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881.
Gypsum crystals of authigenic origin have been found in manganese nodules of the deep-sea sediment surface (4500-5500 m water depth) from the Central Pacific Ocean. 相似文献
882.
Prof. Dr. A. Pabst 《Mineralogy and Petrology》1978,25(4):245-256
Zusammenfassung Taramellit kommt im westlichen Nordamerika an mindestens acht Fundstellen vor, wo er bis jetzt wenig beachtet wurde. Die Taramellite dieser Fundstellen sind alle sehr Ti-reich. Bisher wurde Taramellit nach dem ersten Vorkommen, Candoglia in Italien, meist als faserig beschrieben. Die Ti-reichen Taramellite in Nordamerika, besonders die in California, welche mit Sanbornit und Gillespit vorkommen, erscheinen aber als gut ausgebildete Einkristalle. Es wurden viele solche Kristalle goniometrisch gemessen. Obgleich etwa dreißig Formen verzeichnet wurden, ist der Habitus der orthorhombischen Kristalle meist durch das Vorherrschen der Pinakoide und einiger {hk0} und {0kl} Prismen bedingt. Am häufigsten ist der tafelige habitus nach {100}.
Mit 3 Abbildungen
herrn Prof. Dr.H. Meizner zum 70. Geburtstag gewidmet. 相似文献
On the morphology of taramellite
Summary Taramellite is known from at least eight localities in western North America but has received little notice. The taramellite at all of these localities is especially Ti-rich. Hitherto taramellite has mostly been described as fibrous after its habit at the type locality, Candoglia, Italy. The Ti-rich taramellites of North America, especially those found with sanbornite and gillespite in California, occur as well-developed single crystals. Many such crystals were measured goniometrically. Though about thirty forms were recorded, the habit of the orthorhombic crystals is mostly determined by the pinacoids and a few {hk0} and {0kl} prisms. A tabular habit with {100} dominant is most common.
Mit 3 Abbildungen
herrn Prof. Dr.H. Meizner zum 70. Geburtstag gewidmet. 相似文献
883.
An examination of day-to-day and monthly mean positions of the electrojet axis in relation to the changes in the apparent solar declination, in the Indian equatorial region shows marked association between the two. For relatively quiet days, significant correlations are observed between the solar declination and each of the parameters, the northernSq focal latitude, the jet axis and the line of maximumSq(H). From the significant mutual association of these parameters, it has been suggested that the equatorial electrojet could be a part of the world-wideSq current system. 相似文献
884.
Dr. A. Blasi 《Mineralogy and Petrology》1979,26(3):139-148
Summary Direct and reciprocal lattice constant variance-covariance matrices when involved in the Law of Propagation of Errors can be used to gain a full evaluation of the error terms in mineralogical quantities expressed in terms of lattice constants. Properties and relationships which mutually connect the two matrices are discussed, with emphasis placed on physical dimensions. A practical application is given by calculating the error terms in the structural indicators (bc) and (**) of alkali feldspars. The differences between values obtained by using both variances plus covariances and those obtained using variances alone, are very small. However, as the calculations are completely automated, the full formulation using variances plus covariances represents a suitable better approach.
With 1 Figure 相似文献
Mineralogische Anwendungen der Varianz-Kovarianz-Matrizen der Gitterkonstanten
Zusammenfassung Varianz-Kovarianz-Matrizen der direkten und reziproken Gitterkonstanten können beim Fehlerfortpflanzungsgesetz benützt werden, um eine vollständige Auswertung der Fehlerausdrücke mineralogischer Größen, ausgedrückt durch Gitterkonstanten, zu erhalten. Eigenschaften und Beziehungen, welche diese beiden Matrizen gegenseitig verknüpfen, werden mit Betonung physikalischer Dimensionen diskutiert. Eine praktische Anwendung wird gegeben, indem die Fehlerausdrücke der strukturellen Indikatoren (bc) und (**) von alkalifeldspäten berechnet werden. Die Differenzen zwischen den Werten, die bei Benützung von Varianzen und Kovarianzen, bzw. nur von Varianzen erhalten wurden, sind sehr klein. Da aber die Berechnungen voll automatisiert sind, bietet die vollständige Formulierung mit Varianzen plus Kovarianzen eine brauchbare bessere Methode.
With 1 Figure 相似文献
885.
M. T. Krupenin A. V. Maslov I. D. Tsybulenko R. A. Nafikov V. G. Petrishcheva 《Lithology and Mineral Resources》2000,35(3):267-277
A property of swelling on heating to yield firm lightweight granules has first been revealed for lowcarbonaceous shales (LCS)
from the Riphean stratotype in the Bashkirian Megaanticlinorium, Southern Urals. These granules possess all technological
properties of “keramzite” or claydite (an artificial, expanded clayey material) and can successfully substitute this material.
