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151.
A REGIONAL MODEL STUDY OF THE VARIATIONS AND DISTRIBUTIONS OF OZONE AND ITS PRECURSORS ON EASTERN ASIA AND WEST PACIFIC OCEAN REGIONS
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A simulated study of mechanism for variations and distributions of ozone and its precursors was made by using thethree-dimensional regional Eulerian model.The results showed that the ozone production was controlled by NO,butthere is a complicated nonlinear relation between them.The photochemical reactions controlled by solar radiation arethe determinative factors affecting the variations of the surface ozone and its precursors.The relations of ozone and CO,PAN were studied.We compared the simulated and observed results during the PEM-WEST A in order to better under-stand the photochemical processes of ozone and its precursors. 相似文献
152.
盐湖卤水体系Li~+,Mg~(2+)/Cl~-,SO_4~(2-),borate 总被引:1,自引:0,他引:1
本文总结了作者对盐卤硼酸盐体系Li+,Mg2+/Cl-,SO42-,B4O7(2-)-H2O研究的结果,对该体系涉及的硼酸盐的合成、鉴定和性质进行了研究,并对这些盐在纯水及一些盐溶液中的存在形式进行了初步探索.完成了该体系所包含的一些次级体系的相平衡及溶液物化性质的研究.提出了一种镁硼酸盐Mg2B6O(11)·17H2O的新合成方法.首次发现三方硼镁石在水中的相转化是分两个阶段进行,从而证明了尼古拉耶夫在25℃MgO—B2O3-H2O体系研究中三方硼镁石与章氏硼镁石的共饱点,实际上是三方硼镁石向多水硼镁石发生相转化的一个动力学的平衡点,热力学的个稳点的观点. 相似文献
153.
本文主要论述CSAMT法在铲子坪铀矿床的应用效果、评价其地电模式,另外还对卡尼亚视电阻率(ρ_a)与相位差(φ)的探测深度、低阻中间层对探测深度的影响以及电磁波远近场数据的辩证认识等方法机理问题进行了探讨。 相似文献
154.
M.?ZhangEmail author H.?Xu E. K. H.?Salje P. J.?Heaney 《Physics and Chemistry of Minerals》2003,30(8):457-462
The structural behavior of -eucryptite (LiAlSiO4) has been investigated using infrared (IR) spectroscopy over a temperature range of 20 to 900 K and FT-Raman spectroscopy at room temperature. IR reflectance measurements show that -eucryptite possesses high reflectivity in the far-IR region, as is consistent with its reported superionic conductivity along the c-axis. On heating, the Li-related IR bands near 246 and 300 cm–1 (with A2 symmetry) broadened and weakened dramatically, presumably as a result of Li+ positional disordering along the structural channels parallel to c. The disordering process appears to induce a framework distortion, as is evidenced by the broadening of some vibrations of Si(Al)–O with increasing temperature. A change in slope in the temperature dependence of the phonon frequency near 300 cm–1 and the linewidth of the 760 cm–1 band at 715 K indicates that Li becomes completely disordered above this temperature. In addition, the temperature dependence of the linewidth for the 760 cm–1 band exhibits an additional change in slope at 780 K, implying the existence of an intermediate state within this temperature range. The detailed structure of this intermediate phase, however, needs further study. Our IR data provide no indication of structural changes between room temperature and 20 K. 相似文献
155.
156.
157.
瞬态面波技术在冲洪积层勘察中的应用 总被引:2,自引:0,他引:2
瞬态面波技术具有速度快、精度高、对场地要求低等特点。采用适宜的工作参数和技术方法,在冲洪积层勘察中可较好地了解其物质分布,从而进行场地土类划分及评价、饱和砂土液化分析等,为设计、施工提供各层位物理力学指标等参数,亦为抗震设计提供场地卓越周期等资料,补充和丰富工程勘察资料,提高精度,缩短工程周期。 相似文献
158.
