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91.
本文用穆斯堡尔效应和X射线衍射等方法对不同添加物的SrFe_(12)~-O_(19)铁氧体永磁材料进行了研究。结果表明,可以观察到材料中的不同添加物与铁原子核的超精细相互作用的差异,以及它们对磁性能的不同影响。加入适量的SrSO_4和H_3BO_3作为添加物,有利于磁性能的改善。 相似文献
92.
Kiyoshi Endo Yosiyuki Kondo 《Journal of polymer science. Part A, Polymer chemistry》2008,46(8):2858-2863
Polymerization of 2‐pentene with [ArN?C(An)C(An)·NAr)NiBr2 (Ar?2,6‐iPr2C6H3)] ( 1‐Ni) /M‐MAO catalyst was investigated. A reactivity between trans‐2‐pentene and cis‐2‐pentene on the polymerization was quite different, and trans‐2‐pentene polymerized with 1‐Ni /M‐MAO catalyst to give a high molecular weight polymer. On the other hand, the polymerization of cis‐2‐butene with 1‐Ni /M‐MAO catalyst did not give any polymeric products. In the polymerization of mixture of trans‐ and cis‐2‐pentene with 1‐Ni /M‐MAO catalyst, the Mn of the polymer increased with an increase of the polymer yields. However, the relationship between polymer yield and the Mn of the polymer did not give a strict straight line, and the Mw/Mn also increased with increasing polymer yield. This suggests that side reactions were induced during the polymerization. The structures of the polymer obtained from the polymerization of 2‐ pentene with 1‐Ni /M‐MAO catalyst consists of ? CH2? CH2? CH(CH2CH3)? , ? CH2? CH2? CH2? CH(CH3)? , ? CH2? CH(CH2CH2CH3)? , and methylene sequence ? (CH2)n? (n ≥ 5) units, which is related to the chain walking mechanism. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2858–2863, 2008 相似文献
93.
Nathan A. Lacher Qian Wang Rachel K. Roberts Heidi J. Holovics Serdar Aykent Michael R. Schlittler Melissa R. Thompson Charles W. Demarest 《Electrophoresis》2010,31(3):448-458
A CGE method for monitoring the disulfide isomer distribution characteristic of IgG2 MAbs is presented. Disulfide heterogeneity of MAbs has been studied using various chromatographic and electrophoretic methods. Although CGE operates using a different selectivity mechanism from that of sorption chromatographic techniques, similar trends are present in the data, which allow the CGE method to be used as a complementary method for studying disulfide isomer distribution. This article focuses on the optimization of a capillary‐based gel electrophoresis method that can be used to support antibody development including bioprocess optimization, antibody characterization, release, and formulation stability assessment. 相似文献
94.
Abstract A pair of CuII coordination isomers [Cu(pmt)2] · 4H2O (1) and {[Cu(pmt)2] · 2H2O}
n
(2) [Hpmt = 2-(2-pyridylmethylamino) ethanesulfonic acid] have been prepared by reaction of the same proportion CuCl2 · 2H2O and Hpmt but with different experimental methods in water–methanol mixed solution, and were characterized by X-ray diffraction,
elemental analysis, IR spectrum. X-ray analysis indicates that complex (1) is a mononuclear complex in which two deprotonated pmt ligands coordinate in a facial tridentate arrangement about the CuII atom. While complex (2) is a coordination polymer, in which four N atoms of pmt ligands coordinate to one CuII atom but its sulfonate O atoms bond to adjacent CuII atom. Thus 12-membered rings (–Cu–N–C–C–S–O–)2 are obtained between two neighbouring CuII atoms and they connect one another to form this new polymer. Crystal data: [Cu(pmt)2] · 4H2O (1), Mr = 566.10, monoclinic, P2
1/c, a = 9.1950(8) ?, b = 11.5093(10) ?, c = 11.2304(10) ?, β = 105.5550(10)°, Z = 2, V = 1144.96(17) ?3, R
1
= 0.0407, wR
2
= 0.1242 [I > 2σ (I)]; {[Cu(pmt)2] · 2H2O}
n
(2), Mr = 530.07, triclinic, P-1, a = 7.6165(19) ?, b = 8.806(2) ?, c = 9.592(4) ?, α = 104.933(4)°, β = 106.732(4)°, γ = 109.503(3)°, Z = 1, V = 534.2(3) ?3, R
1 = 0.0470, wR
2 = 0.1082 [I > 2σ(I)].
Index Abstract A pair of CuII coordination isomers [Cu(pmt)2] · 4H2O (1) and {[Cu(pmt)2] · 2H2O}
n
(2) [Hpmt = 2-(2-pyridylmethylamino) ethanesulfonic acid] have been prepared by reaction of the same proportion CuCl2 · 2H2O and Hpmt but with different experimental methods in water–methanol mixed solution.
