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251.
ABSTRACT: At a time when productive water resources research is essential to protecting the quality of and wisely using our limited water resources, pervasive trends toward consumerism, fiscal restraint, centralized management, and using research for other social objectives threaten research productivity. The research prioritization and management structure that these trends have created was examined in the microcosm of its application at the Utah Water Research Laboratory. The result indicated that ephemeral prioritization and the failure of research users to target researchers to their own particular needs is diluting productivity. Incremental research prioritization and greater use of advisory councils in facilitating user-researcher interaction are suggested as corrective approaches, but the only firm conclusion at this point in time must be that empirical studies of the performance of alternatives in research management structure are solely needed. 相似文献
252.
Jay R. Stauffer 《Journal of the American Water Resources Association》1981,17(3):504-507
The bluespotted sunfish, Enneacanthus gloriosus (Holbrook), had a final temperature preferendum of 31.5 C. Fish acclimated to 30 C avoided 36 C. The analysis of acute temperature preference data and the relationship between final temperature preferendum and upper avoidance temperatures are discussed. 相似文献
253.
Jay?K.?Goldberg Alisa?K.?Wallace Stacey?L.?WeissEmail author 《Die Naturwissenschaften》2017,104(9-10):81
Sex pheromones can perform a variety of functions ranging from revealing the location of suitable mates to being honest signals of mate quality, and they are used in the mate selection process by many species of reptile. In this study, we determined whether the skin lipids of female striped plateau lizards (Sceloporus virgatus) can predict the reproductive quality of females, thereby having the potential to serve as pheromones. Using gas chromatography/mass spectrometry, we identified 17 compounds present in skin lipids of female lizards. Using principal component analysis to compare the skin lipid profile of receptive and non-receptive females, we determined that an uncharacterized compound may allow for chemical identification of receptive mates. We also compared extracted principal components to measures of female fitness and reproductive qualities and found that the level of two 18 carbon fatty acids present in a female’s skin lipids may indicate her clutch size. Finally, we compared the information content of the skin lipids to that of female-specific color ornaments to assess whether chemical and visual cues transmit different information or not. We found that the chroma of a female’s orange throat patch is also related to her clutch size, suggesting that chemical signals may reinforce the information communicated by visual ornamentation in this species which would support the “backup signals” hypothesis for multiple signals. 相似文献
254.
Jay N. Meegoda Wiwat Kamolpornwijit 《Frontiers of Environmental Science & Engineering in China》2011,5(2):159-166
As species we humans generate excessive amounts of waste and hence for sustainability we should explore innovative ways to
recover them. The primary objective of this study is to demonstrate an efficient and optimum way to recover chromium and iron
from chromite ore processing residues (COPR) for the production of chrome steel and stainless steel. In Hudson County, New
Jersey, there are more than two million tons of leftover COPR. Part of COPR was used as fill materials for construction sites,
which spread the problem to a larger area. With high solubility along with their toxicity leached chromate from COPR is threatening
the environment as well as human health. In this research, COPR was thermally treated to recover iron with chromium by applying
techniques used in steel manufacturing. An extensive experimental program was performed using a Thermo-Gravimetric Analyzer
(TGA) and bench scale tests to thermally treat the processed chromium contaminated soils with carbon and sand at varying temperatures
and under reducing environment. The optimum chemical composition of COPR and additives to be used in the melts were evaluated
based upon the thermodynamic properties of the mixture to ensure good phase separation, least amounts of iron and chromium
oxides in the slag and minimum variability of final product (steel or iron with chromium). The impact of other oxides on the
steel making process was evaluated to minimize the adverse impact on the process. The research demonstrated the feasibility
of recovering a valuable construction material (chrome steel) from a waste (COPR). 相似文献
255.
Optimal hardwood tree planting and forest reclamation policy on reclaimed surface mine lands in the Appalachian coal region 总被引:4,自引:0,他引:4
We study the optimal hardwood tree planting decision on reclaimed surface coal mines in the Appalachian region using a mine operator-focused, expected cost model that recognizes costs of preparing the site for tree planting, unit costs of planting seedlings, and opportunity costs of reforestation treatments and the performance bond. We also consider the possibility of failed initial attempts by incorporating the probability of reforestation success, based on empirical seedling ,survival rates and regulated tree survival standards, as well as fixed and unit costs of returning for additional planting. Optimal planting levels from 319 to 780 trees per acre and expected costs from $1049 to $2338 were found using simulations over a range of unit planting costs, fixed costs of replanting, tree survival standards, and interest rates. Further simulations compared optimal planting across un-weathered gray sandstone and weathered brown sandstone substrate materials, finding gray sandstone to be associated with lower expected costs. We conclude that optimal planting density and expected reforestation cost are sensitive to economic parameters, regulations, and planting substrate materials; and those policies influencing these factors may have substantial impact on reforestation outcomes and the choice of post-mining land use by mine operators. Our study provides a framework for understanding forest reclamation decisions that incorporates incentives faced by the mine operators who develop and implement the plans for mine reclamation, including forestry. 相似文献