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231.
The energy dissipation capacity of a structure is a very important index that indicates the structural performance in energy‐based seismic design. This index depends greatly on the structural components that form the whole system. Owing to the wide use of the strong‐column weak‐beam strength hierarchy where steel beams dissipate the majority of earthquake input energy to the structures, it is necessary to evaluate the energy dissipation capacity of the beams. Under cyclic loadings such as seismic effects, the damage of the beams accumulates. Therefore, loading history is known to be the most pivotal factor influencing the deformation capacity and energy dissipation capacity of the beams. Seismic loadings with significantly different characteristics are applied to structural beams during different types of earthquakes and there is no unique appropriate loading protocol that can represent all types of seismic loadings. This paper focuses on the effects of various loading histories on the deformation capacity and energy dissipation capacity of the beams. Cyclic loading tests of steel beams were performed. In addition, some experimental results from published tests were also collected to form a database. This database was used to evaluate the energy dissipation capacity of steel beams suffering from ductile fracture under various loading histories. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
232.
Satoshi Fujita Keisuke Minagawa Go Tanaka Haruo Shimosaka 《Soil Dynamics and Earthquake Engineering》2011
Recently strong seismic waves or long period seismic waves have been observed in various earthquakes that occurred in Japan. As a result improvements of existing seismic isolation systems are deemed necessary. The present study proposed an intelligent seismic isolation system encompassing air bearings and earthquake early warning (EEW) system. Such system exhibits adequate isolation performance. The air bearings are isolation device that may render infinite the superstructure natural period by floating them, and the EEW is applied for a trigger of isolation. This paper illustrates the proposed system and discusses the experimental results of a test carried out with the system. Laboratory tests carried out in the present research demonstrate the effectiveness of the proposed base isolated systems and prove its efficacy in mitigating the effects of three-dimensional seismic waves. For example, the system suppressed the horizontal response acceleration of an isolation target to 38% of input acceleration. 相似文献
233.
Takeru Moriyama Ritsuro Miyawaki Kazumi Yokoyama Satoshi Matsubara Hideo Hirano Hiroyasu Murakami Yasushi Watanabe 《Resource Geology》2011,61(1):101-110
Wakefieldite‐(Nd), NdVO4, is a new mineral found from the Arase stratiform ferromanganese deposit in Kochi Prefecture, Shikoku Island, Japan. It is the Nd‐dominant analogue of wakefieldite‐(Y) and wakefieldite‐(Ce). The ferromanganese ore specimen mainly consists of hematite and caryopilite, and wakefieldite‐(Nd) is typically enclosed in caryopilite. Wakefieldite‐(Nd) is tetragonal, I41/amd, a = 7.338(16) Å, c = 6.509(19) Å, V = 350.5(18) Å3, Z = 4. The four strongest lines in the X‐ray diffraction pattern [d(Å), I/I0, hkl] using a Gandolfi camera are (3.67, 100, 200); (2.74, 51, 112); (4.84, 27, 101) and (1.89, 25, 312). Chemical composition of wakefieldite‐(Nd) are V2O3 35.25, As2O3 0.93, SiO2 0.14, MnO 1.45, Fe2O3 0.41, Y2O3 2.87, La2O3 7.61, Ce2O3 7.37, Pr2O3 6.04, Nd2O3 26.79, Sm2O3 4.41, Eu2O3 1.36, Gd2O3 3.41, Tb2O3 0.22, Dy2O3 1.41, Er2O3 0.10, total 99.77 wt.%. The empirical formula is (Nd0.403La0.118Ce0.114Pr0.093Y0.064Sm0.064Mn0.052Gd0.048Eu0.020Dy0.019Fe0.013Tb0.003Er0.001)1.012(V0.981As0.020Si0.006)1.007O4 on the basis of O = 4. The calculated density is 4.782 g/cm3. Microtexture and co‐existing relationship between wakefieldite‐(Nd) and caryopilite suggest that recrystallization and dehydration of Fe‐ and Mn‐oxyhydroxide led to the generation of hematite, caryopilite, rhodochrosite and wakefieldite‐(Nd) by the metamorphism during the accretion of the host unit of the Arase deposit. Chondrite‐normalized REE pattern of the host ferromanganese ore, which is regarded as oceanic metalliferous sediment in origin, shows negative Ce anomaly. Chemical composition of wakefieldite‐(Nd) reflects Ce‐depleted bulk composition of REE‐enriched ferromanganese ore. 相似文献
234.
Koichi Ara Koh Yamaki Keisuke Wada Satoshi Fukuyama Takeshi Okutsu Sadao Nagasaka Akihiro Shiomoto Juro Hiromi 《Journal of Oceanography》2011,67(1):87-111
Seasonal and interannual variations in physicochemical properties (i.e., temperature, salinity, dissolved oxygen and dissolved
inorganic nutrients), chlorophyll a (Chl-a), particulate carbon and nitrogen (PC and PN, respectively), and primary production were investigated in the neritic area
of Sagami Bay, Kanagawa, Japan, from January 2002 to December 2008. These abiotic/biotic variables, except for NH4
+–N, repeated similar seasonal variations for all 7 years. On the basis of the analysis of data obtained on 167 sampling dates,
depth-integrated primary production in this water can be easily estimated from Chl-a at the surface using the regression equations obtained in the present study. Intermittently high values of dissolved inorganic
nutrients, Chl-a, PC, PN and primary productivity at the surface during the summer stratified period were induced by high freshwater discharge
from the rivers after rainfalls and by the expansion of nutrient-rich Tokyo Bay Water. Temperature, salinity and dissolved
inorganic nutrients showed drastic variations within a scale of a few days and/or weeks, and these variations were related
to sea levels that represent the intrusion of the Kuroshio Water, Intermediate Oyashio Water or deep water from the continental
slope. However, there was no consistent trend in the variations in Chl-a, PC, PN and primary production due to the complex effects of these waters. 相似文献
235.
