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11.
The Red Data Book of Japanese Vascular Plants is based on their risk of extinction. In order to construct the list, 2000 taxa were evaluated using population data and rates of decline for approximately 4400 grids, each of approximately 100 km(2). This database can be used to estimate the impact of human activity on a threatened plant's risk of extinction. In order to evaluate extinction risks and apply the evaluation to conservation actions, the discount mean time to extinction is defined as a measure of extinction risk, where the present value of a species' persistence in the future decreases exponentially. The rate of decrease has to be much less than the rate of economic discounting, in order to realize intergenerational sustainability. Increases of the inverse, and logarithm, of the discount mean time to extinction are considered measures of the extinction risk. We applied these measures to an environmental impact assessment for the Japanese World Exposition that is to be held in 2005. Development will have a greater impact on threatened Salvia species than it will on star magnolia, Magnolia tomentosa, which has been conserved by changing the site plan. 相似文献
12.
Integrated measures for preservation, restoration and improvement of the environmental conditions of the Lagoon Olho d'Agua basin 总被引:1,自引:0,他引:1
The Lagoon Olho d'Agua in Pernambuco State, Northeast Brazil has received increasing environmental concern due to significant stress from pollution in the catchment. The existing environmental problems are the result of great pressure from a broad range of human activities, especially in the last 10 years. Serious pollution exists mainly from some industrial and urban activities, which increased intensively after the eighties. There is a strong social and economical pressure for housing and construction near the lagoon, due to the available land nearby beaches and estuarine zone, and recently by growing tourism activities. Uncontrolled land use by low-income communities and the pressure for construction by developers have led to landfilling and to deterioration of water quality in the lagoon catchment. Improvement of the environmental conditions in the catchment needs integrated measures. Guidelines and some specific actions involving several institutions have been established and refer to sanitation and urban infrastructure as the main priorities. A main target is the construction of low-cost sewage system with smaller and decentralised treatment plants. 相似文献
13.
Nizar El-Murr Marie-Christine Maurel Martina Rihova Jacques Vergne Guy Hervé Mikio Kato Kunio Kawamura 《Die Naturwissenschaften》2012,99(9):731-738
The “RNA world” hypothesis proposes that—early in the evolution of life—RNA molecules played important roles both in information storage and in enzymatic functions. However, this hypothesis seems to be inconsistent with the concept that life may have emerged under hydrothermal conditions since RNA molecules are considered to be labile under such extreme conditions. Presently, the possibility that the last common ancestor of the present organisms was a hyperthermophilic organism which is important to support the hypothesis of the hydrothermal origin of life has been subject of strong discussions. Consequently, it is of importance to study the behavior of RNA molecules under hydrothermal conditions from the viewpoints of stability, catalytic functions, and storage of genetic information of RNA molecules and determination of the upper limit of temperature where life could have emerged. In the present work, self-cleavage of a natural hammerhead ribozyme was examined at temperatures 10–200?°C. Self-cleavage was investigated in the presence of Mg2+, which facilitates and accelerates this reaction. Self-cleavage of the hammerhead ribozyme was clearly observed at temperatures up to 60?°C, but at higher temperatures self-cleavage occurs together with hydrolysis and with increasing temperature hydrolysis becomes dominant. The influence of the amount of Mg2+ on the reaction rate was also investigated. In addition, we discovered that the reaction proceeds in the presence of high concentrations of monovalent cations (Na+ or K+), although very slowly. Furthermore, at high temperatures (above 60?°C), monovalent cations protect the ribozyme against degradation. 相似文献
14.
Daisuke Kitazawa Shigeru Tabeta Masataka Fujino Takayoshi Kato 《Environmental monitoring and assessment》2010,165(1-4):461-474
To assess the environmental impacts of large floating structures, various physical, chemical, and biological parameters were measured. The current and water quality were monitored around a prototype floating structure called the Phase-II Mega-Float model (MF-II model), which was moored off Yokosuka in Tokyo Bay during the period 1999–2000. The effects of the MF-II model on the condition of the physical environment, e.g., the direction and flow rate of water currents and the stratification structure, were negligible. Analysis of water quality showed that the concentrations of chlorophyll a and nutrients only varied just below the MF-II model. However, such variations were localized to within 5 m below the MF-II model since the waters were exchanged because of the tidal current. The minor changes in water quality are attributable to the impedance of photosynthesis due to the sea-covering effect and the activities of sessile organisms fouling the bottom surface of the MF-II model. 相似文献
15.
