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181.
Agusa T Yasugi SY Iida A Ikemoto T Anan Y Kuiken T Osterhaus AD Tanabe S Iwata H 《Marine pollution bulletin》2011,62(5):963-975
Body distribution and growth- and nutritional status-dependent accumulation of 21 trace elements were investigated in harbor seals (Phoca vitulina) stranded in the North Sea coast in 2002. Higher concentrations and burdens of Mn, Se, Mo, Ag, Sn, Hg, and Bi in the liver, Cd in the kidney, As in the blubber, and Co, Sr, and Ba in the bone were observed. Significant positive correlations of hepatic Se, Mo, Ag, Cd, Sn, Hg, Tl, and Bi with standard body length were found, while significant negative relationships were detected for Mn, As, Rb, Sr, and Sb in the liver. Concentrations of Co, Se, Sr, Sn, Hg, and Bi in the liver, V, Sr, Ag, Sn, and Hg in the kidney, V, Mn, Co, Rb, Sr, Sn, Ba, and Pb in the blubber increased with decreasing blubber thickness of harbor seals, indicating enrichment of these elements in the target tissue by emaciation. 相似文献
182.
The unsaturated poromechanical behavior of Callovo-Oxfordian argillite (also referred to as Meuse/Haute–Marne argillite) is
analyzed by means of indentation tests at different hygrometries. Numerical simulations carried out with a finite element
code are then used to simulate flat punch indentation tests at different controlled hygrometries. The numerical response F(h) is compared to experimental data in order to estimate the drained Young’s modulus E and the internal friction angle
\Upphi\Upphi (at high confinement) by means of a back analysis. A linear decrease in the drained Young’s modulus and quasi-constant values
of the internal friction angle are observed when the relative humidity ranges. Some predictions of the model are also presented
to quantify the activation of hydraulic phenomena. Indeed, the maximal variation of the saturation and porosity relative to
the initial state of the specimen are lower than 10% and 8%, respectively. 相似文献
183.
Francisco J. Alcalá Yolanda Cantón Sergio Contreras Ana Were Penélope Serrano-Ortiz Juan Puigdefábregas Albert Solé-Benet Emilio Custodio Francisco Domingo 《Environmental Earth Sciences》2011,62(3):541-557
In the high-permeability, semiarid carbonate aquifer in the Sierra de Gádor Mountains (southeastern Spain), some local springs
draining shallow perched aquifers were of assistance in assessing applicability of the atmospheric chloride mass balance (CMB)
for quantifying total yearly recharge (R
T) by rainfall. Two contrasting hydrological years (October through September) were selected to evaluate the influence of climate
on recharge: the average rainfall year 2003–2004, and the unusually dry 2004–2005. Results at small catchment scale were calibrated
with estimated daily stand-scale R
T obtained by means of a soil water balance (SWB) of rainfall, using the actual evapotranspiration measured by the eddy covariance
(EC) technique. R
T ranged from 0.35 to 0.40 of rainfall in the year, with less than a 5% difference between the CMB and SWB methods in 2003–2004.
R
T varied from less than 0.05 of rainfall at mid-elevation to 0.20 at high elevation in 2004–2005, with a similar difference
between the methods. Diffuse recharge (R
D) by rainfall was quantified from daily soil water content field data to split R
T into R
D and the expected concentrated recharge (R
C) at catchment scale in both hydrological years. R
D was 0.16 of rainfall in 2003–2004 and 0.01 in 2004–2005. Under common 1- to 3-day rainfall events, the hydraulic effect of
R
D is delayed from 1 day to 1 week, while R
C is not delayed. This study shows that the CMB method is a suitable tool for yearly values complementing and extending the
more widely used SWB in ungauged mountain carbonate aquifers with negligible runoff. The slight difference between R
T rates at small catchment and stand scales enables results to be validated and provides new estimates to parameterize R
T with rainfall depth after checking the weight of diffuse and concentrated mechanisms on R
T during moderate rainfall periods and episodes of marked climatic aridity. 相似文献
184.
