全文获取类型
收费全文 | 138篇 |
免费 | 13篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 1篇 |
2017年 | 5篇 |
2016年 | 10篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 52篇 |
2012年 | 7篇 |
2011年 | 3篇 |
2010年 | 5篇 |
2009年 | 7篇 |
2008年 | 4篇 |
2007年 | 2篇 |
2006年 | 5篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有151条查询结果,搜索用时 15 毫秒
31.
M. Lucía Balarino 《Alcheringa: An Australasian Journal of Paleontology》2013,37(3):317-337
The first palynozonation for Permian strata of the Claromecó Basin (Argentina) is formally proposed, based on palynological assemblages recovered from the UTAL.CMM1 La Estrella.x-1 and UTAL.CMM1 Cruz de Sur.x-1 boreholes, drilled on the Argentinian Continental Platform and correlation with established zones from neighbouring basins. Fifty-five samples were analyzed and 131 species identified from two biozones. The lower Converrucosisporites confluens–Vittatina vittifera (CV) Zone occurs in the Piedra Azul and Bonete formations of both boreholes. This zone can be assigned a Cisuralian–Guadalupian age. The upper Tornopollenites toreutos–Reduviasporonites chalastus (TC) Zone registered in the Tunas Formation can be assigned a Guadalupian–Lopingian age. The CV Zone is dominated by diverse non-taeniate bisaccate, plicate and taeniate pollen. Monosaccate and monosulcate pollen, algae and acritarchs are poorly represented in both biozones. The composition of the TC Zone is broadly similar to the CV Zone, but bisaccate pollen grains are markedly more diverse and abundant in the former. 相似文献
32.
Amit K. Ghosh Ratan Kar Reshmi Chatterjee 《Alcheringa: An Australasian Journal of Paleontology》2013,37(1):92-98
Disc-like galls are reported on the Triassic corystosperm leaf Dicroidium hughesii (Feistmantel) Lele from the Parsora Formation of South Rewa Gondwana Basin, central India. Although there have been numerous reports of arthropod–plant interactions from Permian and Lower Cretaceous successions, this is the first unequivocal report of arthropod–plant interactions from the Triassic succession of Peninsular India. The new record adds to global evidence that arthropod herbivory and gall formation, in particular, had rediversified by the Late Triassic in the wake of the end-Permian mass extinction. 相似文献
33.
R.E. Wass 《Alcheringa: An Australasian Journal of Paleontology》2013,37(1):41-48
Examples of early astogeny in the species Carinatocella harmeri (Stach), Costaticella hastata (Busk) and Claviporella aurita (Busk) are discussed. The primary zoid differs in each species and if found fossil, only in C. hastata could this zoid be recognised as a bryozoan fragment. Analogous development in other Bryozoa is discussed. 相似文献
34.
Geoffrey Playford Francine Martin 《Alcheringa: An Australasian Journal of Paleontology》2013,37(3):187-223
A left mandibular toothplate of a chimaeroid fish collected from the Toolebuc Formation (Early Cretaceous, Albian), central Queensland is described. Comparisons with other chimaeroid genera show the toothplate to be sufficiently distinct to warrant the erection of a new genus. Ptyktoptychion tayyo gen. et sp. nov. is distinguished by the size and shape of its three tritors, the form of the symphysial facet and the overall shape of the toothplate. 相似文献
35.
黑河流域居民生活质量研究 总被引:1,自引:0,他引:1
以《Calvert-Henderson生活质量指标》一书为理论指导构建了生活质量评价指标体系,通过开展生活质量问卷调查及查找相关统计资料,运用主成分分析法确定指标的权重,研究了我国西北地区第二大内陆河流域-黑河流域城乡居民2004年的生活质量。具体的评价结果是:黑河流域城镇居民生活质量明显高于农村;黑河流域城市居民生活质量表现出中游高于上游和下游;黑河流域农村居民生活质量以乡镇为单位计算差异显著;黑河流域农村居民生活质量中游略好于上游、下游;影响黑河流域城乡居民生活质量的主要因素是收入、教育和住房。 相似文献
36.
Kaye L. Cotter 《Alcheringa: An Australasian Journal of Paleontology》2013,37(2):63-86
The discovery of a rich assemblage of microfossils from the Neoproterozoic western Officer Basin (Centralian Superbasin) provides a more complete understanding of the biostratigraphy of this Basin. The microfossils are found in Supersequence 1 (~800 Ma) in Western Australia. The assemblages are comprised of acritarchs and cyanobacteria isolated by acid maceration from siliciclastics of the Browne (Madley), Hussar, Kanpa and Steptoe Formations. The distinctive acritarchs Cerebrosphaera buickii, Satka colonialica, Stictosphaeridium sinapticuliferum and Pterospermopsimorpha insolita are of particular interest in the Neoproterozoic. These taxa are found in similar depositional environments in Spitsbergen, Arizona, Canada and Siberia. This evidence, together with lithostratographic correlations, isotope chemostratigraphy, and sequence analysis contributes to the continuing development of Neoproterozoic stratigraphy. 相似文献
37.
Terrestrial reptile remains are very rare in the Lower Cretaceous of South Australia, but include the holotype of the small theropod Kakuru. Here, we review this taxon and other archosaur specimens collected from the Bulldog Shale (Aptian) of Andamooka and Coober Pedy. Kakuru possesses no unique characters or character state combinations and is regarded as a nomen dubium, representing an indeterminate tetanuran theropod. Two other specimens (a left metatarsal and astragalus) can be referred to Dinosauria, but the identity of several other specimens (phalanges and a centrum) can only be resolved to the level of an indeterminate archosaur. 相似文献
38.
复合生态系统下城市高质量发展时空演化及驱动因素研究——以黄河流域7大城市群为例 总被引:1,自引:0,他引:1
基于复合生态系统理论,构建高质量发展评价体系,考察了2010—2018年黄河流域城市群高质量发展时空演化特征与驱动因素,结果表明:①城市群高质量发展呈“下游领先、中游振兴、上游落后”的空间特征,经济发展水平与社会民生低下是首要制约因素。②高质量发展水平趋于收敛,但区域差异显著,资源环境促进高质量发展趋同。③高质量发展耦合逐年攀升,协调度下降趋势明显,东西非均衡化特征突出。④高质量发展的空间差异性由多因子共同作用,其中科技创新是核心驱动因子。 相似文献
39.
40.