全文获取类型
收费全文 | 982篇 |
免费 | 18篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 34篇 |
废物处理 | 32篇 |
环保管理 | 173篇 |
综合类 | 114篇 |
基础理论 | 283篇 |
环境理论 | 1篇 |
污染及防治 | 253篇 |
评价与监测 | 68篇 |
社会与环境 | 43篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 27篇 |
2022年 | 32篇 |
2021年 | 14篇 |
2020年 | 12篇 |
2019年 | 29篇 |
2018年 | 23篇 |
2017年 | 33篇 |
2016年 | 39篇 |
2015年 | 25篇 |
2014年 | 42篇 |
2013年 | 84篇 |
2012年 | 35篇 |
2011年 | 81篇 |
2010年 | 52篇 |
2009年 | 42篇 |
2008年 | 46篇 |
2007年 | 55篇 |
2006年 | 59篇 |
2005年 | 32篇 |
2004年 | 32篇 |
2003年 | 35篇 |
2002年 | 33篇 |
2001年 | 19篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 11篇 |
1997年 | 14篇 |
1996年 | 15篇 |
1995年 | 6篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1976年 | 1篇 |
1965年 | 1篇 |
1941年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有1007条查询结果,搜索用时 569 毫秒
531.
van Hullebusch Eric D. Singh Nand K Mal Joyabrata 《Environmental science and pollution research international》2021,28(30):40217-40219
Environmental Science and Pollution Research - 相似文献
532.
We report that iron-reducing bacteria are primary mediators of anaerobic carbon oxidation in upland tropical soils spanning a rainfall gradient (3500-5000 mm/yr) in northeast Puerto Rico. The abundant rainfall and high net primary productivity of these tropical forests provide optimal soil habitat for iron-reducing and iron-oxidizing bacteria. Spatially and temporally dynamic redox conditions make iron-transforming microbial communities central to the belowground carbon cycle in these wet tropical forests. The exceedingly high abundance of iron-reducing bacteria (up to 1.2 x 10(9) cells per gram soil) indicated that they possess extensive metabolic capacity to catalyze the reduction of iron minerals. In soils from the higher rainfall sites, measured rates of ferric iron reduction could account for up to 44% of organic carbon oxidation. Iron reducers appeared to compete with methanogens when labile carbon availability was limited. We found large numbers of bacteria that oxidize reduced iron at sites with high rates of iron reduction and large numbers of iron reducers. The coexistence of large populations of iron-reducing and iron-oxidizing bacteria is evidence for rapid iron cycling between its reduced and oxidized states and suggests that mutualistic interactions among these bacteria ultimately fuel organic carbon oxidation and inhibit CH4 production in these upland tropical forests. 相似文献
533.
Species in a given trophic level occur in vastly unequal abundance, a pattern commonly documented but poorly explained for most taxa. Theoretical predictions of species density such as those arising from the metabolic theory of ecology hold well at large spatial and temporal scales but are not supported in many communities sampled at a relatively small scale. At these scales ecological factors may be more important than the inherent limits to energy use set by allometric scaling of mass. These factors include the amount of resources available, and the ability of individuals to convert these resources successfully into population growth. While previous studies have demonstrated the limits of macroecological theory in explaining local abundance, few studies have tested alternative generalized mechanisms determining abundance at the community scale. Using an assemblage of forest moth species found co-occurring as caterpillars on a single host plant species, we tested whether species abundance on that plant could be explained by mass allometry, intrinsic population growth, diet breadth, or some combination of these traits. We parameterized life history traits of the caterpillars in association with the host plant in both field and laboratory settings, so that the population growth estimate was specific to the plant on which abundance was measured. Using a generalized least-squares regression method incorporating phylogenetic relatedness, we found no relationship between abundance and mass but found that abundance was best explained by both intrinsic population growth rate and diet breadth. Species population growth potential was most affected by survivorship and larval development time on the host plant. Metabolic constraints may determine upper limits to local abundance levels for species, but local community abundance is strongly predicted by the potential for population increase and the resources available to that species in the environment. 相似文献
534.
Eric Parmentier Loïc Kéver Margarida Casadevall David Lecchini 《Marine Biology》2010,157(10):2317-2327
Synchronous underwater audio–video recordings and a passive acoustic detector were used to study the behaviour of Dascyllus flavicaudus. These damselfish produced sounds during six different behaviours and showed three different colour patterns while doing
so. These sounds can be grouped into three classes: sounds associated with (1) fighting; (2) mating/visiting and (3) chasing
and signal jumps. Moreover, the evolution of the different kinds of sound is discussed: the first calls could be a single
pulse originating in teeth snapping. Modifications in the rhythm and number of pulses allowed the fish to build new messages.
Daily recordings showed that sound production rates were higher at sunrise and sunset than during the day and that no sound
was produced during the night. However, the kinds of call were different: sunrise sounds seemed mainly associated with mating/visiting,
whereas the sounds associated with chasing and to signal jumps were mainly found at sunset. 相似文献
535.
