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101.
Relative sea level rise (RSLR) due to climate change and geodynamics represents the main threat for the survival of Venice,
emerging today only 90 cm above the Northern Adriatic mean sea level (msl). The 25 cm RSLR occurred over the 20th century,
consisting of about 12 cm of land subsidence and 13 cm of sea level rise, has increased the flood frequency by more than seven
times with severe damages to the urban heritage. Reasonable forecasts of the RSLR expected to the century end must be investigated
to assess the suitability of the Mo.S.E. project planned for the city safeguarding, i.e., the closure of the lagoon inlets
by mobile barriers. Here we consider three RSLR scenarios as resulting from the past sea level rise recorded in the Northern
Adriatic Sea, the IPCC mid-range A1B scenario, and the expected land subsidence. Available sea level measurements show that
more than 5 decades are required to compute a meaningful eustatic trend, due to pseudo-cyclic 7–8 year long fluctuations.
The period from 1890 to 2007 is characterized by an average rate of 0.12 ± 0.01 cm/year. We demonstrate that linear regression
is the most suitable model to represent the eustatic process over these 117 year. Concerning subsidence, at present Venice
is sinking due to natural causes at 0.05 cm/year. The RSLR is expected to range between 17 and 53 cm by 2100, and its repercussions
in terms of flooding frequency are associated here to each scenario. In particular, the frequency of tides higher than 110 cm,
i.e., the value above which the gates would close the lagoon to the sea, will increase from the nowadays 4 times per year
to a range between 20 and 250. These projections provide a large spread of possible conditions concerning the survival of
Venice, from a moderate nuisance to an intolerable aggression. Hence, complementary solutions to Mo.S.E. may well be investigated. 相似文献
102.
Diana Rodriguez Ana Rodriguez Amparo Soto Alfonso Aranda Yolanda Diaz-de-Mera Alberto Notario 《Journal of Atmospheric Chemistry》2008,59(3):187-197
The reactions of three structurally similar unsaturated alcohols, 2-buten-1-ol (crotyl alcohol), 2-methyl-2-propen-1-ol (MPO221)
and 3-methyl-2-buten-1-ol (MBO321) with Cl atoms, have been investigated for the first time, using a 400 l Teflon reaction
chamber coupled with gas chromatograph-coupled with flame-ionization detection (GC-FID). The experiments were performed at
atmospheric pressure and at temperatures between 255 and 298 K, in air or nitrogen as the bath gas. The obtained kinetic data
were used to derive the Arrhenius expressions , , (in units of cm3 molecule−1 s−1). Finally, atmospheric lifetimes of those unsaturated alcohols with respect to OH, NO3, O3 and Cl have been calculated. 相似文献
103.
On the Derivation of Input Parameters for Urban Canopy Models from Urban Morphological Datasets 总被引:2,自引:1,他引:1
Alberto Martilli 《Boundary-Layer Meteorology》2009,130(2):301-306
Two techniques are analysed to derive mean street width and mean building width from morphological data of real cities: one
based on a two-dimensional simplified morphology, and the other based on a three-dimensional regular simplified morphology.
For each simplified morphology (two-dimensional and three-dimensional), the sky-view factors (street-to-sky) are computed
and compared with the sky-view factors derived from the real morphology for selected districts of three European and two North
American cities. The two-dimensional simplified morphology reproduces the real sky-view factors better than the three-dimensional
morphology. Since many urban canopy parameterizations represent the city using simplified morphologies, this can be useful
information for the derivation of input parameters for urban canopy parameterizations from real morphological data. 相似文献
104.
Pablo Arnalte-Mur Alberto Fernández-Soto Vicent J. Martínez Enn Saar Pekka Heinämäki Ivan Suhhonenko 《Monthly notices of the Royal Astronomical Society》2009,394(3):1631-1639
Measurements of clustering in large-scale imaging surveys that make use of photometric redshifts depend on the uncertainties in the redshift determination. We have used light-cone simulations to show how the deprojection method successfully recovers the real-space correlation function when applied to mock photometric redshift surveys. We study how the errors in the redshift determination affect the quality of the recovered two-point correlation function. Considering the expected errors associated with the planned photometric redshift surveys, we conclude that this method provides information on the clustering of matter useful for the estimation of cosmological parameters that depend on the large-scale distribution of galaxies. 相似文献
105.
Mario Gai Alberto Vecchiato Sebastiano Ligori Alessandro Sozzetti Mario G. Lattanzi 《Experimental Astronomy》2012,34(2):165-180
The Gravitation Astrometric Measurement Experiment (GAME) is a mission concept based on astronomical techniques (astrometry and coronagraphy) for Fundamental Physics measurements, namely the ?? and ?? parameters of the Parametrized Post-Newtonian formulation of gravitation theories extending the General Relativity. The science case also addresses cosmology, extra-solar planets, Solar System objects and fundamental stellar parameters. The mission concept is described, including the measurement approach and the instrument design. 相似文献
106.
