全文获取类型
收费全文 | 1136篇 |
免费 | 35篇 |
国内免费 | 26篇 |
专业分类
测绘学 | 23篇 |
大气科学 | 99篇 |
地球物理 | 244篇 |
地质学 | 297篇 |
海洋学 | 235篇 |
天文学 | 197篇 |
综合类 | 11篇 |
自然地理 | 91篇 |
出版年
2022年 | 8篇 |
2021年 | 13篇 |
2020年 | 20篇 |
2019年 | 23篇 |
2018年 | 38篇 |
2017年 | 31篇 |
2016年 | 39篇 |
2015年 | 33篇 |
2014年 | 45篇 |
2013年 | 75篇 |
2012年 | 48篇 |
2011年 | 54篇 |
2010年 | 52篇 |
2009年 | 56篇 |
2008年 | 51篇 |
2007年 | 51篇 |
2006年 | 40篇 |
2005年 | 32篇 |
2004年 | 28篇 |
2003年 | 22篇 |
2002年 | 28篇 |
2001年 | 18篇 |
2000年 | 29篇 |
1999年 | 28篇 |
1998年 | 15篇 |
1997年 | 16篇 |
1996年 | 9篇 |
1995年 | 16篇 |
1994年 | 9篇 |
1993年 | 14篇 |
1992年 | 14篇 |
1991年 | 7篇 |
1989年 | 10篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1981年 | 8篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 12篇 |
1976年 | 10篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1973年 | 10篇 |
1915年 | 6篇 |
1907年 | 7篇 |
排序方式: 共有1197条查询结果,搜索用时 468 毫秒
371.
Kim Suk Hyun Ra Kongtae Kim Kyung-Tae Jeong Hyeryeong Lee Jihyun Kang Dong-Jin Rho Taekeun Kim Intae 《Ocean Science Journal》2019,54(4):673-684
Ocean Science Journal - Trace elements (Mn, Fe, Co, Ni, Cu, Zn, etc.) are essential micronutrients for marine organisms and are thus related to major issues in the ocean, such as climate change,... 相似文献
372.
John D. Monnier Stefan Kraus Michael J. Ireland Fabien Baron Amelia Bayo Jean-Philippe Berger Michelle Creech-Eakman Ruobing Dong Gaspard Duchêne Catherine Espaillat Chris Haniff Sebastian Hönig Andrea Isella Attila Juhasz Lucas Labadie Sylvestre Lacour Stephanie Leifer Antoine Merand Ernest Michael Stefano Minardi Christoph Mordasini David Mozurkewich Johan Olofsson Claudia Paladini Romain Petrov Jörg-Uwe Pott Stephen Ridgway Stephen Rinehart Keivan Stassun Jean Surdej Theo ten Brummelaar Neal Turner Peter Tuthill Kerry Vahala Gerard van Belle Gautam Vasisht Ed Wishnow John Young Zhaohuan Zhu 《Experimental Astronomy》2018,46(3):517-529
The Planet Formation Imager (PFI, www.planetformationimager.org) is a next-generation infrared interferometer array with the primary goal of imaging the active phases of planet formation in nearby star forming regions. PFI will be sensitive to warm dust emission using mid-infrared capabilities made possible by precise fringe tracking in the near-infrared. An L/M band combiner will be especially sensitive to thermal emission from young exoplanets (and their disks) with a high spectral resolution mode to probe the kinematics of CO and H2O gas. In this paper, we give an overview of the main science goals of PFI, define a baseline PFI architecture that can achieve those goals, point at remaining technical challenges, and suggest activities today that will help make the Planet Formation Imager facility a reality. 相似文献
373.
Mathematical Geosciences - 相似文献
374.
