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101.
102.
George McGillivray Jill A Rosenfeld R. J. McKinlay Gardner Lynn H. Gillam 《黑龙江环境通报》2012,32(4):389-395
Molecular karyotyping using chromosome microarray analysis (CMA) detects more pathogenic chromosomal anomalies than classical karyotyping, making CMA likely to become a first tier test for prenatal diagnosis. Detecting copy number variants of uncertain clinical significance raises ethical considerations. We consider the risk of harm to a woman or her fetus following the detection of a copy number variant of uncertain significance, whether it is ethically justifiable to withhold any test result information from a woman, what constitutes an ‘informed choice’ when women are offered CMA in pregnancy and whether clinicians are morally responsible for ‘unnecessary’ termination of pregnancy. Although we are cognisant of the distress associated with uncertain prenatal results, we argue in favour of the autonomy of women and their right to information from genome-wide CMA in order to make informed choices about their pregnancies. We propose that information material to a woman's decision-making process, including uncertain information, should not be withheld, and that it would be paternalistic for clinicians to try to take responsibility for women's decisions to terminate pregnancies. Non-directive pre-test and post-test genetic counselling is central to the delivery of these ethical objectives. © 2012 John Wiley & Sons, Ltd. 相似文献
103.
The extent to which marine populations are “open” (panmixia) or “closed” (self-recruitment) remains a matter of much debate, with recent reports of high levels of genetic differentiation and self-recruitment among populations of numerous species separated by short geographic. However, the interpretation of patterns of gene flow (connectivity) is often based on a stepping stone model of dispersal that can genetically homogenise even distant populations and blur genetic patterns that may better reflect realised dispersal. One way in which realised long-distance dispersal can be accurately determined is by examination of gene flow of taxa between isolated archipelagos and a mainland where there is no possible stepping stone dispersal across the open ocean. We investigated the genetic structuring of populations of the intertidal gastropod Nerita melanotragus from the subtropical Kermadec Islands and temperate New Zealand’s North Island (the mainland), separated by 750 km of open ocean and characterised by contrasting environmental conditions. Analyses of seven microsatellite markers revealed an absence of genetic structuring with low F ST and Jost’s D values (from 0.000 to 0.007 and from 0.000 to 0.015, respectively) over large geographic distances and no evidence of isolation by distance among all populations. These results indicate that the realised dispersal of N. melanotragus is of at least 750 km, this species exhibits a very “open” form of connectivity and its larvae exhibit sufficient phenotypic plasticity to settle successfully in different environmental conditions, ranging from subtropical to cool temperate. 相似文献
104.
James Nelson Rachel Wilson Felicia Coleman Christopher Koenig Doug DeVries Chris Gardner Jeff Chanton 《Marine Biology》2012,159(2):365-372
Seagrass meadows are among the most productive ecosystems in the marine environment. It has been speculated that much of this
production is exported to adjacent ecosystems via the movements of organisms. Our study utilized stable isotopes to track
seagrass-derived production into offshore food webs in the northeastern Gulf of Mexico. We found that gag grouper (Myctereoperca microlepis) on reefs as far as 90 km from the seagrass beds incorporate a significant portion of seagrass-derived biomass. The muscle
tissue of gag grouper, a major fisheries species, was composed on average of 18.5–25% seagrass habitat-derived biomass. The
timing of this annual seagrass subsidy appears to be important in fueling gag grouper egg production. The δ34S values of gag grouper gonad tissues varied seasonally and were δ34S depleted during the spawning season indicating that gag utilize the seagrass-derived biomass to support reproduction. If
such large scale trophic subsidies are typical of temperate seagrass systems, then loss of seagrass production or habitat
would result in a direct loss of offshore fisheries productivity. 相似文献
105.
Accurate fecundity estimates are central to population modelling of reproductive status and egg production in a fishery. Southern
rock lobster (Jasus edwardsii) fisheries are managed with the consideration of performance measures based on the level of current egg production relative
to the unfished stock. Egg production is a function of the size at the onset of maturity, the size structure of the stock,
and the fecundity at length of lobsters. Fecundity at length of the Tasmania stock of J. edwardsii has not been reported previously and was estimated from seven sites around Tasmania. Data were analysed by classical linear
regression and also generalised linear models (GLM) with gamma and Poisson distributions. GLM with a gamma distribution produced
the best fit and did not require a correction factor to generate a model on the linear scale. Individual fecundity ranged
from 43,918 to 660,156 and could be predicted from carapace length according to the equation F = −1.707 + 2.969 (log length). The coefficient of length approximated three, implying the fecundity at length relationship
is cuboidal. Despite the spatial heterogeneity in reproductive parameters in this fishery, the inclusion of spatial information
and egg development stage into the analysis only explained an additional 1% of the variance in fecundity. Thus, it appears
valid to apply the relationship across the fishery without spatial separation. 相似文献
106.
