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51.
《Mendeleev Communications》2022,32(5):576-578
Novel highly soluble palladium-based complexes with ferrocenecarboxylic acid of general formula [Pd(lut)2(FcCOO)2] (lut is 2,6-or 3,4-lutidines) were synthesized and structurally characterized by single-crystal X-ray diffraction. The catalytic oxidation of 1,2-diphenyl-acetylene with these complexes gave dibenzo[a,e]pentalene derivative along with other products. 相似文献
52.
Jun-Rui Lyu Shao-Yi Wu Yu-Jing Hong Hao Wu Hui-Ning Dong 《Magnetic resonance in chemistry : MRC》2022,60(3):398-406
In this work, the g factors, d–d transition band, local distortion, and their concentration dependences for impurity V4+ in 20Li2O–20PbO–45B2O3–(15 − x)P2O5:V2O5 (0 ≤ x ≤ 2.5 mol%) glasses are theoretically investigated by using perturbation formulas of g factors for a tetragonally compressed octahedral 3d1 cluster. In the light of the cubic polynomial concentration functions for cubic field parameter Dq, covalency factor N, and relative tetragonal compression ratio ρ, the calculated concentration dependences of d–d transition band and g factors for V4+ show good agreement with the experimental data. With increasing x, N (≈0.7682–0.8165) displays the monotonously increasing trend, whereas ρ (≈6.5–4.2%) and Dq (≈1504.9–1481.1 cm−1) exhibit the decreasing tendencies. The above concentration dependences can be ascribed to the modifications of the V4+–O2− bonding and orbital admixtures around the impurity V4+ due to the effects of V2O5 doping on the stability of the glass network, the strength of local crystal fields, and the electron cloud distribution. 相似文献
53.
Feng Cheng Shuqi Wu Wenwei Zheng Shengqun Su Takumi Nakanishi Wenhuang Xu Pritam Sadhukhan Hibiki Sejima Shimon Ikenaga Kaoru Yamamoto Kaige Gao Shinji Kanegawa Prof. Osamu Sato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(59):e202202161
The crystallization of a complex having electron transfer properties in a polar space group can induce the polarization switching of a crystal in a specific direction, which is attractive for the development of sensors, memory devices, and capacitors. Unfortunately, the probability of crystallization in a polar space group is usually low. Noticing that enantiopure compounds crystallize in Sohncke space groups, this paper reports a strategy for the molecular design of non-ferroelectric polarization switching crystals based on the use of intramolecular electron transfer and chirality. In addition, this paper describes the synthesis of a mononuclear valence tautomeric (VT) cobalt complex bearing an enantiopure ligand. The introduction of enantiomer enables the crystallization of the complex in the polar space group (P21). The polarization of the crystals along the b-axis direction is not canceled out and the VT transition is accompanied by a change in the macroscopic polarization of the polar crystal. Polarization switching via electron transfer is realized at around room temperature. 相似文献
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55.
Dr. Linda Iffland-Mühlhaus Dr. Beatrice Battistella Dr. Daniel Siegmund Prof. Dr. Kallol Ray Prof. Dr. Ulf-Peter Apfel 《欧洲无机化学杂志》2023,26(30):e202300418
Cobalt complexes are extensively studied as bioinspired models for non-heme oxygenases as they facilitate both the stabilization and characterization of metal-oxygen intermediates. As an analog to the well-known Co(cyclam) complex Co{N4} (cyclam=1,4,8,11-tetraazacyclotetradecane), the CoII complex Co{i-N4} with the isomeric isocyclam ligand (isocyclam=1,4,7,11-tetraazacyclotetradecane) was synthesized and characterized. Despite the identical N4 donor set of both complexes, Co{i-N4} enables the 2e−/2H+ reduction of O2 with a lower overpotential (ηeff of 385 mV vs. 540 mV for Co{N4} ), albeit with a diminished turnover frequency. Characterization of the intermediates formed upon O2 activation of Co{i-N4} reveals a structurally identified stable μ-peroxo CoIII dimer as the main product. A superoxo CoIII species is also formed as a minor product, as indicated by EPR spectroscopy. In further reactivity studies, the electrophilicity of these in situ generated Co−O2 species was demonstrated by the oxidation of the O−H bond of TEMPO−H (2,2,6,6-tetramethylpiperidin-1-ol) via a H atom abstraction process. Unlike the known Co(cyclam), Co{i-N4} can be employed in oxygen atom transfer reactions oxidizing triphenylphosphine to the corresponding phosphine oxide highlighting the impact of geometrical modifications of the ligand while preserving the ring size and donor atom set on the reactivity of biomimetic oxygen activating complexes. 相似文献
56.
