首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   39篇
  免费   6篇
  国内免费   4篇
测绘学   1篇
大气科学   15篇
地球物理   3篇
地质学   19篇
综合类   7篇
自然地理   4篇
  2022年   2篇
  2021年   1篇
  2020年   2篇
  2018年   1篇
  2017年   3篇
  2016年   1篇
  2013年   1篇
  2009年   3篇
  2008年   10篇
  2007年   5篇
  2006年   1篇
  2004年   9篇
  2003年   3篇
  2002年   2篇
  2001年   1篇
  2000年   1篇
  1999年   2篇
  1992年   1篇
排序方式: 共有49条查询结果,搜索用时 113 毫秒
1.
The lithological-stratigraphic study of volcanogenic-siliceous rocks developed on the left side of the Machtovaya River, a right tributary of the Amur River, yielded the first radiolarian assemblages of the late Late Tithonian, the late Late Tithonian-early Valanginian, and the middle-late Albian age. It is established that the stratigraphic succession of volcanogenic-siliceous rocks in this area is composed of upper Tithonian-Valanginian dark red to red-brown cherts with basalts in the lower part of the section and Albian dark gray clayey cherts, olive-gray siliceous-tuffaceous argillites, and tufaceous siltstones in its upper part. The replacement of cherts by their clayey varieties likely occurred in the Aptian. The composition, structure, and age of these strata and the rocks constituting the Kiselevka-Manoma accretionary complex are different, which indicates their different tectonic origin.  相似文献   
2.
The typification of ferromanganese nodules (FMN) formed in subaqueous and subaerial settings and in residual materials, as well as FMN localization in various sediments and soils, is discussed. The genetic diversity of morphologically similar FMN and the transformation of FMN-bearing complexes with changes in landscapes have been established.  相似文献   
3.
4.
吐鲁番葡萄免土埋越冬技术试验分析   总被引:1,自引:0,他引:1  
以吐鲁番市葡萄乡铁提尔村和红柳河园艺场五队为试验区,在2007-2008年越冬期间,利用白绒胶粘布、黑绒胶粘布、深色再生绒毡、黑色PVC保鲜膜作为覆盖材料,开展葡萄免土埋越冬气象条件研究。结果表明,免土埋覆盖能较好起到保温保湿作用,基本能满足葡萄安全越冬需要。  相似文献   
5.
Magmatic rocks of the Pikan and Un’ya massifs situated in eastern segment of the Mongolian-Okhotsk foldbelt are studied using isotopic-geochronological (U-Pb zircon dating) and geochemical methods. Two rock complexes different in age are recognized in the Pikan massif: the high-Al gabbro-tonalite association of the Middle Ordovician (468 ± Ma) and granodiorite-granite association of the Late Silurian-Early Devonian (415 ± 7 Ma). The Late Ordovician age (454 ± 5 Ma) is established for leucocratic granites of the Un’ya massif. As is suggested, the Pikan and Un’ya massifs are “allogenic blocks” detached from continental framework of the Mongolian-Okhotsk foldbelt and tectonically emplaced into the foldbelt structure at the last stage of its development.  相似文献   
6.
Gold mass transfer with chloride and carbonate-chloride solutions was examined at the 300 and 400°C isotherms and P tot = 1 kbar by means of experimental modeling and theoretical simulations. CO2 was confirmed to suppress Au solubility in fluids. The low Au solubility (mAu < 10?8) determined in the experiments explains the mechanism of its precipitation when serpentinites and listwanites interact with acidic mineralized solutions. Listwanitization, which was genetically related with the emplacement of orogenic granitoids, was determined to have overprinted serpentinites and rodingites and strongly affected Au transport in the oregeochemical system. The characteristics of the metasomatic processes in the Ust’-Dep ophiolites and the gold concentration in the rocks produced by these processes confirm this conclusion.  相似文献   
7.
On the basis of geological observations and the study of conodont and radiolarian microfauna, a new stratigraphic scheme was proposed for the Mesozoic deposits of the Komsomolsk district of the Amur region. The lower Khorpy Group (T2-J3) consists of two units: the Boktor (T2-J2) and Kholvasi (J2–3). The Boktor Sequence (400 m thick) is represented by pelagic cherts with an admixture of cherty-clayey shales and volcanic rocks. The Kholvasi Sequence (500 m thick) is built up of the predominant siltstones and clayey shales with rare intercalations and lenses of clayey cherts and cherty-clayey shales. The upper Komsomolskaya Group (K1) has a terrigenous composition and includes the Gorin, Pionerskaya, and Pivan formations of 5 km total thickness. It is made up of intercalated sandstones, siltstones, mudstones, and often turbidites (proximal to distal). The rocks contain abundant buchia fauna of Volgian-Valanginian age, as well as carbonized plant detritus and flora of the Early Cretaceous habit. The described complex is characterized by a nappe-fold structure typical of the accretionary prisms in the ocean-continent convergence zones. The predominance of the coherent type of accretionary prisms reflects the simple morphology of the oceanic plate.  相似文献   
8.
南京地区葡萄生长发育模拟,品质分析和对策   总被引:2,自引:0,他引:2  
  相似文献   
9.
酿酒葡萄冻害原因的初步分析及防御对策   总被引:5,自引:0,他引:5  
通过对酿酒葡萄冻害的调查研究分析指出:初霜冻的早晚和冬季的极端低温不是造成酿酒葡萄冻害的主要原因。品种间差异和栽培管理不同也不是造成酿酒葡萄冻害的主要原因,10月份的强降温、气温明显偏低(气温≤-5.2℃)才是酿酒葡萄树体冻害的主要原因。引种抗冻能力较强酿酒葡萄品种、选择适应的生长环境和掌握适宜的埋土时间,是防御酿酒葡萄冻害防御的主要对策。  相似文献   
10.
2003年异常气候对清徐葡萄的影响   总被引:1,自引:0,他引:1       下载免费PDF全文
气候对葡萄生长发育的影响十分关键,以光照、温度和降水三要素为主。利用清徐地面气象资料,根据葡萄各生育阶段对气候资源的需求特点,比照该时期年内的实际气候状况,着重分析年度内气候异常与葡萄产量下降、品质降低之间的关系,并就如何减缓气候对葡萄生产的不利影响进行初步探讨。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号