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81.
Antibacterial membranes based on chitosan and quaternary ammonium salts modified nanocrystalline cellulose 下载免费PDF全文
Ying Liu Mei Li Mingyu Qiao Xuehong Ren Tung‐Shi Huang Gisela Buschle‐Diller 《先进技术聚合物》2017,28(12):1629-1635
Etherification of nanocrystalline cellulose (NCC) with three kinds of quaternary ammonium salts epoxypropyltrimethylammonium chloride, N,N‐dimethyl‐N‐dodecyl‐N‐(1,2‐epoxypropyl) ammonium chloride (DMDEPAC), and N,N‐dimethyl‐N‐octadecyl‐N‐(1,2‐epoxypropyl) ammonium chloride (DMOEPAC) was successfully performed via a nucleophilic addition reaction. The synthesized DMDEPAC and DMOEPAC were characterized by nuclear magnetic resonance. The modified NCC particles, NCC epoxypropyltrimethylammonium chloride, NCC‐DMDEPAC, and NCC‐DMOEPAC, were characterized by energy dispersive spectrometer. Nanocomposite films based on chitosan (CS) containing quaternary ammonium salts modified NCC were prepared with nanoparticle loadings of 5.0, 7.5, and 10.0%, respectively. The effect of nanoparticle content on the tensile strength of composite films was studied. The results indicated that the films with 5.0% nanoparticle loading exhibited the biggest increase in tensile strength. Surface morphology, smoothness, and antibacterial properties of composite films containing 5% modified NCC were also studied. CS/NCC‐DMDEPAC‐5.0 and CS/NCC‐DMOEPAC‐5.0 displayed excellent biocidal abilities against both Gram‐positive Staphylococcus aureus (ATCC 6538) and Gram‐negative Escherichia coli O157:H7 (ATCC 43895). The bio‐based nanocomposite films with increased mechanical strength and excellent antibacterial properties show great potential as food packaging materials. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
82.
Cheng Y Cui W Chen Q Tung CH Ji M Zhang F 《Journal of computer-aided molecular design》2011,25(2):171-180
Aurora kinase family is one of the emerging targets in oncology drug discovery and several small molecules targeting aurora
kinases have been discovered and evaluated under early phase I/II trials. Among them, PHA-739358 (compound 1r) is a 3-aminopyrazole
derivative with strong activity against Aurora A under early phase II trial. Inhibitory potency of compound 1r (the benzylic
substituent at the pro-R position) is 30 times over that of compound 1s (the benzylic substituent at the pro-S position).
In present study, the mechanism of how different configurations influence the binding affinity was investigated using molecular
dynamics (MD) simulations, free energy calculations and free energy decomposition analysis. The predicted binding free energies
of these two complexes are consistent with the experimental data. The analysis of the individual energy terms indicates that
although the van der Waals contribution is important for distinguishing the binding affinities of these two inhibitors, the
electrostatic contribution plays a more crucial role in that. Moreover, it is observed that different configurations of the
benzylic substituent could form different binding patterns with protein, thus leading to variant inhibitory potency of compounds
1r and 1s. The combination of different molecular modeling techniques is an efficient way to interpret the chirality effects
of inhibitors and our work gives valuable information for the chiral drug design in the near future. 相似文献
83.
84.
Tung VC Huang JH Tevis I Kim F Kim J Chu CW Stupp SI Huang J 《Journal of the American Chemical Society》2011,133(13):4940-4947
Heterojunctions between different graphitic nanostructures, including fullerenes, carbon nanotubes and graphene-based sheets, have attracted significant interest for light to electrical energy conversion. Because of their poor solubility, fabrication of such all-carbon nanocomposites typically involves covalently linking the individual constituents or the extensive surface functionalization to improve their solvent processability for mixing. However, such strategies often deteriorate or contaminate the functional carbon surfaces. Here we report that fullerenes, pristine single walled carbon nanotubes, and graphene oxide sheets can be conveniently coassembled in water to yield a stable colloidal dispersion for thin film processing. After thermal reduction of graphene oxide, a solvent-resistant photoconductive hybrid of fullerene-nanotube-graphene was obtained with on-off ratio of nearly 6 orders of magnitude. Photovoltaic devices made with the all-carbon hybrid as the active layer and an additional fullerene block layer showed unprecedented photovoltaic responses among all known all-carbon-based materials with an open circuit voltage of 0.59 V and a power conversion efficiency of 0.21%. The ease of making such surfactant-free, water-processed, carbon thin films could lead to their wide applications in organic optoelectronic devices. 相似文献
85.
