全文获取类型
收费全文 | 224篇 |
免费 | 8篇 |
国内免费 | 5篇 |
专业分类
测绘学 | 15篇 |
大气科学 | 11篇 |
地球物理 | 54篇 |
地质学 | 64篇 |
海洋学 | 40篇 |
天文学 | 47篇 |
综合类 | 1篇 |
自然地理 | 5篇 |
出版年
2023年 | 1篇 |
2021年 | 6篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 11篇 |
2011年 | 10篇 |
2010年 | 19篇 |
2009年 | 19篇 |
2008年 | 14篇 |
2007年 | 12篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有237条查询结果,搜索用时 15 毫秒
51.
Yuri D. Zakharov Yasunari Shiget Kazushige Tanabe Yasuhiro I Olga P. Smyshlyaev Ekaterina A. Sokolov Alexer M. Popov Tatiana A. Velivetskay Tamara B. Afanasyeva 《《地质学报》英文版》2007,81(6):1049-1069
Paleoclimatic settings have been reconstructed for the Campanian using original oxygen-isotopic analyses of well-preserved molluskan and foraminifera shells from Russian Far East, Hokkaido, USA, Belgium and some DSDP holes (95, 98, 102, 390A, and 392A) in North Atlantic. Early Early Campanian climatic optimum has been recognized from data on high bottom shelf water paleotemperatures in middle latitudes of both the western circum-Pacific (to 24.2°C) and the eastern circum-Pacific (to 26.4°C) areas and high bottom shallow water paleotemperatures in high latitudes of the Koryak Upland (22.4–25.5°C), which agrees with the data on the Campanian Barykovskaya flora in high latitudes (Golovneva and Herman, 1998) and Jonker flora and its equivalents in middle latitudes. Judging from the data on comparatively high bottom shallow water paleotemperature values in high latitudes, South Alaska (19.4°C) and the Koryak Upland (22.4–25.5°C), we also expect Latest Campanian temperature maximum, which has not been confirmed, however, for low and middle latitudes by neither of isotopic nor paleobotanic data now. Main climatic tendency during the Campanian (with the exception of Latest Campanian) has been learned from isotopic composition of Campanian aragonitic ammonoid shells from the Hokkaido-South Sakhalin (Krilyon) marine basin. In contrary to Huber’s et al. (2002) assumption, we expect warm greenhouse conditions during the most part of the Campanian. 相似文献
52.
Toshio Fukushima 《Celestial Mechanics and Dynamical Astronomy》1988,45(1-3):73-76
Two extrapolation methods (Gragg's method and GBS method) were tested for the numerical integration of the Keplerian motion. The tests cleared that the Gragg's method is better for the orbit computation and is 1) easy to control, 2) highly accurate, 3) tough, 4) economic, and 5) very flexible against the close encounter. 相似文献
53.
Richard D. Brodeur Joseph P. Fisher Yasuhiro Ueno Kazuya Nagasawa William G. Pearcy 《Journal of Oceanography》2003,59(4):415-434
During the 1980s and 1990s, scientific research cruises were conducted in both the eastern and western boundary regions of
the North Pacific Ocean. The main purpose of these cruises was to examine the abundance and distribution patterns of juvenile
salmon in coastal waters. These studies created one of the most extensive databases ever collected on the species composition
of coastal Transition Zone epipelagic nekton in the North Pacific Ocean. Catch data from two purse seine and two surface trawl
surveys (one each from off northern Japan and eastern Russia and off the West Coast of the U.S.) were examined using multivariate
techniques to analyze the community structure of nektonic cephalopods, elasmobranchs, and teleosts in the coastal zone during
the summer and autumn months. Juvenile salmonids are generally among the most common species caught, but in terms of overall
abundance, other potential competitors with juvenile salmon, such as small squids and clupeoid fishes predominated the catches.
Species diversity and dominance varied among areas and gear types. Distinct assemblages were found in each area, but the two
regions had closely related species occupying similar ecological positions in each habitat.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
54.
Sediments and overlying water collected using Multiple Corer (MC) and Box Corer (BC) at three stations in Suruga Bay were compared from the view points of meiobenthic and chemical characteristics. Dissolved oxygen, pH, ammonium and nitrite concentrations of the overlying waters were lower, whereas nitrate and phosphate concentrations were higher constantly in the samples collected by MC than those by BC, suggesting contamination of surface seawater in the BC samples. Sediments were sliced into 0–1, 1–2 and 2–3 cm layers, and water content and Eh, and abundance of meiofauna were analyzed. Water content in MC samples was always higher than BC ones. For the whole meiobenthos, MC collected significantly more individuals than BC at only one out of three stations, whereas for harpacticoid copepods, which aggregated to the surface layer of the sediment, MC constantly collected significantly more individuals than BC. In the vertical profiles of both water content and meiofaunal density, data of 0–1, and 1–2 cm layers in the BC samples were similar to those of 1–2 and 2–3 cm layers in the MC samples, respectively. These results suggested only MC can collect the real sediment surface (so called fluffy layer), which was lost due to bow wave effects in the BC samples. 相似文献
55.
