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991.
A computational scheme is developed for estimating turbulent surface stress, sensible heat flux and humidity flux from mean velocity, temperature and humidity at a single height in the atmospheric surface layer; conditions at this reference level are presumed known from observations or from a numerical atmospheric circulation model. The method is based on coupling a Monin-Obukhov similarity profile to a force-restore formulation for the evolution of surface soil temperature to yield the local values of shear stress, heat flux and surface temperature. A self-contained formulation is presented including parameterizations for solar and infrared radiant flux at the surface.In addition to reference-level mean flow properties, the parameters needed to implement the scheme are thermal heat capacity of the soil, surface aerodynamic roughness, latitude, solar declination, surface albedo, surface emissivity and atmospheric transmissivity.Sample calculations are presented for (a), constant atmospheric forcing at the reference level, and (b) variable atmospheric forcing corresponding to Kahle's (1977) measurements of windspeed, air temperature and radiometer soil surface temperature under dry vegetatively sparse conditions in the Mohave Desert in California. The latter case simulated the observed diurnal variations resonably well for the parameters used.Consultant, Atmospheric Sciences Division, Department of Energy and Environment, Brookhaven National Laboratory, Upton, N.Y., pc11973, U.S.A. 相似文献
992.
Martin Robert F. Whitley John E. Woolley Alan R. 《Contributions to Mineralogy and Petrology》1978,66(1):69-73
Examples of fenitization of pure quartzites provide valuable insight into the relative mobility of elements. This investigation of fenites from the Borralan complex shows that rare-earth elements are mobile and added during fenitization of quartzite. The resulting normalized patterns are distinctive in their enrichment of the light rare earths and steep drops in the interval Nd-Eu. In terms of rare-earth geochemistry, no difference can be found between the sodic and the potassic trends of fenitization at Borralan. Concentrations of mobile elements define straight-line plots through the origin, heretofore considered a criterion indicative of a fractional crystallization process.Present address: Department of Geological Sciences, McGill University, 3450 University Street, Montreal, Que. H3A 2A7, Canada 相似文献
993.
In most lakes, phosphorus (P) is the nutrient controlling the trophic state. Thus, for effective control of eutrophication, the uncertainty in P-loading should be encoded as a probability density function (pdf). Specifically, the pdf of P-loading Y from non-point agricultural sources is sought by means of an event-based stochastic model.P-loading events are triggered by precipitation events (X1, X2, T), in which X1 is the rainfall amount, X2 the duration, and T the interarrival time between events. (X1, X2) are dependent random variables, while T is assumed to be exponentially distributed. The precipitation event causes runoff, which carries dissolved P into the lake with a concentration C1 and sediment yield, Z, which carries fixed or sorbed P into the lake in a fraction C2 of Z. Seasonal loading of P is calculated by adding random numbers of random variables. The model accounts separately for dissolved P and sorbed P. Explicit expressions are given for the mean and variance of each type of P-loadings. The case study of a sub-watershed of Lake Balaton, Hungary, is used to illustrate the methodology. Precipitation data, empirical rainfall-runoff-sediment yield relationships and a small number of observations of events are used to calibrate the model and estimate the means and variances of loading per event and per season. Then a simulation method is used to estimate complete pdf of these random variables. Use of the model for alternative methods of controlling P-loading is briefly discussed, as well as the economics of control. 相似文献
994.
Dr. A. Dal Negro Dr. G. Giuseppetti Dr. J. M. Martin Pozas 《Mineralogy and Petrology》1974,21(3-4):246-260
Summary Sarkinite is a basic manganese arsenate, Mn2AsO4(OH). The lattice parameters are:a=12.779 (2) Å,b=13.596 (2) Å,c=10.208 (2) Å, =108°53 (6). Space groupP21/a,Z=16. The crystal structure has been solved by direct methods from three-dimensional X-ray diffractometer data and refined by least-squares methods toR=0.052 for 3519 independent reflections. The crystal structure is built up by a three-dimensional framework of MnO4(OH)2 octahedra, MnO4(OH) trigonal bipyramids and AsO4 tetrahedra, as found in wagnerite. Isotypy of sarkinite with triploidite is confirmed.
