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591.
Investigating adsorption of methyl parathion on the activated carbons Filtrasorb 400 and F 44 and on the adsorption polymer Wofatit Y 77 we found a stronger adsorption on the carbons at smaller concentration whereas the resin has the larger capacity at higher concentration. Adsorbents were regenerated through hydrolysis of the pesticide at pH = 11.7. The velocity of hydrolysis in the adsorbed state is reduced to a tenth of that in solution. However, a transport resistance in the pores of adsorbents seems to be negligible as may be concluded from the very small measured particle diameter dependence of the velocity constants. In adsorption-regeneration measurements the capacity of the adsorbents stabilized at about 70% of that of the fresh adsorbents. 相似文献
592.
593.
D. J. Stom S. S. Timofeeva N. F. Kashina L. J. Bielykh S. N. Souslov V. V. Boutorov M. S. Apartzin 《洁净——土壤、空气、水》1980,8(3):203-211
By the example of some phenols and qninones, in aqueous solutions possibilities for the quantitative determination are tested separately and in the mixture. Methods for thin-layer chromatography and spectrophotometry were developed. There can be chromatographically deteeted between 5 and 80 μg of substance. Phenol and quinone concentrations of 1.5 · 10?3 … 0.5 · 10?4 M were spectrophotometrically investigated. 相似文献
594.
G. Bergametti A.L. Dutot J.P. Quisefit R. Vie Le Sage 《Journal of Volcanology and Geothermal Research》1983,15(4):355-367
A statistical analysis of volcanic aerosol based on 1,083 variables including concentration, grain-size and site variabilities establishes correlations between sites and among chemical elements.Variation curves of element concentration show parallel behaviour. High coefficients of correlation between anions and cations confirm associations between elements. 相似文献
595.
Occurrence and field relations of an extensive ignimbrite sheet near Afyon in Central Anatolia are described. These rhyolitic ignimbrites are part of the important Neogene volcanic activity in Turkey and belong to the alignment of volcanic complexes along the inner border of the Taurian ranges. In close stratigraphical connection and in the same tectonic position as the rhyolites there occurs an assemblage of high-potassic, intermediate to basic volcanic rocks (alkali trachytes, mela-trachytes, latites and leucite-bearing rocks). Petrological and magmatological considerations led to the conclusion that the rhyolites and the potassic series, in spite of the close geological connection, are not related by processes of magmatic differentiation. Arguments in favour of an anatectic origin of the rhyolitic melt are presented. The occurrence of garnet and allanite as accessory minerals and as inclusions in the salic minerals of the ignimbrite are interpreted as relictic witnesses of a sialic parent rock. However, the trace elements, especially high Rb connected with low Sr, Ba and Zr and K/Rb ratios below 100 give a pattern generally explained by strong fractionation processes. 相似文献
596.
Based on phosphorus, iron and manganese analyses in 16 cores (5 dated) from the crest and flanks of the East Pacific Rise and the Bauer Deep we estimate that phosphorus is being deposited about 20 times faster in metalliferous sediments near the rise crest than in adjacent flank deposits, and about 40 times faster on the crest than in the Bauer Deep. Almost all of the phosphorus on the rise crest is contained in poorly crystallized hydrothermal iron oxyhydroxides, supporting Berner's (1973) proposal of phosphate sorption by these phases. The phosphate is probably derived from seawater, but some hydrothermal contribution cannot be excluded at this time. Flux estimates indicate that metalliferous sedimentation could remove 15–40% of the pre-agricultural river input of dissolved phosphate. 相似文献
597.
L. Steclaci 《Bulletin of Volcanology》1975,39(4):528-535
The frequency distributions of Pb, Zn, Cu in the hydrothermal sulphide deposits of the Baia Mare district are established. It is shown that the distribution of Pb is similar to that of Zn, unlike that of Cu. This law appears to be valid whatever the composition and grade of the ore, the type of the host rock, and the type of hydrothermal alterations. This law can provide arguments to establish the genesis of mineralizations of unknown origin. 相似文献
598.
I.N. Tolstikhin 《Earth and Planetary Science Letters》1975,26(1):88-96
A first-order degassing model was applied to describe the evolution of helium content and isotope composition in the earth and in the atmosphere. The main events described by the model are: (1) the earth-trapped primordial rare gases at the moment of its accretion; (2) later, the solid earth lost primordial and radiogenic rare gases, and (3) they were accumulated in the atmosphere; (4) in addition,3He was formed in the atmosphere due to cosmic irradiation, accretion from solar wind, etc.; (5)3He and4He dissipated into space at different loss rates.Study of this model confirms the concept that some of primordial helium is retained in the interior of the earth; terrestrial helium (3He/4He~ 2 × 10?5) was most probably formed as a mixture of primordial (3He/4He= 3 × 10?4) and radiogenic (3He/4He~ 3 × 10?8) helium. For achondritic concentrations of heavy radioactive elements (U= 2.25 × 10?8g/g) the calculated4He flux from the earth is equal to 5.7 × 106 at cm?2 sec?1. The corresponding3He flux is about 114 at cm?2 sec?1. In discussing the aeronomic problem of helium it is necessary to take into account that the earth is the main source of the light helium isotope. 相似文献
599.
600.
Green clinopyroxenes, commonly rounded and anhedral and richer in Fe, Na and Mn than the pyroxenes of the surrounding groundmass are a common feature of mafic alkaline volcanic rocks (e.g. basanites, monchiquites, leucitites). Some are accompanied by one or more of the following phases: Fe-rich kaersutite and biotite, anorthoclase, sodic plagioclase, apatite, magnetite, sphene, which are believed to be cognate with the green pyroxenes. We review evidence that these minerals have crystallized from mugearite, trachyte or phonolite magmas, and their presence in mafic alkaline rocks is due to magma mixing. The intermediate and salic magmas may sometimes be generated at mantle depths, possibly by melting of mantle material enriched in Fe, Na and volatiles. 相似文献