全文获取类型
收费全文 | 228篇 |
免费 | 7篇 |
国内免费 | 54篇 |
专业分类
化学 | 178篇 |
晶体学 | 3篇 |
力学 | 10篇 |
综合类 | 1篇 |
数学 | 41篇 |
物理学 | 56篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2018年 | 1篇 |
2014年 | 2篇 |
2013年 | 4篇 |
2012年 | 6篇 |
2011年 | 28篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 3篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 22篇 |
2004年 | 47篇 |
2003年 | 16篇 |
2002年 | 17篇 |
2001年 | 14篇 |
2000年 | 5篇 |
1999年 | 12篇 |
1998年 | 9篇 |
1997年 | 10篇 |
1996年 | 11篇 |
1995年 | 9篇 |
1994年 | 3篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 3篇 |
排序方式: 共有289条查询结果,搜索用时 15 毫秒
81.
QinFenSHI XiaoMeiWANG KeJunPAN WanLiJIANG DiJiangWEN XinBoWANG 《中国化学快报》2004,15(3):375-378
Three new naphthaline-type chromophores end-capped with different (p-substituted amino) styryl groups on the both sides (named as BPASN, BHMASN and BMASN) have been synthesized. Under excitation of 380nm, strong green light-emitting locating at 517nm with the fluorescence quantum yield of 0.88 in CH2Cl2 has been obtained.In the presence of β-cyclodextrin (β-CD), strong blue-emitting at 456nm in DMF was also recorded. 相似文献
82.
ZHAI WenGuang School of Mathematical Sciences Sh ong Normal University Jinan China 《中国科学A辑(英文版)》2009,(5)
In this paper we study the mean square of the error term in the Weyl’s law of an irrational (2l + 1)-dimensional Heisenberg manifold. An asymptotic formula is established. 相似文献
83.
本文研究了Waring-Goldbach问题(k=2)与Piatetski-Shapiro素数定理的混合问题,从而进一步深化了华罗庚教授的经典结果. 相似文献
84.
催化剂对煤着火特性的影响 Ⅱ.不同催化剂对煤催化着火的影响 总被引:10,自引:2,他引:8
通过测定煤的着火点研究了不同催化剂对大同烟煤和晋城无烟煤的催化着火的影响。结果表明,催化剂化学组成是决定催化作用大小的一个重要的因素,具有同一碱金属离子,不同阴离子的催化剂酸性越强,催化作用越弱,其催化活性顺序为OH~->CO_3~(2-)>Cl~->SO_4~(2-);具有同一阴离子,不同碱金属或碱土金属阳离子的催化作用可用“电子转移学说”来解释,其催化作用的大小,随相应的碱金属,碱土金属的第一电离能的减少而增加。 相似文献
85.
Jinan Rao Xiaolei Wen Jing Leng Jin Wang Gang Zou Qijin Zhang 《Applied Physics A: Materials Science & Processing》2012,109(3):621-626
We developed a novel temperature and pH dual-responsive supramolecular system in which the aggregation and disaggregation of polydiacetylene/silver (PDA/Ag) hybrid nanocrystals can be mediated by environmentally responsive threading and dethreading processes of polypseudorotaxane. The PDA/Ag hybrid nanocrystals provide a nonlinear optical (NLO) property. The host?Cguest interaction between poly(ethylene glycol) (PEG) and cyclodextrin (CD) cavities on the surface of the hybrid nanocrystals causes the PDA/Ag hybrid nanocrystals to be sufficiently close to each other for providing an enhanced surface plasmon resonance and a corresponding NLO effect. NLO switching of the colloidal materials can be easily realized by varying temperature and pH. The facile preparation procedures and their response to the surrounding media render these novel hybrid colloidal materials potential candidates for applications in sensors, catalysis and optical/electronic devices. 相似文献
86.
87.
条形空腔分集药包若干设计问题的研究 总被引:1,自引:1,他引:1
本文讨论了条形空腔药包的分集原则、间断长度、药量计算和最小空腔比的确定,以及条形空腔药包的地震效应等,它们都是条形空腔药包设计中必须解决的重要课题。文中对建立的计算公式列举了若干算例,证明与爆后的实际情况或小型试验比较吻合。 相似文献
88.
Jianzhong Chen Jinan Wang Weiliang Zhu Guohui Li 《Journal of computer-aided molecular design》2013,27(11):965-974
Molecular dynamics (MD) simulations followed by principal component analysis were performed to study the conformational change of MDM2 induced by p53 and two inhibitor (P4 and MI63a) bindings. The results show that the hydrophobic cleft of MDM2 is very flexible and adaptive to different structural binding partners. The cleft tends to become wider and more stable as MDM2 binds to the three binding partners, while unbound MDM2 shows a narrower and pretty flexible cleft, which agrees with recent experimental data and theoretical studies. It was also found that the binding of P4 and p53 stabilizes the motion of the loop L2 linking the helix α2 and β strand (β3), but the presence of MI63a makes the motion of L2 disordered. In addition, the binding free energies of the three partners to MDM2 were calculated using molecular mechanics generalized Born surface area to explain the binding modes of these three partners to MDM2. This study will be helpful not only for better understanding the functional, concerted motion of MDM2, but also for the rational design of potent anticancer drugs targeting the p53–MDM2 interaction. 相似文献
89.
MA JiaSai LI DongMei ZHAI YaXin & ZHAO Peng School of Physics Sh ong University Jinan China 《中国科学:物理学 力学 天文学(英文版)》2011,(8)
We propose a novel molecular junction with single-walled carbon nanotubes as electrodes bridged by a benzene molecule, in which the electrodes are saturated by different terminations (C-, H- and N-). It is found that the different terminations at the carbon nanotube ends strongly affect the electronic transport properties of the junction. The current-voltage (I-V) curve of the N-terminated carbon nanotube junction shows a more striking nonlinear feature than that of the C- and H-terminated junctions at smal... 相似文献
90.
贾广岩 《数学年刊A辑(中文版)》2007,(5)
考虑一类一维倒向随机微分方程(BSDE),其系数关于y满足左Lipschitz条件(可能是不连续的),关于z满足Lipschitz条件.在这样的条件下,证明了BSDE的解是存在的,并且得到了相应的比较定理. 相似文献