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排序方式: 共有126条查询结果,搜索用时 156 毫秒
51.
Valerio Matozzo Marta Monari Jurgen Foschi Gian Paolo Serrazanetti Otello Cattani Maria Gabriella Marin 《Marine Biology》2007,151(3):1051-1058
In the present study, the effects of differing salinities on some important functional responses of haemocytes from the clam,
Chamelea gallina, were investigated. The animals were kept for 7 days at 28‰ (hyposalinity), 34‰ (control) and 40‰ salinity (hypersalinity),
and total haemocyte count (THC), haemocyte volume, phagocytosis, lysozyme-like activity (in both haemocyte lysate and cell-free
haemolymph) were measured. The survival-in-air test was also performed. Clams kept at 28‰ showed significantly increased THC
with respect to animals kept at 34 and 40‰. The analysis of haemocyte size frequency distribution highlighted that in clams
kept at 28‰ the haemocyte fraction of about 5 μm in diameter and 50–100 femtolitre in volume increased markedly. Conversely,
in animals kept at 40‰ an increase was observed in the haemocyte fraction having about 8–10 μm diameter and 400–500 femtolitre
volume. Higher phagocytic activity was recorded in haemocytes from control clams, with respect to that of clams kept at 28
and 34‰. Lysozyme-like activity in haemocyte lysate was shown to increase significantly in animals kept at 28‰ with respect
to that of clams kept at 40‰, whereas enzyme activity in cell-free haemolymph from clams kept at 34‰ was significantly higher
with respect to that of clams maintained at 40‰. A relationship between phagocytosis and lysozyme secretion is suggested.
The resistance to air exposure of clams kept at 28 and 40‰ was shown to decrease significantly; LT50 values fell from 7 days in clams kept at 34‰ to 4 and 5 days in those kept at 28 and 40‰, respectively. Results demonstrated
that salinity values far from 34‰ affects the functional responses of haemocytes and reduce the resistance of clams to exposure
to air. 相似文献
52.
Marin Lysák Christian Bugge-Henriksen 《Mitigation and Adaptation Strategies for Global Change》2016,21(3):323-342
The objective of the analysis is to compare the current status of state level climate change adaptation plans across the United States (U.S.) and to analyze potential factors that may influence their status. Based on their most current adaptation planning documentation individual states are grouped into four categories depending on how far they are in their approach towards adaptation to predicted changes in climate and how they have progressed with their planning efforts in defining adaptation measures. The analysis of the state adaptation plans showed that 13 states had detailed sector specific actions recommended, 2 states had sector specific targets and recommendation, 14 states had expressed concern and need for adaptation planning, whereas 21 states did not mention the need for adaptation planning. The statistical analysis showed that Democratic Party popular votes are 10 % higher in states with detailed sector specific actions recommended in comparison to states with no mention of adaptation planning (p?<?0.01). The average gross domestic product (GDP) per capita in states having an adaptation planning status with detailed sector specific actions recommended is more than $6,000 higher compared to states with expressed concern and need for adaptation planning and states with no mention of adaptation planning (p?<?0.05). The average coastal population in states with detailed sector specific actions recommended is more than seven times higher compared to states with expressed concern and states with no mention of adaptation planning (p?<?0.01). It is concluded that the U.S. state planning initiatives will need to strengthen their approach to adaptation planning substantially to have holistic and more coordinated adaptation planning efforts. 相似文献
53.
In the context of environmental change projections at the regional level, not only the climate but also the land use plays
a key role. The limited availability of historical information reduces the possibility to calibrate land use change (LUC)
models. Even in case of successful calibration, using it both for diagnostic and prognostic studies does not guarantee the
reliability of single future simulations. Through ensemble forecasting, useful LUC predictions are evaluable. In this work,
after introducing a modified version of the well-assessed CLUE-S model, we present reasonable hot-spots of LUC in Italy for
the end of 21st century, derived from the agreement of a 32 simulation ensemble performed alternating two choices for five
model configurations or inputs: (1) two different climate projections (reflecting A2 and B2 emission scenarios by IPCC, respectively);
(2) two different degrees (slight and strong) of demographic increase; (3) the conservation (or not) of protected areas; (4)
the influence (or not) among adjacent land uses in determining their shift; and (5) the importance (or not) of past/recent
LUC trends. Results, in terms of LUC hot-spot distribution, were evaluated at administrative, biogeographical, physiographic,
and watershed level. The main findings highlighted that some trends of land use substitution will be likely opposite to the
past and that a more detailed spatial scale can detect situations neglected by coarser scale evaluations, and due to different
transpositions of directives from high-levels to local scales. Biogeographical and physiographic settings seem strongly influencing
LUCs, and administrative and catchment units across Italy show very different developments and a highly fragmented territory
in terms of LUC hot-spots, all that to be considered in landscape and resource planning. 相似文献
54.
