全文获取类型
收费全文 | 46篇 |
免费 | 7篇 |
国内免费 | 12篇 |
专业分类
测绘学 | 3篇 |
大气科学 | 1篇 |
地球物理 | 18篇 |
地质学 | 30篇 |
海洋学 | 2篇 |
天文学 | 5篇 |
综合类 | 4篇 |
自然地理 | 2篇 |
出版年
2013年 | 1篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2006年 | 2篇 |
2005年 | 7篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1964年 | 1篇 |
1959年 | 2篇 |
1955年 | 2篇 |
1948年 | 1篇 |
1932年 | 1篇 |
排序方式: 共有65条查询结果,搜索用时 15 毫秒
1.
Ohne Zusammenfassung 相似文献
2.
Introduction Earthquake magnitude is the most common measure of an earthquake′s size,and is one of the basic parameters of an earthquake.There are three most familiar scales of earthquake magnitude:ML(local earthquake magnitude),MS(surface wave magnitude)and mB/mb(body wave magni-tude).Richter(1935)introduced ML when studying earthquakes in Southern California.In1945,Gutenberg(1945a)put forward surface wave magnitude scale to determine earthquake magnitude(MS)using surface waves(20s)of s… 相似文献
3.
Bubnoff und R. Brinkmann 《International Journal of Earth Sciences》1932,23(3-4):239
Ohne Zusammenfassung 相似文献
4.
5.
The diverse clam shrimp Nestoria-Keratestheria fauna is widely distributed in the Dabeigou Formation in northern Hebei and eastern Inner Mongolia of China.Its important component genus Magumbonia from the Dabeigou Formation in the Luanping Basin,northern Hebei,China,is revised on the basis of a scanning electron microscope (SEM) examination of the type species M.jingshangensis Wang,1984,which revealed morphological features not recognized previously.These include coarse reticulation on the umbo and promi... 相似文献
6.
ZHANG Chengjun ZHENG Mianping Alexander PROKOPENKO Steffen MISCHKE GOU Xiaohui YANG Qili ZHANG Wanyi FENG Zhaodong 《《地质学报》英文版》2009,83(6):1101-1115
Abstract: The Early Holocene paleoclimate in Bosten Lake on the northern margin of the Tarim Basin, southern Xinjiang, is reconstructed through an analysis of a 953 cm long core (BSTC2000) taken from Bosten Lake. Multiple proxies of this core, including the mineral components of carbonate, carbonate content, stable isotopic compositions of carbonate, Ca/Sr, TOC and C/N and C/S of organic matter, are used to reconstruct the climatic change since 8500 a B.P. The chronology model is made by nine AMS 14C ages of leaves, seeds and organic matter contained in two parallel cores. The climate was cold and wet during 8500 to 8100 a B.P. Temperature increased from 8100 to 6400 a B.P., the climate was warm and humid, and the lake expanded. The lake level was highest during this stage. Then from 6400 to 5100 a B.P., the climate became cold and the lake level decreased slightly. During the late mid-Holocene, the climate was hot and dry from 5100 to 3100 a B.P., but there was a short cold period during 4400 to 3800 a B.P. At this temporal interval, a mass of ice and snow melting water supplied the lake at the early time and made the lake level rise. The second highest lake level stage occurred during 5200 to 3800 a B.P. The climate was cool and wet during 3100 to 2200 a B.P., when the lake expanded with decreasing evaporation. The lake had the last short-term high level during 3100 to 2800 a B.P. After this short high lake level period, the lake shrank because of the long-term lower temperature and reduced water supply. From 2200 to 1200 a B.P., the climate was hot and dry, and the lake shrank greatly. Although the temperature decreased somewhat from 1200 a B.P. to the present, the climate was warm and dry. The lake level began to rise a little again, but it did not reach the river bed altitude of the Konqi River, an outflow river of the Bosten Lake. 相似文献
7.
Nicolas Thomas 《紫金山天文台台刊》1996,(3)
Amajor objective of the Infrared Space Observatory (ISO) is the determination of the sized and albedoes of several objects in the "Kuiper disc".The method by which this will be achieved is described.It is shown that the unknown shapes and surface thermal properties proviede additional complications to the interpretation of ISO data.The requirement for ground-based measurements of the visual light curves of these objects is demonstrated and the implications of the results of the ISO observ Vations is discussed. 相似文献
8.
VELOCITY FIELD AND RESISTANCE OF FLOW OVER ROUGH SURFACES WITH LARGE AND SMALL RELATIVE SUBMERGENCE 总被引:1,自引:0,他引:1
Andreas DITTRICH Institut fuer Wasserbau und Kulturtechnik Universitet Karlsruhe Kaiserstr. Karlsruhe Germany Katinka KOLL Institut fuer Wasserbau und Kulturtechnik Universitet Karlsruhe Kaiserstr. Karlsruhe Germany 《国际泥沙研究》1997,(3)
LINTRODUCTIONPreciseknowledgeofthevelocityfieldandthecorrespondingresistanceofflowoverrollghsurfacesareofgreatimportanceformanypracticalproblemssuchastheestimationofthestabilitVofbedmaterialinerosiveriversortheremovalofaccumulatedfinesedimentfromthechannelandthelooseningofgravelbedmaterialbycontrolledreleaseofreservoirwater.Thelatterprocedure,calledflushingflows,isfrequentlyspecifiedtorestoreortomaintainaquatichabitat(WILCOCKetal.,1996).Dependingonwaterdepthhandroughnessheightk.(=equiv… 相似文献
9.
Chongjiang DU Dr. Institute for Hydraulic Structures Agricultural Engineering University of Karlsruhe Kaiserstr. D- Karlsruhe Germany Franz NESTMANN Prof Dr. Institute for Hydraulic Structures Agricultural Engineering University of 《国际泥沙研究》1997,(3)
LINTRODUCTIONTerrainmodellingisatermtodescribetheprocessofrepresentingthesurfaceoftheEarth.Mathemahcally,theproblemcanbedescribedas;Givenasetofn(3sn相似文献
10.
准噶尔盆地头屯河地区侏罗系陆相层序包含4种沉积:(1)冲积扇平原湿地中的砾石质河流沉积(八遭湾组),其特征提示在湿地中发育了规模不同的大河道(深3—5m,宽1OOm左右)及较小的分流或决口河道(深2m以下,宽6—30m)。(2)沙质低弯度河沉积,晚三工河、早西山窑、头屯河及齐古组沉积期的河流沉积属之。其特点是河道相与河间相间的界线清楚,提示河道在某一段时期固定于平原的特定地带;河道规模受古气候和构造的制约;气候干旱化和构造抬升(如头屯河组沉积时期),侵蚀基面降低,河流动力增加,因而河流规模变大,反之变小;晚头屯河组沉积期的干旱气候存在暂时性河道。(3)三角洲前缘沉积(河口中坝),见于八道湾、三工河及喀拉扎组中。(4)开阔湖相沉积,以三工河组厚的页岩层序为代表。 砂岩成分逆向反映源区剥蚀顺序。下侏罗统富含泥质岩屑,表示天山上古生界浅变质及沉积层系被剥蚀。自下而上,碎屑中稳定矿物增加,粒度变细,反映源区由于剥蚀而后退。中—上侏罗统砂岩成分演化方向不同于下侏罗统,可能与三工河组沉积末期盆地边缘构造回春有关。在Q-F-L三角图中,侏罗系样品大都落在构造区之间,反映陆相盆地充填物的混合来源。下—中侏罗统的煤既有原地生成,亦有重要的他生类型。 相似文献