Norimasa Nishiyama Robert Paul Rapp Tetsuo Irifune Takeshi Sanehira Daisuke Yamazaki Ken-ichi Funakoshi 《Physics and Chemistry of Minerals》2005,32(8-9):627-637
In situ X-ray diffraction measurements of KAlSi3O8-hollandite (K-hollandite) were performed at pressures of 15–27 GPa and temperatures of 300–1,800 K using a Kawai-type apparatus. Unit-cell volumes obtained at various pressure and temperature conditions in a series of measurements were fitted to the high-temperature Birch-Murnaghan equation of state and a complete set of thermoelastic parameters was obtained with an assumed K′300,0=4. The determined parameters are V 300,0=237.6(2) Å3, K 300,0=183(3) GPa, (?K T,0/?T) P =?0.033(2) GPa K?1, a 0=3.32(5)×10?5 K?1, and b 0=1.09(1)×10?8 K?2, where a 0 and b 0 are coefficients describing the zero-pressure thermal expansion: α T,0 = a 0 + b 0 T. We observed broadening and splitting of diffraction peaks of K-hollandite at pressures of 20–23 GPa and temperatures of 300–1,000 K. We attribute this to the phase transitions from hollandite to hollandite II that is an unquenchable high-pressure phase recently found. We determined the phase boundary to be P (GPa)=16.6 + 0.007 T (K). Using the equation of state parameters of K-hollandite determined in the present study, we calculated a density profile of a hypothetical continental crust (HCC), which consists only of K-hollandite, majorite garnet, and stishovite with 1:1:1 ratio in volume. Density of HCC is higher than the surrounding mantle by about 0.2 g cm?3 in the mantle transition zone while this relation is reversed below 660-km depth and HCC becomes less dense than the surrounding mantle by about 0.15 g cm?3 in the uppermost lower mantle. Thus the 660-km seismic discontinuity can be a barrier to prevent the transportation of subducted continental crust materials to the lower mantle and the subducted continental crust may reside at the bottom of the mantle transition zone. 相似文献
159.
C. M. Holl J. R. Smyth M. H. Manghnani G. M. Amulele M. Sekar D. J. Frost V. B. Prakapenka G. Shen 《Physics and Chemistry of Minerals》2006,33(3):192-199
Fe-bearing dense hydrous magnesium silicate Phase A, Mg6.85Fe0.14Si2.00O8(OH)6 has been studied by single-crystal X-ray diffraction at ambient conditions and by high-pressure powder diffraction using synchrotron radiation to 33 GPa. Unit cell parameters at room temperature and pressure from single crystal diffraction are a=7.8678 (4) Å, c=9.5771 (5) Å, and V=513.43 (4) Å3. Fitting of the P–V data to a third-order Birch-Murnaghan isothermal equation of state yields V
0=512.3 (3) Å3, K
T,0=102.9 (28) GPa and K′=6.4 (3). Compression is strongly anisotropic with the a-axes, which lie in the plane of the distorted close-packed layers, approximately 26% more compressible than the c-axis, which is normal to the plane. Structure refinement from single-crystal X-ray intensity data reveals expansion of the structure with Fe substitution, mainly by expansion of M-site octahedra. The short Si2–O6 distance becomes nearly 1% shorter with ~2% Fe substitution for Mg, possibly providing additional rigidity in the c-direction over the Mg end member. K
T obtained for the Fe-bearing sample is ~5.5% greater than reported previously for Fe-free Phase A, despite the larger unit cell volume. This study represents a direct comparison of structure and K
T–ρ relations between two compositions of a F-free dense hydrous magnesium silicate (DHMS) phase, and may help to characterize the effect of Fe substitution on the properties of other DHMS phases from studies of the Fe-free end-members. 相似文献
160.
Igor R. Shein Konstantin I. Shein Alexander L. Ivanovskii 《Physics and Chemistry of Minerals》2006,33(8-9):545-552
The structural, electronic properties and stability of thorium orthosilicate ThSiO4 polymorphs: thorite and huttonite are investigated by means of the full-potential linearized augmented-plane-wave method with the generalized gradient approximation for the exchange-correlation potential (FLAPW-GGA). The forbidden gaps of thorite and huttonite are estimated at about 7.8 and 7.6 eV, respectively. It is found that Th5f states in ThSiO4 partially overlap with occupied O2p bands. The data obtained showed that thorite is more stable than huttonite; in turn both ThSiO4 polymorphs are unstable with respect to their constituent binary oxides (thorianite ThO2 and α-quartz SiO2) in agreement with the experiments. The theoretical shapes of X-ray emission (XES) (Si,O)Kα,β spectra for thorite, huttonite as well as for SiO2 and ThO2 are calculated and discussed. We show that the XES spectroscopy near the (Si,O)K edge may be very useful technique not only for detailed investigation of the bulk-electronic structure of Th silicates but also for the phase analysis of complex mineral samples containing these species. 相似文献