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991.
An extensive road system with rapidly increasing traffic produces diverse ecological effects that cover a large land area.
Our objective was to evaluate the effect of roads with different traffic volumes on surrounding avian distributions, and its
importance relative to other variables. Grassland bird data (5 years) for 84 open patches in an outer suburban/rural landscape
near Boston were analyzed relative to: distance from roads with 3000–8000 to >30,000 vehicles/day; open-habitat patch size;
area of quality microhabitat within a patch; adjacent land use; and distance to other open patches. Grassland bird presence
and regular breeding correlated significantly with both distance from road and habitat patch size. Distance to nearest other
open patch, irrespective of size, was not significant. Similarly, except for one species, adjacent land use, in this case
built area, was not significant. A light traffic volume of 3000–8000 vehicles/day (local collector street here) had no significant
effect on grassland bird distribution. For moderate traffic of 8000–15,000 (through street), there was no effect on bird presence
although regular breeding was reduced for 400 m from a road. For heavier traffic of 15,000–30,000 (two-lane highway), both
bird presence and breeding were decreased for 700 m. For a heavy traffic volume of ≥30,000 vehicles/day (multilane highway),
bird presence and breeding were reduced for 1200 m from a road. The results suggest that avian studies and long-term surveys
near busy roads may be strongly affected by traffic volume or changes in volume. We conclude that road ecology, especially
the effects extending outward >100 m from roads with traffic, is a sine qua non for effective land-use and transportation policy. 相似文献
992.
GONTRAN F. BAGE RÉJEAN SAMSON BERNARD SINCLAIR-DESGAGNÉ 《Environmental management》2002,30(6):0807-0815
A technicoeconomic model is developed to select an optimal strategy for the remediation of a contaminated site and to determine
the value of this remediation strategy. The model is an extension of actual cost–benefit analysis, with consideration of “irreversible”
remediation technology choices, technology effectiveness, and uncertainty on the site's level of contamination. The model
considers the possibility of reducing uncertainty by both acquiring more and better information on the level of contamination
and by offering the decision-maker the opportunity to reevaluate his decision and switch to a more appropriate technology.
It is believed that this model will help decision-makers in the selection of a remediation strategy by presenting all potentially
feasible strategies, and how uncertainty on the site's level of contamination affects these strategies. 相似文献
993.
Human (managerial) actions affect the survival probabilities of the keystone species of an ecological–economic system. In turn, the well-being of these keystone species translates into the well-being or the resilience of the underlying ecological–economic system. What are the theoretical connections between human actions, keystone species survival, and the resilience of ecological–economic systems? In this note, we construct a simple stochastic model to draw out the links between this trinity. 相似文献
994.
The sacred groves along the forest belts of south India, which were traditionally managed by village communities, are gradually disappearing. This study conducts an analysis of how this community‐based resource management institution has evolved over time and what socio‐economic factors have caused its gradual disintegration. Commercial agriculture, changing demographics and weak property‐rights systems are found to be some of the enabling factors. While the grass‐roots enthusiasm to save the sacred groves is still alive, government action is needed to strengthen the traditional village organizations, which are still perhaps in the best position to manage local resources. Several economic and financial incentive mechanisms at the local level that might lead to more efficient and equitable resource use outcomes are suggested. 相似文献
995.
In Europe targets have been laid down by EU legislation for the recycling rate of end-of-life vehicles to be achieved within the nearby future. It is illustrated in this paper that the definition of the recycling rate and the realisation of the imposed targets are very much dependent on different parameters such as the changing lifetime of the product and product design. It may seem obvious that the recycling rate is determined by various time-varying factors, however, this paper endeavours to describe and quantify the role of these factors on the recycling rate over time by the use of a dynamic systems model. This model permits the prediction of the recycling rate as a function of the numerous presented parameters, changing design scenarios etc. In addition, different definitions of the recycling rate will be presented and discussed. This will lead to a better understanding of the parameters affecting the recycling system and a more precise understanding of the recycling targets and their realisation as imposed by EU legislation. This paper focuses on cars, but the discussion and the definitions derived are equally valid for any end-of-life product. 相似文献
996.
Jacob J. Burke 《Natural resources forum》2000,24(2):123-136
The paper suggests that the expansion of irrigated agriculture in the 20th century has de-coupled the water user from the inherent risk of exploiting both surface and groundwater resources. The apparent reliability of storage and conveyance infrastructure and the, relative cheapness and flexibility of groundwater exploitation offered by mechanised drilling and pumping have sheltered the end user from natural hydrological risk. The imperative for in-field irrigation efficiency has been effectively removed since the physical and economic management of the resource is determined by command area authorities or, in the case of some groundwater pumping, by the performance of power utilities, who have no direct interest in integrated resource conservation. As a result, the resource base has been degraded, and in some cases irreparable damage has occurred. It is argued that the rigidity of the resource management in many irrigation systems is not attuned to the inherent variability of natural systems upon which they depend. Further, the paper argues that irrigation management systems can work toward sustainability by spreading risk equitably, and transparently, amongst the resource regulators, managers and users. This has to involve a much more flexible approach to natural resource management that is conditioned not only by natural parameters, but also by the socio-economic settings. A range of examples highlights the variability and scale issues involved. 相似文献
997.