Culture of cells as three-dimensional (3D) aggregates can enhance in vitro tests for basic biological research as well as for therapeutics development. Such 3D culture models, however, are often more complicated, cumbersome, and expensive than two-dimensional (2D) cultures. This paper describes a 384-well format hanging drop culture plate that makes spheroid formation, culture, and subsequent drug testing on the obtained 3D cellular constructs as straightforward to perform and adapt to existing high-throughput screening (HTS) instruments as conventional 2D cultures. Using this platform, we show that drugs with different modes of action produce distinct responses in the physiological 3D cell spheroids compared to conventional 2D cell monolayers. Specifically, the anticancer drug 5-fluorouracil (5-FU) has higher anti-proliferative effects on 2D cultures whereas the hypoxia activated drug commonly referred to as tirapazamine (TPZ) are more effective against 3D cultures. The multiplexed 3D hanging drop culture and testing plate provides an efficient way to obtain biological insights that are often lost in 2D platforms. 相似文献
86.
Nguyen HT Tran HQ Nguyen TT Chau VM Bui KA Pham QL Nguyen MC Kim YH 《Chemical & pharmaceutical bulletin》2011,59(11):1417-1420
Ten oleanane-type saponins (1-10), including three new compounds, namely bifinosides A-C (1-3), were isolated from the roots of Panax bipinnatifidus SEEM. Their structures were elucidated on the basis of chemical and spectroscopic methods. 相似文献
87.
Tung HT Hwu Y Chen IG Tsai MG Song JM Kempson IM Margaritondo G 《Chemical communications (Cambridge, England)》2011,47(32):9152-9154
CuGaS(2) nanorods were synthesized by irradiating the precursor solution with intense X-rays. The products are single crystal nanorods with preferential [220] growth and a uniform size distribution. We also report on the photoresponse of drop-cast films of these nanorods. 相似文献
88.
Ding T Tian Y Liang K Clays K Song K Yang G Tung CH 《Chemical communications (Cambridge, England)》2011,47(8):2429-2431
Oxygen plasma etching of electrospun polymer fibers containing spherical colloids is presented as a new approach towards anisotropic colloidal nanoparticles. The detailed morphology of the resulting nanoparticles can be precisely controlled in a continuous way. The same approach is also amenable to prepare inorganic nanoparticles with double-sided patches. 相似文献
89.
Douville NJ Zamankhan P Tung YC Li R Vaughan BL Tai CF White J Christensen PJ Grotberg JB Takayama S 《Lab on a chip》2011,11(4):609-619
Studies using this micro-system demonstrated significant morphological differences between alveolar epithelial cells (transformed human alveolar epithelial cell line, A549 and primary murine alveolar epithelial cells, AECs) exposed to combination of solid mechanical and surface-tension stresses (cyclic propagation of air-liquid interface and wall stretch) compared to cell populations exposed solely to cyclic stretch. We have also measured significant differences in both cell death and cell detachment rates in cell monolayers experiencing combination of stresses. This research describes new tools for studying the combined effects of fluid mechanical and solid mechanical stress on alveolar cells. It also highlights the role that surface tension forces may play in the development of clinical pathology, especially under conditions of surfactant dysfunction. The results support the need for further research and improved understanding on techniques to reduce and eliminate fluid stresses in clinical settings. 相似文献
90.