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101.
Landslide risk: some issues that determine societal acceptance   总被引:2,自引:1,他引:1  
This paper illustrates approaches to landslide risk acceptance in various parts of the world in the context of the willingness to accept that risk, the willingness to pay to reduce the risk, and the willingness to alter the environment in the process. These factors are interlinked using the ternary ??willingness diagram?? which is also used to demonstrate how such willingness may change over time and to compare a range of generic approaches to landslide remediation as well as different conceptual approaches to landslide risk management. The willingness construct is intended to provide a readily understood framework for infrastructure owners and operators, amongst others, to understand how their approach to risk management compares with those in other regions, countries and contexts. Issues relevant to the response of society and groups of individuals to landslide risk, its acceptance and management include cultural factors, regulation and planning, budgetary constraints, vehicular vulnerability, and the often limited size of the event footprint compared to the vulnerability shadow that is cast are also discussed.  相似文献   
102.
Marine and river bedforms are rhythmic features driven by unidirectional or reversing currents and waves. They are ubiquitous on the floors of rivers, estuaries, coastal and marine settings. Despite a considerable history of dedicated studies, many aspects of their origin, development and dynamics are still the subject of scientific debate in various disciplines. The MARID conferences series hosts experts from geosciences, physics, engineering and other disciplines to provide a platform for the interdisciplinary exchange of fundamental and applied knowledge of marine and river dune dynamics. MARID VI took place in April 2019 in Bremen, Germany. Related scientific contributions are presented in this special issue of Earth Surface Processes and Landforms. An overview of the conference series and the specifics of MARID VI, as well as considerations in the context of equity, diversity and inclusion, are given. This introduction highlights the progress made with the papers published in the special issue.  相似文献   
103.
Saturn's F ring has been the subject of study due to its peculiar structure and the proximity to two satellites, named Prometheus (interior) and Pandora (exterior to the ring), which cause perturbations to the ring particles. Early results from Voyager data have proposed that the ring is populated with centimetre- and micrometre-sized particles. The Cassini spacecraft also detected a less dense part in the ring with width of 700 km. Small particles suffer the effects of solar radiation. Burns et al. showed that due to effects of one component of the solar radiation, the Poynting–Robertson drag, a ring particle will decay in the direction of the planet in a time much shorter than the age of the Solar system. In this work, we have analysed a sample of dust particles (1, 3, 5 and 10 μm) under the effects of solar radiation, the Poynting–Robertson drag and the radiation pressure components and the gravitational effects of the satellites Prometheus and Pandora. In this case, the high increase of the eccentricity of the particles leads almost all of them to collide with the outer edge of the A ring. The inclusion of the oblateness of Saturn in this system significantly changes the outcome, since the large variation of the eccentricity is reduced by the oblateness effect. As a result, there is an increase in the lifetime of the particle in the envelope region. Our results show that even the small dust particles, which are very sensitive to the effects of solar radiation, have an orbital evolution similar to larger particles located in the F ring. The fate of all particles is a collision with Prometheus or Pandora in less than 30 years. On the other hand, collisions of these particles with moonlets/clumps present in the F ring could change this scenario.  相似文献   
104.
105.
An ensemble of six 22-year numerical experiments was conducted to evaluate the ability of Regional Climate Model version 3 (RegCM3) to simulate the energy and water budgets of the midwestern United States. RegCM3 was run using two surface physics schemes: Integrated Biosphere Simulator (IBIS) and Biosphere-Atmosphere Transfer Scheme 1e (BATS1e), and two convective closure assumptions: Fritsch & Chappell (FC80) and Arakawa & Schubert (AS74). Boundary conditions were provided by the National Centers for Environmental Prediction-Department of Energy Reanalysis 2 dataset and the ECHAM5 general circulation model. A companion paper examines the American Midwest under future climate scenarios. Overall, the model that reproduces the observed seasonal cycles of the midwestern United States climate system best is RegCM3 using IBIS and the AS74 convective closure assumption. IBIS simulates shortwave radiation more accurately, while BATS1e simulates longwave radiation more accurately. Summer two-meter air temperature is overestimated by the combination of IBIS and the FC80 convective closure assumption. All models contain a wet bias and overestimate evapotranspiration during the spring. Total runoff, surface runoff, groundwater runoff, and root zone soil moisture are best simulated by RegCM3 using IBIS and the AS74 convective closure assumption. While BATS1e does capture the seasonal cycle of total runoff, gross errors in the partitioning of total runoff between surface runoff and groundwater runoff exist. The seasonal cycle of root zone soil moisture simulated by RegCM3 using IBIS and the AS74 convective closure assumption is dry, but agrees with observations during the summer. The rest of the models underestimate root zone soil moisture.  相似文献   
106.
107.
Mantle-derived garnets recovered in diamond exploration programs show compositional variations in Cr, Ca, Mg, Fe and Ti that reflect the chemical, physical and lithological environments in which they occur, occasionally together with diamond. The association of diamond with mantle garnet has progressed through a number of geochemical advances, most notably those of Dawson and Stephens (1975) and Gurney (1984), which are integrated in this work with less well known petrological advances made primarily in xenolith and experimental petrology. A simple, robust garnet classification scheme is formulated which accommodates empirical garnet–diamond relationships for peridotitic (G10, G9, G12), megacrystic (G1), Ti-metasomatised (G11), pyroxenitic (G4, G5) and eclogitic (G3) lithologies in eight distinct garnet classes. The calcium-saturation characteristics of harzburgitic (G10), lherzolitic (G9) and wehrlitic (G12) garnets are described by a Ca-intercept projection that also shows promise as a relative barometer for garnet lherzolite (Grütter and Winter, 1997). Thermobarometric aspects of garnet–diamond associations are highlighted in the scheme through the use of the minor elements Mn and Na, though analysis by anything other than an electron microprobe is not required for classification. A “D” suffix is added to the G10, G4, G5 or G3 categories to indicate a strong compositional and pressure–temperature association with diamond. The scheme remains open to improvement, particularly with regard to delineation of pyroxenitic (or websteritic) diamond associations and to advances in Ca-in-garnet and Na-in-garnet thermobarometry.  相似文献   
108.
109.
Summary Absolute measurements of gravity have been made at 6 locations ranging from Ottawa, Ont., in southern Canada, to Alert, N.W.T., the world's most northerly permanent settlement, as part of a program to provide scale and level for the Canadian Gravity Standardization Network (CGSN). Except at Resolute, N.W.T., CGSN-74 gravity values, upon which our gravity reductions are currently based, agree with the absolute gravity meter results to within about .25µm/s2. The scale of our CGSN-80 gravity network, upon which our spring-balance type gravity meter scale constants are derived, agrees with the scale defined by the absolute gravity measurements to within about one part in ten thousand.  相似文献   
110.
The flux of suspended particulate material across the mouth of a well-mixed estuary was measured over 12 months. Samples were taken over one neap and one spring tidal cycle each month and analysed for total suspended particulate material, inorganic and organic particulates, particulate organic carbon and particulate organic nitrogen. Water volume transport at discrete time-steps were determined by means of a one-dimensional hydrodynamic model, calibrated for each tidal cycle sampled. Net transport varied between tidal cycles with regard to direction (import or export) and magnitude. Annual budgets revealed a net export of 5306 tonne of total suspended particulate material (3900 tonne of inorganic particulates, 1286 tonne of particulate organic carbon and 120 tonne of particulate organic nitrogen). The sources of particulate organic carbon are mainly from saltmarshes (194 g POC m2y1) and from intertidal invertebrate production (586 g POC m−2y−1).  相似文献   
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