全文获取类型
收费全文 | 1279篇 |
免费 | 30篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 52篇 |
大气科学 | 61篇 |
地球物理 | 613篇 |
地质学 | 298篇 |
海洋学 | 22篇 |
天文学 | 235篇 |
综合类 | 5篇 |
自然地理 | 25篇 |
出版年
2018年 | 31篇 |
2017年 | 32篇 |
2016年 | 54篇 |
2015年 | 33篇 |
2014年 | 47篇 |
2013年 | 55篇 |
2012年 | 20篇 |
2011年 | 31篇 |
2010年 | 43篇 |
2009年 | 37篇 |
2008年 | 32篇 |
2007年 | 28篇 |
2006年 | 28篇 |
2005年 | 13篇 |
2004年 | 23篇 |
2003年 | 21篇 |
2002年 | 29篇 |
2001年 | 26篇 |
2000年 | 22篇 |
1999年 | 14篇 |
1998年 | 19篇 |
1997年 | 16篇 |
1996年 | 31篇 |
1995年 | 23篇 |
1994年 | 23篇 |
1993年 | 33篇 |
1992年 | 21篇 |
1991年 | 16篇 |
1990年 | 16篇 |
1989年 | 25篇 |
1988年 | 18篇 |
1987年 | 22篇 |
1986年 | 21篇 |
1985年 | 19篇 |
1984年 | 18篇 |
1983年 | 24篇 |
1982年 | 21篇 |
1981年 | 15篇 |
1980年 | 20篇 |
1979年 | 20篇 |
1978年 | 26篇 |
1977年 | 24篇 |
1976年 | 18篇 |
1975年 | 17篇 |
1974年 | 13篇 |
1973年 | 18篇 |
1972年 | 12篇 |
1971年 | 21篇 |
1970年 | 11篇 |
1969年 | 13篇 |
排序方式: 共有1311条查询结果,搜索用时 161 毫秒
921.
Jan Kozák Jan Šílený Aleš Špičák Reviewer V. Červený 《Studia Geophysica et Geodaetica》1984,28(2):156-163
¶rt;u u uu uuu ¶rt; n¶rt; ¶rt;au m ¶rt;u uu m n¶rt;uu u numuu m¶rt;. mam n¶rt; aamumuu anamu u ; n¶rt; mu aaa amu ¶rt;u n¶rt;uu nmu aua ¶rt;u u uu a mu m muna. 相似文献
922.
Summary A computational method for fitting smoothed natural or periodic bicubic splines to data given at the grid points of a rectangular network is proposed. The one-dimensional smoothed spline fit, introduced by Reinsch, defines the smoothness properties well. These are generalized for a two-dimensional approximation by solving the corresponding variational problem. The defining equations are presented here together with an efficient method of determining the necessary parameters and computing the resultant spline.
¶rt;u u m¶rt; annuauu ¶rt; uu auauu nau m m¶rt; a [12]. am am nua m¶rt; au m¶rt; a ¶rt; u ¶rt; n. nua aum n¶rt;aa ¶rt; annuauu ¶rt; uu, a¶rt;a uu auu a nu n mu, mmu uuuu naau uu ( m auam) uuuu naau, nu¶rt;uuu ¶rt; anauu. mam um uma uum, n m aum annuu u . namuu uu a omaa naa a FORTRAN.相似文献
923.
Karel Pěč Zdeněk Martinec Jana Pěčová Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1985,29(2):139-162
Summary Matrix formulae for the intensities of the M- and E-fields have been derived. They have been applied to express the apparent resistivity, the transfer function, as well as the frequency equation determining the frequencies of free motion of the M- and E-waves. A fast algorithm for computing the transfer function and the apparent resistivity has been suggested.
¶rt; u ¶rt; nu n u u u una. n u n¶rt;: nuu, u u u u, n¶rt; u u . ¶rt; au ¶rt; u u u u nuu.相似文献
924.
Pavla Kočíková Věnceslava Pretlová Reviewer O. Zikmunda 《Studia Geophysica et Geodaetica》1985,29(1):75-99
Summary The inclusion of cloudiness characteristics, obtained by computer analysis of multispectral satellite photographs, in the objective analysis of the dew-point temperature deficit is suggested for the mesomodel. The basic principle of the method is the correction of mathematically packed data using processed satellite cloudiness observations. Special fast algorithms for constructing bicubic splines are used to effect the basic mathematical packing.
