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371.
天山乌鲁木齐河源1号冰川物质平衡对气候变化的敏感性研究   总被引:42,自引:23,他引:19  
刘时银 《冰川冻土》1998,20(1):9-13
应用度日物质平衡模式对天山乌鲁木齐河源1号冰川物质平衡及平衡线高度对气候变化的敏感性进行了研究.结果表明,位于大陆性气候区且具有暖季补给特征的乌鲁木齐河源1号冰川物质平衡对气候变化的敏感性要小于海洋性冰川,升温1℃或增加20%的降水可引起平衡线上升81m或下降31m.此外,气温与降水在物质平衡形成过程中的作用是不同的,气温引起物质平衡剖面以旋转方式变化,而降水可导致其平移方式的响应.若未来升温2℃时,即使降水增加30%,1号冰川向负平衡变化仍然不能得到遏制.  相似文献   
372.
三峡工程岩体破坏分析中面连通率研究   总被引:4,自引:0,他引:4  
介绍了面连通率在岩体破坏研究中的表述方法。连通率的大小可反映破坏概率的大小。选择可能滑动面进行连通率计算方法有:多个结构面组成的折面;单个结构面的扩展面。两种面连通率均反映了在空间平面上结构面的发育程度,揭露更多隐藏的破坏性信息,有利于定量、定位分析岩体稳定性。  相似文献   
373.
在瓦斯突出煤体和非突出煤体的电学性质研究基础上 ,研究了瓦斯突出煤层的无线电波响应特征 ,为利用无线电波透视技术探测瓦斯突出煤体和进行瓦斯突出带的非接触式预测提供了理论基础  相似文献   
374.
Interplanetary transients with particular signatures different from the normal solar wind have been observed behind interplanetary shocks and also without shocks. In this paper we have selected four well-known transient interplanetary signatures, namely: magnetic clouds, helium enhancements and bidirectional electron and ion fluxes, found in the solar wind behind shocks, and undertaken a correlative study between them and the corresponding solar observations. We found that although commonly different signatures appear in a single interplanetary transient event, they are not necessarily simultaneous, that is, they may belong to different plasma regions within the ejecta, which suggests that they may be generated by complex processes involving the ejection of plasma from different solar regions. We also found that more than 90% of these signatures correspond to cases when an H flare and the eruption of a filament occurred near solar central meridian between 1 and 4 days before the observation of the disturbance at 1 AU, the highest association being with flares taking place between 2 and 3 days before. The majority of the H flares were also accompanied by soft X-ray events. We also studied the longitudinal distribution of the associated solar events and found that between 80% and 90% of the interplanetary ejecta were associated with solar events within a longitudinal band of ±30° from the solar central meridian. An east-west asymmetry in the associated solar events seems to exist for some of the signatures. We also look for coronal holes adjacent to the site of the explosive event and find that they were present almost in every case.  相似文献   
375.
The equations for a compositional model for simulation of a two-phase, three-component system with inter-phase mass transfer are developed. Emphasis is placed on development of inter-phase mass transfer equations for incorporation of rate-limited inter-phase mass transfer. Due to the nature of the three-component systems considered, a single-film model may be inadequate and a two-film model must be utilized. A two-film model accounts for the simultaneous transfer of components in both directions across phase interfaces. The effect of interaction between components on diffusion is considered using a general form of Fick's Law. A Hand Plot representation of ternary phase behavior is chosen since it allows for straightforward calculation of miscibility of bulk phases under conditions of local non-equilibrium. The developed set of equations form the basis for a numerical model to simulate the enhanced removal of non-aqueous phase liquids (NAPLs) from porous media using single-component alcohol floods.  相似文献   
376.
