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11.
Th. Bartsch D. Sonnenberg Ch. Strelow Ch. Heyn W. Hansen 《Journal of Electronic Materials》2014,43(6):1972-1975
We studied the electrical transport through epitaxial, 8 nm long and about 100 nm diameter, GaAs pillars. They are fabricated with molecular beam epitaxy using a self-assembling method called local droplet etching. The nanopillars are embedded in an AlGaAs tunneling barrier between two epitaxial GaAs layers. Because of the epitaxial growth, the pillars are connected to these GaAs layers without additional interfaces. They thus can be considered as electronic point contacts between three-dimensional electron reservoirs. Voltage-current characteristics of the structures feature a characteristic asymmetry that is not observed in reference samples. Furthermore, the behavior of the resistance in magnetic fields applied parallel and perpendicular to the current direction is compared for samples with and without pillars. Clear differences are found that are associated with current-carrying states in the pillars. 相似文献
12.
Md Azimul Haque Appala Naidu Gandi Rajeshkumar Mohanraman Yakui Weng Bambar Davaasuren Abdul‐Hamid Emwas Craig Combe Derya Baran Alexander Rothenberger Udo Schwingenschlgl Husam N. Alshareef Shuai Dong Tom Wu 《Advanced functional materials》2019,29(13)
Organic–inorganic hybrid materials are of significant interest owing to their diverse applications ranging from photovoltaics and electronics to catalysis. Control over the organic and inorganic components offers flexibility through tuning their chemical and physical properties. Herein, it is reported that a new organic–inorganic hybrid, [Mn(C2H6OS)6]I4, with linear tetraiodide anions exhibit an ultralow thermal conductivity of 0.15 ± 0.01 W m?1 K?1 at room temperature, which is among the lowest values reported for organic–inorganic hybrid materials. Interestingly, the hybrid compound has a unique 0D structure, which extends into 3D supramolecular frameworks through nonclassical hydrogen bonding. Phonon band structure calculations reveal that low group velocities and localization of vibrational energy underlie the observed ultralow thermal conductivity, which could serve as a general principle to design novel thermal management materials. 相似文献
13.
Erkan Aydin Michele De Bastiani Xinbo Yang Muhammad Sajjad Faisal Aljamaan Yury Smirnov Mohamed Nejib Hedhili Wenzhu Liu Thomas G. Allen Lujia Xu Emmanuel Van Kerschaver Monica Morales‐Masis Udo Schwingenschlgl Stefaan De Wolf 《Advanced functional materials》2019,29(25)
Parasitic absorption in transparent electrodes is one of the main roadblocks to enabling power conversion efficiencies (PCEs) for perovskite‐based tandem solar cells beyond 30%. To reduce such losses and maximize light coupling, the broadband transparency of such electrodes should be improved, especially at the front of the device. Here, the excellent properties of Zr‐doped indium oxide (IZRO) transparent electrodes for such applications, with improved near‐infrared (NIR) response, compared to conventional tin‐doped indium oxide (ITO) electrodes, are shown. Optimized IZRO films feature a very high electron mobility (up to ≈77 cm2 V?1 s?1), enabling highly infrared transparent films with a very low sheet resistance (≈18 Ω □?1 for annealed 100 nm films). For devices, this translates in a parasitic absorption of only ≈5% for IZRO within the solar spectrum (250–2500 nm range), to be compared with ≈10% for commercial ITO. Fundamentally, it is found that the high conductivity of annealed IZRO films is directly linked to promoted crystallinity of the indium oxide (In2O3) films due to Zr‐doping. Overall, on a four‐terminal perovskite/silicon tandem device level, an absolute 3.5 mA cm?2 short‐circuit current improvement in silicon bottom cells is obtained by replacing commercial ITO electrodes with IZRO, resulting in improving the PCE from 23.3% to 26.2%. 相似文献
14.
Carrier lifetimes were measured in epitaxial silicon layers which were deposited on silicon wafers implanted with different nitrogen doses at 330 keV. At doses greater than 1016 cm-2 the lifetime was more than one order of magnitude higher on the implanted part of the wafers (~300?s). The mechanism responsible for this effect is connected with the gettering efficiency for heavy metals of a precipitation-rich dislocation network in the implanted silicon. 相似文献
15.
Jürgen K. P. Weder Udo Scharf 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1981,172(3):185-189
Summary Fingerprinting (thin-layer electrophoresis/chromatography) after tryptic or chymotryptic digestion of performic acid-oxidized monomeric, dimeric, and oligomeric ribonuclease isolated from heated ribonuclease and monomeric unheated ribonuclease demonstrates one additional peptide in all heated samples. Preparative ion-exchange chromatography of the tryptic digests results in the corresponding number of fractions, 15 and 14, respectively. Amino acid analysis andN-terminal amino acid determination relate most of these peptides to theoretical tryptic peptides, whilst some are formed by further fragmentation due to chymotryptic activity of the commercial TPCK-trypsin used. This is also true of the additional peptide found in heated samples. So no distinct crosslinking peptide could be demonstrated. Only favoured participation of theN-terminal region in crosslinking is indicated. The observed differences between heated and unheated samples must be due to differences in three-dimensional structure leading to differences in susceptibility for proteolytic enzymes. Demonstration of both isopeptides, aspartyllysine and glutamyllysine, in three out of five fractions from digests of ribonuclease dimer, indicating six different isopeptide crosslinks, confirms the assumption of a very unspecific formation of crosslinks during protein heating.
