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131.
Maurizio?ServiliEmail author Roberto?Selvaggini Agnese?Taticchi Sonia?Esposto Gianfrancesco?Montedoro 《Journal of the American Oil Chemists' Society》2003,80(7):685-695
The time of exposure of olive pastes to air contact (TEOPAC) during malaxation was studied as a processing parameter that
could be used to control endogenous oxidoreductases, such as polyphenoloxidase, peroxidase, and lipoxygenase, which affect
virgin olive oil quality. Phenolic and volatile compounds were analyzed in the oils obtained using progressive TEOPAC at three
ripening stages of olives. Multivariate statistical analysis was applied to the raw data. The phenolic concentration of virgin
olive oil progressively decreased with increasing IEOPAC. On the contrary, a positive relationship was found with the concentration
of several volatile compounds responsible for virgin olive oil aroma. The effect of TEOPAC, however, was strictly related
to fruit ripening. 相似文献
132.
A commonly used nylon 6 two‐step VK tubular reactor is simulated in this work. To verify the reliability of the model, careful comparison with results obtained on different continuous plants is made. The effect of various conditions and parameters, e.g. feed composition, temperature, pressure, etc. on the product properties such as caprolactam conversion, degree of polymerization (DP), dimer, integral heat and their distribution index is studied. It is observed that the caprolactam conversion and DP of the product may be affected by various conditions in the first stage and the temperature profile at the top of the second stage, but they finally reach the equilibrium values if the residence time is long enough. The most effective way to increase DP of the product is to increase the vacuum at the top of the second stage.
133.
Laura de Andrade Souza Denise Ramos Moreira Nágila Maria Pontes Silva Ricardo Martin Edmund Maier Paulo Roberto Campos Flexa Ribeiro Filho Francisco Murilo Tavares Luna Cesar Liberato Petzhold 《Journal of the American Oil Chemists' Society》2023,100(2):175-184
Vegetable oils are very promising alternatives to fossil lubricants due to their abundance, low cost, excellent performance, and environmental friendliness. Due to its multifunctional structure, castor oil is an excellent precursor in the synthesis of new biolubricants. However, it showed poor thermal-oxidative stability and a higher pour point. This study used castor oil fatty acids prepared by transesterification (EHRO), epoxidation (TEPO), and oxirane ring opening with the aromatic amines aniline (ANIL) and p-anisidine (ANIS). The chemical structure of these oils was verified by 1H and 13C NMR analysis, and mass spectrometry. Measurements show that the presence of an aromatic amine increases the viscosity resulting in 172 (ANIL) and 199 (ANIS) cSt at 40°C, but reduces viscosity index to 16 and 1, respectively. In addition, the amine groups can scavenge radicals increasing their thermal and oxidative stability. These products do not oxidize copper, and tribological analysis reveals that ANIS has the lowest torque with wear equivalent to commercial mineral lubricant NH-140. 相似文献
134.
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136.
Pier Roberto Danesi 《溶剂提取与离子交换》2013,31(6):741-757
Abstract In this article, the results of the application of a boron removal treatment based on a process of chemosorption on liquid waste of urban, agricultural, or industrial origin is presented. The isotherms of the process have been established and a study of the influence of the different variables in the tests in columns has been carried out. The results obtained indicate that the process of chemosorption shows strongly favorable isotherms, and moreover it is notably influenced by the variable “flow rate,” making the breakthrough point appear earlier and the curves move towards the left. However, important differences in the curves for the variable “dimensions of the bed” have not been observed. Furthermore, a pH‐dependent mechanism for the treatment process of boronated effluents by means of chemosorption with the specific Amberlite IRA-743 resin was developed. According to breakthrough point data, experimentally achieved in elution tests for the maximum value allowed by environmental legislation, of 3 mg B L?1, a double mechanism is proposed. It can be suggested that for basic pH the mechanism corresponds to stereospecific reactivity between the borate ion and hydroxide groups of the N‐methylglucamine active site of the resin in cis‐position, a maximum appearing between pH 8.5 and 9.5, corresponding to borate ion predominance. On the other hand, a mechanism based on the hydrogen bridge bond formation reaction between the ionized amino group of the resin and boric acid is suggested for neutral and slightly acid pH. This last reaction differentiates this resin from the other absorbents used for boron removal in industrial wastes, such as metallic oxides, clays, humic acids, and so on. 相似文献
137.
Antonio Mancini Sebastiano Raimondo Chantal Di Segni Mariasara Persano Giovanni Gadotti Andrea Silvestrini Roberto Festa Luca Tiano Alfredo Pontecorvi Elisabetta Meucci 《International journal of molecular sciences》2013,14(12):23893-23909
In previous works we demonstrated an inverse correlation between plasma Coenzyme Q10 (CoQ10) and thyroid hormones; in fact, CoQ10 levels in hyperthyroid patients were found among the lowest detected in human diseases. On the contrary, CoQ10 is elevated in hypothyroid subjects, also in subclinical conditions, suggesting the usefulness of this index in assessing metabolic status in thyroid disorders. A Low-T3 syndrome is a condition observed in several chronic diseases: it is considered an adaptation mechanism, where there is a reduction in pro-hormone T4 conversion. Low T3-Syndrome is not usually considered to be corrected with replacement therapy. We review the role of thyroid hormones in regulation of antioxidant systems, also presenting data on total antioxidant capacity and Coenzyme Q10. Published studies suggest that oxidative stress could be involved in the clinical course of different heart diseases; our data could support the rationale of replacement therapy in low-T3 conditions. 相似文献
138.
Roberto Rosa Paolo Veronesi Shahoua Han Valentina Casalegno Milena Salvo Elena Colombini Cristina Leonelli Monica Ferraris 《Journal of the European Ceramic Society》2013,33(10):1707-1719
Microwaves at 2.45 GHz have been applied to ignite the combustion synthesis of compacted Ti–Si–C powders mixtures, having 1:1:1 atomic ratio, in order to join SiC-based components. A mixture of different refractory phases such as TiC and TiSi2 were obtained. Depending on the synthesis conditions, no residual silicon in the joint was detected, suggesting the suitability of the here proposed experimental joining approach for nuclear plants and high temperature applications. A simplified model was developed with the aim of obtaining a deeper understanding of the here proposed rapid, almost pressure-less and localized heating joining method. Experimental and numerical simulation results demonstrate that joining of SiC can be rapidly obtained with minimization of heat affected zones in the SiC substrates. Maximum apparent shear strength values of the joints ranged from 9.9 to 45.1 MPa, depending on the process conditions. 相似文献
139.
Cecilia Ramírez Adriana Saldaña Berenice Hernández Roberto Acero Ricardo Guerra Sergi Garcia-Segura Enric Brillas Juan M. Peralta-Hernández 《Journal of Industrial and Engineering Chemistry》2013,19(2):571-579
Solutions of methyl orange azo dye were degraded by electrochemical oxidation using a 3 L flow plant with a boron-doped diamond (BDD)/stainless steel cell operating at constant current density, ambient temperature and liquid flow rate of 12 L min?1. A 23 factorial design considering the applied current density, azo dye concentration and electrolysis time as variable independents was used to analyze the process by response surface methodology. LC–MS analysis revealed the formation of seven oxidation products from the cleavage of the NN group of the dye, followed by deamination, formation of a nitro group and/or desulfonation of the resulting aromatics. 相似文献
140.