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991.
Sung Bae Kim Hyun Joo Kim Chang Joon Kim 《Applied biochemistry and biotechnology》2006,130(1-3):486-495
Methods of increasing the enzymatic digestibility of waste newspaper by adding Tween (TW)-20 and 80 surfactants were investigated.
Tween-series surfactants were selected because these surfactants increase cellulase activity during enzymatic hydrolysis and
do not inhibit cell growth in downstream fermentation processes. When surfactant was used in a pretreatment, a benefic effect
was expected in the enzymatic hydrolysis stage owing to surfactant carry-over from the pretreatment stage immediately upstream
of the hydrolysis. However, because it was necessary to wash the pretreated substrate with water to remove inhibitors produced
during pretreatment, no added benefit was obtained. When surfactant was used in the pretreatment only, it was found that it
had a marked effect on digestibility and that this effect was higher at lower enzyme loadings. Also, TW-80 was found to be
more effective than TW-20, and the addition of enzyme and TW-80 to substrate at the beginning of enzyme reaction was found
to most effectively increase digestibility. When TW-80 was added into either the pretreatment stage or the hydrolysis stage
the digestibilities of untreated sample increased by approx 40%, whereas an increase of only 45% was observed when TW-80 was
added to both stages. These results show that the addition of surfactant to either the pretreatment or the enzymatic hydrolysis
stage is sufficient to increase digestibility. 相似文献
992.
(Diacetoxyiodo)benzene (DIB) selectively oxidizes primary and secondary alcohols to the respective carbonyl compounds in the presence of RuCl3 (0.8-1.0 mol %) at room temperature in aqueous acetonitrile. This reaction proceeds via an initial instantaneous Ru-catalyzed disproportionation of DIB to iodobenzene and iodylbenzene with the latter acting as the actual stoichiometric oxidant toward alcohols. 相似文献
993.
Juae Kim Joo Young Shim Jihoon Lee Dal Yong Lee Sangmin Chae Jinwoo Kim Il Kim Hyo Jung Kim Sung Heum Park Hongsuk Suh 《Journal of polymer science. Part A, Polymer chemistry》2016,54(6):771-784
Polymers using new electron‐deficient units, 2‐pyriminecarbonitrile and 2‐fluoropyrimidine, were synthesized and utilized for the photovoltaics. Donor‐acceptor (D‐A) types of conjugated polymers ( PBDTCN, PBDTTCN, PBDTF, and PBDTTF ) containing 4,8‐bis(2‐octyldodecyloxy)benzo[1,2‐b;3,4‐b′]dithiophene (BDT) or 4,8‐bis(5‐(2‐octyldodecyloxy)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b′]dithiophene (BDTT) as electron rich unit and 2‐pyriminecarbonitrile or 2‐fluoropyrimidine as electron deficient unit were synthesized. We designed pyrimidine derivatives in which strong electron‐withdrawing group (C?N or fluorine) was introduced to the C2 position for the generation of strong electron‐deficient property. By the combination with the electron‐rich unit, the pyrimidines will provide low band gap polymers with low highest occupied molecular orbital (HOMO) energy levels for higher open‐circuit voltages (VOC). For the syntheses of the polymers, the electron‐rich and the electron‐deficient units were combined by Stille coupling reaction with Pd(0)‐catalyst. Absorption spectra of the thin films of PBDTTCN and PBDTTF with BDTT unit show shift to a longer wavelength region than PBDTCN and PBDTF with BDT unit. Four synthesized polymers provided low electrochemical bandgaps of 1.56 to 1.96 eV and deep HOMO energy levels between ?5.67 and ?5.14 eV. © 2015 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 771–784 相似文献
994.
The dynamics and stability of the high-speed fiber spinning process with spinline flow-induced crystallization and neck-like deformation have been studied using a simulation model equipped with governing equations of continuity, motion, energy, and crystallinity, along with the Phan-Thien–Tanner constitutive equation. Despite the fact that a simple one-phase model was incorporated into the governing equations to describe the spinline crystallinity, as opposed to the best-known two-phase model [Doufas et al. J Non-Newton Fluid Mech, 92:27–66, 2000a]; [Kohler et al. J Macromol Sci Phys, 44:185–202, 2005] that treats amorphous and crystalline phases separately in computing the spinline stress, the simulation has successfully portrayed the typical nonlinear characteristic of the high-speed spinning process called neck-like spinline deformation. It has been found that the criterion for the neck-like deformation to occur on the spinline is for the extensional viscosity to decrease on the spinline, so that the spinning is stabilized by the formation of the spinline neck-like deformation. The accompanying linear stability analysis explains this stabilizing effect of the spinline neck-like deformation, corroborating a recent experimental finding [Takarada et al. Int Polym Process, 19:380–387, 2004].This paper was presented at the 2nd Annual European Rheology Conference 2005 on April 21–23, 2005, in Grenoble, France. 相似文献
995.
In this work, the drag coefficient and the void fraction around a tube subjected to two-phase cross flow were studied for a single tube and for a tube placed in an array. The drag coefficients were determined by measuring the pressure distribution around the perimeter of the tube. Single tube drag data were taken when the tube was held both rigidly and flexibly. The test tube was made of acrylic and was 2.2 cm in diameter and 20 cm in length. In the experiments, liquid Reynolds number ranged from 430 to 21,900 for the single tube and liquid gap Reynolds number ranged from 32,900 and 61,600 for the tube placed in a triangular array. Free stream void fraction was varied from 0 to 0.4. At low Reynolds numbers, the ratio of two-phase to single-phase drag coefficient is found to be a strong function of εGr/Re2. However, at high Reynolds numbers only void fraction is the important parameter. Empirical correlations have been developed for the ratio of two-phase drag on a single tube and on a tube placed in an array. 相似文献
996.
