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961.
Persistence models for mark-recapture 总被引:1,自引:0,他引:1
The stable of models available for analyzing mark-recapture data (Otis et al. Wild Momogr 66:135, 1978) includes those having
behavioral characteristics, time variation, heterogeneity, along with combinations of those characteristics. This paper proposes
use of a series of models based on the persistence model of Ramsey and Usner (Biometrics 59:331–339, 2003). We show that persistence
can be modeled in combination with behavior and with time variation. We apply the persistence model to situations in which
capture occasions are not equally-spaced in time. Two case studies illustrate the use of these extended persistence models. 相似文献
962.
Although most UK sand dune systems are now fossilized, with little mobility and reducing amounts of bare sand, they support
important populations and assemblages of terrestrial invertebrates. Offering open conditions, warm substrates and a range
of habitats and habitat structures, they have become increasingly significant as other coastal habitats have been lost. In
Wales, 680 Red Data Book and Nationally Scarce species have been recorded from dunes. 109 species in the UK are restricted
to dunes, and in Wales there are an additional 145 species confined to dunes and 208 species strongly associated with dunes.
Of these, 172 species are dependent upon bare and sparsely-vegetated sand, in grey dunes and early-successional dune grassland,
at some stage of their life cycle, rising to 292 species if those associated with the strandline, foredunes, yellow dunes
and pioneer dune slacks are included, equating to 63% of the 462 dune species. Bees and wasps are particularly well represented,
with 278 species (68% of the Welsh fauna) recorded on Welsh dunes, including 17 obligates and 44 species with a strong dependence,
52 of which are associated with bare and sparsely-vegetated sand. Key to maintaining invertebrate populations on UK dunes
is the provision of bare sand but in Wales, bare sand accounts for only 1.7% of the total sand dune resource. As a more appropriate
bare sand threshold is likely to range between 10 and 30%, radical action is required to re-mobilize at least the key sand
dune systems. 相似文献
963.
Akshay A. Gowardhan Michael J. Brown Eric R. Pardyjak 《Environmental Fluid Mechanics》2010,10(3):311-328
This work describes and evaluates a pressure solver that has been incorporated into a fast response three-dimensional building-resolving
diagnostic wind modeling system. The solver computes the three-dimensional pressure field around buildings and on exterior
walls in terms of a coefficient of pressure by solving a simplified pressure Poisson equation (that neglects turbulence stresses
in the Navier-Stokes) for incompressible flow. The input to the solver is the three-dimensional mean wind field obtained from
a fast response empirical-diagnostic urban wind model. The present study is an evaluation of the pressure solver using wind-tunnel
data for flow normal to and at a 45° angle to an isolated cubical building. Results for the normal incident wind angle case
indicate that the model satisfactorily reproduces the general spatial patterns and the magnitude of the pressure difference
around much of the cube. Details of the flow field that are not satisfactorily predicted include the spatial distribution
of pressure on the roof and the lower half of the front side of the building and the magnitude along the sidewalls where pressures
are over predicted. The results for the 45° case show reasonable agreement between the model and experiments on the front
and the back walls, but over predict pressures on the leading edge of the rooftop. Regions with poor pressure predictions
appear to be a result of unsatisfactory mean wind modeling. 相似文献
964.
Mohammad Salehi Mohammad Mohammadi J. N. K. Rao Yves G. Berger 《Environmental and Ecological Statistics》2010,17(1):111-123
Adaptive cluster sampling (ACS) is an efficient sampling design for estimating parameters of rare and clustered populations.
It is widely used in ecological research. The modified Hansen-Hurwitz (HH) and Horvitz-Thompson (HT) estimators based on small
samples under ACS have often highly skewed distributions. In such situations, confidence intervals based on traditional normal
approximation can lead to unsatisfactory results, with poor coverage properties. Christman and Pontius (Biometrics 56:503–510,
2000) showed that bootstrap percentile methods are appropriate for constructing confidence intervals from the HH estimator.
But Perez and Pontius (J Stat Comput Simul 76:755–764, 2006) showed that bootstrap confidence intervals from the HT estimator
are even worse than the normal approximation confidence intervals. In this article, we consider two pseudo empirical likelihood
functions under the ACS design. One leads to the HH estimator and the other leads to a HT type estimator known as the Hájek
estimator. Based on these two empirical likelihood functions, we derive confidence intervals for the population mean. Using
a simulation study, we show that the confidence intervals obtained from the first EL function perform as good as the bootstrap
confidence intervals from the HH estimator but the confidence intervals obtained from the second EL function perform much
better than the bootstrap confidence intervals from the HT estimator, in terms of coverage rate. 相似文献
965.
