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排序方式: 共有4125条查询结果,搜索用时 15 毫秒
941.
正作为长距离分布式侧面泵浦技术的典型代表,泵浦增益一体化复合功能激光光纤(Pump-gain integrated Functional Laser Fiber,PIFL-fiber)是包含单根增益光纤与多根泵浦光纤的多功能集成器件。基于倏逝波耦合效应巧妙地解决了超大泵浦功率注入的技术难题,已成为高功率光纤激光放大技术的主流技术方案之一。2018年2月,中国工程物理研究院激光聚变研究中心科研人员成功制备(8+1)型PIFL复合功能激光光 相似文献
942.
Preparation and Luminescence Properties of the Ternary Europium Complex Incorporated into an Inorganic/Polymer Matrix by a Sol-Gel Method 总被引:2,自引:0,他引:2
Fu Lianshe Zhang Hongjie Wang Shubin Meng Qingguo Yang Kuiyue Ni Jianzuan 《Journal of Sol-Gel Science and Technology》1999,15(1):49-55
Ternary europium complexes with thenoyltrifluoroacetone (TTA) and phenanthroline (phen) were incorporated into SiO2/polymer matrix by a sol-gel method. The gels exhibit the characteristic emission bands of europium ion. In addition, Eu3+ presents a longer fluorescence lifetime in gel than in the corresponding pure complex powder. Concentration effects on the luminescence intensity were investigated. The reasons that are responsible for above results are also discussed in the context. 相似文献
943.
Three cyanide-bridged dodecanuclear macrocyclic wheel-like complexes [Cr(bpmb)(CN)2]6[Mn(5-Brsalpn)]6·12H2O (1), [Co(bpmb)(CN)2]6[Mn(5-Brsalpn)]6·12H2O (2) and [Co(bpmb)(CN)2]6[Mn(5-Clsalpn)]6·24H2O·8CH3CN (3) [bpmb2−= 1,2-bis(pyridine-2-carboxamido)-4-methylbenzenate dianion; 5-Brsalpn2− = N,N′-propylenebis(5-bromosalicylideneaminato) dianion; 5-Clsalpn2− = N,N′-propylenebis(5-chlorosalicylideneaminato) dianion] have been synthesized and their crystal structures and magnetic properties
have been investigated. The three compounds are structurally isomorphous and consist of alternating Mn(III)-Schiff base cations
and [M(bpmb)(CN)2]− anions, generating cyanide-bridged nanosized dodecanuclear macrocyclic structures with an approximate diameter of 2 nm. The
study of the magnetic properties of complex 1 reveals an antiferromagnetic interaction between the Cr(III) and Mn(III) ions
through the cyanide bridges. A best-fit to the magnetic susceptibility of the complex leads to a magnetic coupling constant
of J
CrMn = −2.65(6) cm−1 on the basis of a one-dimensional alternating chain model with the Hamiltonian $
H = - J_{CrMn} \sum\limits_{i = 0}^N {S_i \cdot S_{i + 1} }
$
H = - J_{CrMn} \sum\limits_{i = 0}^N {S_i \cdot S_{i + 1} }
. 相似文献
944.
Preparation of poly(vinylphenylboronic acid) chain grafted poly(glycidylmethacrylate‐co‐ethylenedimethacrylate) beads for the selective enrichment of glycoprotein 下载免费PDF全文
Surface‐initiated atom transfer radical polymerization was successfully used to prepare 4‐vinylphenylboronic acid functionalized poly(glycidylmethacrylate‐co‐ethylenedimethacrylate) beads for the selective enrichment of glycoprotein from complex biological samples in this study. The modified bead surfaces were characterized using Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The sorption behaviors, including adsorption isotherms, incubation time, and pH effect, were investigated. The results demonstrated that the boronated beads have a high affinity for glycoprotein, which is due to the well‐defined boronic acid brushes on the beads surfaces. Furthermore, the polyvinylphenylboronic acid grafted poly(glycidylmethacrylate‐co‐ethylenedimethacrylate) beads were used to efficiently enrich and purify glycoprotein from real egg white samples and α‐fetoprotein from human serum samples. The mass spectrometry results demonstrated that the polyvinylphenylboronic acid grafted poly(glycidylmethacrylate‐co‐ethylenedimethacrylate) beads are a suitable material for the enrichment of glycosylated protein from complex biological samples. 相似文献
945.
Ni J He L Liu YM Cao Y He HY Fan KN 《Chemical communications (Cambridge, England)》2011,47(2):812-814
Supported gold nanoparticles (NPs), which are well-known epoxidation catalysts, were found to be exceptionally active for the selective deoxygenation of epoxides into alkenes using cheap and easily accessible CO and H(2)O as the reductant. 相似文献
946.
Experimental and simulation investigation of ion transfer in different sampling capillaries 下载免费PDF全文
Quan Yu Tao Jiang Kai Ni Xiang Qian Fei Tang Xiaohao Wang 《Journal of mass spectrometry : JMS》2015,50(12):1367-1373
Atmospheric pressure interfaces were a fundamental structure for transferring air generated ions into the vacuum manifold of a mass spectrometer. This work is devoted to the characterization of ion transfer in metal capillaries through both experimental and simulated investigations. The impact of capillary configurations on ion transmission efficiency was evaluated using an electrospray mass spectrometer with various bent capillaries as the transfer devices. In addition, a numerical model has been set up by coupling the SIMION 8.0 and the computational flow dynamics for simulation study of ion migration in the complex atmospheric system. The transfer efficiency was found to be highly affected by the variation in electric field and the capillary geometry, revealing that the hydrodynamic and electric force were both dominant and interactional during the transmission process. The consistency of the results from the experimental analysis and simulation modeling proved the validity of the model, which was helpful for understanding ion activity in transfer capillaries. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
947.
948.
Longsheng Zhang Liping Wang Haiping Lin Yunxia Liu Jinyu Ye Yunzhou Wen Ao Chen Lie Wang Fenglou Ni Zhiyou Zhou Shigang Sun Youyong Li Bo Zhang Huisheng Peng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(47):16976-16981
The electrocatalytic urea oxidation reaction (UOR) provides more economic electrons than water oxidation for various renewable energy‐related systems owing to its lower thermodynamic barriers. However, it is limited by sluggish reaction kinetics, especially by CO2 desorption steps, masking its energetic advantage compared with water oxidation. Now, a lattice‐oxygen‐involved UOR mechanism on Ni4+ active sites is reported that has significantly faster reaction kinetics than the conventional UOR mechanisms. Combined DFT, 18O isotope‐labeling mass spectrometry, and in situ IR spectroscopy show that lattice oxygen is directly involved in transforming *CO to CO2 and accelerating the UOR rate. The resultant Ni4+ catalyst on a glassy carbon electrode exhibits a high current density (264 mA cm?2 at 1.6 V versus RHE), outperforming the state‐of‐the‐art catalysts, and the turnover frequency of Ni4+ active sites towards UOR is 5 times higher than that of Ni3+ active sites. 相似文献
949.
950.
The decays η,
→ π+π-
l
+
l
- (with l = e,μ are investigated within a chiral unitary approach which combines the chiral effective Lagrangian with a coupled-channels
Bethe-Salpeter equation. Predictions for the decay widths and spectra are given. 相似文献