Compression of the thrust sheet underlying the central South Pyrenean Tremp-Graus Foreland Basin led to weak folding of the overlying basin fill during deposition of Eocene sediments. From the distribution of sedimentary facies and the presence of these folds, it is interpreted that thrusting of deep-seated competent units was accommodated by weak synsedimentary folding with a shorter wavelength at shallower levels. This led to differential subsidence at the surface but no unconformities are observed. The slower subsidence along the active anticlines locally influenced the distribution of sedimentary facies: lateral boundaries between different sedimentary facies are found to extend (sub)vertically up to more than 60 metres within narrow zones a few 100 m to 1.5 km wide. The growth folds thus led intermittently to the fixation of the position of facies boundaries, including a fixation of the coastline, over long periods (104 to 105 years). Sediment transport paths were also influenced by the slight folding of the surface. The orientation of the weak ‘en echelon’ anticlines and of related facies boundaries agrees with the inferred compressional pattern during the Eocene. Explanations for the regular occurrence of 50–60 m thick sedimentary cycles in terms of tectonic pulses or orbitally driven climatic changes and resulting pulses in sediment yield are discussed. For cycles of shorter length (10–15 m), with durations of the order of tens of thousands of years, it is inferred that these are due to regular climatic changes, probably related to orbital forcing, and resulting cyclic alternations of arid and wet periods. Such periodic changes of climate would have caused the intermittent waxing and waning of coarse-grained sediment 相似文献
185.
Array Signal Processing for Radio Astronomy 总被引:1,自引:0,他引:1
Radio astronomy forms an interesting application area for array signal processing techniques. Current synthesis imaging telescopes consist of a small number of identical dishes, which track a fixed patch in the sky and produce estimates of the time-varying spatial covariance matrix. The observations sometimes are distorted by interference, e.g., from radio, TV, radar or satellite transmissions. We describe some of the tools that array signal processing offers to filter out the interference, based on eigenvalue decompositions and factor analysis, which is a more general technique applicable to partially calibrated arrays. We consider detection of interference, spatial filtering techniques using projections, and discuss how a reference antenna pointed at the interferer can improve the performance. We also consider image formation and its relation to beamforming. 相似文献
186.
187.
Albert J. Parker 《The Professional geographer》1982,34(3):305-312
Species structural and functional characteristics are used in concert with forest composition to examine links between the physical environment and vegetation along an elevational transect of thirty forest stands in Yosemite National Park, California. The structural/functional approach promotes communication by allowing direct analysis and presentation of ecologically significant information. Patterns of leaf persistence, shade tolerance/twig thickness, and windthrow susceptibility are related to changes along the altitudinal gradient as an illustration of the interpretive capabilities of the technique. 相似文献
188.
Astronomical images currently provide large amounts of data. Lossy compression algorithms have recently been developed for high compression ratios. These compression technique introduce distortion in the compressed images and for high compression ratios, a blocking effect appears. We propose a modified compression algorithm based on the hcompress scheme, and we introduce a new decompression method based on the regularization theory The image is restored scale by scale in a multiresolution scheme and the information lost during the compression is recovered by applying a Tikhonov regularization constraint. The experimental results show that the blocking effect is reduced and some measurements made on a simulated image show that the astrometric and the photometric properties of the restored images are improved. 相似文献
189.
A tow-dimensional finite difference wave propagation code was used to analyse the impact of a rigid, ogival-nosed penetrator with a target consisting of thin alternating layers of silt, sand, and clay. The response of the idealized target was described with an elastic-plastic constitutive model depending upon two stress invariants and the history of plastic deformation. Interfacial friction between the penetrator and target was assumed to be negligible. Comparisons are made of calculated results and those of nominally similar experiments conducted at the Watching Hill test site in Alberta, Canada. Analysis of these comparisons reveals that numerical methods like the one employed in this study can yield insight into penomena, as well as suggesting possible improvements in the calculation technique. 相似文献
190.
Pires C. A. Athayde G. B. de Souza Filho O. A. Ofterdinger U. 《Hydrogeology Journal》2021,29(4):1657-1678
Hydrogeology Journal - Productive regions in the Crystalline Basement Aquifer System (CBAS) in Paraná state, Brazil, were identified qualitatively and quantitatively through spatial... 相似文献