全文获取类型
收费全文 | 502篇 |
免费 | 14篇 |
国内免费 | 4篇 |
专业分类
测绘学 | 7篇 |
大气科学 | 43篇 |
地球物理 | 127篇 |
地质学 | 115篇 |
海洋学 | 82篇 |
天文学 | 128篇 |
综合类 | 2篇 |
自然地理 | 16篇 |
出版年
2023年 | 2篇 |
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 17篇 |
2018年 | 3篇 |
2017年 | 13篇 |
2016年 | 12篇 |
2015年 | 10篇 |
2014年 | 33篇 |
2013年 | 17篇 |
2012年 | 20篇 |
2011年 | 16篇 |
2010年 | 29篇 |
2009年 | 28篇 |
2008年 | 31篇 |
2007年 | 20篇 |
2006年 | 30篇 |
2005年 | 18篇 |
2004年 | 14篇 |
2003年 | 11篇 |
2002年 | 18篇 |
2001年 | 13篇 |
2000年 | 10篇 |
1999年 | 10篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 9篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1977年 | 6篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1963年 | 1篇 |
排序方式: 共有520条查询结果,搜索用时 31 毫秒
391.
Atsushi Toramaru Akira Ishiwatari Maki Matsuzawa Masaru Nakamura Shoji Arai 《Bulletin of Volcanology》1996,58(5):393-400
We report a novel type of layering structure in igneous rocks. The layering structure in the Ogi picrite sill in Sado Island,
Japan, is spatially periodic, and appears to be caused by the variation in vesicle volume fraction. The gas phase forming
the vesicles apparently exsolved from the interstitial melt at the final stage of solidification of the magma body. We call
this type of layering caused by periodic vesiculation in the solidifying magma body "vesicle layering." The presence of vesicle
layering in other basic igneous bodies (pillow lava at Ogi and dolerite sill at Atsumi, Japan) implies that it may be a fairly
common igneous feature. The width of individual layers slightly, but regularly, increases with distance from the upper contact.
The layering plane is perpendicular to the long axes of columnar joints, regardless of gravitational direction, suggesting
that the formation of vesicles is mainly controlled by the temperature distribution in the cooling magma body. We propose
a model of formation of vesicle layering which is basically the same as that for Liesegang rings. The interplay between the
diffusion of heat and magmatic volatiles in melt, and the sudden vesiculation upon supersaturation, both play important roles.
Received: 15 February 1996 / Accepted: 24 June 1996 相似文献
392.
Mass movements caused by recent tectonic activity: The 1999 Chi-chi earthquake in central Taiwan 总被引:10,自引:0,他引:10
Wen-Neng Wang Huei-Long Wu Hiroyuki Nakamura Shang-Chih Wu Shoung Ouyang Ming-Fang Yu 《Island Arc》2003,12(4):325-334
Abstract The Chi‐chi earthquake (MS = 7.7), which occurred in September 1999, seriously damaged central Taiwan. Approximately 2 years later (July 2001), the Toraji typhoon brought a heavy rainstorm (650 mm rain/day) and triggered widespread landslides in central Taiwan and parts of eastern Taiwan. Approximately 10 000 Chi‐chi earthquake‐induced landslides and 6000 Toraji typhoon‐related mass movements were delineated in an area of 2400 km2 using Satellite Pour l’Observation de la Terre (SPOT; French earth resource satellite) images. The landslide distribution could be closely related to the distribution of peak ground acceleration registered during the Chi‐chi earthquake. The study area was composed of Tertiary sedimentary and metamorphic rocks, whose age and induration increased eastward. The earthquake‐induced landslides were mostly distributed in the region between the Chelungpu Fault and the Lishan Fault to the east, whereas they were few in the region east of the Lishan Fault. The Toraji typhoon in 2001 severely damaged both regions that had been shattered by the Chi‐chi earthquake in 1999. The occurrence of earthquake‐induced landslides can be correlated with epicentral distance, and their occurrence has more influence from the rock type than from the ground motion. 相似文献
393.
The materials were obtained from the survey conducted in the Kuroshio area of the East China Sea to the Southwest of Kyushu in Japan (29°30'-32°00', 128°00'-130°'00'E) on board the R. V. Yoko Maru of Seikai Regional Fisheries Lab, Fisheries Agency, Japan in June 15~28, 1988 during China-Japan Joint Research on the Kuroshio. Zoo-plankton was collected by means of the North Pacific Net with model TSK flowmeter through vertical haul from 50 -Om. Temperature and salinity were measured with CTD. 134 species (including 4 spp. ) of planktonic copepods were preliminarily identified in the survey area. Most of them belonged to the tropical and subtropical species and a few of them were the warm-temperate species and eurytopic species. The main dominant species vteieOncaea venusta, Oithona plumifera, Clausocalanus furcatus, C. Arcuicornis, Paracaianus dculeatus, Oithona similis, Temara turbinata, Oncaea media, Undinula danvinii, Acartia negligent, Corycaeus speciosus, Scolecithrix danae, etc. The total number 相似文献
394.
