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811.
812.
Kathleen J. Miller 《Journal of the American Water Resources Association》2005,41(2):257-265
ABSTRACT: A series of gravel terraces support a shallow aquifer that is the sole source of drinking water for three public water supplies and more than 400 private wells on the Greenfields Bench in west‐central Montana. Farming practices on the Greenfields Bench include irrigation of malting barley and the yearly application of herbicides for the control of weeds. The most commonly used herbicide (imazamethabenz‐methyl, U.S. trade name Assert®) has been found in the ground water on the Greenfields Bench. An experiment was conducted in 2000 and 2001 to characterize the transport of Assert and its acid metabolite to ground water under three irrigation methods: flood, wheel line sprinkler, and center pivot sprinkler. Results show that Assert concentrations in ground water are controlled by hydraulic loading rates of each irrigation method, Assert persistence in soil, hydraulic characteristics of the aquifer, and adsorption/desorption of Assert onto clay particles and organic matter. 相似文献
813.
814.
Ronald L. Ritschard Karen Tsao 《Journal of the American Water Resources Association》1980,16(2):340-347
ABSTRACT: Growers in California used several energy and water conservation strategies in response to the drought conditions of 1976 and 1977. The strategies included an increased use of ground water, in creased irrigation efficiencies, and shifts in cropping patterns. Drought-related losses to irrigated agriculture were minimized as a result of these modifications. Some future problems may have been created, however, by obtaining the needed water supplies for 1976–77. These problems include the effects of extensive water pumping on ground water reservoirs and ground subsidence. In addition, reduced water application by less frequent irrigation and changes in irrigation methods may affect the total salt balance for future years. Several conservation strategies that have some potential application in California were identified as: maintaining and augmenting surface water supply, increasing power use efficiencies, and improving irrigation efficiencies. Electricity savings associated with water conservation have been estimated as high as 25 percent. Specific near term actions suggested for facilitating conservation included: an expanded irrigation management system, efficient water deliveries, and a continued effort on the part of the individual growers to use resources during periods of normal rainfall as they were used under drought conditions. 相似文献
815.
Mark A. Boster William E. Martin 《Journal of the American Water Resources Association》1979,15(1):206-219
ABSTRACT: The importation of water into an existing irrigated agricultural area raises many questions about farm profitability and suggests many adjustment alternatives open to farmers. In particular, how will farmers respond to a new additional water source of differing cost, availability, and quality? Mathematical programming models of representative irrigated farms in Pinal County, Arizona, were developed to project agricultural adjustments to new water from the Central Arizona Project now under construction. The techniques developed have broad application to similar water resource projects involving the conjunctive use of multiple water sources of differing qualities. Regional agricultural activities are described by defining and modeling multiple representative farms which account for economies due to size and different water sources of differing price and quality. Various management schemes can be evaluated by properly selected representative farm models. 相似文献
816.
Kenneth O. Kauffman 《Journal of the American Water Resources Association》1979,15(2):387-395
ABSTRACT: In many of the limited water resource areas of the western United States most water supplies have been put to beneficial uses. Energy, a fast expanding high-priority water use, is making challenging demands for these limited supplies. Can water supplies be stretched, supplemented, or redirected so that present uses can be maintained and energy water needs satisfied? The Bureau of Reclamation is investigating innovative methods of water management, reregulation, and use to meet these demands. Related programs under study include potentials for: development of additional hydroelectric power, installation of low-head turbines in western water courses, utilization of pumped storage and underground storage, use of geo-thermal heat, extension of water supplies through more efficient irrigation systems and practices, and weather modification. 相似文献
817.
L. Icerman 《Journal of the American Water Resources Association》1978,14(3):651-662
ABSTRACT: Factual inputs which may be useful for completing first-order assessments to aid decision-making on the allocation of scarce water resources are compiled. Water needs of major manufacturing industry groups and of minerals industries show wide variations in several measures of water use intensity. The chemicals and allied products and primary metals industries dominate the total water intake and consumptive water use by manufacturing industries. Consumptive use per employee for the petroleum and coal products industry group is nearly 2.5 times higher than that for any other industry group. Estimates of the water requirements per unit energy output for energy-processing systems vary by as much as an order of magnitude. Agricultural water use is larger than that of any other industry but water use for irrigation is not expected to increase significantly by the year 2020. In California, the production of crop calories and proteins per unit of irrigation water applied may vary by more than an order of magnitude. Crops which offer larger monetary returns per acre are irrigated most frequently. 相似文献
818.
ABSTRACT: Irrigated agriculture is one of the most important water-use sectors in terms of total water diversion and consumptive use. For at least the last 25 years, improving irrigation efficiency has been a widely advocated and accepted goal. This paper uses a sample of 16 Bureau of Reclamation irrigation projects to examine the pattern of average irrigation efficiency and change in efficiency over time. In general, the highest average efficiencies are found in the arid Southwest while the lowest are found in the semi-arid to sub-humid Great Plains region. Over the 22-year period of analysis, there has been no observable trend toward improvement in efficiency at any of the projects. 相似文献
819.
Marshall Flug Robert H. Montgomeiy 《Journal of the American Water Resources Association》1988,24(5):1073-1081
ABSTRACT: A basic problem in the management of rivers has been how to balance the tradeoffs between instream and out-of-stream uses. Traditionally, the problem has been addressed by optimizing the economic benefits of flow diversions and regulated releases with instream uses as a flow constraint. An alternative method is to model the effect different river flows have on various recreational uses (e.g., boating, fishing) and then use the results as an additional function or piece of information to determine river project operations and benefits. A methodology that is based on multiobjective decision theory and that relates instream recreational preferences to river flow is proposed. The methodology consists of determining, standardizing, and combining recreational benefit functions, and incorporating potential sources of uncertainty into an estimate of total instream benefits. Thus different types of flow patterns, resulting from reservoir regulation (out-of-stream water uses), can be analyzed to determine their potential instream impact. The methodology is applied to the New River Gorge, West Virginia, which has been designated as a National River. 相似文献
820.
J. R. Steadman C. R. Maier H. F. Schwartz E. D. Kerr 《Journal of the American Water Resources Association》1975,11(4):796-804
ABSTRACT: Systematic sampling of waterways and irrigation runoff from agricultural lands in the North Platte Project of Nebraska in July and August of 1972–1974 demonstrated that phytopathogenic organisms were disseminated. The organisms monitored included the bean common blight bacterium Xanthomonas phaseoli, the bean white mold fungus Whetzelinia sclerotiorum and various nematodes. Although many types of nematodes often were recovered from irrigation water, Heterodera sp. cysts which cause significant disease problems in the valley were found infrequently. Patterns of movement of the bacterial and fungal organisms were correlated with previous or current season infection of bean plants. The short-term survival of X. phaseoli in sterile deionized water may explain the detection of this organism only in runoff or ditches receiving runoff from common blight infected bean fields. Sclerotial bodies of W. sclerotiorum remained viable for at least 10–21 days in flowing water and were found throughout the irrigation waterways. Irrigation of beans with contaminated water can result in both common blight and white mold diseases. Dissemination of phytopathogenic organisms in irrigation reuse systems as well as agricultural land runoff should be considered in irrigation planning and system design. 相似文献