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601.
602.
603.
Mechanistic Virtual Modeling: Coupling a Plant Simulation Model with a Three-dimensional Plant Architecture Component 总被引:3,自引:0,他引:3
Eric Jallas Ron Sequeira Pierre Martin Sam Turner Petraq Papajorgji 《Environmental Modeling and Assessment》2009,14(1):29-45
The aim of this research is to integrate plant architectural modeling or “visualization modeling” and “mechanistic” or physiologically
based modeling to describe how a real plant functions using a virtual crop. Virtual crops are life-like computer representations
of crops based on individual plants and including the representation of the substrate on which the plants grow. The integration
of a three-dimensional expression and the mechanistic model of plant development and growth requires the knowledge of the
position of the organs along the different plant axes (the topology), their sizes, their forms, and their spatial orientation.
The plant simulation model simulates the topology and organ weight or length. The superposition of spatial position and the
topology produces the architecture of the plant. The association between sizes and organs creates what we refer to as the
plant morphological model. Both components, the architectural model and the morphology model, are detailed in this paper.
Once the integration is complete, the system produces a movie-like animation that shows the plant growing. The integrated
model may simulate one or several plants growing simultaneously (in parallel). Visual capabilities make the proposed system
very unique as it allows users to judge the results of the simulation the same way a farmer judges the situation of the crops
in real life, by visually observing the field. 相似文献
604.
Evaluating Spatio-temporal Complexities of Forest Management: An Integrated Agent-based Modeling and GIS Approach 总被引:1,自引:0,他引:1
The objective of this study is to integrate agent-based modeling and geographic information systems (GIS) for examining how
interactions within forest management lead to patterns of land-cover change. Specifically, this study evaluates how management
agents behave in the presence of variable timber prices, harvesting costs, and accessibility to timber and how their actions
influence the spatial characteristics of the forest landscape over time. The GIS calculates the average harvested patch size,
number of patches, and total harvested area as measures of emergent patterns resulting from agent actions. The results from
the agent-based GIS model reveal that good economic conditions lead to few but large harvested patches, while deteriorating
conditions will see more patches of smaller size if forest companies have access to high-quality timber. This study emphasizes
the need for a complex systems approach to forest management as the model illustrates how system elements interact in a manner
to produce emergent spatial patterns over time. 相似文献
605.
Modeling Runoff Response to Land Cover and Rainfall Spatial Variability in Semi-Arid Watersheds 总被引:5,自引:0,他引:5
Mariano Hernandez Scott N. Miller David C. Goodrich Bruce F. Goff William G. Kepner Curtis M. Edmonds K. Bruce Jones 《Environmental monitoring and assessment》2000,64(1):285-298
Hydrologic response is an integrated indicator of watershed condition, and significant changes in land cover may affect the overall health and function of a watershed. This paper describes a procedure for evaluating the effects of land cover change and rainfall spatial variability on watershed response. Two hydrologic models were applied on a small semi-arid watershed; one model is event-based with a one-minute time step (KINEROS), and the second is a continuous model with a daily time step (SWAT). The inputs to the models were derived from Geographic Information System (GIS) theme layers of USGS digital elevation models, the State Soil Geographic Database (STATSGO) and the Landsat-based North American Landscape Characterization classification (NALC) in conjunction with available literature and look up tables. Rainfall data from a network of 10 raingauges and historical stream flow data were used to calibrate runoff depth using the continuous hydrologic model from 1966 to 1974. No calibration was carried out for the event-based model, in which six storms from the same period were used in the calculation of runoff depth and peak runoff. The assumption on which much of this study is based is that land cover change and rainfall spatial variability affect the rainfall-runoff relationships on the watershed. To validate this assumption, simulations were carried out wherein the entire watershed was transformed from the 1972 NALC land cover, which consisted of a mixture of desertscrub and grassland, to a single uniform land cover type such as riparian, forest, oak woodland, mesquite woodland, desertscrub, grassland, urban, agriculture, and barren. This study demonstrates the feasibility of using widely available data sets for parameterizing hydrologic simulation models. The simulation results show that both models were able to characterize the runoff response of the watershed due to changes of land cover. 相似文献
606.
Mark E. Jensen Roland L. Redmond Jeff P. Dibenedetto Patrick S. Bourgeron Iris A. Goodman 《Environmental monitoring and assessment》2000,64(1):197-212
The Little Missouri National Grasslands (LMNG) of western North Dakota support the largest permitted cattle grazing use within all lands administered by the USDA, Forest Service, as well as critical habitat for many wildlife species. This fact, coupled with the need to revise current planning direction for range allotments of the LMNG, necessitated that a broad-level characterization of ecosystem integrity and resource conditions be conducted across all lands within the study area (approximately 800,000 hectares) in a rapid and cost-effective manner. The approach taken in this study was based on ecological classifications, which effectively utilized existing field plot data collected for a variety of previous inventory objectives, and their continuous spatial projection across the LMNG by maps of both existing and potential vegetation. These two map themes represent current and reference conditions (existing vs. potential vegetation); their intersection allowed us to assign various ecological status ratings (i.e., ecosystem integrity and resource condition) based on the degree of departure between current and reference conditions. In this paper, we present a brief review of methodologies used in the development of ecological classifications, and also illustrate their application to assessments of rangeland health through selected maps of ecological status ratings for the LMNG. 相似文献
607.
