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971.
972.
973.
移相干涉测量技术是一种众所周知的非接触式的高精密测量方法,具有广泛的应用范围。环境振动是移相干涉仪测量误差的主要来源之一,国际上一些从事干涉测量的工作人员提出了许多抗振的方法,大体上分为主动技术和被动技术。主动抗振技术主要是系统自身探测振动并通过反馈回路对振动进行补偿,被动抗振技术则是通过各种技术措施尽量减小干涉仪对环境振动和气流影响的敏感度。从这两方面对干涉仪的抗振技术研究的进展做简单介绍,并介绍了作者所在课题组在这两个方面所进行的研究工作。 相似文献
974.
介绍了应用光电检测相关技术对模糊控制洗衣机的被洗衣物质料、衣物重量、脏污程度、脏污性质和洗涤剂量的快速准确检测方法及工作原理,通过相应的光电传感器实时检测出被洗衣物相关参数,以此作为模糊逻辑推理依据,来决定电动机的转速、洗涤水位和洗涤时间,经过实践验证它在节电、节水和洗净率等方面取得了良好的效果。 相似文献
975.
Multi-criteria decision analysis and environmental risk assessment for nanomaterials 总被引:1,自引:0,他引:1
Igor Linkov F. Kyle Satterstrom Jeffery Steevens Elizabeth Ferguson Richard C. Pleus 《Journal of nanoparticle research》2007,9(4):543-554
Nanotechnology is a broad and complex discipline that holds great promise for innovations that can benefit mankind. Yet, one
must not overlook the wide array of factors involved in managing nanomaterial development, ranging from the technical specifications
of the material to possible adverse effects in humans. Other opportunities to evaluate benefits and risks are inherent in
environmental health and safety (EHS) issues related to nanotechnology. However, there is currently no structured approach
for making justifiable and transparent decisions with explicit trade-offs between the many factors that need to be taken into
account. While many possible decision-making approaches exist, we believe that multi-criteria decision analysis (MCDA) is
a powerful and scientifically sound decision analytical framework for nanomaterial risk assessment and management. This paper
combines state-of-the-art research in MCDA methods applicable to nanotechnology with a hypothetical case study for nanomaterial
management. The example shows how MCDA application can balance societal benefits against unintended side effects and risks,
and how it can also bring together multiple lines of evidence to estimate the likely toxicity and risk of nanomaterials given
limited information on physical and chemical properties. The essential contribution of MCDA is to link this performance information
with decision criteria and weightings elicited from scientists and managers, allowing visualization and quantification of
the trade-offs involved in the decision-making process. 相似文献
976.
978.
Y. Caglar S. Ilican M. Caglar 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,58(3):251-256
It has recently been shown that growth of a multilayer
structure with one or more delta-layers at high temperature leads to
spreading and asymmetrization of the dopant distribution [see, for
example, E.F.J. Schubert, Vac. Sci. Technol. A. 8, 2980 (1990), A.M. Nazmul, S. Sugahara, M. Tanaka, J. Crystal Growth 251, 303 (2003); R.C. Newman, M.J. Ashwin, M.R. Fahy, L. Hart, S.N. Holmes, C. Roberts, X. Zhang, Phys. Rev. B 54, 8769 (1996); E.F. Schubert, J.M. Kuo, R.F. Kopf, H.S. Luftman, L.C. Hopkins, N.J. Sauer, J. Appl. Phys. 67, 1969 (1990); P.M. Zagwijn, J.F. van der Veen, E. Vlieg, A.H. Reader, D.J. Gravesteijn, J. Appl. Phys. 78, 4933 (1995); W.S. Hobson, S.J. Pearton, E.F. Schubert, G. Cabaniss, Appl. Phys. Lett. 55, 1546 (1989); Delta Doping of Semiconductors, edited by E.F. Schubert (Cambridge University Press, Cambridge, 1996); Yu.N. Drozdov, N.B. Baidus', B.N. Zvonkov, M.N. Drozdov,
O.I. Khrykin, V.I. Shashkin, Semiconductors 37, 194 (2003); E. Skuras, A.R. Long, B. Vogele, M.C. Holland, C.R. Stanley, E.A. Johnson, M. van der Burgt, H. Yaguchi, J.
Singleton, Phys. Rev. B 59, 10712 (1999); G. Li, C. Jagadish, Solid-State Electronics 41, 1207 (1997)]. In this
work analytical and numerical analysis of dopant dynamics in a
delta-doped area of a multilayer structure has been accomplished
using Fick's second law. Some reasons for asymmetrization of a
delta-dopant distribution are illustrated. The spreading of a
delta-layer has been estimated using example materials of a
multilayer structure, a delta-layer and an overlayer. 相似文献
979.
J. Jakubowicz K. Smardz L. Smardz 《Physica E: Low-dimensional Systems and Nanostructures》2007,38(1-2):139
In this study, we have proposed the powder technology as new method for preparation of bulk porous silicon. Formation of porous silicon by high-energy ball milling followed by pressing and sintering was studied by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy (XPS). A crystalline wafer with (1 1 1) orientation was extensively ball milled up to 72 h leading to a decrease in average crystallite size up to 15 nm. The most significant reduction of crystallite size was observed after milling process for about 24 h. The nanopowders were then pressed into pellets at a pressure up to 400 MPa and sintered at 1173 K for 60 min in a high purity argon atmosphere. Results showed that after sintering the material became porous with uniform porosity in whole volume, independently of the sinter size. It is not possible to prepare such porous materials using the conventional electrochemical etching, where the porous structure depth usually does not exceed tens of micrometers. Core-level XPS studies showed very good agreement between peak positions of the sintered porous silicon and in-situ prepared polycrystalline 20 nm-Si thin film or single-crystalline Si (1 1 1) wafer. Furthermore, the valence band spectra measured for sintered samples are broader compared to those measured for the Si (1 1 1) wafer or polycrystalline Si thin film. On the other hand, the shape and broadening of the valence bands measured for the sintered samples are in very good agreement with those reported for electrochemically prepared porous silicon. 相似文献
980.
XiaoFang Zhu ZhongHai Yang BaoQing Zeng 《International Journal of Infrared and Millimeter Waves》2004,25(5):837-843
Recent development of MEMS technologies has provided a set of methods for mass production of three-dimensional micro-scale structures and have opened the door to new and exciting possibilities in vacuum electronics devices. These micro-fabricated vacuum electronic devices are popular for the advantages of small volume, low cost, good performance, etc. In this article, Cold characteristics of a miniature coupled cavity slow-wave structure are simulated and discussed by using 3-D electromagnetic software MAFIA. The results show that this miniature structure can work at near 1.3 THz with high interaction impedance about 20 ohm and can be expected to be a promising THz radiation source. 相似文献