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81.
82.
Abstract– In this edition of The Meteoritical Bulletin, a total of 506 newly approved meteorite names with their relevant data are reported. These include 354 from northwest Africa, 31 from the Americas, 15 from Antarctica (Koreamet), 85 from Asia, 20 from Australia, and 1 from Europe. Among these meteorites are 2 falls, Grimsby (Canada) and Santa Lucia (2008) (Argentina). Also described are a CM with low degree of alteration, new ungrouped chondrites and achondrites, and 4 Martian meteorites.  相似文献   
83.
Time Series Data Server (TSDS) is a software package for implementing a server that provides fast super-setting, sub-setting, filtering, and uniform gridding of time series-like data. TSDS was developed to respond quickly to requests for long time spans of data. Data may be served from a fast database, typically created by aggregating granules (e.g., data files) from a remote data source and storing them in a local cache that is optimized for serving time series. The system was designed specifically for time series data, and is optimized for requests where the longest dimension of the requested data structure is time. Scalar, vector, and spectrogram time series types are supported. The user can interact with the server by requesting a time series, a date range, and an optional filter to apply to the data. Available filters include strides, block average/minimum/maximum, exclude, and inequality. Constraint expressions are supported, which allow such operations as a request for data from one time series when a different time series satisfied a specified relationship. TSDS builds upon DAP (Data Access Protocol), NcML (netCDF Mark-up language) and related software libraries. In this work, we describe the current design of this server, as well as planned features and potential implementation strategies.  相似文献   
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85.
Abundant dykes in the southern Etendeka region, NW Namibia,mostly contain 8–20% MgO. Almost all can be allocatedto previously described Early Cretaceous magma types. Horingbaai-typebasalts–picrites occur up to 120 km inland. Some havesuperficially mid-ocean ridge basalt (MORB)-like compositions:(La/Nb)n  相似文献   
86.
Impacts of the forces and processes of agricultural restructuring are described in this paper through an analysis of farmers’ ‘lived experience’ in the tobacco sector of Ontario, Canada. The paper argues that the political and economic changes in the 1980s fundamentally altered tobacco farming and the broader rural community. The analysis is based upon a survey of farmers and former farmers, and includes examples of individual case histories. The results show the ways in which farmers’ well-being was affected and provides insights into coping mechanisms.  相似文献   
87.
In conventional economic terms, the withdrawal of government support for agriculture in 1984 may have resulted in a revitalised and stronger farm sector. This paper uses evidence gathered from 16 case study farms in the Tararua District to argue that such a perspective ignores the long-term social and environmental impact of the policy reforms. It questions whether New Zealand's commitment to sustainable agriculture can be met without comprehensive public policies that address the underlying social and economic causes of environmental damage.  相似文献   
88.
The ankaramitic scoria and carbonatite tuffs of the Lashainevolcano, northern Tanzania, contain a suite of alkalic pyroxenitexenoliths, in addition to the previously investigated magnesianlherzolite types. The rocks of the pyroxenite suite, which includemica-dunite and iron-rich lherzolite, consist of varying combinationsof olivine (Fo86–72), sodic diopside, Ti-pargasite, Ti-phlogopite,ilmenite, chromite, and magnetite. The over-all assemblagesare poorer in alumina than those from other alkalic pyroxenitelocalities. Comparison with the products of experimentally investigatedsystems is difficult because of low alumina, and emphasizesthe need for experimental syntheses on rocks of this type.  相似文献   
89.
90.
Burial Metamorphism in the Hamersley Basin, Western Australia   总被引:3,自引:0,他引:3  
The low-grade metamorphic minerals prehnite, pumpellyite, epidoteand actinolite in rocks of basic and intermediate compositionhave a broad, systematic distribution in the Hamersley Basin.Assemblages of these minerals are wisespread in the FortescueGroup, the lowermost group in the Hamersley Basin. Because ofsunsuitability of rock type no relevant mineral assemblageswere observed in samples from the Hamersley Group. However,metamorphism of this group can be implied from mineral assemblagesin the younger Turee Creek Group, and because the HamersleyGroup conformably overlies the metamorphosed Fortescue Group. Unfolded stratigraphic cross sections show that depth of burialwas the dominant control of increase in metamorphic grade. Fourmetamorphic zones are defined over a relative depth of burialof 9 km. From lowest grade to highest these are: Zone I (ZI)prehnite–pumpellyite zone; ZII, prehnite–pumpellyite–epidotezone; ZIII, prehnite–pumpellyite–epidote–actinolitezone; and ZIV, (prehnite–epidote–actinolite zone.Laumontite, definitive of the zeolite fades is absent but thatpart of the sequence may coincide with rocks of unsuitable composition,or may have been removed by erosion. A large area of prehnite–pumpellyitefades (ZI and ZII) dominates the north side of the basin, whilegreenschist fades (ZIV) dominates the south. Separating thetwo is a curved central strip of pumpellyite-actinolite facies(ZIII). Microprobe data of pumpellyites from the three pumpellyite–bearingzones, ZI, II and III, show two systematic trends: extensivevariation in Al/Fe ratios at any one grade, and a general decreaseof Mg with increasing metamorphism. Consideration of the compositionsof the most abundant pumpellyites in the metabasic rocks showsthat these two trends spread about a more fundamental lineartrend towards AJ-enrichment with increasing metamorphism astotal Fe and Mg decrease. Epidote shows a wide range in Fe content in ZII and ZIII (Ps15to Ps40) crossing the miscibility gap proposed by Raith (1976).In ZIV epidote compositions are more aluminous and restrictedin composition (Ps11 to Ps20). Magnesium has entered the epidotelattice in ZII and ZIII (up to 0–17 ions Mg where £cations = 8) but to only half this in ZIV. Synthesis of the burial model with published experimental workputs constraints on the ancient thermal gradient that existedduring burial metamorphism. For the peak of metamorphic adjustmentfluid pressure appears to have been equal to load pressure.A relatively high gradient of 80 to 100 deg;C/km seems likelyfor the shallow part of the sequence, with a gradient of 40deg;C/km for the deeper part of the sequence, the change beingat about 2–5 km. The prehnite-pumpellyite facies correspondsto a fluid pressure of 0–5 to 1 kilobar and a temperaturerange of about 100 to 300 deg;C. The prehnite-bearing pumpellyite-actinolitefacies is interpreted to have developed at about 1–5 kbover a temperature range of 300 to 360 deg;C. This facies isprobably a low pressure subfacies of the pumpellyite-actinolitefades of Hashimoto (1966).  相似文献   
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