箱形长钢梁内焊接危害分析与对策 总被引:2,自引:0,他引:2
大跨度起重机箱形梁,因结构强度的要求,需要从两端进入梁内施焊。由于截面小、长度大,作业中产生大量烟尘、毒气,不能及时排出,严重损害工人身体健康。特别在高温季节,焊接热又使梁内温度增高,操作者闷热难忍,危害身心健康,影响工作效率。本文在实验研究基础上,分析了箱形长钢梁内多人焊接时,产生的烟尘、毒气及其分布情况,并“以人为中心”,剖析各种解决焊接危害技术的特点,提出适用于截面在1~2m~2、长度在30~50m范围的钢梁内多人施焊时的排烟降温对策。 相似文献
998.
J. I. Bakker 《Journal of Agricultural and Environmental Ethics》1990,3(1):50-88
This is an examination of the significance of Gandhi's social philosophy for development. It is argued that, when seen in light of Gandhi's social philosophy, the concepts of appropriate technology (A.T.) and basic needs take on new meaning. The Gandhian approach can be identified with theoriginal "basic needs" strategy for international development (Emmerij, 1981). Gandhi's approach helps to provide greater equity, or "distributive justice," by promoting technology that is appropriate to "basic needs" (food, clothing, shelter, health and basic education). Gandhi's social philosophy (Erikson, 1968; Roy, 1985) has been neglected by most development specialists, with only a few exceptions (e.g., Chambers, 1983; Charles, 1983). This analysis attempts to draw out some aspects of M.K. Gandhi's background and his thinking aboutswadeshi (i.e. local self-reliance and use of local knowledge and abilities) andswaraj (i.e. independent development that leads to equity and justice). Gandhi's ideas, which emerged out of an "Indic" meta-cultural background, are based on an emphasis on equity. Gandhi's syncretic Indic background includes a belief in what Bateson (1972), writing about Bali, Indonesia, has called the "steady state." Development activities should be carried out in a phased manner that does not disturb the beneficial aspects of dynamic equilibrium, but that does promote "positive development." A.T. is particularly useful within the context of a basic needs approach to international development because use of A.T. is probably more likely to lead to equitable growth. The "economic growth" strategy, utilizing "advanced technology" (or even "high tech") exclusively, has caused unemployment and has not led to effective "trickle down," much less "high mass consumption." In many developing countries the poorest 20% of the population are worse off in 1990 than they were in 1980. By making use of the "advantage of backwardness" (Veblen, 1966) and viewing development in terms of long-term impacts, a basic needs approach using A.T. is more likely to lead to a positive impact on third world food systems than a pure "economic growth" strategy.Paper presented at the Guelph Ethics & Technology Conference: Workshop on Technology and Ethical Choice in the Food Systems: Agriculture Workshop on The Impact of Agricultural Technology on Third World Food Systems. October 27, 1989, University of Guelph, Guelph, Ontario, Canada. 相似文献
999.
The recycling sector in India, which consists of a comprehensive trade and production sector, is rather complex. Nevertheless, it creates important benefits for both the economy and the environment. In order to comprehend the system, a case study has been performed on the recycling sector (paper, plastic, glass and non-ferrous metal) in Bangalore (India), focussing on the market structure, the scale of operation, employment effects, constraints, and recent developments. It was found that this highly competitive and labour-intensive industry is largely dependent on cheap labour and the supply of solid waste from the local trade system. Its mostly informal nature results from the ‘unregisteredness’ of the materials. Consequently, government involvement is avoided as much as possible. With present growth rates, prospects of recycling in Bangalore are advancing. Yet, problems such as lack of supply and loss of quality emerge. Therefore, quality control and market conditions should be improved. 相似文献
1000.
David Seckler R. K. Sampath S. K. Raheja 《Journal of the American Water Resources Association》1988,24(4):855-860
ABSTRACT: This paper presents a statistically valid index for measuring the performance of irrigation systems. The index is applied to a sample of 39 farms on a watercourse under the warabandi system of irrigation management in India. It is found that while the farmers in fact irrigated almost exactly the total amount of irrigated area as designed, inter-farm variations were considerable. The index shows that the degree of error of managerial effectiveness of irrigation on this watercourse is 20 percent. Therefore it is concluded that the system is performing at 80 percent effectiveness. 相似文献