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91.
Energy planners in developing countries have traditionally sought to meet their nations' growing electricity demands by adding more generation and transmission capacity. But as the foreign investment situation became critical in the 1980s, private investment and system efficiency improvement programmes began to garner interest. One of the most promising system efficiency improvement options is load management, which uses a variety of techniques to utilize the electricity system's existing capacity more efficiently. However, to date, only three countries have seriously considered implementing large load management programmes: Pakistan, Peru and Costa Rica. This paper describes a 1987-89 load control demonstration programme in Costa Rica, sponsored by the US Agency for International Development (AID), in which participating industries were able to reduce their peak demand by 14%. 相似文献
92.
Evaluation of the effect of a cover layer on radon exhalation from uranium mill tailings: transient radon flux analysis 总被引:1,自引:0,他引:1
An experimental study concerning the transport of 222Rn in uranium mill tailings (UMTs) and in the cover layer was launched in 1997 with the participation of the French uranium mining company (COGEMA). Evaluation of the cover layer's effectiveness in reducing 222Rn flux emanating from UMTs was one of its objectives. In the first phase, the 222Rn flux densities were measured regularly on a UMT layer. In the second phase, the UMT was covered with a one-meter layer of compacted material consisting of crushed waste rock derived from mining activities. Radon-222 flux was then measured at the surface of this cover layer. Observations were compared with radon flux calculated using TRACI, a model for vertical water and gas flow and radon transport. The results show that the calculations bear a fair resemblance to the observations in both cases. They also show that the effectiveness of the cover layer calculated with TRACI, using the thickness and textural properties of the cover material, is very close to the measured effectiveness. 相似文献
93.
94.
Anne-Leila Meistertzheim Isabelle Calvès Valérie Roussel Alain Van Wormhoudt Jean Laroche Sylvain Huchette Christine Paillard 《Marine Biology》2014,161(8):1883-1893
Increasing temperature of seawater is often associated with increased exposure incidence of disease in field and in aquaculture populations. Numerous episodic mass mortalities of the abalone Haliotis tuberculata have been observed along the northern Brittany coast of France caused by a complex interaction between the host, pathogen and environmental factors. Here, we evaluated the potential of high-resolution melting (HRM) analysis for mutation genotyping and development of genetic markers for resistance to vibriosis in the gastropod species H. tuberculata. Small amplicon assays were developed and revealed genetic polymorphism between surviving and susceptible abalone obtained after two successive infections of aquaculture families in controlled conditions. Together with specific COI haplotypes, we identified particular genotypes in nascent polypeptide-associated complex subunit alpha and ferritin genes linked to the susceptibility or resistance of abalone to vibriosis. Selection of genitors based on these genes may increase the proportion in offspring of resistant individuals of more than 76 %. Finally, HRM assays constitute a very efficient genotyping tool to validate the genetic markers on a representative number of individuals of wild populations and thus identify future resistant genitors for aquaculture or conservation purposes. 相似文献
95.
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97.
Ribolzi O Cuny J Sengsoulichanh P Mousquès C Soulileuth B Pierret A Huon S Sengtaheuanghoung O 《Environmental management》2011,47(2):291-302
Improving access to clean water has the potential to make a major contribution toward poverty reduction in rural communities
of Lao P.D.R. This study focuses on stream water quality along a Mekong basin tributary, the Houay Xon that flows within a
mountainous, mosaic land-use catchment of northern Lao P.D.R. To compare direct water quality measurements to the perception
of water quality within the riparian population, our survey included interviews of villagers. Water quality was found to vary
greatly depending on the location along the stream. Overall, it reflected the balance between the stream self-cleaning potential
and human pressure on the riparian zone: (i) high bacteria and suspended load levels occurred where livestock are left to
free-range within the riparian zone; (ii) very low oxygen content and high bacteriological contamination prevailed downstream
from villages; (iii) high concentrations of bacteria were consistently observed along urbanized banks; (iv) low oxygen content
were associated with the discharge of organic-rich wastewater from a small industrial plant; (v) very high suspended load
and bacteria levels occurred during flood events due to soil erosion from steep cultivated hill slopes. Besides these human
induced pollutions we also noted spontaneous enrichments in metals in wetland areas fed by dysoxic groundwater. These biophysical
measurements were in agreement with the opinions expressed by the majority of the interviewees who reported poor and decreasing
water quality in the Houay Xon catchment. Based on our survey, we propose recommendations to improve or maintain stream water
quality in the uplands of northern Lao P.D.R. 相似文献
98.
