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31.
Federico Murrone Fabio Rossi Pierluigi Claps 《Stochastic Environmental Research and Risk Assessment (SERRA)》1997,11(6):483-510
A conceptual-stochastic approach to short time runoff data modelling is proposed, according to the aim of reproducing the
hydrological aspects of the streamflow process and of preserving as much as possible the dynamics of the process itself. This
latter task implies preservation of streamflow characteristics at higher scales of aggregation and, within a conceptual framework,
involves compatibility with models proposed for the runoff process at those scales. At a daily time scale the watershed response
to the effective rainfall is considered as deriving from the response of three linear reservoirs, respectively representing
contributions to streamflows of large deep aquifers, with over-year response lag, of aquifers which run dry by the end of
the dry season and of subsurface runoff. The surface runoff component is regarded as an uncorrelated point process. Considering
the occurrences of effective rainfall events as generated by an independent Poisson process, the output of the linear system
represents a conceptually-based multiple shot noise process. Model identification and parameter estimation are supported by
information related to the aggregated runoff process, in agreement to the conceptual framework proposed, and this allows parameter
parsimony, efficient estimation and effectiveness of the streamflow reproduction. Good performances emerged from the model
application and testing made with reference to some daily runoff series from Italian basins. 相似文献
32.
33.
European Geostationary Navigation Overlay Service (EGNOS) is a satellite-based system developed to improve the performance
of GPS in the European region. It not only enhances the estimated positioning accuracy but also provides an integrity solution.
We assess the EGNOS performance through analysis of real measurements, performed in different road user environments. We investigate
the use of the integrity concept in future Global Navigation Satellite System (GNSS)-based applications in the road environment,
considering both suburban and dense urban areas. The analysis is motivated by the fact that there is an increasing number
of road applications, such as billing system, transportation of dangerous goods, remote tracking of trucks and snow plows,
fleet management and “pay as you go” car insurances, where the system liability has to be guaranteed. The scope of the analysis
is to investigate to which extent the use of the integrity concept can be used for such purpose; the assessment is based on
real measurement campaigns in representative environments, providing statistical results in terms of accuracy and integrity,
and in a wider sense of the feasibility of the use of EGNOS for augmenting the reliability of GNSS positioning for road applications. 相似文献
34.
35.
Jesús López H. Fabio Bresolin Elena Terlevich Roberto Terlevich Daniel Rosa-González 《Astrophysics and Space Science》2009,324(2-4):351-354
We present preliminary results obtained from integral-field (IFU) data of the giant extragalactic Hii region NGC5461, located in a spiral arm (RA=14h03m41.4s, dec=+54°19′05″) of M101. The spatial and spectral information obtained with IFUs allows us to decompose the Hii region and analyze it at high resolution. 相似文献
36.
Phase transitions taking place during the inflationary epoch give rise to bubbles of true vacuum embedded in the false vacuum. These bubbles can imprint a distinctive signal on the Cosmic Microwave Background (CMB). We evaluate the feasibility of detecting these signatures with wavelets in CMB maps, such as those that will be made available by the European Space Agency’s (ESA) Planck mission. 相似文献
37.
A TRACE field of view well inside the solar disk shows very well defined large loops, likely to be very inclined to the solar
surface. On the other hand there is little evidence of large loops perpendicular to the solar surface. We show that this does
not mean that most large loops have such large inclination but that perpendicular loops are much less visible to TRACE, because
of density stratification. We quantitatively evaluate this effect by modeling in detail loops with different inclinations. 相似文献
38.
