全文获取类型
收费全文 | 372篇 |
免费 | 15篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 28篇 |
地球物理 | 87篇 |
地质学 | 112篇 |
海洋学 | 26篇 |
天文学 | 99篇 |
综合类 | 1篇 |
自然地理 | 32篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 16篇 |
2020年 | 8篇 |
2019年 | 8篇 |
2018年 | 14篇 |
2017年 | 12篇 |
2016年 | 14篇 |
2015年 | 13篇 |
2014年 | 13篇 |
2013年 | 14篇 |
2012年 | 12篇 |
2011年 | 24篇 |
2010年 | 15篇 |
2009年 | 25篇 |
2008年 | 18篇 |
2007年 | 20篇 |
2006年 | 15篇 |
2005年 | 12篇 |
2004年 | 13篇 |
2003年 | 13篇 |
2002年 | 14篇 |
2001年 | 11篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 9篇 |
1981年 | 2篇 |
1979年 | 3篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1973年 | 1篇 |
排序方式: 共有387条查询结果,搜索用时 15 毫秒
331.
332.
333.
Louise M. Griffiths Andrew R. Liddle 《Monthly notices of the Royal Astronomical Society》2001,324(3):769-771
We point out that the effect of reionization on the microwave anisotropy power spectrum is not necessarily negligible on the scales probed by COBE . It can lead to an upward shift of the COBE normalization by more than the 1 σ error quoted, ignoring reionization. We provide a fitting function to incorporate reionization into the normalization of the matter power spectrum. 相似文献
334.
Vincent M. Woolf C. Simon Jeffery Donald L. Pollacco 《Monthly notices of the Royal Astronomical Society》2002,332(1):34-36
We report the results of a high-time-resolution radial velocity study of the subdwarf B star and possible Type Ia supernova progenitor KPD 1930+2752. There were no significant peaks in the power spectrum of the velocity curve above our detection limit, about 4 km s−1 , at the frequencies where peaks arising from pulsation were present in the photometric data of previous researchers. We report an orbital velocity amplitude, 348.5±1 km s-1 , in agreement with that reported by previous investigators. We find an orbital period of P =0.095 093 08±0.000 000 15 d based on our data and the ephemeris of Maxted et al. 相似文献
335.
Aaron T. David Pascale A. L. Goertler Stuart H. Munsch Brittany R. Jones Charles A. Simenstad Jason D. Toft Jeffery R. Cordell Emily R. Howe Ayesha Gray Michael P. Hannam William Matsubu Erin E. Morgan 《Estuaries and Coasts》2016,39(5):1491-1504
Compared to benthic and water-column invertebrate assemblages, considerably less is known about terrestrial arthropods inhabiting estuarine wetlands despite their importance to tidal wetland biodiversity and productivity. We also need to know more about how human modification of estuaries, including efforts to restore estuarine wetlands, affects these assemblages. To address this knowledge gap, we assembled data from multiple studies on terrestrial arthropod assemblages from 87 intertidal wetland sites in 13 estuaries along the west coast of North America. Arthropods were sampled between 1998 and 2013 with fallout traps deployed in wetlands for 1 to 3 days at a time. We describe patterns in the abundance and taxonomic composition of terrestrial arthropods and evaluate the relative ability of natural and anthropogenic factors to explain variation in abundance and composition. Arthropod abundance was highly variable. Vegetation assemblage, precipitation, and temperature best explained variation in arthropod abundance, while river discharge, latitude, and developed and agricultural land cover surrounding sampling sites were less important. Arthropod abundance rapidly achieved levels of reference wetlands after the restoration of tidal influence to leveed wetlands, regardless of surrounding land cover. However, arthropod assemblage composition was affected by the amount of developed land cover as well as restoration age. These results suggest that restoration of tidal influence to leveed wetlands can rapidly restore some components of estuarine wetland ecosystems but that recovery of other components will take longer and may depend on the extent of anthropogenic modification in the surrounding landscape. 相似文献
336.
337.
Louise Rosenberg Mette M. Broholm Nina Tuxen Ida Henriette Kerrn-Jespersen Gro Lilbæk Poul L. Bjerg 《Ground Water Monitoring & Remediation》2022,42(1):29-37
The vertical transport of contaminants from source areas is employed in many risk assessment models and screening tools in order to estimate the contaminant mass discharge (CMD) into underlying aquifers. The key parameters for estimating CMD are the contaminant source area and concentration, and the vertical water flux, the latter of which depends on the vertical hydraulic conductivity and the vertical hydraulic gradient in the subsurface. This study focuses on advancing the use of the combined membrane interface probe hydraulic profiling tool (MiHPT) to investigate the vertical hydraulic gradient across a clay till overlying a sandy aquifer at a contaminated site in Denmark. Only the HPT is necessary for the estimate of vertical hydraulic gradient. The hydraulic head, clay till thickness, and resulting vertical hydraulic gradients found using the MiHPT compared well with observations from nearby nested wells. The parameter with the largest discrepancy was the thickness of the clay till. The advantage of the MiHPT is its relatively quick depth discrete access to information regarding subsurface permeability, vertical hydraulic gradients and contaminant distribution across a site. In this case study, performance of additional dissipationtests during the HPT log to acquire determination of the vertical hydraulic gradient increased the cost by 3% compared to standard HPT logs. 相似文献
338.
Fredrik Høgaas Louise Hansen Ivar Berthling Martin Klug Oddvar Longva Helle Daling Nannestad Lars Olsen Anders Romundset 《Boreas: An International Journal of Quaternary Research》2023,52(3):295-313
This study discusses the timing and maximum flood level of the Nedre Glomsjø outburst flood, Norway, based on sediment records retrieved from 15 bog and lake basins located close to the purported maximum flooded level. The sediment records in 12 of the basins consist of a distinct light-coloured silty bed that is correlated to the outburst-flood-deposited ‘Romerike Silt Bed’ identified elsewhere in the region. The silt bed is recorded in basins up to a certain elevation and is absent above this level. The new maximum flood level inferred from the basin sediment records exceeds the established landform-induced palaeostage indicators by 5–10 m. The data indicate a higher maximum flood level and larger inundation area than previously suggested and highlight the importance of acquiring a wide range of geological data when reconstructing palaeofloods. Radiocarbon dates of terrestrial macrofossils found stratigraphically above and below the Romerike Silt Bed suggest that the glacial lake Nedre Glomsjø outburst flood occurred between 10.5 and 10.3 cal. ka BP. The new and well-constrained timing of the outburst flood is beneficial for reconstructing regional deglaciation and provides a precise age for the Romerike Silt Bed chronostratigraphical marker, which is of value for studies in SE Norway and adjacent regions. 相似文献
339.
Llanes Francesca V. Eco Rodrigo Herrero Tatum Miko Briones Jo Brianne Louise Escape Carmille Marie Sulapas Jolly Joyce Galang Jan Albert Macario Ortiz Iris Jill Sabado Jasmine May Lagmay Alfredo Mahar Francisco Rodolfo Kelvin 《Natural Hazards》2022,114(1):665-690
Natural Hazards - In October 2015, heavy rains brought by Typhoon Koppu generated landslides and debris flows in the municipalities of Bongabon, Laur, and Gabaldon in Nueva Ecija province.... 相似文献
340.