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981.
982.
Michael J. Hollaway Keith J. Beven Clare Mc W. H. Benskin Adrian L. Collins Robert Evans Peter D. Falloon Kirsty J. Forber Kevin M. Hiscock Ron Kahana Christopher J. A. Macleod Mary C. Ockenden Martha L. Villamizar Catherine Wearing Paul J. A. Withers Jian G. Zhou Nicholas J. Barber Philip M. Haygarth 《水文研究》2018,32(17):2779-2787
River discharge and nutrient measurements are subject to aleatory and epistemic uncertainties. In this study, we present a novel method for estimating these uncertainties in colocated discharge and phosphorus (P) measurements. The “voting point”‐based method constrains the derived stage‐discharge rating curve both on the fit to available gaugings and to the catchment water balance. This helps reduce the uncertainty beyond the range of available gaugings and during out of bank situations. In the example presented here, for the top 5% of flows, uncertainties are shown to be 139% using a traditional power law fit, compared with 40% when using our updated “voting point” method. Furthermore, the method is extended to in situ and lab analysed nutrient concentration data pairings, with lower uncertainties (81%) shown for high concentrations (top 5%) than when a traditional regression is applied (102%). Overall, for both discharge and nutrient data, the method presented goes some way to accounting for epistemic uncertainties associated with nonstationary physical characteristics of the monitoring site. 相似文献
983.
Poecilia reticulata PETERS (guppy) and the green alga Monoraphidium griffithii were used for testing of different fluorotensides. After the representation of the methods of investigation and the definition of criteria of toxicity the obtained results of investigation are discussed. In general, the toxicity of the four investigated fluorotensides to algae was lower than to fish. The anionic fluorotenside CF3—(CF2)n—CFH—COONa was an exception. In tables and diagrams the results are summarized. Finally, for the condition of the receiving-water biocenosis class “2” the respective still permissible matter concentrations are proposed. They vary between 0.05 and 0.2 mg/1. 相似文献
984.
ISLA will be an astronomical observatory, operating at the upper limit of our planet Earth atmosphere, offering space like
observing conditions in most aspects. ISLA can be maintained easily, modified easily if necessary, always kept at the state
of the art and operated for very extended periods without polluting the stratosphere. ISLA is ideally suited to become the
first world space observatory as the observing conditions are very much space-like – diffraction limited angular resolution,
very low ambient temperature, remote control – however ISLA is easily accessible, telescopes and instruments can be continuously
improved and ISLA's costs corresponds only to those of ground-based modern astronomical installations like the ESO-VLT-, KECK-
and GEMINI-observatories. The cost of observing and experimenting on ISLA will be orders of magnitudes lower than those of
building and operating any space telescope, allowing the astronomers of developing nations to participate in the ISLA observatory
within their limited financial possibilities as competent and full partners. ISLA's 4-m and 2-m telescopes will operate diffraction
limited from 0.3 μm in the optical, over the infrared, far-infrared to the sub-mm spectral range. ISLA's individual telescopes
will permit imaging with 20 milli-arcsec spatial resolution in the optical, 5 times better than the Hubble Space Telescope.
ISLA's telescopes can be combined to form an interferometer with a maximum baseline of 250 m with nearly complete coverage
of the u,v plane. Interferometric resolution will be of the order of 20 micro-arcsec for the optical. ISLA will thus offer
spatial resolution comparable or better than the intercontinental VLBI radio interferometers. ISLA's telescope efficiency
will be many orders of magnitude better than comparable ground-based telescopes. The light collecting power of ISLA's interferometric
telescopes will be orders of magnitudes greater than the future space interferometers under discussion. ISLA, being an aviation
project and not a space project, can be realised in the typical time scale for the development of aviation: about 5 years.
ISLA's cost for the whole observatory, including its movable ground station etc. will be of the order of a typical medium
size ESA space mission. ISLA's lifetime will be in excess of many decades, as it can easily be maintained, modernised, repaired
and improved. ISLA will become the origin of a new astronomical international organisation with worldwide participation. ISLA's
telescopes will be of the greatest importance to all astronomical fields, as it will permit to study much fainter, much more
distant objects with microscopic spatial resolution in wavelength regions inaccessible from ground. ISLA's many telescopes
permit easily simultaneous observations at many wavelengths for rapidly varying objects, from continuously monitoring the
surfaces of the planets in our solar system, surfaces of close-by stars, nuclei of galaxies to QSO's.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
985.
Milan M. Ćirković 《Astrophysics and Space Science》2003,283(2):273-277
The existence of rotation signatures in damped Lyαabsorption systems represents a crucial test of the hypothesis that these features arise in disks of normal spiral galaxies. We apply the method for evaluating such signatures to the metal absorption lines in QSO 0528-250. In particular, the systemic redshift of the absorber is inferred from the recent detection of emission in the absorber by Möller and Warren. The kinematics of this absorber are particularly interesting because molecular hydrogen, the densest ISM component of the assumed foreground absorbing galaxy, is detected. Contrary to a recent claim, the method yields a satisfactory value for the assumed rotation velocity of the absorber. 相似文献
986.
