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11.
Anna Siskova Jan Kral Jana Drabova Klara Cervena Kristyna Tomasova Jiri Jungwirth Tomas Hucl Pavel Kohout Sandra Summerova Ludmila Vodickova Pavel Vodicka Veronika Vymetalkova 《International journal of molecular sciences》2022,23(14)
A colorectal adenoma, an aberrantly growing tissue, arises from the intestinal epithelium and is considered as precursor of colorectal cancer (CRC). In this study, we investigated structural and numerical chromosomal aberrations in adenomas, hypothesizing that chromosomal instability (CIN) occurs early in adenomas. We applied array comparative genomic hybridization (aCGH) to fresh frozen colorectal adenomas and their adjacent mucosa from 16 patients who underwent colonoscopy examination. In our study, histologically similar colorectal adenomas showed wide variability in chromosomal instability. Based on the obtained results, we further stratified patients into four distinct groups. The first group showed the gain of MALAT1 and TALAM1, long non-coding RNAs (lncRNAs). The second group involved patients with numerous microdeletions. The third group consisted of patients with a disrupted karyotype. The fourth group of patients did not show any CIN in adenomas. Overall, we identified frequent losses in genes, such as TSC2, COL1A1, NOTCH1, MIR4673, and GNAS, and gene gain containing MALAT1 and TALAM1. Since long non-coding RNA MALAT1 is associated with cancer cell metastasis and migration, its gene amplification represents an important event for adenoma development. 相似文献
12.
Epoxy/poly(ɛ‐caprolactone) nanocomposites: Effect of transformations of structure on crystallization
Jaroslav Kratochvíl Jakub Rotrekl Ludmila Kaprálková Jiřina Hromádková Ivan Kelnar 《应用聚合物科学杂志》2013,130(5):3197-3204
The influence of morphology of the epoxy/poly(?‐caprolactone) (PCL) system and corresponding nanocomposites with organophilized layered silicate on PCL crystallization was studied by differential scanning calorimetry, scanning, and transmission electron microscopy. The results obtained indicate a significant affecting of nonisothermal PCL crystallization by phase morphology brought about by the reaction‐induced phase separation (RIPS) influenced either by various nanoclay contents or the epoxy/PCL ratio. Dispersed morphology of PCL matrix with epoxy globules induces crystallization at higher temperatures. The inverse dispersed morphology of epoxy matrix with PCL inclusions causes crystallization at lower temperature. The co‐continuous morphology induces crystallization in both steps. Rate of the second crystallization step is substantially higher than that in the first step. No nucleation effect has been found in the nanocomposites with the added nanofiller. Multicomponent samples show retarded crystallization, i.e., lower crystallinities and lower overall crystallization rate compared with neat PCL. The results obtained suggest that it is primarily morphological/interfacial effects that play a decisive role in the crystallization behavior of PCL in the epoxy/PCL/clay system. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3197–3204, 2013 相似文献
13.
Muhammad G. Dastgir Ludmila G. Peeva Andrew G. Livingston 《Chemical engineering science》2005,60(24):7034-7044
This study investigates the possibility of using a composite-supported polymeric liquid membrane (CSPLM) configuration for the Membrane Aromatic Recovery System (MARS). The membrane was prepared by impregnating the liquid membrane phase into the pores of a composite flat sheet membrane consisting of a microporous support and a thin non-porous layer. A polyvinylidenfluoride (PVDF) microporous support coated with a thin non-porous polydimethylsiloxane (PDMS) layer was chosen as a composite membrane due to its superior combination of mass transfer rates and chemical resistance among the membranes tested and polypropylene glycol (PPG) was used as a liquid membrane phase due to its high affinity for phenol. The resulting membrane showed uniform selectivity and operational stability under the continuous MARS operating conditions for more than two months. The mass transfer rates () were 5 times higher than those of the silicone rubber tubing () which is used in commercial scale MARS technology. The CSPLM also exhibited reduced water flux and low sodium ion transfer. The partition coefficient of phenol between PPG/water was measured as 84. A marked effect of ionic strength on partition coefficient of phenol was observed with partition coefficient increase to 134 when measured in the presence of 20 wt% KCl in phenol aqueous solution. 相似文献
14.
