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681.
Dalgaard T Olesen JE Petersen SO Petersen BM Jørgensen U Kristensen T Hutchings NJ Gyldenkærne S Hermansen JE 《Environmental pollution (Barking, Essex : 1987)》2011,159(11):3193-3203
Greenhouse gas (GHG) emissions from agriculture are a significant contributor to total Danish emissions. Consequently, much effort is currently given to the exploration of potential strategies to reduce agricultural emissions. This paper presents results from a study estimating agricultural GHG emissions in the form of methane, nitrous oxide and carbon dioxide (including carbon sources and sinks, and the impact of energy consumption/bioenergy production) from Danish agriculture in the years 1990–2010. An analysis of possible measures to reduce the GHG emissions indicated that a 50–70% reduction of agricultural emissions by 2050 relative to 1990 is achievable, including mitigation measures in relation to the handling of manure and fertilisers, optimization of animal feeding, cropping practices, and land use changes with more organic farming, afforestation and energy crops. In addition, the bioenergy production may be increased significantly without reducing the food production, whereby Danish agriculture could achieve a positive energy balance. 相似文献
682.
齐建国 《再生资源与循环经济》2011,4(11)
介绍了碳循环与碳汇产业的科学内涵及其在我国的发展现状与目标,提出“十二五”期间应大力推广的几种碳循环与碳汇产业的成功模式,以及促进碳循环和碳汇产业发展的对策建议。 相似文献
683.
Timekeeping in the honey bee colony: integration of circadian rhythms and division of labor 总被引:1,自引:0,他引:1
Darrell Moore Jennifer E. Angel Iain M. Cheeseman Susan E. Fahrbach Gene E. Robinson 《Behavioral ecology and sociobiology》1998,43(3):147-160
The daily patterns of task performance in honey bee colonies during behavioral development were studied to determine the
role of circadian rhythmicity in age-related division of labor. Although it is well known that foragers exhibit robust circadian
patterns of activity in both field and laboratory settings, we report that many in-hive tasks are not allocated according
to a daily rhythm but rather are performed 24 h per day. Around-the-clock activity at the colony level is accomplished through
the performance of some tasks by individual workers randomly with respect to time of day. Bees are initially arrhythmic with
respect to task performance but develop diel rhythmicity, by increasing the occurrence of inactivity at night, prior to becoming
foragers. There are genotypic differences for age at onset of rhythmicity and our results suggest that these differences are
correlated with genotypic variation in rate of behavioral development: genotypes of bees that progressed through the age polyethism
schedule faster also acquired behavioral rhythmicity at an earlier age. The ontogeny of circadian rhythmicity in honey bee
workers ensures that essential in-hive behaviors are performed around the clock but also allows the circadian clock to be
engaged before the onset of foraging.
Received: 6 October 1997 / Accepted after revision: 28 March 1998 相似文献
684.
The relation of age to division of labor was assessed in a primitively eusocial wasp, Ropalidia marginata. The performance of four functionally significant tasks was analyzed. It was found that age has a definite correlation with
division of labor, since wasps performed tasks in a distinct sequence in their life with successive tasks being initiated
at significantly older ages. Age of a wasp was measured in absolute terms and also relative to other individuals in the colony.
Probability of performance of a given task relative to other tasks (PTP) and absolute rates at which tasks were performed
per unit time (FTP) both showed clear age-dependent patterns, confirming the association of age with division of labor. The
proportion of variance explained for both PTP and FTP was significantly higher with relative age than with absolute age. Interindividual
interactions were found to be a potential mechanism through which wasps can determine their relative age. The advantages of
work organization depending on relative age and the constraints imposed by absolute age are discussed.
Received: 2 April 1997 / Accepted after revision: 20 July 1997 相似文献
685.
686.
加速碳酸化技术对城市垃圾焚烧飞灰重金属稳定性影响研究 总被引:2,自引:2,他引:0
对南方某城市生活垃圾焚烧厂新鲜焚烧飞灰对CO2的吸收及其碳酸化的过程进行了研究,实验从水分添加量、CO2的分压等因素,考察了飞灰中重金属Pb的稳定化效果,并利用X射线衍射实验(XRD)、扫描电镜实验(SEM)对反应机理进行了分析.结果表明,不添加水分时,焚烧飞灰对CO2的吸收效果较差;当水分添加量大于10%时,焚烧飞灰对CO2的吸收效果较好.焚烧飞灰对纯CO2的吸收效果较好,空气中的CO2含量较低,在反应1 d后吸收效果不是十分明显.XRD实验结果表明,CO2的吸收会使焚烧飞灰中大量的Ca(OH)2与CO2反应转化为CaCO3,从而降低焚烧飞灰的碱性;部分重金属的氧化物会被碳酸化成生相应的碳酸盐.SEM实验结果表明,经过碳酸化处理后的飞灰颗粒表面生成了片状和圆柱状的晶体物质. 相似文献
687.
长江口盐沼植物对营养盐和重金属的吸收、分布与滞留研究 总被引:2,自引:0,他引:2
测定3种盐沼植物体内TN、TP、重金属Cu、Zn、Pb和Cd的含量,计算了3种盐沼植物地上部分TN、TP和重金属库的大小.结果表明,3种盐沼植物在养分的分配模式上显著不同,3种盐沼植物地上部分重金属含量均低于地下部分;互花米草地上部分的养分库和重金属库均大于芦苇和海三棱镳草,表明其对养分和重金属的吸收与滞留效率更高.如果从湿地植物净化的角度来考虑,收获互花米草对河口环境的净化作用最佳,特别对P的去除效率最高;但另一方面,互花米草的入侵将会显著改变长江口湿地生态系统的生物地球化学循环过程,如提高沉积物中重金属的生物可利用性,有可能把更多的重金属输入河口水体和食物网,使湿地成为重金属的源而不是汇. 相似文献
688.
689.
690.
Susumu Shimura Isamu Yokota Yoshitaka Nitta 《Journal of Material Cycles and Waste Management》2001,3(1):48-59
Developing nations have various problems regarding municipal solid waste (MSW). Therefore, to carry out a systematic review
of the MSW problems in the target area and to formulate a well-considered management plan, it is extremely important to understand
the present MSW flow in the region. One of the authors participated in the nine solid waste management (SWM) studies in developing
nations undertaken under the technical cooperation program of the Japan International Cooperation Agency (JICA). Based on
these studies, this paper reviews the results of research in developing countries regarding different MSW streams, the factors
that cause the differences, and the elements considered to have the most impact on those streams. This research identifies
several issues regarding MSW streams in developing nations. The MSW generation rate per capita in developing countries is
generally said to grow in proportion to the GNP. However, the findings of this research show no correlation between the two;
instead, there is a relationship between the GNP and the collection rate. To formulate proper future MSW management plans
in countries with low collection rates, it is very important to forecast the rates of self-disposed and recycled waste, and
their fluctuations. These are affected by urban structure, collection services, etc.
Received: January 27, 2000 / Accepted: July 19, 2000 相似文献