We thank the Deutsche Forschungsgemeinschaft for supporting this work and Mrs. Anneliese Mödl and Mrs. Angelika Langwieser for performing the amino acid analyses 相似文献
Modelluntersuchungen über das Erhitzen von Lebensmittelproteinen —Oligomerisierung von Ribonuclease beim ErhitzenIII. Über die Lokalisierung säurelabiler Brückenpeptide
Zusammenfassung Durch zweidimensionale Dünnschichtelektrophorese/-chromatographie nach tryptischer oder chymotryptischer Spaltung perameisensäureoxidierter monomerer, dimerer und oligomerer Ribonuclease aus erhitzter Ribonuclease sowie monomerer unerhitzter Ribonuclease wurde ein zusätzliches Peptid in allen erhitzten Proben nachgewiesen. Durch präparative Ionenaustauscherchromatographie tryptischer Hydrolysate wurden dementsprechend 15 bzw. 14 Fraktionen erhalten. Durch Aminosäureanalyse und Bestimmung derN-terminalen Aminosäuren konnten die meisten Peptide theoretischen tryptischen Spaltpeptiden zugeordnet werden, während einige durch weitergehende Spaltung aufgrund chymotryptischer Nebenaktivitäten im verwendeten TPCK-Trypsinpräparat gebildet werden. Dies gilt auch für das in erhitzten Proben zusätzlich gefundene Peptid, so daß kein spezifisches Brückenpeptid nachgewiesen werden konnte. Lediglich eine bevorzugte Beteiligung desN-terminalen Bereiches an Quervernetzungsreaktionen ist erkennbar. Die beobachteten Unterschiede zwischen erhitzten und unerhitzten Proben beruhen auf unterschiedlicher räumlicher Anordnung, die zu Unterschieden in der Zugänglichkeit für proteolytische Enzyme führt. In drei von fünf untersuchten Fraktionen tryptisch gespaltener dimerer Ribonuclease konnten jeweils beide Isopeptide, Aspartyl-lysin und Glutamyl-lysin, also insgesamt sechs verschiedene Isopeptidbrücken nachgewiesen werden. Damit wird die Annahme einer sehr unspezifischen Brückenbildung während der Proteinerhitzung bestätigt.
We thank the Deutsche Forschungsgemeinschaft for supporting this work and Mrs. Anneliese Mödl and Mrs. Angelika Langwieser for performing the amino acid analyses 相似文献
16.
17.
K. Gustav U. Bartsch H. Schütz R. Machinek W. Lüttke 《Advanced Synthesis \u0026amp; Catalysis》1991,333(1):101-105
Spectroscopic Investigations on Organic Carbonyl Compounds. VI. N.M.R.-Studies on Substituted β;-Diketones and their Vinyloge Derivatives . 13C- and 1H-n.m.r.-data of substituted β-diketones and their vinyloge derivatives are presented. Most of the compounds exist chiefly in the enol-form. Only in the case of 4-dimethyl-aminodibenzoylmethane a keto-enol-equilibrium is registered. The influence of the substituent A and the chainlength on the position of the enol proton is discussed. 相似文献
18.
The real toughness response of RPV material can only be determined after the final shut down of the NPP. Such a chance is given now by investigating material from the former Greifswald NPP (VVER-440/230).In the first part the paper deals with fast neutron fluence calculations and retrospective dosimetry based on Niobium. Unfortunately, a second neutron reaction besides 93Nb(n,n’) leading to 93mNb-activity is the reaction 92Mo(n,γ)93Mo. Based on the found Nb and Mo contents in the RPV material, it turned out that the 93mNb generation on the Mo path mostly dominates over the fast neutron induced generation from Nb.The comparison between the calculated and the measured 93mNb activities typically resulted in deviations of 50%. Possible reasons for the observed differences are discussed.In the second part first results of fracture mechanic investigations are reported. SE(B) specimens from three thickness positions were tested and evaluated according to the test standard ASTM E1921-05. Cleavage fracture toughness values, KJc, were determined and Master Curve based reference temperatures (T0) were evaluated. The T0 measured at the inner surface of the RPV did not represent the conservative condition. The T0 of disc 1-1.3 located between the surface and 1/4 thickness is about 40K higher compared with those of the surface.The measured KJc values are not enveloped by the 5% fractile indexed with T0 according to the Master Curve concept. However, the 5% fractile indexed with the VERLIFE reference temperature RTTo that includes an additional margin envelops the measured KJc values. Therefore the VERLIFE lower bound curve conservatively describes the fracture toughness of the investigated weld metal. 相似文献
19.
L. T. Phong J. J. Stoorvogel M. E. F. van Mensvoort H. M. J. Udo 《Nutrient Cycling in Agroecosystems》2011,90(1):33-49
This study quantifies soil nutrient balances of Integrated Agriculture-Aquaculture Systems in the Mekong Delta of Vietnam.
Eleven farms were monitored to collect data on farm activities and nutrient inputs and outputs to compute these balances of
the rice-based and high input fish system in O Mon district (R-HF); the rice-based and medium input fish system in Tam Binh
district (R-MF); and the orchard-based and low input fish system in Cai Be district (O-LF). For the estimation, the Nutmon
model has been adapted to the specific conditions in these integrated systems in Asia (Nutmon-Asia). New regression models
of leaching and gaseous losses of nitrogen were applied to fields used for upland crops and paddy rice. Reference values were
used for the assessment of nitrogen fixation in paddy soils, wet atmospheric deposition, and irrigation water. The results
showed that farms in all three systems have nitrogen, phosphorus and potassium surpluses (84 kg N, 73 kg P, and 69 kg K ha−1 year−1). The O-LF system had the smallest nitrogen surplus while the smallest surplus of phosphorus and potassium was seen in the
R-HF system. High surpluses of phosphorus and potassium were found in vegetable fields, whereas a negative potassium balance
was found in the rice fields of all three systems. The positive farm nutrient balances indicate that it is likely that soil
fertility will be maintained although there is a risk for environmental contamination. 相似文献
20.