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51.
52.
Ya‐Chu Hsieh Hau‐Yu Fang Yi‐Ting Chen Rong Yang Chen‐I Yang Pi‐Tai Chou Ming‐Yu Kuo Yao‐Ting Wu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(10):3112-3116
The syntheses, structures, and physical properties of dibenzozethrenes were explored. The results thus obtained were compared with those for zethrenes. Dibenzozethrenes were synthesized by the nickel‐catalyzed cyclodimerization of 9‐ethynyl‐1‐iodoanthracenes. The substituents in zethrene and dibenzozethrene twisted their backbones, and remarkably influenced their properties. Unlike closed‐shell disubstituted derivatives, the parent zethrene and dibenzozethrene are singlet open‐shell biradicals, which were studied by variable‐temperature 1H NMR, ESR, SQUID and computational methods. Since substituents were observed to affect significantly the biradical properties, the relevant mechanisms were analyzed. The nonlinear optical performance of each of these compounds depends on its π‐conjugation and biradical properties. Dibenzozethrenes have larger two‐photon absorption cross‐sections than zethrenes, as most strongly evidenced by the parent dibenzothrene [σmax=4323 GM at 530 nm]. 相似文献
53.
Yi-Chun Lin Yuan-Yung Lin Hsin-Chien Chen Chao-Yin Kuo Ai-Ho Liao Ying-Liang Chou Chia-Lien Hung Cheng-Ping Shih Chih-Hung Wang 《Molecules (Basel, Switzerland)》2021,26(12)
The application of insulin-like growth factor 1 (IGF-1) to the round window membrane (RWM) is an emerging treatment for inner ear diseases. RWM permeability is the key factor for efficient IGF-1 delivery. Ultrasound microbubbles (USMBs) can increase drug permeation through the RWM. In the present study, the enhancing effect of USMBs on the efficacy of IGF-1 application and the treatment effect of USMB-mediated IGF-1 delivery for noise-induced hearing loss (NIHL) were investigated. Forty-seven guinea pigs were assigned to three groups: the USM group, which received local application of recombinant human IGF-1 (rhIGF-1, 10 µg/µL) following application of USMBs to the RWM; the RWS group, which received IGF-1 application alone; and the saline-treated group. The perilymphatic concentration of rhIGF-1 in the USM group was 1.95- and 1.67- fold of that in the RWS group, 2 and 24 h after treatment, respectively. After 5 h of 118 dB SPL noise exposure, the USM group had the lowest threshold shift in auditory brainstem response, least loss of cochlear outer hair cells, and least reduction in the number of synaptic ribbons on postexposure day 28 among the three groups. The combination of USMB and IGF-1 led to a better therapeutic response to NIHL. Two hours after treatment, the USM group had significantly higher levels of Akt1 and Mapk3 gene expression than the other two groups. The most intense immunostaining for phosphor-AKT and phospho-ERK1/2 was detected in the cochlea in the USM group. These results suggested that USMB can be applied to enhance the efficacy of IGF-1 therapy in the treatment of inner ear diseases. 相似文献
54.
Shin-Hun Juang Min-Tsang Hsieh Pei-Ling Hsu Ju-Ling Chen Hui-Kang Liu Fong-Pin Liang Sheng-Chu Kuo Chen-Yuan Chiu Shing-Hwa Liu Chen-Hsi Chou Tian-Shung Wu Hsin-Yi Hung 《Molecules (Basel, Switzerland)》2021,26(1)
Constitutive androstane receptor (CAR) activation has found to ameliorate diabetes in animal models. However, no CAR agonists are available clinically. Therefore, a safe and effective CAR activator would be an alternative option. In this study, sixty courmarin derivatives either synthesized or purified from Artemisia capillaris were screened for CAR activation activity. Chemical modifications were on position 5,6,7,8 with mono-, di-, tri-, or tetra-substitutions. Among all the compounds subjected for in vitro CAR activation screening, 6,7-diprenoxycoumarin was the most effective and was selected for further preclinical studies. Chemical modification on the 6 position and unsaturated chains were generally beneficial. Electron-withdrawn groups as well as long unsaturated chains were hazardous to the activity. Mechanism of action studies showed that CAR activation of 6,7-diprenoxycoumarin might be through the inhibition of EGFR signaling and upregulating PP2Ac methylation. To sum up, modification mimicking natural occurring coumarins shed light on CAR studies and the established screening system provides a rapid method for the discovery and development of CAR activators. In addition, one CAR activator, scoparone, did showed anti-diabetes effect in db/db mice without elevation of insulin levels. 相似文献
55.
