全文获取类型
收费全文 | 307篇 |
免费 | 11篇 |
专业分类
测绘学 | 9篇 |
大气科学 | 14篇 |
地球物理 | 133篇 |
地质学 | 105篇 |
海洋学 | 19篇 |
天文学 | 22篇 |
自然地理 | 16篇 |
出版年
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 15篇 |
2013年 | 16篇 |
2012年 | 13篇 |
2011年 | 7篇 |
2010年 | 9篇 |
2009年 | 11篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 11篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1991年 | 4篇 |
1990年 | 9篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1974年 | 4篇 |
1967年 | 3篇 |
1966年 | 4篇 |
1965年 | 4篇 |
1959年 | 2篇 |
1958年 | 4篇 |
1957年 | 5篇 |
1956年 | 2篇 |
1954年 | 5篇 |
1953年 | 2篇 |
1950年 | 3篇 |
1940年 | 3篇 |
排序方式: 共有318条查询结果,搜索用时 15 毫秒
91.
92.
93.
Dietrich Werner 《Tectonophysics》1985,121(1):97-108
An attempt has been made to model the temperature distribution taking into account simultaneously the effects of regional uplift and erosion, present topography, development of topography with time and paleoclimatic variations.Two time intervals were considered: a long period (30 m.y.) for the uplift history and a relatively short period (200,000 y) for the surface history (topography, climate).The calculations were based on finite differences in space and time. An example is presented for an area in the Swiss Alps, where observed rock temperatures in a tunnel and paleotemperature data are available. A simple uplift history can fit the paleotemperatures but leads to unrealistic high temperatures in greater depths. To improve the model frictional heat sources due to crustal overthrusting were introduced. 相似文献
94.
95.
In landscape diagnosis landscapes are evaluated on the basis of their natural and technological characteristics with regard to the possibilities and risks of intensive utilization. Land use is an essential criterion for the evaluation of the condition of landscapes. Remote sensing will allow for an analysis of large areas with regard to land use. Landscape diagnosis through satellite photographs will be illustrated in two examples. In the first one multitemporal evaluation of satellite photographs is discussed with particular reference to attempts made to characterize the utilization of landscape potentials. In the second example attempts have been made to classify medium-sized landscape units by satellite photographs, with additional characterization through thematic maps based on the Atlas GDR. 相似文献
96.
The Sun's limb darkening was observed repeatedly between the 1986 minimum and the 1990 maximum of solar activity.Systematic variations, which could depend either on the momentary activity and/or the phase in the solar cycle, werenot detectable, either at continuum wavelengths or in two broad-band spectral intervals. Completelyirregular variations, which concern not only individual, successive scans (due to granulation, etc.), but also thedaily andseasonal averages, are usually less than 1%, but can reach occasionally 2% or even more. Minoreast-west asymmetries even in the seasonal means seem to be well established, mainly for < 400 nm. Thefinal, mean limb-darkening coefficients agree basically with those published by Pierce and Slaughter (1977) and Pierce, Slaughter, and Weinberger (1977), but show a much lower scatter when plotted against wavelength. 相似文献
97.
Martin Gude Gerhard Daut Susanne Dietrich Roland Mäusbacher Christer Jonasson Annett Bartsch & Dieter Scherer 《Geografiska Annaler: Series A, Physical Geography》2002,84(3-4):205-212
The analysis of Holocene geomorphic process activity demands long–term data sets, which are available for the Kärkevagge catchment due to 50 years of intensive geomorphologic field studies. This data set is used in combination with additional field measurements, remote sensing and digital elevation model (DEM) analysis to provide input data for modelling Holocene valley development. On the basis of this information, geomorphic process units (GPUs) are defined by means of GIS modelling. These units represent areas of homogeneous process composition that transfer sediments. Since the data base enables the quantification of single processes, the interaction of processes within the units can also be quantified. Applying this concept permits calculation of recent sediment transfer rates and hence leads to a better understanding of actual geomorphic landscape development activity. To extrapolate these data in time and space the process–related sediments in the valley are analysed for depth and total volume, primarily using geophysical methods. In this fashion the validity of measured process rates is evaluated for the Holocene time scale. Results from this analysis are exemplified in a cross–profile showing some of the principal sediment units in the valley. For example, the measured modern rates on a slush torrent debris fan seem to represent the Holocene mean rate. This approach should also be suitable for revealing Holocene geomorphic landscape development in terms of climate change. 相似文献
98.
