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991.
Konarev DV Khasanov SS Saito G Lyubovskaya RN Yoshida Y Otsuka A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(16):3837-3848
A method for the synthesis of the multicomponent ionic complexes: [Cr(I)(C(6)H(6))(2) (.+)][Co(II)(tpp)(fullerene)(-)].C(6)H(4)Cl(2), comprising bis(benzene)chromium (Cr(C(6)H(6))(2)), cobalt(II) tetraphenylporphyrin (Co(II)(tpp)), fullerenes (C(60), C(60)(CN)(2), and C(70)), and o-dichlorobenzene (C(6)H(4)Cl(2)) has been developed. The monoanionic state of the fullerenes has been proved by optical absorption spectra in the UV/vis/NIR and IR ranges. The crystal structures of the ionic [[Cr(I)(C(6)H(6))(2)](.+)](1.7)[[Co(II)(tpp)(C(60))](2)](1.7-). 3.3 C(6)H(4)Cl(2) and [[Cr(I)(C(6)H(6))(2)] (.+)](2)[Co(II)(tpp)[C(60)(CN)(2)]](-)[C(60)(CN)(2) (.-)]).3 C(6)H(4)Cl(2) are presented. The essentially shortened Co.C(fullerene) bond lengths of 2.28-2.32 A in these complexes indicate the formation of sigma-bonded [Co(II)(tpp)][fullerene](-) anions, which are diamagnetic. All the ionic complexes are semiconductors with room temperature conductivity of 2 x 10(-3)-4 x 10(-6) S cm(-1), and their magnetic susceptibilities show Curie-Weiss behavior. The neutral complexes of Co(II)(tpp) with C(60), C(60)(CN)(2), C(70), and Cr(0)(C(6)H(6))(2), as well as the crystal structures of [Co(II)(tpp)](C(60)).2.5 C(6)H(4)Cl(2), [Co(II)(tpp)](C(70)). 1.3 CHCl(3).0.2 C(6)H(6), and [Cr(0)(C(6)H(6))(2)][Co(II)(tpp)] are discussed. In contrast to the ionic complexes, the neutral ones have essentially longer Co.C(fullerene) bond lengths of 2.69-2.75 A. 相似文献
992.
Six mononuclear complexes [M(L1)2(H2O)4] (M = Co(II), 1a and M = Mn(II), 1b), [Cu(L1)2(H2O)2] (1c), [Cu(L1)2(H2O)(Py)2] (1d), [Cu(L3)(H2O)Cl] · H2O (3a) and [Co(Sal)(H2O)(Py)3] · 2ClO4 · H2O (3b) of phenoxyacetic acid derivatives and Schiff base were determined by single crystal X-ray diffraction. The Co(II) (1a) and Mn(II) (1b) complexes are isomorphous. X-ray crystal structural analyses reveal that these coordination complexes form polymeric structure via formation of different types of hydrogen bonding and π-stacking interactions in solid. Thermal analysis along with the powder X-ray diffraction data of these complexes shows the importance of the coordinated and/or crystal water molecules in stabilizing the MOF structure. Complexes 1a, 1c, 3a show marginal catalytic activity in the oxidation of olefins to epoxides in the presence of i-butyraldehyde and molecular oxygen. 相似文献
993.
At present, a new round of scientific and technological revolution and industrial transformation is accelerating, which has put forward higher requirements for the discipline of new energy science and engineering with typical interdisciplinary characteristics. On the background of emerging engineering education, the "new energy science and engineering" discipline is building at Nankai University to cater for the development of renewable energy and to explore the strategies of talent cultivation. The models for talent training, settings of new curriculum system, and forms of teaching practice are presented. The goal is to promote the extension of applied science towards engineering and to foster the cultivation of talents in the new energy field with broad interdisciplinary science-technology horizon and strong practical ability. 相似文献
994.
Efficient utilization of the pentosan fraction of hemicellulose from lignocellulosic feedstocks offers an opportunity to increase
the yield and to reduce the cost of producing fuel ethanol. During prehydrolysis (acid hydrolysis or autohydrolysis of hemicellulose),
acetic acid is formed as a consequence of the deacetylation of the acetylated moiety of hemicellulose. Recombinant Escherichia
coli B (ATCC 11303), carrying the plasmid pLO1297 with pyruvate decarboxylase and alcohol dehydrogenase II genes from Zymomonas
mobilis (CP4), converts xylose to ethanol with a product yield that approaches theoretical maximum. Although other pentose-utilizing
microorganisms are inhibited by acetic acid, the recombinant E. coli displays a high tolerance for acetic acid. In xylose
fermentations with a synthetic medium (Luria broth), where the pH was controlled at 7, neither yield nor productivity was
affected by the addition of 10.7 g/L acetic acid. Nutrient-supplemented, hardwood (aspen) hemicellulose hydrolysate (40.7
g/L xylose) was completely fermented to ethanol (16.3 g/L) in 98 h. When the acetic acid concentration was reduced from 5.6
to 0.8 g/L, the fermentation time decreased to 58 h. Overliming, with Ca(OH)2 to pH 10, followed by neutralization to pH 7 with sulfuric acid and removal of insolubles, resulted in a twofold increase
in volumetric productivity. The maximum productivity was 0.93 g/L/h. The xylose-to-ethanol conversion efficiency and productivity
in Ca(OH)2-treated hardwood prehydrolysate, fortified with only mineral salts, were 94% and 0.26 g/L/h, respectively. The recombinant
E. coli exhibits a xylose-to-ethanol conversion efficiency that is superior to that of other pentose-utilizing yeasts currently
being investigated for the production of fuel ethanol from lignocellulosic materials. 相似文献
995.
