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901.
William D. Shuster Dennis Lye Armah De La Cruz Lee K. Rhea Katharine O'Connell Amanda Kelty 《Journal of the American Water Resources Association》2013,49(4):753-765
The collection, storage, and reuse of rainwater collected in rain barrels from urban rooftop areas assists municipalities in achieving stormwater management objectives and in some areas also serves as an adjunct resource for domestic water supplies. In this study, rainwater reuse and levels of select microbial indicators were monitored for six residential rain barrels located in the Shepherd Creek watershed of Cincinnati, Ohio. Water from rain barrels typically had poor microbial quality and was used for watering indoor and outdoor plants. Rain barrel water chemistry was slightly acidic, exhibited wide ranges in conductivity, turbidity, and total organic carbon (TOC) concentrations and gave no evidence of the presence of cyanobacterial microcystin toxins. Selected microbial water‐quality indicators indicated that counts of total coliform and enterococci were consistently above U.S. Environmental Protection Agency standards for secondary recreational contact water‐quality standards. Residential rain barrels can provide water appropriate for low‐contact reuses (such as plant watering), although there may be transient periods of high levels of indicator bacteria in the collected water. 相似文献
902.
A commercially available thermal-infrared scanning system was used to survey populations of several wildlife species. The
system's ability to detect species of different sizes in varying habitats relative to conventional survey methods, to differentiate
between species in the same habitat, and the influence of environtmental factors on operational aspects of employing this
technology in the field were evaluated. Total costs for the surveys were approximately $0.36/ha. There were marked discrepancies
in the counts of untrained observers and those from trained analysis. Computer-assisted analysis of infrared imagery recorded
52% fewer deer than were estimated from drive counts, and densities of moose were five times those estimated from conventional
aerial methods. By flying concentric circles and using telephoto, detailed counts of turkeys and deer were possible. With
the aid of computer-assisted analysis, infrared thermography may become a useful wildlife population survey tool. More research
is needed to verify the actual efficiency of detection by combining aerial scans with ground truthing for a variely of species
and habitals. 相似文献
903.
Steven Shimoda H.William Prengle Jr James M. Symons 《Waste management (New York, N.Y.)》1997,17(8):507-515
This paper presents the chemical reaction engineering development of the H2O2/VisUV photo-oxidation process for treatment of hazardous waterborne substances, that occur in groundwater, leachates, and industrial wastewater. Reaction results, on benzene (BNZ), dichlorobenzene (DCB), trichloroethene (TCE), trichloroethane (TCA), and carbon tetrachloride (CTC), have been obtained, providing engineering data and models that can be used to size full-scale equipment. A photochemical flow stirred tank reactor (pcfSTR) and a photo-chemical tubular flow reactor (pcTFR) were used in the experimental work. Two experimental discoveries were made in the course of the work: (1) conventional thermal kinetics do not apply, the rate controlling variable is the photon flux, and (2) for the photo-chemical reactors used, the pcfSTR was more effective than the pcTFR. The following sub-topics are discussed: reaction mechanism, reactor hydrodynamics, photon flux effects, typical reaction data (on benzene and trichloroethane), and rate constants. 相似文献
904.
Stefan Garthe William A. Montevecchi Gilles Chapdelaine Jean-Francois Rail April Hedd 《Marine Biology》2007,151(2):687-694
In order to forage and to provision offspring effectively, seabirds negotiate a complex of behavioural, energetic, environmental
and social constraints. In first tests of GPS loggers with seabirds in North America, we investigated the foraging tactics
of free-ranging northern gannets (Sula bassana) at a large and a medium-sized colony that differed in oceanography, coastal position and prey fields. Gannets at Low Arctic
colony (Funk Island) 50 km off the northeast coast of Newfoundland, Canada provisioned chicks almost entirely with small forage
fish (capelin Mallotus villosus, 89%), while at boreal colony (Bonaventure Island) 3 km from shore in the Gulf of St. Lawrence, Quebec, Canada, large pelagic
fish dominated parental prey loads (Atlantic mackerel Scomber scombrus 50%, Atlantic herring Clupea harengus 33%). Mean foraging range and the total distance travelled per foraging trip were significantly greater at the larger inshore
colony (Bonaventure) than at the smaller offshore colony (Funk Island; 138 and 452 km vs. 64 and 196 km, respectively). Gannets
from Funk Island consistently travelled inshore to forage on reproductive capelin shoals near the coast, whereas foraging
flights of birds from Bonaventure were much more variable in direction and destination. Birds from the Low Arctic colony foraged
in colder sea surface water than did birds from the boreal colony, and dive characteristics differed between colonies, which
is concordent with the difference in prey base. Differences between the colonies reflect oceanographic and colony-size influences
on prey fields that shape individual foraging tactics and in turn generate higher level colony-specific foraging “strategies”. 相似文献
905.
