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951.
An HPLC method has been developed for the separation of valdecoxib and a degradation product consisting of α and β-N-lactosyl sulfonamide, i.e. α and β anomers (SC-77852). Best results were achieved with a Chromolith Performance RP-18e column (100 mm × 4.6 mm), macropore size 2 μm, mesopore size 13 nm, with an eluent of methanol:water containing a 1% solution of TEA (36:64 v/v), pH 7.4 (adjusted with 85% orthophosphoric acid), at 22 °C. Detection was at 220 nm. The method was validated for its selectivity, linearity, precision (repeatability) and robustness. Quantitation and detection limits were determined for both valdecoxib and SC-77852. Method robustness was further evaluated by performing 23 full factorial design experiments. The final step, optimisation of the variables, was performed using response surface design. The validated method was used for assay of valdecoxib and SC-77852 in Bextra® film-coated tablets. 相似文献
952.
Z. Mra 《国际流体数值方法杂志》1993,17(11):995-1002
A method of optimal design of Francis turbine tongue and wicket gate angle for given spiral casing is proposed. The potential flow in the doubly connected domain is decomposed into basic and circulation flows. The intensity of circulation is then calculated by the least-squares method minimizing the error function equal to the sum of squares of differences between given and calculated circumferential velocities in the outflow boundary nodes. It is shown that the error function has a sharp minimum, which qualifies the proposed method as well defined. For given numerical example, the variations in the outflow velocity angles are much smaller for optimal than for already used non-optimal design. A finite element method is used, with originally developed pre- and post-processor and frontal solver suited for personal computers. 相似文献
953.
Narjès Bellamine-Ben Saoud Gloria Mark 《Computational & Mathematical Organization Theory》2007,13(2):113-146
In this paper, we investigate how complexity theory can benefit collaboration by applying an agent-based computer simulation
approach to a new form of synchronous real-time collaborative engineering design. Fieldwork was conducted with a space mission
design team during their actual design sessions, to collect data on their group conversations, team interdependencies, and
error monitoring and recovery practices. Based on the fieldwork analysis, an agent-based simulator was constructed. The simulation
shows how error recovery and monitoring is affected by the number of small group, or sidebar, conversations, and consequent
noise in the room environment. This simulation shows that it is possible to create a virtual environment with cooperating
agents interacting in a dynamic environment. This simulation approach is useful for identifying the best scenarios and eliminating
potential catastrophic combinations of parameters and values, where error recovery and workload in collaborative engineering
design could be significantly impacted. This approach is also useful for defining strategies for integrating solutions into
organizations.
Narjès Bellamine-Ben Saoud is an Associate Professor at the University of Tunis and Researcher at RIADI-GDL Laboratory, Tunisia. After Computer Science
engineering diploma (1993) of the ENSEEIHT of Toulouse, France, she received her PhD (1996), on groupware design applied to
the study of cooperation within a space project, from the University of Toulouse I, France. Her main research interests concern
studying complex systems particularly by modeling and simulating collaborative and socio-technical systems; developing Computer
Supported Collaborative Learning in tunisian primary schools; and Software Engineering. Her current reserach projects include
modeling and simulation of emergency rescue activities for large-scale accidents, modeling of epidemics and study of malaria,
simulation of collabration artifacts.
Gloria Mark is an Associate Professor in the Department of Informatics, University of California, Irvine. Dr. Mark received her Ph.D.
in Psychology from Columbia University in 1991. Prior to UCI, she was a Research Scientist at the GMD, in Bonn, Germany, a
visiting research scientist at the Boeing Company, and a research scientist at the Electronic Data Systems Center for Advanced
Research. Dr. Mark’s research focuses on the design and evaluation of collaborative systems. Her current projects include
studying worklife in the network-centric organization, multi-tasking of information workers, nomad workers, and a work in
a large-scale medical collaboratory. Dr. Mark is widely published in the fields of CSCW and HCI, is currently the program
co-chair for the ACM CSCW’06 conference and is on the editorial board of Computer Supported Cooperative Work: The Journal
of Collaborative Computing, and e-Service Qu@rterly. 相似文献
954.
机械制造系统生产水平的综合评价 总被引:1,自引:0,他引:1
运用数理统计和模糊数学的某些概念,本文提出了一种评价机械制造系统生产水平的新方法,机械制造系统可以用模糊变换器来描述,这个模糊变换器比较客观和全面地揭示机械制造系统的内在规律。借助这个模糊变换器来综合评价机械制造系统具有很大的理论和实践价值,并为机械制造系统论奠定新的基础。无心磨削系统的实验研究证明了本文基本观点的正确性。 相似文献
955.
含有三个非球面的卡塞格林系统光学设计 总被引:7,自引:0,他引:7
介绍了一种含三个非球面的卡塞格林系统的设计思想,给出了一个设计结果。焦距2.8m,F/5.6,视场3.2°,主镜、次镜均为6次方非球面,场镜含一4次方非球面,成像质量接近衍射极限,畸变也得到了校正。 相似文献
956.
现有的两类一元理论离心泵叶轮水力设计方法存在试凑性工作量大或盖板形状不为简单曲线的缺陷。本文提出了符合一元理论的离心泵叶轮轴面流道过流断面的一种新的分布规律,并给出了按照此分布规律计算叶轮轴面流道过流面积的计算方法和公式。将其与传统的两类设计方法做了比较。 相似文献
957.
We consider the class of saturated main effect plans for the 2k factorial. With these saturated designs, the overall mean and all main effects can be unbiasedly estimated provided that there are no interactions. However, there is no way to estimate the error variance with such designs. Because of this and other reasons, we like to add some additional runs to the set of (k+1) runs in the D‐optimal design in this class. Our goals here are: (1) to search for s additional runs so that the resulting design based on (k+s+1) runs yields a D‐optimal design in the class of augmented designs; (2) to classify all the runs into equivalent classes so that the runs in the same equivalent class give us the same value of the determinant of the information matrix. This allows us to trade runs for runs if this becomes necessary; (3) to obtain upper bounds for determinant of the information matrices of augmented designs. In this article we shall address these approaches and present some new results. © 2002 Wiley Periodicals, Inc. J Combin Designs 11: 51–77, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jcd.10026 相似文献
958.
Philip Birch Gongde Li Frederic Claret-Tournier Rupert Young Chris Chatwin 《Optics and Lasers in Engineering》2004,41(6):919-926
Two optical lenses are used to compose a surface position measuring system. A measurand is positioned near the front focal point of the first lens. At the output end of the other lens, a beam splitter is used to split the beam into two paths. One photodetector is positioned before the focal point of the lens in one path and another after the focal point in the other so that the intensities falling onto the two detectors can be adjusted to be equal when the first lens is in focus. This device provides a compact and high-accuracy surface sensor. In this paper, the design and experimental study of the sensor system is described. It is shown that such a sensor embodiment can lead to a resolution of 1 μm. 相似文献
959.
960.
在二值单稳态触发器设计的基础上,提出了四值单稳态触发器的设计方案.经过PSPICE模拟,所设计的电路具有正确的逻辑功能,并能由此方法推广到基值更高的单稳态触发器的设计.与二值单稳态触发器相比,四值单稳态触发器具有更强的功能. 相似文献