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21.
Jerzy Bialkowski Karin Erdmann Andrzej Skowronski 《Transactions of the American Mathematical Society》2007,359(6):2625-2650
We introduce the class of deformed preprojective algebras of generalized Dynkin graphs (), (), , , and () and prove that it coincides with the class of all basic connected finite-dimensional self-injective algebras for which the inverse Nakayama shift of every non-projective simple module is isomorphic to its third syzygy .
22.
23.
Light‐induced degradation (LID) has been identified to be a critical issue for solar cells processed on boron‐doped silicon substrates. Typically, Czochralski‐grown silicon (Cz‐Si) has been reported to suffer from stronger LID than block‐cast multicrystalline silicon (mc‐Si) due to higher oxygen concentrations. This work investigates LID under conditions practically relevant under module operation on different cell types. It is shown that aluminium oxide (AlOx) passivated mc‐Si solar cells degrade more than a reference aluminium back surface field mc‐Si cell and, remarkably, an AlOx passivated Cz‐Si solar cell. The defect which is activated by illumination is shown to be doubtful a sole bulk effect while the AlOx passivation might play a certain role. This work may contribute to a re‐evaluation of the suitability of boron‐doped Cz‐ and mc‐Si for solar cells with very high efficiencies. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
24.
Igor Tkach Karin Halbmair Claudia Höbartner Marina Bennati 《Applied magnetic resonance》2014,45(10):969-979
Pulsed electron–electron double resonance (PELDOR/DEER) at high frequencies can provide information on the relative orientation of paramagnetic centres or spin labels, if those are rigidly oriented in a host biomolecule and experiments are performed with sufficient orientation selectivity. We present the first comparative PELDOR study at 263 and 94 GHz on a model RNA system containing rigid nitroxides. We show that at 263 GHz still considerable modulation depth is observed and orientation selectivity is significant, particularly in g x–g y plane of the nitroxides. 相似文献
25.
Elaina P. Boyle Dr. Levan Lomidze Prof. Dr. Karin Musier-Forsyth Prof. Dr. Besik Kankia 《ChemistryOpen》2022,11(2):e202100276
Nucleic acid quadruplexes are proposed to play a role in the regulation of gene expression, are often present in aptamers selected for specific binding functions and have potential applications in medicine and biotechnology. Therefore, understanding their structure and thermodynamic properties and designing highly stable quadruplexes is desirable for a variety of applications. Here, we evaluate DNA→RNA substitutions in the context of a monomolecular, antiparallel quadruplex, the thrombin-binding aptamer (TBA, GGTTGGTGTGGTTGG) in the presence of either K+ or Sr2+. TBA predominantly folds into a chair-type configuration containing two G-tetrads, with G residues in both syn and anti conformation. All chimeras with DNA→RNA substitutions (G→g) at G residues requiring the syn conformation demonstrated strong destabilization. In contrast, G→g substitutions at Gs with anti conformation increased stability without affecting the monomolecular chair-type topology. None of the DNA→RNA substitutions in loop positions affected the quadruplex topology; however, these substitutions varied widely in their stabilizing or destabilizing effects in an unpredictable manner. This analysis allowed us to design a chimeric DNA/RNA TBA construct that demonstrated substantially improved stability relative to the all-DNA construct. These results have implications for a variety of quadruplex-based applications including for the design of dynamic nanomachines. 相似文献
26.
Lidija Fras Zemljič Zdenka Peršin Per Stenius Karin Stana Kleinschek 《Cellulose (London, England)》2008,15(5):681-690
The influence of peroxide bleaching and slack-mercerization on the amount of acidic groups in regenerated fibres (viscose,
modal and lyocell) were studied. Conductometric titration was used to determine the total content of acidic carboxylic groups.
Polyelectrolyte titration was used for surface and total charge determination, and to obtain information about the charge
distribution and accessibilities of charged groups. Changes in fibre crystallinity to pre-treatment processes were characterized
using iodine sorption (Schwertassek method) and correlated to treatments and the amount of carboxylic groups. For all three
types of fibres the amount of accessible carboxyl groups was lowered by an increase in the degree of crystallinity. Bleaching
with hydrogen peroxide causes some oxidative cellulose damage and, therefore, a larger amount of carboxyl groups (presumably
formed at the end of cellulose chains). Slack-mercerization did not significantly change the total amount of acidic groups
in the fibres, but their accessibility to cationic polyelectrolytes, in particular to polymers with high molecular weight
was substantially lowered.
Lidija Fras Zemljič, Zdenka Peršin, and Karin Stana Kleinschek are the members of the European Polysaccharide Network of Excellence
(EPNOE). 相似文献
27.