Braga D Maini L Giaffreda SL Grepioni F Chierotti MR Gobetto R 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(13):3261-3269
The organometallic zwitterion [Co(III)(eta(5)-C(5)H(4)COOH)(eta(5)-C(5)H(4)COO)] reacts quantitatively as a solid polycrystalline phase with a number of crystalline alkali salts MX (M = K(+), Rb(+), Cs(+), NH(4) (+); X = Cl(-), Br(-), I(-), PF(6)(-), although not in all cation/anion permutations) to afford supramolecular complexes of the formula [Co(III)(eta(5)-C(5)H(4)COOH)(eta(5)-C(5)H(4)COO)](2).M(+)X(-). In some cases, the mechanochemical complexation requires kneading of the two solids with a catalytic amount of water. The characterization of the solid-state products has been achieved by a combination of X-ray single-crystal and powder-diffraction experiments. The hydrogen-bonding interactions have been investigated by solid-state NMR spectroscopy. The mechanochemical reactions imply a profound solid-state rearrangement accompanied by breaking and forming of O-H...O hydrogen-bonding interactions between the organometallic molecules. All compounds could also be obtained by solution crystallization of the inorganic salts in the presence of the organometallic unit. The solid-state complexation of alkali cations by the organometallic zwitterion has been described as a special kind of solvation process taking place in the solid state. 相似文献
996.
《Arabian Journal of Chemistry》2020,13(12):8935-8964
This review depicts the exposure of chitin and chitosan base multifunctional nanomaterial composites for promising applications in field of biomedical science structure, synthesis as well as potential application from a colossal angle. We elaborated critically each of the chitin and chitosan base nanomaterial with its potential application toward biomedical science. For different biomedical applications it use in form of hydrogels, microsphere, nanoparticles, aerogels, microsphere and in form of scaffold. Due to this it had been blended with different polymer such as starch, cellulose, alginate, lipid, hyaluronic acid, polyvinyl alcohol and caboxymethyl cellulose. In this review article, a comprehensive overview of combination of chitin and chitosan base nanomaterial with natural as well as synthetic polymers and their biomedical applications in biomedical field involving drug delivery system all the technical scientific issues have been addressed; highlighting the recent advancements. 相似文献
997.
PLA大分子单体接枝NVP共聚物的合成与性能 总被引:2,自引:0,他引:2
制备了末端为双键的功能化聚乳酸大分子单体(PLA-HEMA),并以此大分子单体与N-乙烯基吡咯烷酮(NVP)进行自由基溶液共聚,合成了具有亲水性PVP-PHEMA主链和疏水性PLA支链的接枝共聚物。用FT-IR1、H-NMR、GPC、DSC、表面接触角测定研究了共聚物的结构与性能。结果表明:共聚物为非晶聚合物;NVP的摩尔投料量对共聚物的性能有显著影响,随NVP投料量增大,共聚物的分子量有所下降,玻璃化转变温度(Tg)增大;由于亲水性PVP和PHEMA链段的引入,共聚物的亲水性优于相应的线型聚乳酸材料。 相似文献
998.
Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films were fabricated by depositing sol-gel solutions on Pt(111)/Ti/SiO2/Si (100) substrates. Crystallographic orientations of the BLT films were random, but the preferred orientations along (00l) and (117) axes were found. All films showed a single-phase bismuth-layered structure but the orientation in the films could
be engineered by optimizing the growth condition, as well as by introducing dopant atoms such as Ce and Zr in the films, which
in turn influenced the ferroelectric properties of the films significantly. The shape of c-axis-oriented grains was more plate-like, while that of (117)-oriented grains was rod-like. Small % substitution of Ce, Mn,
and Zr atoms at Ti site enhanced the remanent polarization by approximately 20%, while substitution of Si atoms reduced the
remanent polarization in BLT films but improved insulating properties. It was also demonstrated that fatigue endurance could
be controlled by the concentration of dopant atoms, which was thought to be due to the decrease in oxygen vacancy concentration. 相似文献
999.
We investigate a chemostat model in which the growth rate is given by a Monod expression with a variable yield coefficient.
This model has been investigated by previous researchers using numerical integration. We combine analytical results with path-following
methods. The conditions for washout to occur are found. When washout does not occur we establish the conditions under which
the reactor performance is maximised at either a finite or infinite residence time. We also determine the parameter region
in which oscillations may be generated in the reactor, which was the primary feature of interest to earlier workers on this
problem. 相似文献
1000.
R. Jrme Ph. Teyssi B. Vuillemin T. Zundel C. Zune 《Journal of polymer science. Part A, Polymer chemistry》1999,37(1):1-10
The constant progress of the anionic polymerization of (meth)acrylates is discussed from both the fundamental and practical points of view. A special attention is paid to the improved macromolecular engineering of (meth)acrylate‐based (co)polymers. The resulting most important materials and the scaling‐up process needed for their production are also emphasized. The recent developments witness for the healthy state of the anionic polymerization of these polar monomers. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1–10, 1999 相似文献