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971.
Salvador A. Snchez‐Tovar Alfredo Salazar‐Zazueta Baltasar Mena‐Iniesta Carmen Durn‐de‐Bazúa 《Starch - St?rke》2004,56(11):526-534
Mexicans staple food is maize “tortilla”, prepared by thermal‐alkaline processes. The sensory properties of “masa” and “tortilla” depend on the reactions occuring between lime and chemical compounds in maize. In the present study, the effect of different calcium hydroxide, Ca(OH)2, concentrations (0.0, 0.10, 0.30, 0.50 %, dry basis, d.b.) on the apparent viscosity and maximum gelatinization temperature of a cornstarch water slurry was assessed. This Mexican traditional thermal‐alkaline gelatinization reaction (TAGR) was evaluated in a Brabender Viscoamylograph. This small well‐mixed reactor was homogeneously heated, and apparent viscosity data from corn starch were recorded in Brabender Units BU). It was found that an increase in Ca(OH)2 concentrations considerably increases the apparent viscosity, thus reducing the time needed to reach the maximum gelatinization temperature. A mathematical model that represents the phenomena, that occur in the Viscoamylograph, was developed. In the model the Viscoamylograph was considered as a batch reactor and the apparent kinetic coefficients for the TAGR were obtained, including mass balances and thermal‐alkaline gelatinization rates, considering a spherical cornstarch granule formed by a starchy matrix. Activation energy found for this reaction was 1241 kJ. 相似文献
972.
Polymerization of lactide on monomethoxypolyoxyethylene (MPOE), using stannous octoate as a catalyst, was carried out in bulk and in solvent. Polymerization in a solvent permits one to work at a lower temperature and thus to prevent transesterification reactions. The copolymers synthesized in solvent exhibited a lower polydispersity and a polylactic acid (PLA) block longer and closer to the expected one. Therefore, this procedure was used to synthesize a series of diblock copolymers MPOE–D ,L -PLA, keeping the PLA chain constant (45,000 g/mol), the MPOE block increasing from 2000 to 5000, 10,000, 15,000, and 20,000 g/mol. The longer the MPOE chain, the higher the water uptake in the MPOE–PLA films and the lower the glass transition temperature of the copolymers. The synthesized copolymers were used to prepare microspheres by the double-emulsion method. The PLA microspheres possess a smooth surface, whereas those made from copolymers have a rough surface with irregularity increasing with the molecular weight of MPOE. The size of these microspheres depends on the amphiphilic nature of the copolymers, their hydrophilicity, and their intrinsic viscosity in the organic solvent. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1695–1702, 1998 相似文献
973.
Piet Van Mieghem Bart Steyaert Guido H. Petit 《International Journal of Communication Systems》1997,10(4):161-180
The throughput optimality of priority management strategies in a single buffer has been studied for a general aggregate arrival law. The tight upper bounds found are useful to understand optimality in the utilization of specific priority schemes such as push-out buffer (POB) and partial buffer sharing (PBS). This paper further focuses on the maximum allowable load ρmax versus the priority mix α for a PBS and a random push-out buffer (RPOB) of size K for a wide variety of arrival processes. The role of priorities in a special type of bursty arrivals, the compound Poisson process with constant burst length and random priority assignment within the burst is found to be less pronounced than that of ‘pure’ Poisson arrivals. On the other hand, the results for ON–OFF cell arrivals modelled by a MMPP(2), MMPP(3), and higher order Markov modulated processes (MMP) closely follow the behaviour of the maximum allowable load in the RPOB with Poisson arrivals, however, scaled to lower loads. The results indicate that the priority mix distribution within the aggregate arrival flow influences the shape of ρmax(α)-curve more than the aggregate arrival distribution itself. © 1997 John Wiley & Sons, Ltd. 相似文献
974.
975.
E. Sánchez E. Bannier V. Cantavella M.D. Salvador E. Klyatskina J. Morgiel J. Grzonka A.R. Boccaccini 《Journal of Thermal Spray Technology》2008,17(3):329-337
Al2O3-13%TiO2 coatings were deposited on stainless steel substrates from conventional and nanostructured powders using atmospheric plasma
spraying (APS). A complete characterization of the feedstock confirmed its nanostructured nature. Coating microstructures
and phase compositions were characterized using SEM, TEM, and XRD techniques. The microstructure comprised two clearly differentiated
regions. One region, completely fused, consisted mainly of nanometer-sized grains of γ-Al2O3 with dissolved Ti+4. The other region, partly fused, retained the microstructure of the starting powder and was principally made up of submicrometer-sized
grains of α-Al2O3, as confirmed by TEM. Coating microhardness as well as tribological behavior were determined. Vickers microhardness values
of conventional coatings were in average slightly lower than the values for nanostructured coating. The wear resistance of
conventional coatings was shown to be lower than that of nanostructured coatings as a consequence of Ti segregation. A correlation
between the final properties, the coating microstructure, and the feedstock characteristics is given. 相似文献
976.
977.
