全文获取类型
收费全文 | 435篇 |
免费 | 45篇 |
国内免费 | 117篇 |
专业分类
测绘学 | 4篇 |
大气科学 | 13篇 |
地球物理 | 56篇 |
地质学 | 179篇 |
海洋学 | 298篇 |
天文学 | 1篇 |
综合类 | 16篇 |
自然地理 | 30篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 8篇 |
2021年 | 12篇 |
2020年 | 20篇 |
2019年 | 20篇 |
2018年 | 14篇 |
2017年 | 14篇 |
2016年 | 13篇 |
2015年 | 15篇 |
2014年 | 19篇 |
2013年 | 36篇 |
2012年 | 24篇 |
2011年 | 23篇 |
2010年 | 12篇 |
2009年 | 27篇 |
2008年 | 32篇 |
2007年 | 37篇 |
2006年 | 43篇 |
2005年 | 29篇 |
2004年 | 17篇 |
2003年 | 23篇 |
2002年 | 29篇 |
2001年 | 9篇 |
2000年 | 19篇 |
1999年 | 12篇 |
1998年 | 12篇 |
1997年 | 10篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 1篇 |
排序方式: 共有597条查询结果,搜索用时 15 毫秒
131.
132.
海表面风场可以用于获取许多大气和海洋现象的信号,高质量、高时空分辨率的海表面风场数据产品将有利于海洋-大气动力过程的研究.本文使用全球热带系泊浮标阵列计划(Global Tropical Moored Array Programs)的锚定浮标风场数据和西沙通量塔气象观测资料验证了Cyclone Global Navigation Satellite System (CYGNSS)的35°N~35°S海面遥感风场观测数据.结果表明,CYGNSS海表面风场与实测资料存在着2.17 m/s左右的平均均方根误差(RMSD),它可能源于观测数据和卫星遥感资料的观测误差,以及两者在空间和时间上未严格匹配而引起的代表性误差.另外,CYGNSS海表面风速的时间演变与实测资料非常一致,展现了CYGNSS在研究海洋-大气能量和动量交换过程方面的潜在应用价值.本文使用Madden-Julian Oscillation (MJO)和赤道东部印度洋上升流事件作为两个个例,说明了CYGNSS海表面风场资料的潜在应用价值. 相似文献
133.
134.
Tectonic Evolution of Tertiary Basins in circum-Pacific Belt of China and Their Geodynamic Setting 总被引:1,自引:0,他引:1
Li Sitian Yang Shigong Xie XinongFaculty of Earth Resources China University of Geosciences Wuhan 《中国地质大学学报(英文版)》1997,(1)
TectonicEvolutionofTertiaryBasinsinCircum┐PacificBeltofChinaandTheirGeodynamicSeting*LiSitianYangShigongXieXinongFacultyofEar... 相似文献
135.
136.
本文利用三维数值模型(ROMS-Co Si NE)分析了整个加利福尼亚流系水平流场的季节性演变过程,研究了美国加州中部海域流场垂直结构的季节性变化特征,并探讨了其动力学机制。研究发现:(1)数值模型能够较为准确的模拟流场的季节性变化,与浮标观测数据以及前人的研究结果符合良好;(2)从表层到200m,加利福尼亚潜流向高纬度扩张,近岸上升流急流则向高纬度撤退,加州南部海域的中尺度涡更显著;(3)在加州中部海域,近岸急流的最大值(约15cm/s)发生在夏季,位于近岸的表层海域;加利福尼亚潜流最大值(约4cm/s)发生于冬季,出现在离岸100km的125m处;加利福尼亚流在春季达到全年最大值(约5cm/s),流轴位于离岸(400—600km)的表层海水。加利福尼亚流系的流场具有显著的季节性变化,研究进一步表明这主要受地转关系调控。 相似文献
137.
Zooplankton biomass and distribution in the KwaZulu-Natal Bight were investigated in relation to environmental parameters during summer (January–February 2010) and winter (July–August 2010). Mean zooplankton biomass was significantly higher in winter (17.1 mg dry weight [DW] m–3) than in summer (9.5 mg DW m?3). In summer, total biomass was evenly distributed within the central bight, low off the Thukela River mouth and peaked near Durban. In winter, highest biomass was found offshore between Richards Bay and Cape St Lucia. Zooplankton biomass in each size class was significantly, negatively related to sea surface temperature and integrated nitrate, but positively related to surface chlorophyll a and dissolved oxygen. Zooplankton biomass was significantly related to bottom depth, with greatest total biomass located inshore (<50 m). Distribution across the shelf varied with zooplankton size. Seasonal differences in copepod size composition suggest that a smaller, younger community occupied the cool, chlorophyll-rich waters offshore from the St Lucia upwelling cell in winter, and a larger, older community occurred within the relatively warm and chlorophyll-poor central bight in summer. Nutrient enrichment from quasi-permanent upwelling off Durban and Richards Bay appears to have a greater influence on zooplankton biomass and distribution in the bight than the strongly seasonal nutrient input from the Thukela River. 相似文献
138.
Nearshore marine environments are influenced by an array of variables that can either be land-derived or of marine origin, and nearshore phytoplankton communities may differ in their taxonomic composition and biomass in response to such variables. The KwaZulu-Natal Bight (hereafter referred to as ‘the bight’) is an oligo-mesotrophic, nearshore oceanic environment, that is influenced by both terrestrial run-off and upwelling. A microphytoplankton survey of the bight conducted over several stations and depths and two seasons was conducted in order to ascertain species composition, abundance and biomass. Microphytoplankton abundance was generally low (a maximum of 180 000 cells l–1 was recorded) but differed considerably between sites and seasons. A total of 99 taxa of mainly Bacillariophyceae and some Dinophyceae, Prymnesiophyceae and Cyanophyceae were identified in the present study. In the central bight, higher abundance and biomass were measured in February (wet season), which may be a possible consequence of terrestrial nutrient inputs. In the northern and southern bight we measured higher abundance and biomass in August (dry season). Upwelling was not detected during the study, but an influence of terrestrial nutrient sources was detected at the coastal stations. Turbid conditions were specific to the site near the Thukela River mouth and possibly influenced abundance, biomass and species composition at this site. Historic data on microphytoplankton composition are scarce, but comparisons with surveys from the 1960s reveal that around 60% of the common diatoms recorded then also occurred in the present study. Small taxa [20–200 µm] dominated the microphytoplankton community. Community composition was fairly uniform throughout the bight in both seasons, dominated in general by Chaetoceros species, and on occasion co-dominated by Thalassionema nitzschioides and Dactyliosolen fragilissimus. 相似文献
139.
140.