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471.
472.
针对埕岛油田复杂的自然地理和气候条件,生产中配套应用了适合浅海油田开发的油藏工程、钻采工艺、海工工程、油水井监测、自动化控制及油藏生产管理综合调整等技术,使一个浅海边际油田开发获得了较高的效益,并形成了独具特色的海上油田高速高效开发配套技术。 相似文献
473.
The response of laterally loaded pile foundations may be significantly important in the design of structures for such loads. A static horizontal pile load test is able to provide a load–deflection curve for a single free‐head pile, which significantly differs from that of a free‐ or fixed‐head pile group, depending on the particular group configuration. The aim of this paper is to evaluate the influence of the interaction between the piles of a group fixed in a rigid pile cap on both the lateral load capacity and the stiffness of the group. For this purpose, a parametric three‐dimensional non‐linear numerical analysis was carried out for different arrangements of pile groups. The response of the pile groups is compared to that of the single pile. The influence of the number of piles, the spacing and the deflection level to the group response is discussed. Furthermore, the contribution of the piles constituting the group to the total group resistance is examined. Finally, a relationship is proposed allowing a reasonable prediction of the response of fixed‐head pile groups at least for similar soil profile conditions. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
474.
The methods used in conducting static stability analyses have remained pertinent to this day for reasons of both simplicity and speed of execution. The most well‐known of these methods for purposes of stability analysis of fractured rock masses is the key‐block method (KBM). This paper proposes an extension to the KBM, called the ‘key‐group method’ (KGM), which combines not only individual key‐blocks but also groups of collapsable blocks into an iterative and progressive analysis of the stability of discontinuous rock slopes. To take intra‐group forces into account, the Sarma method has been implemented within the KGM in order to generate a Sarma‐based KGM, abbreviated ‘SKGM’. We will discuss herein the hypothesis behind this new method, details regarding its implementation, and validation through comparison with results obtained from the distinct element method. Furthermore, as an alternative to deterministic methods, reliability analyses or probabilistic analyses have been proposed to take account of the uncertainty in analytical parameters and models. The FOSM and ASM probabilistic methods could be implemented within the KGM and SKGM framework in order to take account of the uncertainty due to physical and mechanical data (density, cohesion and angle of friction). We will then show how such reliability analyses can be introduced into SKGM to give rise to the probabilistic SKGM (PSKGM) and how it can be used for rock slope reliability analyses. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
475.
476.
The propagation of elastic waves along a cylindrical borehole filled with/without liquid and embedded in an infinite porous
medium saturated by two immiscible fluids has been studied. The theory of porous media saturated by two immiscible fluids
developed by Tuncay and Corapcioglu (1997) is employed. Frequency equations determining the phase velocity of axial symmetric
waves are obtained. It is found that the surface waves along cylindrical borehole are dispersive. The dispersion equation
of Rayleigh-type surface waves along the boundary of a poroelastic solid half-space saturated by two immiscible fluids is
also obtained. Some special cases have been deduced and the dispersion curves are obtained numerically for a peculiar model.
It is found that the density of fluids affects the Rayleigh mode. 相似文献
477.
Lead isotopic compositions of mineral separates are presented from the mineralized zones (Roby, Twilight, and High Grade zones)
of the Lac des Iles palladium deposit (approximately 2.69 Ga) and tonalitic country rocks (approximately 2.727 to 2.775 Ga)
in the Wabigoon subprovince of the western Superior Province of Canada. Plagioclase separates show Pb isotope ratios similar
to those of the late Archean depleted mantle. Sulfide minerals coexisting with plagioclase have a more radiogenic Pb isotope
composition, but very low concentrations of U (<0.2 ppb U) and Th (<0.01 ppb) compared to Pb (≫50 ppb). The isotope data are
consistent with a model involving the incorporation of radiogenic Pb from country rocks to sulfide melt near the base of the
magma chamber or along the conduit of the parental magmas. The proposed interpretation is also supported by decreasing Cu/Pd
ratios from earlier barren to late fertile gabbro intrusions in the complex. The ponding sulfide melt became enriched in platinum
group elements, as it was interacting with a large magma volume during the evolution of the Lac des Iles igneous complex. 相似文献
478.
