全文获取类型
收费全文 | 400篇 |
免费 | 15篇 |
国内免费 | 17篇 |
专业分类
测绘学 | 6篇 |
大气科学 | 40篇 |
地球物理 | 118篇 |
地质学 | 155篇 |
海洋学 | 42篇 |
天文学 | 48篇 |
综合类 | 4篇 |
自然地理 | 19篇 |
出版年
2022年 | 5篇 |
2021年 | 10篇 |
2020年 | 10篇 |
2019年 | 8篇 |
2018年 | 18篇 |
2017年 | 12篇 |
2016年 | 24篇 |
2015年 | 11篇 |
2014年 | 20篇 |
2013年 | 22篇 |
2012年 | 20篇 |
2011年 | 19篇 |
2010年 | 23篇 |
2009年 | 25篇 |
2008年 | 22篇 |
2007年 | 23篇 |
2006年 | 13篇 |
2005年 | 17篇 |
2004年 | 18篇 |
2003年 | 14篇 |
2002年 | 19篇 |
2001年 | 12篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1985年 | 2篇 |
1982年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1973年 | 2篇 |
1964年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有432条查询结果,搜索用时 125 毫秒
221.
222.
Large-scale advective transport through highly heterogeneous 3D formations is investigated using highly resolved numerical simulations and simple analytic models. Investigations are focused on impacts of two types of contaminant injection on transport through isotropic formations where flow conditions are uniform in the average. Transport is quantified by analyzing breakthrough curves for control planes at various distances from the injection zone. In flux-proportional injection mode local mass in injection zone is proportional to local groundwater flux; this setup models many practical cases such as contaminant injection through wells. In resident concentration mode local concentration in injection zone is constant. Results show that impacts of injection mode on breakthrough curves and their moments are strong and they persist for hundreds of correlation scales. The resident concentration mode leads to a fatter tails of the breakthrough curves, while the peaks are generally underpredicted. For a synthetic porous medium with logconductivity variance of 8, dispersivity computed using resident concentration mode at control plane 100 integral scales away from the injection zone was about 10 times larger than corresponding one for flux-proportional mode. Hence, injection mode impacts on transport through highly heterogeneous formations are strong and they persist for large distances from the injection zone. 相似文献
223.
224.
225.
The fracture-induced oscillations in sea ice were detected by seismographs and seismic tiltmeters established on the Arctic
ice pack. Field observations were supplemented with a laboratory experiment. The energy distributions in elastic waves generated
during: (i) large-scale ice pack fragmentation over area of about 105 km2, (ii) local crack propagation in ice floe, and (iii) laboratory ice crashing were constructed and analyzed using principles
of the Tsallis statistics. The energy release regimes at different stages of fracturing were characterized by the parameter
of nonextensivity q. In terms of the non-extensive statistical mechanics, q > 1 evidences the correlated (non-extensive) dynamics of the process in nonequilibrium system, q = 1 responds to the additivity of events occurring in equilibrium system, and q < 1 takes place when the energy release is additive and limited by an upper cut-off. All these scenarios were revealed in
fracture processes occurring at three hierarchic levels. The variation of the q-value demonstrates high thermodynamic changeability of the fracture process driven by irregular external source. The role
of energy conservation in fracturing sea ice is discussed in connection with the observed reversible transitions between extensive
and non-extensive modes of fracture. 相似文献
226.
227.
Vadim Vasilevich Novotryasov Dmitry Vadimovich Stepanov Igor Olegovich Yaroshchuk 《Ocean Dynamics》2016,66(1):19-25
Observations are presented of internal undular bores (IUBs) on the Japan/East Sea coast. We found three types of IUB amplitude modulation functions. The first type (IUB1) has a leading edge, which is formed by the soliton with maximal amplitude. The second type (IUB2) has a soliton with maximal amplitude (SMA) located between the leading and trailing edges. The third type (IUB3) consists of 2–3 solitons, which have identical amplitudes. The evolution of the IUB2 from the moment of generation to the moment of maximal development was analyzed. The speed of the IUB2 approached to the phase speed of linear internal waves with a period of 12.4 h. The amplitude modulation function of the IUB2 is believed to be unique in ocean observations. Observations are discussed in the context of recently raised hypotheses concerning the evolution of IUBs in the coastal environment. 相似文献
228.
