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951.
Constantin TP Silva GL Robertson KL Hamilton TP Fague K Waggoner AS Armitage BA 《Organic letters》2008,10(8):1561-1564
A new fluorogenic cyanine dye was synthesized and found to have low fluorescence quantum yield in fluid solution and in the presence of double-stranded DNA but 80-fold enhanced fluorescence in viscous glycerol solution. An RNA aptamer selected for binding to the new dye exhibits K(d) = 87 nM and 60-fold fluorescence enhancement. The dye-aptamer pair is a fluoromodule that can be incorporated into fluorescent sensors and labels. 相似文献
952.
Antonio Cala Jos R. Salcedo Ascensin Torres Rosa M. Varela Jos M. G. Molinillo Francisco A. Macías 《Molecules (Basel, Switzerland)》2021,26(11)
In the search of new alternatives for weed control, spices appear as an option with great potential. They are rich in bioactive natural products and edible, which might minimize toxicity hazard. Marjoram (Origanum majorana L.) is an aromatic herb that has been widely employed as a seasoning herb in Mediterranean countries. Although marjoram boasts a plethora of therapeutic properties (painkiller, antibiotic, treatment for intestinal disorders, etc.), the potential for its extracts for weed control is still to be more thoroughly explored. In order to determine their phytotoxic potential, marjoram leaves were subjected to different bioguided extraction processes, using water, ethyl acetate, acetone or methanol. The most active extract (acetone) was sequentially fractionated to identify its most active compounds. This fractionation led to the isolation and identification of 25 compounds that were classified as monoterpenes, diterpenes or flavonoids. Among them, a new compound named majoradiol and several compounds are described in marjoram for the first time. The phytotoxicity of the major compounds to etiolated wheat coleoptiles was compared against that of the commercial herbicide (Logran®), with similar or higher activity in some cases. These results confirm the extraordinary potential of the extracts from this edible plant to develop safer and more environmentally friendly herbicides. 相似文献
953.
S. N. Liddick R. Grzywacz C. Mazzocchi R. D. Page K. P. Rykaczewski J. C. Batchelder C. R. Bingham I. G. Darby G. Drafta C. Goodin C. J. Gross J. H. Hamilton A. A. Hecht J. K. Hwang S. Ilyushkin D. T. Joss A. Korgul W. Królas K. Lagergren K. Li M. N. Tantawy J. Thomson J. A. Winger 《The European physical journal. Special topics》2007,150(1):131-134
The α-decay chain 109Xe → 105Te → 101Sn was identified at the Holifield Radioactive Ion Beam Facility. Advances in digital electronics have made possible the identification
of both alpha emitters in the same experiment despite the disparate half-lives of 13 ±2 ms and 620 ±70 ns for 109Xe and 105Te, respectively. Two α-decay transitions were observed from 109Xe with Qα values of 4067 ±10 and 4217 ±8 keV. One transition between the ground states of 105Te and 101Sn was observed with a Qα value of 4889 ±6 keV. Using the measured half-lives, branching ratios, and Qα values the reduced α-decay widths, δ2, were determined. Comparison of the δ2 value for 105Te with 213Po indicates a “superallowed" character in the α emission of 105Te. 相似文献
954.
Substitution of the C-11 aniline of mifepristone can provide compounds with altered pharmacokinetic and pharmacodynamic (PK/PD)
profiles that may find use for new indications. The development of new steroid intermediates and specialized library synthesis
methods were required to enable the efficient preparation of structurally complex C-11 modified mifepristone analogs. 相似文献
955.
Perhach Claire Chamberlain Jarom Rood Nathan Hamilton Ethan Simpson Michael F. 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2303-2309
Journal of Radioanalytical and Nuclear Chemistry - Molten chloride salt fast reactors (MCFRs) will require UCl3 dissolved in molten salt mixtures as fuel for nuclear fission. For infusing the salt... 相似文献
956.
