapid improvements in lake water chemistry in response to the decline in deposition from 1990 to 2010, but the improvements levelled off once deposition stabilised at the lower value. There was a major improvement of simulated lake water charge balance acid neutralising capacity (ANC) from 1990 to 2010 in all lakes. The modelled lakes were divided into acidification sensitive and non-sensitive. The modelled sensitive lakes are representative of 20% of the most sensitive lakes in Sweden. By 2010, the ANC in the sensitive lakes was 10 to 50 μeq L-1 below estimated pre-industrial levels and did not increase much further from 2010 to 2040. Soils at the majority of the modelled catchments continued to lose base cations even after the simulated decline in acid deposition was complete, i.e. after the year 2010. Based on this model prediction, the acidification of the Swedish soils will in general not be reversed by the deposition reduction experienced over the last 10 years and expected to occur by the year 2010. 相似文献
400.
Dieter Heylen Wendt Müller Ton G. G. Groothuis Erik Matthysen 《Behavioral ecology and sociobiology》2012,66(2):287-293
In birds as in many other taxa, parasites can have deleterious effects on offspring development. Therefore, avian mothers
have evolved responses to counteract parasite virulence in offspring via transgenerational defense mechanisms that is the
transfer of immune-enhancing substances such as antibodies to their eggs. Another maternal pathway is suggested by the finding
that infested great tit mothers produced eggs with lower androgens, since these yolk androgens are immunosuppressive and potentially
affect parasite susceptibility of the nestlings. However, whether this pathway is a specific adaptation to infestation with
parasites that affect the offspring or an epiphenomenon of lower androgen production in the female due to the parasite effects
on the mother itself is as yet unclear. In this study we infested female great tits (Parus major) with sheep ticks (Ixodes ricinus), which are nonnidicolous ectoparasites with low vertical transmission capability, and evaluated the effects on yolk androgen
deposition. Tick-infested females did not significantly reduce their deposition of androgens (androstenedione (A4) and testosterone) compared to tick-reduced females, which is in contrast to a previous study showing a lowered deposition
of A4 and testosterone when females were exposed to the nidicolous hen flea. Thus, females alter their hormone deposition, and
thus likely offspring phenotype, when exposed to parasites that also form the parasitic environment of their offspring, but
not when temporarily infested with the field-dwelling sheep ticks with low transmission capability. This suggests that selection
favored the evolution of an adaptive transgenerational effect by acting mainly on the parasite-induced maternal effect. 相似文献