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61.
A 3×3 complete diallel cross comprising three families of the clam Meretrix meretrix(P1, P2 and P3) was used to determine the combining ability of parental families and heterosis of F1 under indoor and openair environments for growth traits. Analysis of variance for shell length and whole body weight indicated highly significant cross effects, environment effects and the interaction of cross by environment. General combining ability(GCA) and specific combing ability exhibited great variation among crosses and between two environments. Pooled over environments, P2 was the top combiner among the three parental families for both traits studied. The cross of P1 and P3 had the highest SCA. Additionally, significant reciprocal effects were observed. For individual environment, about half of the crossbred combinations showed favorable Mid-parent heterosis(MPH)(1%) for the shell length and whole body weight. Our data has shown that non-additive genetic and reciprocal effects constituted the major sources of genetic variation for both shell length and whole body weight, which indicates that crossbreeding among selective families could further explore the heterotic effects. 相似文献
62.
金枪鱼类是中西太平洋海域重要的经济鱼种,其中鲣产量约占到总产量的50%。本研究利用1995-2010年16年的中西太平洋(20°S~20°N,120°E~155°W)鲣围网生产统计数据和Niño3.4海区(5°S~5°N,120°~170°W)海表温度异常数据,对这16年鲣产量最高的十大渔区(5°×5°)进行时空格局分析,讨论渔场分布差异及CPUE与ENSO指数的关系。结果表明:16年间十大作业渔区主要分布在5°S~5°N、130°~175°E区域,这十大渔区产量占总产量的比重达47.5%,其中5°S~0°、155°~160°E,0°~5°N、130°~135°E,0°~5°N、135°~140°E及5°S~0°、160°~165°E等4个渔区产量占高产渔区产量的比重均超过10%,是中西太平洋重要的鲣产区。高产渔区的分布受海表温度影响较大,在厄尔尼诺时期,高产渔区分布明显偏东,主要分布在155°~180°E海域;在拉尼娜时期,高产渔区分布明显偏西,主要分布在130°~160°E海域。 相似文献
63.
The multi-band data covering optical, X-ray and γ-ray energy regions of 130 Fermi blazars in the First LAT AGN Catalog (1LAC) were collected to investigate the broadband spectral properties. The composite spectral indices show that HBLs have convex optical-to-X-ray continua and concave X-ray-to-γ-ray continua, α γX γ >0 and α XOX ?<?0, while FSRQs and LBLs have α γX γ ?<?0. The α XOX distribution of FSRQs and LBLs extends from negative to positive values. We suggest α γX γ ?>?0 and α XOX ?<?0 could be considered as a criterion for HBLs. Moreover, HBLs have narrow distribution of peak interval of $\log\nu_{\rm p}^{\rm ic}-\log\nu_{\rm p}^{\rm syn}$ , and FSRQs have significant anti-correlation between $\log\nu_{\rm p}^{\rm ic}-\log\nu_{\rm p}^{\rm syn}$ and $\log\nu_{\rm p}^{\rm syn}$ . This indicates that SSC model is responsible for high energy emission of HBLs, while EC for FSRQs. Our results also indicate that FSRQs with larger break energy of electrons have smaller bulk Lorentz factor of dissipation region. 相似文献
64.
现代水下技术在我国水运工程建设中的应用与前景 总被引:1,自引:0,他引:1
自本世纪80年代中期以来,世界水下工程技术随着各国科学水平的提高而得以迅速发展。本文从水下工程技术的专业范畴及特征着手,分析了现代水下技术在水运工程建设中的应用;介绍了国外现代水下技术的基本进展及趋势;评价了国内水下工程技术及装备水平,同时展示了我院近十年来在现代水下技术与装备和开发、应用方面所做的工作与实力;最后分析了国内水运工程建设发展对水下技术的挑战,以及发展我国现代水下技术装备开发研究所面 相似文献
65.
66.
