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Bacterial diversity in selenium reduction of agricultural drainage water amended with rice straw 总被引:1,自引:0,他引:1
Siddique T Okeke BC Zhang Y Arshad M Han SK Frankenberger WT 《Journal of environmental quality》2005,34(1):217-226
Bacterial reduction of the Se oxyanions selenate [Se(VI)] and selenite [Se(IV)] to elemental selenium [Se0] is an important biological process in removing Se from drainage water. This study was conducted to characterize the molecular diversity of bacterial populations involved in Se reduction of drainage water amended with rice (Oryza sativa L.) straw and also to monitor the bacterial community shifts during the course of the study. Selenate was removed in the drainage water by the bacteria 5 to 6 d after addition of rice straw. Six Se(VI)- and 32 Se(IV)-reducing bacteria were isolated from rice straw containing sterilized drainage water. Three Se(VI)- and two Se(IV)-reducing bacteria were also isolated from the drainage water. Identification of Se(VI)- and Se(IV)-reducing bacteria by 16S rDNA sequence analysis showed a broad phylogenetic diversity in Se-reducing assemblages. Three major phyla (Proteobacteria, Actinobacteria, and Firmicutes) of bacterial domain with numerous classes, orders, and families constituted the Se-reducing bacterial community. We documented changes in the composition of bacterial assemblages in the drainage water amended with rice straw using polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) of 16S rDNA. The Shannon-Weaver index (H') revealed higher bacterial diversity at Day 6 in the sterilized and Day 4 in the non-sterilized drainage water amended with rice straw. The results of this study suggest that rice straw, a good source of carbon and energy, harbors a wide range of bacteria useful in Se reduction and may be used in removing Se from drainage water. 相似文献
773.
In recent years, as part of its neoliberal development paradigm, the Government of the Philippines has engaged in efforts to encourage extraction of the nation's mineral resources. The Philippines is also a country where decentralization has devolved substantial powers to local governments. Concern over potentially adverse environmental effects has led to opposition to mining by some local governments in the Philippines. This opposition has led to the withholding of consent to mining projects by local governments and, in some cases, the implementation of moratoriums banning mining. Central to this opposition have been the activities of civil society groups, and their collaboration with local governments. This collaboration has involved the drafting of legislation prohibiting mining and support of candidates for office who are opposed to mining. Collectively, Filipino local governments and civil society groups are examples of the concept of governance, a dispersed process wherein society manages itself for the betterment of all its members. For mining companies seeking to implement projects, it is no longer sufficient to have the consent of the national Government — that of local governance forces must also be considered. 相似文献
774.
Mining of construction aggregate is often unwelcome near communities because of its disamenities or because it can destroy prime farmland and displace other desirable land uses. Such conflicts have led to prohibitions against mining near cities or on high-value farmland, causing these operations to be relocated to more distant locations. The cost of this relocation may go unnoticed if they are indirect, diffused and rise gradually over time, but they may be significant due to the high transportation cost of moving these materials long distances. 相似文献
775.
William G. Cale 《Ecological modelling》1979,7(2):107-123
A methodology for characterizing a complex ecological process — primary production — using linear mathematics is presented. The resulting model uses a limiting factor approach for calculating realized productivity based on prevailing conditions of moisture, temperature, incident radiation and available nutrients. Processes such as leaching and respiration are keyed to environmental variables. Simulation values are presented and compared to measured data. 相似文献
776.
William A. Vogely 《Resources Policy》1978,4(3):178-180
Nonfuels minerals policy in the USA flows from the differential and unique reactions of these industries to general economic policies in the areas of taxation, land use, environment, and international trade. To search for nonfuels minerals policy as direct statements by the US government on nonfuels minerals is futile. Nevertheless, the industries are unique in many characteristics, and the application of these general policies to the minerals industries creates unique situations. This uniqueness has been recognized by a virtually constant policy review over the past 10 years. The current effort is just beginning, and to prejudge now the outcome of this discussion is premature. However, it is not premature to argue that because of the uniqueness of these industries, it may be expected that their problems will be receiving public attention for many years to come. 相似文献
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William A. Jury Gideon Sinai Lewis H. Stolzy 《Journal of the American Water Resources Association》1979,15(5):1444-1458
ABSTRACT: Electric generation facility water requirement will increase substantially in the future in the Western United States because new power plants are to be constructed at inland sites rather than on the coast. At the inland locations, power plants will have to compete with agriculture and public users for fresh water supplies, and will be constrained by environmental legislation to dispose of cooling waste water in lined evaporation ponds. The various options for power plant cooling are analyzed in respect to cost, water consumption, and environmental hazard, and also in respect to their compatibility with existing state and federal regulations. Several proposals for balancing the water requirements of various users in water-scarce areas are reviewed and criticized. 相似文献