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21.
The main techniques developed to characterize chitosan are recalled. The interaction of chitosan with oppositely charged surfactants was investigated giving very important surface activity effects. A few chemical modifications are described and the new properties obtained are mentioned: alkylation gives amphiphilic polymers having interesting thickening behavior; grafting cyclodextrin (chit‐CD) gives a polymer able to include hydrophobic molecules; grafting adamantane gives an amphiphilic polymer able to specifically interact with chit‐CD forming a temporary network with gel‐like behavior.

The viscosities of adamantane‐chitosan, cyclodextrin‐chitosan, and unmodified chitosan solutions studied here.  相似文献   

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An effective anti-cancer therapy should exclusively target cancer cells and trigger in them a broad spectrum of cell death pathways that will prevent avoidance. Here, we present a new approach in cancer therapy that specifically targets the mitochondria and ER of cancer cells. We developed a peptide derived from the flexible and transmembrane domains of the human protein NAF-1/CISD2. This peptide (NAF-144-67) specifically permeates through the plasma membranes of human epithelial breast cancer cells, abolishes their mitochondria and ER, and triggers cell death with characteristics of apoptosis, ferroptosis and necroptosis. In vivo analysis revealed that the peptide significantly decreases tumor growth in mice carrying xenograft human tumors. Computational simulations of cancer vs. normal cell membranes reveal that the specificity of the peptide to cancer cells is due to its selective recognition of their membrane composition. NAF-144-67 represents a promising anti-cancer lead compound that acts via a unique mechanism.

An effective anti-cancer therapy should exclusively target cancer cells and trigger in them a broad spectrum of cell death pathways that will prevent avoidance.  相似文献   
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This paper describes the application of a novel broadband acoustic sensor to evaluating the acoustic emissions from cavitation produced by a typical commercial 20 kHz sonochemical horn processor. Investigations of the reproducibility of the processor, and of the variation in cavitation emissions as a function of output setting and sensor location are described, and resulting trends discussed in terms of the broadband integrated power in the megahertz frequency range. Companion studies with a conventional membrane hydrophone have illustrated for the first time that cavitation emissions produced by a sonochemical horn processor can extend to frequencies beyond 20 MHz, and the sensor shows that significant nonlinearity can be seen in measured cavitation activity with increasing nominal output power.  相似文献   
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A series of N‐(ferrocenylmethyl amino acid) fluorinated benzene‐carboxamide derivatives 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i and 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i have been synthesized by coupling ferrocenylmethyl amine 3 with various substituted N‐(fluorobenzoyl) amino acid derivatives using the standard N‐(3‐dimethylaminopropyl)‐N′‐ethylcarbodiimide hydrochloride, 1‐hydroxybenzotriazole protocol. The amino acids employed in this study were glycine and L‐alanine. All of the compounds were fully characterized using a combination of 1H NMR, 13C NMR, 19F NMR, distortionless enhancement by polarization transfer (DEPT)‐135, 1H–1H correlation spectroscopy (COSY) and 1H–13C COSY (heteronuclear multiple‐quantum correlation) spectroscopy. The compounds were biologically evaluated on the oestrogen‐positive MCF‐7 breast cancer cell line. Compounds 4g , 4i , 5h and 5i exhibited cytotoxic effects on the MCF‐7 breast cancer cell line. N‐(Ferrocenylmethyl‐L‐alanine)‐3,4,5‐trifluorobenzene‐carboxamide ( 5h ) was the most active compound, with an IC50 value of 2.84 μm . Compounds 4i , 5h and 5i had lower IC50 values than that found for the clinically employed anticancer drug cisplatin (IC50 = 16.3 μm against MCF‐7). Guanine oxidation studies confirmed that 5h was capable of generating oxidative damage via a reactive oxygen species‐mediated mechanism. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
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We propose an agent-based model to simulate the creation of street gang rivalries. The movement dynamics of agents are coupled to an evolving network of gang rivalries, which is determined by previous interactions among agents in the system. Basic gang data, geographic information, and behavioral dynamics suggested by the criminology literature are integrated into the model. The major highways, rivers, and the locations of gangs’ centers of activity influence the agents’ motion. We use a policing division of the Los Angeles Police Department as a case study to test our model. We apply common metrics from graph theory to analyze our model, comparing networks produced by our simulations and an instance of a Geographical Threshold Graph to the existing network from the criminology literature.  相似文献   
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Highlights? Growth arrest induced by human telomerase in yeast is chemically reversible ? Readout is sensitive to telomerase catalytic activity and telomere recruitment ? Three cell-permeable compounds also inhibit purified human telomerase ? Yeast can be successfully used to screen for human telomerase inhibitors  相似文献   
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We present a new software to easily perform QM:MM and QM:QM' calculations called QMX. It follows the subtraction scheme and it is implemented in the Atomic Simulation Environment (ASE). Special attention is paid to couple molecular calculations with periodic boundaries approaches. QMX inherits the flexibility and versatility of the ASE package: any combination of methods namely force field, semiempirical, first principle, and ab initio, can be used as hybrid potential energy surface (PES). Its ease of use is demonstrated by considering the adsorption of Al2Cl3Me3 on silica surface and by combining different levels of theory (from standard DFT to MP2 calculations) for the so‐called High Level cluster with standard PW91 density functional theory calculations for the Low Level environment. It is shown that the High Level cluster must contain the silanol group close to the aluminum atoms. The bridging adsorption is favored by 58 kJ mol?1 at the MP2:PW91 level with respect to the terminal position. Using large clusters at the MP2:PW91 level, it is shown that PW91 calculations are sufficient for structure optimization but that embedded methods are required for accurate energy profiles. © 2013 Wiley Periodicals, Inc.  相似文献   
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