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排序方式: 共有101条查询结果,搜索用时 31 毫秒
81.
82.
Joanna Paldyna Beata Krasnodebska-Ostrega Karolina Kregielewska Joanna Kowalska Lukasz Jedynak Jerzy Golimowski Tomasz Grobelski Jadwiga Farbiszewska-Kiczma Teresa Farbiszewska 《Environmental Earth Sciences》2013,68(2):439-450
Stored metallurgy and mining wastes contain relatively high amounts of potentially toxic elements. To monitor the distribution of contaminants originating from dumps, the chemical and physical properties of the wastes must be characterised. In this study, the chemical properties of wastes deposited in two different locations in Southern Poland (Szklary and Zloty Stok) were evaluated. Heaps located in Zloty Stok contain wastes from gold mineralisation comprising arsenic while wastes in Szklary originate from a factory that produced an iron-nickel alloy. In Szklary the total concentrations of Ca, Mg, Fe, Zn, Mn, Cr, Co, Cu, Ni, Tl, Ag, Cd and Pb were determined, while in Zloty Stok also As is an important contaminant. To assess the risk of contamination of the surrounding environment and to select the proper method for removing the contaminants, information on the distribution of elements between operationally defined phases must be obtained. For this purpose, a six-step sequential extraction was used. The mobility of most elements in the wastes from Szklary and Zloty Stok was relatively low; however, the large amount of As, 40–180 mg L?1, that could be released to environment in case of Zloty Stok was high. The results of fractionation studies indicated that Ag, Cd, Tl, Co, Cu, Cr, Pb, Zn and Mn may be released into environment under low pH and low redox potential conditions, which can be induced by bacterial activity. 相似文献
83.
We have used Yohkoh and GOES X-ray observations to investigate flares with a long rising phase. We have found that a characteristic feature of
such flares is a long time interval, Δ t ≥ 20 min, between the temperature maximum and the maximum of the emission measure. We have carried out detailed analysis
for 10 limb flares of this type. Time variation of the heating function, EH(t), has been determined for their loop-top X-ray kernels. The time variation of EH(t), together with the temperature–density diagnostic diagrams, have been used to explain the large value of the time interval,
Δ t. The main point is that for these flares the heating function EH(t) decreases so slowly after the temperature maximum, that for the long time, Δ t, the energy flux reaching flare foot points is sufficient to maintain significant chromospheric evaporation. Investigation
of the flare evolution in the temperature–density diagnostic diagrams allowed us to work out a new method of determination
of the density for flare kernels. This method can be applied to all the kernels for which their altitudes can be estimated.
The advantage of this method is that for the density determination it is not necessary to assume what is the extension of
the emitting plasma along the line of sight. 相似文献
84.
Leonard Boszke Artur Kowalski Aleksander Astel Andrzej Barański Barbara Gworek Jerzy Siepak 《Environmental Geology》2008,55(5):1075-1087
The mobility and bioavailability of mercury in the soil from the area near a plant using elemental mercury for manufacturing
thermometers, areometers, glass energy switches and other articles made of technical glass has been evaluated. Mercury has
been determined by sequential extraction method and with additional thermo desorption stage to determine elemental mercury.
The procedure of sequential extraction involves five subsequent stages performed with the solutions of chloroform, deionized
water, 0.5 M HCl, 0.2 M NaOH and aqua regia. The mean concentration of total mercury in soil was 147 ± 107 μg g−1 dry mass (range 62–393), and the fractionation revealed that mercury was mainly bound to sulfides 56 ± 8% (range 45–66),
one of the most biounavailable and immobile species of mercury in the environment. The fractions that brought lower contribution
to the total mercury content were semi-mobile humic matter 22 ± 9% (range 11–34) and elemental mercury 17 ± 5% (range 8–23).
The contributions brought by the highly mobile and toxic organomercury compounds were still lower 2.3 ± 2.7% (range 0.01–6.5).
The lowest contributions brought the acid-soluble mercury 1.5 ± 1.3% (range 0.1–3.5) and water-soluble mercury 1.0 ± 0.3%
(range 0.6–1.7). The surface layer of soil (0–20 cm) was characterized by higher mercury concentrations than that of the subsurface
soil (60–80 cm), but the fractional contributions were comparable. The comparison of mercury fractionation results obtained
in this study for highly polluted soils with results of fractionation of uncontaminated or moderately contaminated samples
of soil and sediments had not shown significant statistical differences; however, in the last samples elemental mercury is
usually present at very low concentrations. On the basis of obtained correlation coefficients it seems that elemental mercury
soils from “Areometer” plant are contaminated; the main transformation is its vaporization to atmosphere and oxidation to
divalent mercury, probably mainly mediated by organic matter, and next bound to humic matter and sulfides. 相似文献
85.
Smoothing soil surfaces, which had previously been deeply plowed, increases their albedo, which results in a lower amount of shortwave radiation being absorbed by their surface layer. Those surfaces emit less long-wave radiation too, leading to a reduction in their surface temperature, which can affect the climate. This paper quantitatively estimates the highest possible amount of shortwave radiation that could be reflected throughout the year from bare soils on arable land in the most extensive agricultural regions, where major crops are cultivated, on six of the Earth’s continents. The estimation refers to the highest levels of soil radiation occurring during clear-sky conditions without any clouds when the surfaces that had been conventionally tilled were bare for several days or more after the day of planting and were air-dried in two extreme roughness states: those formed by a plow and a smoothing harrow. The annual dynamics of reflective shortwave radiation of the bare soils were obtained using vectorized and rasterized geostatistical data sets about the areas of the soils and periods when they were bare, as well the spectra of the soil units that occupied the majority of these areas. Adding together all of the diurnal amounts of shortwave radiation reflected from the bare soils for each of the regions in the world, it was found that their radiation peak, appearing on the 140th days of the year, can reach about 22 EJ/day for soils treated by a plow, and a further 3 EJ/day when they are smoothed by a smoothing harrow. 相似文献
86.