Neighborhood analyses of canopy tree competition along environmental gradients in New England forests. 总被引:2,自引:0,他引:2
Charles D Canham Michael J Papaik María Uriarte William H McWilliams Jennifer C Jenkins Mark J Twery 《Ecological applications》2006,16(2):540-554
We use permanent-plot data from the USDA Forest Service's Forest Inventory and Analysis (FIA) program for an analysis of the effects of competition on tree growth along environmental gradients for the 14 most abundant tree species in forests of northern New England, USA. Our analysis estimates actual growth for each individual tree of a given species as a function of average potential diameter growth modified by three sets of scalars that quantify the effects on growth of (1) initial target tree size (dbh), (2) local environmental conditions, and (3) crowding by neighboring trees. Potential growth of seven of the 14 species varied along at least one of the two environmental axes identified by an ordination of relative abundance of species in plots. The relative abundances of a number of species were significantly displaced from sites where they showed maximum potential growth. In all of these cases, abundance was displaced to the more resource-poor end of the environmental gradient (either low fertility or low moisture). The pattern was most pronounced among early successional species, whereas late-successional species reached their greatest abundance on sites where they also showed the highest growth in the absence of competition. The analysis also provides empirical estimates of the strength of intraspecific and interspecific competitive effects of neighbors. For all but one of the species, our results led us to reject the hypothesis that all species of competitors have equivalent effects on a target species. Most of the individual pairwise interactions were strongly asymmetric. There was a clear competitive hierarchy among the four most shade-tolerant species, and a separate competitive hierarchy among the shade-intolerant species. Our results suggest that timber yield following selective logging will vary dramatically depending on the configuration of the residual canopy, because of interspecific variation in the magnitude of both the competitive effects of different species of neighbors and the competitive responses of different species of target trees to neighbors. The matrix of competition coefficients suggests that there may be clear benefits in managing for specific mixtures of species within local neighborhoods within stands. 相似文献
906.
Robin M. Reich Raymond L. Czaplewski William A. Bechtold 《Environmental and Ecological Statistics》1994,1(3):201-217
In this study a cross-correlation statistic is used to analyse the spatial relationship among stand characteristics of natural, undisturbed shortleaf pine stands sampled during 1961–72 and 1972–82 in northern Georgia. Stand characteristics included stand age, site index, tree density, hardwood competition, and mortality. In each time period, the spatial cross-correlation statistic was used to construct cross-correlograms and cumulative cross-correlograms for all significant pairwise combination of stand characteristics. Both the cross-correlograms and cumulative cross-correlograms identified small-scale clustering and weak directional gradients for different stand characteristics in each time period. The cumulative cross-correlograms, which are based on inverse distance weighting were more sensitive in detecting small-scale clustering than the cross-correlograms based on a 0–1 weighting. Further analysis suggested that the significant cross-correlation observed among basal area growth and other stand characteristics were due, in a large part, on a subset of sample plots located in the northern part of the state, rather than regional or broad-scale variation as first thought. The ability to analyse the spatial relationship between two or more response surfaces should provide valuable insight in the development of ecosystem level models and assist decision makers in formulating pertinent policy on intelligent multiresource management. 相似文献
907.
The paper maintains that, as a means toward achieving the ideal of a sustainable development, industrial waste should best be regarded in business-economic terms as having the same basic status as regular products. It is shown how an approach to proportioning industrial costs to waste that is described can be applied to the Polluter-Pays Principle in a way incorporating this principle into a company's internal estimation system. In two case studies presented, use of this approach is found to generate a waste-reducing incentive through showing waste to have a negative impact on estimates of profit. 相似文献
908.
Puerto Rican Parrots and Potential Limitations of the Metapopulation Approach to Species Conservation 总被引:1,自引:0,他引:1
909.
Dr. William C. Metz 《Environmental geochemistry and health》1982,4(4):131-140
After a lapse of almost two decades, US energy and mining companies are once again involving themselves with worker housing. Reinvolvement began in the 1970s. It is in response to a recognition of the fiscal consequences of project delays and an industry responsibility to both workers and project area communities. It differs from the heavy reliance on company towns which were prevalent in the US during the 19th and early 20th Centuries. Industry involvement now relies not only on supply, but on stimulation. A greater variety of housing initiatives is being utilised and a company must carefully select the housing initiative best suited to its circumstances. These initiatives need to be guided by the following set of decision guidelines: (1) housing function; (2) housing user; (3) housing type and quantity needs; (4) monetary expectations; (5) role of the industry; (6) housing unit location; (7) responsibilities after housing is completed; and (8) amenities and community sharing. Then, housing involvement must be reviewed in light of past and present industry experiences. Innovative ideas need to be evaluated with respect to proven initiatives, as well as their presumed goal and potential for success.Study performed under Contract No. DE-AC02-76CH00016 with the U.S. Department of Energy 相似文献
910.
Models of parasite-mediated sexual selection have thus far overlooked the potential effects of parasites of females on their
hosts’ ability to choose mates. A set of models addressing this issue is developed, each building on the previous one to add
complexity and realism to the framework. The selection coefficient for parasite immunity and brightness is estimated using
the ratio of the fitness of susceptible males to the fitness of immune males. Parasite-induced reduction in female choosiness
can substantially relax the selection for bright, immune males, especially when: (1) immunity to parasites is rare in the
population, (2) parasites are not highly aggregated within the host population, (3) parasites are abundant, and (4) the effects
of parasites on male brightness or female choosiness are severe. Parasite-induced variability in male brightness is most likely
to occur in populations in which parasites are abundant and not aggregated; if females in those populations show a reduced
preference for bright males, sexual selection for brightness (and parasite immunity) will still operate but exert a weaker
selective pressure.
Received: 4 November 1994/Accepted after revision: 9 September 1995 相似文献