¶rt;aam m¶rt; ¶rt; u aamumu a na ma n aaua nma nmu u nu nu uum au mu aau ¶rt;uuma mnam mu ¶rt; ¶rt;u. m¶rt;a m u amamuu nm ¶rt;a nu nu nmu u. aau ¶rt;a unm nua m aum ¶rt; muu uuu na.相似文献
925.
Summary The temperature-depth distribution along the 250 km long Czechoslovak part of DSS profile VII was calculated to a depth of 40 km. The two-dimensional solution of the steadystate equation of heat conduction in an inhomogeneous medium, obtained by means of the finite difference method, was used. By resolving the observed surface heat flow into two components, one of which is generated by heat sources inside the model and the other is connected with the heat flow from deeper parts of the Earth, the heat flow at the lower boundary of the model was estimated and used here as a boundary condition in the numerical solution. To reduce the differences between the calculated and observed surface heat flow, the heat sources in the upper 10 km of model were optimized. A regularization process, in which the variation of the sought function was limited, was used both to estimate the heat flow and to optimize the sources.
u n¶rt;u n ¶rt; (¶rt;u 250 ) nu . . VII ¶rt;u 40 . un ¶rt; u u nn¶rt;u ¶rt; u ¶rt;¶rt; ¶rt; ¶rt; . n u u n n n ¶rt; u, ¶rt; u u uuu n u ¶rt;u, a u n, n uu ¶rt;u u un ¶rt; u u nu u uu u. u na¶rt;u ¶rt; u u u nu nu ¶rt; nuuu uu n u 10 ¶rt;u. nu , u nu nuuuu uu n un n uuu, uuu uau u uu .相似文献
926.
Jürgen Bremer Jan Laštovička Reviewer L. Křivský 《Studia Geophysica et Geodaetica》1989,33(2):198-205
Summary The influence of the IMF sector structure on the total ozone content is studied in the European middle latitudes (5 stations,46°–52°N, 1°W–20°E) for the winters of the period 1963–1982. The average effect of the IMF sector boundary crossing (SBC) is very weak. The correction for the seasonal trend is quite crucial. Only detrended results are considered to be reliable. A statistically significant and relatively large effect is found to exist in the total ozone only for geoactive proton sector boundaries, while there is no demonstrable effect for non-proton (common) sector boundaries. The effect of proton boundaries consists in a decrease of the total ozone from higher values before the IMF SBC to lower values after the IMF SBC and it differs from the common types of IMF SBC effects. Our results seem to explain the contradiction between results obtained by other authors.
Presented at the XIX General Assembly of IUGG, Vancouver 1987. 相似文献
¶rt;m uu m mm nam aum n () a n ¶rt;au a nu ¶rt;u uma (5 mau, 46° – 52° .., 1° .¶rt;. – 20° .¶rt;.) ¶rt; u nu¶rt;a 1963–1982. ¶rt;u m nu mau () a. naa a m¶rt; ma. mam mau m¶rt;a umam ¶rt;mu. mamumuu au u a m a¶rt; n ¶rt;auu a m ¶rt;amu nm mau. a mau ua ma m. m nm mau mum na¶rt;uu n ¶rt;au a u au ¶rt; ¶rt; uu au n . a am, m au mam m nmuu ¶rt; mamau ¶rt;u am.
Presented at the XIX General Assembly of IUGG, Vancouver 1987. 相似文献
927.
František Jiříček Pavel Tříska E. E. Titova T. A. Yakhnina O. A. Maltseva Reviewer S. Fischer 《Studia Geophysica et Geodaetica》1986,30(4):411-416
Summary The elements of the VLF chorus, observed simultaneously at a ground station and satellite in polar orbit, can be used to determine the differences in the arrival times of waves and their dependence on latitude. Mostly does not change practically over a wide range of latitudes, however, in some cases it may increase appreciably at low value of L. Model computations of the propagation time, based on the assumption that the source of the chorus is located close to the equatorial plane, have indicated the possibility of explaining the increase in at low latitudes by the presence of a step in the electron density profile close to this plane.
a¶rt;u m a u a um nmu nun um nm n¶rt;um amu u nu¶rt;a ma a u u um auum (L). um a a m ¶rt;uana um, m a a¶rt;am aum uu a a L-a. am anmau n¶rt;nuu amua umua naam m um uu a uu uma auu mnu an¶rt;uu m mauu amua nmu.相似文献
928.