S. Kida K. Niinuma S. Suzuki T. Tanaka R. Nakanura K. Takefuji N. Matsumura M. Kuniyoshi T. Daishido 《New Astronomy》2008,13(7):519-525
The Nasu Observatory, which is composed of eight 20 m elements, was constructed for observing radio transients over a wide field at 1400 MHz. We report on two radio transients detected in consecutive drift scanning observations at declination 32° over a period of about two months. One of the two transients, WJN J1039+3200, appeared at =10h39m40s±10s, δ=32°±0.4° on March 4, 2005, and the other one, WJN J0645+3200, appeared at =06h45m25s±10s, δ=32°±0.4° on March 24, 2005. Both exhibited flux densities in excess of 1 Jy, and the burst durations were up to two days. Since there are few examples of radio transients outside the Galactic plane, these are very important observations. We have previously reported on four radio transients with features that look like the two transients detected this time. Of these six WJN transients in total, five had a duration of up to two days, and one up to three days. Four of the transients were detected at high Galactic latitude of b > 30°. Counterparts of the six WJN transients included X-ray sources in four events and had a consistency of 66%. The consistency of γ-ray, PGC Galaxy, NVSS, and FIRST sources was concentrated at about 50%. We were not able to find any special features in the counterparts. The distribution was verified by making a log N–log S plot using data for the four previously detected transients and the new ones. As a result, the distribution of the radio transients that we observed might have an isotropic distribution not dependent on Galactic longitude and Galactic latitude. The detection probability was calculated based on the assumption of an isotropic distribution. The 2σ upper probability limit for detection of transients of 1000 mJy or more is 0.0049 [deg−2 yr−1]. We cannot yet identify these two radio transients, because their features are different from any radio bursts observed in the past. 相似文献
987.
M.A. Etheridge 《Tectonophysics》1975,25(1-2)
The microstructures and fabrics of naturally deformed orthopyroxenites from the Giles Complex, central Australia are described in some detail. Coarse grained enstatite is deformed and recrystallised where it is incorporated in planar gneissic (mylonite) zones which show a gradation in strain from their margins inwards. Deformation takes place by slip on (100) [001] to produce regular lattice bending and kinking, and recrystallisation takes place preferentially along grain boundaries and kink band boundaries (KBB's). The microstructures and preferred orientation of recrystallised grains along KBB's are interpreted in terms of possible nucleation mechanisms, and both bulge nucleation (Bailey and Hirsch, 1962) and subgrain coalescence (Hu, 1963) are likely contributors. Electron microprobe analyses have indicated a small compositional difference between new (recrystallised) and host (deformed) grains, which is related to the nucleation mechanism. The total preferred orientation patterns for host and new grains are discussed with special reference to previous measurements and interpretations. 相似文献
988.
In the first part of this study, a series of stress-controlled hollow cylinder cyclic torsional triaxial shear tests were conducted on loose to medium dense saturated samples of clean Toyoura sand to investigate its liquefaction behavior. A uniform cyclic sinusoidal loading at a 0.1 Hz frequency was applied to air-pluviated samples where confining pressure and relative density was varied. Cyclic shear stress–strain changes, the number of cycles to reach liquefaction and pore pressure variations were recorded. Results indicate that the liquefaction resistances of uniform sands are significantly affected by the method of sample preparation and initial conditions. 相似文献
989.
Reinforced concrete columns with insufficient transverse reinforcement and non‐seismic reinforcement details are vulnerable to brittle shear failure and to loss of axial load carrying capacity in the event of a strong earthquake. In this paper, a procedure is presented after examining the application of two macro models for displacement‐based analysis of reinforced concrete columns subjected to lateral loads. In the proposed model, lateral load‐deformation response of the column is simulated by estimating flexural and shear deformation components separately while considering their interaction and then combining these together according to a set of rules depending upon column's yield, flexural and shear strengths. In addition, lateral deformation caused by reinforcement slip in beam–column joint regions and buckling of compression bars are taken into account and considered in the analysis. Implementation of the proposed procedure produces satisfactory lateral load–displacement relationships, which are comparable with experimental data. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
990.
Richard M. Smith 《The Professional geographer》1986,38(1):62-67
The most common goal when classing data for choropleth maps is to create homogeneous classes which contain similar data values. None of the four traditional data classing methods examined here (quartile, equal interval, standard deviation, and natural breaks) consistently generalized the experimental data sets into homogeneous classes. These methods were most accurate for data sets with specific distributional characteristics, but none classed all of any type of distribution accurately. Only the optimization method produced reliable and accurate results for all of the experimental data. 相似文献