全文获取类型
收费全文 | 9640篇 |
免费 | 0篇 |
专业分类
废物处理 | 766篇 |
环保管理 | 1206篇 |
综合类 | 932篇 |
基础理论 | 3105篇 |
污染及防治 | 1732篇 |
评价与监测 | 1005篇 |
社会与环境 | 894篇 |
出版年
2022年 | 1篇 |
2019年 | 1篇 |
2018年 | 1473篇 |
2017年 | 1371篇 |
2016年 | 1193篇 |
2015年 | 123篇 |
2014年 | 13篇 |
2013年 | 6篇 |
2012年 | 458篇 |
2011年 | 1337篇 |
2010年 | 689篇 |
2009年 | 596篇 |
2008年 | 876篇 |
2007年 | 1226篇 |
2006年 | 1篇 |
2005年 | 19篇 |
2004年 | 33篇 |
2003年 | 62篇 |
2002年 | 99篇 |
2001年 | 14篇 |
2000年 | 11篇 |
1999年 | 4篇 |
1998年 | 9篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1969年 | 1篇 |
1935年 | 2篇 |
排序方式: 共有9640条查询结果,搜索用时 953 毫秒
891.
We review a range of lack-of-fit tests suitable for assessing the appropriateness of the mean function in dose-response models.
The review encompasses both well-known tests and new tests based on recent developments in statistics, which we have extended
to the dose-response case. We argue that the classical methods are inadequate in certain situations, where the new tests may
be applied. Power comparisons are carried out by means of extensive simulation studies, covering both designs with and without
replicates at small and large sample sizes. Three datasets from dose-response applications illustrate differences and similarities
between the tests. The results suggest that the new tests perform better and exhibit a wider applicability. 相似文献
892.
With growing population and fast urbanization in Australia, it is a challenging task to maintain our water quality. It is
essential to develop an appropriate statistical methodology in analyzing water quality data in order to draw valid conclusions
and hence provide useful advices in water management. This paper is to develop robust rank-based procedures for analyzing
nonnormally distributed data collected over time at different sites. To take account of temporal correlations of the observations
within sites, we consider the optimally combined estimating functions proposed by Wang and Zhu (Biometrika, 93:459–464, 2006) which leads to more efficient parameter estimation. Furthermore, we apply the induced smoothing method to reduce the computational
burden. Smoothing leads to easy calculation of the parameter estimates and their variance-covariance matrix. Analysis of water
quality data from Total Iron and Total Cyanophytes shows the differences between the traditional generalized linear mixed
models and rank regression models. Our analysis also demonstrates the advantages of the rank regression models for analyzing
nonnormal data. 相似文献
893.
José S. Antunes do Carmo Mechteld ten Voorde Maria G. Neves 《Journal of Coastal Conservation》2011,15(4):531-546
Surfing has becoming more and more attractive in the past few decades, constituting nowadays an important source of revenue
for many countries with extensive coastlines. For this purpose and also for environmental reasons, the conventional ways of
protecting a coastline appear to entail some disadvantages. An innovative and interesting way of improving surfing capacities
and contributing to protect a local coastal zone is by means of multifunctional artificial reefs. A multifunctional artificial
reef (MFAR) is a submerged structure that serves several purposes; in particular, it may enhance the surfing possibilities
and the environmental value of the local area. This structure has some promising new aspects, too: first, it provides an unimpaired
visual amenity; second, it offers tourist and economic benefits by improving the surfing conditions; third, it can enhance
the environmental value of the area where it is built, and fourth, if designed properly, the down drift erosion can be minimal.
