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991.
Li Jun Li Qi Feng Chen Lai Bo Yu Zhao Heng Zhong Jun Feng Hao Cheng Hong Xing Kong Jian Ling Wu 《中国化学快报》2007,18(4):431-434
A flow injection irreversible biamperometric method for the determination of chlorogenic acid is described.The proposedmethod is based on the electrochemical oxidation of chlorogenic acid at pretreated platinum electrode and the reduction ofpermanganate at another electrode to form an irreversible biamperometric detection system.Under the external potential difference(△E)of 0 V,in the 0.05 mol/L sulfuric acid,chlorogenic acid can be determined over the range 0.8-120 mg/L with a samplemeasurement frequency of 80 samples/h.The detection limit is 0.18 mg/L.The proposed method exhibits the satisfactoryreproducibility with a relative standard derivation(R.S.D.)of 2.21%for 19 successive determinations of 40 mg/L. 相似文献
992.
993.
The subsolidus phase relations in the B-rich part of the ternary system, Na2O-SrO-B2O3, are investigated by the powder X-ray diffraction method. Four ternary compounds: NaSrBO3, NaSr4B3O9, Na3SrB5O10 and NaSrB5O9 were found in it, the two lasts are new. NaSrB5O9 crystallizes in the monoclinic space group P21/c, with the lattice parameters a=6.4963(1) Å, b=13.9703(2) Å, c=8.0515(1) Å, β=106.900(1)°. Na3SrB5O9 is also monoclinic, space group C2, a=7.290(1) Å, b=13.442(2) Å, c=9.792(1) Å, β=109.60(1). NaSrB5O9 is isostructural with another pentaborate NaCaB5O9, and its structure was refined by Rietveld method based on the structural model of NaCaB5O9. The fundamental building units are [B5O9]3− anionic groups, forming complex thick anionic sheets, extending parallel to the ac plane. The Na and Sr atoms are all eight-coordinated with O atoms, forming trigonal dodecahedra. The [NaO8] polyhedra are distributed between the B-O sheets, while the [SrO8] polyhedra located in the sheets and connect with each other by edges to form infinite chains along the c-axis. 相似文献
994.
Ling-Yan Kong Xi-Hong Lu Hiroyuki Kawaguchi Hui-Fang Zhu 《Journal of solid state chemistry》2007,180(1):331-338
Three novel coordination polymers [Cd3(L)2(μ-Br)(μ-Cl)Br3Cl] (1), [Cd3(L)2(μ-Cl)2Cl4] (2) and [Cd(L)Cl]2[CdCl4]·H2O (3) were obtained by reactions of an imidazole-containing tripodal ligand N1-(2-aminoethyl)-N1-(2-imidazolethyl)-ethane-1,2-diamine (L) with Cd(II) salts. Their structures were determined by X-ray crystallography. Crystal data for 1, monoclinic system, P21/c, a=7.752(4) Å, b=31.70(2) Å, c=14.012(7) Å, β=109.439(7)°, V=3247(3) Å3, Z=4. 2, monoclinic system, P21/c, a=7.6564(15) Å, b=31.433(6) Å, c=13.925(3) Å, β=109.89(3)°, V=3151.1(11) Å3, Z=4. 3, orthorhombic system, Pbcn, a=22.950(2) Å, b=8.435(7) Å, c=17.360(2) Å, V=3360.3(51) Å3, Z=4. Complexes 1 and 2 have similar one-dimensional (1D) branched-chain structure while complex 3 features a 1D zigzag cationic chain with [CdCl4]2− serving as counter anion. The photoluminescent measurements reveal that all the complexes exhibit blue fluorescence at room temperature in the solid state. 相似文献
995.
996.
997.
A simple and rapid micellar electrokinetic chromatography (MEKC) method with UV detection was developed for the simultaneous separation and determination of all-trans- and 13-cis-retinoic acids in rabbit serum by on-line sweeping concentration technique. The serum sample was simply deproteinized and centrifuged. Various parameters affecting sample enrichment and separation were systematically investigated. Under optimal conditions, the analytes could be well separated within 17min, and the relative standard deviations (RSD) of migration times and peak areas were less than 3.4%. Compared with the conventional MEKC injection method, the 18- and 19-fold improvements in sensitivity were achieved, respectively. The proposed method has been successfully applied to the determination of all-trans- and 13-cis-retinoic acids in serum samples from rabbits and could be feasible for the further pharmacokinetics study of all-trans-retinoic acid. 相似文献
998.
Efficient Visible‐Light‐Driven Carbon Dioxide Reduction by a Single‐Atom Implanted Metal–Organic Framework 下载免费PDF全文
Dr. Huabin Zhang Dr. Jing Wei Dr. Juncai Dong Dr. Guigao Liu Li Shi Dr. Pengfei An Dr. Guixia Zhao Dr. Jintao Kong Dr. Xiaojun Wang Dr. Xianguang Meng Prof. Jing Zhang Prof. Jinhua Ye 《Angewandte Chemie (International ed. in English)》2016,55(46):14310-14314
Modular optimization of metal–organic frameworks (MOFs) was realized by incorporation of coordinatively unsaturated single atoms in a MOF matrix. The newly developed MOF can selectively capture and photoreduce CO2 with high efficiency under visible‐light irradiation. Mechanistic investigation reveals that the presence of single Co atoms in the MOF can greatly boost the electron–hole separation efficiency in porphyrin units. Directional migration of photogenerated excitons from porphyrin to catalytic Co centers was witnessed, thereby achieving supply of long‐lived electrons for the reduction of CO2 molecules adsorbed on Co centers. As a direct result, porphyrin MOF comprising atomically dispersed catalytic centers exhibits significantly enhanced photocatalytic conversion of CO2, which is equivalent to a 3.13‐fold improvement in CO evolution rate (200.6 μmol g?1 h?1) and a 5.93‐fold enhancement in CH4 generation rate (36.67 μmol g?1 h?1) compared to the parent MOF. 相似文献
999.
Turn‐On Colorimetric Platform for Dual Activity Detection of Acid and Alkaline Phosphatase in Human Whole Blood 下载免费PDF全文
Dr. Qiong Hu Dr. Baojing Zhou Prof. Dr. Feng Li Prof. Dr. Jinming Kong Prof. Dr. Xueji Zhang 《化学:亚洲杂志》2016,11(21):3040-3045
The activity detection of acid phosphatase (ACP) and alkaline phosphatase (ALP) is of great importance to the diagnosis and prognosis of related diseases. In this work, we report for the first time a turn‐on colorimetric platform for the activity detection of ACP and ALP, by exploiting Cu(BCDS)22? (BCDS=bathocuproinedisulfonate) as the probe. The presence of ACP or ALP dephosphorylates the substrate ascorbic acid 2‐phosphate to produce ascorbic acid, which then reduces Cu(BCDS)22? into Cu(BCDS)23?, leading to a turn‐on spectral absorption at 484 nm and a dramatic color change of the solution from colorless to orange‐red. The underlying metal‐to‐ligand charge‐transfer mechanism has been demonstrated by quantum mechanical computations. This platform allows a rapid, sensitive readout of ACP and ALP activities within the dynamic range from 0 to 220 mU ml?1. In addition, it is highly immune to false‐positive results and also highly selective. More importantly, it is applicable in the presence of human serum and even whole blood samples. These results demonstrate that our platform holds great potential in clinical practices and in the point‐of‐care analysis. 相似文献
1000.