首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   240篇
  免费   1篇
  国内免费   4篇
化学   35篇
力学   2篇
综合类   2篇
数学   158篇
物理学   48篇
  2023年   4篇
  2022年   3篇
  2021年   2篇
  2020年   6篇
  2019年   7篇
  2018年   9篇
  2017年   5篇
  2016年   4篇
  2015年   5篇
  2014年   6篇
  2013年   11篇
  2012年   16篇
  2011年   22篇
  2010年   13篇
  2009年   18篇
  2008年   13篇
  2007年   15篇
  2006年   17篇
  2005年   11篇
  2004年   8篇
  2003年   8篇
  2002年   7篇
  2001年   10篇
  2000年   4篇
  1999年   4篇
  1998年   2篇
  1996年   3篇
  1995年   3篇
  1994年   3篇
  1993年   1篇
  1991年   1篇
  1985年   1篇
  1982年   1篇
  1981年   1篇
  1970年   1篇
排序方式: 共有245条查询结果,搜索用时 187 毫秒
51.
不完全三值逻辑在语言表达上的相互比较   总被引:2,自引:0,他引:2  
深入讨论各种命题联结词含量不完全的三值逻辑的语言表达的能力,完全弄明白了三值系统L3,L3,B3,B3,K3,K3,MP的语言表达能力的等效或不等效关系,特别应当指出的一个结论是:中介命题逻辑MP作为一种命题联结词含量不完全的三值系统而言,它和其他命题联结含量不完全的三值逻辑L3,L3Δ,B3,B3Δ,K3,K3Δ的语言表达能力都不等效,从而也由此体现出MP的一种自身特色。  相似文献   
52.
借助于模糊逻辑连接词的灵敏度,定义了模糊推理系统的灵敏度,研究了几种常见的模糊推理系统的灵敏度,进一步估算了各种模糊推理机的灵敏度,并将模糊推理系统的灵敏度与模糊连接词灵敏度的关系用等式表示出来。  相似文献   
53.
In this paper, we establish a stronger version of Artemov's arithmetical completeness theorem of the Logic of Proofs LP0. Moreover, we prove a version of the uniform arithmetical completeness theorem of LP0.  相似文献   
54.
《Current Applied Physics》2020,20(12):1424-1428
In this work, electrical Joule heating (J-H) was employed for the first time to electrically isolate ZnO nanowire FETs array for one dimensional (1D) logic applications without any physical and electrical damages. The electrical properties of the isolated nanowire FETs were found to be superior to non-isolated FETs came from the neighboring gate effect. Finally, we investigated ZnO nanowire-based NOT, NAND, and NOR logic gates with the J-H nanowire isolation technique. The isolated logic gates clearly show much lower output voltage off level than the non-isolated circuits thus resulting in more accurate and reliable 1D electronic applications.  相似文献   
55.
The paper studies closure properties of classes of fuzzy structures defined by fuzzy implicational theories, i.e. theories whose formulas are implications between fuzzy identities. We present generalizations of results from the bivalent case. Namely, we characterize model classes of general implicational theories, finitary implicational theories, and Horn theories by means of closedness under suitable algebraic constructions.  相似文献   
56.
Based on the results of [11] this paper delivers uniform algorithms for deciding whether a finitely axiomatizable tense logic
  • has the finite model property,
  • is complete with respect to Kripke semantics,
  • is strongly complete with respect to Kripke semantics,
  • is d-persistent,
  • is r-persistent.
It is also proved that a tense logic is strongly complete iff the corresponding variety of bimodal algebras is complex, and that a tense logic is d-persistent iff it is complete and its Kripke frames form a first order definable class. From this we obtain many natural non-d-persistent tense logics whose corresponding varieties of bimodal algebras are complex. Mathematics Subject Classification: 03B45, 03B25.  相似文献   
57.
As a novel sensing system, N-(1-pyrenylmethyl) amide-appended calix[4]crown-5 (2) and crown-6 (3) have been newly synthesized. Judging from the fluorescence changes upon the addition of cations, 3 having crown-6 ring showed the Pb2+ ion selectivity over other cations tested regarding fluorescence quenching. Upon the Pb2+ ion coordination to two amide oxygen atoms with aid of crown ring, a reverse-photo-induced electron transfer (PET) occurs in such a way that electrons transfer from the pyrene groups to the electron deficient amide oxygen atoms to give a quenched fluorescence. By the addition of either HClO4 or triethylamine in the solution of 3, the fluorescence intensity decreased because of the reverse-PET from pyrene groups to protonated amide oxygen atoms and because of normal PET from the nitrogen anion formed by triethylamine to pyrene groups, respectively. For 3, NOR logic gate in which the strong fluorescence signal appears at 395 nm (output: 1) is operated only when neither of triethylamine nor Pb(ClO4)2 (inputs A and B) is added (A=B: 0). XNOR gate is also operated only when both of two inputs are added (triethylamine and HClO4, A=B: 1) or when neither of two inputs is added (A=B: 0). Then, for 3, new INHIBIT gate system was also designed using such combinational inputs as HClO4, Pb(ClO4)2 and triethylamine.  相似文献   
58.
采用苦参碱(Matrine, MT)和槐定碱(Sophoridine, SR)作为电活性药物分子探针, 考察了聚(N-异丙基)丙烯酰胺(PNIPAM)水凝胶薄膜的刺激响应特性; 并通过循环伏安(CV)法和扫描电子显微镜(SEM)研究了PNIPAM在不同外界刺激条件(如温度、 盐浓度和甲醇)下结构的改变. 在25 ℃时, 药物分子MT和SR在玻碳电极上产生较大的氧化峰电流, 随着温度升高至40 ℃, 药物分子探针的氧化峰电流逐渐减小. 考察了不同Na2SO4浓度和不同比例甲醇对PNIPAM水凝胶薄膜的影响, 发现MT和SR的氧化峰电流随着Na2SO4浓度(00.45 mol/L)和甲醇比例(040%)的升高而减小. 结果表明, MT和SR可作为分子探针研究PNIPAM水凝胶薄膜对环境的三重刺激响应性开关行为, 并可进一步构筑3-输入/2-输出的逻辑门系统.  相似文献   
59.
根据准相位匹配线性电光效应耦合波理论,基于单个周期性极化铌酸锂晶体,提出了外电场可控的电光复合与门、或门的逻辑计算方法.采用级联周期性极化铌酸锂晶体,探讨了外电场可控的电光复合逻辑异或门、半加法器、半减法器的逻辑计算方法.在外加电场分别为0.184KV/mm和0.368KV/mm条件下,分析了光波的波长、方位角和极角、晶体的温度对逻辑输出的影响.研究结果表明,基本逻辑门的逻辑计算能够成功实现,但其逻辑计算对光波波长、晶体温度、方位角和极化角非常敏感,这些参量轻微的变化会导致逻辑输出的改变.该方案可推广到更为复杂的基本逻辑门以及三个以上逻辑输入与输出的基本逻辑门中.  相似文献   
60.
We have developed several logic gates (OR, XOR, AND and NAND) made of superconducting Josephson junctions. The gates based of the flux cloning phenomenon and high speed of fluxons moving in Josephson junctions of different shapes. In a contrast with previous design the gates operates extremely fast since fluxons are moving with the speed close to the speed of light. We have demonstrated their operations and indicated several ways to made a more complicated logic elements which have at the same time a compact form.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号