Midlittoral polychaete communities in the Eastern Mediterranean Sea: new information from the implementation of the Natural Geography in Shore Areas (NaGISA) protocol and comparisons at local and regional scales 下载免费PDF全文
Georgios Chatzigeorgiou Kleoniki Keklikoglou Sarah Faulwetter Fabio Badalamenti Miltiadis‐Spyridon Kitsos Christos Arvanitidis 《Marine Ecology》2017,38(1)
The aim of this study was to attempt to fill current knowledge gaps on midlittoral Mediterranean biodiversity at local and regional scales, by using benthic polychaetes as a model taxon. Two different data sets were analysed: (i) a quantitative data set from the two Natural Geography in Shore Areas (NaGISA) study sites in Crete and (ii) a qualitative data set from multiple sites across the Mediterranean. At the local scale, the results provide evidence that (i) discrete species communities are formed in midlittoral Mediterranean habitats, which vary by geographical location and year, depending on the scale of observation; (ii) macrophyte coverage and Chl‐a are the only environmental variables associated, albeit weakly, with the above pattern; (iii) although naturally disturbed, the Cretan NaGISA sites do not seem to experience any anthropogenic stress; (iv) environmental heterogeneity and history seem to be much less important in shaping the polychaete communities than inter‐specific interactions; however, it is not possible to specify at this stage whether local or regional processes or even their interactions may shape the polychaete communities. At the regional scale, the results indicate that (i) the only factor that seems to be involved in the regional pattern is the identity of the study providing the data sets, which implies variability and bias in how research projects are carried out, from the sampling design through to data collection and analysis; (ii) the Cretan NaGISA sites may be considered as representative of the habitat in the Mediterranean, under certain conditions. 相似文献
39.
Rockfall risk assessment to persons travelling in vehicles along a road: the case study of the Amalfi coastal road (southern Italy) 总被引:2,自引:0,他引:2
The paper deals with the assessment of rockfall risk to persons travelling in vehicles along the SS163 road, an important transportation corridor supporting a high vehicle traffic within the well-known tourist area of the Amalfi Coast (southern Italy). To this aim, the Rockfall Hazard Rating System (RHRS) and quantitative risk assessment (QRA) procedures, in this latter case for three rockfall risk scenarios, are applied. With reference to a large portion (33.820 out of a total of 50.365 km) of the SS163 road, the obtained QRA results highlight that, although the estimated individual risk to life satisfies the adopted tolerable risk criterion, the computed societal risk cannot be tolerated. Starting from this result, site-specific QRA analyses—carried out with reference to some road sections chosen on the basis of the RHRS results—allow the detection of the SS163 portions where the individual risk to life exceeds the tolerable risk threshold and, then, the recourse to mitigation measures could reveal necessary. In this regard, RHRS and QRA methods can be considered complementary tools in prioritizing the road sections where construction funds can be profitably spent in order to mitigate the rockfall risk with reference to both direct consequences (life loss) and indirect ones (traffic delay and diversions). 相似文献
40.
Tobias Dürig Fabio Dioguardi Ralf Büttner Pierfrancesco Dellino Daniela Mele Bernd Zimanowski 《Bulletin of Volcanology》2012,74(4):895-902
Brittle magmatic fragmentation plays a crucial role in explosive eruptions. It represents the starting point of hazardous
explosive events that can affect large areas surrounding erupting volcanoes. Knowing the initial energy released during this
fragmentation process is fundamental for the understanding of the subsequent dynamics of the eruptive gas-particle mixture
and consequently for the forecasting of the erupting column’s behavior. The specific kinetic energy (SKE) of the particles
quantifies the initial velocity shortly after the fragmentation and is therefore a necessary variable to model the gas-particle
conduit flow and eruptive column regime. In this paper, we present a new method for its determination based on fragmentation
experiments and identification of the timings of energy release. The results obtained on compositions representative for basaltic
and phonolitic melts show a direct dependence on magma material properties: poorly vesiculated basaltic melts from Stromboli
show the highest SKE values ranging from 7.3 to 11.8 kJ/kg, while experiments with highly vesiculated samples from Stromboli
and Vesuvius result in lower SKE values (3.1 to 3.8 kJ/kg). The described methodology presents a useful tool for quantitative
estimation of the kinetic energy release of magmatic fragmentation processes, which can contribute to the improvement of hazard
assessment. 相似文献