The cationic polymerization of cyclopentadiene (CPD) with 1-(4-methoxyphenyl)ethanol (1)/BF3OEt2 initiating system in CH2Cl2:CH3CN 4:1 (v/v) mixture at room temperature and in the presence of water ([H2O]/[BF3OEt2] up to 8) is reported. The number-average molecular weights of obtained polymers increased in direct proportion to monomer conversion or initial monomer concentration (M n ≤ 4,000 g mol−1) in agreement with calculated values, and were inversely proportional to initiator concentration. Polymer MWDs were relatively narrow (M w/M n = 1.4–1.7) up to 60% of monomer conversion. It was also shown that regioselectivity of CPD polymerization with 1/BF3OEt2 initiating system did not depend significantly on water, monomer, or initiator concentration (1,4-structures content was nearly 60% in all cases). 相似文献
15.
A commercial crosslinked ionic polymer AV‐17 containing ? N(CH3)3Cl groups was used. The common compounds of Bi(III) and Al(III); Bi(III) and Cr(III); Bi(III) and Fe(III); Bi(III) and FeOOH and of three components—Bi(III), Fe(III), and Cr(III); Bi(III), FeOOH, and Cr(III) were obtained in the AV‐17 polymer phase and investigated using scanning electron microscopy, powder X‐ray diffraction, thermogravimetric analysis, and Fourier‐transform infrared spectroscopy. It was shown that metal‐containing compounds were concentrated on the surface of the polymer granules. The compounds were in the crystalline (BiOCl) or amorphous (jarosites and oxihydroxides) state. The morphology and composition of the metal‐containing ultra dispersed particles were different on the surface and in the volume of the polymer granule. Most of the metal‐containing compounds were in the form of pseudo spherical particles, but compounds containing Bi(III) and FeOOH in the volume of AV‐17 granule, were in the form of clew of nanometer fibers. Thermogravimetric analysis (in an N2 atmosphere) in the range 24–1000°C of the metallic compounds containing polymer was also carried out. The metal‐containing polymer samples were stable up to 120°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
16.
Investigating the Role of Conformational Effects on Laccase Stability and Hyperactivation under Stress Conditions 下载免费PDF全文
Dr. Valerio Ferrario Dr. Alexey Chernykh Federica Fiorindo Dr. Marina Kolomytseva Dr. Loris Sinigoi Dr. Nina Myasoedova Dr. Diana Fattor Prof. Dr. Cynthia Ebert Prof. Dr. Ludmila Golovleva Prof. Dr. Lucia Gardossi 《Chembiochem : a European journal of chemical biology》2015,16(16):2365-2372
Fungal laccase from Steccherinum ochraceum 1833 displays remarkable stability under different harsh conditions: organic/buffer mixtures, thermal treatment, and microwave radiation. The behavior is particularly significant in the light of the sharp inactivation observed for two different fungal laccases. Laccase from S. ochraceum 1833 also displays hyperactivation under mild thermal treatment (60 °C). Molecular dynamics simulations at 80 °C explained how this laccase retains the geometry of the electron transfer pathway, thereby assuring electron transfer through the copper ions and thus maintaining its catalytic activity at high temperature. Spectroscopic studies revealed that the thermal activation corresponds to specific conformational changes in the protein. The results indicate that this laccase is potentially applicable under denaturing conditions that might be beneficial for the biotransformation of recalcitrant substrates. 相似文献
17.
