全文获取类型
收费全文 | 240篇 |
免费 | 1篇 |
国内免费 | 4篇 |
专业分类
化学 | 35篇 |
力学 | 2篇 |
综合类 | 2篇 |
数学 | 158篇 |
物理学 | 48篇 |
出版年
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 46 毫秒
91.
Keivan Navi Akbar DoostareganMohammad Hossein Moaiyeri Omid Hashemipour 《Fuzzy Sets and Systems》2011,185(1):111-124
A new hardware-friendly mathematical method for realizing low-complexity universal Adder cells as well as its efficient hardware implementations is proposed in this paper. This method can be used in binary logic, Multiple-Valued Logic (MVL) and specifically digital fuzzy systems. The proposed mathematical method can be implemented in both voltage and current modes. The voltage-mode hardware implementation is very simple and is based on input capacitors and MVL or analog inverters and buffers. In addition, the current-mode hardware implementation leads to simple and efficient structures for digital fuzzy systems. Simulations are carried out for ternary logic as well as for digital fuzzy logic with high precision by using 180 nm standard CMOS technology and at 1.8 V supply voltage. Simulation results demonstrate that the proposed designs have excellent functionality and are very suitable for implementing MVL and fuzzy arithmetic circuits. 相似文献
92.
为实现金属离子检测和分子水平的信息处理, 合成了一类新型的含有功能配位基团的螺吡喃衍生物(SP1-SP4). 研究发现: 在没有UV光照的条件下, 金属离子可以促进螺吡喃(SP2和SP4)开环并形成稳定可逆的络合物(MC-Mn+). 紫外-可见吸收光谱研究表明, 在UV光照前加入不同的金属离子会引起SP2 和SP4 的光学性质的特征变化, 因此提供了一种简易的通过裸眼就能辨别金属离子的比色方法. 荧光光谱研究表明, 这类化合物能够高灵敏高选择性地检测锌离子. 此外, 基于吸收光谱和荧光光谱的变化, 这类螺吡喃衍生物可以用于构建组合的逻辑门, 执行分子水平的信息处理, 从而展现了其在化学或环境传感和未来的分子计算机领域的潜在应用前景. 相似文献
93.
在模糊逻辑系统中提出了广义有效推理;根据积分真度的性质,证明了广义有效推理的积分真度递减定理,从而在模糊逻辑系统中实现了根据推理前提的真度计算推理结论的真度;最后,把真度递减定理与利用斐波那契数列对推理结论真度的推算结果进行了对比,说明了真度递减定理的优越性. 相似文献
94.
95.
Yan SenLin 《Communications in Nonlinear Science & Numerical Simulation》2012,17(7):2896-2904
A physical model of the fundamental configuration of two mutually coupled semiconductor lasers is presented for logic-gate applications, and the principles of optoelectronic logic computing based on chaotic synchronization or chaotic de-synchronization are defined. Two laser diodes were coupled via injection of each into the opposite laser and became chaotic; our analysis showed that the oscillation derives from chaotic fluctuations after a progression from stability to period-doubling by varying the coupling factor, delay time or detuning. Chaotic synchronization is achieved between the two lasers through the coupling, where we found chaotic and quasi-periodic synchronization regions. Based on the chaotic synchronization system, three optoelectronic logic gates can be implemented by modulating the laser diode current to synchronize or de-synchronize the two chaotic states. Finally, we studied the effects of resynchronization time on logic gate function in a practical implementation of the system. Numerical results show the validity and feasibility of the method. 相似文献
96.
Lanlan Li Jian Wu Jifang Qiu Bingbing Wu Kun Xu Xiaobin Hong Yan Li Jintong Lin 《Optics Communications》2010,283(19):3608-3612
We demonstrate a reconfigurable all-optical logic gate for NRZ-PolSK signal based on FWM in a highly nonlinear fiber at 10 Gb/s. Half subtracter, XOR, AB?, āB or XNOR, AND, and NOR logic gates can be implemented simultaneously. The input power for the HNLF is optimized to be as low as about 15.2 dBm and the high Q factors above 8 dB for eye diagrams are achieved. Experimental results show Q factors of AB?, āB, AND, and NOR were higher than those of XOR, and XNOR. Error-free operation is achieved experimentally for 10 Gb/s 27-1 pseudorandom bit sequence (PRBS) data. Power penalties for the logic gate are less than 3 dB. Simulation analysis about the wavelength characteristic for all logic gates is given and it predicts that the reconfigurable logic gate can realize error-free operation when the wavelength separation is less than 5 nm. 相似文献
97.
A new diarylethene with ethylimidazo[2,1-b]thiazole-6-hydrazide unit was synthesized, and its photochromic and fluorescent behaviors have been systematically investigated by the stimulation of lights and metal ions in methanol. This new diarylethene exhibited high selectivity and sensitivity toward Al3+ and Zn2+. The addition of Al3+ and Zn2+ displayed excellent colorimetric response behaviour with the concomitant color change from colorless to yellow, which could be easily observed by the naked eye. Upon addition of Al3+, the fluorescence intensity was enhanced by 180–fold and the emission peak of 1O–Al3+ blue-shifted by 15?nm accompanied with a color change from colorless to bright blue. In contrast, when stimulated with Zn2+, its fluorescence intensity was enhanced by 35–fold and the emission peak of 1O–Zn2+ red-shifted by 16?nm with an evident color change from black to bright green. The LOD for Al3+ and Zn2+ were determined to be 2.97?×?10?9?mol?L?1 and 5.98?×?10?9?mol?L?1, respectively. Moreover, a logic circuit was constructed with the fluorescence intensity as the output signal responding to the light and chemical species as the inputs. 相似文献
98.
99.
本文提出了克服PLA固定容量的限制,扩展逻辑综合能力的两种技术:一是在改用带二位译码器PLA的情况下,减少函数乘积项的算法;二是将逻辑函数修改技术用于PLA的逻辑综合技术。 相似文献
100.