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141.
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143.
Abdur Razzak Kenji Jinno Yoshinari Hiroshiro Md. Abdul Halim Keita Oda 《Environmental Geology》2009,58(3):459-469
A one dimensional reactive transport model was developed in order to illustrate the biogeochemical behavior of arsenic and
iron reduction and release to groundwater that accounts for the reaction coupling the major redox elements under reducing
environment. Mass transport equation and the method of characteristics were used considering fundamental geochemical processes
to simulate transport processes of different pollutants in mobile phase. The kinetic sub-model describes the heterotrophic
metabolisms of several microorganisms. To model a complete redox sequence (aerobic or denitrifiers, Fe(III)-reduction, respiration
bacteria of iron and arsenic compounds, and As(V) reduction) four functional bacterial groups (X
1, X
2, X
3, and X
4) were defined. Microbial growth was assumed to follow Monod type kinetics. The exchange between the different phases (mobile,
bio, and matrix) was also considered in this approach. Results from a soil column experiment were used to verify the simulation
results of the model. The model depicts the utilization of oxygen, nitrate, iron oxide and arsenic as electron acceptors for
oxidation of organic carbon (OC) in a column. The OC as electron donor is one of the most important factors that affect the
iron and arsenic reduction bacterial activity. 相似文献
144.
The following work aims at minimizing the environmental impact of the solid wastes (ash) that is produced after the utilization
of the bituminous limestone in thermal power stations and/or retorting processes. The laboratory tests have been selected
with respect to construction needs and possible post construction conditions. Utilization of the various types of ash in the
production of lightweight concrete block has revealed optimum results. The compressive strength of various ash–glass sand
mixes has ranged between 19 and 76 kg/cm2 at 28 days. The compressive strength of ash–tuff mixes has ranged between 54 and 63 kg/cm2 at 28 days. Ultra light mixtures using ash–polyester with a density of 0.88 kg/m3 and a compressive strength of 21 kg/cm2 at 28 days are produced at normal room curing temperature without the use of ordinary Portland cement. The high alkalinity
of El-Lajjun ash is considered a disadvantage when utilized in normal concrete mixes for structural purposes. Ash only can
be mixed with aggregates to produce lean concrete for blinding purposes for use in foundations. 相似文献
145.
J. Prieto M. Böhme H. Maurer K. Heissig H. Abdul Aziz 《International Journal of Earth Sciences》2009,98(7):1767-1791
The Early to Middle Miocene Fluviatile Untere Serie lithostratigraphic unit of the Upper Freshwater Molasse (UFM) in the North
Alpine Foreland Basin (NAFB) crops out in a 40 m long section at Untereichen-Altenstadt (central part of the NAFB). This section
yields a unique superposition of two vertebrate assemblages belonging to different biostratigraphic units: early part OSM
C + D (Karpatian) and OSM E (Early Badenian). Detailed taxonomic analyses reveal different diversity patterns in the two assemblages.
Nine small mammal and six ectothermic vertebrate taxa occur in the older level UA 540 m, while 20 small mammal and 23 ectothermic
vertebrate taxa are recorded for the younger level UA 565 m. From the latter locality comes a small-sized representative of
the biostratigraphically significant Megacricetodon lappi lineage. This evolutionary level has not been documented previously for the eastern part of the NAFB. Bioclimatic analysis
combined with lithofacies and architectural element analysis indicates that significant changes in the fluvial sedimentation
style, surface-water runoff and tectonics occurred between the Early Karpatian and Early Badenian. A meandering fluvial system
(marly unit) is erosively overlain by sandy braided river deposits (sandy unit). Overbank deposits of the marly unit revealed
that the older vertebrate fossil assemblage (UA 540 m) is deposited in an animal burrow that was presumably produced by owls.
Both reptilian and mammalian taxa are indicative of a relatively open environment and dry, probably semi-arid climate. Conversely,
vertebrates from the sandy unit (UA 565 m), which are accumulated in channel fill deposits, suggest closed as well as open
habitats with a subtropical humid climate and mean annual rainfall of about 1,000 mm. According to the sequence stratigraphic
analysis the marly unit is interpreted as a highstand-system-tract of the TB 2.2 global 3rd order sequence. The new results
add support to the hypothesis that the erosional unconformity between both sedimentary units spanning the Karpatian-Badenian
transition corresponds to the pre-Riesian hiatus, which has been interpreted as part of the Styrian Tectonic Phase, and was
previously identified only in the eastern and northeastern part of the NAFB. The biostratigraphic data further indicate that
this hiatus lasted longer in the eastern than in the central part of the basin. 相似文献
146.
