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371.
372.
The heat waves of 2003 in Western Europe and 2010 in Russia, commonly labelled as rare climatic anomalies outside of previous experience, are often taken as harbingers of more frequent extremes in the global warming-influenced future. However, a recent reconstruction of spring–summer temperatures for WE resulted in the likelihood of significantly higher temperatures in 1540. In order to check the plausibility of this result we investigated the severity of the 1540 drought by putting forward the argument of the known soil desiccation-temperature feedback. Based on more than 300 first-hand documentary weather report sources originating from an area of 2 to 3 million km2, we show that Europe was affected by an unprecedented 11-month-long Megadrought. The estimated number of precipitation days and precipitation amount for Central and Western Europe in 1540 is significantly lower than the 100-year minima of the instrumental measurement period for spring, summer and autumn. This result is supported by independent documentary evidence about extremely low river flows and Europe-wide wild-, forest- and settlement fires. We found that an event of this severity cannot be simulated by state-of-the-art climate models.  相似文献   
373.
The relationship between decadal variations in the North Atlantic meridional overturning circulation (MOC) and North Atlantic/Western European windstorm activity during the extended winter season is studied. According to an ensemble of three 240-year long simulations performed with the ECHAM5-MPIOM model, periods of high decadal windstorm activity frequently occur in the years following a phase of weak MOC (i.e. when the MOC starts to recover). These periods are characterised by a distinctive pattern in the mixed layer ocean heat content (OHC). A positive anomaly is located in the region 45°N?52°N/35°W?16°W (west of France). Negative anomalies are located to the North and South. The signal can be detected both in the heat content of the oceanic mixed layer and in the sea surface temperatures. Its structure is consistent with anomalously enhanced baroclinic instability in the region with the strong negative OHC gradient (30°W?10°W/45°N?60°N), which eventually produces a higher probability of windstorms.  相似文献   
374.
375.
A series of triaxial compression tests, triaxial extension tests, and triaxial compression creep tests were conducted to evaluate the strength, deformability, and permeability of rock salt from the Jintan location. Based on a previous analysis, the measured data can be physically modeled very well as shown by the constitutive model Hou/Lux and indicate that China’s representative bedded rock salt from the Jintan location is characterized by good ductility and deformation properties, similar to the European high-purity rock salt. Based on a comparison of compression as well as extension failure strength determined at rock salt from Jintan location, a similarity of compression and extension failure strength could be demonstrated. Permeation flow seems to be an anisotropic process because the permeability measured at samples prior to failure by compression tests differs to those measured at samples prior to failure by extension tests. The anisotropy of damage and destruction of rock salt has a significant influence on permeability. In case of triaxial compression tests, the measured permeability increases two to six orders of magnitude because of consistent direction of injection and cracks. In case of triaxial extension tests, however, the permeability increases less with a maximum of two orders in magnitude. The test results are significant for understanding the load-bearing behavior of rock salt from Jintan location and investigations with reference to the stability and tightness of underground caverns.  相似文献   
376.
The biodegradation of various wastewater-derived organic trace pollutants occurring in different aquatic compartments of the environment was previously reported to be influenced by the prevailing redox conditions. However, comparative studies on the redox-dependent degradation behavior of organic trace pollutants are scarce. The objective of the study presented herein, was to compile and evaluate data from several comparable previous tank experiments, thus, providing an overview on the redox-dependent removal of a total of 27 wastewater-derived trace compounds, including phenazone type compounds, antimicrobials, ß-blockers, psychoactive drugs and sulfonamides. Removal rate constants were fitted assuming first-order degradation kinetics. Six compounds were identified to be removed solely under oxic, three compounds solely under anoxic conditions. Others persisted under all experimental conditions, while some were removed under both oxic and anoxic conditions.  相似文献   
377.
