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81.
In the food industry, food spoilage is a real issue that can lead to a significant amount of waste. Although current preservation techniques are being applied to reduce the occurrence of spoilage microorganisms, the problem persists. Food spoilage yeast are part of this dilemma, with common spoilers such as Zygosaccharomyces, Kluyveromyces, Debaryomyces and Saccharomyces frequently encountered. Antimicrobial peptides derived from plants have risen in popularity due to their ability to reduce spoilage. This study examines the potential application of a synthetic defensin peptide derived from barley endosperm. Its inhibitory effect against common spoilage yeasts, its mechanisms of action (membrane permeabilisation and overproduction of reactive oxygen species), and its stability in different conditions were characterised. The safety of the peptide was evaluated through a haemolysis and cytotoxicity assay, and no adverse effects were found. Both assays were performed to understand the effect of the peptide if it were to be consumed. Its ability to be degraded by a digestive enzyme was also examined for its safety. Finally, the peptide was successfully applied to different beverages and maintained the same inhibitory effects in apple juice as was observed in the antiyeast assays, providing further support for its application in food preservation. 相似文献
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84.
Semicarbazide: occurrence in food products and state-of-the-art in analytical methods used for its determination 总被引:2,自引:0,他引:2
This review provides an overview of the information currently available about the presence of semicarbazide (SEM) in food. Likely sources of SEM in food matrices are summarised and discussed. Detailed information is given about the analytical methods used to determine SEM; features and drawbacks associated with them are carefully evaluated. Performance criteria characterising the analytical methods discussed are also given. 相似文献
85.
A Hundred‐Year‐Old Experiment Re‐evaluated: Accurate Ab Initio Monte Carlo Simulations of the Melting of Radon
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Odile R. Smits Dr. Paul Jerabek Dr. Elke Pahl Prof. Dr. Peter Schwerdtfeger 《Angewandte Chemie (International ed. in English)》2018,57(31):9961-9964
State‐of‐the‐art relativistic coupled‐cluster theory is used to construct many‐body potentials for the noble‐gas element radon to determine its bulk properties including the solid‐to‐liquid phase transition from parallel tempering Monte Carlo simulations through either direct sampling of the bulk or from a finite cluster approach. The calculated melting temperature are 200(3) K and 200(6) K from bulk simulations and from extrapolation of finite cluster values, respectively. This is in excellent agreement with the often debated (but widely cited) and only available value of 202 K, dating back to measurements by Gray and Ramsay in 1909. 相似文献
86.
Horstkotte E Schröder T Niewöhner J Thiel E Jay DG Henning SW 《Photochemistry and photobiology》2005,81(2):358-366
Chromophore-assisted laser inactivation (CALI) is a light-mediated technique used to selectively inactivate proteins of interest to elucidate their biological function. CALI has potential applications to a wide array of biological questions, and its efficiency allows for high-throughput application. A solid understanding of its underlying photochemical mechanism is still missing. In this study, we address the CALI mechanism using a simplified model system consisting of the enzyme beta-galactosidase as target protein and the common dye fluorescein. We demonstrate that protein photoinactivation is independent from dye photobleaching and provide evidence that the first singlet state of the chromophore is the relevant transient state for the initiation of CALI. Furthermore, the inactivation process was shown to be dependent on oxygen and likely to be based on photooxidation of the target protein via singlet oxygen. The simple model system used in this study may be further applied to identify and optimize other CALI chromophores. 相似文献
87.
Duchardt E Richter C Ohlenschläger O Görlach M Wöhnert J Schwalbe H 《Journal of the American Chemical Society》2004,126(7):1962-1970
A new heteronuclear NMR pulse sequence, the quantitative Gamma(HCN) experiment, for the determination of the glycosidic torsion angle chi in (13)C,(15)N-labeled oligonucleotides is described. The Gamma(HCN) experiment allows measurement of CH dipole-dipole, N chemical shift anisotropy cross-correlated relaxation rates (Gamma(C1'H1',N1)(DD,CSA) and Gamma(C2'H2',N9)(DD,CSA) for pyrimidines Gamma(C1'H1'N9)(DD,CSA) and Gamma(C2'H2',N9)(DD,CSA) for purines). A nucleotide-specific parametrization for the dependence of these Gamma-rates on chi based on (15)N chemical shift tensors determined by solid-state NMR experiments on mononucleosides (Stueber, D.; Grant, D. M. J. Am. Chem. Soc. 2002, 124, 10539-10551) is presented. For a 14-mer and a 30-mer RNA of known structures, it is found that the Gamma(HCN) experiment offers a very sensitive parameter for changes in the angle chi and allows restraining of chi with an accuracy of around 10 degrees for residues which do not undergo conformational averaging. Therefore, the Gamma(HCN) experiment can be used for the determination of chi in addition to data derived from (3)J(C,H)-coupling constants. As shown for the 30-mer RNA, the derived torsion angle information can be incorporated as additional restraint, improving RNA structure calculations. 相似文献
88.