分析了几类特殊有限群的自同构群的次单性,得到了以下结论:(1)若n〉3且n≠6,Aut(An)均含有一个子群是次单群;(2)按照循环群Zn的阶的几种不同情况讨论了Aut(Zn)在哪些情况下包含一个子群是次单群,并给出了判定阶为P^i,2p^i(p为素数)的循环群的自同构群是否含有子群是次单群的计算机实现。 相似文献
479.
M. D. Roberts D. L. Reid J. A. Miller I. J. Basson M. Roberts D. Smith 《Mineralium Deposita》2007,42(3):271-292
The Merensky Reef of the Bushveld Complex occurs in its highest stratigraphic position as a heterogeneous, pegmatitic, feldspathic
melanorite bounded by two narrow chromitite stringers at the base of the Merensky Cyclic Unit (MCU). In the Swartklip Facies
of the Rustenburg Layered Suite, the occurrence of widespread thermal and mechanical erosion termed “potholing” has led to
the subdivision of the Merensky Reef into Normal Reef and Regional Pothole Reef sub-facies. The transition between the two
sub-facies occurs where the MCU transgresses the lower chromitite stringer of the Normal Merensky Reef and cuts down into
the underlying cumulate lithologies. In the Regional Pothole Reef at the Northam Platinum Mine, several economic reef types
are identified, where the Merensky Reef becomes conformable to cumulate layering, in particular, to the footwall marker (NP2
reef type) and the upper pseudoReef (P2 reef type). The Normal Merensky Reef, as well as the P2 and NP2 Reefs, contains economic
platinum group element (PGE) grades and includes the lower portion of the MCU melanorite and the Merensky Chromitite. Whole
rock geochemistry indicates that this package is compositionally identical in Normal, P2, and NP2 Reefs, suggesting that the
base of the MCU is a relatively homogeneous drape over both Normal and Regional Pothole Reef regions. However, the lower sections
of the three Reefs are variables depending on the depth of transgression of the MCU. In the Normal and P2 reef types, transgression
by the MCU was arrested within harzburgites, melanorites, and norites, resulting in coarse, pegmatitic textures in the immediate
footwall units. For the NP2 Reef, transgression by the MCU was arrested within leucocratic rocks and resulted in the formation
of troctolites below the Merensky Chromitite. These troctolites are characterised by a coupled relationship between olivine
and sulphides and by changes in major element chemistry and PGE contents relative to equivalent units in the footwall of the
Normal Reef. Along with micro-textural relationships, these features suggest that troctolization of leucocratic cumulates
in the NP2 Reef beneath the Merensky chromitite was a result of a reactive infiltration of a chromite-saturated melt and an
immiscible sulphide liquid from the overlying MCU, rather than a significant fluid flux from below. In all reef types, the
concentration of S defines symmetrical peaks centred on the Merensky Chromitite (and chromitites from pre-existing cyclic
units in Normal and P2 Reefs), whereas PGE concentrations define asymmetrical peaks with higher PGE contents in reconstituted
footwall rocks relative to the MCU melanorite. This signature is attributable to a magmatic model of PGE collection followed
by deposition towards the base of the MCU and within reconstituted footwall rocks. The continuity of the asymmetrical magmatic
PGE signature between the Normal Reef and Regional Pothole Reef sub-facies indicates that PGE mineralization inherent to the
Merensky magma occurred as a drape over a variably eroded and subsequent texturally and geochemically reworked or reconstituted
footwall. 相似文献
480.
Toshifumi Komatsu Chen Jinhua Hiroaki Ugai Koji Hirose 《Journal of Asian Earth Sciences》2007,29(5-6):795-802
Trigonioides goshourensis n. sp. and Trigonioides amakusensis Kikuchi and Tashiro occur in the late Albian Eboshi Formation of the Goshoura Group in Kyushu, Japan. These Albian species are characterized by three radial pseudocardinal teeth on the thick and wide hinge plate, and are probably ancestors of Cenomanian species of Trigonioides (Kumamotoa) with four radial pseudocardinal teeth. This chronological relation may be important for the correlation of non-marine Cretaceous strata in East Asia. In addition, the habitat of T. amakusensis is interpreted as estuarine tidal flats under brackish water conditions, although Trigonioides is generally a freshwater bivalve genus. 相似文献