Jiro Kato 《Die Naturwissenschaften》1963,50(6):226-226
16.
Katsumi Naoya Miyake Shuhei Okochi Hiroshi Minami Yukiya Kobayashi Hiroshi Kato Shungo Wada Ryuichi Takeuchi Masaki Toda Kei Miura Kazuhiko 《Environmental Chemistry Letters》2019,17(2):1023-1029
Environmental Chemistry Letters - The abundance of humic-like substances in the atmosphere has received considerable attention since these substances play an important role in various atmospheric... 相似文献
17.
18.
André Chiaradia Yan Ropert-Coudert Akiko Kato Thomas Mattern Julija Yorke 《Marine Biology》2007,151(4):1535-1542
Little Penguins, Eudyptula minor, breed in several small colonies in New Zealand and Australia. In this study, we compare the birds’ diving performances at
different sites situated throughout their breeding range. Environmental conditions and breeding success vary drastically amongst
colonies, but all birds feed on similar types of prey and face similar limitations on their foraging range. We examined several
diving parameters and calculated the proportion of foraging zone available during breeding to examine whether oceanographic
and geographic factors in the foraging zone can explain variations in diving behaviour and fledging success among the different
colonies. In colonies with high fledging success, Penguin Island and Oamaru, penguins made shallow dives <50 m depth and had
lower diving effort. More than 90% of the foraging zone was in waters <50 m depth in these colonies. Motuara Island also has
shallow waters with 95% <50 m depth, but the fledging success was low. Phillip Island has only 42% of waters <50 m and comparatively
low fledging success. Thus, penguins dived deeper and showed a higher diving effort in colonies with lower fledging success
(Motuara Island and Phillip Island), indicating that they were disadvantaged compared to conspecifics from other colonies
that dived shallower and with a lesser diving effort. We concluded that bathymetry is an important factor, but not the only
one, which influences fledging success. 相似文献
19.
Information about foraging speeds is particularly valuable when the impact of a predator species upon a community of prey has to be defined, as in the case of great cormorants. We measured the swim speed of 12 (six males and six females) free-ranging great cormorants Phalacrocorax carbo, foraging off the Greenland coast during the summer of 2003, using miniaturized data-loggers. Although mean body mass of males was 27% greater than that of females, and mean swim speed of males were 29–57% higher than that of females during foraging phases (but not descent phases) of dives, these differences in speeds were not significant due to high variances. Birds descended to the mean maximum depth of 4.7 m at an average speed of 1.6±0.5 m s−1, a speed similar to that measured in captive cormorants in previous studies. Although bursts of up to 4 m s−1 were recorded, speed usually decreased during the deepest (foraging) phase of dives, being on average 0.8±0.6 m s−1. Speeds measured here should be taken with caution, because the large propeller loggers used to measure speed directly decreased descent speeds by up to 0.5 m s−1 when compared to smaller depth-only loggers. Cormorants in Greenland seem to combine two searching strategies, one requiring low speed to scan the water column or benthos, and one requiring high speed to pursue prey. These two strategies depend on the two main habitats of their prey: pelagic or demersal. 相似文献
20.
Reductive dechlorination of non-ortho substituted polychlorinated biphenyls by ultraviolet irradiation in alkaline 2-propanol 总被引:3,自引:0,他引:3
Yuan Yao Kohji Kakimoto Hiroaki I. Ogawa Yasuhiko Kato Yoshifumi Hanada Ryota Shinohara Eiichi Yoshino 《Chemosphere》1997,35(12):2891-2897
The photodechlorination pathways of 3,3′,4,5,5′-pentachlorobiphenyl (3,3′,4,5,5′-PentaCB) and the related lower polychlorinated biphenyl congeners irradiated at 254 nm in alkaline 2-propanol were elucidated. Steric effect is the most important factor for controlling the dechlorination pattern of these substrates. Electronic effect also influences the photoreactivity of chlorine substituents. 相似文献