全文获取类型
收费全文 | 188篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 9篇 |
大气科学 | 14篇 |
地球物理 | 53篇 |
地质学 | 73篇 |
海洋学 | 17篇 |
天文学 | 15篇 |
自然地理 | 14篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2018年 | 10篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 12篇 |
2014年 | 7篇 |
2013年 | 9篇 |
2012年 | 8篇 |
2011年 | 13篇 |
2010年 | 14篇 |
2009年 | 16篇 |
2008年 | 12篇 |
2007年 | 7篇 |
2006年 | 9篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有195条查询结果,搜索用时 906 毫秒
101.
Monika B. Kalinowska Paweł M. Rowiński Janusz Kubrak Dorota Mirosław-Świątek 《Acta Geophysica》2012,60(1):214-231
The problem of two-dimensional mathematical modelling of heated cooling water discharges into running waters is considered
in the paper. Two models — one for the evaluation of 2D turbulent velocity field and the other, developed by authors of the
study, for 2D heat transport in open-channels — were used in the calculations. Relevant scenarios of the spread of heated
water discharged from a designed gas-stem power plant to be constructed at the Vistula River were presented. Environmentally
most friendly variant of the discharge of the thermal pollution was selected from among four various variants. 相似文献
102.
Monika Breitzke Olaf Boebel Saad El Naggar Wilfried Jokat Berthold Werner 《Geophysical Journal International》2008,174(2):505-524
Air guns and air-gun arrays of different volumes are used for scientific seismic surveys with R/V Polarstern in polar regions. To assess the potential risk of these research activities on marine mammal populations, knowledge of the sound pressure field of the seismic sources is essential. Therefore, a broad-band (0–80 kHz) calibration study was conducted at the Heggernes Acoustic Range, Norway. A GI (2.4 l), a G (8.5 l) and a Bolt gun (32.8 l) were deployed as single sources, 3 GI (7.4 l), 3 G (25.6 l) and 8 VLF™ Prakla-Seismos air guns (24.0 l) as arrays. Each configuration was fired along a line of 3–4 km length running between two hydrophone chains with receivers in 35, 100, 198 and 263 m depth. Peak-to-peak, zero-to-peak, rms and sound exposure levels (SEL) were analysed as functions of range. They show the typical dipole-like directivity of marine seismic sources with amplitude cancellation close to the sea surface, higher amplitudes in greater depths, and sound pressure levels which continuously decrease with range. Levels recorded during the approach are lower than during the departure indicating a shadowing effect of Polarsterns's hull. Backcalculated zero-to-peak source levels range from 224–240 dB re 1 μPa @ 1 m. Spectral source levels are highest below 100 Hz and amount to 182–194 dB re 1 μPa Hz–1 . They drop off continuously with range and frequency. At 1 kHz they are ∼30 dB, at 80 kHz ∼60 dB lower than the peak level. Above 1 kHz amplitude spectra are dominated by Polarstern's self-noise. From the rms and sound exposure levels of the deepest hydrophone radii for different thresholds are derived. For a 180 dB rms-level threshold radii maximally vary between 200 and 600 m, for a 186 dB SEL threshold between 50 and 300 m. 相似文献
103.