Jeffrey N. Schinske Giacomo Bernardi David K. Jacobs Eric J. Routman 《Marine Biology》2010,157(1):123-134
We compared morphology and sequenced nuclear and mitochondrial genes from 11 populations of a previously genetically unstudied
“Baja California disjunct” species, the diamond turbot (Hypsopsetta guttulata). This species exhibits very limited adult movement and restriction to soft-bottom habitats but has a moderately long pelagic
larval duration. Therefore, if pelagic larval duration is correlated with gene flow between Gulf of California and Pacific
populations, we expect a reduced level of genetic and morphological differentiation. However, if adult habitat and ecology
have more effect on gene flow, we expect the populations in the two bodies of water to be more highly differentiated. We used
logistic regression to compare morphological features and phylogenetic and population genetic analyses to compare nucleotide
sequence data. Gulf of California H. guttulata are different from Pacific populations in morphology and both mitochondrial and nuclear gene sequences. MtDNA shows reciprocal
monophyly, and nuclear sequences from the Gulf of California formed a monophyletic group. Population genetic analyses also
suggest further population subdivision within the Pacific and within the Gulf of California. We argue that adult ecology has
a significant effect on migration rates among populations in the Pacific Ocean and the Gulf of California. 相似文献
536.
Inverse parameter estimation of individual-based models (IBMs) is a research area which is still in its infancy, in a context where conventional statistical methods are not well suited to confront this type of models with data. In this paper, we propose an original evolutionary algorithm which is designed for the calibration of complex IBMs, i.e. characterized by high stochasticity, parameter uncertainty and numerous non-linear interactions between parameters and model output. Our algorithm corresponds to a variant of the population-based incremental learning (PBIL) genetic algorithm, with a specific “optimal individual” operator. The method is presented in detail and applied to the individual-based model OSMOSE. The performance of the algorithm is evaluated and estimated parameters are compared with an independent manual calibration. The results show that automated and convergent methods for inverse parameter estimation are a significant improvement to existing ad hoc methods for the calibration of IBMs. 相似文献
537.
The fate of reactive tracers is often modelled by depth-averaged equations. When integrating the depth-resolved equations, it appears that the term describing the settling of particles is dependent on the concentration just above the bottom. Because in a depth-averaged framework this quantity is not available, the settling term needs to be parameterised. The most natural choice is to make the settling flux dependent on the average concentration. This approximation is acceptable if the water column is well mixed, but these conditions are not necessarily met in real applications. Therefore, this study aims at assessing and understanding the error made by using a depth-averaged model in a range of realistic conditions. For the definition of these conditions, typical values for the Scheldt Estuary and the Dutch-Belgian coast were taken. The realistic inspiration for the reactive tracer in this study is the fecal bacterium Escherichia coli, whose own dynamics are characterised by settling and gradual decay by mortality. In an attempt to understand the relative importance of several factors like settling, mortality, mixing and stratification on the error made by a depth-averaged approach, a number of simplified test cases were investigated. It follows that, as expected, the error is acceptable if the situation is mixing-dominated. However, the effect of mortality and stratification was less obvious in advance. For instance, it appeared that errors can also be significant if settling and mortality have the same characteristic timescales. Stratification often has the effect to increase the error made by the depth-averaged model. 相似文献
538.
Christofer Troedsson Jean-Marie Bouquet Carla M. Lobon Aliona Novac Jens C. Nejstgaard Sam Dupont Suncica Bosak Hans H. Jakobsen Nadezda Romanova Lene M. Pankoke Alejandro Isla Jörg Dutz Andrey F. Sazhin Eric M. Thompson 《Marine Biology》2013,160(8):2175-2187
Increasing pCO2 is hypothesized to induce shifts in plankton communities toward smaller cells, reduced carbon export rates and increased roles of gelatinous zooplankton. Appendicularians, among the most numerous pan-global “gelatinous” zooplankton, continuously produce filter-feeding houses, shortcutting marine food webs by ingesting submicron particles, and their discarded houses contribute significantly to carbon fluxes. We present a first mesocosm-scale study on the effects of temperature, pCO2 and bloom structures on the appendicularian, Oikopleura dioica. There were effects of temperature and nutrients on phytoplankton communities. No shifts in functional phytoplankton groups, nor changes in particle sizes/morphotypes, known to impact appendicularian feeding, were observed under manipulated pCO2 conditions. However, appendicularian abundance was positively correlated with increased pCO2, temperature and nutrient levels, consistent with hypotheses concerning gelatinous zooplankton in future oceans. This suggests appendicularians will play more important roles in marine pelagic communities and vertical carbon transport under projected ocean acidification and elevated temperature scenarios. 相似文献
539.
This paper criticises the conclusions and the unanswered questions in the National Institute of Standards and Technology (NIST)'s official report on the evacuation of the World Trade Center in New York City, United States, on 11 September 2001. It reviews the extent to which the report disregards several conventional statistical methods and comments on the NIST's refusal to share the machine‐readable data file with the scientific community for replication and further analysis. Problems lie in the sampling methods employed, the treatment of missing data, the use of ordinary least squares (OLS) with binary dependent variables, the failure to document the scalability of the scales used, the lack of tests to check for constant error variance, and the absence of overall fit tests of the model. There are also conceptual and theoretical issues, such as the absence in the report of considerations of the influence of group‐level processes and their impact on the collective behaviour of evacuating collectivities. 相似文献
540.
Models of habitat selection often assume that organisms choose habitats based on their intrinsic quality, regardless of the position of these habitats relative to low-quality habitats in the landscape. We created a habitat matrix in which high-quality (predator-free) aquatic habitat patches were positioned adjacent to (predator-associated) or isolated from (control) patches with single or two species of caged predators. After 16 days of colonization, larval insect abundance was reduced by 50% on average in both the predator and predator-associated treatments relative to isolated controls. Effects were largely similar among predator treatments despite variation in number of predator species, predator biomass, and whether predators were native or nonnative. Importantly, the strength of effects did not depend on whether predators were physically present. These results demonstrate that predator cues can cascade with equal strength across ecological boundaries, indirectly altering community assembly via habitat selection in intrinsically high-quality habitats. 相似文献