青岛胶州湾地区重大工程建设项目设计的地质基础 总被引:3,自引:0,他引:3
本文以青岛胶州湾地区的基本地质条件为基础,分析研究了该地区地质基础对重大工程建设项目设计的影响,提出了青岛市重大工程项目设计的基本原则和对城市整体规划的具体建议。 相似文献
67.
Yuan Tian Zheng Wang Jian Li Zi-Huang Cao Wei Dai Shou-Lin Wei Yong-Heng Zhao 《天文和天体物理学研究(英文版)》2018,(5)
The Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) is the largest existing spectroscopic survey telescope, having 32 scientific charge-coupled-device(CCD) cameras for acquiring spectra. Stability and automation of the camera-control software are essential, but cannot be provided by the existing system. The Remote Telescope System 2 nd Version(RTS2) is an open-source and automatic observatory-control system. However, all previous RTS2 applications were developed for small telescopes. This paper focuses on implementation of an RTS2-based camera-control system for the 32 CCDs of LAMOST. A virtual camera module inherited from the RTS2 camera module is built as a device component working on the RTS2 framework. To improve the controllability and robustness, a virtualized layer is designed using the master-slave software paradigm, and the virtual camera module is mapped to the 32 real cameras of LAMOST. The new system is deployed in the actual environment and experimentally tested. Finally, multiple observations are conducted using this new RTS2-frameworkbased control system. The new camera-control system is found to satisfy the requirements for automatic camera control in LAMOST. This is the first time that RTS2 has been applied to a large telescope, and provides a referential solution for full RTS2 introduction to the LAMOST observatory control system. 相似文献
68.
本文研究了广义相对论效应和量子力学效应对中子量γ射线辐射的影响.通过选择磁偶极矩以及观察者视线与磁轴之间的夹角这两个观测量作为参量,我们数值计算了从中子星表面发射的、传播方向沿着磁场的光子的逃逸能量.我们得到,在磁偶极矩较小时,量子力学效应不重要,而广义相对论效应使逃逸能量显著降低;当磁偶极矩很大时,两个效应几乎相抵消,光子的逃逸能量几乎不受它们的影响.我们讨论这些结果在脉冲星γ射线谱上的意义. 相似文献
69.
70.
The stress–strain behaviour of a soil is crucial to the recognition of the mechanism of slope failure. Triaxial tests, composed of isotropically consolidated drained (ICD) and undrained compression (ICU) tests and anisotropically consolidated constant deviatoric stress path (CQD) tests, were carried out with the aim of investigating the stress–strain behaviour of loosely compacted volcanic-derived soils. The fact that the critical states are the same for ICU, ICD and CQD tests may show that the critical state is independent of the above three stress paths. The critical state line, as defined in critical state soil mechanics, is obtained from the e–log p′ and q–p′ plots based on the results of the above tests. The initial state of the consolidated specimens at initiation of failure may be classified as dilative or contractive in the light of the locations of the soil state relative to the critical state line. For contractional soils, the increased pore water pressure generated by rainfall infiltration leads to a contractive failure in a drained manner, giving rise to high excess pore water pressure. The excess pore water pressure caused by contraction cannot be dissipated instantly, resulting in a decrease in the shear resistance of the soil. The failure process is rapid. The failed soil mass is prone to flow after failure under the action of gravity due to its high moisture content and inflow of surface runoff and rainwater. For dilational soils, the increased pore water pressure resulting from infiltration leads to dilation, which reduces pore water pressure and thus increases the shear resistance of the soil. However, continued rainfall infiltration may be able to equilibrate the reduction in pore water pressure caused by dilation and, therefore, the dilation or displacement can continue. In Hong Kong, volcanic-derived soil is characterized by high permeability. Both the high permeability of volcanic-derived soil and a shallow failure surface make it possible for the reduction in pore pressure to equilibrate relatively quickly. Therefore, the failure is also rapid, at least for poorly compacted fill slopes. 相似文献