An Ecosystem Model Including Nitrogen Isotopes: Perspectives on a Study of the Marine Nitrogen Cycle
Chisato?YoshikawaEmail author Yasuhiro?Yamanaka Takeshi?Nakatsuka 《Journal of Oceanography》2005,61(5):921-942
We have developed an ecosystem model including two nitrogen isotopes (14N and 15N), and validated this model using an actual data set. A study of nitrogen isotopic ratios (δ15N) using a marine ecosystem model is thought to be most helpful in quantitatively understanding the marine nitrogen cycle.
Moreover, the model study may indicate a new potential of δ15N as a tracer. This model has six compartments: phytoplankton, zooplankton, particulate organic nitrogen, dissolved organic
nitrogen, nitrate and ammonium in a two-box model, and has biological processes with/without isotopic fractionation. We have
applied this model to the Sea of Okhotsk and successfully reproduced the δ15N of nitrate measured in seawater and the seasonal variations in δ15N of sinking particles obtained from sediment trap experiments. Simulated δ15N of phytoplankton are determined by δ 15N of nitrate and ammonium, and the nitrogen f-ratio, defined as the ratio of nitrate assimilation by phytoplankton to total nitrogenous nutrient assimilation. Detailed
considerations of biological processes in the spring and autumn blooms have demonstrated that there is a significant difference
between simulated δ15N values of phytoplankton, which assimilates only nitrate, and only ammonium, respectively. We suggest that observations of
δ 15N values of phytoplankton, nitrate and ammonium in the spring and autumn blooms may indicate the ratios of nutrient selectivity
by phytoplankton. In winter, most of the simulated biogeochemical fluxes decrease rapidly, but nitrification flux decreases
much more slowly than the other biogeochemical fluxes. Therefore, simulated δ15N values and concentrations of ammonium reflect almost only nitrification. We suggest that the nitrification rate can be parameterized
with observations of δ15N of ammonium in winter and a sensitive study varying the parameter of nitrification rate. 相似文献
56.
Zhigang Sun Qinxue Wang Bunkei Matsushita Takehiko Fukushima Zhu Ouyang Masataka Watanabe 《水文科学杂志》2013,58(5):994-1012
Abstract A simple remote sensing evapotranspiration (ET) model (Sim-ReSET) has been proposed but only tested using field measurements at a site with a semi-arid climate. Its performance for mapping ET using only satellite data remained unknown. In this study, the Sim-ReSET model was further evaluated for ET estimation driven by only MODIS data products. The estimated ET rates were compared with ground-based observational data from a variety of ecosystems and climates across China. The results show that MODIS-based ET estimates are consistent with both the ET measurements from eddy covariance flux towers and those from the Penman-Monteith method combined with micrometeorological data. Evaporation fraction (EF) is indicative of land surface moisture. The derivative EF maps demonstrate that the proposed ET data set obtained from the Sim-ReSET model and MODIS data is capable of capturing the spatio-temporal pattern of land surface moisture for different land covers with different climates. Editor Z.W. Kundzewicz Citation Sun, Z.G., Wang, Q.X., Matsushita, B., Fukushima, T., Ouyang, Z., Watanabe, M., and Gebremichael, M., 2013. Further evaluation of the Sim-ReSET model for ET estimation driven by only satellite inputs. Hydrological Sciences Journal, 58 (5), 994–1012. 相似文献
57.
58.
59.
Philip Lah Jayaram N. Chengalur Frank H. Briggs Matthew Colless Roberto De Propris Michael B. Pracy W. J. G. de Blok Shinobu S. Fujita Masaru Ajiki Yasuhiro Shioya Tohru Nagao Takashi Murayama Yoshiaki Taniguchi Masafumi Yagi Sadanori Okamura 《Monthly notices of the Royal Astronomical Society》2007,376(3):1357-1366
60.
Toshio Fukushima 《Celestial Mechanics and Dynamical Astronomy》2009,105(1-3):245-260
In order to accelerate the numerical evaluation of torque-free rotation of triaxial rigid bodies, we present a fast method to compute various kinds of elliptic functions for a series of the elliptic argument when the elliptic parameter and the elliptic characteristic are fixed. The functions we evaluate are the Jacobian elliptic functions and the incomplete elliptic integral of the second and third kinds regarded as a function of that of the first kind. The key technique is the utilization of the Maclaurin series expansion and the addition theorems with respect to the elliptic argument. The new method is around 25 times faster than the method using the incomplete elliptic integral of general kind and around 70 times faster than the method using mathematical libraries given in the latest version of Numerical Recipes. 相似文献