全文获取类型
收费全文 | 1918篇 |
免费 | 48篇 |
国内免费 | 6篇 |
专业分类
测绘学 | 57篇 |
大气科学 | 44篇 |
地球物理 | 819篇 |
地质学 | 542篇 |
海洋学 | 30篇 |
天文学 | 384篇 |
综合类 | 5篇 |
自然地理 | 91篇 |
出版年
2021年 | 17篇 |
2020年 | 19篇 |
2019年 | 21篇 |
2018年 | 66篇 |
2017年 | 50篇 |
2016年 | 86篇 |
2015年 | 56篇 |
2014年 | 78篇 |
2013年 | 88篇 |
2012年 | 77篇 |
2011年 | 76篇 |
2010年 | 77篇 |
2009年 | 71篇 |
2008年 | 54篇 |
2007年 | 62篇 |
2006年 | 47篇 |
2005年 | 37篇 |
2004年 | 40篇 |
2003年 | 45篇 |
2002年 | 39篇 |
2001年 | 29篇 |
2000年 | 29篇 |
1999年 | 22篇 |
1998年 | 19篇 |
1997年 | 22篇 |
1996年 | 23篇 |
1995年 | 21篇 |
1994年 | 22篇 |
1993年 | 23篇 |
1992年 | 18篇 |
1989年 | 23篇 |
1988年 | 20篇 |
1987年 | 25篇 |
1986年 | 27篇 |
1985年 | 25篇 |
1984年 | 29篇 |
1983年 | 29篇 |
1982年 | 28篇 |
1981年 | 26篇 |
1980年 | 26篇 |
1979年 | 26篇 |
1978年 | 29篇 |
1977年 | 21篇 |
1976年 | 19篇 |
1975年 | 24篇 |
1973年 | 20篇 |
1972年 | 21篇 |
1971年 | 36篇 |
1969年 | 16篇 |
1968年 | 22篇 |
排序方式: 共有1972条查询结果,搜索用时 62 毫秒
81.
Zdeněk Šimon Jan Kostelecký Antonín Zeman Reviewer L. Skalský 《Studia Geophysica et Geodaetica》1988,32(1):16-23
Summary It is recommended that the data from measurements with supraconducting gravity meters be also analysed with regard to verifying the gravitation absorption hypothesis. Based on theoretical data from a3-year period, the spectrum of the assumed effect of shielding the gravitational influence of the Sun by the Earth's body on the value of the acceleration of gravity has been calculated for the tidal station Brussels (Figs 2a–e).
¶rt;aam aauuam ¶rt;a uu n¶rt;uaumau ma mu u nuunm n¶rt;auaumauu. a mmuu ¶rt;a a mmu nu¶rt; u nm n¶rt;naa ma auauaumau ¶rt;mu a m a uu u u mmu ¶rt; nuu mauu (u. 2a–).相似文献
82.
83.
P. Daněk 《GeoJournal》1993,30(3):249-254
In the 1991 population census, 1.4 million inhabitants of the Czech Republic applied for Moravian or Silesian nationality, which did not exist before.They expressed their consciousness of territorial appurtenance to the historical provinces of Moravia and Silesia and by this declaration they set it above the appurtenance to the Czech nation. New social cleavage thus developed in ethnically almost homogeneous environment of the Czech Republic, which constitutes a potential threat of the further splitting of the State. Trying to find the causes of such a phenomenon, the author deals with the territorial differentiation of these inhabitants and factors which influenced it. The close interconnection with political demands is stressed. The insensive centralizing measures of the communist regime are considered as the direct impulses of the present development. The phenomenon is understood as a specific manifestation of the posttotalitarian social crisis in Central and Eastern Europe. 相似文献
84.
Jaroslav Kubík 《Studia Geophysica et Geodaetica》1990,34(2):110-128
Summary On the basis of temperature measurements in 190 boreholes we constructed a map of temperature distribution at a depth of 100
m below the terrain level and maps of temperature gradients in different depth intervals below the Earth's surface in the
territory of the Bohemian Massif. Investigations were made into the effects of hydrogeological, geomorphological, structure
geological and microclimatic factors on the subsurface temperature field in the Bohemian Massif together with an assessment
of effects of these factors on heat flow determinations in shallow boreholes 100 – 200 m deep.
Резюме Нa основaнuu uзмеренuя mемnерamуры в 190 сквaжuнaх былa nосmроенa кaрma рaсnре?rt;еленuя mемnерamуры нa ?rt;лубuне 100 м nо?rt; nоверхносmью Землu u кaрmы ?rt;рa?rt;uенma mемnерamуры в рaзных nо?rt;nоверхносmных uнmервaлaх нa mеррumорuu Чешско?rt;о мaссuвa. Иссле?rt;овaлось осложненuе mеnлово?rt;о nоля у nоверхносmu Землu целым ря?rt;ом фaкmоров: эффекmы рельефa nоверхносmu Землu, ?rt;вuженuя nо?rt;земных во?rt;, mеnлоnрово?rt;носmu ?rt;орных nоро?rt;, мuкроклuмamuческuе эффекmы u ?rt;р. u влuянuе эmuх фaкmоров нa uзмеренuе mеnлово?rt;о nоmокa в не?rt;лубокuх сквaжuнaх (100 – 200 м).相似文献
85.
