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排序方式: 共有1146条查询结果,搜索用时 15 毫秒
941.
942.
Jan Stenis 《Waste management & research》2005,23(1):13-19
This paper describes a methodology for estimating the true internal costs of construction waste, aimed at promoting environmentally friendly waste management. The study employs cost-benefit analysis, contribution margin analysis, the polluter-pays principle and a mathematical model: the model for Efficient Use of Resources for Optimal Production Economy (EUROPE), which has been introduced previously by the author for assigning industrial costs to waste. The calculations are performed on construction waste created in a case study of a building project. Moreover, waste is regarded as, in a business sense, having the same basic status as any normal industrial product, namely the 'equality principle'. Application of the methodology is suggested to create incentives for environmental and profitability improvement in construction companies and other types of industrial sectors. The results of the case study show the generation of construction waste to substantially decrease the final operating income, due to the internal shadow price cost it creates. This paper is intended to reduce the gap between the choice of waste management procedures and their economic impact, the overall objective being to accomplish an improved industrial environmental situation. 相似文献
943.
944.
Jan Anne Annema Carl Koopmans 《Journal of Environmental Planning and Management》2015,58(9):1635-1648
Scientific debates on environmental impacts in cost-benefit analysis (CBA) focus on methodological questions. The literature, however, contains very little information on the influence of these debates on CBAs made in spatial planning practice. In this paper, this gap is filled by a qualitative analysis of 67 CBAs made in the Netherlands between 2000 and 2011. From the literature on environmental valuation, we derive criteria to evaluate the quality of CBA practice, such as completeness and the inclusion of uncertainties. The analysis shows that in many cases relevant environmental effects are omitted or not monetised. Moreover, non-monetised effects are often not included in CBA conclusions. If impacts are monetised, the methods used are frequently not very sophisticated. The consequences of assumptions are often not communicated, for example, where high discount rates make long-term effects seem unimportant. In this research we identify four main points for good practice. 相似文献
945.
Silje Hogner Terje Laskemoen Jan T. Lifjeld Václav Pavel Bohumír Chutný Javier García Marie-Christine Eybert Ekaterina Matsyna Arild Johnsen 《Behavioral ecology and sociobiology》2013,67(8):1205-1217
Spermatozoa are among the most variable animal cell types, and much research is currently directed towards explaining inter- and intraspecific variation in sperm form and function. Recent comparative studies in passerine birds have found associations between the level of sperm competition and both sperm length and sperm velocity. In species with sperm competition, postcopulatory sexual selection may shape the morphology of sperm as adaptations to the female environment. The speed of evolutionary change in sperm morphology at the species level is largely unknown. In this study, we analysed variation in sperm morphology among morphologically distinct and geographically isolated bluethroat subspecies in Europe. Consistent with previous studies, our analyses of mtDNA and nuclear introns suggest recent divergence and lack of lineage sorting among the subspecies. We found significant divergence in total sperm length and in the length of some sperm components (i.e. head and midpiece). There was a significantly positive relationship between pairwise divergences in sperm morphology and mitochondrial DNA, suggesting a role for genetic drift in sperm divergence. The magnitude of sperm length divergence was considerably higher than that in other geographically structured passerines, and even higher than that observed between several pairs of sister species. We hypothesize that the rapid sperm evolution in bluethroats is driven by sperm competition, and that strong postcopulatory sexual selection on sperm traits can lead to rapid speciation through reproductive incompatibilities. 相似文献
946.
947.
Michler SP Nicolaus M Ubels R van der Velde M Komdeur J Both C Tinbergen JM 《Behavioral ecology and sociobiology》2011,65(10):1975-1986
An individual’s decision to disperse from the natal habitat can affect its future fitness prospects. Especially in species
with sex-biased dispersal, we expect the cost–benefit balance for dispersal to vary according to the social environment (e.g.,
local sex ratio and density). However, little is known about the social factors affecting dispersal decisions and about the
temporal and spatial patterns of the dispersal process. In our study, we investigated experimentally the effects of the social
environment on post-fledging dispersal of juvenile great tits by simultaneously manipulating the density and sex ratio of
fledglings within forest plots. We expected young females in the post-fledging period mainly to compete for resources related
to food and, as they are subordinate to males, we predicted higher female dispersal from male-biased plots. Juvenile males
compete for vacant territories already in late summer and autumn; thus, we predicted increased male dispersal from high density
and male-biased plots. We found that juvenile females had a higher probability to leave male-biased plots and had dispersed
further from male-biased plots in the later post-fledging phase when juvenile males start to become territorial and more aggressive.
