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511.
Earlier papers indicated that the first incident of green discoloration in oysters (Crassostrea gigas) and the mass mortality observed in 1986 along the Taiwan Erhjin Chi coastal area were caused by the higher contents of total copper and copper species (mainly bioavailable and free ion) in sea water. the copper in sea water would be sorbed by suspended matter and transferred to sediments, and the copper in the sediments would also be desorbed to sea water. Processes of copper adsorption and desorption are the major factors influencing the contents of total copper and copper species in sea water and sediments. in this study, the Erhjin Chi sediments were mixed with sea water by a shaker technique. When the mixture was shaken for one hour, analogous to tidal mixing in estuaries, only copper desorption from sediments was observed. If the shaking time is increased for more than 3 hours, the copper released from the sediments was resorbed to the remaining solid phases. the higher the contents of mud (91.71%) and total copper (701 mg kg-1) in sediments, the higher the copper desorption rate (1.86 ppm hr-1) and copper adsorption rate (0.50 ppm hr-1) were observed. in sediments containing lower mud (0.80%) and lower copper (43.5 mg kg-1), the copper desorption and adsorption rates were 0.83 ppm hr-1 and 0.22 ppm hr-1, respectively. the interactions among the total copper and copper species in sea water and sediments, chemical and ecological parameters, and copper bioaccumulation in oysters in the Erhjin Chi estuarine and coastal area are also discussed. 相似文献
512.
岸滩侵蚀的环境工程观念 总被引:3,自引:0,他引:3
本文从环境工程的角度讨论了岸滩侵蚀问题中建立分析模型的基本框架.讨论了岸滩岩土介质在风浪潮作用下,根据不同的侵蚀准则所建立的岸滩沉积物在近海迁移和传输的模型.得出了岸滩的侵蚀、演变过程由三相组成的结论,第一相是与饱和多孔介质经受动力载荷变形和损伤相联系的固态相;第二相是关于介质侵蚀和剥离的流-固态混合相;第三相是流动和沉积物运输的流体相.从分析讨论还可以看出,岸滩侵蚀演化的模拟分析可在岸滩介质的动力固结、悬浮介质扩散漂移及海浪流体动力学理论相互交叉的基础上,针对海岸环境工程问题中的观念和现象来建模并完成.研究表明,在分析海滩侵蚀和海岸演化过程的机理时,采用海洋环境工程学中的相关方法可以得到更符合实际状况的结果.用损伤力学方法建摸研究岸滩介质的侵蚀和沙化过程,可以将海岸沉积物的迁移速率描述为海床面上的等效摩擦剪应力、损伤状态、侵蚀参数及介质的孔隙冲蚀率的函数.在岸滩侵蚀和演化机理研究中将海岸沉积物的纵向迁移和横向迁移理论相结合的模型有一定的优越性,这为岸滩侵蚀与海岸演变提供了定量的分析方法. 相似文献
513.
514.
Multivariate analysis of variance, canonical correlation and canonical discriminate analysis were performed on environmental data collected from the Kuwaiti intertidal zone to determine the statistical relationships between the sediment, chemical, biological, spatial and temporal variables. The quantitative analysis showed that the sediment type was the paramount factor influencing the distribution and composition of the intertidal benthic fauna. The muddy, sandy and rocky shores support three distinct faunal communities. The seasonal variation in the benthic fauna community was not statistically significant but variation in biological data due to differences in transect location and tidal level were significant. This spatial variation has been attributed to differences in sediment and substrate types. The physico-chemical parameters were found to correlate positively with the mud content of the sediments but were unimportant in the overall composition of the intertidal fauna. This paper complements the results reported in Al Bakriet al. (1997–Part I) in establishing a valuable benchmark for assessing environmental impacts and for developing sustainable coastal zone management in Kuwait. The integrated approach outlined here could be adopted to develop a sound basis for the protection and management of coastal environments and resources in similar areas. 相似文献
515.
516.
Jack C. Nelson Donald G. Rauschuber Lial F. Tischler 《Journal of the American Water Resources Association》1973,9(6):1249-1257
ABSTRACT. The Texas Water Development Board, the principal water resource planning agency of the State, has been conducting extensive estuarine data collection activities and associated research to determine the required quantity and quality of fresh water inflows necessary to maintain various environmental conditions in Texas estuaries to preserve the estuarine ecosystems. These activities are a consequence of a statutory directive to the Board to make provisions in its State Water Plan for the effects of upstream water resource development on the associated estuaries. This paper reports on the results of the first phase of an extensive estuarine research project. The objectives of the research project are to (1) define the interrelationships between estuarine ecosystems and fresh water and nutrient inflows, and (2) develop and test quantitative simulation techniques which describe these relationships. In order to accomplish the first objective, physical and chemical water quality data and biological data on the estuarine ecosystems are being collected, compiled and analyzed. The second objective is being satisfied by the development of hydrodynamic and ecologic simulation models of the estuarine environment. 相似文献
517.