Rüdiger Glaser Dirk Riemann Johannes Schönbein Mariano Barriendos Rudolf Brázdil Chiara Bertolin Dario Camuffo Mathias Deutsch Petr Dobrovolný Aryan van Engelen Silvia Enzi Monika Halíčková Sebastian J. Koenig Oldřich Kotyza Danuta Limanówka Jarmila Macková Mirca Sghedoni Brice Martin Iso Himmelsbach 《Climatic change》2010,101(1-2):235-256
The paper presents a qualitative and quantitative analysis of flood variability and forcing of major European rivers since AD 1500. We compile and investigate flood reconstructions which are based on documentary evidence for twelve Central European rivers and for eight Mediterranean rivers. Flood variability and underlying climatological causes are reconstructed by using hermeneutic approaches including critical source analysis and by applying a semi-quantitative classification scheme. The paper describes the driving climatic causes, seasonality and variability of observed flood events within the different river catchments covering the European mainland. Historical flood data are presented and recent research in the field of historical flood reconstructions is highlighted. Additionally, the character of the different flood series is discussed. A comparison of the historical flood seasonality in relation to modern distribution is given and aspects of the spatial coherence are presented. The comparative analysis points to the fact that the number of flood events is predominately triggered by regional climatic forcing, with at most only minor influence on neighbouring catchments. The only exceptions are extreme, supra-regional climatic events and conditions such as anomalous cold winters, similar to that of 1784, which affected large parts of Europe and triggered flood events in several catchments as a result of ice-break at the beginning of the annual thaw. Four periods of increased occurrence of flooding, mostly affecting Central European Rivers, have been identified; 1540–1600, 1640–1700, 1730–1790, 1790–1840. The reconstruction, compilation and analysis of European-wide flood data over the last five centuries reveal the complexity of the underlying climatological causes and the high variability of flood events in temporal and spatial dimension. 相似文献
104.
Temperature and precipitation fluctuations in the Czech Republic during the period of instrumental measurements 总被引:2,自引:0,他引:2
Rudolf Brázdil Pavel Zahradní?ek Petr Pi?oft Petr ?těpánek Monika Bělínová Petr Dobrovolny 《Theoretical and Applied Climatology》2012,110(1-2):17-34
The history of early meteorological observations using instruments in the Czech Lands is described (the longest temperature series for Prague-Klementinum starts in 1775, precipitation series for Brno in 1803). Using the PRODIGE method, long-term monthly temperature and precipitation series from selected secular stations were homogenised (for 10 and 12 stations, respectively). All the seasonal and annual temperature series for the common period 1882–2010 show a significant positive linear trend with accelerated warming from the 1970s onwards. No significant linear trends were disclosed in the series of seasonal and annual precipitation totals. Correlation coefficients between the Czech series analysed decrease as distances between measuring stations increase. A sharper decrease of correlations for precipitation totals displays much weaker spatial relationships than those for mean temperatures. The highest correlations between all stations appeared in 1921–1950, the lowest in 1891–1920 (temperature) and 1981–2010 (precipitation). Wavelet analysis reveals that very distinct annual cycles as well as the slightly weaker semi-annual ones are better expressed for temperature series than for precipitation. Statistically significant cycles longer than 1?year are temporally unstable and sporadic for precipitation, while in the temperature series cycles of 7.4–7.7 and 17.9–18.4?years were recorded as significant by all stations in 1882–2010 (quasi-biennial cycle of 2.1–2.2?years for half the stations). Czech homogenous temperature series correlate best with those of the Northern Hemisphere for annual, spring and summer values (with significant correlation coefficients between 0.60 and 0.70), but this relation is temporally unstable. Circulation indices, such as the North Atlantic Oscillation Index (NAOI) and the Central European Zonal Index (CEZI), may explain the greater part of Czech temperature variability, especially from December to March and for the winter; however, this relationship is much weaker, or even random, for precipitation series. Further, relationships with the Southern Oscillation Index (SOI) are weak and random. Relatively weak coincidences exist between statistically significant cycles in the Czech series and those detected in NAOI, CEZI and SOI series. 相似文献
105.
106.
107.
Monika E. Huch 《International Journal of Earth Sciences》1988,77(3):777-786
The European Geotraverse (EGT) crosses along a 4000 km profile from the North Cape to Tunisia the following main suture zones: the Tornquist-Teisseyre zone between the Baltic Shield and the Variscan realm, the transition zones between Rhenohercynian and Saxothuringian as well as between Saxothuringian and Moldanubian zones in the Variscan part of central Europe, and the collision zone between the European continent and the Adriatic microplate. Some structural aspects of these suture zones are described. 相似文献
108.