Nienhaus K Nar H Heilker R Wiedenmann J Nienhaus GU 《Journal of the American Chemical Society》2008,130(38):12578-12579
An important class of red fluorescent proteins (RFPs) feature a 2-iminomethyl-5-(4-hydroxybenzylidene)imidazolinone chromophore. Among these proteins, eqFP611 has the chromophore in a coplanar trans orientation, whereas the cis isomer is preferred by other RFPs such as DsRed and its variants. In the photoactivatable protein asFP595, the chromophore can even be switched from the nonfluorescent trans to the fluorescent cis state by light. By using X-ray crystallography, we have determined the structure of dimeric eqFP611 at high resolution (up to 1.1 A). In the far-red emitting eqFP611 variant d2RFP630, which carries an additional Asn143Ser mutation, the chromophore resides predominantly (approximately 80%) in the cis isomeric state, and in RFP639, which has Asn143Ser and Ser158Cys mutations, the chromophore is found completely in the cis form. The pronounced red shift of excitation and emission maxima of RFP639 can thus unambiguously be assigned to trans-cis isomerization of the chromophore. Among RFPs, eqFP611 is thus unique because its chromophore is highly fluorescent in both the cis and trans isomeric forms. 相似文献
28.
Belcher WJ Hodgson MC Sumida K Torvisco A Ruhlandt-Senge K Ware DC Boyd PD Brothers PJ 《Dalton transactions (Cambridge, England : 2003)》2008,(12):1602-1614
The reactions of boron halides with free base porphyrins under conditions where partial hydrolysis of the boron halides can occur give diboron porphyrin complexes containing BOB moieties in which each boron is bonded to two porphyrin nitrogen atoms. BF(3).OEt(2) with H(2)(por) gives B(2)OF(2)(por) (por = tpp, ttp, tpClpp, oep) which has an asymmetric structure in which one boron lies in the porphyrin plane (B(ip)) while the other lies above it (B(oop)). BCl(3).MeCN with H(2)(por) gives B(2)O(2)(BCl(3))(2)(por) which contains a four-membered B(2)O(2) ring and is stable only in the presence of excess BCl(3). BBr(3) with Li(2)(tpClpp) gives the dicationic complex [B(2)O(tpClpp)](2+) as its [BBr(4)](-) salt, and is the first example of a boron porphyrin containing three-coordinate boron to be structurally characterised. B(2)O(2)(BCl(3))(2)(por) can be chromatographed on basic alumina to give the hydroxyboron complex B(2)O(OH)(2)(por), which is deduced from its NMR spectra and DFT calculations to have a structure analogous to B(2)OF(2)(por). The OH protons are shifted upfield to near delta -4 (B(oop)-OH) and -10 (B(ip)-OH) by the diamagnetic porphyrin ring current. The reaction of either B(2)O(2)(BCl(3))(2)(por) or B(2)O(OH)(2)(por) (por = ttp, tpClpp) with alcohols (ROH, R = Et, 4-C(6)H(4)CH(3)) gives B(2)O(OR)(2)(por), which can in turn be converted to B(2)O(OR)(OH)(por) by repeated chromatography. The reaction of PhBCl(2) with H(2)(por) (por = ttp, tpClpp) gives B(2)O(Ph)(OH)(por) which has been characterised by spectroscopy in concert with DFT calculations. It is a further example of the B(2)OF(2)(por) structural type, in which the phenyl group is coordinated to the out-of-plane boron and the OH group to the in-plane boron, as are its derivatives B(2)O(Ph)(X)(tpClpp) (X = F, OEt). Steric drivers for the facile hydrolysis of haloboron porphyrins relative to their dipyrromethene and expanded porphyrin counterparts are discussed. 相似文献
29.
Differential 2-DE (DIGE) is a widely applied tool for the quantitative analysis of differentially represented proteins. The method involves covalent minimal labeling of proteins prior to their electrophoretic separation using CyDye DIGE Fluor minimal dyes. This methodology creates two different species per protein, the labeled (approx. 1-2%) and unlabeled (approx. 98-99%) ones, which differ in their molecular masses by 434-464 Da, depending on the attached dye. DIGE followed by automated spot picking according to the CyDye coordinates misses in many instances the exact positions where the maximum amounts of the considered proteins are located. This fact leads to a loss in sensitivity of the subsequent MALDI-MS analyses and results in a reduced reliability of protein identification and sequence coverage. In this paper, the migration differences of labeled and unlabeled species are quantified together with the impact of this effect on the certainty of protein identification and sequence coverage investigating proteins up to 90 kDa. 相似文献
30.
Pierozan MK Oestreicher EG Oliveira JV Oliveira D Treichel H Cansian RL 《Applied biochemistry and biotechnology》2011,165(1):75-86
The objective of this study was to provide some features on immobilization and partial characterization of lipases from wheat
seeds. The optimum pH and temperature were found to be 5.5 and 32–37 °C, respectively. The stability of the concentrated enzymatic
extract to high temperatures (25, 35, 45, and 55 °C) showed that the incubation of the extract at 55 °C led to its complete
inactivation. The concentrated enzymatic extract kept 90% of its hydrolytic and esterification activities until 70 and 40 days
of storage at 4 °C, respectively. The extract presented higher hydrolytic specificity to substrates of medium and long chains
and higher esterification affinity to fatty acids of short and medium chains and alcohols with two and three carbon atoms.
After the immobilization process using activated coal and sodium alginate as supports, an enhancement of about threefold in
lipase activity was observed. The development of the present work permitted us to point out some characteristics of lipases
from wheat seeds necessary for the proposition of new future industrial applications for this important biocatalyst. 相似文献