全文获取类型
收费全文 | 2427篇 |
免费 | 73篇 |
国内免费 | 14篇 |
专业分类
测绘学 | 57篇 |
大气科学 | 160篇 |
地球物理 | 1250篇 |
地质学 | 551篇 |
海洋学 | 43篇 |
天文学 | 385篇 |
综合类 | 6篇 |
自然地理 | 62篇 |
出版年
2021年 | 35篇 |
2020年 | 37篇 |
2019年 | 32篇 |
2018年 | 60篇 |
2017年 | 74篇 |
2016年 | 90篇 |
2015年 | 85篇 |
2014年 | 91篇 |
2013年 | 100篇 |
2012年 | 60篇 |
2011年 | 73篇 |
2010年 | 78篇 |
2009年 | 81篇 |
2008年 | 60篇 |
2007年 | 61篇 |
2006年 | 64篇 |
2005年 | 33篇 |
2004年 | 43篇 |
2003年 | 40篇 |
2002年 | 45篇 |
2001年 | 40篇 |
2000年 | 42篇 |
1999年 | 33篇 |
1998年 | 36篇 |
1997年 | 27篇 |
1996年 | 42篇 |
1995年 | 24篇 |
1994年 | 32篇 |
1993年 | 30篇 |
1992年 | 31篇 |
1991年 | 45篇 |
1990年 | 30篇 |
1989年 | 51篇 |
1988年 | 37篇 |
1987年 | 43篇 |
1986年 | 42篇 |
1985年 | 27篇 |
1984年 | 37篇 |
1983年 | 37篇 |
1982年 | 39篇 |
1981年 | 29篇 |
1980年 | 32篇 |
1979年 | 44篇 |
1978年 | 38篇 |
1977年 | 29篇 |
1975年 | 24篇 |
1974年 | 32篇 |
1973年 | 29篇 |
1972年 | 28篇 |
1971年 | 30篇 |
排序方式: 共有2514条查询结果,搜索用时 48 毫秒
91.
Fault interaction and seismicity: Laboratory investigation and its seismotectonic interpretation 总被引:2,自引:0,他引:2
Systems of two parallel linear faults of the same length with the angle of inclination =45° were investigated under uniaxial linearly increasing load. Perspex plates were used as models. For each treated fault configuration the morphology of tensile cracks and the sequence of seismoacoustic events of shear and tensile origin were studied.It is shown that the seismic regime of a fault system is strongly influenced by the contact conditions on a fault plane; it is different in the faults with the aseismic contact, represented by open slits, and in the faults with the seismoactive contact, represented by filled slits, respectively.The experiments proved the dominating role of a fast shear displacement of the stick-slip type in the regime of seismic energy release of a fault system. The tensile crack generation seems to be only of little—if not negligible—importance. On the other hand, the existence of tensile cracks in a fault system can play an important role in the course of subsequent loading cycles because the stick-slip displacements can take place not only along the primary faults but also along the planes of tensile cracks.A comparison of some results of model experiments and the already published results of geological and seismological investigations indicated that the way of seismic energy relase on faults in nature and in the laboratory could be of the same character. Several analogies between the seismic regime of a fault model and of real seismic regions were found concerning the morphology of faults, off-fault fore- and aftershocks, and earthquake doublets, respectively. 相似文献
92.
V. Slde
ek 《洁净——土壤、空气、水》1986,14(5):555-566
There is given a list of 323 taxa of freshwater diatoms occurring in waters of Central Europe. Each taxon is characterized by 10 balls of saprobic valence, the indicative weight of species (Ii) and by the individual saprobic index (Si) indicating its position on a conventional scale of saprobity. Diatoms are very common aquatic organisms, but are only medium or bad indicators of saprobity, because their saprobic valence is usually wide. 相似文献
93.
94.
Milan Burša 《Studia Geophysica et Geodaetica》1995,39(1):1-10
Summary The positions of the Lagrangian points of the Pluto-Charon system have been determined using the orthogonal system of cofocal ellipses-hyperbolas, the foci being situated at the centre of mass of the bodies. The tidal distortions of Pluto amount to 30 m, those of charon to 122 m. The tidal forces are believed to influence the figures of the bodies significantly. 相似文献
95.
Summary The total ozone response to strong major geomagnetic storms (Ap≥60) in winter along the 50° N latitudinal circle is studied. The results add to the recent results of Laštovička et al. (1992)
obtained for European middle latitudes (∼50°N) and to the results of Mlch (1994). A significant response of total ozone is
only observed in winter under high solar activity/E-phase of QBO conditions (E-max) and seems to be caused by geomagnetic
storm-induced changes of atmospheric dynamics. There are two sectors along latitude 50°N, which are sensitive to forcing by
geomagnetic storms both in total ozone and the troposphere — north-eastern Atlantic-European and eastern Siberia-Aleutian
sectors. The total ozone response under E-max conditions manifests itself mainly as a large decrease in the longitudinal variation
of ozone after the storm, which means an increase of ozone in Europe. The observed effects in total ozone consist in redistribution,
not production or loss of ozone. 相似文献
96.