A geographic information system (GIS)-based approach with spatial analysis advantages was developed to optimize the total
emission control scheme on air pollution in Lanzhou, combined with Models-3 modeling system and a linear programming model.
GIS system is mainly used for establishing a multifactor assessment model to quantitatively divide environmental functional
zone, and also used for selecting control sites in linear programming model. The results show that most of the urban area
belongs to the second type of function, which is 122.8 km2 occupying about 76.5% and the third type of about 32.9 km2 occupying 20.5%. To reach the air quality up to the national standard in the entire control area, some large-emission factories
need to cut emissions from 19% to 27%. For small but low-emission height sources, the cut may be as high 40%. The improvement
of the ecological environment is urgently needed for controlling the background particle pollution in Lanzhou city. 相似文献
608.
K. Omasa F. Hosoi T. M. Uenishi Y. Shimizu Y. Akiyama 《Environmental Modeling and Assessment》2008,13(4):473-481
In this study, we confirmed the utility of airborne and portable on-ground scanning light detection and ranging (LIDARs) for
three-dimensional visualization of an urban park and quantification of biophysical variables of trees in the park. The digital
canopy height model (DCHM) and digital terrain model generated from airborne scanning LIDAR data provided precise images of
the ground surface and individual tree canopies. The heights of 166 coniferous and broadleaf trees of 11 species in the park
were estimated from the DCHM images with slight underestimation (mean error = −0.14 m, RMSE = 0.30 m). Portable on-ground
scanning LIDAR provided images of individual trees with detailed features. Tree height and trunk diameter were estimated to
be within 0.31 m and 1 cm, respectively, from the on-ground LIDAR images. We combined airborne and on-ground LIDAR images
to overcome blind regions and created a complete three-dimensional model of three standing trees. The model allowed not only
visual assessment from all viewpoints but also quantitative estimation of canopy volume, trunk volume, and canopy cross-sectional
area. 相似文献
609.
Exposure to perchlorate is widespread in the United States and many studies have attempted to character the perchlorate exposure by estimating the average daily intakes of perchlorate. These approaches provided population-based estimates, but did not provide individual-level exposure estimates. Until recently, exposure activity database such as CSFII, TDS and NHANES become available and provide opportunities to evaluate the individual-level exposure to chemical using exposure surveillance dataset. In this study, we use perchlorate as an example to investigate the usefulness of urinary biomarker data for predicting exposures at the individual level. Specifically, two analyses were conducted: (1) using data from a controlled human study to examine the ability of a physiologically based pharmacokinetic (PBPK) model to predict perchlorate concentrations in single-spot and cumulative urine samples; and (2) using biomarker data from a population-based study and a PBPK model to demonstrate the challenges in linking urinary biomarker concentrations to intake doses for individuals. Results showed that the modeling approach was able to characterize the distribution of biomarker concentrations at the population level, but predicting the exposure-biomarker relationship for individuals was much more difficult. The type of information needed to reduce the uncertainty in estimating intake doses, for individuals, based on biomarker measurements is discussed. 相似文献
610.
Zhenxing Chi Rutao Liu Hong You Donglin Wang 《Journal of environmental science and health. Part. B》2013,48(12):978-984
Tetracycline (TC) is a widely used veterinary drug in animal breeding and fishery. Because of its low bioavailability, the TC residue extensively exists in the environment (e.g. soils, lakes and rivers), which can enter the human body, being potentially harmful. Hemoglobin (Hb) is a protein responsible for oxygen carrying in the vascular system of animals. The aim of this study was to investigate the interaction of bovine hemoglobin (BHb) with TC through spectroscopic and molecular modeling methods. The experimental results revealed that TC can interact with BHb with one binding site to form a TC-BHb complex, mainly through van der Waals interactions and hydrogen bonds. The UV-visible absorption, synchronous fluorescence, and circular dichroism (CD) results revealed that the binding of TC can cause conformational and some microenvironmental changes of BHb, which may affect BHb physiological functions. The synchronous fluorescence experiment disclosed that TC binds into BHb central cavity, which was verified by molecular modeling study. The work contributes to clarify the molecular mechanism of TC toxicity in vivo. 相似文献