Summary The paper deals with a comparison of two models used in determining the heat flow qM at the lower boundary of two-dimensional geothermal models of the Earth's crust. Method I is based on a linear relationship between the component of the surface heat flow, which is not generated by heat sources inside the model, and the heat flow qM. This method uses a regularization process, in which the variation of the sought function qM is limited from above. Method II is the most frequently used iterative method, in which the (i + 1)-th approximation of qM is determined from the surface heat flow, corresponding to the i-th approximation of qM used as a boundary condition in solving the direct problem. The comparison of both methods has revealed that the solution obtained by method I satisfies the supposed reality better than the solution obtained by method II. Method II is attractive especially for its simplicity. To eliminate the local variations of the estimated heat flow qM, which are due to automatic transmission from the surface heat flow, a combination of method II with some smoothing procedure could be applied.
¶rt;am ¶rt;a m¶rt;a uu mn nma qM a uau ¶rt; muu ¶rt; . m¶rt; unm u ¶rt; ma nm nma, ma uaa umuau mna mu ¶rt;u, u nm qM. m m¶rt; nu n uauu, auuau auau u uu qM . m m¶rt;, mu nm ¶rt; u n a , umau: (i + 1)-a annuau nma qM um n auma nm nma, ma i- annuauu qM. au ¶rt;m, m nm qM, a¶rt; n m¶rt;, mam n¶rt;naa ¶rt;mummu , u, n m m¶rt;. m m¶rt; nuam nmm. ¶rt; mau a auau a¶rt; nma qM, uu ¶rt;mu amamu na u auau nm nma, ¶rt;a uuam au-u¶rt; m¶rt; auau.相似文献
929.
Jaroslav Kubík Vladimír Čermák Reviewer A. Janáčková 《Studia Geophysica et Geodaetica》1986,30(4):376-393
Summary The area of the Upper Silesian Coal Basin was characterized by generally high heat flow ranging from 60 to 120 mWm–2, mean 82±16 mWm–2, which has been difficult to explain. Therefore all published data on the heat flow in this region (n=37) were summarized and re-evaluated. Special attention was paid to the detailed assessment of the lithological structure and the contribution of the individual rock types to the characteristic in-situ thermal conductivity. Also the thermal conductivity of the coal bearing layers was estimated and its effect on the temperature-depth distribution was investigated. The application of the data obtained for the representative thermal conductivity profiles of the whole drilled section considerably reduced the mean heat flow to 70±8 mWm–2. The latter value is fully compatible with the tectonic structure of the northern part of the Carpathian Frontal Foredeep. Slightly increased geothermal activity compared with the heat flow field of the adjacent part of the Bohemian Massif corresponds to certain deep geological rejuvenation during the creation of the Western Carpathians.
a -uu aa aamum nu uuau mn nma (m 60 ¶rt; 120 m.–2 nu ¶rt; 82±16 m. –2), m ¶rt;a ¶rt u. m u u nm a nua ¶rt;a mn nma (n=37) ¶rt; ¶rt;a ua. ua ¶rt; ¶rt;ma aau umuu aa u u mnn¶rt;mu in situ ¶rt; a¶rt; muna n¶rt;. a a mnn¶rt;m m, a ma, a ma u¶rt;aa an¶rt;u mnam nu. nau n mam ¶rt; nuau mnn¶rt;mu m u amu aa nu am uum ¶rt;u mn nm ¶rt; 70±8 m.–2. a uua n mam mmu u amu anam a nua. m uumu amumu n au mn n nuaa amu aua mmmmuuau amuuauu nu uauu um ana¶rdt; anam.相似文献
930.
auau¶rt;u mu uam nua u mau a¶rt; ¶rt;a a au. a¶rt;a n¶rt;amm mau u mau, m mumu mu, a¶rt;a u aua n mana, nuam a man uu ¶rt;unuu aua ¶rt;uam (ma mum). u m umam mamumuu ma u a nma u u n¶rt;¶rt;u man. am ma au n¶rt; na ma¶rt;am n auau. 相似文献