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171.
Restoring riparian ecosystems in human-dominated landscapes requires attention to complexity, and consideration of diverse drivers, social actors, and contexts. Addressing a Global North bias, this case study uses a mixed-method approach, integrating historical data, remote sensing techniques and stakeholder perceptions to guide restoration of a river in the Western Cape, South Africa. An analysis of aerial photographs of the riparian zone from 1953 to 2016 revealed that although anthropogenic land conversion happened primarily before the 1950s, several land use and land cover classes showed marked increases in area, including: waterbodies (+ 1074%), urban areas (+ 316%), alien weeds (+ 311%) and terrestrial alien trees (+ 79%). These changes have likely been driven by land fragmentation, disturbance, and agricultural intensification. Stakeholder interviews revealed that despite the clear need for restoration, several barriers exist to successful implementation; these stem from inadequate financial resources, inappropriate funding models, institutional challenges, and a lack of techno-scientific knowledge. We give several recommendations to overcome these barriers.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01691-y. 相似文献
172.
Bert Hölldobler Malu Obermayer Nicola J. R. Plowes Brian L. Fisher 《Die Naturwissenschaften》2014,101(7):527-532
Fisher and Robertson (Insect Soc 46: 78–83, 1999) discovered the production of silk-like secretions emerging from slit-shaped openings along the anterior margin of the ventral hypostoma of Melissotarsus ant workers. The current histological study describes a hitherto unknown hypostomal gland from which this silk-like substance originates. In addition, this study describes a new basitarsal gland in the three pairs of legs of Melissotarsus workers. 相似文献
173.
La Rocca C Alivernini S Badiali M Cornoldi A Iacovella N Silvestroni L Spera G Turrio-Baldassarri L 《Chemosphere》2008,73(1):92-96
Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), mono-ortho and non-ortho polychlorinated biphenyls (dioxin-like PCBs) were determined in samples of human fat tissue from nine Italian obese patients. The toxicity equivalent (TEQ) values ranged from 9 to 25pgTEQg(-1) lipid (WHO-TEF values, 2005 [Van den Berg, M., Birnbaum, L.S., Denison, M., De Vito, M., Farland, W., Feeley, M., Fiedler, H., Hakansson, H., Hanberg, A., Haws, L., Rose, M., Safe, S., Schrenk, D., Tohyama, C., Tritscher, A., Tuomisto, J., Tysklind, M., Walker, N., Peterson, R.E., 2006. The 2005 World Health Organization reevaluation of human and mammalian Toxic Equivalency Factors for dioxins and dioxin-like compounds. Toxicol. Sci. 93, 223-241]), the contribution of dioxin-like PCBs was more than 30% of the total TEQ values. The obese body burdens varied from 6 to 11ngTEQkg(-1) body weight (BW), exceeding the estimated steady-state body burden 5ngTEQkg(-1) BW, based on lipid adjusted serum concentrations from several populations in the mid-1990s, calculated in the risk assessment US EPA document. 相似文献
174.
Nicola Isendahl Art Dewulf Claudia Pahl-Wostl 《Journal of environmental management》2010,91(4):844-851
By now, the need for addressing uncertainty in the management of water resources is widely recognized, yet there is little expertise and experience how to effectively deal with uncertainty in practice. Uncertainties in water management practice so far are mostly dealt with intuitively or based on experience. That way decisions can be quickly taken but analytic processes of deliberate reasoning are bypassed. To meet the desire of practitioners for better guidance and tools how to deal with uncertainty more practice-oriented systematic approaches are needed. For that purpose we consider it important to understand how practitioners frame uncertainties. In this paper we present an approach where water managers developed criteria of relevance to understand and address uncertainties. The empirical research took place in the Doñana region of the Guadalquivir estuary in southern Spain making use of the method of card sorting. Through the card sorting exercise a broad range of criteria to make sense of and describe uncertainties was produced by different subgroups, which were then merged into a shared list of criteria. That way framing differences were made explicit and communication on uncertainty and on framing differences was enhanced. In that, the present approach constitutes a first step to enabling reframing and overcoming framing differences, which are important features on the way to robust decision-making. Moreover, the elaborated criteria build a basis for the development of more structured approaches to deal with uncertainties in water management practice. 相似文献
175.
