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81.
82.
Irie K Kawaguchi M Mizuno K Song JY Nakayama K Kitamura S Murakami Y 《Marine pollution bulletin》2011,63(5-12):297-302
Heavy oil (HO) on the sea surface penetrates into fish eggs and prevents the normal morphogenesis. To identify the toxicological effects of HO in the context of the egg types, we performed exposure experiments using floating eggs and sinking eggs. In the course of development, HO-exposed embryos of floating eggs showed abnormal morphology, whereas early larva of the sinking eggs had almost normal morphology. However, the developing peripheral nervous system of sinking eggs showed abnormal projections. These findings suggest that HO exposed fishes have problems in the developing neurons, although they have no morphological malformations. Through these observations, we conclude that HO is strongly toxic to floating eggs in the morphogenesis, and also affect the neuron development in both floating and sinking eggs. 相似文献
83.
40Ar/39Ar dating was conducted on the Da Lien granite related to greisen‐skarn type polymetallic (W‐CaF2‐Cu‐Bi‐Au) mineralization in Nui Phao, northern part of Vietnam in the South China Plate. Biotite and muscovite separates from the biotite‐muscovite granite and greisenized granite indicate four plateau ages: 82.2 ± 0.4 Ma, 82.8 ± 0.3 Ma, 81.5 ± 0.3 Ma and 82.5 ± 0.4 Ma. The plateau ages were not significantly influenced by excess 40Ar in dated minerals or by loss of radiogenic 40Ar due to hydrothermal activities. The results indicate that solidification of granite related to the polymetallic mineralization occurred in the Late Cretaceous between 82.8 Ma and 81.5 Ma. 相似文献
84.
Yoshiaki Kon Mihoko Hoshino Kenzo Sanematsu Sayaka Morita Maiko Tsunematsu Nobuyuki Okamoto Nobuhiko Yano Mikiya Tanaka Tetsuichi Takagi 《Resource Geology》2014,64(1):47-57
We have conducted geochemical and mineralogical investigations of the rare earth and yttrium (REY)‐rich mud from the Minami‐Torishima area in the Pacific in order to clarify the concentration of REY and their host‐phase in the mud. X‐ray diffraction analysis shows that the mud is mainly composed of phillipsite, fluorapatite, quartz, albite, illite and montmorillonite. Whole‐rock CaO, P2O5 and total REY contents of the mud are positively correlated. Relative abundance of apatite is also positively correlated to P2O5 and total REY contents. These correlations suggest that apatite is the main host of the P2O5 and REY in the mud. We make in situ compositional analyses of constituent minerals in the REY mud. The results show that the apatite is abundant in REY (9300–32,000 ppm) and is characterized by a negative Ce anomaly and enrichment in heavy rare‐earth elements. This abundance and composition of REY of the mud is similar those of fish debris apatites. In contrast, phillipsite is less abundant in REY (60–170 ppm). Therefore we conclude that the main REY host phase of the mud is apatite. 相似文献
85.
Kinya Hibino Toshisuke Kashiwagi Shoji Okuno Kaori Yajima Yukio Uchihori Hisashi Kitamura Takeshi Takashima Mamoru Yokota Kenji Yoshida 《Astrophysics and Space Science》2007,309(1-4):541-544
We have developed radiation detectors using the new synthetic diamonds. The diamond detector has an advantage for observations
of “low/medium” energy gamma rays as a Compton telescope. The primary advantage of the diamond detector can reduce the photoelectric
effect in the low energy range, which is background noise for tracking of the Compton recoil electron. A concept of the Diamond
Compton Telescope (DCT) consists of position sensitive layers of diamond-striped detector and calorimeter layer of CdTe detector.
The key part of the DCT is diamond-striped detectors with a higher positional resolution and a wider energy range from 10 keV
to 10 MeV. However, the diamond-striped detector is under development. We describe the performance of prototype diamond detector
and the design of a possible DCT evaluated by Monte Carlo simulations.
相似文献
86.
There is a continuous record of planktonic foraminifers for oxygen isotope stages 50 to 26 (ca. 1.5–1.0 Ma) in the early Pleistocene Omma Formation near Kanazawa City, Central Japan, on the Sea of Japan coast. The warm-water species Globigerinoides ruber entered the Sea of Japan with the Tsushima Current during all interglacial periods and went locally extinct in the succeeding glacial periods. This implies that the marine climate of the Sea of Japan varied predominantly with the 41,000-year period of Earth's orbital obliquity. However, the relative abundances of G. ruber in marine isotope stages 47, 43 and 31 are significantly higher than those in other interglacial stages. These stages correspond to periods when eccentricity-modulated precession extremes were aligned with obliquity maxima. The Tsushima Current is a branch of the warm Kuroshio Current which is the strong northwestern component of the subtropical North Pacific Ocean gyre. Our data imply that the early Pleistocene climate in the northwestern Pacific was influenced not only by obliquity cycles but also by eccentricity cycles. This study also supports the climate model regarding eccentricity's role in the origin of low-frequency climate changes before the late Pleistocene ice ages. 相似文献
87.
At the cool periphery of the solar nebula, oxygen could photochemically be formed from water. The mixing of17O and18O enriched by the self-shielding effect of16O2 to the dust grain melted by the shock waves there would explain the oxygen isotopic anomaly in the high-temperature mineral of the carbonaceous meteorites. 相似文献
88.
Dynamical behaviour of an evaporating black hole is investigated for a Vaidya-type metric. The Raychaudhuri equation is examined with including terms up to the second order in the luminosity near the event horizon. Such a solution is found that the luminosity increases as the mass decreases during the evaporation. 相似文献
89.
The frequency of the occurrence of the tangential discontinuity (TD) was investigated at thirteen interacting regions (the leading edges) of the solar wind, where each averaged value of the total pressure reaches very much higher values, ranging from 3 × 10?10 to 12 × 10?10 erg/m3, than the non-interacting regions (the troughs or the high velocity regions, ?2 × 10?10 erg/cm3).The present result that the degree of the occurrence is considerably higher in the interacting region than in the non-interacting region was confirmed to be consistent with our previous result. It was discovered that the occurrence frequency at the interacting region increases when strong interaction has occurred. 相似文献
90.
Kenzo Yagi J.F. Lovering Makoto Shima Akihiko Okada 《Meteoritics & planetary science》1978,13(1):23-45
The Yamato (j), (k), (l), and (m) meteorites collected from near the Yamato Mountains in December, 1973, are respectively an H-4 and L-5 chondrite, a howardite, and an L-5 chondrite. Yamato (l), the howardite, is a polymict breccia of diogenite and eucrite clasts. Olivine in the chondrites ranges in composition from Fo75 to Fo80, whereas in the howardite, where it is rare, the composition is about Fo60. Pyroxenes in the chondrites are mostly orthopyroxenes and (En83), while the pyroxenes in the howardite are more complex, comprising orthopyroxene, pigeonite, augite, and rare clinohypersthene (in the order of decreasing abundance), with the range from En80 to En37. They form a definite trend, probably formed by the fractional crystallization of the parental magma of the achondrite, and later subjected to exsolution phenomena during the slow cooling. Plagioclase is high-temperature oligoclase in the chondrites, and anorthite in the howardite. Maskelynitization is sometimes observed. Other shock effects are also observed. Opaque phases consist mostly of nickel-iron, troilite, chromite, and rarely ilmenite. Intergrowth of these minerals are common. The accessory minerals comprise quartz, cristobalite, apatite, spinel, and rare uranium-bearing minerals. The bulk composition and genetic significance are discussed. 相似文献