Richard A. Frazin Alberto M. Vásquez William T. Thompson Russell J. Hewett Philippe Lamy Antoine Llebaria Angelos Vourlidas Joan Burkepile 《Solar physics》2012,280(1):273-293
In order to assess the reliability and consistency of white-light coronagraph measurements, we report on quantitative comparisons between polarized brightness [pB] and total brightness [B] images taken by the following white-light coronagraphs: LASCO-C2 on SOHO, SECCHI-COR1 and -COR2 on STEREO, and the ground-based MLSO-Mk4. The data for this comparison were taken on 16?April 2007, when both STEREO spacecraft were within 3.1° of Earth??s heliographic longitude, affording essentially the same view of the Sun for all of the instruments. Due to the difficulties of estimating stray-light backgrounds in COR1 and COR2, only Mk4 and C2 produce reliable coronal-hole values (but not at overlapping heights), and these cannot be validated without rocket flights or ground-based eclipse measurements. Generally, the agreement between all of the instruments?? pB values is within the uncertainties in bright streamer structures, implying that measurements of bright CMEs also should be trustworthy. Dominant sources of uncertainty and stray light are discussed, as is the design of future coronagraphs from the perspective of the experiences with these instruments. 相似文献
107.
Josep M. Trigo-Rodriguez José M. Madiedo Peter S. Gural Alberto J. Castro-Tirado Jordi Llorca Juan Fabregat Standa Vítek Pep Pujols 《Earth, Moon, and Planets》2008,102(1-4):231-240
By using high-resolution, low-scan-rate, all-sky CCD cameras, the SPanish Meteor Network (SPMN) is currently monitoring meteor
and fireball activity on a year round basis. Here are presented just a sampling of the accurate trajectory, radiant and orbital
data obtained for meteors imaged simultaneously from two SPMN stations during the continuous 2006–2007 coverage of meteor
and fireball monitoring. Typical astrometric uncertainty is 1–2 arc min, while velocity determination errors are of the order
of 0.1–0.5 km/s, which is dependent on the distance of each event to the station and its particular viewing geometry. The
cameras have demonstrated excellent performance for detecting meteor outbursts. The recent development of automatic detection
software is also providing real-time information on the global meteor activity. Finally, some examples of the all-sky CCD
cameras applications for detecting unexpected meteor activity are given. 相似文献
108.
We have investigated the effects of different Fe2O3 bulk contents on the calculated phase equilibria of low‐T/intermediate‐P metasedimentary rocks. Thermodynamic modelling within the MnO–Na2O–K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–O (MnNKFMASHTO) chemical system of chloritoid‐bearing hematite‐rich metasedimentary rocks from the Variscan basement of the Pisani Mountains (Northern Apennines, Italy) fails to reproduce the observed mineral compositions when the bulk Fe2O3 is determined through titration. The mismatch between observed and computed mineral compositions and assemblage is resolved by tuning the effective ferric iron content by P–XFe2O3 diagrams, obtaining equilibration conditions of 475 °C and 9–10 kbar related to a post‐compressional phase of the Alpine collision. The introduction of ferric iron affects the stability of the main rock‐forming silicates that often yield important thermobaric information. In Fe2O3‐rich compositions, garnet‐ and carpholite‐in curves shift towards higher temperatures with respect to the Fe2O3‐free systems. The presence of a ferric‐iron oxide (hematite) prevents the formation of biotite in the mineral assemblage even at temperatures approaching 550 °C. The use of P–T–XFe2O3 phase diagrams may also provide P–T information in common greenschist facies metasedimentary rocks. 相似文献
109.
Alberto Longo Manuel Pastor Lorenzo Sanavia Diego Manzanal Miguel Martin Stickle Chuan Lin Angel Yague Saeid Moussavi Tayyebi 《国际地质力学数值与分析法杂志》2019,43(5):833-857
Classical depth-integrated smoothed particle hydrodynamics (SPH) models for avalanches are extended in the present work to include a μ(I)− rheological model enriched with a fragmentation law. With this improvement, the basal friction becomes grain distribution dependent. Rock avalanches, where grain distribution tends to change with time while propagating, are the appropriate type of landslide to apply the new numerical proposal. The μ(I)− rheological models considered in the present work are those of Hatano and Gray, combined with two different fragmentation laws, a hyperbolic and a fractal-based law. As an application, Frank avalanche, which took place in Canada in 1903, is analyzed under the scope of the present approach, focusing in the influence of the rheological and fragmentation laws in the evolution of the avalanche. 相似文献
110.
Antonio Luis Montealegre-Gracia María Teresa Lamelas-Gracia Alberto García-Martín Juan de la Riva-Fernández Francisco Escribano-Bernal 《地理信息系统科学与遥感》2017,54(5):721-740
The aim of study is to map the carbon dioxide (CO2) emission of the aboveground tree biomass (AGB) in case of a fire event. The suitability of low point density, discrete, multiple-return, Airborne Laser Scanning (ALS) data and the influence of several characteristics of these data and the study area on the results obtained have been evaluated. A sample of 45 circular plots representative of Pinus halepensis Miller stands were used to fit and validate the model of AGB. The ALS point clouds were processed to obtain the independent variables and a multivariate linear regression analysis between field data and ALS-derived variables allowed estimation of AGB. Then, the influence of several characteristics on the residuals of the model was analyzed. Finally, conversion factors were applied to obtain the CO2 values. The AGB model presented a R2 value of 0.84 with a relative root-mean-square error of 27.35%. This model included ALS variables related to vegetation height variability and to canopy density. Terrain slope, aspect, canopy cover, scan angle and the number of laser returns did not influence AGB estimations at plot level. 相似文献