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241.
In 2009, Sweden experienced a wave of urban unrest concentrated in areas with large foreign-born populations. This episode was seen by many as reflecting a trend towards increased ethnically based residential segregation, in line with scholarly literatures that correlate inequality and rising segregation with increases in unrest or rebellion. In this paper, we analyze the empirical connection between ethnic residential segregation and episodes of urban unrest in Sweden. Unrest is measured by the number of car burnings reported to police between 2002 and 2009. We find a positive and statistically significant link between residential segregation and car burnings at the scale of municipalities and metropolitan districts. Unrest/rebellion is also correlated with high proportion of young adults and social welfare assistance. 相似文献
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243.
Elmar BUCHNER Martin SCHMIEDER Gero KURAT Franz BRANDSTÄTTER Utz KRAMAR Theo NTAFLOS Jörg KRÖCHERT 《Meteoritics & planetary science》2012,47(9):1491-1501
Abstract– The fall of meteorites has been interpreted as divine messages by multitudinous cultures since prehistoric times, and meteorites are still adored as heavenly bodies. Stony meteorites were used to carve birds and other works of art; jewelry and knifes were produced of meteoritic iron for instance by the Inuit society. We here present an approximately 10.6 kg Buddhist sculpture (the “iron man”) made of an iron meteorite, which represents a particularity in religious art and meteorite science. The specific contents of the crucial main (Fe, Ni, Co) and trace (Cr, Ga, Ge) elements indicate an ataxitic iron meteorite with high Ni contents (approximately 16 wt%) and Co (approximately 0.6 wt%) that was used to produce the artifact. In addition, the platinum group elements (PGEs), as well as the internal PGE ratios, exhibit a meteoritic signature. The geochemical data of the meteorite generally match the element values known from fragments of the Chinga ataxite (ungrouped iron) meteorite strewn field discovered in 1913. The provenance of the meteorite as well as of the piece of art strongly points to the border region of eastern Siberia and Mongolia, accordingly. The sculpture possibly portrays the Buddhist god Vai?ravana and might originate in the Bon culture of the eleventh century. However, the ethnological and art historical details of the “iron man” sculpture, as well as the timing of the sculpturing, currently remain speculative. 相似文献
244.
In this study, we present the first Johnson BV photometry of the eclipsing binary star ET Bootis, which is member of a physically connected visual pair. Analysis of times of light minima enables us to calculate accurate ephemeris of the system via O–C analysis and observed an increase in period which we believe is a result of the light-time effect in the outer visual orbit. Secondly, we determined the total brightness and color of the system in light maxima and minima. Photometric solution of the system indicates that the contribution of the visual pair to the total light is about 40% in Johnson V band. Furthermore, photometric analysis shows that the primary star in the eclipsing binary has F8 spectral type while it confirms the G5 spectral type for the visual pair. Masses of the components in eclipsing binary are M1 = 1.109 ± 0.014 M⊙ and M2 = 1.153 ± 0.011 M⊙. Absolute radii of the components are R1 = 1.444 ± 0.007 R⊙ and R2 = 1.153 ± 0.007 R⊙. Physical properties of the components leads 176 ± 7 pc distance for the system and suggests an age of 6.5 billion years. 相似文献
245.
Bodrum Peninsula is located between Hellenic Trench in the west and Gökova Fault Zone in the east which is affected by hundreds of earthquakes every year. Because of its active environment is allowed to monitor tracers/precursors continuously to analyse natural processes. This study focused on the determination of ground water radon (222Rn) concentrations in the Bodrum Peninsula in terms of seismic activities. Radon levels of ten ground water wells were measured periodically throughout the peninsula and these wells were divided into two groups according to the number of earthquakes they are exposed. Radon variations in second group stations are fairly significant as a result of high number of earthquakes. In these stations, radon continuously increased before the seismic storm and then decreased step by step. The results indicated that radon variations in ground waters of Bodrum Peninsula can be a good indicator for seismic storms instead of one specific event. 相似文献
246.
Application of linear stochastic models for drought forecasting in the Büyük Menderes river basin, western Turkey 总被引:6,自引:3,他引:3
Ömer Faruk Durdu 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(8):1145-1162
In the present study, a seasonal and non-seasonal prediction of the Standardized Precipitation Index (SPI) time series is
addressed by means of linear stochastic models. The methodology presented here is to develop adequate linear stochastic models
known as autoregressive integrated moving average (ARIMA) and multiplicative seasonal autoregressive integrated moving average
(SARIMA) to predict drought in the Büyük Menderes river basin using SPI as drought index. Temporal characteristics of droughts
based on SPI as an indicator of drought severity indicate that the basin is affected by severe and more or less prolonged
periods of drought from 1975 to 2006. Therefore, drought prediction plays an important role for water resources management.
ARIMA modeling approach involves the following three steps: model identification, parameter estimation, diagnostic checking.