Dr. Andrey Belyaev Prof. Pi-Tai Chou Prof. Igor O. Koshevoy 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(2):537-552
Tunable electron-accepting properties of the cationic phosphorus center, its geometry and unique preparative chemistry that allows combining this unit with diversity of π-conjugated motifs, define the appealing photophysical and electrochemical characteristics of organophosphorus ionic chromophores. This Minireview summarizes the achievements in the synthesis of the π-extended molecules functionalized with P-cationic fragments, modulation of their properties by means of structural modification, and emphasizes the important effect of cation-anion interactions, which can drastically change physical behavior of these two-component systems. 相似文献
56.
Dr. Cheng‐Chung Lee Dr. Manuel Maestre‐Reyna Dr. Kai‐Cheng Hsu Prof. Dr. Hao‐Ching Wang Prof. Dr. Chia‐I Liu Prof. Dr. Wen‐Yih Jeng Li‐Ling Lin Richard Wood Dr. Chia‐Cheng Chou Prof. Dr. Jinn‐Moon Yang Prof. Dr. Andrew H.‐J. Wang 《Angewandte Chemie (International ed. in English)》2014,53(48):13054-13058
Crown ethers are small, cyclic polyethers that have found wide‐spread use in phase‐transfer catalysis and, to a certain degree, in protein chemistry. Crown ethers readily bind metallic and organic cations, including positively charged amino acid side chains. We elucidated the crystal structures of several protein‐crown ether co‐crystals grown in the presence of 18‐crown‐6. We then employed biophysical methods and molecular dynamics simulations to compare these complexes with the corresponding apoproteins and with similar complexes with ring‐shaped low‐molecular‐weight polyethylene glycols. Our studies show that crown ethers can modify protein surface behavior dramatically by stabilizing either intra‐ or intermolecular interactions. Consequently, we propose that crown ethers can be used to modulate a wide variety of protein surface behaviors, such as oligomerization, domain–domain interactions, stabilization in organic solvents, and crystallization. 相似文献
57.
First-principle pseudopotential plane wave calculations and the Nudged Elastic Band method based on density functional theory (DFT) have been used in this article to study the dissociation of molecular hydrogen on a Mg(0001) surface and the subsequent diffusion of atomic hydrogen into the magnesium substrate. First, the dissociation pathway of H2 and the relative barrier were investigated. It was shown that physical adsorption rather than chemisorption of molecular hydrogen was observed in the calculation of the dissociation process of molecular hydrogen. Also, the diffusion process of atomic hydrogen on Mg(0001) was presented. The surface effect, which affected the diffusion of hydrogen obviously, was observed. Finally, comparing the values of the activation energies for the steps of dissociation, diffusion, and desorption, our calculation further showed that the dissociation of H2 and the desorption of hydride were the rate-limiting steps. 相似文献
58.
There is controversy regarding the surface enhancement of Raman scattering due to liquid Hg, and the enhancement of benzoic acid molecules adsorbed on liquid Hg has been determined to be essentially zero. However, if the noise error bar is taken into account, the maximum enhancement is estimated to be less than 30. The same enhancement was observed when the temperature was reduced in solidifying liquid Hg. 相似文献
59.
TIAN CHOU 《高校应用数学学报(英文版)》1994,9(4):319-324
SYMMETRIESANDGROUP-INVARIANTSOLUTIONSOFDIFFERENTIALEQUATIONSTIANCHOUAbstract:Foradifferentialequation,atheoreticalproofofther... 相似文献
60.
de Riedmatten H Laurat J Chou CW Schomburg EW Felinto D Kimble HJ 《Physical review letters》2006,97(11):113603
Violations of a Bell inequality are reported for an experiment where one of two entangled qubits is stored in a collective atomic memory for a user-defined time delay. The atomic qubit is found to preserve the violation of a Bell inequality for storage times up to 21 micros, 700 times longer than the duration of the excitation pulse that creates the entanglement. To address the question of the security of entanglement-based cryptography implemented with this system, an investigation of the Bell violation as a function of the cross correlation between the generated nonclassical fields is reported, with saturation of the violation close to the maximum value allowed by quantum mechanics. 相似文献