Stéphane Gaffet Giovanna Cultrera Michel Dietrich Françoise Courboulex Fabrizio Marra Michel Bouchon Arrigo Caserta Cécile Cornou Anne Deschamps Jean-Paul Glot Robert Guiguet 《Journal of Seismology》2000,4(4):525-541
Strong site effects were observed during the two M
W 5.7 and M
W 6.0 main shocks of the Colfiorito seismic crisis which occured on September 26, 1997 in Umbria-Marche (Central Italy).The most obvious indications of these effects are the dramatic differences in damage shown by buildings of similar construction in neighboring villages.Such observations were specifically made in the Verchiano valley in the fault area, 15 km south of Colfiorito where the Verchiano village and the Colle and Camino hamlets were heavily damaged (MCS intensity IX-X) since the first main shock of 1997/09/26,while in contrast, the Curasci village located 2 km eastwards remains almost intact.In order to study the anomalous ground motion amplifications in this area, an array of 11, 3-components seismo- and accelero-meters was set up during the 1997/10/20-24 period, extending from the western side of the valley, up to the top of Mount San Salvatore, going accross the Colle and Curasci hamlets.During the experiment, 67 aftershocks enlightened the valley from the Colfiorito (10 km north) and the Sellano (6 km south) active swarms.Seismic refraction experiments were conducted at the same time in the 500 m wide, 1500 m long Verchiano valley in order to determine the thickness and main characteristics of the alluvial infilling.The main results are: (i) compared to the valley side ground motion, and for all the events, recordings in the central part of the valley (piana di Verchiano) show relative amplification of 10 with a clear lengthening of the seismogram duration by a factor of 2 – (ii) broad band relative amplification of 6–8 is also clearly identified at the top of the Mount San Salvatore overhanging the valley – (iii) any of the site effect measurements done explains by itself the strongly contrasted damage observed at Colle and Curasci: i.e. the modification of the near-field radiation pattern by interaction with the free heterogeneous surface may have induced local shadow zones that saved Curasci. 相似文献
99.
Dietrich Soyez 《GeoJournal》2000,52(1):7-16
Dial locally -act globally: this slogan seems to appropriately reflect, under prevailing conditions of globalization and disembeddedness, the seemingly unrestrained possibilities of a variety of actors to influence events - without being present - anywhere on the planet. While focusing on a broadly conceived group of transnational social movement organizations - from non-governmental organizations to loosely linked transnational advocacy networks - the aim of this paper is to give evidence of the fact that geography - and all manner of borders - still matters even for these actors. Despite being linked with the world, they continue to act from deeply embedded local contexts, very often not triggering true transnational interaction but much more limited translocal encounters. In doing so, however, they literally cause collisions between different worlds while not only modifying existing but also constructing new spaces.September 1984 – first week of my field-work on Cape Breton Island, Nova Scotia, eastern Canada. A teacher at the local high school had agreed to make the first contacts with environmental groups, who were opposed to the use of pesticides by a Swedish forest products company. In return, he asked me to give two geography lessons on Germany to his class.After the lessons the 15-year-old pupils asked questions. One of the first of these was what I did with my family on a free weekend. Without long consideration, I answered: ``We often go for a walk in the forest with our children'. The pupils doubled up laughing in response, and the geography teacher was obviously also amused.A few days later I understood the reason for this reaction, when I saw typical forest land in Nova Scotia for the first time. Forests of an age which in Germany would be airy timber forests, which could be walked through even away from paths, were here largely inpenetrable thickets with numerous trunks per square meter not much thicker than an arm. Nobody could `go for a walk' here...This episode serves as a background to the issues that will be discussed, and I will return to it in my conclusion. It supports a central aspect, which is often neglected in many discussions about globalization: geography matters. 相似文献
100.
C. Price Y. Yair A. Mugnai K. Lagouvardos M. C. Llasat S. Michaelides U. Dayan S. Dietrich F. Di Paola E. Galanti L. Garrote N. Harats D. Katsanos M. Kohn V. Kotroni M. Llasat-Botija B. Lynn L. Mediero E. Morin K. Nicolaides S. Rozalis K. Savvidou B. Ziv 《Surveys in Geophysics》2011,32(6):733-751
One of the costliest natural hazards around the globe is flash floods, resulting from localized intense convective precipitation over short periods of time. Since intense convective rainfall (especially over the continents) is well correlated with lightning activity in these storms, a European Union FP6 FLASH project was realized from 2006 to 2010, focusing on using lightning observations to better understand and predict convective storms that result in flash floods. As part of the project, 23 case studies of flash floods in the Mediterranean region were examined. For the analysis of these storms, lightning data were used together with rainfall estimates in order to understand the storms?? development and electrification processes. In addition, these case studies were simulated using mesoscale meteorological models to better understand the local and synoptic conditions leading to such intense and damaging storms. As part of this project, tools for short-term predictions (nowcasts) of intense convection across the Mediterranean and Europe, and long-term forecasts (a few days) of the likelihood of intense convection, were developed and employed. The project also focused on educational outreach through a special Web site http://flashproject.org supplying real-time lightning observations, real-time experimental nowcasts, medium-range weather forecasts and educational materials. While flash floods and intense thunderstorms cannot be prevented, long-range regional lightning networks can supply valuable data, in real time, for warning the public, end-users and stakeholders of imminent intense rainfall and possible flash floods. 相似文献