全文获取类型
| 收费全文 | 3653篇 |
| 免费 | 937篇 |
| 国内免费 | 1069篇 |
专业分类
| 测绘学 | 157篇 |
| 大气科学 | 1525篇 |
| 地球物理 | 1070篇 |
| 地质学 | 882篇 |
| 海洋学 | 897篇 |
| 天文学 | 56篇 |
| 综合类 | 295篇 |
| 自然地理 | 777篇 |
出版年
| 2024年 | 11篇 |
| 2023年 | 49篇 |
| 2022年 | 143篇 |
| 2021年 | 159篇 |
| 2020年 | 186篇 |
| 2019年 | 195篇 |
| 2018年 | 179篇 |
| 2017年 | 207篇 |
| 2016年 | 178篇 |
| 2015年 | 214篇 |
| 2014年 | 266篇 |
| 2013年 | 246篇 |
| 2012年 | 276篇 |
| 2011年 | 259篇 |
| 2010年 | 198篇 |
| 2009年 | 241篇 |
| 2008年 | 219篇 |
| 2007年 | 273篇 |
| 2006年 | 297篇 |
| 2005年 | 263篇 |
| 2004年 | 222篇 |
| 2003年 | 191篇 |
| 2002年 | 141篇 |
| 2001年 | 133篇 |
| 2000年 | 123篇 |
| 1999年 | 109篇 |
| 1998年 | 124篇 |
| 1997年 | 92篇 |
| 1996年 | 77篇 |
| 1995年 | 66篇 |
| 1994年 | 65篇 |
| 1993年 | 62篇 |
| 1992年 | 51篇 |
| 1991年 | 41篇 |
| 1990年 | 21篇 |
| 1989年 | 14篇 |
| 1988年 | 20篇 |
| 1987年 | 14篇 |
| 1986年 | 9篇 |
| 1985年 | 3篇 |
| 1984年 | 3篇 |
| 1983年 | 2篇 |
| 1982年 | 3篇 |
| 1981年 | 1篇 |
| 1980年 | 2篇 |
| 1979年 | 3篇 |
| 1978年 | 3篇 |
| 1977年 | 1篇 |
| 1976年 | 1篇 |
| 1954年 | 3篇 |
排序方式： 共有5659条查询结果，搜索用时 15 毫秒
91.
92.
Marco A. Lardies José Luis Muñoz Kurt A. Paschke Francisco Bozinovic 《Marine Ecology》2011,32(1):42-51
The colonisation of the terrestrial environment by crustaceans is more apparent in tropical latitudes because of the high diversity of semi‐terrestrial and terrestrial crabs. However, in temperate regions there are also great numbers of crustaceans that inhabit ecological niches at the water–air interface. Grapsidae crabs (Decopoda) are especially important in studies of water‐to‐land transition as the family contains species occupying the intertidal and adjacent regions. A way to evaluate the ability of intertidal invertebrates to breathe air is to measure the aerial/aquatic oxygen consumption ratio. The objective of this study was to test the effect of thermal variation on the aquatic and aerial metabolism. We selected as study model the decopoda crab Cyclograpsus cinereus Dana and utilised five populations of the species spread over 2000 km along the Chilean coast. To determine the compensation capacity in respiration with respect to latitude, we evaluated metabolic rate at the same temperature in a common garden design in the laboratory, to examine the extent to which variation in crab physiology is environmentally determined. Whereas in our study, mb (body mass) varied significantly with latitude, the difference in mass‐independent metabolism both in air and water persisted, indicating that observed differences in MR (Metabolic Rate) were not an effect of differences in body size. We demonstrated that C. cinereus is able to breath oxygen from air and water as expected for an amphibious crab. Almost all the studied populations of C. cinereus show a aerial/aquatic metabolism ratio near 1. The pattern found indicates an increase in metabolic rate, both aerial and aquatic, in low latitudes and therefore does not support the latitudinal compensation hypothesis for temperate habitats. Finally, these kinds of studies are required to make the necessary link between ecological physiology and macroecology and to help develop a global understanding of organismal function in marine systems. 相似文献
93.
94.
95.
A singular value decomposition (SVD) analysis is carried out to reveal the relationship between the interannual variation of track and intensity of the western North Pacific tropical cyclones (WNPTCs) in the tropical cyclone (TC) active season (July-November) and the global net air-sea heat flux (Q net ) in the preceding season (April-June). For this purpose, a tropical cyclone track and intensity function (TIF) is defined by a combination of accumulated cyclone energy (ACE) index and a cyclone track densit... 相似文献
96.
Low-frequency variability of the North Equatorial Current bifurcation in the past 40 years from SODA 总被引：1，自引：1，他引：0
The low-frequency variability of the North Equatorial Current (NEC) bifurcation during 1958 to 2001 was investigated with the Simple Ocean Data Assimilation (SODA) 2.0.2 dataset.In agreement with recent observations,the NEC bifurcation latitude (NBL) shifted northward as depth increases, from about 12.7°N near the surface to about 17.1°N at depths around 500 m for the annual average. This study reveals that the interannual variations of NBL,with five years period,mainly focused on the upper 500 m with amplitude increasing as depth increased.The NBL shifted southward in the past 40 years,which was more significant in the subsurface at more than -0.02°/a.The NBL manifests itself in the transports of NMK (NEC-Mindanao Current (MC)-Kuroshio) system in strong relationship with MC (0.7) and Kuroshio (-0.7).The EOF analysis of meridional velocity off the Philippine coast shows that the first mode,explaining 62% of variance and 5 years period,was highly correlated with the southward shift of NBL with coefficient at about 0.75.The southward shift of NBL consists with the weakening of MC and strengthening of Kuroshio,which exhibited linear trends at -0.24Sv/a and 0.11Sv/a.Both interannual variation and trend of NBL were closely related to the variation of NMK system. 相似文献
97.
用沿岸上升流指数分析中国东南沿岸风生上升流的特征 总被引：2，自引：0，他引：2
对1968年1月到2007年12月中国东南沿海(17°N～30°N,109°E～123°E)上升流指数月平均数据进行分析,结论如下:(1)风生沿岸上升流主要在4-8月间发生于海南岛东部、雷州半岛东部、汕头以北至浙江沿岸.(2)风生沿岸上升流的强度具有时空分布变化特征,其中海南岛东部沿岸上升流最强,浙江沿岸其次;整个中国... 相似文献
98.
99.
100.