Alexey V. Eliseev Alexandr V. Chernokulsky Andrey A. Karpenko Igor I. Mokhov 《Theoretical and Applied Climatology》2010,101(1-2):67-81
An approach to mitigate global warming via sulphur loading in the stratosphere (geoengineering) is studied, employing a large ensemble of numerical experiments with the climate model of intermediate complexity IAP RAS CM. The model is forced by the historical+SRES A1B anthropogenic greenhouse gases+tropospheric sulphates scenario for 1860–2100 with additional sulphur emissions in the stratosphere in the twenty-first century. Different ensemble members are constructed by varying values of the parameters governing mass, horizontal distribution and radiative forcing of the stratospheric sulphates. It is obtained that, given a global loading of the sulphates in the stratosphere, among those studied in this paper latitudinal distributions of geoengineering aerosols, the most efficient one at the global basis is that peaked between 50°N and 70°N and with a somewhat smaller burden in the tropics. Uniform latitudinal distribution of stratospheric sulphates is a little less efficient. Sulphur emissions in the stratosphere required to stop the global temperature at the level corresponding to the mean value for 2000–2010 amount to more than 10 TgS/year in the year 2100. These emissions may be reduced if some warming is allowed to occur in the twenty-first century. For instance, if the global temperature trend S g in every decade of this century is limited not to exceed 0.10 K/decade (0.15 K/decade), geoengineering emissions of 4–14 TgS/year (2–7 TgS/year) would be sufficient. Even if the global warming is stopped, temperature changes in different regions still occur with a magnitude up to 1 K. Their horizontal pattern depends on implied latitudinal distribution of stratospheric sulphates. In addition, for the stabilised global mean surface air temperature, global precipitation decreases by about 10%. If geoengineering emissions are stopped after several decades of implementation, their climatic effect is removed within a few decades. In this period, surface air temperature may grow with a rate of several Kelvins per decade. The results obtained with the IAP RAS CM are further interpreted employing a globally averaged energy–balance climate model. With the latter model, an analytical estimate for sulphate aerosol emissions in the stratosphere required climate mitigation is obtained. It is shown that effective vertical localisation of the imposed radiative forcing is important for geoengineering efficiency. 相似文献
229.
Sensitivity of simulated wintertime Arctic atmosphere to vertical resolution in the ARPEGE/IFS model
The current state-of-the-art general circulation models, including several of those used by the IPCC, show considerable biases
in the simulated present day high-latitude climate compared to observations and reanalysis data. These biases are most pronounced
during the winter season. We here employ ideal vertical profiles of temperature and wind from turbulence-resolving simulations
to perform a priori studies of the first-order eddy-viscosity closure scheme employed in the ARPEGE/IFS model. This reveals
that the coarse vertical resolution (31 layers) of the model cannot be expected to realistically resolve the Arctic stable
boundary layer. The curvature of the Arctic inversion and thus also the vertical turbulent-exchange processes cannot be reproduced
by the coarse vertical mesh employed. To investigate how turbulent vertical exchange processes in the Arctic boundary layer
are represented by the model parameterization, a simulation with high vertical resolution (90 layers in total) in the lower
troposphere is performed. Results from the model simulations are validated against data from the ERA-40 reanalysis. The dependence
of the surface air temperature on surface winds, surface energy fluxes, free atmosphere stability and boundary layer height
is investigated. The coarse-resolution run reveals considerable biases in these parameters, and in their physical relations
to surface air temperature. In the simulation with fine vertical resolution, these biases are clearly reduced. The physical
relation between governing parameters for the vertical turbulent-exchange processes improves in comparison with ERA-40 data. 相似文献
230.
Igor M. Logvinov 《Acta Geophysica》2015,63(5):1216-1230
The results of deep induction sounding in Ukraine made in the twenty-first century with the participation of the author have been summarized, including also a number of data obtained in the previous decades. The apparent resistivity and magnetic transfer function on the territories of western Ukraine and eastern Poland have been analyzed. The articulation of these data with the regional magnetic variation soundings allowed taking into account the influence of a static shift of areal interpretation of magnetotelluric resistivity results, which increased the reliability of interpretation. The analysis of induction sounding performed with 1D, 2D, and 3D inversions of magnetic transfer functions allowed localizing the crustal anomalies. The results are discussed. 相似文献