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排序方式: 共有909条查询结果,搜索用时 15 毫秒
901.
Osiris A. Valdez Banda Floris GoerlandtJakub Montewka Pentti Kujala 《Accident; analysis and prevention》2015
Winter navigation is a complex but common operation in north-European sea areas. In Finnish waters, the smooth flow of maritime traffic and safety of vessel navigation during the winter period are managed through the Finnish–Swedish winter navigation system (FSWNS). This article focuses on accident risks in winter navigation operations, beginning with a brief outline of the FSWNS. The study analyses a hazard identification model of winter navigation and reviews accident data extracted from four winter periods. These are adopted as a basis for visualizing the risks in winter navigation operations. The results reveal that experts consider ship independent navigation in ice conditions the most complex navigational operation, which is confirmed by accident data analysis showing that the operation constitutes the type of navigation with the highest number of accidents reported. The severity of the accidents during winter navigation is mainly categorized as less serious. Collision is the most typical accident in ice navigation and general cargo the type of vessel most frequently involved in these accidents. Consolidated ice, ice ridges and ice thickness between 15 and 40 cm represent the most common ice conditions in which accidents occur. Thus, the analysis presented in this article establishes the key elements for identifying the operation types which would benefit most from further safety engineering and safety or risk management development. 相似文献
902.
Milton C. Chew 《技术计量学》2013,55(4):919-920
The density of a symmetric statistic T = g(X 1, X 2, …, Xn ), for a random sample from a mixed population with density f(x) = pf 1(x) + pf 2), is a binomial mixture of the densities of the statist.ics Tk = g(Xk1 , Xk2 , Xkn ), k = 0, 1, … n. where Xki 's are independent with density f 1(x) if i ≤ k and density f 2(x) if i > k. It is shown how to find the distributions of some important symmetric statistics like sample mean, sample variance, and order statistics by using Tk 's. The results are applied to normal and exponential mixtures. 相似文献
903.
A Vasquez Y Valdez RH Gilman JJ McDonald TU Westblom D Berg H Mayta V Gutierrez 《Canadian Metallurgical Quarterly》1996,34(5):1232-1234
Resistance of Helicobacter pylori to metronidazole often causes failure of commonly used combination drug treatment regimens. We determined the MICs of metronidazole and clarithromycin against 18 H. pylori strains from Peru using tetrazolium egg yolk (TEY) agar. The MIC results obtained by agar dilution with petri dishes were compared with the results found through a miniwell format. The results of the two protocols for measuring drug susceptibility differed by no more than 1 dilution in all cases. On TEY agar, bright-red H. pylori colonies were easy to identify against a yellow background. Sixty-one percent (11 of 18) of the strains were resistant to metronidazole (MIC, > or = 4 micrograms/ml) and 50% (9 of 18) were resistant to clarithromycin (MIC, > or = 0.125 micrograms/ml), whereas none (0 of 5) of the strains tested were resistant to tetracycline (MIC, > or = 1 micrograms/ml). Thus, the prevalence of metronidazole and clarithromycin resistance in Peru is higher than that in developed regions of the world. The miniwell plate with TEY agar allows easy H. pylori colony identification, requires about one-third less of the costly medium necessary for petri dish assaying, conserves space, and yields MICs equivalent to those with agar dilution in petri dishes. 相似文献
904.
Culture, cross-role consistency, and adjustment: Testing trait and cultural psychology perspectives.
Church A. Timothy; Anderson-Harumi Cheryl A.; del Prado Alicia M.; Curtis Guy J.; Tanaka-Matsumi Junko; Valdez Medina José L.; Mastor Khairul A.; White Fiona A.; Miramontes Lilia A.; Katigbak Marcia S. 《Canadian Metallurgical Quarterly》2008,95(3):739
Trait and cultural psychology perspectives on cross-role consistency and its relation to adjustment were examined in 2 individualistic cultures, the United States (N = 231) and Australia (N = 195), and 4 collectivistic cultures, Mexico (N = 199), the Philippines (N = 195), Malaysia (N = 217), and Japan (N = 180). Cross-role consistency in trait ratings was evident in all cultures, supporting trait perspectives. Cultural comparisons of mean consistency provided support for cultural psychology perspectives as applied to East Asian cultures (i.e., Japan) but not collectivistic cultures more generally. Some but not all of the hypothesized predictors of consistency were supported across cultures. Cross-role consistency predicted aspects of adjustment in all cultures, but prediction was most reliable in the U.S. sample and weakest in the Japanese sample. Alternative constructs proposed by cultural psychologists-personality coherence, social appraisal, and relationship harmony-predicted adjustment in all cultures but were not, as hypothesized, better predictors of adjustment in collectivistic cultures than in individualistic cultures. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
905.