Ivan Kelnar Ivan Fortelný Ludmila Kaprálková Jiřina Hromádková 《Polymer Engineering and Science》2015,55(9):2133-2139
Effect of layered silicates on structure of microfibrillar composites (MFCs) with reinforcing PA6 fibrils formed in situ by melt drawing was studied. Clay was added to HDPE/PA6 MFC using different mixing protocols including simultaneous addition, application of pre‐made masterbatches with both constituents and their combinations. In all cases, majority of nanofiller (NF) was contained inside PA6 fibrils. On the other hand, fibrils dimensions were significantly affected by the clay addition protocol; their marked increase in the case of simultaneous addition of all components and application of HDPE/C30 nanocomposite indicate important effect of NF migration to the PA6 phase in the course of mixing and melt drawing. The effect of properties of PA6 and HDPE phases and NF migration on the morphology evolution is discussed. It is shown that the fiber shape and volume after sample drawing are controlled by the interplay between the dispersed fibril extension and coalescence. POLYM. ENG. SCI., 55:2133–2139, 2015. © 2015 Society of Plastics Engineers 相似文献
18.
Sergei V. Kostjuk Alexei Yu. Dubovik Irina V. Vasilenkol Vyacheslav P. Mardykin Ludmila V. Gaponik Fyodor N. Kaputsky Lev M. Antipin 《Polymer Bulletin》2004,52(3-4):227-234
Summary
Quasiliving cationic polymerization of styrene was obtained in the system 2-phenyl-2-propano-/AlCl3·OBu2/Bu2O in a mixture of 1,2-dichloroethane and n-hexane (55:45 viv) at -15 °C. The molecular weights of the polymers (Mn) increased in direct proportion to the monomer conversion. However, the experimental Mns are essentially higher than theoretical ones, indicating that slow initiation relative to propagation takes place. The molecular weight distributions were broad (Mw/Mn2.5), probably due to the slow initiation and slow exchange between reversibly terminated and propagating species. 相似文献
19.
Yulia S Petrova Elena I Kapitanova Ludmila K Neudachina Alexandr V Pestov 《分离科学与技术》2017,52(15):2385-2394
The scope of work is to study the mutual influence of metal ions during their sorption by sulfoethylated chitosan. The sorption isotherms of metal ions from single- and multi-component solutions are obtained. The sorption capacity of the sorbent towards Ag(I) and Cu(II) is revealed to be 1.63 and 1.41 mmol/g in single-, and 1.40 and 0.85 mmol/g in five-component solution. By comparing the affinity parameter and capacity of sulfoethylated chitosan towards ions in single- and multi-component solutions, it is concluded that Ag(I) and Cu(II) ions suppress the sorption of cobalt(II), nickel(II), zinc(II), cadmium(II), magnesium(II), calcium(II), strontium(II), barium(II), manganese(II) and lead(II). 相似文献
20.
Yulia?A.?Piskun Irina?V.?Vasilenko Ludmila?V.?Gaponik Sergei?V.?KostjukEmail author 《Polymer Bulletin》2012,68(6):1501-1513
The activated anionic ring-opening polymerization of ε-caprolactam initiated by 0.35 mol% of combined initiator, i.e., equimolar
mixture of magnesium di(ε-caprolactamate) (CL2Mg) with magnesium halides (MgCl2, MgBr2, and MgI2) as well as of ε-caprolactam magnesium bromide (CLMgBr) in the presence of 0.35 mol% of N-acetyl-ε-caprolactam as an activator has been investigated in the temperature range 140–200 °C. It was found that the reaction
rate increased while the apparent activation energy decreased in the following series: CL2Mg/MgCl2 < CL2Mg/MgBr2 ~ CLMgBr < CL2Mg/MgI2. In addition, the poly(ε-caprolactam)s prepared with CL2Mg/MgX2 (MgX2 = MgCl2, MgBr2, and MgI2) are characterized by slightly higher thermal stability than polymers obtained with CLMgBr as initiator. These observations
were explained in terms of the coordination of Lewis acids (MgX2, where X = Cl, Br, and I) with imide carbonyl of N-acyllactam end groups leading to the increase of their reactivity and stability. 相似文献