全文获取类型
收费全文 | 1576篇 |
免费 | 135篇 |
国内免费 | 10篇 |
专业分类
测绘学 | 46篇 |
大气科学 | 160篇 |
地球物理 | 535篇 |
地质学 | 563篇 |
海洋学 | 107篇 |
天文学 | 227篇 |
综合类 | 7篇 |
自然地理 | 76篇 |
出版年
2023年 | 5篇 |
2022年 | 13篇 |
2021年 | 38篇 |
2020年 | 42篇 |
2019年 | 31篇 |
2018年 | 37篇 |
2017年 | 58篇 |
2016年 | 101篇 |
2015年 | 93篇 |
2014年 | 113篇 |
2013年 | 174篇 |
2012年 | 137篇 |
2011年 | 83篇 |
2010年 | 88篇 |
2009年 | 75篇 |
2008年 | 53篇 |
2007年 | 28篇 |
2006年 | 69篇 |
2005年 | 39篇 |
2004年 | 29篇 |
2003年 | 30篇 |
2002年 | 44篇 |
2001年 | 26篇 |
2000年 | 12篇 |
1999年 | 15篇 |
1998年 | 17篇 |
1997年 | 18篇 |
1996年 | 9篇 |
1995年 | 19篇 |
1994年 | 11篇 |
1993年 | 9篇 |
1992年 | 7篇 |
1991年 | 19篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 13篇 |
1983年 | 12篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 13篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1974年 | 7篇 |
1973年 | 10篇 |
1969年 | 7篇 |
排序方式: 共有1721条查询结果,搜索用时 15 毫秒
71.
Catherine Robin Shannon Nudds Phillip MacAulay André Godin Bodo De Lange Boom Jason Bartlett 《Marine Geodesy》2016,39(2):195-222
Since the advent of Global Navigation Satellite Systems, it has been possible to perform hydrographic survey reductions through the ellipsoid, which has the potential to simplify operations and improve bathymetric products. This technique requires a spatially continuous separation surface connecting chart datum (CD) to a geodetic ellipsoid. The Canadian Hydrographic Service (CHS), with support from the Canadian Geodetic Survey, has developed a new suite of such surfaces, termed Hydrographic Vertical Separations Surfaces, or HyVSEPs, for CD and seven tidal levels. They capture the spatial variability of the tidal datum and levels between tide gauges and offshore using semiempirical models coupling observations at tide stations with relative sea-level rise estimates, dynamic ocean model solutions, satellite altimetry, and a geoid model. HyVSEPs are available for all tidal waters of Canada, covering over seven million square kilometers of ocean and more than 200,000 kilometers of shoreline. This document provides an overview of the CHS's modeling approach, tools, methods, and procedures.
The HyVSEP for CD defines the new hydrographic datum for the tidal waters of Canada. HyVSEPs for other tidal levels are fundamental for coastal studies, climate change adaptation and the definition of the Canadian shoreline and offshore boundaries. HyVSEPs for inland waters are not discussed. 相似文献
72.
Crustacean decapod assemblages associated with fragmented Posidonia oceanica meadows in the Alboran Sea (Western Mediterranean Sea): composition,temporal dynamics and influence of meadow structure 下载免费PDF全文
Ángel Mateo‐Ramírez Javier Urra Pablo Marina José L. Rueda José Enrique García Raso 《Marine Ecology》2016,37(2):344-358
The decapod assemblage associated with a Posidonia oceanica meadow located near its western limit of biogeographic distribution was studied over an annual cycle. Fauna samples were taken seasonally over a year (five replicates per season) in two sites located 7 km apart, using a non‐destructive sampling method (airlift sampler) for the seagrass. The dominant species of the assemblage, Pisidia longimana, Pilumnus hirtellus and Athanas nitescens, were associated with the protective rhizome stratum, which is mainly used as a nursery. The correlations between decapod assemblage structure and some phenological parameters of the seagrass shoots and wave height were negative or null, which reflects that species associated with the rhizome had a higher importance than those associated with the leaf stratum. The abundance and composition of the decapod assemblage as well as the ecological indexes displayed a seasonality trend with maximum values in summer‐autumn and minimum in winter‐spring, which were related to the seawater temperature and the recruitment periods of the dominant species. The spatial differences found in the structure and dynamics of the assemblages may be due to variations in the recruitment of the dominant species, probably as a result of the influence of local factors (e.g. temperature, currents) and the high dispersal ability of decapods, together with the patchy configuration and the surrounding habitats. The studied meadows are fragmented and are integrated within a mosaic of habitats (Cymodocea nodosa patches, algal meadows, rocky and sandy bottoms), which promotes the movement of individuals and species among them, maintaining a high species richness and evenness. 相似文献
73.
74.
75.
76.
77.
78.
Terrinha Pedro Pueyo Emilio L. Aranguren Aitor Kullberg José Carlos Kullberg Maria Carla Casas-Sainz Antonio Azevedo Maria do Rosário 《International Journal of Earth Sciences》2018,107(5):1807-1833
International Journal of Earth Sciences - The geometry and emplacement of the ~ 96 km2, Late Cretaceous Sintra Igneous complex (SIC, ca. 80 Ma) into the West Iberian passive... 相似文献
79.
Grajales-Nishimura José Manuel Ramos-Arias Mario Alfredo Solari Luigi Murillo-Muñetón Gustavo Centeno-García Elena Schaaf Peter Torres-Vargas Ricardo 《International Journal of Earth Sciences》2018,107(3):1005-1031
International Journal of Earth Sciences - The Juchatengo complex (JC) suite is located between the Proterozoic Oaxacan complex to the north and the Xolapa complex to the south, and was amalgamated... 相似文献
80.
Filho Hugo Carlos Scheuermann Martins Carlos Guilherme Menezes Ricardo José Wink Dornelles Lucas Eduardo Consoli Nilo Cesar 《Geotechnical and Geological Engineering》2021,39(7):5395-5404
Geotechnical and Geological Engineering - Dispersive soils are susceptible to phenomena of internal and external erosion when in contact with relatively pure water due to its particle’s... 相似文献