Summary The effect of the IMF sector boundary crossing (IMF SBC) in the vorticity area index (VAI) — the well-known dip in the VAI after IMF SBC — is found to be independent of the IMF SBC effect in the cosmic ray flux. This finding refutes a recent suggestion by Lundstedt [1] that the IMF SBC effect in VAI is caused by a decrease in cosmic ray flux, but supports the concept of the IMF SBC effects in the ionosphere and atmosphere developed by Latovika [2–4]. Cosmic rays seem to affect the troposphere in another way.
¶rt;mu nu mau nam aum n ( ) a u¶rt; na¶rt;u aumu () — um uu n — a¶rt; auu m ma nm uu . mm mam nam ¶rt;a n¶rt;u ¶rt;m¶rt;a [1], m m a nuu nma uu , n¶rt;¶rt;uam nu m u u am, aum amu [2–4]. am m uu u m um a mn ¶rt;u a.相似文献
97.
Marcela Laštovičková Y. V. Ramana B. S. Gogte Reviewer A. Janáčková 《Studia Geophysica et Geodaetica》1987,31(1):60-72
Summary Results on electrical conductivity, chemical analysis and age of the rock samples from the Indian Subcontinent are presented. The old Precambrian Indian rocks tend to be less conductive than characteristic rocks of crustal and upper mantle structures.
nuam mam uu mnm¶rt;mu, uu aaua u n¶rt;u u uu n¶rt; u ¶rt;uu. ma nauu n¶rt; u ¶rt;uu naam mn¶rt;m aamumuu n¶rt; u amuu.相似文献
98.
Erhard Wielandt Andreas Sigg Axel Plešinger Josef Horálek Reviewer K. Pěč 《Studia Geophysica et Geodaetica》1987,31(1):1-7
Summary Phase velocities of Rayleigh and Love waves have been measured between the broadband seismic stations KHC (Kaperské Hory, South Bohemia) and KSP (Ksi, Lower Silesia), a profile that nearly coincides with the Interactional DSS Profile VII. The data for both wave types were separately inverted into models of shear-wave velocity versus depth. Novotný's model KHKS 82[1] for the DSS Profile VII was used as a start model. While the crustal section of Novotný's model is compatible with both of our data sets, our Rayleigh-wave data require smaller shear-wave velocities, on the average by 0.24 km/s, in the top 180 km of the mantle. The average difference between Novotný's model and our Love-wave model in that depth range is only 0.06 km/s. If our identification of the observed Love waves as the fundamental mode is correct, this result indicates the presence of polarization anisotropy in the uppermost mantle.
u a mu u a ¶rt; unu uuu mauu (an , a u) u S (, ua uu). u - S nuuum mmmm ¶rt;a¶rt; nu VII . a ¶rt; u mun m¶rt; umua ¶rt;u auumu mu nn mu. am mam¶rt;u a unaa ¶rt; S 82 m[1] ¶rt; nu VII . a am ¶rt;u m aua uu aau au ¶rt;a, ¶rt;a au ¶rt;a ¶rt; mm uu m nn — ¶rt; a 0,24 / 180 uma amuu. ¶rt;a aua ¶rt; ¶rt; m u a ¶rt; ¶rt; a m ¶rt;uanau n¶rt;mam 0,06 /. u aa u¶rt;muuau a¶rt;a a a ¶rt;ama ¶rt;a m nau, m mm mam u¶rt;ummm numuu nuau aumnuu amuu.相似文献
99.
Vladislav Babuška Jaroslava Plomerová Edelvays Spasov Reviewer J. Janský 《Studia Geophysica et Geodaetica》1987,31(3):266-283
Summary Teleseismic P residuals calculated for waves arriving from various azimuths and angles of incidence, and a 3-D inversion of the residuals provided the basis for characterizing the uppermost mantle structure beneath Bulgaria. The Moesian Platform and the Rhodopean Massif are two different blocks characterized by a lithosphere thickness of about 130–140 km with a zone of lithosphere thinning along their contact. Both units have opposite patterns of the directional dependence of relatively high and low P velocities. This directional dependence is interpreted by dipping anisotropic structures in the subcrustal lithosphere, which probably represent remnants of paleosubductions of an old oceanic lithosphere.
auma u nu¶rt;u n¶rt; au aumau u au. a uu mu ¶rt;am ¶rt; aamuauu mm amuu n¶rt; au. uua nama u ¶rt;nu au, ¶rt;a au a mu um nuuum 130–140 ¶rt; uma m ¶rt; u mama. a a aamua nmun ana auum mum u u mu . ma anaa auum umnmuaa a nu aumn mm amu. mu mm n¶rt;maum a mamu na¶rt;u ma au um.相似文献
100.
V. Slde
ek 《洁净——土壤、空气、水》1987,15(6):658-658