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241.
Lin‐Jian Zhu Jian Wang Tie‐Gang Reng Chun‐Yan Li Dong‐Cai Guo Can‐Cheng Guo 《Journal of Physical Organic Chemistry》2010,23(3):190-194
Six tetraphenylporphyrins (TRPPH2) with different horizontal substituents R (R = H, CH3, OH, F, Cl, Br) were synthesized, and the organic light‐emitting diode (OLED) devices with a general configuration of ITO/TPD/Alq3:2%TRPPH2/Alq3/Al were prepared. The substituted TRPPH2 was used as the host dopant, 4,4‐bis‐(m‐tolyphenylamino)biphenyl (TPD) was used as a hole‐transporting material, and aluminum tris(8‐quinolinolato) (Alq3) was used as an electron‐transporting material. The electroluminescent (EL) properties of these devices were studied to understand the light emitting properties of the substituted TRPPH2. Previous studies have found that the color emitted by the devices was dependent on the TRPPH2 dye concentration. The electronic effect of the horizontal substituents R of TRPPH2 influenced the turn‐on voltage, brightness, and power efficiency of the devices. Also, the electroluminescence performance of the porphyrin‐doped OLED devices depended on the effectual overlaps between the emission of electron‐transporting material and the absorption of the dopants. This means that it is possible to evaluate the electroluminescence performance of the porphyrin‐doped OLED devices based on the emission of electron‐transporting material and the absorption of the dopants. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
242.
本文利用金刚石对顶砧(DAC)和拉曼光谱技术,测量了四苯基卟啉J聚集体在13GPa内的高压拉曼光谱,根据各个拉曼谱带的频移-压强变化曲线得出在13GPa内Tpp J聚集体无相变发生,并且高波数(1010~1600cm-1)和低波数(230~330cm-1)区的斜率要远大于中等波数(380~1000cm-1)区,这表明对应于高波数和低波数区的化学键比中等波数区更具有易压缩性,并对体积的减小起着重要的作用。根据苯环ψ3C-C面内伸缩振动模式强度逐渐增强的现象提出了分子弹簧垫圈模型。此外,这种分子弹簧垫圈的劲度系数可以通过中位取代基团调控。 相似文献
243.
Elena Tarabukina Eugenia Fagadar-Cosma Corina Enache Natalia Zakharova Mihaela Birdeanu 《Journal of Macromolecular Science: Physics》2013,52(8):1092-1106
Molecular properties and aggregation behavior of a polysiloxane with grafted side chain groups consisting of asymmetrical hydroxy-functionalized porphyrin were studied in dilute solutions. In order to understand the mechanism of aggregation of the polymeric porphyrin derivatives, several analyses of chloroform solutions were performed permitting comparison of the data obtained by means of different techniques. Molar mass and hydrodynamic size of the macromolecules were obtained using the methods of analytical ultracentrifugation, isothermal translational diffusion, and viscometry. Long distance interactions between macromolecules in dilute solutions were detected with static light scattering. With increasing the concentration of the solutions, the electronic and fluorescence spectra bands assigned to generation of H and J aggregates became apparent. The organization of aggregates, which seemed to be favored by chloroform, was visualized by atomic force microscopy images that displayed sponge-like morphology, small triangular particles, characteristic of H aggregates, and nano or micro-structured ring geometries obtained by the side-by-side J-process, coexisting together. 相似文献
244.
Two extensive homologous series of H-shaped symmetrical dimers were synthesized and their thermotropic properties studied by differential scanning calorimetry and on a hot-stage of a polarizing microscope. These compounds consist of two mesogenic units of azoester interconnected through flexible spacers (n?=?4) resulting in the structure of ‘H-shaped’ dimeric compounds. The difference between the two series is in the structure of terminal substituents (–CH3 for series I and –OCH3 for series II) attached on the azoester mesogens at one terminus. All these compounds were found to be smectogenic. The effect of different terminal substituents on mesomorphism is discussed. The trans-azobenzene groups of the H-shaped dimeric compounds display a high-intensity π–π* transition at about 365?nm and a low-intensity π–π* transition at around 460?nm, therefore, photochromism can be achieved by the introduction of the azo linkage to the H-shaped dimeric compounds. 相似文献
245.
铝卟啉是一类土壤环境友好的金属卟啉,尽管早在1978年Inoue就已经发现它可以催化CO2和环氧丙烷的共聚反应,但是该催化体系一直面临催化活性低、聚合物相对分子质量低等难题。 本文通过改变铝卟啉催化剂配体中苯环上取代基的种类和位置,制备出中心金属电子环境差异化的铝卟啉,并以双三苯基膦氯化铵(PPNCl)为助催化剂,探讨其对CO2与环氧丙烷的共聚反应的催化行为。 结果表明,当铝卟啉中苯环上2,4位同时被Cl-取代后,在90 ℃和3 MPa压力下,转化频率(TOF)达到2672 h-1。 当利用离去能力较强的对甲苯磺酸基团(OTs-)作为铝卟啉的轴向配体,可以合成出数均相对分子质量达1.84×105的脂肪族聚碳酸酯。 相似文献
246.