Moreover, the procedure of their manufacture, analogous to the manufacture of “shungizite” (an artificial carbonaceous-clayey
material) from Lower Proterozoic clayey rocks of Karelia, is more economical than that for keramzit. Productive beds of the
homogeneous LCS make up extended bodies tens of meters thick. At the present time, they can be used as cover rocks during
the exploitation of the Bakal siderite deposits. The LCS represent fine-grained quartz-chlorite-sericite aggregates (with
variable relationships between the major components), bearing fine-dispersed shungite in amounts of 0.5–1.0%. High-quality
raw material of this kind is characterized by a fine-dispersed admixture of a mixed-layer clayey material bearing montmorillonite
and vermiculite. Geological, lithological, mineralogical, and chemical prognostic criteria have been developed for the shungizite
raw material. It has been concluded that this construction material, new for the Urals, is promising for industrial use 相似文献
886.
887.
888.
Zusammenfassung Die massenspektrometrische Analyse kleinster Gasmengen von H2, O2, CO, CO2, CH4 und H2O ist infolge der Beeinflussung durch das Meßsystem mit beachtlichen Schwierigkeiten verbunden. Die Beeinflussung erfolgt einerseits durch Reaktionen der Gase mit heißen Metalloberflächen und andererseits durch im System vorhandene Glasoberflächen. Bei einer entprechenden apparativen Anordnung, Erhitzen der Proben und Trennung der Gase durch Kühlfallen, können Gasmengen in und auf Mineralen bis zu 0,005 mm3/NDT quantitativ bestimmt werden. Die Apparatur ist durch thermische Zersetzung von Muskovit-, Calcitkristallen usw. geeicht. Die Anwendung dieser Methode auf das Gebiet der Chemie und Mineralogie sowie die Grenzen und Möglichkeiten einer quantitativen Analyse von Restgasen wird gezeigt.
Mit 5 Abbildungen 相似文献
Mass-spectrometric analysis of gases of the system C-H-O in minerals
Summary The analysis by mass-spectrometer of smallest amounts of gases H2, O2, CO, CO2, CH4 and H2O, respectively, meets with considerable difficulties, because of the influence by the measuring system. The influence is caused by interactions of the gases with hot metal surfaces on one hand, and glass surfaces on the other hand. By a suitable arrangement of apparatus and procedures, such as heating the samples and separating the gases by cooling traps, the gas amounts in and on minerals can be quantitatively determined up to 0.005 mm3/SPT. The apparatus is calibrated by thermal dissociation of crystals like muscovite, calcite etc. The application of this method in chemistry and mineralogy is treated as well as the limits and the possibility of the quantitative analysis of residual gas.
Mit 5 Abbildungen 相似文献
889.
The Hodson mining district is in the westernmost foothills of the Sierra Nevada in California, about 17 km west of the town of Angels Camp. This district is part of the West Gold Belt, which lies about 12–16 km west of, and generally parallel to, the better known Mother Lode Gold Belt in central California. The district produced several million dollars worth of Au between about 1890 and 1940. 相似文献
890.
Fe-rich tholeiitic liquids and their cumulate products in the Pleasant Bay layered intrusion, coastal Maine 总被引:4,自引:0,他引:4
R. A. Wiebe 《Contributions to Mineralogy and Petrology》1997,129(4):255-267
Fe-rich tholeiitic liquids are preserved as chilled pillows and as the chilled base of a 27 meter thick macrorhythmic layer
in the Pleasant Bay mafic-silicic layered intrusion. The compositions of olivine (Fo1) and plagioclase (An13−8) in these extremely fine grained rocks suggest that they represent nearly end stage liquids that formed by fractionation
of tholeiitic basalt. Their major element compositions (∼17.5 wt% FeOT and 54 wt%SiO2) closely resemble highly evolved glasses in the Loch Ba ring dike and some recent estimates of end-stage liquids related
to the Skaergaard layered intrusion, and are consistent with recent experimental studies of tholeiite fractionation. Their
trace element compositions are consistent with extensive earlier fractionation of plagioclase, olivine, clinopyroxene, ilmenite,
magnetite and apatite. The mineral assemblage of the chilled rocks (olivine, clinopyroxene, quartz, ilmenite and magnetite),
apatite saturation temperatures, and very low Fe3+/Fe2+indicate conditions of crystallization at temperatures of about 950 °C and f
O
2
about two log units below FMQ. Cumulates that lie about 3 meters above the chilled base of the macrorhythmic layer contain
cumulus plagioclase, olivine, clinopyroxene, ilmenite, apatite and zircon. This mineral assemblage and the Fe-Mg ratio in
clinopyroxene cores suggest that this cumulate was in equilibrium with a liquid having a composition identical to that of
the chilled margin which lies directly beneath it. The high FeOT and low SiO2 concentrations of this cumulate (23.3 and 45.8 wt%, respectively) are comparable to those in late stage cumulates of the
Skaergaard and Kiglapait intrusions. This association of a chilled liquid and cumulate in the Pleasant Bay intrusion suggests
that late stage liquids in tholeiitic layered intrusions may have been more SiO2-rich than field-based models suggest and lends support to recent experimental studies of tholeiite fractionation at low f
O2 which indicate that saturation of an Fe-Ti oxide phase should cause FeOT to decrease in the remaining liquid.
Received: 17 January 1997 / Accepted: 10 June 1997 相似文献