Juvenile males were least likely to leave male-biased plots and had smallest dispersal distances from female-biased plots
early after fledging. The results suggest that the social environment differentially affected the costs and benefits of philopatry
for male and female juveniles. The local sex ratio of individuals is thus an important social trait to be considered for understanding
sex-specific dispersal processes. 相似文献
948.
We exposed flour beetles (Tribolium castaneum) to a mixture of four poly aromatic hydrocarbons (PAHs). The experimental setup was chosen such that the emphasis was on assessing partial effects. We interpreted the effects of the mixture by a process-based model, with a threshold concentration for effects on survival. The behavior of the threshold concentration was one of the key features of this research. We showed that the threshold concentration is shared by toxicants with the same mode of action, which gives a mechanistic explanation for the observation that toxic effects in mixtures may occur in concentration ranges where the individual components do not show effects. Our approach gives reliable predictions of partial effects on survival and allows for a reduction of experimental effort in assessing effects of mixtures, extrapolations to other mixtures, other points in time, or in a wider perspective to other organisms. 相似文献
949.
Terje Laskemoen Oddmund Kleven Frode Fossøy Raleigh J. Robertson Geir Rudolfsen Jan T. Lifjeld 《Behavioral ecology and sociobiology》2010,64(9):1473-1483
Sperm competition is widespread among animal taxa and considered a major force in sperm evolution. Recent comparative studies have indicated that sperm competition selects for high sperm production capacity and long and fast-swimming spermatozoa across species. Here, we examine the role of sperm quantity and quality for fertilization success of individual males in a Canadian population of tree swallows Tachycineta bicolor, a socially monogamous, but highly promiscuous passerine. Male fertilization success (the sum of withinpair and extrapair young) was significantly associated with the size of the cloacal protuberance (a proxy for sperm quantity), but not with sperm size or in vitro sperm swimming speed. In a multivariate analysis, both cloacal protuberance volume and relative sperm midpiece size (i.e. high mitochondrial loading) had significant effects on male fertilization success. However, relative sperm midpiece size was not associated with fertilization success in a simple regression. Further, both cloacal protuberance volume and relative midpiece size had significant effects on sperm velocity, both in simple regressions and in a multivariate analysis. The finding that males with large relative midpiece size had both higher fertilization success and faster swimming sperm, suggests an indirect link between sperm morphology and male fertility mediated through sperm velocity. In conclusion, both quantitative and qualitative sperm traits seem to affect male fertilization success in tree swallows. 相似文献
950.
First evidence for a stereoselective incorporation of nonylphenol diastereomers in soil-derived organo-clay complexes 总被引:1,自引:1,他引:0
Riefer Patrick Schwarzbauer Jan Schäffer Andreas Klausmeyer Timm Schmidt Burkhard 《Environmental Chemistry Letters》2011,9(2):293-299
Environmental processes can affect the stereochemical properties of organic pollutants. In particular, biotic processes like microbial transformations or membrane penetration alter the ratios of enantiomers as well as diastereomers. These effects have been intensively used not only in environmental studies but also in medicine, toxicology, pharmacy, and agricultural sciences. However, in order to identify unambiguously biotic-initiated alteration of organic compounds, the knowledge on the stereoselective effect of all relevant processes is mandatory. Therefore, here we report the first evidence for a stereospecific formation of non-extractable residues of a xeniobiotic in a highly relevant soil subfraction, the organo-clay complexes. In this study, soils were spiked with labeled and unlabeled nonylphenol isomer, and incubation experiments were performed to study its long-term incorporation behavior into soil-derived organo-clay complexes under abiotic and biotic conditions. Besides the extractable particle-associated proportion especially the humic fractions comprising the bound residues have been analyzed by GC/MS. Our results from biotic experiments revealed alterations of the diastereomeric composition of the contaminant in the different soil humic subfractions. A depletion of the first eluting diastereomer as expressed by diastereomeric ratios around 0.6 has been observed for the extractable fraction, whereas the non-extractable proportion was enriched in the first diastereomer (diasteremoric ratio around 1.0). On the contrary, the diastereomeric ratios remained unaffected during the abiotic experiments (diasteremoric ratio around 0.8). These systematic observations give clear evidence that the process of microbial-assisted incorporation of nonylphenol into soil organo-clay complexes is a stereoselective process. To our knowledge, this is the first report on a stereoselective incorporation process of organic substances forming non-extractable residues. Consequently, the formation of non-extractable residues has to be considered in environmental studies dealing with stereoselective analysis of organic pollutants in soils to study their microbial transformation. 相似文献