全文获取类型
收费全文 | 76篇 |
免费 | 5篇 |
国内免费 | 29篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 20篇 |
地球物理 | 7篇 |
地质学 | 27篇 |
海洋学 | 42篇 |
综合类 | 12篇 |
自然地理 | 1篇 |
出版年
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 6篇 |
2013年 | 4篇 |
2012年 | 5篇 |
2011年 | 6篇 |
2010年 | 4篇 |
2009年 | 2篇 |
2008年 | 17篇 |
2007年 | 5篇 |
2006年 | 6篇 |
2005年 | 8篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有110条查询结果,搜索用时 15 毫秒
71.
贡嘎山海螺沟冰川冰舌地段的泥石流 总被引:4,自引:0,他引:4
海螺沟冰川冰舌地段1976年以来发生过两次大的冰雪雨水泥石流。1989年7月8日和26日观景台西沟的泥石流通过1.7km长的冰面后,在冰川末端前形成一个5.5×10~4m~3的扇形地;1976年8月长草坝3号冰川下部冰碛体边坡的两处滑坡泥石流在开阔地上扩散堆积后,达1317.8m~3/s的泥石流和洪水下到冰川上。今后每年雨季还有可能发生更大规模的泥石流,值得人们警惕。 相似文献
72.
Counterclockwise P-T-t trajectory from the metamorphic sole of a Neo-Tethyan ophiolite (Turkey) 总被引:2,自引:0,他引:2
The Kiziltepe ophiolitic thrust sheet in the Bolkar Mountains of Turkey occurs between two subparallel ophiolite belts bounding the Tauride carbonate platform and represents a remnant of the Cretaceous Neo-Tethyan oceanic lithosphere. It is underlain by foliated amphibolite that represents a metamorphic sole developed at the inception of an intra-oceanic subduction zone in the Neo-Tethys 92-90 Ma. Blueschist-facies overprinting of the amphibolite indicates that the metamorphic sole was dragged deeper into the subduction zone where it experienced increasing P/T with cooling. Regional tectonic constraints suggest a Maastrichtian age for the timing of this blueschist-facies metamorphism. Sodic amphibole-rich veins and crossite/Mg-riebeckite rims on hornblende suggest that growth of blueschist-facies minerals was facilitated by infiltration of fluid along fractures and grain boundaries. We infer a counterclockwise P-T-t trajectory during which metamorphism was accompanied/succeeded by rapid uplift along the northern edge of the Tauride belt in Late Cretaceous-early Tertiary time. 相似文献
73.
M. Ishtiaq 《GeoJournal》1998,45(3):189-200
Language shift from traditional language to non-traditional has become an important aspect of the study in various disciplines
including social and regional sciences besides linguistics. The geographers have studied the patterns of spatial distribution
and the processes through which the shift occurs and also analysed the factors which are responsible for the shift. Socio-economic
and political implications of the shift have been adequately emphasized in geographical studies. The present study is an attempt
in this direction by selecting some of the important tribal groups of Central India.
The paper attempts to establish the relationship between language shift and socio-economic conditions among the Bhils, the
Korkus, the Mundas and the Santals of Central India. The stepwise regression model has been applied to understand the causality
of the shift while the degree of linguistic exposure has been calculated to determine the magnitude of language shift among
them for a comparative analysis. Both primary and secondary data have been analysed for this study.
Though language shift among the tribal population has exposed them to the outside world and helped them to achieve higher
levels of socio-economic development, its consequences seem to be more serious as it has led to the division of the tribal
society and formation of separate groups of people who have been alienated from the traditional people. Thus, the process
of linguistic shift is held responsible for the loss of tribal identity and their traditional culture.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
74.
