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951.
La0.67Ca0.33MnO3 and La0.67Ca0.33Mn0.96Fe0.04O3单晶的磁性和磁电阻特性。由于缺少晶粒间界,磁场对于自旋涨落的抑制作用更加明显,所以单晶中的磁电阻率比多晶的提高了两个数量级。通过Fe的掺杂,在40×105A/m的磁场下,磁电阻率从3400%进一步提高到了17600%。通过对居里温度以上电阻率的小极化子模型拟和的结果,我们看到随着Fe的掺杂,激活能被提高。磁极化子激活能的增大可以更加局域电子,这可能是在Fe掺杂单晶中本征磁电阻率进一步提高的主要原因。 相似文献
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Cover Picture: Mechanochromism and Mechanical‐Force‐Triggered Cross‐Linking from a Single Reactive Moiety Incorporated into Polymer Chains (Angew. Chem. Int. Ed. 9/2016) 下载免费PDF全文
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The use of matrix coating assisted by an electric field (MCAEF) to enhance mass spectrometric imaging of human prostate cancer biomarkers 下载免费PDF全文
Xiaodong Wang Jun Han Darryl B. Hardie Juncong Yang Christoph H. Borchers 《Journal of mass spectrometry : JMS》2016,51(1):86-95
In this work, we combined a newly developed matrix coating technique – matrix coating assisted by an electric field (MCAEF) and matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) to enhance the imaging of peptides and proteins in tissue specimens of human prostate cancer. MCAEF increased the signal‐to‐noise ratios of the detected proteins by a factor of 2 to 5, and 232 signals were detected within the m/z 3500–37500 mass range on a time‐of‐flight mass spectrometer and with the sinapinic acid MALDI matrix. Among these species, three proteins (S100‐A9, S100‐A10, and S100‐A12) were only observed in the cancerous cell region and 14 proteins, including a fragment of mitogen‐activated protein kinase/extracellular signal‐regulated kinase kinase kinase 2, a fragment of cAMP‐regulated phosphoprotein 19, 3 apolipoproteins (C‐I, A‐I, and A‐II), 2 S100 proteins (A6 and A8), β‐microseminoprotein, tumor protein D52, α‐1‐acid glycoprotein 1, heat shock protein β‐1, prostate‐specific antigen, and 2 unidentified large peptides at m/z 5002.2 and 6704.2, showed significantly differential distributions at the p < 0.05 (t‐test) level between the cancerous and the noncancerous regions of the tissue. Among these 17 species, the distributions of apolipoprotein C‐I, S100‐A6, and S100‐A8 were verified by immunohistological staining. In summary, this study resulted in the imaging of the largest group of proteins in prostate cancer tissues by MALDI‐MS reported thus far, and is the first to show a correlation between S100 proteins and prostate cancer in a MS imaging study. The successful imaging of the three proteins only found in the cancerous tissues, as well as those showing differential expressions demonstrated the potential of MCAEF‐MALDI/MS for the in situ detection of potential cancer biomarkers. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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The linear conjugate gradient method is an optimal method for convex quadratic minimization due to the Krylov subspace minimization property. The proposition of limited-memory BFGS method and Barzilai-Borwein gradient method, however, heavily restricted the use of conjugate gradient method for large-scale nonlinear optimization. This is, to the great extent, due to the requirement of a relatively exact line search at each iteration and the loss of conjugacy property of the search directions in various occasions. On the contrary, the limited-memory BFGS method and the Barzilai-Bowein gradient method share the so-called asymptotical one stepsize per line-search property, namely, the trial stepsize in the method will asymptotically be accepted by the line search when the iteration is close to the solution. This paper will focus on the analysis of the subspace minimization conjugate gradient method by Yuan and Stoer (1995). Specifically, if choosing the parameter in the method by combining the Barzilai-Borwein idea, we will be able to provide some efficient Barzilai-Borwein conjugate gradient (BBCG) methods. The initial numerical experiments show that one of the variants, BBCG3, is specially efficient among many others without line searches. This variant of the BBCG method might enjoy the asymptotical one stepsize per line-search property and become a strong candidate for large-scale nonlinear optimization. 相似文献
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为了快速诊断国产声波测井仪或其短节的工作状态是否正常,设计了可与仪器或短节相匹配的总线测试接口电路。针对国产声波类测井仪器的所用总线,设计了Tool control bus(TCB)、High local bus(HLB)、Tool model bus(TMB)、Controller area network(CAN)等总线测试接口。其中TCB、HLB、TMB总线接口在FPGA芯片EP2C20Q240C8控制下实现,软件采用模块化的结构设计;CAN总线接口由单片机C8051F500控制实现。利用了设计的接口电路板,仿真实现了TMB总线的从节点功能,可测试仪器主控短节的工作状态。 相似文献
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溶液中无机盐离子的定向流动会产生微弱的电压信号,通过检测电压信号可以计算离子的浓度、植物根系吸收离子的速度,进而获取植物的生理信息。对植物动态离子流信号检测系统进行设计,采用STM32F103ZET6作为主控芯片,利用极低偏置电流放大芯片和高共模抑制比差分放大芯片,给出了信号放大、滤波处理和数据采集电路,对系统噪声来源进行分析,提出了降低噪声的方法,并通过STM32进行A/D转换,把转换数据传输到上位机。该设计实现了植物动态离子流信号的检测,得到了离子在溶液中的流速。 相似文献