Normative mineralogical calculations from bulk geochemistry of sedimentary rocks are problematic because of variable depositional environments, particle hydraulics and sedimentary source systems. The development of SEDMIN, a Microsoft Excel? spreadsheet solution, is a practical attempt for a computational routine focusing specifically on smectite, chlorite, kaolinite, illite and the ambiguous sericite within various pelitic sedimentary lithologies. While in essence a mathematical approach, the use of statistical evaluation of empirical lithogeochemical data combined with modal analytical procedures yields reasonable geochemical associations, more precise chemical phases and revised procedural allotment paradigms. Thus, an algorithm using TiO2 as a key to the normative calculation of kaolinite is proposed. Incorporating additional parameters, such as LOI (Loss-on-ignition) in conjunction with carbon, sulfur, carbonate and sulfate, provides that clay phases can be more accurately determined than from bulk oxides alone. Even when presented with atypical sample data, the spreadsheet solution is able to accurately predict predominant clay minerals. Besides some drawbacks, the likely benefit from SEDMIN is the incorporation of results in classification norms and diagrams indicative of sedimentary lithologies. The ”SEDMIN Sedimentary Mineral Calculator.xlsx” spreadsheet can be freely downloaded from http://earthscienceeducation.net/SEDMINSedimentaryMineralCalculator.xlsx.  相似文献   
378.
Abstract– The near‐circular Colônia structure, located in the southern suburbs of the mega‐city of São Paulo, Brazil, has attracted the attention of geoscientists for several decades due to its anomalous character and the complete absence of any plausible endogenous geologic explanation for its formation. Origin by impact cratering has been suggested repeatedly since the 1960s, but no direct evidence for this has been presented to date. New seismic data have been recently acquired at Colônia, providing new insights into the characteristics and possible layering of infill of the structure, as well as into the depth to the underlying basement. We review the current knowledge about the Colônia structure, present the new seismic data, and discuss the existing—as yet still indirect—evidence for a possible origin by an impact. The new data suggest the existence of a sedimentary fill of approximately 275 m thickness and also the presence of two intermediate zones between sediment and basement: an upper zone that is approximately 65 m thick and can be interpreted as a possible crater‐fill breccia, whereas the other zone possibly represents fractured/brecciated basement, with a thickness of approximately 50 m. Although this depth to basement seems to be inconsistent with the expected geometry of a simple, bowl‐shape impact structure of such diameter, there are a number of still unconstrained parameters that could explain this, such as projectile nature, size and velocity, impact angle, and particularly the current erosion depth.  相似文献   
379.
The results presented in this paper on uranium in bottled and tap water were determined within the scope of the project “European Groundwater Geochemistry: Bottled Water” of the Geochemistry Expert Group of EuroGeoSurveys. The analyses of bottled water provide an inexpensive approach to obtain information about European groundwater geochemistry. For this study, the uranium concentrations in 1785 European mineral water samples were analyzed by ICP–QMS in the BGR laboratories. The dataset is used to obtain a first impression about natural concentration levels and variation of uranium in groundwater (and bottled water) at the German and European scale.  相似文献   
380.
Using single-crystal X-ray diffraction at 293, 200 and 100 K, and neutron diffraction at 50 K, we have refined the positions of all atoms, including hydrogen atoms (previously undetermined), in the structure of coquimbite ( $ P {\bar 3}1c $ , a?=?10.924(2)/10.882(2) Å, c?=?17.086(3) / 17.154(3) Å, V?=?1765.8(3)/1759.2(5) Å3, at 293 / 50 K, respectively). The use of neutron diffraction allowed us to determine precise and accurate hydrogen positions. The O–H distances in coquimbite at 50 K vary between 0.98 and 1.01 Å. In addition to H2O molecules coordinated to the Al3+ and Fe3+ ions, there are rings of six “free” H2O molecules in the coquimbite structure. These rings can be visualized as flattened octahedra with the distance between oxygen and the geometric center of the polyhedron of 2.46 Å. The hydrogen-bonding scheme undergoes no changes with decreasing temperature and the unit cell shrinks linearly from 293 to 100 K. A review of the available data on coquimbite and its “dimorph” paracoquimbite indicates that paracoquimbite may form in phases closer to the nominal composition of Fe2(SO4)3·9H2O. Coquimbite, on the other hand, has a composition approximating Fe1.5Al0.5(SO4)3·9H2O. Hence, even a “simple” sulfate Fe2-x Al x (SO4)3·9H2O may be structurally rather complex.  相似文献   
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