Daria Larowska Dr. Aleksandra Wojcik Dr. Marta Mazurkiewicz-Pawlicka Dr. Artur Malolepszy Dr. Leszek Stobiński Prof. Bronislaw Marciniak Dr. Anna Lewandowska-Andralojc 《Chemphyschem》2019,20(8):1054-1066
Non-covalent nanohybrids composed of cationic 5,10,15,20-tetra(4-trimethylammoniophenyl)porphyrin tetra(p-toluenesulfonate) (TMAP) and the graphene oxide sheets were prepared under two pH values (6.2 vs. 1.8). The TMAP molecule was positively charged, regardless of the pH value during preparation. However, protonation of the imino nitrogens increased the overall charge of the porphyrin molecule from +4 to +6 (TMAP4+ and TMAP6+). It was found that at acidic pH, interaction of TMAP6+ with GO was largely suppressed. On the other hand, results of FTIR, Raman spectroscopy, thermogravimetric analysis, atomic force microscopy (AFM) and elemental analysis confirmed effective non-covalent functionalization of graphene oxide with cationic porphyrin at pH 6.2. The TMAP4+-GO hybrids exhibited well defined structure with a monolayer of TMAP4+ on the GO sheets as confirmed by AFM. Formation of the ground-state TMAP4+-GO complex in solution was monitored by the red-shift of the porphyrin Soret absorption band. This ground-state interaction between TMAP4+ and GO is responsible for the static quenching of the porphyrin emission. Fluorescence was not detected for the nanohybrid which indicated that a very fast deactivation process had to take place. Ultrafast time-resolved transient absorption spectroscopy clearly demonstrated the occurrence of electron transfer from the photoexcited TMAP4+ singlet state to GO sheets, as proven by the formation of a porphyrin radical cation. 相似文献
247.
In this paper we continue our consideration of closed-packed dimers on the kagome lattice. Using the Pfaffian approach we evaluate the correlation between dimers on two lattice edges. It is found that the correlation is extremely short-ranged in the case of symmetric dimers weights. Explicit expressions for the nonvanishing correlations are obtained for two dimers in the interior of a large lattice. We also describe a Grassmannian functional integral approach, and use it to evaluate the dimer generating function and correlation functions. 相似文献
248.
染料敏化太阳能电池光敏剂卟啉儿茶酚的密度泛函和含时密度泛函研究 总被引:1,自引:1,他引:0
用密度泛函理论的杂化密度泛函B3LYP方法研究了太阳能电池光敏荆5,10,15.三苯基-20-(3,4-二羟基苯)卟啉(卟啉儿荼酚,TPP-cat)的几何结构、电子结构、IR和Raman特性.用自然键轨道方法分析了电荷布居和成键性质.计算结果表明,最强的IR吸收峰位于1175.81 cm-1处,最强的Raman活性位于1587.18 cm-1处.采用含时密度泛函计算了TPP-cat在水溶液中的电子吸收谱,其Soret带和Q带均指认为π→π*跃迁,在大约354 cm-1处的跃迁与一个光诱导分子内电荷转移过程有关. 相似文献
249.
利用激子旋转扩散理论研究了一类低掺杂卟啉侧链聚合物中卟啉侧链基团的旋转对其发光动力学过程的影响.研究表明,卟啉侧链基团的旋转行为是导致激发态无辐射能量弛豫的重要途径.基团旋转越容易,能量弛豫速度越快,这可导致一个快速的荧光衰变动力学过程.在卟啉低掺杂浓度和聚合物分子链间距离较大的情况下,卟啉侧链基团的旋转成为影响荧光寿命和发光效率的主要因素.对实验测得的两种样品的荧光弛豫过程进行了拟合,理论结果与实验结果符合较好.
关键词:
激子旋转弛豫
瞬态荧光
卟啉侧链聚合物 相似文献
250.
Li-Hua Su Tian-Ze Li Yun-Bao Ma Chang-An Geng Xiao-Yan Huang Xin Zhang Zhen Gao Ji-Jun Chen 《中国化学》2022,40(1):104-114
Inspired by the intriguing structures and remarkable activities of sesquiterpenoid dimers,12 new sesquiterpenoid dimers,artematrovirenolides A—D(1—4)and artematrolides S—Z(8—12),were isolated from the EtOAc fraction of Artemisia atrovirens through a bioactivity-guided approach.Their structures were elucidated by comprehensive spectroscopic data and absolute configuration was assigned based on single crystal X-ray diffraction data and ECD calculations.Structurally,all compounds are presumably formed via[4+2]cycloaddition involving three connecting model.Compounds 1—4 are four novel hetero-dimeric[4+2]Diels-Alder adducts dimerized from a rotundane-type unit and a guaiane-type monomer,and compounds 5—12 are eight new homo-dimeric[4+2]adducts derived from two guaianolide moieties.A putative biosynthetic pathway for compounds 1—4 was also proposed.Compounds 4,6,7,and 10 demonstrated moderate cytotoxicity against HepG2,SMMC-7721,and Huh7 cell lines with IC50 values ranging from 9.3 to 62.3μmol/L.Interestingly,compounds 5 and 11 manifested cytotoxicity with IC50 values of 13.6 and 12.8(HepG2),18.5 and 13.1(SMMC-7721),and 16.5 and 19.4μmol/L(Huh7),respectively,which were equivalent to the positive control,sorafenib.This investigation suggests that compounds 5 and 11 might be considered as potent antihepatoma candidates and deserve further structural modification and mechanism study. 相似文献