Summary The paper is intended as a contribution to the quantitative analysis of travel-time curves of seismic events recorded in the Ostrava-Karviná District (OKD). The input data represent a set of 2621 seismic events, recorded by the local seismological network of 26 mine stations DSLA and a regional diagnostic polygon consisting of five surface Lennartz stations. All the events were processed automatically in the Operational Seismological Centre of the Czechoslovak Army Mine in Karviná and stored in the seismological data base. The results are presented in the form of graphs of arrival times versus distance for the whole OKD, for two mines and one tectonic block.Travel-time curves of direct P and S waves, as well as of reflected and refracted waves are given. The direct P and S waves propagate well practically throughout the whole region studied, but their apparent velocities of propagation are affected by the properties of the rock medium.As a result of the complicated geological conditions, the recorded wave image is quite complicated. Methods of mathematical modelling, using kinematic and dynamic parameters of seismic waves, will have to be applied to identify the separate wave groups uniquely. 相似文献
86.
Summary A general analytical model for travel times of seismic waves propagating in a radially asymmetric Earth, is suggested. It is represented by a series of irreducible spherical tensor products with bipolar spherical coefficients. The main term of the series describes the travel times in a radially symmetric Earth, the others represent corrections due to the spherical assymmetry. The method of least squares is suggested for determining the bipolar spherical coefficients from observed seismic travel times. Since the proposed theory assumes that the analytical representation is related to the reference earth, the corrections to the non-zero focal depth and non-zero sea-level height of the seismographic station must be introduced.
aamuam a aaumua ¶rt; ¶rt;¶rt;aa uu a¶rt;ua ¶rt;¶rt; . mm¶rt;a aam u¶rt; ¶rt;a n¶rt;u m unu uuu uumau. ¶rt;a nuam¶rt;a a¶rt;ua ¶rt;¶rt; . ¶rt;u m aam nna a m a¶rt;ua ¶rt;¶rt;mu. ¶rt;aam un uu uum ¶rt; a¶rt;a¶rt;aa a¶rt;um m¶rt; auu a¶rt;am. ¶rt;aaa mu u¶rt;um u n¶rt;nu -unu¶rt;a u. nuam n ¶rt;u nna n¶rt;mau¶rt;aa, a uu aa u m nm a¶rt;u.相似文献
87.
Summary Four fundamental forms of expansion of the double product of the gravity function into an infinite series are derived. Two isotropic parts are separated, one is expressed by Legendre polynomials and the other by invariants of Wigner's D-matrices.
¶rt; m n¶rt;mau ¶rt; au ¶rt; nu¶rt;uaumau uu ¶rt;. ¶rt; ¶rt; umn amu, na aam n nu a¶rt;a u ma n uauam amu ua.相似文献
88.
Summary The measuring systems of Askania gravity meters are assumed to have 3 degrees of freedom. The axis of rotation of the beam can also be displaced in the vertical and horizontal directions. The equations of equilibrium of this system (25)–(27) were used to derive the expressions for the effect of displacing the calibration ball, for the scale equation and for the sensitivity of the gravity meter. Equations (33), (34) and (39) refer to gravity meters with a photoelectric transducer, and Eqs (46), (47) and (49) to gravity meters with a capacitive transducer.
uum umaum au n¶rt;naam 3 mnu ¶rt;. au aa m m nam mua uuma anau. au au m um (25)–(27) ¶rt; au ¶rt; ¶rt;mu nu au aua, ¶rt; aua a u ¶rt; mummuauma. aum mmuu mm m au (33), (34), (39), ¶rt;aum m mm au (46), (47), (49).相似文献
89.
Calibrating functions play a substantial role in the determination of earthquake magnitudes. Their shape and character is closely connected with the internal structure of the Earth, the distribution of velocities and attenuation of seismic waves in the Earth's body. These facts have been considered during the establishment of the Eurasian Homogeneous Magnitude System (EuHMS). The paper summarizes the procedures used for constructing the new complete set of calibrating functions for body and surface waves (vertical and horizontal components of P, S and L waves from medium period instruments, and vertical component of P waves from short period instruments).The calibrating functions were derived in the distance range between 20° and 100°, being based on several thousands of homogeneous observations for each wave type. The application of a HMS gives a possibility to derive the magnitude calibrating functions with a considerable degree of reliability due to the method of simultaneous optimization of the calibrating functions and the systems of station corrections. The magnitude calibrating functions for EuHMS represent the first complete set of calibrating functions, which are derived by the same standard method and initial observational material. A comparison with the existing calibrating functions shows that the application of σ and Q functions, presently used in the seismological practice for magnitude determinations, may lead to errors exceeding
of magnitude unit at certain epicentral distances, specific for each wave type. It appears that the internationally recommended Q functions are not admissible for magnitude determinations from short-period P waves. 相似文献
90.
Summary The morphology of the Wadati-Benioff zone in the region of Southern Kuriles and Hokkaido, based on the distribution of 4015 earthquake foci, verified the existence of an intermediate depth aseismic gap and its relation to active andesitic volcanism. A paleosubduction zone activated by an intermediate depth collision with the active subduction zone was found and described.
u Wadati-Benioff amu uu - u a¶rt;, aa a an¶rt;uu 4015 a mu, nm¶rt;ua mau n¶rt; au u amu a¶rt;um au. a a¶rt;a u nuaa a na¶rt;uu, amuuuaa nmu mu amu ¶rt;uu.相似文献