With 1 Figure 相似文献
Die Kristallstruktur des Sarkinits, Mn2AsO4(OH)
Zusammenfassung Die Kristallstruktur des basischen Manganarsenates Sarkinit, Mn2AsO4(OH), mit den Gitterkonstantena=12,779 (2) Å,b=13,596 (2) Å,c=10,208 (2) Å, =108°53 (6). RaumgruppeP21/a,Z=16, wurde mit dreidimensionalen Röntgendiffraktometermessungen durch direkte Methoden gelöst und nach dem kleinste-Quadrate-Verfahren verfeinert (R=0,052 für 3519 unabhängige Reflexe). Die Struktur besteht aus einem dreidimensionalen Gerüst aus MnO4(OH)2-Oktaedern, trigonalen Bipyramiden von MnO4(OH) und AsO4-Tetraedern wie in Wagnerit. Die Isotypie von Sarkinit mit Triploidit wurde bestätigt.
With 1 Figure 相似文献
995.
A little known observation that exposure to sublethal concentrations of detergent cause fatal abnormalities in the second generation of a polychaete has been followed up and similar abnormalities have been observed in the first or second generation of larvae exposed to sublethal concentrations of copper and zinc. Few toxicity tests extend beyond the responses of the exposed individuals. The discovery of a delayed reaction to sublethal concentrations of common contaminants of the sea has unknown but potentially important ecological implications. 相似文献
996.
Martin Schwarzbach 《International Journal of Earth Sciences》1960,49(1):103-108
Zusammenfassung Am Beispiel des Squantum-Tillits bei Boston wird gezeigt, welche Schwierigkeiten paläoklimatologische Zeitmarken bieten können. Nur im Quartär (und in gewissem Umfange auch im Tertiär) leisten sie gute stratigraphische Dienste.
Dank. Exkursionen in diesem Gebiet wurden mir finanziell durch eine Beihilfe der Deutschen Forschungsgemeinschaft ermöglicht. Für viele Hilfe in Boston bin ich ferner vor allem Prof. R. R.Shhock, M. T. L, Cambridge (Mass.) zu großem Dank verpflichtet. 相似文献
By the example of the Squantum tillite near Boston may be demonstrated some of the difficulties connected with paleoclimatologic time-markers. Only in the Quaternary (and, to a certain degree, also in the Tertiary) they may be successfully used for stratigraphic purposes.
Dank. Exkursionen in diesem Gebiet wurden mir finanziell durch eine Beihilfe der Deutschen Forschungsgemeinschaft ermöglicht. Für viele Hilfe in Boston bin ich ferner vor allem Prof. R. R.Shhock, M. T. L, Cambridge (Mass.) zu großem Dank verpflichtet. 相似文献
997.
Martin Rodewald 《Ocean Dynamics》1957,10(4):151-157
Zusammenfassung Das Jahr 1955 zeichnete sich im Pazifischen Ozean durch eine negative Anomalie des Oberflächenwassers von ungeheurer Ausdehnung und großer Beharrlichkeit aus. Ihre räumliche Anordnung und zeitliche Entwicklung wird in großen Zügen beschrieben.
The cooling of the surface waters in the Pacific Ocean in 1955
Summary In 1955, the surface waters in the Pacific were characterized by a negative anomaly of immense extension and strong persistency. Its distribution in space and its development in time are roughly outlined.
Le refroidissement des eaux de surface de l'Océan Pacifique en 1955
Résumé En 1955, les eaux de surface du Pacifique étaient caractérisées par une anomalie négative d'immense étendue et de forte persistance. On décrit en grandes lignes sa distribution dans l'espace et son développement dans le temps.相似文献
998.
