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991.
将壳聚糖与氯乙酸反应,通过控制反应条件制备了取代度为0.71的O-羧甲基壳聚糖,将改性后的O-羧甲基壳聚糖与多聚磷酸钠反应,制备了粒径分布在370-710nm的O-羧甲基壳聚糖纳米微粒,透射电镜观察表明该微粒呈球状,平均粒径为450nm.在此基础上研究了O-羧甲基壳聚糖纳米微粒对工业电镀镍废水Ni~(2+)吸附性能,考察了溶液pH、Ni~(2+)起始浓度、平衡吸附时间、粒径等因素的影响,结果表明:O-羧甲基壳聚糖微粒最佳吸附条件是Ni~(2+)溶液pH为8.0、Ni~(2+)溶液起始浓度为33.28mg/ml、平衡吸附时间为0.5h、粒径较小的O-羧甲基壳聚糖纳米微粒对Ni~(2+)的吸附量要大于粒径较大的吸附量. 相似文献
992.
首先通过电聚合方法在玻碳电极表面制备了聚(3-甲基噻吩)(P3MT)修饰膜,然后在一定电位下将DNA分子电沉积到P3MT表面,制备了DNA/(P3MT)复合膜修饰玻碳电极.研究了8-羟基-2’-脱氧鸟嘌呤核苷(8-OH-dG)在该复合膜修饰电极上的伏安行为以及扫描速度、pH值和尿酸对其伏安行为和检测的影响.实验结果表明,该复合膜修饰电极结合了P3MT和DNA两者的优点,使8-OH-dG在复合膜修饰电极上的电化学行为明显改善,而且具有很好的重现性和稳定性.在0.1mol/LpH7.0的磷酸盐缓冲溶液(PBS)中,8-OH-dG的氧化峰电流与其浓度在0.28~4.2μmol/L和4.2~19.6μmol/L两个范围内成良好的线性关系,检出限为56nmol/L(S/N=3).该研究可以为制备HPLC或毛细管电泳电化学检测器检测8-OH—dG打下一定的基础,因此在检测尿样中8-OH-dG的研究方面具有潜在的应用价值. 相似文献
993.
The fluorescence properties of a series of rare earth (Re3+ = Eu3+, Tb3+) polymeric complexes (PEK-Re3+-HLs) using three high-Tg novel carboxyl-containing polyaryletherketones (PEK) as macromolecular ligands and small molecules (HL) such as 1,10-phenanthroline (Phen), dibenzoylmethane (DBM) and 8-hydroxyquinoline (HQ) as co-ligands were investigated by means of fluorescence excitation and emission spectroscopy as well as fluorescence lifetime measurement methods. Among them, PEK-1-Re3+-Phens, in which the Re3+ ions were coordinated simultaneously with Phen and PEK-1 containing both carboxyl and bulky isopropyl groups on the polymer backbone, exhibited strong fluorescence intensities, long lifetimes, and good film-formation properties. The smooth films of PEK-1-Eu3+-Phen and PEK-1-Tb3+-Phen, cast from their DMF solutions, could emit bright red and green light under the UV lamp of 365 nm, respectively, which characteristics are of great significance for their potential applications in the large area display material fields. The excellent fluorescence properties of complexes in this study were attributed to the synergistic effects of PEK-1 ligand and Phen co-ligand. Especially, the rigid twisted structure and the bulky isopropyl substituents on PEK-1 backbone forced the coordinated rare earth ion moieties apart, and thus the probability of non-radiative decay rate of Re3+ ions at the excited levels were decreased to a large extent. 相似文献
994.
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997.
M. A. Bastrakov A. M. Starosotnikov A. Kh. Shakhnes S. A. Shevelev 《Russian Chemical Bulletin》2008,57(7):1539-1542
Transformation of the amino group in 7-amino-1-methyl-4,6-dinitro-2-phenylindole afforded a number of new 7-R-4,6-dinitroindoles
and a first representative of a novel tricyclic heteroaromatic system of [1,2,5]oxadiazolo[4,3-g]indole.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1508–1511, July, 2008. 相似文献
998.
Using Stuttgart/Dresden effective core potentials MWB28, MWB60, and GTO valence basis sets (8s7p6d)/[6s5p3d], (8s7p6d)/[6s5p3d]
for Zr and Hf atoms and 6-311++G(3df,3pd) basis set for C, H, O, and Ti atoms, tight convergence criteria geometry optimizations
and harmonic frequency calculations are performed at B3LYP and B3LYP/IEF-PCM levels of theory so as to model the gas phase
and argon matrix infrared spectra of the tetrahedral molecules R2MH2 (R = D(H), CH3, OH; M = Ti, Zr, Hf). Influence of the transition metal and/or substituent group on the symmetric and asymmetric stretching
frequencies of the MH2 fragment of the R2MH2 molecules is investigated at both the levels of theory. The modelling of the argon matrix effect improves the agreement between
the calculated frequencies and the experimental ones. The calculated argon matrix to gas phase frequency shifts is compared
reasonably to the experimental argon to neon matrix shifts. 相似文献
999.
WANG Ling ZHANG Xiao-xia YUAN Hong-ming CHEN Yan DONG Zhong-ping PANG Guang-sheng FENG Shou-hua 《高等学校化学研究》2008,24(1):1-3
Cu2O particles with different morphologies and scales were prepared sonochemically on the solid-liquid interface of CuCl and water, by adjusting the reaction factors. The products were characterized by powder X-ray diffraction(XRD) and scanning electron microscopy(SEM). The formation and morphology of Cu2O crystals were influenced by high-intensity ultrasound, reaction temperature, and addition of CuCl. The results indicate that micrometer Cu2O was crystallized in cubic and octahedral shapes, whereas, nanometer Cu2O was not produced in well-shaped crystals. 相似文献
1000.
Borjana V. Donkova Katja I. Milenova Dimitar R. Mehandjiev 《Central European Journal of Chemistry》2008,6(1):115-124
The precursors with a low manganese content ≤ 0.07% Mn were synthesized by spontaneous crystallization from Zn2+, Mn2+ and C2O4
2−-containing solutions. The initial ratio Zn2+:C2O4
2− = 1:1 and 1:2 influences the morphology and prevailing orientations of the crystallites in the oxalate samples. The presence
of such small Mn content in the samples does not change the morphology or size of the crystals. The ZnO and Mn/ZnO oxides
with manganese content from 0.51×10−2 to 15.1×10−2 Wt % are obtained after thermal decomposition of the oxalates. The oxides preserved the morphology of the precursors. The
catalytic tests show that the pure ZnO has a poor activity for CO oxidation reaction. Its doping with Mn promotes the catalytic
activity (up from twice to five times) in spite of the very low contents of the dopants. The observed increase of the activity
depends on both dopant concentration and Zn2+:C2O4
2− ratio, probably due to the different mechanism of the manganese inclusion and different morphology of the oxides. The catalysts
of the 1:2 series are more active in CO oxidation reaction.
相似文献