Variation of bilateral leaf structures in Middle Ural cenopopulations of the weeping birch (Betula pendula Roth.) growing in gradients of industrial pollution was studied to test the efficiency of a new method of population and
individual phenogenetic monitoring allowing an indirect assessment of developmental destabilization by segregating the variance
of total asymmetry (TA
R
2) into its additive components, the variances of fluctuating asymmetry (FA
R
2) and directional asymmetry (DA
R
2). The method was tested in the impact zones of two copper-smelting plants in the Middle Urals. The degree of impact was characterized
by the index of technogenic pollution (ITP) reflecting the average total contents of 15 water-soluble pollutants in snow samples. The level of asymmetry was estimated
from the numbers of denticles with incoming veins (dentovenal elements) on the left and right leaf margins. Spearman’s coefficient
of rank correlation between the group values of variance in fluctuating asymmetry (FA
R
2) and corresponding ITP values reached r
S = 0.914 (p < 0.001), providing evidence that the method is highly appropriate for ecological indication of the phenogenetic response
of trees to environmental pollution. 相似文献
55.
56.
Silvana Salerno Riccardo Tartaglia Sauro Garzi Andrea Biagioni Giovanni Rulli Bruno Maggi 《International journal of occupational safety and ergonomics》2013,19(1):97-106
The aim of this research is the application of the Method of Organizational Congruencies before and after the substitution of organic solvents with vegetable agents for the cleaning of an offset printing machine in order to assess the organizational changes. A solvent-free process is the goal of the Subsprint Project (Technology Transfer Program of the European Community). This, study shows how human and environmental health is improved by using vegetable agents, though this change may lead to some other organizational constraints such as an increase of tbe time needed, monotony, and repetitiveness of the technical actions involved. The authors underline that the knowledge of the impact of the new technology on health helps a better understanding of the resistance to the change and its further amelioration. 相似文献
57.
58.
Simone Bastianoni Fabiana MorandiTommaso Flaminio Riccardo M. PulselliElisa B.P. Tiezzi 《Ecological modelling》2011,222(16):2903-2907
Emergy is an important concept that has originated several effects in ecology, systems ecology and sustainability science. Its communication, however, has always presented several problems, since it does not follow the same rules of conservation as other energy-based approaches. Attempts have been made to clarify emergy by means of more formal/mathematical approaches, but the problem persists. In this paper, we have introduced a view of emergy and of its algebra based on ingenuous set theory. By means of this simple tool, emergy can be defined as the set of solar exergy that is directly and indirectly necessary to make a product. The operation that correctly sums the emergy “carried” by the inputs to a process is the union. This definition and the operation of union are able to account for all the rules of emergy algebra. 相似文献
59.
The relationship between agricultural intensification and biological control: experimental tests across Europe 总被引:2,自引:0,他引:2
Thies C Haenke S Scherber C Bengtsson J Bommarco R Clement LW Ceryngier P Dennis C Emmerson M Gagic V Hawro V Liira J Weisser WW Winqvist C Tscharntke T 《Ecological applications》2011,21(6):2187-2196
Agricultural intensification can affect biodiversity and related ecosystem services such as biological control, but large-scale experimental evidence is missing. We examined aphid pest populations in cereal fields under experimentally reduced densities of (1) ground-dwelling predators (-G), (2) vegetation-dwelling predators and parasitoids (-V), (3) a combination of (1) and (2) (-G-V), compared with open-fields (control), in contrasting landscapes with low vs. high levels of agricultural intensification (AI), and in five European regions. Aphid populations were 28%, 97%, and 199% higher in -G, -V, and -G-V treatments, respectively, compared to the open fields, indicating synergistic effects of both natural-enemy groups. Enhanced parasitoid: host and predator: prey ratios were related to reduced aphid population density and population growth. The relative importance of parasitoids and vegetation-dwelling predators greatly differed among European regions, and agricultural intensification affected biological control and aphid density only in some regions. This shows a changing role of species group identity in diverse enemy communities and a need to consider region-specific landscape management. 相似文献
60.
For the first time, gender-related differences in some important functional parameters of haemocytes from the clam Ruditapes philippinarum have been studied. Clams were collected during the pre-spawning phase, when sex can be distinguished by microscopic observation
of gonadal smears, in order to ascertain whether the two sexes reach the stressful spawning period with different degrees
of immunosurveillance. Total haemocyte count (THC), haemocyte size frequency distribution, capability of haemocytes to assume
the vital dye neutral red (NR, indicative of endocytotic activity), lysozyme-like and acid phosphatase activities in both
haemocyte lysate (HL) and cell-free haemolymph (CFH), and superoxide dismutase (SOD) and catalase (CAT) activities in HL were
all evaluated. No differences in THC values were found between the two sexes, but differing haemocyte size frequency distributions
were observed: the fraction of larger haemocytes (7–9 μm diameter, 200 fl volume) was markedly increased in females and that
of smaller haemocytes (<5 μm diameter, <200 fl volume) markedly increased in males. Interestingly, when haemocytes were observed
under the light microscope, a significantly higher percentage of granulocytes was found in haemolymph from females, compared
with that of males. Significantly increased NR uptake was recorded in female haemocytes. No significant variation in lysozyme-like
activity was observed in HL, whereas in CFH, enzyme activity was significantly higher in females. HL acid phosphatase activity
was significantly higher in males with respect to females; no significant variations in enzyme activity were observed in CFH.
HL SOD and CAT activities were significantly higher in females than in males. Overall, on the basis of the cell parameters
studied here, gender-related differences in immune parameters were found in R. philippinarum, indicating that females have more active haemocytes than males during the pre-spawning period. 相似文献