In model identification step, considering the autocorrelation function (ACF) and partial autocorrelation function (PACF) results
of the SPI series, different ARIMA models are identified. The model gives the minimum Akaike Information Criterion (AIC) and
Schwarz Bayesian Criterion (SBC) is selected as the best fit model. Parameter estimation step indicates that the estimated
model parameters are significantly different from zero. Diagnostic check step is applied to the residuals of the selected
ARIMA models and the results indicated that the residuals are independent, normally distributed and homoscedastic. For the
model validation purposes, the predicted results using the best ARIMA models are compared to the observed data. The predicted
data show reasonably good agreement with the actual data. The ARIMA models developed to predict drought found to give acceptable
results up to 2 months ahead. The stochastic models developed for the Büyük Menderes river basin can be employed to predict
droughts up to 2 months of lead time with reasonably accuracy. 相似文献
247.
248.
Bilge Özbay 《洁净——土壤、空气、水》2012,40(6):571-577
Air quality has been deteriorated seriously in urban areas as a result of increasing anthropogenic activities. Meteorological conditions affect air pollution levels in the urban atmosphere significantly due to their important role in transport and dilution of the pollutants. This paper aims to investigate usability of some promising statistical methods for examining the impacts of metrological factors on SO2 and PM10 levels. Data were collected from city centre of Kocaeli in winter periods from 2007 to 2010 as pollutant concentrations increase in winters due to expanding combustion facilities. Results of bivariate correlation analysis showed that humidity and rainfall have remarkable negative correlations with the pollutants. Multiple linear regression models and artificial neural network (ANN) models were used to predict next day's PM10 and SO2 levels. In regression models calculated R2 values were 0.89 and 0.75 for PM10 and SO2, respectively. Among the various architectures, single layer networks provided better performance in ANN applications. Highest R2 values were obtained as 0.89 and 0.69 for PM10 and SO2, respectively, by using appropriate networks. 相似文献
249.
This study aims to remove of Cu2+, Cd2+, and Pb2+ ions from solution and to investigate the adsorption isotherms, adsorption kinetics, and ion‐exchange affinities of these metals using waste activated sludge (AS) biomass. The adsorptions of the metals on biomass were optimal at an acidic pH value of 6.0 based on its monolayer capacities. Maximum monolayer capacities of AS biomass (qmax) were calculated as 0.478, 0.358, and 0.280 mmol g?1 for Cu2+, Cd2+, and Pb2+, respectively, and the adsorption equilibrium time was found as 60 min for each metal. The adsorbed amount of metal rose with increasing of initial metal ion concentration. The equilibrium adsorption capacity of AS for initial 0.25 mmol L?1 metal concentration was determined as 0.200, 0.167, and 0.155 mmol g?1 for Cu2+, Cd2+, and Pb2+ ions, respectively. These relevant values were determined as 0.420, 0.305, and 0.282 mmol g?1 for Cu2+, Cd2+, and Pb2+ ions, respectively, when initial metal concentration was 0.50 mmol L?1. In the multi‐metal sorption system, the adsorption capacity of AS biomass was observed in the order of Cu2+ > Cd2+ > Pb2+. In the presence of 100 mmol L?1 H+ ion, the order of ion‐exchange affinity with H+ was found as Cu2+ > Cd2+ > Pb2+. The adsorption kinetics were also found to be well described by the pseudo‐second‐order and intraparticle diffusion models. Two different rate constants were obtained as ki1 and ki2 and ki1 (first stage) was found to be higher than ki2 (second stage). 相似文献
250.
Abstract— We present laboratory mid‐infrared absorption spectra (2.5 urn to 16.0 μm) of powdered calcium‐aluminum‐rich inclusions (CAIs) and matrix separated from the carbonaceous chondrites Allende (CV3.2), Vigarano (CV3.3), and Ornans (C03.3). Two groups of spectra with different features were found for the CAI: in the first group spectra are dominated by spinel, pyroxene, and sodalite ± nepheline, where main features occur at 9.3 μm, 10.3 μm, and 11.3 μm. In the second group, characteristic minerals are spinel and melilite with typical band maxima at 11.0 μm and 12.3 μm, and a broad feature between 14.0 μn and 15.0 μn. The position of the broad spinel feature probably depends on its iron content. Comparison of band positions in spectra from the CAI components to observed circumstellar emission spectra indicates the potential occurrence of CAI‐like material. Pyroxene‐ and spinel‐rich features could occur in spectra of dust around the Herbig Ae star HD104237, the T Tauri star Hen3‐600 and the post‐AGB star R Sge. Melilite‐ and spinel‐rich components possibly appear in the spectrum of HD 104237, Hen3‐600, 04187_1927, R Sge, and the planetary nebula Hb 12. There is also indication for a spinel component in dust from the Herbig Ae/Be star HD 179218. The spectra of the AGB stars R Cas and θ Aps show no features of CAl‐type spinel. 相似文献