全文获取类型
收费全文 | 183篇 |
免费 | 2篇 |
国内免费 | 3篇 |
专业分类
测绘学 | 19篇 |
大气科学 | 13篇 |
地球物理 | 41篇 |
地质学 | 55篇 |
海洋学 | 24篇 |
天文学 | 24篇 |
自然地理 | 12篇 |
出版年
2024年 | 1篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 13篇 |
2012年 | 11篇 |
2011年 | 8篇 |
2010年 | 4篇 |
2009年 | 11篇 |
2008年 | 10篇 |
2007年 | 9篇 |
2006年 | 10篇 |
2005年 | 12篇 |
2004年 | 4篇 |
2003年 | 9篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有188条查询结果,搜索用时 15 毫秒
111.
Clive D. Roberts 《新西兰海洋与淡水研究杂志》2013,47(1):157-161
Seventeen demersal fish species collected during a commercial line fishing trip off northern New Zealand are listed together with data on abundance, location, and habitat. These are the first records for the area; 15 are the most northerly records for the species and major range extensions are recorded for Centroscymnus owstoni, Deania calcea, Etmopterus lucifer, Pseudophycis barbata, and Hyperoglyphe antarctica. A prespawning aggregation of ling, Genypterus blacodes, is recorded for the first time from this region. 相似文献
112.
Devonian faunas including conodonts, radiolari-ans, tentaculitids and other important fossils have re-cently been found at several localities in the Indochina Terrane. These faunas are biostratigraphically and tectonically important. 相似文献
113.
Clive Barnett 《Geoforum》2012,43(4):677-686
Post-Marxist and poststructuralist ontologies of the political have been important reference points for recent discussions of democracy in critical human geography and related fields. This paper considers the conceptual placement of contestation in a strand of democratic theory often denigrated by these approaches, namely theories of deliberative democracy informed by post-Habermasian Critical Theory. It is argued that this concern with contestation derives from a focus on the relationships between different rationalities of action. It is proposed that this tradition of thought informs a distinctively phenomenological approach to understanding the situations out of which democratic energies emerge. In elaborating on this phenomenological understanding of the emergence of political space, the paper proceeds in three stages. First, it is argued that the strong affinities between ontological conceptualisations of ‘the political’ and the ontological register of canonical spatial theory squeezes out any serious consideration of the plural rationalities of ordinary political action. Second, debates between deliberative and agonistic theorists of democracy are relocated away from questions of ontology. These are centred instead on disputed understandings of ‘normativity’. This move opens up conceptual space for the analysis of phenomenologies of injustice. Third, using the example of debates about transnational democracy in which critical theorists of deliberative democracy explicitly address the reconfigurations of the space of ‘the political’, it is argued that this Critical Theory tradition can contribute to a distinctively ‘topological’ sense of political space which follows from thinking of political action as emerging from worldly situations of injustice. In bringing into focus this phenomenological approach to political action, the paper has lessons for both geographers and political theorists. Rather than continuing to resort to a priori models of what is properly political or authentically democratic, geographers would do well to acknowledge the ordinary dynamics and disappointments which shape political action. On the other hand, political theorists might do well to acknowledge the limits of the ‘methodological globalism’ that characterises so much recent work on the re-scaling of democracy. 相似文献
114.
115.
Berhe Goitom Clive Oppenheimer James O. S. Hammond Raphaël Grandin Talfan Barnie Amy Donovan Ghebrebrhan Ogubazghi Ermias Yohannes Goitom Kibrom J- Michael Kendall Simon A. Carn David Fee Christine Sealing Derek Keir Atalay Ayele Jon Blundy Joanna Hamlyn Tim Wright Seife Berhe 《Bulletin of Volcanology》2015,77(10):1-21
116.
117.