Aging and demographic plasticity in response to experimental age structures in honeybees (<Emphasis Type="Italic">Apis mellifera</Emphasis> L) 总被引:1,自引:0,他引:1
Rueppell O Linford R Gardner P Coleman J Fine K 《Behavioral ecology and sociobiology》2008,62(10):1621-1631
Honeybee colonies are highly integrated functional units characterized by a pronounced division of labor. Division of labor
among workers is mainly age-based, with younger individuals focusing on in-hive tasks and older workers performing the more
hazardous foraging activities. Thus, experimental disruption of the age composition of the worker hive population is expected
to have profound consequences for colony function. Adaptive demography theory predicts that the natural hive age composition
represents a colony-level adaptation and thus results in optimal hive performance. Alternatively, the hive age composition
may be an epiphenomenon, resulting from individual life history optimization. We addressed these predictions by comparing
individual worker longevity and brood production in hives that were composed of a single-age cohort, two distinct age cohorts,
and hives that had a continuous, natural age distribution. Four experimental replicates showed that colonies with a natural
age composition did not consistently have a higher life expectancy and/or brood production than the single-cohort or double-cohort
hives. Instead, a complex interplay of age structure, environmental conditions, colony size, brood production, and individual
mortality emerged. A general tradeoff between worker life expectancy and colony productivity was apparent, and the transition
from in-hive tasks to foraging was the most significant predictor of worker lifespan irrespective of the colony age structure.
We conclude that the natural age structure of honeybee hives is not a colony-level adaptation. Furthermore, our results show
that honeybees exhibit pronounced demographic plasticity in addition to behavioral plasticity to react to demographic disturbances
of their societies. 相似文献
107.
Susan Clement Wilson Marleen Susman Sharon Bain Monica Wohlferd Daniel L. Van Dyke Art Daniel Beverly White R. J. McKinlay Gardner 《黑龙江环境通报》2002,22(8):681-685
We present six cases of 47,+i(5p)/46 mosaicism diagnosed at chorionic villus sampling (CVS), this being the first prospective series to be reported. The clinical indication in each was advanced maternal age. Further prenatal studies in four (amniocentesis, plus fetal blood sampling in one) did not show the isochromosome. In one case, subsequent amniocentesis showed 1/48 in situ colonies with the isochromosome, but fetal blood was karyotypically normal. These five pregnancies resulted in phenotypically normal livebirths; further normal follow-up reports (from age 4 months through 4 years) are noted in four of these. Analysis of placental tissue in one case confirmed the presence of the i(5p) mosaicism. In the remaining case, in which 100% of CVS cultured cells had the i(5p), the pregnancy was terminated. Fetal skin fibroblasts did not show the i(5p). Thus, in none of these six cases was true fetal mosaicism detected, nor an abnormal phenotype noted. We suggest that a 47,+i(5p)/46 karyotype, detected at CVS, may frequently reflect confined placental mosaicism. In addition, we report a case of the primary diagnosis of 47,+i(5p)/46 mosaicism at amniocentesis. The infant appeared normal at birth, but a brain malformation was subsequently identified. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
108.
Ingrid E. van Putten Sarah Jennings Stewart Frusher Caleb Gardner Marcus Haward Alistair J. Hobday Melissa Nursey-Bray Gretta Pecl André Punt Hilary Revill 《Regional Environmental Change》2013,13(6):1313-1323
Climate change will impact on ecological, social, and economic elements of fisheries; however, the three are seldom considered in an integrated fashion. We develop a fishery-level assessment of economic resilience to climate change for the Tasmanian rock lobster fishery, a linked social–ecological system. We outline the main climate change forcing influences that link climate change to the fishery via changes in lobster abundance, distribution, and phenology. Using a bottom-up approach, we identify twelve economic attributes strongly related to the fisheries’ economic resilience to climate change. Resilience attributes are grouped according to the level of the economic domain (business, sectoral, and governance). Attributes are then evaluated to determine the overall economic resilience of the rock lobster fishery in the context of the specific nature of predicted climate change effects. We identify areas of low resilience in the economic sub-system for this fishery. Evaluating the economic resilience of regional fisheries using this integrated, interdisciplinary framework provides a practical, parsimonious, and conceptually sound basis for undertaking comprehensive and contextually tailored assessments of climate change impacts and economic vulnerability. The framework can be extended to include a broader range of climate change impacts and the social domain of the human sub-system. 相似文献