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991.
Instudyonnewpharmaceuticalsandagrochemicals,theapplicationofheterocyclesisaveryimportantmethod,whichcanimprovethebiologicalactivities.Intheseyears.moreandmorenewagrochemicalshavebeensynthesizedwhichhavethestructurescontainingheterocycles.especiallypy... 相似文献
992.
Xu Jie Zhao Shanghong Hou Rui Li Xiaoliang Wu Jili Li Yunxia Meng Wen Ni Yanhui Ma Lihua 《Optics and Lasers in Engineering》2009,47(7-8):800-806
To complete a successful laser jamming to imaging charge coupled device (CCD) based on combined fiber lasers, the interactions between CCD and combined fiber lasers were analyzed in detail. The saturation and crosstalk thresholds of CCD were achieved, which are lower than 10 mW/cm2. Through theoretical analysis and numerical simulations, the thermal processes under single pulse, multi-pulses and continuous laser irradiations were developed. The simulation results have proved the possibility of hard damage caused by multi-pulses and continuous laser irradiations. The combined fiber lasers is suitable to deploy optical saturation jamming at present. The further applications of combined fiber lasers need a more powerful laser source and a more accurate tracking and pointing system. 相似文献
993.
Herman Lock Jincheng Xiong Yuan-Chung Wen Bruce A. Parkinson Gary E. Maciel 《Solid state nuclear magnetic resonance》2001,20(3-4)
Solid-state 29Si, 113Cd, 119Sn, and 31P MAS NMR spectra are reported on a series of II-IV-P2 compounds. In favorable cases (e.g., high degree of crystallinity, low concentration of unpaired electrons), well-defined spectra, with sharp lines for each specific nearest-neighbor configuration, are observed; in such cases, expected J coupling patterns are also seen. High-resolution solid-state NMR studies of this type provide useful information on structure (disorder), doping, and electron-mediated coupling in semiconductor systems. 相似文献
994.
1-Amino-5-naphtholisanimportantintermediateproductfororganicsynthesis'.Itwastraditionallysynthesizedfroma-nityonaphthalenebychemicalmethod.HO:wever,thechemicalmethodneedstwostepsandproducesalargequantityofwastewater,indicatingthehigherenergyconsumptionandpollution.Inthispaper,theelectrochemicalreductionofa-nitronaphthalenetol-amino-5-naphtholwasfirstputforward,theelectrochemicalreductioncharacteristicsofa-nitronaphthalenetol-amino-5-naphtholwerestudiedandthereactionmechanismwasproposedaswell.… 相似文献
995.
2-Aminoethylphosphonic acid (AEPA) and its N-substituted compounds were prepared by one step reaction using 2-chloroethylphosphonic acid with ammonia and amines (H2NMe, HNMeMe, HNEtEt, H2NPr-n, H2NCH2ph, H2NCH2CH2NH2 and H2N(C=NH)NH2 in a dilute alkaline solution below 20 °C with simple work-up and easy purification. The reaction was accelerated by catalytic amount of potassium iodide. The yield for the reaction products were 35.6 to 48.6% for the KI absence and 78.2 to 88.0% for the KI presence. 相似文献
996.
997.
Xiao-Rong Wu Chen-Wei Wu Fei Ding Cheng Tian Wen Jiang Cheng-De Mao Chuan Zhang 《中国化学快报》2017,28(4):851-856
Discrete and symmetric three-dimensional(3D)DNA nanocages have been revoked as excellent candidates for various applications,such as guest component encapsulation and organization(e.g.dye molecules,proteins,inorganic nanoparticles,etc.)to construct new materials and devices.To date,a large variety of DNA nanocages has been synthesized through assembling small individual DNA motifs into predesigned structures in a bottom-up fashion.Most of them rely on the assembly using multiple copies of single type of motifs and a few sophisticated nanostructures have been engineered by co-assembling multi-types of DNA tiles simultaneously.However,the availability of complex DNA nanocages is still limited.Herein,we demonstrate that highly symmetric DNA nanocages consisted of binary DNA point-star motifs can be easily assembled by deliberately engineering the sticky-end interaction between the component building blocks.As such,DNA nanocages with new geometries,including elongated tetrahedron(E-TET),rhombic dodecahedron(R-DOD),and rhombic triacontahedron(R-TRI)are successfully synthesized.Moreover,their design principle,assembly process,and structural features are revealed by polyacryalmide gel electrophoresis(PAGE),atomic force microscope(AFM)imaging,and cryogenic transmission electron microscope imaging(cryo-TEM)associated with single particle reconstruction. 相似文献
998.