Martin Rodewald 《Ocean Dynamics》1957,10(4):147-151
Zusammenfassung Es werden neue Jahrfünftmittel der Oberflächentemperatur für die pazifische Küste Nordamerikas mitgeteilt, die den Zeitraum von mindestens dreißig Jahren (bis einschließlich 1955) umfassen. Die fortschreitenden Jahrfünftmittel lassen Fluktuationen, aber keinen säkularen Trend erkennen. Die seit dem Maximum von 1941 allgemein aufgetretene Abkühlung machte die letzten zehn Jahre 1946–55 zu den durchschnittlich kältesten seit Beginn der zwanziger Jahre. Der Tiefpunkt scheint jedoch bei den meisten Stationen überschritten zu sein. Einzelne besonders ausgeprägte Warmwasser- (und Kaltwasser-) Jahre erstrecken sich offensichtlich über die gesamte Küste von Kalifornien bis Alaska. An dem Beispiel von 1926 wird gezeigt, daß hier eine globale atmosphärische Zirkulationsanomalie ursächlich war, die in ganz ähnlicher Weise auch eine starke Wassererwärmung im östlichen subtropischen Nordatlantik gezeitigt hatte.
Temperatures of surface waters on the Pacific coast of North America, 1920–1955
Summary This paper presents recent five-year mean values of sea-surface temperatures from the Pacific coast of North America for a period of at least thirty years (including the year 1955). The five-year running means reveal the occurrence of fluctuations rather than the existence of a secular trend. Decreasing temperatures which have been generally observed since the maximum of sea temperature in 1941 made the last ten years from 1946 to 1955 the coldest years since the beginning of the twenties of this century. It seems, however, that at most stations, temperatures already exceeded the minimum. Throughout separate years, a pronounced warming (or a pronounced cooling) of sea-surface water obviously extended over the whole length of the Pacific coast from California to Alaska. The example of 1926 shows that in this case the high temperatures are caused by a worldwide atmospheric circulation anomaly which, in a similar way, accounts for the high values of sea-surface temperatures in the eastern subtropical part of the North Atlantic Ocean.
Les températures superficielles des eaux côtières pacifiques de l'Amérique du Nord de 1920 à 1955
Résumé Pour une période de trente années (y compris l'anné de 1955) le travail actuel présente de récentes valeurs moyennes de cinq années des températures de surface mesurées sur la côte Pacifique de l'Amérique du Nord. Les moyennes progressives de cinq années montrent la présence des variations plutôt que l'existence d'un trend séculaire. Causé par le refroidissement des eaux de surface qui s'est produit partout depuis le maximum de la température en 1941, les derniers dix ans de 1946 à 1955 ont été au moyen les plus froids dès le début de la décade de 1920 à 1930. Il semble, cependant, qu'auprès de la plupart des stations, les températures aient déjà dépassé le minimum. Pendant plusieurs années isolées, un échauffement prononcé (ou un refroidissement prononcé) des eaux de surface s'étend tout le long de la côte Pacifique de la Californie jusqu'à l'Alaska. L'exemple de 1926 montre que dans ce cas les températures élevées furent causées par une anomalie universelle de la circulation atmosphérique qui, d'une manière analogue, provoqua également un échauffement des eaux de surface dans la région orientale subtropicale de l'Atlantique du Nord.相似文献
999.
1000.
The Murchison meteorite contains aliphatic and aromatic hydrocarbons similar to those made in static Fischer-Tropsch-type syntheses. Principal compound classes above C8 are n-alkanes, mono- and dimethylalkanes, alkenes, alkylbenzenes and -naphthalenes. Below C8, n-alkanes are virtually absent; instead, benzene, toluene, branched alkanes dominate. The CH4/C2H6 ratio is greater than 30, possibly greater than 700. Isoprenoids from C17 to C20 occur in a surface rinse but not in subsequent extracts and appear to be terrestrial contaminants. Thiophenes, porphyrin-like pigments and chlorobenzenes were also found; the latter appear to be contaminants. In the Allende meteorite, only methane, benzene, toluene and an aromatic polymer seem to be indigenous. 相似文献