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981.
This paper describes three relatively recent innovations in the Dutch agri-environment programme which have helped nature management to be contiguous with natural features allowing the landscape to be managed whole rather than piecemeal—and thus generate higher quality and greater scope in environmental management. The first two, joint submissions by neighbouring farmers and payments related to the level of environmental output delivered, are scheme innovations. The third, Environmental Co-operatives (EC)—clubs of neighbouring farmers that inter alia co-ordinate and help manage the scheme innovations—is an institutional innovation. None has an equivalent in the UK. Evidence from interviews with farmer and non-farmer members, policy makers, academics and other interested parties show the role EC play in overcoming some of the postulated problems of the two scheme innovations. Not all the problems have been overcome, and cost-benefit analyses have not been conducted, nevertheless there is sufficient evidence to suggest that these innovations have benefited all actors involved: farmers, the government, the environment and the rural economy. Analysis of UK agri-environment policy using actor network theory (ANT) suggests the UK government will need to show similar levels of trust in and commitment to the farming community before these innovations could be introduced in the UK. 相似文献
982.
Joris Mergaert Kurt Ruffieux Christophe Bourban Virginie Storms Wim Wagemans Erich Wintermantel Jean Swings 《Journal of Polymers and the Environment》2000,8(1):17-27
A simple and rapid in vitro test was designed for the assessment of the biodegradation of polyester-based plastics by selected biodegrading bacterial strains. Variovorax paradoxus LMG 16137 was used for the degradation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Acidovorax avenae subsp. avenae LMG 17238 fo the synthetic-based polyesters poly(-caprolactone) (PCL), poly(butylene succinate-co-butylene adipate), and a starch-PCL blend. Degradation by the bacteria was studied in liquid medium with the plastics (films, granules, and injection-molded test bars) as sole sources of carbon. Degradation was followed through gravimetry, growth of the culture, and tensile testing. The effects of incubation time, inoculum density, aeration, incubation temperature, and pH of the medium on the mass loss were investigated and conditions optimized. The test allowed to obtain reproducible results on the mass loss of plastic samples in less than 3 weeks and yielded excellent partially degraded samples for further analysis. 相似文献
983.
984.
985.
986.
Kurt Beth 《Die Naturwissenschaften》1956,43(13):307-308
987.
Dr. William T. Pecora 《Journal of the American Water Resources Association》1971,7(5):1105-1106
Ten years ago in the United States, per capita water use for all purposes was about 1500 gallons a day. By the year 2000, our population will have grown from 200 to 350 million, and each person, in effect, will be using 2500 gallons per day, This could result in our using as much as 75 percent of the total average runoff from US. Rivers
Perhaps as much as 40,000 cubic miles of saline water are stored in rocks at various depths underlying extensive areas of the United States, according to the U.S. Geological Survey. This water, once considered of no value and even a nuisance, now represents a vast potential source of water, either as replacement of fresh water for certain uses or as the raw material for desalting techniques which have been studied intensively in recent years. Desalination creates new water in the sense that saline water, never before used, becomes part of our water economy. 相似文献
Perhaps as much as 40,000 cubic miles of saline water are stored in rocks at various depths underlying extensive areas of the United States, according to the U.S. Geological Survey. This water, once considered of no value and even a nuisance, now represents a vast potential source of water, either as replacement of fresh water for certain uses or as the raw material for desalting techniques which have been studied intensively in recent years. Desalination creates new water in the sense that saline water, never before used, becomes part of our water economy. 相似文献
988.
Inhibition of photosynthesis by ultraviolet radiation as a function of dose and dosage rate: Results for a marine diatom 总被引:8,自引:0,他引:8
The effects of ultraviolet radiation on phytoplankton are usually described as a function of dose (J m–2, weighted appropriately). Experiments conducted in 1988 and 1989 on a marine diatom,Thalassiosira pseudonana (Clone 3H), demonstrate that during lightlimited photosynthesis in visible radiation, the inhibition of photosynthesis by supplemental ultraviolet radiation (principally UV-B: 280 to 320 nm) is a function of irradiance (W m–2) as well as of dose: for equal doses of UV-B, a relatively short exposure to high UV-B irradiance is more damaging to photosynthesis than a longer exposure to lower irradiance. In fact, photoinhibition by UV-B is well described as a monotonic, nonlinear function of irradiance for time scales of 0.5 to 4 h. A nitrate-limited culture was about nine times more sensitive to UV-B than was a nutrient-replete culture, but the kinetics of photoinhibition were similar. These results have some bearing on efforts to describe the effects of ultraviolet radiation on marine primary productivity. Action spectra of photoinhibition by UV can be constructed, but they should only be used to describe photoinhibition for specified time scales. Vertical profiles of relative photoinhibition must be interpreted cautiously because photoinhibition by UV-B is likely to be a function of incubation time and results must therefore be interpreted in the context of vertical mixing. 相似文献
989.
990.