The petrogenesis of Apollo 14 high-Al basaltic melts was studied using crystal stratigraphy, which involves textural (crystal size distributions — CSDs) and chemical analyses (electron microprobe and laser ablation inductively coupled plasma mass spectrometry). The samples studied here include pristine basalt 14072 and basaltic clasts from breccia 14321, and impact-generated crystalline samples 14073, 14276 and 14310. Plagioclase was the focus of this study because of its relatively high modal abundances and because it was on the liquidus for much of the melt cooling histories. Plagioclase crystals were analyzed (core-to-rim compositions where possible) to test and refine petrogenetic models based upon whole-rock compositions (Groups A, B, and C designations) and to investigate basalt 14072 and impact-melt crystallization. Textural studies have shown that each basalt group has distinctive plagioclase CSDs, which are in turn distinctive from those of the impact melts. Evolution of the individual basaltic melts was studied by comparing the equilibrium-melt compositions (calculated from plagioclase compositions using relevant partition coefficients) to fractional crystallization (FC) and assimilation and fractional crystallization (AFC) models. Petrogenetic modeling of trace elements in Group A basalts revealed that petrogenesis continued beyond 40% total crystallization required to model whole-rock compositions, and that there were open-system processes that affected the magma during plagioclase crystallization. Petrogenetic modeling of pristine high-Al basalts (14072 and Groups A, B and C) using trace elements shows that the equilibrium-melt compositions do not fall on a single AFC or FC trajectory. This is consistent with fluctuating degrees of assimilation (i.e., variable r-values) and/or variable assimilant compositions during petrogenesis. Petrogenetic modeling reveals that the impact melts experienced only closed-system fractional crystallization. This work demonstrates the importance of crystal stratigraphy in revealing the intricacies of lunar basalt petrogenesis. 相似文献
118.
Michael Batty Robin Morphet Paolo Masucci Kiril Stanilov 《Journal of Geographical Systems》2014,16(4):363-385
We pose the central problem of defining a measure of complexity, specifically for spatial systems in general, city systems in particular. The measures we adopt are based on Shannon’s (in Bell Syst Tech J 27:379–423, 623–656, 1948) definition of information. We introduce this measure and argue that increasing information is equivalent to increasing complexity, and we show that for spatial distributions, this involves a trade-off between the density of the distribution and the number of events that characterize it; as cities get bigger and are characterized by more events—more places or locations, information increases, all other things being equal. But sometimes the distribution changes at a faster rate than the number of events and thus information can decrease even if a city grows. We develop these ideas using various information measures. We first demonstrate their applicability to various distributions of population in London over the last 100 years, then to a wider region of London which is divided into bands of zones at increasing distances from the core, and finally to the evolution of the street system that characterizes the built-up area of London from 1786 to the present day. We conclude by arguing that we need to relate these measures to other measures of complexity, to choose a wider array of examples, and to extend the analysis to two-dimensional spatial systems. 相似文献
119.
Kayla Iacovino Gordon Moore Kurt Roggensack Clive Oppenheimer Philip Kyle 《Contributions to Mineralogy and Petrology》2013,166(3):845-860
We present new equilibrium mixed-volatile (H2O–CO2) solubility data for a phonotephrite from Erebus volcano, Antarctica. H2O–CO2-saturated experiments were conducted at 400–700 MPa, 1,190 °C, and ~NNO + 1 in non-end-loaded piston cylinders. Equilibrium H2O–CO2 fluid compositions were determined using low-temperature vacuum manometry, and the volatile and major element compositions of the glassy run products were determined by Fourier transform infrared spectroscopy and electron microprobe. Results show that the phonotephrite used in this study will dissolve ~0.8 wt% CO2 at 700 MPa and a fluid composition of $ X_{{{\text{H}}_{ 2} {\text{O}}}} $ ~0.4, in agreement with previous experimental studies on mafic alkaline rocks. Furthermore, the dissolution of CO2 at moderate to high $ X_{{{\text{H}}_{ 2} {\text{O}}}}^{\text{fluid}} $ in our experiments exceeds that predicted using lower-pressure experiments on similar melts from the literature, suggesting a departure from Henrian behavior of volatiles in the melt at pressures above 400 MPa. With these data, we place new constraints on the modeling of Erebus melt inclusion and gas emission data and thus the interpretation of its magma plumbing system and the contributions of primitive magmas to passive and explosive degassing from the Erebus phonolite lava lake. 相似文献
120.