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351.
Peter Miehle Michael Battaglia Peter J. Sands David I. Forrester Paul M. Feikema Stephen J. Livesley Jim D. Morris Stefan K. Arndt 《Ecological modelling》2009
In forest management and ecological research, consideration of the impacts and risks of climate change or management optimisation is complex. Computer models have long been applied as tools for these tasks. Process-based forest growth models claim to overcome the limitations of empirical statistical models, but the capacity of different process-based models and modelling approaches have rarely been compared directly. This study evaluates stepwise multiple regression models in comparison to four process-based modelling approaches (3-PG, 3-PG+, CABALA and Forest-DNDC) for greenfield predictions of Eucalyptus globulus plantation growth from 2 to 8 years after planting throughout southern Australia. 相似文献
352.
Changes in carbon use efficiency (CUE), which is defined as the ratio of net primary production (NPP) to gross primary production (GPP), were analyzed for Abies veitchii Lindl. forests with respect to stand development by developing a simple mathematical model incorporating data on physiological variables and leaf mass ratio. A decrease in CUE with stand development was successfully expressed as a function of stand biomass (y) based on the following three assumptions: (1) a power-law relationship between mean respiration and mean individual tree mass, (2) a power-functional relationship between mean gross primary production and mean individual tree mass, and (3) self-thinning relationship between stand biomass and density. Based on this model, a parameter of CUE–y relationship was defined, and it was clarified that CUE decrease with stand development is caused not by the ratio of specific respiration rate to specific gross photosynthetic rate, but by leaf mass ratio. Since CUE is high in young forests, helpful information on selecting woody species when planting seedlings was provided from the viewpoints of reducing CO2 in the atmosphere and global warming. 相似文献
353.
354.
国外酸雨试验研究动态 总被引:2,自引:0,他引:2
酸雨对环境污染和材料的侵蚀性日趋严重,近年国外对其影响开展一系列试验研究。本文介绍其试验研究的一些情况。 相似文献
355.
Australia and New Zealand share many historical and contemporary commonalities. These define five contemporary forest environmental frontiers—for First Nations peoples, between agriculture and forestry, in forest management, in urban and peri-urban environments, and in relation to climate change. In both countries, the First Nations frontier is expanding in scale and significance with those peoples’ rights to land and forests. Frontiers with agriculture and in forest management are longstanding but dynamic and as yet little realised in relation to the need for forest and landscape restoration. Both countries are highly urbanised, elevating the significance of the urban and peri-urban frontier, particularly in the context of climate change. In both countries, forests will be profoundly impacted by climate change and are central to mitigation and adaptation strategies. Experience within and intersections between the frontiers offer encouraging prospects for synergies and for learning between the two countries and more widely. 相似文献
356.
Effects of Natural Disasters on Conservation Policies: The Case of the 2008 Wenchuan Earthquake,China 总被引:1,自引:0,他引:1
Conservation policies are increasing in response to human-induced ecosystem degradation, but little is known about their interplay
with natural disasters. Through an analysis of satellite imagery and field data we evaluated the impacts of a devastating
earthquake on forest recovery and avoided forest loss estimated to have been obtained by two of the largest conservation programs
in the world. Results show that more than 10% of the forests in Wenchuan County, Sichuan province, China were immediately
affected by the 2008 earthquake, offsetting some gains in forest cover observed since the enactment of the conservation programs.
But without the enactment of these conservation programs, the combined effects of human disturbance and earthquake-induced
landslides could have severely reduced the region’s forest cover. The continuation—and enhancement—of incentives for participation
in conservation programs will be important for reducing the environmental impacts of the combined effects of human disturbance
and natural hazards not only in the study area but also in many disaster-prone regions around the world. 相似文献
357.
Assessments of adaptation options generally focus on incremental, homogeneous ecosystem responses to climate even though climate
change impacts can be big, fast, and patchy across a region. Regional drought-induced tree die-off in semiarid woodlands highlights
how an ecosystem crash fundamentally alters most ecosystem services and poses management challenges. Building on previous
research showing how choice of location is linked to adaptive capacity and vulnerability, we developed a framework showing
how the options for retaining desired ecosystem services in the face of sudden crashes depend on how portable the service
is and whether the stakeholder is flexible with regard to the location where they receive their services. Stakeholders using
portable services, or stakeholders who can move to other locations to obtain services, may be more resilient to ecosystem
crashes. Our framework suggests that entering into cooperative networks with regionally distributed stakeholders is key to
building resilience to big, fast, patchy crashes. 相似文献
358.
The Conversion of Cropland to Forest and Grassland Program (CCFG), which was initiated by the Chinese government in 1999,
is a cropland retirement program with integrated objectives for ecological preservation and local development. The purpose
of this article was to study the influencing factors of attitude and economic strategies in rural households toward the CCFG.
Rural households’ knowledge, attitude and economic strategies toward the CCFG were investigated through a questionnaire survey
in Qira, China. Influencing factors of attitude and strategies of households were analyzed using a logit model technique.
The analysis indicated that household’s income level, environmental knowledge of the program, and program implementation were
significant influencing factors in a household’s attitude toward the CCFG, while major influencing factors of household strategies
were their regional background and availability of income generation sources. Meaningful association was not found between
attitude and strategy choices. Rich households had more strategy choices, while poor households were usually confined to low
input strategies with uncertain income. To sustain their livelihood, the poor need extra assistances in marketing, loan granting,
employment training, information, and technical services. 相似文献
359.
Valuation of Spatial Configurations and Forest Types in the Southern Appalachian Highlands 总被引:1,自引:0,他引:1
Site-specific estimates of the values of spatial configuration and forest composition are presented. Amenity values of forest
patches are found to vary the most by urban and sprawling development patterns of specific areas and forest types. For example,
smaller patches of deciduous forest are more highly valued in the urban and sprawling areas of Greensboro, North Carolina,
whereas larger patches of deciduous forest are more highly valued in the urban and sprawling areas of Greenville, South Carolina.
Within the Greenville and Greensboro areas, visible landscape complexity is highly valued for deciduous and evergreen forest
patches, whereas lower visible landscape complexity, i.e., smoothly trimmed forest patch boundaries, is highly valued for
mixed forest patches. 相似文献
360.
This paper identifies human factors associated with high forest fire risk in Spain and analyses the spatial distribution of fire occurrence in the country. The spatial units were 6,066 municipalities of the Spanish peninsular territory and Balearic Islands. The study covered a 13-year series of fire occurrence data. One hundred and eight variables were generated and input to a dedicated Geographic Information System (GIS) to model different factors related to fire ignition. After exploratory analysis, 29 were selected to build a predictive model of human fire ignition using logistic regression analysis. The binary model estimated the probability of high or low occurrence of forest fires, as defined by an ignition danger index that is currently used by the Spanish forest service (number of fires divided by forest area in each municipality). Thirteen explanatory variables were identified by the model. They were related to agricultural landscape fragmentation, agricultural abandonment and development processes. The prediction agreement found between the model binary outputs and the historical fire data was 85.3% for the model building dataset (60% of municipalities). A slightly lower predictive power (76.2%) was found for the validation data (the remaining 40%). The probabilistic output of the logistic was significantly related to the raw ignition index (Spearman correlation of 0.710) used by the Spanish Forest Service. Therefore, the model can be considered a good predictor of human-caused fire risk, aiding spatial decisions related to prevention planning in Spanish municipalities. 相似文献