Carmen Almodvar-Pay Maria Guardiola-Ripoll Maria Giralt-Lpez Carme Gallego Pilar Salgado-Pineda Salvador Miret Raymond Salvador María J. Muoz Luisa Lzaro Amalia Guerrero-Pedraza Mara Parellada María I. Carrin Manuel J. Cuesta Teresa Maristany Salvador Sarr Lourdes Faans Luis F. Callado Brbara Arias Edith Pomarol-Clotet Mar Fatj-Vilas 《International journal of molecular sciences》2022,23(13)
Included in the neurotrophins family, the Neuritin 1 gene (NRN1) has emerged as an attractive candidate gene for schizophrenia (SZ) since it has been associated with the risk for the disorder and general cognitive performance. In this work, we aimed to further investigate the association of NRN1 with SZ by exploring its role on age at onset and its brain activity correlates. First, we developed two genetic association analyses using a family-based sample (80 early-onset (EO) trios (offspring onset ≤ 18 years) and 71 adult-onset (AO) trios) and an independent case–control sample (120 healthy subjects (HS), 87 EO and 138 AO patients). Second, we explored the effect of NRN1 on brain activity during a working memory task (N-back task; 39 HS, 39 EO and 39 AO; matched by age, sex and estimated IQ). Different haplotypes encompassing the same three Single Nucleotide Polymorphisms(SNPs, rs3763180–rs10484320–rs4960155) were associated with EO in the two samples (GCT, TCC and GTT). Besides, the GTT haplotype was associated with worse N-back task performance in EO and was linked to an inefficient dorsolateral prefrontal cortex activity in subjects with EO compared to HS. Our results show convergent evidence on the NRN1 association with EO both from genetic and neuroimaging approaches, highlighting the role of neurotrophins in the pathophysiology of SZ. 相似文献
978.
Mnica Canales Juan Manuel Ramírez-de-Arellano Juan Salvador Arellano Luis Fernando Magaa 《International journal of molecular sciences》2022,23(9)
Using DFT simulations, we studied the interaction of a semifullerene C30 and a defected graphene layer. We obtained the C30 chemisorbs on the surface. We also found the adsorbed C30 chemisorbs, Li, Ti, or Pt, on its concave part. Thus, the resulting system (C30-graphene) is a graphene layer decorated with a metal-doped C30. The adsorption of the molecules depends on the shape of the base of the semifullerene and the dopant metal. The CO molecule adsorbed without dissociation in all cases. When the bottom is a pentagon, the adsorption occurs only with Ti as the dopant. It also adsorbs for a hexagon as the bottom with Pt as the dopant. The carbon dioxide molecule adsorbs in the two cases of base shape but only when lithium is the dopant. The adsorption occurs without dissociation. The ozone molecule adsorbs on both surfaces. When Ti or Pt are dopants, we found that the O3 molecule always dissociates into an oxygen molecule and an oxygen atom. When Li is the dopant, the O3 molecule adsorbs without dissociation. Methane did not adsorb in any case. Calculating the recovery time at 300 K, we found that the system may be a sensor in several instances. 相似文献
979.
A.De Luca M.Odorico G.Salvador 《钢铁》2006,41(1):85-86
介绍了达涅利摩加沙玛公司设计并成功投产的新一代高速切头剪,该切头剪具有优化剪切功能,起到了优化线材生产线操作和减少设定停车时间的作用. 相似文献
980.
García-Gómez JM Luts J Julià-Sapé M Krooshof P Tortajada S Robledo JV Melssen W Fuster-García E Olier I Postma G Monleón D Moreno-Torres A Pujol J Candiota AP Martínez-Bisbal MC Suykens J Buydens L Celda B Van Huffel S Arús C Robles M 《Magma (New York, N.Y.)》2009,22(1):5-18
Justification Automatic brain tumor classification by MRS has been under development for more than a decade. Nonetheless, to our knowledge,
there are no published evaluations of predictive models with unseen cases that are subsequently acquired in different centers.
The multicenter eTUMOUR project (2004–2009), which builds upon previous expertise from the INTERPRET project (2000–2002) has
allowed such an evaluation to take place.
Materials and Methods A total of 253 pairwise classifiers for glioblastoma, meningioma, metastasis, and low-grade glial diagnosis were inferred
based on 211 SV short TE INTERPRET MR spectra obtained at 1.5 T (PRESS or STEAM, 20–32 ms) and automatically pre-processed.
Afterwards, the classifiers were tested with 97 spectra, which were subsequently compiled during eTUMOUR.
Results In our results based on subsequently acquired spectra, accuracies of around 90% were achieved for most of the pairwise discrimination
problems. The exception was for the glioblastoma versus metastasis discrimination, which was below 78%. A more clear definition
of metastases may be obtained by other approaches, such as MRSI + MRI.
Conclusions The prediction of the tumor type of in-vivo MRS is possible using classifiers developed from previously acquired data, in
different hospitals with different instrumentation under the same acquisition protocols. This methodology may find application
for assisting in the diagnosis of new brain tumor cases and for the quality control of multicenter MRS databases. 相似文献