Ying‐Hui Wang Li‐Jing Gong Wen‐Yue Dong Ping Lu Zhi‐Hui Kang Tian‐Hao Huang Yu‐Guang Ma Han‐Zhuang Zhang 《Journal of Polymer Science.Polymer Physics》2013,51(12):992-997
The photoexcitation processes of two donor–acceptor‐type copolymers PCFBT with different ratios between the donor and the acceptor ( PCFBT0.5 and PCFBT0.1 ) in the solution system are systematically studied. If the number of the donor is equal to that of the acceptor in one repeat unit (such as PCFBT0.5 ), intrachain charge transfer (ICT) can occur and participate in the relaxation of the excited state after photoexcitation. When the number of donors is much larger than that of acceptors (such as PCFBT0.1 ) in one repeat unit, the ICT character can disappear, and the localized exciton decay process is dominant in the relaxation of the copolymer, which also involves an excitation intensity‐independent vibrational thermal relaxation process at the initial time. The results further the understanding of the basic structure‐property relationship. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013 , 51, 992–996 相似文献
999.
Du‐Qiang Luo Wen‐Liang Zhu Xiao‐Long Yang Shu‐Juan Liang Zhi‐Ran Cao 《Helvetica chimica acta》2010,93(6):1209-1215
Two new daphniphyllum alkaloids named 2‐hydroxyyunnandaphnine D ( 1 ) and methyl 7‐hydroxyhomodaphniphyllate ( 2 ), together with eight known alkaloids, daphnioldhanin D, calyciphylline F, calyciphylline B, deoxycalyciphylline B, daphnicyclidin H, macropodumine C, 9,10‐epoxycalycine A, and yunnandaphnine A, were isolated from the stems and leaves of Daphniphyllum calycinum. Their structures and relative configurations were established on the basis of spectral evidence (including 2D‐NMR) and subsequently confirmed by a single‐crystal X‐ray crystallographic diffraction analysis. 相似文献
1000.
Hydroformylation of oct‐1‐ene leading to nonanal (denoted by n) and 2‐methyloctanal (denoted by iso), in a novel series of caprolactam‐based and common imidazolium‐based ionic liquid crystals (ILCs; see Fig. 1) carried out for the first time (caprolactam=hexahydro‐2H‐azepin‐2‐one) (Scheme). Variation of the chain length (n) of the alkyl substituent (Cn) at the caprolactam cation (CP+) from n=12 to 18 caused the n/iso ratios to vary from 1.7 to 2.9. Meanwhile, the TOF (turnover frequency) decreased from 148 to 122 mol mol−1 h−1. Hydroformylation in the imidazolium‐based ILCs revealed that [C16MIm]⋅BF4 (n/iso 5.2, TOF 969 mol mol−1 h−1) was more favorable than [C16MIm]⋅MsO (n/iso 3.7, TOF 969 mol mol−1 h−1) for the formation of the unbranched aldehyde. Although the n/iso ratio in caprolactam‐based ILCs was lower than that in imidazolium‐based ILCs, the conversions are higher in the former ILCs on the whole. It should be noted that the lamellar mesophase has a strong effect on the regioselectivity and TOF of the hydroformylation. Also, it is evident that the influences of different ILCs on the hydroformylation under the various reaction conditions are greatly different. The identification of the reaction products was established by GC and GC/MS analyses. 相似文献