全文获取类型
收费全文 | 756篇 |
免费 | 64篇 |
国内免费 | 12篇 |
专业分类
测绘学 | 36篇 |
大气科学 | 63篇 |
地球物理 | 194篇 |
地质学 | 287篇 |
海洋学 | 73篇 |
天文学 | 80篇 |
综合类 | 2篇 |
自然地理 | 97篇 |
出版年
2021年 | 21篇 |
2020年 | 18篇 |
2019年 | 22篇 |
2018年 | 31篇 |
2017年 | 28篇 |
2016年 | 35篇 |
2015年 | 29篇 |
2014年 | 41篇 |
2013年 | 73篇 |
2012年 | 41篇 |
2011年 | 31篇 |
2010年 | 29篇 |
2009年 | 40篇 |
2008年 | 33篇 |
2007年 | 37篇 |
2006年 | 28篇 |
2005年 | 26篇 |
2004年 | 24篇 |
2003年 | 19篇 |
2002年 | 19篇 |
2001年 | 16篇 |
2000年 | 15篇 |
1999年 | 17篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 10篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 12篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1987年 | 2篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 8篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1967年 | 2篇 |
1966年 | 3篇 |
排序方式: 共有832条查询结果,搜索用时 281 毫秒
91.
92.
Kapil Chauhan Nicholas Hutchins Jason Monty Ivan Marusic 《Boundary-Layer Meteorology》2013,147(1):41-50
Two-point correlations of the fluctuating streamwise velocity are examined in the atmospheric surface layer over the salt flats of Utah’s western desert, and corresponding structure inclination angles are obtained for neutral, stable and unstable conditions. The neutral surface-layer results supplement evidence for the invariance of the inclination angle given in Marusic and Heuer (Phys Rev Lett 99:114504, 2007). In an extension of those results it is found that the inclination angle changes drastically under different stability conditions in the surface layer, varying systematically with the Monin–Obukhov stability parameter in the unstable regime. The variation is parametrized and subsequently can be used to improve existing near-wall models in the large-eddy simulation of the atmospheric surface layer. 相似文献
93.
Wylie A. Carr Christopher J. Preston Laurie Yung Bronislaw Szerszynski David W. Keith Ashley M. Mercer 《Climatic change》2013,121(3):567-577
There have been a number of calls for public engagement in geoengineering in recent years. However, there has been limited discussion of why the public should have a say or what the public can be expected to contribute to geoengineering discussions. We explore how public engagement can contribute to the research, development, and governance of one branch of geoengineering, solar radiation management (SRM), in three key ways: 1. by fulfilling ethical requirements for the inclusion of affected parties in democratic decision making processes; 2. by contributing to improved dialogue and trust between scientists and the public; and 3. by ensuring that decisions about SRM research and possible deployment are informed by a broad set of societal interests, values, and framings. Finally, we argue that, despite the nascent state of many SRM technologies, the time is right for the public to participate in engagement processes. 相似文献
94.
Flooding on the German Rhine during the 20th century was tested for trends and assessed to identify causal mechanisms driving worsening of flooding. A review of previous research outlines the range of impacts due to climate change, land‐use shifts, and river regulation. Analysis of hydrologic data, especially of the long record at Cologne, documents statistically significant increases in both flood magnitudes and frequencies. Specific‐gauge analysis, which isolates the effects of channel modification, documents that 20th century river engineering has caused little of the observed increase in flooding on the German Rhine. Precipitation records from the Rhine basin confirm that flood magnification has been driven by upstream factors, including an increase in flood‐producing precipitation of roughly 25% during the past 100 years and increases in runoff yields. In addition, agricultural land‐use records suggest that flood magnification can be partially explained by 20th century trends documenting intensification and industrialization of German agriculture. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
95.
William S. Burgett Michael M. Vick David S. Davis Matthew Colless Roberto De Propris Ivan Baldry Carlton Baugh Joss Bland-Hawthorn Terry Bridges Russell Cannon Shaun Cole Chris Collins Warrick Couch Nicholas Cross Gavin Dalton Simon Driver George Efstathiou Richard Ellis Carlos S. Frenk Karl Glazebrook Edward Hawkins Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick Peder Norberg John A. Peacock Will Percival Bruce Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2004,352(2):605-654
96.
97.
Nicholas J. Cox 《The Professional geographer》1980,32(1):51-54
Hitch-hiking has been ignored by traditional geography. In this article it is shown that ideas and techniques from the new geography yield substantial insights into its character as a spatial process. 相似文献
98.
99.
100.
Sediment (surface and core) sampling was conducted during the period from August 96-December 98 from intertidal and offshore areas in Kuwait Bay. The highest (and most variable) concentrations of total mercury (T-Hg; 36500+/-34930 ng g(-1)) are encountered around the previous industrial outfall where sediments are disturbed by shipping activities. The concentrations of T-Hg are lower in the Shuwaikh Port area (650+/-210 ng g(-1)) and continue to decrease towards the northern coastline of Kuwait Bay (average concentrations in the wider Bay region are 50+/-30 ng g(-1)). These values are still above background concentrations of 15-20 ng g(-1). Calculation of the total inventory of mercury in all the surface sediments of the studied area indicates that approximately 22.5 ton is present which is similar to the estimated industrial discharges of approximately 20 ton suggesting that the contamination is largely confined to the Bay and that releases to the wider Gulf region are small. The distributions of MeHg are similar to those of T-Hg and represent ranges between 0.23% and 0.5% of the T-Hg indicating that surface sediments within Kuwait Bay contain approximately 80 kg of this chemical. 相似文献