An appropriate reef design in terms of ‘surfability’, i.e. the possibility to surf a wave, for the Leirosa beach, located
to the south of Figueira da Foz, midway along Portugal’s West Atlantic coast, has been investigated. In order to achieve the
best design several steps were conducted. First, the performance of the Boussinesq-type COULWAVE model is tested with experimental
data. Next, this numerical model is used to define the best values for three design parameters: reef angle; geometry of the
reef (without or with a platform), and horizontal dimensions for the appropriate geometry. A preliminary design was achieved
step by step, making use of the theory and of the state of the art of multifunctional reefs. This reef geometry is used in
the numerical study. In terms of ‘surfability’ and for the conditions of the local coastline of Leirosa, the following values
were found for the main parameters: a reef angle of 66°; a structure height of 3.20 m; a reef geometry composed of a delta
without a platform; a reef submergence of 1.50 m, and a structure seaward slope of 1:10. 相似文献
894.
Flávia Noronha Dutra Ribeiro Jacyra Soares Amauri Pereira de Oliveira 《Environmental Fluid Mechanics》2011,11(6):551-572
This work investigates the capability of an oceanic numerical model dynamic and thermodynamically coupled to a three-dimensional
mesoscale atmospheric numerical model to simulate the basic features of the air–sea interaction in the coastal upwelling area
of Cabo Frio (RJ, Brazil). The upwelling/downwelling regime is an important feature in the oceanic circulation of Cabo Frio
and determines the sustainability of local ecosystems. This regime is predominantly driven by the atmospheric circulation
and is well documented, being suitable to be used as test reference for atmospheric and oceanic coupled and uncoupled models.
The oceanic boundary conditions, coastline shape and coupling effect have been tested. The uncoupled oceanic model forced
by a NE (SW) wind field generates a realistic upwelling (downwelling) phenomenon regardless of the proximity of the lateral
boundary and how realistic is the shape of the coastline. The atmospheric-oceanic coupled model generates an upwelling location
and intensity similar to the uncoupled simulation, but the upwelling is gradually enhanced by the sea-breeze circulation.
It also generates vertical profiles of mixing ratio that compare better to the observations than the uncoupled simulation
and air potential temperature and wind vertical profiles that represent particular features of the atmospheric circulation
at Cabo Frio. 相似文献
895.
Integrated remote sensing and GIS techniques for landslide hazard zonation: a case study Wadi Watier area,South Sinai,Egypt 总被引:3,自引:0,他引:3
Mohamed O. Arnous 《Journal of Coastal Conservation》2011,15(4):477-497
Natural hazard analysis involves mapping and identifying future hazardous zones through the analysis of the controls influencing
hazard initiation and occurrence. One of such natural hazard is the landslide. Landslides are amongst the most costly and
damaging natural hazards especially in mountain regions and are triggered mainly by seismic activity and/or rainfall. The
aim of the present study is to integrate Remote Sensing (RS) and Geographic Information System (GIS) tools to create thematic
layers for assessment and the estimation of landslide hazard zones in and surrounding the Wadi Watier area, South Sinai, Egypt.
Various factors, variables and/or parameters can be derived from thematic layers such as lithology, structural lineaments,
land-cover/land-use, terrain analysis and earthquakes. Intensity risk layers were created by using ERDAS Imagine 9.2, ARC
GIS 9.2 and ARC INFO 7.2.1 software. Enhanced Thematic Mapper (ETM+7) Landsat satellite images were used to discriminate and
extract structural lineaments, lithology and land-use/land-cover variables for the study area. The Digital Elevation Model
(DEM) was generated from digitized topographic maps to produce terrain analysis maps such as; slope, aspect, height elevation,
and 3D. The weighting score rating system based on the relative importance of various causal factors derived from RS data
and other thematic layers was used for landslide hazard zonation (LHZ). Based on these data, a simple algorithm was created
to classify the area into different risk zones. By overlaying all hazard layers a final landslide hazard map was produced.
Using trial and error and statistical methods the weight score rating values have been readjusted. GIS integration with RS
data can greatly facilitate classifying landslide hazard zones into low risk, moderate risk and high risk by using a slicing
operation. Seismic data are integrated with final the LHZ to generate a LHZ scenario map for the future and to draw up an
action plan of mitigation measures to avoid the damage, loss of life and socio-economic impacts in the study area. 相似文献
896.
