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691.
用532nm的Nd:YAG激光直接溅射铬/磷粉末混合物样品产生铬/磷团簇,并用串级飞行时间质谱仪研究了二元团簇的组份分布及紫外激光光解规律.实验表明,铬/磷极易形成富磷的二元团簇离子,CrPm+团簇离子系列表现出明显的奇偶振荡效应,且CrP4+,CrnP8+(n=1~4),Cr4P9+,Cr5P11+,Cr6P12+和Cr8P14+等为质谱中丰度较大的离子,不随样品组成的变化而变化,光解时主要以失去中性P2和P4的方式进行解离,尝试对其电子结构进行推测.并与铬/硫二元团簇的形成和光解结果作简单对比. 相似文献
692.
《Comptes Rendus de l''Academie des Sciences Series IIB Mechanics Physics Astronomy》2001,4(11):805-808
We present a time evolution of 1H spin-lattice relaxation rates in the laboratory (1/T1) and in the rotating (1/T1ρ) frame of a synthetic cement paste. The typical results found for both rates allow us to follow the main hydration stages of the cement paste and the refinement of its microporosity. In particular the texturation of the porosity and the structuration of the surface of the material are evidenced on two model cement pastes. An interpretation in terms of fractal size distribution is considered as well as the effect of the curing temperature. 相似文献
693.
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695.
Dong Yang Ming-zhi Su Hui-jun Zheng Zhi Zhao Gang Li Xiang-tao Kong Hua Xie Hong-jun Fan Wei-qing Zhang Ling Jiang 《化学物理学报(中文版)》2019,32(2):223-228
The mass-selected infrared photodissociation (IRPD) spectroscopy was utilized to investigate the interactions of cationic cobalt with carbon dioxide molecules. Quantum chemical calculations were performed on the [Co(CO2)n]+ clusters to identify the structures of the low-lying isomers and to assign the observed spectral features. All the [Co(CO2)n]+(n=2-6) clusters studied here show resonances near the CO2 asymmetric stretch of free CO2 molecule. Experimental and calculated results indicate that the CO2 molecules are weakly bound to the Co+ cations in an end-on con guration via a charge-quadrupole electrostatic interaction. The present IRPD spectra of [Co(CO2)n]+ clusters have been compared to those of Ar-tagged species ([Co(CO2)n]+-Ar), which would provide insights into the tagging effect of rare gas on the weakly-bounded clusters. 相似文献
696.
The photoelectron imagings of LaO-, CeO-, PrO-, and NdO- at 1064 nm are reported. The well resolved photoelectron spectra allow the electron a±nities to be determined as 0.99(1) eV for LaO, 1.00(1) eV for CeO, 1.00(1) eV for PrO, and 1.01(1) eV for NdO, respectively. Density functional calculations and natural atomic orbital analyses show that the 4f electrons tend to be localized and suffer little from the charge states of the molecules. The photodetached electron mainly originates from the 6s orbital of the metals. The ligand field theory with the δ=2 assumption is still an effective method to analyze the ground states of the neutral and anionic lanthanide monoxides. 相似文献
697.
The dynamics of the Cl+SiH4 reaction has been studied using the universal crossed molecular beam method. Angular resolved time-of-flight spectra have been measured for the channelSiH3Cl+H. Product angular distributions as well as energy distributions in the center-of-mass frame were determined for the channel. Experimental results show that the SiH3Clproduct is mainly backward scattered relative to the Cl atom beam direction, suggestingthat the channel takes place via a typical SN2 type reaction mechanism. 相似文献
698.
Rapid internal conversion in a symmetric molecule LD 700 studied by means of femtosecond fluorescence depletion 下载免费PDF全文
The rapid internal conversion dynamics at room temperature is
determined by using the femtosecond time-resolved fluorescence
depletion measurements of a complex solvated molecule of LD 700
(rhodamine 700) combined with steady-state absorption and
fluorescence spectroscopy, as well as quantum chemical calculation.
The molecule is excited by a 50fs laser pulse at 400nm which
directly populated the highly excited singlet state, the rapid
internal conversions (ICs) are observed, which leads to the
directional changes of the emission transition moment following
photoexcitation to the highly excited singlet state S5 of LD
700. 相似文献
699.
在半经典近似下将动力学李代数方法和中间绘景结合应用于原子-双原子分子(非谐振子)共线碰撞中的平动-振动传能的研究。在群参量的一级近似下求解群参量的运动方程,进而确定时间演化算符。并以散射体系H2+He为例,计算了H2分子的振动跃迁几率,计算结果与精确量子力学计算结果符合得较好。 相似文献
700.