Jean-Maurice Cases Jerzy Mielczarski Ella Mielczarska Laurent J. Michot Frédéric Villiéras Fabien Thomas 《Comptes Rendus Geoscience》2002,334(9):675-688
The adsorption of surfactants from aqueous solution is a phenomenon of major importance in applications ranging from ore flotation and paint technology to enhanced oil recovery. As this paper will illustrate, the process is very complex and of high scientific interest; its results can be extended to the retention of organic compounds (humic and fulvic acids, pollutants...) on solids in the biosphere. For a good understanding of the mechanisms involved in surfactants adsorption at the hydrophilic solid–aqueous solution interface, thermodynamic models have to take into account: (i) the physical chemistry of the surfactant in aqueous solution for choosing the appropriate reference phase, (ii) the surface heterogeneity of the adsorbing solid, (iii) the intensity of normal adsorbate–adsorbent bonds responsible for adsorption, (iv) the intensity of lateral bonds that favour the formation of surface aggregates through cooperative process and finally, (v) suitable theoretical models to describe adsorption phenomena. Once this has been achieved, two systems can be discussed: systems characterised by strong normal adsorbate–adsorbent bonds, currently used in ore flotation, which lead, in the case of heterogeneous surfaces, to the formation of lamellar aggregates at monolayer concentration and bilayer formation for higher concentrations. Systems characterised by weak normal adsorbate–adsorbent bonds, currently used in enhanced oil recovery and hydrocarbon (bio)remediation, which correspond to: (i) formation of globular micelles at the solid surface near the CMC when the temperature is higher than the Krafft point, (ii) formation of bilayered lamellar aggregates in the opposite case, (iii) three-dimensional condensation on substrate (T<TKrafft) if the ionic surfactant interacts with cations in the bulk. To cite this article: J.-M. Cases et al., C. R. Geoscience 334 (2002) 675–688. 相似文献
87.
Wiesław Wiśniewolski Jerzy Nabiałek 《Aquatic Sciences - Research Across Boundaries》1993,55(2):143-152
Fish survival, tag retention and tag loss were evaluated in pond experiments and described by linear regression equations. Tagging of fish had no significant influence on their survival. However, loss of tags caused strong differences between actual fish survival and the survival rate e–z estimated on recovered tags. Mathematical functions were derived to correct tag loss. Values of those functions depend upon the type of tag and time after tagging. The B-type of tagging, which approximated the Swedish Carlin method, appeared to be most effective. The rate of tag loss was independent of the fish species (common carp, tench) used in the experiments. 相似文献
88.
Acoustic emission and sorptive deformation induced in coals of various rank by the sorption-desorption of gas 总被引:1,自引:0,他引:1
Simultaneous measurements of acoustic emission (AE) and expansion/contraction of coal samples subjected to gas sorption-desorption
processes were conducted on high-and medium-rank coal. The aim of this study was to examine the influence of the coal rank
and type of sorbate on measured AE and strain characteristics.
The experimental equipment employed in this study consisted of a pressure vessel and associated pressurisation and monitoring
units. The arrangement of pressure-vacuum valves permitted the coal sample to be pressurised and depressurised. Carbon-dioxide
and methane were used as sorbats. 相似文献
89.
Sławomir Jerzy Gibowicz 《Acta Geophysica》2006,54(2):142-157
The following criteria for selection of doublets at Polish coal mines were accepted: the difference in magnitude (based on
seismic moment) of two events not larger than 0.15, the distance between their hypocenters not greater than 150 m, and the
time interval between their occurrence not longer than 10 days. Similarly, the criteria for seismic events at copper mines
are: the difference in magnitude not exceeding 0.15, the distance not greater than 200 m, and the time interval not longer
than 20 days. Seismic events from the Wujek and Ziemowit coal mines that occurred between 1993 and 1995, and seismic events
from the Polkowice copper mine that occurred between 1994 and 1996 and from the Rudna copper mine that occurred between 1994
and 2004 were considered. Their source parameters and focal mechanisms were known in most cases from previous studies. Altogether
108 seismic pairs from coal mines and 118 pairs from copper mines were found, forming doublets, triplets and quadruplets,
within the magnitude range from 0.7 to 3.5. The distance and time intervals between two events forming pairs are not dependent
on magnitude of these events.
The focal mechanism of seismic events forming pairs is similar in over 60 percent of pairs at coal mines and in about one
third of pairs at copper mines. Spatial distributions of doublets in particular sections of coal and copper mines display
dominant linear trends, characteristic for a given area, which are often in conformity with the direction of nodal planes
determined by fault plane solution of one or both the events forming a doublet. In such cases, the rupture plane can be discriminated
among the nodal planes. 相似文献
90.
Jerzy Jankowski Václav Petr Jana Pečová Oldřich Praus Reviewer A. Janáčková 《Studia Geophysica et Geodaetica》1979,23(1):89-93
u¶rt;um ¶rt;a ma ua m u¶rt;uu n mam amu n aum auau ¶rt;a a n -a am anam. 相似文献