相似文献
95.
Jan C. A. Boeyens Leanne M. Cook Tak-ho Ngoi David H. Reid 《Journal of chemical crystallography》1996,26(3):215-218
The crystal structure of two isomeric oximes, C11N10N2OS have been studied by X-ray diffraction. The open-chain thiocyanato derivative is somewhat'less dense and crystallizes with the orthorhombic space group Pbcn;a,b,c=18.718(1), 10.601(3), 11.528(1) Å,Z=8. The heterocyclic isomer occurs as pseudo-orthorhombic (Cmma)twinned crystals of space group P21/n, a, b, c, =12.11(1), 7.46(1), 12.12(1) Å, 100.09(1)o,Z=4. Twinning occurs as a result of the near-equality of the monoclinica andc cell constants. 相似文献
96.
Sergio Peris Bartosz Tylkowski Joan Carles Ronda Ricard Garcia‐Valls José Antonio Reina Marta Giamberini 《Journal of polymer science. Part A, Polymer chemistry》2009,47(20):5426-5436
Two new polyethers, bearing azobenzene moiety in the side chain, were synthesized in excellent yields by means of anionic polymerization of 4‐glycidyloxyazobenzene and 4‐cyano‐4′‐glycidyloxyazobenzene (leading to azo‐P1 and azo‐P2 polymers, respectively) with the system polyiminophosphazene base t‐Bu‐P4/3,5‐di‐tert‐butylphenol as initiator. The polymers were characterized with respect to their molecular weights, structure, and calorimetric features. The polyether bearing cyanoazobenzene group in the side chain was found to exhibit nematic phase up to 200 °C. E–Z isomerization of both polymers in tetrahydrofuran solution, after irradiating with UV light at 364 nm for 15 min, was investigated by means of UV–visible absorption spectroscopy. In the case of glycidylic monomers as well as the resulting polymers, E–Z isomerization was also investigated by means of 1H NMR, by direct irradiation in the NMR probe in deuterated 1,1,2,2‐tetrachloroethane solution. By this technique, in the case of 4‐cyano‐4′‐glycidyloxyazobenzene, it was found that irradiation led to a photostationary state corresponding to an amount of Z isomer equal to 25%. For azo‐P1 polymer, Z–E or “reverse” isomerization was investigated at 60, 70, or 80 °C directly in the NMR probe; as expected, the process followed a first‐order rate law. The kinetic constants as well as the activation energy for the process were determined in this temperature range. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5426–5436, 2009 相似文献
97.
We demonstrate the ability of all-trans DPEN as a suitable ligand for transition metals by DFT computation [B3LYP/6-311+G(2d,p) and BP86 level]. The iron complex Fe(DPEN) is a unique topological isomer of ferrocene. 相似文献
98.
毛细管区带电泳是一种分离单克隆本异型体(species)的高效分析技术,为此,采用氟代烃键合毛细管柱,研究了氟代烃表面活性剂浓度,缓冲溶液的组成,pH值等条件对单克隆抗体迁移性能的影响。结果表明:对于单克隆抗体的定性分析区带毛细管电泳比排阻色谱具有更高的分离能力,本文的实验条件对单克隆抗体生产中的质量控制具有潜在的应用前景。 相似文献
99.
Shenzhen Cong Yunqi Zhou Chenglian Luo Caixia Wang Prof. Jixiao Wang Prof. Zhi Wang Prof. Xinlei Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(15):e202319894
Membrane-based separation has the merit of low carbon footprint. In this study, the pore size of metal–organic framework (MOF) membranes is rationally designed for discriminating various pairs of hydrocarbon isomers. Specifically, Zr-MOF UiO-66 (UiO stands for University of Oslo) membranes are developed for separating p/o-xylene due to their proper pore size. For n-hexane/2-methylpentane separation, the functional groups and proportion of the ligands in UiO-66 are gradually adjusted to effectively regulate the pore size, and UiO-66-33Br membranes are constructed. In addition, relying on the utilization of ligands with shorter length, MOF-801 membranes with smaller pore size are fabricated for n/i-butane separation. 相似文献
100.
使用密度泛函方法(B3LYP)和6-311 G(3df,3pd)基组计算得到了HPO3体系的9个异构体与11个过渡态,并用内禀反应坐标理论验证了异构体的异构化过程.结果表明,在HPO3体系中,只有热力学最稳定的平面型异构体HOFO2(E1),(cis,cis)构象的HOOPO(E3)和立体的具有Cs对称性的异构体HP(O)O2(E7)具有较高的动力学稳定性,理论预测结果与实验一致.另外2个立体的HOFO2连接方式的异构体(E2和E4)由于解离为HO(Ⅱ) OPO(^2A1)的解离能较低,因此不能稳定存在。 相似文献