Sugimoto JD Labrique AB Ahmad S Rashid M Shamim AA Ullah B Klemm RD Christian P West KP 《Disasters》2011,35(2):329-345
The epidemiology of tornado-related disasters in the developing world is poorly understood. An August 2005 post-tornado cohort study in rural Bangladesh identified elevated levels of death and injury among the elderly (≥ 60 years of age) (adjusted odds ratio (AOR) = 8.9 (95 per cent confidence interval (CI): 3.9-20.2) and AOR = 1.6 (95 per cent CI: 1.4-1.8), respectively), as compared to 15-24 year-olds, and among those outdoors versus indoors during the tornado (AOR = 10.4 (95 per cent CI: 5.5-19.9) and AOR = 6.6 (95 per cent CI: 5.8-7.5), respectively). Females were 1.24 times (95 per cent CI: 1.15-1.33) more likely to be injured than males. Elevated risk of injury was significantly associated with structural damage to the house and tin construction materials. Seeking treatment was protective against death among the injured, odds ratio = 0.08 (95 per cent CI: 0.03-0.21). Further research is needed to develop injury prevention strategies and to address disparities in risk between age groups and between men and women. 相似文献
99.
St��phane Descloux Vincent Chanudet Herv�� Poilv�� Alain Gr��goire 《Environmental monitoring and assessment》2011,173(1-4):723-741
An assessment of the organic carbon stock present in living or dead vegetation and in the soil on the 450 km2 of the future Nam Theun 2 hydroelectric reservoir in Lao People??s Democratic Republic was made. Nine land cover types were defined on the studied area: dense, medium, light, degraded, and riparian forests; agricultural soil; swamps; water; and others (roads, construction sites, and so on). Their geographical distribution was assessed by remote sensing using two 2008 SPOT 5 images. The area is mainly covered by dense and light forests (59%), while agricultural soil and swamps account for 11% and 2%, respectively. For each of these cover types, except water, organic carbon density was measured in the five pools defined by the Intergovernmental Panel on Climate Change: aboveground biomass, litter, deadwood, belowground biomass, and soil organic carbon. The area-weighted mean carbon densities for these pools were estimated at 45.4, 2.0, 2.2, 3.4, and 62.2 tC/ha, respectively, i.e., a total of about 115 ± 15 tC/ha for a soil thickness of 30 cm, corresponding to a total flooded organic carbon stock of 5.1 ± 0.7 MtC. This value is much lower than the carbon density for some South American reservoirs for example where total organic carbon stocks range from 251 to 326 tC/ha. It can be mainly explained by (1) the higher biomass density of South American tropical primary rainforest than of forests in this study and (2) the high proportion of areas with low carbon density, such as agricultural or slash-and-burn zones, in the studied area. 相似文献
100.
Alain Dejean Céline Leroy Bruno Corbara Régis Céréghino Olivier Roux Bruno Hérault Vivien Rossi Roberto J. Guerrero Jacques H. C. Delabie Jérôme Orivel Raphaël Boulay 《Die Naturwissenschaften》2010,97(10):925-934
Myrmecophytes offer plant-ants a nesting place in exchange for protection from their enemies, particularly defoliators. These obligate ant–plant mutualisms are common model systems for studying factors that allow horizontally transmitted mutualisms to persist since parasites of ant–myrmecophyte mutualisms exploit the rewards provided by host plants whilst providing no protection in return. In pioneer formations in French Guiana, Azteca alfari and Azteca ovaticeps are known to be mutualists of myrmecophytic Cecropia (Cecropia ants). Here, we show that Azteca andreae, whose colonies build carton nests on myrmecophytic Cecropia, is not a parasite of Azteca–Cecropia mutualisms nor is it a temporary social parasite of A. alfari; it is, however, a temporary social parasite of A. ovaticeps. Contrarily to the two mutualistic Azteca species that are only occasional predators feeding mostly on hemipteran honeydew and food bodies provided by the host trees, A. andreae workers, which also attend hemipterans, do not exploit the food bodies. Rather, they employ an effective hunting technique where the leaf margins are fringed with ambushing workers, waiting for insects to alight. As a result, the host trees’ fitness is not affected as A. andreae colonies protect their foliage better than do mutualistic Azteca species resulting in greater fruit production. Yet, contrarily to mutualistic Azteca, when host tree development does not keep pace with colony growth, A. andreae workers forage on surrounding plants; the colonies can even move to a non-Cecropia tree. 相似文献