Proteins in nature fold into native conformations in which combinations of peripherally projected aliphatic, aromatic and ionic functionalities direct a wide range of properties. Alpha-helices, one of the most common protein secondary structures, serve as important recognition regions on protein surfaces for numerous protein-protein, protein-DNA and protein-RNA interactions. These interactions are characterized by conserved structural features within the alpha-helical domain. Rational design of structural mimetics of these domains with synthetic small molecules has proven an effective means to modulate such protein functions. In this tutorial review we discuss strategies that utilize synthetic small-molecule antagonists to selectively target essential protein-protein interactions involved in certain diseases. We also evaluate some of the protein-protein interactions that have been or are potential targets for alpha-helix mimetics. 相似文献
957.
Ricardo C. Santana Jesiel F. Carvalho Ivo Vencato Hamilton B. Napolitano Adailton J. Bortoluzzi Gastón E. Barberis Raul E. Rapp Mario C.G. Passeggi Rafael Calvo 《Polyhedron》2007
A novel dinuclear copper(II) complex with the amino acid l-arginine (l-arg), with mono and bidentate HPO42− oxoanions and an OH− anion. [Cu2(l-arg)2(μ-HPO4-O)(μ-HPO4-O,O′)(μ-OH)]− · (H3O)+ · 6H2O (1) was prepared and its structure was determined by X-ray diffraction methods. The two independent copper ions are in a distorted square pyramidal coordination, each bonded to one l-arginine molecule. These two Cu(l-arg) units are bridged by two monoatomic equatorial–apical oxygen ligands belonging to a monodentate hydrogenphosphate group, and to the hydroxyl group. The copper ions in the dinuclear unit at d = 3.1948(8) Å are also connected by two equatorial oxygen belonging to a bidentate hydrogenphosphate. This dinuclear character and bridging scheme, not common for metal–amino acid compounds, is a consequence of the properties of the phosphate anions. The magnetic susceptibility at temperatures between 2 and 300 K and the isothermal magnetization curves at T = 2.29(1) K with applied fields up to 9 T were measured. The magnetic data indicate an antiferromagnetic intradinuclear exchange coupling J/kB = −3.7(1) K and using a molecular field approximation we estimated a weaker ferromagnetic interaction J′/kB ∼ 0.3 K between neighbour dinuclear units. 相似文献
958.
959.
960.
We employ a recently formulated dequantization procedure to obtain an exact expression for the kinetic energy which is applicable to all kinetic-energy functionals. We express the kinetic energy of an N-electron system as the sum of an N-electron classical kinetic energy and an N-electron purely quantum kinetic energy arising from the quantum fluctuations that turn the classical momentum into the quantum momentum. This leads to an interesting analogy with Nelson’s stochastic approach to quantum mechanics, which we use to conceptually clarify the physical nature of part of the kinetic-energy functional in terms of statistical fluctuations and in direct correspondence with Fisher Information Theory. We show that the N-electron purely quantum kinetic energy can be written as the sum of the (one-electron) Weizsäcker term and an (N?1)-electron kinetic correlation term. We further show that the Weizsäcker term results from local fluctuations while the kinetic correlation term results from the nonlocal fluctuations. We then write the N-electron classical kinetic energy as the sum of the (one-electron) classical kinetic energy and another (N?1)-electron kinetic correlation term. For one-electron orbitals (where kinetic correlation is neglected) we obtain an exact (albeit impractical) expression for the noninteracting kinetic energy as the sum of the classical kinetic energy and the Weizsäcker term. The classical kinetic energy is seen to be explicitly dependent on the electron phase, and this has implications for the development of accurate orbital-free kinetic-energy functionals. Also, there is a direct connection between the classical kinetic energy and the angular momentum and, across a row of the periodic table, the classical kinetic energy component of the noninteracting kinetic energy generally increases as Z increases. Finally, we underline that, although our aim in this paper is conceptual rather than practical, our results are potentially useful for the construction of improved kinetic-energy functionals. 相似文献