Spawning grounds of the soles, Solea solea and Solea senegalensis, are distant from the estuarine nurseries where juveniles concentrate. Recruitment of these species is highly dependent on the success of the larval migration towards the inshore nursery grounds. Unfavourable climate and hydrodynamic circulation may lead to high mortality rates at this stage. The relation between river drainage, NAO index and the North-South wind component intensity over the three months prior to the end of the estuarine colonization and the densities of S. solea and S. senegalensis in the nursery grounds were investigated for both species based on a discontinuous historical dataset (from 1988 to 2006) for the Tagus estuary. Multiple linear regression models were developed for sole density and environmental data (separately for each species). Results showed that river drainage is positively correlated with juveniles’ densities of both species, possibly due to the existence of chemical cues used by larvae for movement orientation. NAO index and the North-South wind component intensity relations with soles densities were non-significant. It was concluded that the high complexity of the Portuguese upwelling system makes it hard to detect causal relations of the environmental variables tested. The importance of river flow for coastal ecosystems was stressed. Since climate change scenarios predict a strong decrease in rain fall over the Portuguese river basins, as well as a concentrated period of heavy rain in winter, it was hypothesised that future river drainage decrease over much of the year may lead to lower recruitment success for soles, especially for S. senegalensis. 相似文献
75.
76.
77.
2012年5月21—22日,贵州省出现了一次典型的Ⅲ型静止锋在南支槽的引导下锋生而触发MCS形成暴雨的过程。MCS有非线性、降水强的特征。分析发现:低层静止锋锋区强,锋生明显;锋前有高能舌及低涡切变发展,切变南侧有偏南急流。垂直方向上锋区陡峭,锋前上凸区内上升气流强,对流不稳定;南支槽及高低空系统的前倾配置是上升气流强的原因。这些锋面特征为MCS发生发展提供了有利条件:低层高能舌和低涡切变为MCS提供了热力和动力条件;偏南急流是影响MCS的重要因素。锋前上凸区是MCS发展的重要区域,锋区附近的θse场及高低空系统前倾配置利于MCS发生发展。锋前到锋区附近的水汽条件好,急流出口处的水汽辐合及上升气流为MCS和大暴雨提供了有利水汽输送。 相似文献
78.
A complementary DNA (cDNA) library was constructed from half-smooth tongue sole spleen. A long-read expressed sequence tag
(EST) database was generated, containing 3100 cDNA clones, of which 220 clones were fully sequenced. A total of 1060 non-redundant
simple sequence repeats (SSRs) were obtained from the cDNA library. An average of 5 kb sequence generates 1 SSR in the half-smooth
tongue sole spleen cDNA library. The proportion of the SSR unit size was different in the cDNA library. The monomeric repeats
(51.4%) are the most abundant class of SSR in the dataset. The dimeric, trimeric, tetrameric and hexameric repeats are represented
in decreasing proportions of 27.2%, 16.0%, 2.8% and 1.9%, respectively. The frequency of pentameric repeats was observed the
least (only 0.7%). Most of the monomeric and dimeric repeats are distributed in 3′ and 5′ un-translation region. If translation
regions are considered merely, trimeric repeats are the highest, accounting for 57% of the total microsatellites. 相似文献
79.
Lasafam Iturrizaga 《山地科学学报》2008,5(1)
The Kvíárj(o)kull.a southern outlet glacier of the Vatnaj(o)kull,is confined in the mountain foreland by lateral moraines measuring a height of up to 150 m.Each of the lateral moraines shows consjderable breaches with deviations of the main moraine ridges.The paper discusses the possible origins of these modifications of the lateral moraines as result of:1)ice overlappings during glacier advances and subsequent breaches of the lateraltongue triggered by the preglacial relief conditions and the prehistorical moraine landscape leading to affiux conditions,3)drainage of ice-marginal glacier lakes and 4.volcanic activities,such as lava flows and volcanic-induced j(o)kulhlaups. A historic-genetic model of the formation of the lateral moraines is presented considering the breaches in the lateral moraines as result from glacier bifurcations and therefore as former tributary tongue basins.Such breaches in the lateral moraines are also common landscape features at glaciers outside of Iceland and are from wider importance for the paleoreconstruction of former glacier stages.The knowledge of their development is essential for an adequate relative age classification of individual moraine ridges.In regard to the origin of the debris the resedimentation of prehistoric till deposits by younger glacier advances plays a role in the formation of the lateral moraines apart from englacial and supraglacial sediment transfer processes. 相似文献