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131.
Julia Hertin Marcus Wagner Daniel Tyteca 《Journal of Environmental Planning and Management》2008,51(2):259-283
Based on the analysis of a large dataset on the environmental performance of European companies in five industrial sectors, this paper examines the question of whether the presence of an environmental management system (EMS) has a positive impact on the eco-efficiency of companies. It begins with a review of evidence about the link between EMS and environmental performance in business organisations, finding that, despite much research, there is still little quantitative evidence. The second part of the paper uses three independent statistical methods (simple correlations, Jaggi-Freedman indices and a ‘trend differences’ approach) to assess whether companies and production sites with EMS perform better than those without and whether performance improves after an EMS has been introduced. The paper shows that there is currently no evidence that EMS have a consistent and significant positive impact on environmental performance. Policy action based on the simple assumption that companies with an EMS perform better than those without therefore seems inappropriate. 相似文献
132.
Schröder W Hornsmann I Pesch R Schmidt G Markert B Fränzle S Wünschmann S Heidenreich H 《Environmental monitoring and assessment》2007,133(1-3):495-505
The study was conducted to test the hypothesis that the regional variability of nitrogen (N) and metal accumulations in terrestrial ecosystems are due to historical and recent ways of landuse. To this end, two regions of Central Europe were selected for investigation: the Weser-Ems Region (WER) and the Euro Region Nissa (ERN). They were assumed to have land use-specific accumulation profiles. Thus, the metal and N accumulations in both regions were examined by means of geostatistically based comparative moss analysis. The sampling and chemical analysis of mosses were conducted in accordance with the convenient guidelines and methods, respectively. The spatial representativity of the sampling sites was computed by means of a land classification which was calculated for Europe by means of classification trees and GIS-techniques. The differences of deposition loads were tested for statistical significance with regard to time and space. The measurement values corroborated the decline of metal accumulation observed since the beginning of the European Metals in Mosses Surveys in 1990. The metal loads of the mosses in the ERN exceeded those in the WER significantly. The opposite holds true for the N concentrations: those in the WER were significantly higher than those in the ERN. The reduction of emissions from power plants, factories and houses was strongly correlated with the decline of deposition and bioaccumulation of metals. As proved by the European Metals in Mosses Surveys, this tendency is due to successful environmental policies. But no such success could be verified by monitoring the accumulation of N in mosses. 相似文献
133.
Copepod resting eggs are abundant in the seabed of many bays and estuaries where they provide a potential source of recruits
for growth of planktonic populations. In the northeastern Gulf of Mexico the copepod Centropages hamatus (Lillejeborg) occurs in the water column only during the late fall, winter and early spring. The species produces subitaneous
and diapause eggs, and both egg types have been found in the seabed. We determined the longevity of these two egg types to
ascertain their potential for contributing to the growth of the planktonic population and for sustaining a persistent egg
bank. Eggs were collected from females and incubated in the laboratory under temperature and oxygen conditions chosen to simulate
field conditions. The diapause eggs were also exposed to sulfide. The total hatching success of subitaneous eggs in two experiments
declined from highs of 78 and 97% to zero after 60 and 90 d of exposure to anoxia. The total hatching success of diapause
eggs that were exposed to anoxia for 90 d however was typically greater than 80%. Some diapause eggs hatched after being incubated
under anoxia for 437 d. Diapause eggs survived longer at ambient field temperatures when incubated under anoxia (437 d) compared
to normoxia (118 d). Exposure to sulfide did not result in greater mortality of diapause eggs compared to anoxia alone. Diapause
eggs that were incubated at ambient field temperatures did not hatch when exposed to normoxia until the temperature dropped
to <20 °C. The results of this study suggest that C.␣hamatus sustain a short-term reserve of subitaneous eggs in the seabed that provides recruits for the current year's population.
The greater longevity of diapause eggs suggests that they sustain the seasonal reappearance of the species year after year
in the northeastern Gulf of Mexico. However, the contribution of diapause eggs of C. hamatus from the Gulf of Mexico to a persistent egg bank is questionable since hatching ceased after 437 d.
Received: 30 July 1997 / Accepted: 18 January 1998 相似文献
134.
Rainer Haas Alfred Krippendorf Torsten C. Schmidt Klaus Steinbach Eberhard v. Löw 《Environmental Sciences Europe》1998,10(5):289-293
Arsenic containing chemical warfare agents (cwa) are persistent in the environment and continue to contaminte soil and ground water. In this paper the chemical rections of the cwa diphenylarsine chloride (CLARK I), phenylarsine dichloride (PFIFFIKUS), ethylarsine dichloride (DICK) and of chlorovinyl arsenic compounds (LEWISITE) are shown. The posibilities of the detection and determination of this cwa and their metabolites are presented. 相似文献
135.
The effect of anoxia on the viability (as evidenced by hatching) of newly spawned and fully developed subitaneous eggs of three species of copepods, Acartia tonsa (Dana), Centropages hamatus (Lilljeborg), and Labidocera aestiva (Wheeler) was determined for eggs produced in the laboratory by adults collected from inshore waters of the northeastern Gulf of Mexico between January and August 1992. Hatching success decreased to 50% or less when eggs were exposed to oxygen concentrations <0.06 mll-1 for more than 12 d, except for newly spawned eggs of L. aestiva, which still showed 50% survival after 32 d of exposure to anoxia. For all three species, newly spawned eggs survived exposure to anoxia longer than fully developed eggs. The results indicate that the increasing occurrence of anoxia in estuarine and coastal waters could have a major impact on the population growth of these important food web organisms. 相似文献
136.
137.
R. W. Pohl E. Schmidt G. C. Hirsch H. Marquardt O. Harnisch 《Die Naturwissenschaften》1959,46(11):387-388
138.
139.
140.