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991.
992.
Zilei Guo Jiang Ouyang Dr. Na Yoon Kim Prof. Jinjun Shi Prof. Xiaoyuan Ji 《Chemphyschem》2019,20(19):2417-2433
Two-dimensional (2D) nanomaterials have drawn tremendous attention due to their unique physicochemical properties and promising applications in the fields of electronics, energy storage, and catalysis. Recently, the biomedicine community has gradually started to recognize the great potential of these nanostructured materials for biomedical applications – in particular those related to cancer therapy. In this review, we provide a brief overview of a few representative 2D nanomaterials, discuss their preparation strategies and physicochemical properties, and highlight their applications in cancer nanomedicine. We expect that this review will shed some light on the new opportunities associated with 2D nanomaterials for biomedical research. 相似文献
993.
Peng Chen Zhi‐Chao Chen Yue Li Qin Ouyang Wei Du Ying‐Chun Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(12):4076-4080
Auto‐tandem catalysis (ATC), in which a single catalyst promotes two or more mechanistically different reactions in a cascade pattern, provides a powerful strategy to prepare complex products from simple starting materials. Reported here is an unprecedented auto‐tandem cooperative catalysis (ATCC) for Morita–Baylis–Hillman carbonates from isatins and allylic carbonates using a simple Pd(PPh3)4 precursor. Dissociated phosphine generates phosphorus ylides and the Pd leads to π‐allylpalladium complexes, and they undergo a γ‐regioselective allylic–allylic alkylation reaction. Importantly, a cascade intramolecular Heck‐type coupling proceeds to finally furnish spirooxindoles incorporating a 4‐methylene‐2‐cyclopentene motif. Experimental results indicate that both Pd and phosphine play crucial roles in the catalytic Heck reaction. In addition, the asymmetric versions with either a chiral phosphine or chiral auxiliary are explored, and moderate results are obtained. 相似文献
994.
Jiang Ouyang Chan Feng Xiaoyuan Ji Li Li Hemanth Kiran Gutti Na Yoon Kim Dolev Artzi Angel Xie Na Kong You‐Nian Liu Guillermo J. Tearney Xinbing Sui Wei Tao Omid C. Farokhzad 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(38):13539-13544
As a new family member of the emerging two‐dimensional (2D) monoelemental materials (Xenes), germanene has shown promising advantages over the prototypical 2D Xenes, such as black phosphorus (BP) and graphene. However, efficient manufacture of novel germanene nanostructures is still a challenge. Herein, a simple top‐down approach for the liquid‐exfoliation of ultra‐small germanene quantum dots (GeQDs) is presented. The prepared GeQDs possess an average lateral size of about 4.5 nm and thickness of about 2.2 nm. The functionalized GeQDs were demonstrated to be robust photothermal agents (PTAs) with outstanding photothermal conversion efficacy (higher than those of graphene and BPQDs), superior stability, and excellent biocompatibility. As a proof‐of‐principle, 2D GeQDs‐based PTAs were used in fluorescence/photoacoustic/photothermal‐imaging‐guided hyperpyrexia ablation of tumors. This work could expand the application of 2D germanene to the field of photonic cancer nanomedicine. 相似文献
995.
在连续流动固定床反应中,以丙烯醛二乙缩醛、水和氨为原料,合成了吡啶和3-甲基吡啶。 比较了La-和KF-改性Y型分子筛的活性大小,考察了La负载量和改性方式、KF负载量及KF/Y的焙烧温度的影响。 研究结果表明,与纯Y型分子筛相比,La和KF改性Y型分子筛均能增强催化活性。 采用浸渍法和La负载量为1%(质量分数)时,吡啶和3-甲基吡啶总收率达到最高值;与浸渍法相比,采用离子交换法制备La-Y的活性更好。 采用浸渍法、KF负载量为1%(质量分数)和KF/Y的焙烧温度为700 ℃时,吡啶和3-甲基吡啶总收率达到最大值。 相似文献
996.
Y.M. Wang P.F. Zhang L.X. Guo J.H. Ouyang Y. Zhou D.C. Jia 《Applied Surface Science》2009,255(20):8616-8623
Ceramic coatings of different thickness were fabricated on Ti6Al2Zr1Mo1V alloy by microarc oxidation (MAO), and the effect of the coating on fatigue life was evaluated by 810 Material Test System. The microstructure, phase and chemical composition of the coatings were determined by SEM, XRD and EDS techniques. The coating mainly consists of rutile and a small amount of anatase TiO2. With oxidation time ranging from 10 to 30 min, the coating thickness increases from 13 to 25 μm, while the interface between coating and substrate becomes more zigzag, characterized by increasing overgrowth regions of coating into substrate. Under the same cyclic stress of 750 MPa, the fatigue life decreases from 2.08 × 106 cycles for uncoated specimen to about 3 × 104 cycles for microarc oxidized specimen. Under the cyclic stress, the thicker the coating, the more cracks initiate in the overgrowth regions of coating into substrate near the interface, which are considered as the notch sites of stress concentration to induce the crack initiation, also is the key factor to cause the facture. 相似文献
997.
量子通信是一个量子密钥分发过程,目前采用的通信技术严重制约了量子密钥分发的比特率.将多输入多输出(MIMO)技术应用于量子通信系统,提高量子密钥分发的比特率,促进量子通信向高速大容量发展.然而,量子场本身不可避免地存在量子噪声约束容量的增长,限制了可利用空间资源,即空间自由度.文中采用光子场的量子化和满足Schrdinger方程条件的电磁场波动方程推导出MIMO量子信道的空间自由度上限,为开发稳健的MIMO量子通信空时处理算法和优化设计高性能MIMO量子通信系统提供理论基础和技术支持.
关键词:
多输入多输出
量子密钥分发
Schrdinger方程
光子场的量子化 相似文献
998.
利用密度泛函理论研究了0.25单层(ML),0.5ML,0.75ML和1ML吸附率下H2O在SrTiO3-(001)TiO2表面上的吸附行为.比较了不同吸附率下分子吸附和解离吸附的稳定性,利用微动弹性带(nudged elastic band)方法计算了H2O的解离势垒.结果表明:在低吸附率(0.25ML和0.5ML)时,H2O表现为解离吸附;在0.75ML吸附率下,分子吸附和解离吸附同时存在;而在全吸附(吸附率为1ML)时,分子吸附更稳定.基于对H2O分子与表面之间以及H2O分子之间的电荷转移和相互作用的分析,讨论了吸附率对H2O吸附和解离的影响. 相似文献
999.
1000.