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the urban atmosphere and the atmospheric pollutants to be identified
as the most suspected carcinogens. In early measurements of urban PAH concentrations in Tehran area, the correlation between
concentrations of different species indicated that automobiles were the predominant source of emission of PAHs in this city.
From the diagnostic ratios, the results indicated that PAHs in the ambient air in Tehran originate primarily from diesel and
gasoline engines, but contribution of the related diesel emission is apparently higher, or dominant, at the sampling sites
and therefore considered as the major emission of PAHs in the ambient air. 相似文献
966.
J. Carneiro L. M. Cardenas D. J. Hatch H. Trindade D. Scholefield C. D. Clegg P. Hobbs 《Environmental Chemistry Letters》2010,8(3):237-246
Nitrous oxide (N2O) affects climate change as a greenhouse gas and indirectly contributes to stratospheric ozone depletion. The main source
of N2O in soils is denitrification which requires high soil moisture, carbon and nitrate. Nitrification inhibitors can be used
to mitigate emissions of N2O from soils. In Portugal, fertilisers are often applied when soils are still relatively warm and moist conditions conducive
to denitrification. A Portuguese arable soil was inhibited with dicyandiamide, a nitrification inhibitor and the effect on
soil microbiological activity and composition was determined after 46 days. Soils were then incubated and received carbon
and ammonium under high soil water conditions and mineral N and N2O fluxes were measured during 22 days. We found that dicyandiamide decreased microbial populations and activity, but did not
alter composition. Pre-conditioning of the soil with dicyandiamide was 80% more effective in reducing fluxes of N2O than simultaneous application with fertiliser. 相似文献
967.
Caio F. Gromboni George L. Donati Wladiana O. Matos Eduardo F. A. Neves Ana Rita A. Nogueira Joaquim A. Nóbrega 《Environmental Chemistry Letters》2010,8(1):73-77
Efficiency of metabisulfite and a commercial steel wool as reducing agents in the removal of Cr(VI) from wastewaters was evaluated.
Chromium(VI) was converted to Cr(III), precipitated with NaOH, and removed by filtration. A reduction of more than 1.0 × 105 and 4.0 × 105 fold in total Cr and the Cr(VI) concentrations, respectively, was observed by employing steel wool masses as low as 0.4420 g
to 30-mL solutions of wastewater. Chromium(III) hydroxide obtained after the treatment was recycled and used as marker in
cattle nutrition studies. The liquid residue obtained after the treatment was reused as precipitation agent replacing NaOH. 相似文献
968.
A surfactant mediated cloud point extraction (CPE) procedure has been developed to remove color from wastewater containing
malachite green using Triton X-100 as non-ionic surfactant. The effects of the concentration of the surfactant, temperature
and salt concentration on the different concentrations of dye have been studied and optimum conditions were obtained for the
removal of malachite green. The concentration of malachite green in the dilute phase was measured using UV–Vis spectrophotometer.
It was found that the separation of phases was complete and the recovery of malachite green was very effective in the presence
of NaCl as an electrolyte. The results showed that up to 500 ppm of malachite green can quantitatively be removed (>95%) by
CPE procedure in a single extraction using optimum conditions. 相似文献
969.
970.
R. Hendler 《Environmental Sciences Europe》2010,22(2):85-90
This article is based on a speech held at the annual conference of the German Chemical Society (working group Environmental Chemistry and Ecotoxicology) on 23 September 2009 in Trier. Despite strong arguments for interdisciplinary co-operation in the field of law and natural sciences, it still appears as a rather rare phenomenon in the current research environment. This is partly due to the difficulties emerging from the increasing specialization and diversification in sciences. Beyond that, the current possibilities of third-party funding, not least aimed at initiating and intensifying interdisciplinary projects, provide a comparatively weak incentive to jurists. Nonetheless, there are indications for a change in the near future. However, at least chemical law (as well as for example nature conservation law) offers a range of starting points for a productive co-operation among jurists and natural scientists. 相似文献