分别在EDTA,甘氨酸(Gly)和木质素磺酸钠(Ls)存在下,以硼氢化钠为还原剂,将Pd2+还原为Pd纳米颗粒并负载在多壁碳纳米管(MWCNT)表面。采用扫描电镜(SEM),透射电镜(TEM)和X射线衍射(XRD)对纳米Pd催化剂的形貌和微结构进行了表征。结果表明:EDTA存在时,所形成的Pd纳米颗粒(Pd-EDTA/MWCNT)的粒径更小,在MWCNT上的分散度更高。采用循环伏安(CV)和计时伏安技术(CA),研究了催化剂在碱性环境中对乙醇的电催化活性。在碱性溶液中对乙醇氧化的电化学研究表明:在Pd-EDTA/MWCNT催化剂上,乙醇氧化反应的起始电位较低,电流密度最大,电子传递阻力较小,反应速率较大,并且对乙醇氧化的电催化活性保持稳定。 相似文献
57.
58.
设计合成了一种新的C3对称性含膦三足体衍生物N',N',N'-三(亚磷酸三乙酯)缩氨三乙酸(L)及其Eu(Ⅲ)配合物.用1H NMR、13C NMR、红外光谱、元素分析、差热-热重及紫外光谱对其组成和结构进行分析和表征.结果表明,三足体衍生物与稀土苦味酸盐(Eu(pic)3·6H2O)形成了1:1配合物Eu(pic)3L.综合运用紫外-可见吸收光谱法、荧光光谱法和循环伏安法研究了Eu(pic)3L与小牛胸腺DNA之间的结合模式,结果表明,配合物Eu(pic)3L与DNA之间以嵌插形式发生相互作用.将该配合物作为杂交探针,对其在DNA电化学传感器方面的应用进行了探讨.结果发现,该配合物在修饰单链DNA的电极检测作用下,无明显的电化学信号响应,而当将其用于检测杂交双链DNA时,出现了明显信号,并且该配合物的DNA传感器对互补序列、错配序列及非互补序列都有良好的选择作用. 相似文献
59.
Magnetic Relaxation in Single‐Electron Single‐Ion Cerium(III) Magnets: Insights from Ab Initio Calculations 下载免费PDF全文
Saurabh Kumar Singh Tulika Gupta Dr. Liviu Ungur Prof. Dr. Gopalan Rajaraman 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(39):13812-13819
Detailed ab initio calculations were performed on two structurally different cerium(III) single‐molecule magnets (SMMs) to probe the origin of magnetic anisotropy and to understand the mechanism of magnetic relaxations. The complexes [CeIII{ZnII(L)}2(MeOH)]BPh4 ( 1 ) and [Li(dme)3][CeIII(cot′′)2] ( 1 ; L=N,N,O,O‐tetradentate Schiff base ligand; 2 ; DME=dimethoxyethane, COT′′=1,4‐bis(trimethylsilyl)cyclooctatetraenyldianion), which are reported to be zero‐field and field‐induced SMMs with effective barrier heights of 21.2 and 30 K respectively, were chosen as examples. CASSCF+RASSI/SINGLE_ANISO calculations unequivocally suggest that mJ|±5/2〉 and |±1/2〉 are the ground states for complexes 1 and 2 , respectively. The origin of these differences is rooted back to the nature of the ligand field and the symmetry around the cerium(III) ions. Ab initio magnetisation blockade barriers constructed for complexes 1 and 2 expose a contrasting energy‐level pattern with significant quantum tunnelling of magnetisation between the ground state Kramers doublet in complex 2 . Calculations performed on several model complexes stress the need for a suitable ligand environment and high symmetry around the cerium(III) ions to obtain a large effective barrier. 相似文献
60.
Behnaz Afzalian Joel T. Mague Maryam Mohamadi S. Yousef Ebrahimipour Behjat Pour amiri Esmat Tavakolinejad Kermani 《催化学报》2015,(7):1101-1108
Three complexes containing 2-pyrazinecarboxylate (pzca–), including [Ni(pzca)2(H2O)2], [Co(pzca)2(H2O)2], and [Cu(pzca)2(H2O)2], have been synthesized and characterized using physico-chemical and spectroscopic methods. Furthermore, the structure of each complex was determined by single-crystal X-ray diffraction. All three complexes have an octahedral geometry, where the metal ion chelated by two carboxylate oxygens, two nitrogen atoms belonging to pyrazinic acid molecules, and two oxygen atoms of two water molecules. The catalytic activities of these complex-es were also investigated in the green synthesis of 2H-indazolo[2,1-b]phthalazine-triones by the reaction of hydrazine hydrate with an arylaldehyde, phthalic anhydride, and dimedone in acetic acid. 相似文献