Nicola J. van Wilgen Núria Roura-Pascual David M. Richardson 《Environmental management》2009,44(3):590-607
Assessing climatic suitability provides a good preliminary estimate of the invasive potential of a species to inform risk
assessment. We examined two approaches for bioclimatic modeling for 67 reptile and amphibian species introduced to California
and Florida. First, we modeled the worldwide distribution of the biomes found in the introduced range to highlight similar
areas worldwide from which invaders might arise. Second, we modeled potentially suitable environments for species based on
climatic factors in their native ranges, using three sources of distribution data. Performance of the three datasets and both
approaches were compared for each species. Climate match was positively correlated with species establishment success (maximum
predicted suitability in the introduced range was more strongly correlated with establishment success than mean suitability).
Data assembled from the Global Amphibian Assessment through NatureServe provided the most accurate models for amphibians,
while ecoregion data compiled by the World Wide Fund for Nature yielded models which described reptile climatic suitability
better than available point-locality data. We present three methods of assigning a climate-match score for use in risk assessment
using both the mean and maximum climatic suitabilities. Managers may choose to use different methods depending on the stringency
of the assessment and the available data, facilitating higher resolution and accuracy for herpetofaunal risk assessment. Climate-matching
has inherent limitations and other factors pertaining to ecological interactions and life-history traits must also be considered
for thorough risk assessment.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
176.
Diego Rubolini Maria Romano Roberta Martinelli Nicola Saino 《Behavioral ecology and sociobiology》2006,59(3):344-352
Androgen hormones of maternal origin contained in the eggs of avian species are considered to have positive effects on offspring
characteristics and performance. However, negative consequences have also been reported, suggesting that mothers may experience
a trade-off between beneficial and detrimental effects of egg androgens to offspring fitness. We studied the effects of elevated
yolk testosterone (T) concentration on survival, development and phenotype of male and female yellow-legged gull (Larus michahellis) chicks by injecting egg yolks with physiological doses of the hormone. Elevated yolk T resulted in a male-biased post-hatching
sex ratio, T-treated clutches producing a greater proportion of males compared to control ones at day 4 post-hatching, likely
resulting from a reduction of female embryonic survival, whereas no effect of hormone treatment on hatching success or short-term
chick survival was observed. In addition, T depressed post-hatching body mass in both sexes but had no effects on the intensity
of the cell-mediated immune response or skeletal growth. No sex differences in egg characteristics or chick phenotype were
detected. Time to hatching was not affected by T, but females originating from first laid eggs hatched earlier than males
of the same laying order, independently of hormone treatment. However, the implications of sex differences in hatching times
are unclear in the study species. Taken together, our results suggest that female yellow-legged gulls may be constrained in
transferring androgens to their eggs by negative consequences on the viability of female offspring and growth of chicks of
the two sexes. 相似文献
177.
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180.
Glycosaminoglycans (GAGs) from the hemolymph of the freshwater snail Planorbarius corneus were recovered at about 0.9 μg/mL, being composed of a unique species characterized as chondroitin sulfate (CS) with a molecular
mass of approximately 31,000 and having glucuronic acid as hexuronic acid. This macromolecule was determined to be composed
of a low-sulfated polysaccharide made up of approximately 25% of the nonsulfated disaccharide, 17% of the 6-sulfated disaccharide,
and about 58% of the 4-sulfated disaccharide, with a charge density value of 0.75 and a 4-sulfated/6-sulfated ratio of approximately
3.4. The data obtained suggest that the CS recovered in the Planorbarius corneus hemolymph is similar to the main human plasma polysaccharide and it may be generated as a main product of the catabolic processes. 相似文献