为了研究桉树人工林是否会对海洋初级生产者产生影响,实验选取了桉树及4种滨海植物(木麻黄、台湾相思、秋茄和白骨壤),对比5种植物叶片水浸提液对纤细角毛藻生长的影响。结果显示,桉树对纤细角毛藻生长的影响最大,低浓度的叶片水浸提液(5 m L/L)表现出很强的抑藻作用;木麻黄、台湾相思和秋茄对纤细角毛藻生长的影响次之,低浓度的叶片水浸提液(5 m L/L)表现出较弱的抑藻作用,15 m L/L时,对藻的抑制作用较强;白骨壤对纤细角毛藻生长的影响最弱,25 m L/L时,表现出对藻有较弱的抑制作用。实验结果表明,桉树比其他常见的滨海植物对海洋微藻具有更强的化感作用,在沿海地区大面积种植桉树人工林会对海洋初级生产者产生潜在的影响。 相似文献
518.
Hydrogeomorphic Reference Condition and Its Relationship with Macroinvertebrate Assemblages in Southeastern U.S. Sand Hills Streams
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Stephen A. Sefick Ely Kosnicki Michael H. Paller Jack W. Feminella 《Journal of the American Water Resources Association》2018,54(4):914-933
Defining stream reference conditions is integral to providing benchmarks to ecological perturbation. We quantified channel geometry, hydrologic and environmental variables, and macroinvertebrates in 62 low‐gradient, SE United States (U.S.) Sand Hills (Level IV ecoregion) sand‐bed streams. To identify hydrogeomorphic reference condition (HGM), we clustered channel geometry deviation from expectations given watershed area (Aws), resulting in two HGM groups discriminated by area at the top of bank (Atob) residuals <0.6 m2 and >0.6 m2 predicted to be HGM reference/nonreference streams, respectively. Two independent partial least squares discriminate analyses used (1) hydrologic/environmental variables and (2) macroinvertebrate mean trait values (mT) on 10 reference/nonreference stream pairs of similar Aws for classification validation. Nonreference streams had flashier hydrographs and altered flow magnitudes, lower organic matter, coarser substrate, higher pH/specific conductivity compared with reference streams. Macroinvertebrate assemblages corresponded to HGM groupings, with mT indicative of multivoltinism, collector‐gatherer functional feeding groups, fast current‐preference taxa, and lower Ephemeroptera, Plecoptera, and Trichoptera richness and biotic integrity in nonreference streams. HGM classifications in Sand Hills, sand‐bed streams were determined from channel geometry. This easily implemented classification is indicative of contemporary hydrologic disturbance resulting in contrasting macroinvertebrate assemblages. 相似文献
519.
A Framework for Incorporating the Impact of Water Quality on Water Supply Stress: An Example from Louisiana,USA
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David M. Borrok Jian Chen Hisham Eldardiry Emad Habib 《Journal of the American Water Resources Association》2018,54(1):134-147
Water of poor quality can directly impact the budget of water available for key user groups. Despite this importance, methods for quantifying the impact of water quality on water availability remain elusive. Here, we develop a new framework for incorporating the impact of water quality on water supply by modifying the Water Supply Stress Index (WaSSI). We demonstrate the usefulness of the framework by investigating the impact of high salinity waters on the availability of irrigation water for agriculture in Louisiana. The WaSSI was deconstructed into sectoral components such that the total available water supply could be reduced for a particular demand sector (agricultural irrigation in this example) based on available water quality information. The results for Louisiana highlight substantial impacts on water supply stress for farmers attributable to the landward encroachment of saline surface water and groundwater near the coast. Areas of high salinity near the coast also increased the competition for freshwater resources among the industrial, municipal, and agricultural demand sectors in the vicinities of the municipal areas of Lake Charles, Lafayette, and Baton Rouge, Louisiana. The framework developed here is easily adaptable for other water quality concerns and for other demand sectors, and as such can serve as a useful tool for water managers. 相似文献
520.