Six peat samples obtained from the Holocene and the Weichselian of the Philippi peat deposit, eastern Macedonia, Greece, were analyzed for 48 trace elements by Inductively Coupled Plasma–Mass Spectrometry (ICP–MS). The ash contents of these samples were also determined. Most of the trace elements are associated with the minerals in the peat, while Ge, Mo, Pb, Se, Ta, Tl, U, and W display a greater affinity with the organic matter. Compared with crustal averages (Clarke concentrations), the Philippi peat is enriched in some elements (Ag, As, Au, Cd, Mo, Se, Te, U, and W) because of the respective mineralizations in the area. The Philippi peat is also enriched in Cr, Cu, Mo, Pb, Sc, Sn, T, V, Y, and Zn in comparison with typical fen peats, as well as in As, Cr, Mo, Se, and U in comparison with typical coals. Climatic and hydrogeological conditions strongly influenced the peat-forming environment resulting in a differentiation between Holocene and Weichselian peat. Generally, the Holocene peat contains lower concentrations of trace elements in the northern and southern part of the fen, than the Weichselian one. The opposite trend is observed in the fen area close to the western basin margins.  相似文献   
377.
攀枝花钒钛磁铁矿床是我国特大型晚期岩浆分凝型矿床。本文首次用TFe/TiO2比值对矿带、矿层、火成堆积旋回进行了详细划分,同时对断层位置、性质及矿床成因进行了判定,并提出在层状辉长岩体中,当TFe/TiO2比值小于2∶1的部位是寻找独立钛铁矿矿床最佳地段  相似文献   
378.
We present the luminosity function and measurements of the scalelengths, colours and radial distribution of dwarf galaxies in the Coma cluster down to R =24. Our survey area is 674 arcmin2; this is the deepest and most detailed survey covering such a large area.
Our measurements agree with those of most previous authors at bright and intermediate magnitudes. The new results are as follows.
(1) Galaxies in the Coma cluster have a luminosity function φ( L )∝ L α that is steep (α∼−1.7) for −15< MR <−11, and is shallower brighter than this. The curvature in the luminosity function at MR ∼−15 is statistically significant.
(2) The galaxies that contribute most strongly to the luminosity function at −14< MR <−12 have colours and scalelengths that are consistent with those of local dwarf spheroidal galaxies placed at the distance of Coma.
(3) These galaxies with −14< MR <−12 have a colour distribution that is very strongly peaked at B − R =1.3. This is suggestive of a substantial degree of homogeneity in their star formation histories and metallicities.
(4) These galaxies with −14< MR <−12 also appear to be more confined to the cluster core ( r ∼200 kpc) than the brighter galaxies. Alternatively, this observation may be explained in part or whole by the presence of an anomalously high number of background galaxies behind the cluster core. Velocity measurements of these galaxies would distinguish between these two possibilities.  相似文献   
379.
We present the results from a CCD survey of the B -band luminosity function of nine clusters of galaxies, and compare them to published photographic luminosity functions of nearby poor clusters like Virgo and Fornax, and also to the field luminosity function. We derive a composite luminosity function by taking the weighted mean of all the individual cluster luminosity functions; this composite luminosity function is steep at bright and faint magnitudes and is shallow in-between.
All clusters have luminosity functions consistent with this single composite function. This is true both for rich clusters like Coma and for poor clusters like Virgo.
This same composite function is also individually consistent with the deep field luminosity functions found by Cowie et al. and Ellis et al., and also with the faint end of the Las Campanas Redshift Survey R -band luminosity function, shifted by 1.5 mag. A comparison with the Loveday et al. field luminosity function, which is well determined at the bright end, shows that the composite function, which fits the field data well fainter than M B=−19, drops too steeply between M B=−19 and −22 to fit the field data there.  相似文献   
380.
The recently finished Edinburgh UVX quasar survey at B <18 is used together with other complete samples to estimate the shape and evolution of the optical luminosity function in the redshift range 0.3< z <2.2. There is a significantly higher space density of quasars at high luminosity and low redshift than previously found in the PG sample of Schmidt & Green, with the result that the shape of the luminosity function at low redshifts ( z <1) is seen to be consistent with a single power law. At higher redshifts the slope of the power law at high luminosities appears to steepen significantly. There does not appear to be any consistent break feature which could be used as a tracer of luminosity evolution in the population.  相似文献   
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