D.Malleswari K.Veeraswamy K.K.Abdul Azeez A.K.Gupta Narendra Babu Prasanta K.Patro T.Harinarayana 《地学前缘(英文版)》2019,10(5):1915-1930
Broad-band and long period magnetotelluric measurements made at 63 locations along ~500 km long Chikmagalur-Kavali profile,that cut across the Dharwar craton(DC)and Eastern Ghat Mobile Belt(EGMB)in south India,is modelled to examine the lithosphere architecture of the cratonic domain and define tectonic boundaries.The 2-D resistivity model shows moderately conductive features that intersperse a highly resistive background of crystalline rocks and spatially connect to the exposed schist belts or granitic intrusions in the DC.These features are therefore interpreted as images of fossil pathways of the volcanic emplacements associated with the greenstone belt and granite suite formation exposed in the region.A near vertical conductive feature in the upper mantle under the Chitradurga Shear Zone represents the Archean suture between the western and eastern blocks of DC.Although thick(~200 km)cratonic(highly resistive)lithosphere is preserved,significant part of the cratonic lithosphere below the western DC is modified due to plume-continental lithosphere interactions during the Cretaceous—Tertiary period.A west-verging moderately conductive feature imaged beneath EGMB lithosphere is interpreted as the remnant of the Proterozoic collision process between the Indian land mass and East Antarctica.Thin(~120 km)lithosphere is seen below the EGMB,which form the exterior margin of the India shield subsequent to its separation from East Antarctica through rifting and opening of the Indian Ocean in the Cretaceous. 相似文献
147.
Antiplane response of a dike with flexible soil-structure interface to incident SH waves 总被引:2,自引:0,他引:2
Abdul Hayir Maria I. Todorovska Mihailo D. Trifunac 《Soil Dynamics and Earthquake Engineering》2001,21(7)
Studies of the effects of differential ground motions on structural response generally do not consider the effects of the soil-structure interaction. On the other end, studies of soil-structure interaction commonly assume that the foundation of the structure (surface or embedded) is rigid. The former ignore the scattering of waves from the foundation and radiation of energy from the structure back to the soil, while the latter ignore quasi-static forces in the foundations and lower part of the structure deforming due to the wave passage. This paper studies a simple model of a dike but considers both the soil-structure interaction and the flexibility of the foundation. The structure is represented by a wedge resting on a half-space and excited by incident plane SH-waves. The structural ‘foundation’ is a flexible surface that can deform during the passage of seismic waves. The wave function expansion method is used to solve for the motions in the half-pace and in the structure. The displacements and stresses in the structure are compared with those for a fixed-base model shaken by the free-field motion. The results show large displacements near the base of the structure due to the differential motion of the base caused by the wave passage. 相似文献
148.
Sardar Md Abdul Jabber Yusuf Sharif Ahmed Khan M. Saifur Rahman 《Marine pollution bulletin》2001,42(12)
Levels of organochlorine pesticide residues (p,p′ DDT, DDD, DDE, Aldrin, Dieldrin, Lindane, Heptachlor and BHC) were analysed in the dry and wet seasons in four organs (muscle, liver, gut and egg samples) of Ganges Perch, Lates calcarifer, collected during October–November–December, 1996 and May–June–July, 1997 from the Ganges–Brahmaputtra–Meghna estuary. The residues were analysed by using gas-chromatography (GC) in electron capture detector (ECD) mode and were verified by thin layer chromatography (TLC). Among the four organs analysed, the residues were found in the order egg > gut > muscle > liver. The pesticide residues were found in the order ∑DDT > Heptachlor >Dieldrin > Aldrin. Higher levels of residues were found during the dry season due to high lipid content in fishes. A positive correlation was observed between the pesticide residues (∑DDT and ∑OCs) and lipid contents of fish, and the correlation was found to be linear. The concentrations of pesticide residues in muscle, liver and gut were below the FAO/WHO (1993) recommended permissible limit except in eggs. 相似文献
149.
150.
Abdul S. Abdul 《Ground Water Monitoring & Remediation》1992,12(1):105-114
More than 200,000 gallons of automatic transmission fluid (ATF) leaked from an underground storage tank system and contaminated an area of about 64,000 ft2 of a soil and ground water system. A pumping strategy for improved drainage and recovery of free oil was developed, tested in a laboratory model aquifer, and implemented and evaluated at the field site. This pumping strategy differs from conventional approaches in two important ways: (1) The oil recovery rate is carefully controlled to maximize the pumping rate while maintaining continuity between the oil layer in the soil and the recovery well, to avoid isolation of the oil in the subsurface; and (2) The rate of ground water pumping is controlled to maintain the depressed oil/water interface at its prepumped position. This approach prevents further spread of oil into the ground water, prevents reduction in the volume of recoverable oil due to residual retention, and maintains a gradient for oil flow toward the recovery well. In a model aquifer study, nearly 100 percent of the recoverable volume of ATF was pumped from the system, and about 56,000 gallons of the ATF has been recovered from the field site. 相似文献