The Adachi-Medeshima pumice deposit of the Late Pleistocene age, found in Northeast Japan, contains extremely low-K tonalite fragments, having a wide variation in SiO2 content but fairly uniform K2O content (<0.1%). The tonalites coexist with essential dacite fragments. Mineralogical properties of the tonalites are the same as those of the pumice and dacite fragments. Sr isotope ratios of the tonalite, dacite fragments and pumice also fall within a narrow range. By assuming a Rayleigh fractionation model, the concentration of incompatible trace elements in cumulus phases was calculated, and the amounts of major elements were estimated from the fractionation ratios of each mineral and the volume ratio of crystal-liquid. The estimated element abundances of the cumulus phase show a MORB normalized pattern similar to that of the natural tonalite having cumulate textures. Thus, the tonalite represents the cumulus phase precipitated from dacite magma. Equilibrium temperatures and fO2 of the tonalites, dacite fragments and pumice were estimated from coexisting magnetite-ilmenite pairs at 876°–796° C and –logfO2 = 9.8–11.9, respectively. The fO2 is among highest group yet reported. This is a case of extremely low-K tonalite which formed in the island arc system different from the oceanic environments. 相似文献
236.
渤海西岸平原海平面上升危害性评估 总被引:14,自引:3,他引:14
本文按照IPCC第三工作组海岸管理小组拟定的国际共同研究大纲与方法,在对渤海西岸平原海平面上升的危害性进行评估时,应用TM遥感影像与地理信息系统,由土地利用类型、海岸蚀积动态叠加1─6m等高线编制成环境地形图,再与地面形变图等辅助图件对照分析,预测海平面上升对环境和社会经济的危害。 相似文献
237.
238.
Osama Eljamal Junya Okawauchi Kazuaki Hiramatsu Masayoshi Harada 《Environmental Earth Sciences》2013,68(3):859-863
The sorption of phosphorus by using four different natural materials (marble dust, sawdust, soil, and rice husk) was studied by conducting batch tests and kinetic sorption model. The kinetic sorption model based on a pseudo equation was applied to predict the rate constant of sorption. Thorough investigations to understand the mechanism of phosphorus sorption onto the natural materials using kinetic sorption models, pseudo first- and second-order kinetic sorption model showed that the kinetic sorption is consistent with the second-order model, from which it can be inferred that the mechanism of sorption is chemisorption. Batch tests and kinetic sorption model results showed that by using marble dust as sorbent, among other materials, could remove more than 93 % of phosphorus from aqueous solution. 相似文献
239.
Development of a numerical model for nitrates in groundwater in the reservoir area of the Komesu subsurface dam, Okinawa, Japan 总被引:1,自引:0,他引:1
Shuhei Yoshimoto Takeo Tsuchihara Satoshi Ishida Masayuki Imaizumi 《Environmental Earth Sciences》2013,70(5):2061-2077
A numerical model consisting of simplified equations was developed to simulate nitrate concentrations in groundwater in a reservoir area of a subsurface dam in a Quaternary limestone region. The model was composed of a water balance sub-model and a nitrogen balance sub-model; the water balance sub-model was built from tank models which can express the quick dilution near caves and the effect of dam construction; and the nitrogen balance sub-model was made to represent changes in nitrogen forms and movement of nitrogen in the soil and aquifer zones. The model was calibrated and verified by observed data before and after the dam construction and then applied to a predictive simulation under a simple assumption that rainfall descends gradually. The model seemed applicable to long-term prediction of changes in NO3-N in the reservoir area. 相似文献
240.
Michael E. Jones Alastair C. Edge Keith Grainge William F. Grainger Rüdiger Kneissl G. G. Pooley Richard Saunders Shigeru J. Miyoshi Taisuke Tsuruta Koujun Yamashita Yuzuru Tawara Akihiro Furuzawa Akihiro Harada Isamu Hatsukade 《Monthly notices of the Royal Astronomical Society》2005,357(2):518-526
We have observed the Sunyaev–Zel'dovich (SZ) effect in a sample of five moderate-redshift clusters with the Ryle Telescope, and used them in conjunction with X-ray imaging and spectral data from ROSAT and ASCA to measure the Hubble constant. This sample was chosen with a strict X-ray flux limit using both the Bright Cluster Sample and the Northern ROSAT All-Sky Survey (RASS) cluster catalogues to be well above the surface brightness limit of the RASS, and hence to be unbiased with respect to the orientation of the cluster. This controls a major potential systematic effect in the SZ/X-ray method of measuring H 0 . Taking the weighted geometric mean of the results and including the main sources of error, namely the noise in the SZ measurement, the uncertainty in the X-ray temperatures and the unknown ellipticity and substructure of the clusters, we find H 0 = 59+10 −9 (random)+8 −7 (systematic) km s−1 Mpc−1 assuming a standard cold dark matter model with ΩM = 1.0, ΩΛ = 0.0 or H 0 = 66+11 −10 +9 −8 km s−1 Mpc−1 if ΩM = 0.3, ΩΛ = 0.7 . 相似文献