The network‐time prism (NTP) is an extension of the space‐time prism that provides a realistic model of the potential pattern of moving objects in transportation networks. Measuring the similarity among NTPs can be useful for clustering, aggregating, and querying potential mobility patterns. Despite its practical importance, however, there has been little attention given to similarity measures for NTPs. In this research, we develop and evaluate a methodology for measuring the structural similarity between NTPs using the temporal signature approach. The approach extracts the one‐dimensional temporal signature of a selected property of NTPs and applies existing path similarity measures to the signatures. Graph‐theoretic indices play an essential role in summarizing the structural properties of NTPs at each moment. Two extensive simulation experiments demonstrate the feasibility of the approach and compare the performance of graph indices for measuring NTP similarity. An empirical application using bike‐share system data shows that the method is useful for detecting different usage patterns of two heterogenous user groups. 相似文献
375.
James T. Julian John A. Young John W. Jones Craig D. Snyder C. Wayne Wright 《Journal of Geographical Systems》2009,11(1):89-106
We examined whether spatially explicit information improved models that use LiDAR return signal intensity to discriminate
in-pond habitat from terrestrial habitat at 24 amphibian breeding ponds. The addition of Local Indicators of Spatial Association
(LISA) to LiDAR return intensity data significantly improved predictive models at all ponds, reduced residual error by as
much as 74%, and appeared to improve models by reducing classification errors associated with types of in-pond vegetation.
We conclude that LISA statistics can help maximize the information content that can be extracted from time resolved LiDAR
return data in models that predict the occurrence of small, seasonal ponds.
相似文献
376.
A higher-order non-hydrostatic σ model is developed to simulate non-linear refraction–diffraction of water waves. To capture non-linear (or steep) waves, a 4th-order spatial discretization is utilized to approximate the large horizontal pressure gradient. A higher-order top-layer pressure treatment is further implemented to resolve wave propagation. The model's characteristics including linear wave dispersion and non-linearity are carefully examined. The accuracy of the present model using only two vertical layers is validated by laboratory data and the available results predicted by the non-linear Schrödinger equation, Boussinesq-type equations, the non-linear mild slope equation, and the Laplace equation. Features of harmonic generation as well as the influences of dispersion and non-linearity on wave energy transfer processes are discussed. 相似文献
377.
Growth,feeding and ecological roles of the mixotrophic and heterotrophic dinoflagellates in marine planktonic food webs 总被引:4,自引:0,他引:4
Hae Jin Jeong Yeong Du Yoo Jae Seong Kim Kyeong Ah Seong Nam Seon Kang Tae Hoon Kim 《Ocean Science Journal》2010,45(2):65-91
Planktonic mixotrophic and heterotrophic dinoflagellates are ubiquitous protists and often abundant in marine environments. Recently many phototrophic dinoflagellate species have been revealed to be mixotrophic organisms and also it is suggested that most dinoflagellates may be mixotrophic or heterotrophic protists. The mixotrophic and heterotrophic dinoflagellates are able to feed on diverse prey items including bacteria, picoeukaryotes, nanoflagellates, diatoms, other dinoflagellates, heterotrophic protists, and metazoans due to their diverse feeding mechanisms. In turn they are ingested by many kinds of predators. Thus, the roles of the dinoflagellates in marine planktonic food webs are very diverse. The present paper reviewed the kind of prey which mixotrophic and heterotrophic dinoflagellates are able to feed on, feeding mechanisms, growth and ingestion rates of dinoflagellates, grazing impact by dinoflagellate predators on natural prey populations, predators on dinoflagellates, and red tides dominated by dinoflagellates. Based on this information, we suggested a new marine planktonic food web focusing on mixotrophic and heterotrophic dinoflagellates and provided an insight on the roles of dinoflagellates in the food web. 相似文献
378.
379.
A Tidal Power Plant (TPP) is being constructed in the middle section of the existing Lake Sihwa dike located near the southern Incheon Port in Korea. The project, which will be completed in 2010, is to harness the largest tidal energy in the Kyeonggi Bay in the eastern Yellow Sea. While noting the current progress in terms of plant construction, this paper outlines the overall project in the tidal regime and uses predictive local flow modeling. The results of two-dimensional finite element method simulations that predict the real-time tidal characteristics during the construction and after the completion of the tidal power plant are presented, including a method to estimate the electricity output from the plant in the future. 相似文献