Complexes of Rhenium with Planar ReN2S2 Rings. Syntheses and Crystal Structures of AsPh4[ReCl4(N2S2)] and PPh4[ReBr4(N2S2)] The complex [ReCl4(N2S2)]? can be obtained as PPh4⊕ or AsPh4⊕ salt by the action of S(NSiMe3)2 and of diphenylacetylene, respectively, on the chlorothionitrene complex [ReCl4(NSCl)2]?. Another method of synthesis is the reaction of [ReCl3(NSCl)2(POCl3)] with SbPh3. [ReBr3(N2S2)]2 is obtained from excess Me3SiBr and [ReCl3(NSCl)2(POCl3)]. The anionic complex [ReBr4(N2S2)]? forms from either [ReCl4(NSCl)2]? or [ReCl4(N2S2)]? with Me3SiBr. All compounds are black, diamagnetic, and sensitive to moisture; the PPh4⊕ and AsPh4⊕ salts are soluble in CH2Cl2 and CH2Br2. The IR spectra are reported. The crystal structures of AsPh,4[ReCl4(N2S2)] and PPh4[ReBr4(N2S2)] were determined by X-ray diffraction. AsPh4[ReCl4(N2S2)]: space group P2/n, Z = 2, a = 1244.5, b = 1429.3, c = 791.1 pm, γ = 96.89° (1715 observed reflexions, R = 0.082). PPh4[ReBr4[ReBr4(N2S2)]: space group P21/n, Z = 4, a = 961.7, b = 1397.4, c = 2205.7 pm, β = 102.10° (1787 observed reflexions, R = 0.073). In both compounds the [ReX4(N2S2)]? anions have the same type of structure, the Re atoms forming part of planar ReN2S2 rings; the bond lengths are ReN 177 pm, NS 152 pm, and SS 259 for the chloro compound and ReN 184 pm, NS 153 pm, and SS 264 pm for the bromo compound. In AsPh4[ReCl4(N2S2)] the cations are stacked to form columns in the c-direction; in PPh4[ReBr4(N2S2)], there is considerable distortion form this packing principle. 相似文献
89.
Pilot study of capillary electrophoresis coupled to mass spectrometry as a tool to define potential prostate cancer biomarkers in urine 总被引:3,自引:0,他引:3
Theodorescu D Fliser D Wittke S Mischak H Krebs R Walden M Ross M Eltze E Bettendorf O Wulfing C Semjonow A 《Electrophoresis》2005,26(14):2797-2808
We describe the use of capillary electrophoresis (CE) coupled with mass spectrometry (MS) to identify single polypeptides and patterns of polypeptides specific for prostate cancer (CaP) in human urine. Using improved sample preparation methods that enable enhanced comparability between different samples, we examined samples from 47 patients who underwent prostate biopsy. Of this group, 21 patients had benign pathology and 26 with CaP, and these were used to define potential biomarkers, which allow discrimination between these two states. In addition, CE-MS data from these 47 urine samples were compared to that of 41 young men (control) without known or suspected clinical CaP to further confirm the polypeptides indicative for CaP. Upon crossvalidation of the same samples, several polypeptides were selected that enabled correct classification of the CaP patients with 92% sensitivity and 96% specificity. We then examined an additional 474 samples from patients with renal disease enrolled in other studies and found that 14 (3%) had polypeptides suggestive of CaP possibly indicating that they harbor clinical CaP. In conclusion, this early pilot study suggests that CE-MS of urine warrants further investigation as a tool that can identify putative biomarkers for CaP. 相似文献
90.
The reaction of thioureas with 3-bromomethyl-2-cyanocinnamonitrile gives the hydrobromides either of the 2-aminothiazoles or of the hitherto unknown 2-imino-3-thiazolines. 相似文献