897.
Serge Guillas Anna Bakare Jeremy Morley Richard Simons 《Journal of Coastal Conservation》2011,15(3):337-351
There is a need for decadal predictions of the seabed evolution, for example to inform resurvey strategies when maintaining
navigation channels. The understanding of the physical processes involved in morphological evolution, and the viability of
process models to accurately model evolution over these time scales, are currently limited. As a result, statistical approaches
are used to supply long-term forecasts. In this paper, we introduce a novel statistical approach for this problem: the autoregressive
Hilbertian model (ARH). This model naturally assesses the time evolution of spatially-distributed measurements. We apply the
technique to a coastal area in the East Anglian coast over the period 1846 to 2002, and compare with two other statistical
methods used recently for seabed prediction: the autoregressive model and the EOF model. We evaluate the performance of the
three methods by comparing observations and predictions for 2002. The ARH model enables a reduction of 10% of the root mean
squared errors. Finally, we compute the variability in the predictions related to time sampling using the jackknife, a method
that uses subsamples to quantify uncertainties. 相似文献
898.
The Turks and Caicos Islands are currently in the midst of an economic revolution from a marine-based provisional economy to a tourism economy. East Bay, South Caicos, is currently under construction with plans for a 160-unit condominium complex. Included in the project plan is removal of seagrass beds in front of the development to make a sandy beach for tourists. The aims of this study were to (i) describe the bathymetry and benthic habitat coverage of East Bay before dredging takes place and (ii) perform an economic valuation on the turtle grass beds that will be dredged using ecosystem valuation and emergy analysis techniques. The bathymetry survey revealed shallow waters (<1.5 m) until the reef drop off (~650 m offshore). Benthic habitat exhibits zonation following the general progression: sand plain, algal plain, seagrass, coral rubble and seagrass, rock and turf algae, and reef flat. Ecosystem services valued the proposed dredging area at USD $28,807 per year, compared to emergy analysis, which valued the proposed dredging site at USD $32,060 per year. The baselines presented in the study may facilitate a quantitative assessment of dredging impacts on turtle grass once dredging is complete and an economical cost-benefit-analysis of the dredging project to see whether the economic gains outweigh the ecological costs of dredging in front of the East Bay development. 相似文献
899.
900.
James A. R. Marshall 《Behavioral ecology and sociobiology》2011,65(3):503-512
Reconciling the evolution of altruism with Darwinian natural selection is frequently presented as a fundamental problem in
biology. In addition to an exponentially increasing literature on specific mechanisms that can permit altruism to evolve,
there has been a recent trend to establish general principles to explain altruism in populations undergoing natural selection.
This paper reviews and extends one approach to understanding the ultimate causes underlying the evolution of altruism and
mechanisms that can realise them, based on the Price equation. From the Price equation, we can see that such ultimate causes
equate to the different ways in which the frequency of an altruistic allele in a population can increase. Under this approach,
the ultimate causes underlying the evolution of altruism, given some positive fitness costs and benefits, are positive assortment
of altruistic alleles with the altruistic behaviour of others, positive deviations from additive fitness effects when multiple
altruists interact or bias in the inheritance of altruistic traits. In some cases, one cause can be interpreted in terms of
another. The ultimate causes thus identified can be realised by a number of different mechanisms, and to demonstrate its general
applicability, I use the Price equation approach to analyse a number of classical mechanisms known to support the evolution
of altruism (or cooperation): repeated interaction, ‘greenbeard’ traits, games played on graphs and payoff synergism. I also
briefly comment on other important points for the evolution of altruism, such as the ongoing debate over the predominant status
of inclusive fitness as the best way to understand its evolution. I conclude by arguing that analysing the evolution of altruism
in terms of its ultimate causes is the logical way to approach the problem and that, despite some of its technical limitations,
the Price equation approach is a particularly powerful way of doing so. 相似文献