90Sr and137Cs concentrations and their vertical distributions were determined in deep waters in the western Northwest Pacific, including the adjacent seas of Japan, from 1976 to 1979.The profiles of the radionuclides show distribution patterns with two parts with an exponential variation of radioisotope content with depth in both parts.Generally speaking, the inventories of90Sr and137Cs in the open waters of the northwestern Pacific correspond fairly well to the fallout inputs, but in some circumstances there seems to be considerable removal of radionuclides from the water column or they are diluted with water of lower radioactivity from other regions.The possibility of radioisotope remobilization from the bottom sediment or particulate matter is also discussed. 相似文献
395.
The countries surrounding the Northwest Pacific marginal seas have different levels of economic development and different political systems. With the rapid economic development in the region, the marine environment received high pressure, which requires high attention of the governments concerned, and urgent actions.As the Northwest Pacific marginal seas shared by several countries, regional co-operation and co-ordination are the effective means to address the marine environmental problems in the region. The Northwest Pacific Action Plan, the Northeast Asian Regional GOOS are providing the intergovernmental mechanism to facilitate the regional co-operation and co-ordination. Effective implementation of these projects is a critical task facing to all countries in the region. 相似文献
396.
Shigehisa Nakamura 《Journal of Oceanography》1977,33(1):47-53
By a model bay with a mouth and a narrow, an experiment on long period waves is carried out to discuss the behavior of the tsunamis and storm surges. Emphasis is placed on the analysis of the characteristics of the current velocities associated with the long period waves incoming through the mouth in terms of Ursell's parameter. 相似文献
397.
Further studies on the transport in sea water and accumulation in marine sediment of the radionuclides, released from a nuclear power plant, on Urazoko Bay, Fukui Prefecture were reported.The partition of radionuclides among the particle size fractions of a sediment sample indicated that the accumulation of60Co,137Cs and54Mn in the sediment were dominated substantially by the sorption on the particle surface in sea water, and the patterns of their sorption were considerably similar to each other.In regard to the60Co contamination of marine sediments in an area of about 13 km2 around the nuclear power plant, 60% of the60Co contamination were retained in Urazoko Bay, which occupies only 7% of the bottom surface of the region.It is clear that a part of60Co accumulated in the sediment of Urazoko Bay gradually moved to the outerward. 相似文献
398.
An artificial beach has been constructed compensating for losing of the natural one caused by the development of coastal area. In this paper, the hydraulic model tests are carried out to investigate the suction phenomenon on the artificial beach constituted of rubble mound breakwater with gravel and the reclaimed sand area. In addition, the numerical model for waves, structures and seabed interaction as well as the numerical method based on the u–p approximation of the Biot equations is developed for investigation of suction mechanism. After verification of the numerical models by comparing numerical results with experimental data, the numerical models are further used to clarify the detailed suction mechanism of the reclaimed sand. The factors that affect the suction phenomenon are examined experimentally and their critical values are presented. Also, it can be pointed out that the vertical discharge velocity as well as the volumetric strain around the still water level of the boundary between the breakwater and the beach gets up to the critical value, the reclaimed sand starts to flow out to the offshore, and it finally leads to caves and cave-ins in the reclaimed zone. 相似文献
399.
400.
Yasuo Nakamura 《Journal of Oceanography》1985,41(6):381-387
Chattonella antiqua was grown in a nitrogen- or phosphorus-limited semicontinuous culture system. Using the cells in steady growth state, the relationship between growth rate and cell quota and effects of growth conditions on nitrate, ammonium and phosphate uptake were examined. Under nitrogen-limited conditions, growth rate as a function of nitrogen cell quota followed the empirical Droop equation and the uptake of nitrate and ammonium was not significantly affected by growth rate. Similarly, under phosphorus-limited conditions, the growth rate as a function of phosphorus cell quota also followed the Droop equation and phosphate uptake was not significantly affected by growth rate.Combining the results obtained in the present study with those from previous studies on nutrient uptake, half saturation constants for growth (K
g
) were calculated for nitrate, ammonium and phosphate. Comparisons ofK
g
with nutrient concentrations in the Seto Inland Sea in summer, where red tides ofC. antiqua often occur, suggest that phosphate is one of the controlling factors for the population ofC. antiqua. 相似文献