We have designed and synthesized new anion receptors 1 and 2, which have amide NH, pyrrole NH and vinyl CH as hydrogen bond donors. These receptors are selective for dimethyl phosphinate and carboxylates. Due to electron withdrawing effect of the cyano group which is trans to the vinyl hydrogen with respect to carbon-carbon double bond, receptor 1 has higher binding constants for phosphinate and carboxylate than those of receptor 2. Modeling studies shows that cyano group polarized all three hydrogens through planar π-electron network. In addition, receptor 1 gave orange colored 1,4-addition product for cyanide. 相似文献
997.
Glucose‐induced and fructose‐induced deboronation reaction of 4‐mercaptophenylboronic acid assembled on silver investigated by surface‐enhanced Raman scattering 下载免费PDF全文
Nguyễn Hoàng Ly Anh Thu Ngoc Lam Nguyen Dinh Bao Young‐Je Kwark Sang Woo Joo 《Surface and interface analysis : SIA》2017,49(6):495-502
We examined the deboronation reaction of 4‐mercaptophenylboronic acid (4MPBA) via fructose and glucose on silver surfaces by means of surface‐enhanced Raman scattering (SERS) at the excitation wavelengths of 488, 514, and 633 nm. The SERS spectra on silver nanoparticles clearly exhibited specific spectral signatures of thiophenol (TP) peaks, indicating a deboronation reaction of 4MPBA on the surfaces, whereas no strong TP peaks were observed on gold nanoparticles. The vibrational bands at 417, 999, 1021, and 1574 cm?1 in the Ag SERS spectra could correspond to the in‐plane aromatic ring modes in TP. X‐ray photoelectron spectroscopy also supported the surface reaction on Ag by referring the B1s peaks at ~193 eV. The ratiometric Raman measurements of the band at 1574 cm?1, with respect to that at 1587 cm?1, revealed fructose and glucose quantification in the concentration range of 1–10 mm . We did not identify such changes for mannose, sucrose, and sialic acid. The SERS peaks of 4MPBA on roughened Ag plates also exhibited TP bands to show the time‐dependent spectral change. Our findings indicate that the deboronation of 4MPBA and conjugation with fructose and glucose may be facilitated efficiently on silver surfaces for their quantification. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
998.
House dust mites (HDM) are critical factors in airway inflammation. They activate respiratory epithelial cells to produce reactive oxygen species (ROS) and activate Toll-like receptor 4 (TLR4). ROS induce the expression of inflammatory cytokines in respiratory epithelial cells. Lycopene is a potent antioxidant nutrient with anti-inflammatory activity. The present study aimed to investigate whether HDM induce intracellular and mitochondrial ROS production, TLR4 activation, and pro-inflammatory cytokine expression (IL-6 and IL-8) in respiratory epithelial A549 cells. Additionally, we examined whether lycopene inhibits HDM-induced alterations in A549 cells. The treatment of A549 cells with HDM activated TLR4, induced the expression of IL-6 and IL-8, and increased intracellular and mitochondrial ROS levels. TAK242, a TLR4 inhibitor, suppressed both HDM-induced ROS production and cytokine expression. Furthermore, lycopene inhibited the HDM-induced TLR4 activation and cytokine expression, along with reducing the intracellular and mitochondrial ROS levels in HDM-treated cells. These results collectively indicated that the HDM induced TLR4 activation and increased intracellular and mitochondrial ROS levels, thus resulting in the induction of cytokine expression in respiratory epithelial cells. The antioxidant lycopene could inhibit HDM-induced cytokine expression, possibly by suppressing TLR4 activation and reducing the intracellular and mitochondrial ROS levels in respiratory epithelial cells. 相似文献
999.
The uncertainty evaluation based on ANOVA is discussed using the data in the example H.5 of the GUM. The example has shown the uncertainties of the results obtained on J = 10 days with K = 5 independent repeated observations for each day. Depending on whether a between-day effect exists or not, the two different equations have been involved in the uncertainty evaluation. Moreover, as expected from general statistical inference, the choice of the significance level in F-test may decide the existence of the effect. In this paper, F-tests on various J (j = 2, 3, …, 9 instead of 10) day observations at the 5 % significance level show inconsistent results for the existence of the between-day effect, as expected, which would force us to decide case by case which equation to employ. In order to avoid such conflicts, a metrological perspective approach is discussed under the intermediate precision condition of measurement. 相似文献
1000.
Dual Enzyme‐Triggered In Situ Crosslinkable Gelatin Hydrogels for Artificial Cellular Microenvironments 下载免费PDF全文
Bae Young Kim Yunki Lee Joo Young Son Kyung Min Park Ki Dong Park 《Macromolecular bioscience》2016,16(11):1570-1576
Horseradish peroxidase (HRP) and hydrogen peroxide (H2O2)‐mediated crosslinking reaction has become an attractive method to create in situ forming hydrogels. While the crosslinking system has been widely utilized, there are certain issues require improvement to extend their biomedical applications, including creation of stiff hydrogels without compromising cytocompatibility due to initially high concentrations of H2O2. A gelatin‐based hydrogels formed through a dual enzyme‐mediated crosslinking reaction using HRP and glucose oxidase (GOx) as an H2O2‐generating enzyme to gradually supply a radical source in HRP‐mediated crosslinking reaction is reported. The physicochemical properties can be controlled by varying enzyme concentrations. Furthermore the hydrogel matrices provide 3D microenvironments for supporting the growth and spreading of human dermal fibroblasts with minimized cytotoxicity, despite the cells being encapsulated within stiff hydrogels. These hydrogels formed with HRP/GOx have great potential as artificial microenvironments for a wide range of biomedical applications.