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101.
In this paper an analytical method has been proposed to predict the net ultimate uplift capacity of the single bent pile and
pile group with a bent embedded in sand considering arching effects. Arching develops due to relative compressibility of sand
relative to pile which activates the soil-pile friction. The method takes into consideration the embedded length (L), diameter of the pile (d), bent angle, surface characteristics of pile, group configuration, spacing of the pile group and the soil properties. Log
spiral failure surface with parabolic arch shape was assumed in the analysis. Theoretical investigation for uplift capacity
was been carried out for the single bent pile and group of pile (2 × 1, 2 × 2) embedded in sand. The variable used in the
analysis were embedded length to pile diameter (L/d = 15, 20 and 25), spacing in the group (3d, 4d and 6d) and angle of bent (6°, 14° and 20°). Typical charts for evaluation of net ultimate uplift capacity for pile groups are presented
through the figures. Comparison of theoretical results shows good agreement with established experimental results. 相似文献
102.
When neglecting capillarity, two-phase incompressible flow in porous media is modelled as a scalar nonlinear hyperbolic conservation
law. A change in the rock type results in a change of the flux function. Discretising in one dimension with a finite volume
method, we investigate two numerical fluxes, an extension of the Godunov flux and the upstream mobility flux, the latter being
widely used in hydrogeology and petroleum engineering. Then, in the case of a changing rock type, one can give examples when
the upstream mobility flux does not give the right answer. 相似文献
103.
Summary The Palim granite, hosted by the metasedimentary country rocks in the Bastar tin province, is a heterogeneous pluton that
comprises hornblende granite, biotite granite and two-mica granite. Spherical inhomogeneous surmicaceous enclaves occur within
the granites with coarse grained cores of muscovite mantled by finer muscovite-quartz-biotite (± sillimanite) rims. Geochemical
features imply that the granites are highly evolved and geochemically distinct. Petrographic and geochemical considerations
point towards a transition from metaluminous I-type hornblende-bearing granite in the south to peraluminous volatile-enriched
S-type like lithologies (biotite and two-mica granites) towards north. Modeling of highly incompatible elements such as Nb
and Cs, implies 31 to 33% assimilated fractional crystallization of a melt with an initial composition close to that of the
hornblende granite to form the two-mica granite. Hornblende geobarometry, plagioclase-hornblende thermometry (in hornblende
granite) and phengite barometry (in two-mica granite), yield P-T estimates of 5–7 kb/725°–760 °C, and 6 kb/700 °C, respectively.
The study further implies that a genetic link exists between granite magmatism and the formation of tin pegmatites in the
region. The preponderance of peripheral pegmatites to the north-east of the Palim granite is regarded a result of outward
crystal-melt fractionation and tectonic tilting of the pluton.
Received October 21, 1999; revised version accepted December 12, 2000 相似文献
104.
S. N. Rajaguru Avijit Gupta V. S. Kale Sheila Mishra R. K. Ganjoo L. L. Ely Yahouda Enzel V. R. Baker 《地球表面变化过程与地形》1995,20(5):407-421
The 1300 km long Narmada River flows along a structural lineament, alternating between constricting rocky gorges and rapids, and meandering wide alluvial reaches. Channel forms and processes were studied in a 120 km long section of an alluvial reach. Channel size, shape and bedforms in the Narmada River are related to very large floods which have occurred three times in this century. During such floods the entire 400 m wide channel is utilized and 10–15 m high cliffs on both sides operate as riverbanks. Normally, even the high flows of the south-western monsoon are insufficient to fill the whole channel, and hence their effects are limited to building of discontinuous floodplains between the cliffs and modifying bedforms and bars. A channel-in-channel topography is thus created. The very large floods are also responsible for erosion of the rocky stretches and building of point bars. The river meanders, but its movement is restricted because of (1) rocky gorges and scablands operating as anchor points at intervals, and (2) the presence of high alluvial cliffs which are topped on extremely rare occasions. In spite of being located in a tectonically active zone in a monsoon setting, it is the exceptional high-magnitude floods at irregular intervals which control the form and behaviour of the Narmada River. 相似文献
105.
106.
107.
S.K. Mishra 《International Journal of Mineral Processing》1982,9(1):59-73
Calcite is generally associated with apatite minerals in phosphate deposits. To explore the possibility of separating these minerals by a soap flotation technique, their electrokinetic properties and flotation behaviour were studied in the presence of sodium oleate.Microelectrophoresis data indicate oleate adsorption on these minerals, and from Hallimond-tube flotation tests it has been noted that in a controlled pH environment and for a certain sodium oleate concentration range, separation of these minerals is possible.The study of apatite/calcite-sodium metasilicate-sodium oleate systems indicates the preferential adsorption of silicate at the calcite surface. This suggests the potential use of sodium metasilicate as the modifying agent for the separation of apatite from calcite by depressing calcite when using sodium oleate as collector. 相似文献
108.
Summary This paper discusses the disturbance produced in an infinite layer of non-homogeneous elastic material characterised by =0 n and =0n(n>0) where and are the density and shear modulus respectively of the material, due to periodic torsional force applied on the wall of a cylindrical hole in the layer. The variation of the displacement component with the radius vector is shown graphically and compared with the corresponding homogeneous case. 相似文献
109.
110.