Clémentine Perstrimaux Séverine Le Faucheur Monika Mortimer Serge Stoll Fabrizio Bernardi Aubry Margherita Botter Roberto Zonta Vera I. Slaveykova 《Aquatic Geochemistry》2015,21(2-4):343-362
The present study explores the effect of salinity and dissolved organic carbon (DOC) gradients on the stability and reactivity of titanium dioxide nanoparticle (TiO2-NP) agglomerates in ambient water from the Lagoon of Venice and their possible effect on nauplii sampled at the same locations. In all ambient water samples, TiO2-NPs formed rapidly micrometre-sized agglomerates. The increase in the salinity and concomitant decrease in DOC content induced the formation of larger agglomerates, with z-average hydrodynamic diameter increasing with TiO2-NP concentration and exposure duration. Under the studied conditions, ζ-potential exhibited negative values. In line with agglomeration results, enhancement of the salinity and lower DOC resulted in less negative ζ-potential with close to 0 values in the dispersions of 100 mg L?1 TiO2-NPs in sea water. Two-hour exposure to micrometre-sized agglomerates of TiO2-NPs resulted in an increase in the fluorescence of propidium iodide (PI) stained nauplii in comparison with unexposed controls, but had no effect at 24-h exposure. The increase in nauplii-associated PI fluorescence was more noticeable in dispersions containing 100 mg L?1 than those containing 10 mg L?1 TiO2-NPs, suggesting membrane permeability alteration in a concentration-dependent manner. However, the PI staining results have to be interpreted with caution because of the possible dye binding to the nauplii surface without penetration of cellular membrane. The effect of TiO2-NPs on nauplii was more pronounced at higher salinity and decreased with increasing DOC concentrations at 2 h, while no trends were found at 24-h exposure, as well as exposure to 100 mg L?1 TiO2-NPs. 相似文献
109.
Natural Hazards - The 2016 Kumamoto earthquake (MJMA7.3) struck central area of Kyushu Island, Japan. The presence of near surface low velocity layer greatly amplified the ground motions and caused... 相似文献
110.
Determination of volatile concentrations in fluorapatite of Martian shergottite NWA 2975 by combining synchrotron FTIR,Raman spectroscopy,EMPA, and TEM,and inferences on the volatile budget of the apatite host‐magma 下载免费PDF全文
Ewa Słaby Monika Koch‐Müller Hans‐Jürgen Förster Richard Wirth Dieter Rhede Anja Schreiber Ulrich Schade 《Meteoritics & planetary science》2016,51(2):390-406
We combined the focused ion beam sample preparation technique with polarized synchrotron‐based FTIR (Fourier transform infrared) spectroscopy, laser‐Raman spectroscopy, electron microprobe analysis (EMPA), and transmission electron microscope (TEM) analysis to identify and quantify structurally bound OH, F, Cl, and CO3 groups in fluorapatite from the Northwest Africa 2975 (NWA 2975) shergottite. In this study, the first FTIR spectra of the OH‐stretching region from a Martian apatite are presented that show characteristic OH‐bands of a F‐rich, hydroxyl‐bearing apatite. Depending on the method of apatite‐formula calculation and whether charge balance is assumed or not, the FTIR‐based quantification of the incorporated OH, expressed as wt% H2O, is in variably good agreement with the H2O concentration calculated from electron microprobe data. EMP analyses yielded between 0.35 and 0.54 wt% H2O, and IR data yielded an average H2O content of 0.31 ± 0.03 wt%, consistent with the lower range determined from EMP analyses. The TEM observations implied that the volatiles budget of fluorapatite is magmatic. The water content and the relative volatile ratios calculated for the NWA 2975 magma are similar to those established for other enriched or intermediate shergottites. It is difficult to define the source of enrichment: either Martian wet mantle or crustal assimilation. Comparing the environment of parental magma generation for NWA 2975 with the terrestrial mantle in terms of water content, it displays a composition intermediate between enriched and depleted MORB. 相似文献