H. Khavarian P.M. Atkinson E.J. Milton J.B. Stewart 《International journal of remote sensing》2013,34(20):7376-7399
Surface reflectance obtained from remote-sensing data is the main input to almost all remote-sensing applications. The availability and special characteristics of Moderate Resolution Imaging Spectroradiometer (MODIS) products have led to their use worldwide. Validation of the MODIS reflectance product is then crucial to provid information on uncertainty in the reflectance data, and in other MODIS products and in the applied surface–atmosphere models. Compact Airborne Spectrographic Imager (CASI) and Système Pour l'Observation de la Terre (SPOT) data, collected during the Network for Calibration and Validation in Earth Observation (NCAVEO) 2006 Field Campaign, were applied to validate daily MODIS reflectance data over a site in the southern UK. The difference in the view geometry of at-nadir CASI and SPOT data and off-nadir MODIS data was dealt with using a semi-empirical bidirectional reflectance distribution function (BRDF) model. The validation results showed that for our particular study site, the absolute errors in the MODIS reflectance product were too large to allow the albedo data to be used directly in climate models. The errors were mainly related to the uncertainties in the MODIS atmospheric variables, the BRDF model, and undetected clouds and cloud shadows. More generally, the study highlights the extreme difficulty of achieving pixel-level validation of coarse spatial resolution satellite sensor data in an environment in which the atmosphere is constantly changing, and in which the landscape is characterized by high space–time heterogeneity. 相似文献
906.
Zhi-Hong Yang Kimball Nill Yuki Takechi-Haraya Martin P. Playford David Nguyen Zu-Xi Yu Milton Pryor Jingrong Tang Krishna Vamsi Rojulpote Nehal N. Mehta Han Wen Alan T. Remaley 《International journal of molecular sciences》2022,23(15)
Both monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) play important roles in lipid metabolism, and diets enriched with either of these two fatty acids are associated with decreased cardiovascular risk. Conventional soybean oil (CSO), a common food ingredient, predominantly contains linoleic acid (LA; C18:2), a n-6 PUFA. Recently, a modified soybean oil (MSO) enriched in oleic acid (C18:1), a n-9 MUFA, has been developed, because of its improved chemical stability to oxidation. However, the effect of the different dietary soybean oils on cardiovascular disease remains unknown. To test whether diets rich in CSO versus MSO would attenuate atherosclerosis development, LDL receptor knock-out (LDLR-KO) mice were fed a Western diet enriched in saturated fatty acids (control), or a Western diet supplemented with 5% (w/w) LA-rich CSO or high-oleic MSO for 12 weeks. Both soybean oils contained a similar amount of linolenic acid (C18:3 n-3). The CSO diet decreased plasma lipid levels and the cholesterol content of VLDL and LDL by approximately 18% (p < 0.05), likely from increased hepatic levels of PUFA, which favorably regulated genes involved in cholesterol metabolism. The MSO diet, but not the CSO diet, suppressed atherosclerotic plaque size compared to the Western control diet (Control Western diet: 6.5 ± 0.9%; CSO diet: 6.4 ± 0.7%; MSO diet: 4.0 ± 0.5%) (p < 0.05), independent of plasma lipid level changes. The MSO diet also decreased the ratio of n-6/n-3 PUFA in the liver (Control Western diet: 4.5 ± 0.2; CSO diet: 6.1 ± 0.2; MSO diet: 2.9 ± 0.2) (p < 0.05), which correlated with favorable hepatic gene expression changes in lipid metabolism and markers of systemic inflammation. In conclusion, supplementation of the Western diet with MSO, but not CSO, reduced atherosclerosis development in LDLR-KO mice independent of changes in plasma lipids. 相似文献
907.
María Belén Valdez Diana María Bernal Giménez Lucía Raquel Fernández Alejandro Daniel Musikant Gabriel Ferri Daniel Sáenz Gabriela Di Venosa Adriana Casas Esteban Avigliano Martín Miguel Edreira Jorge Alejandro Palermo 《ChemMedChem》2022,17(5):e202100784
We report the synthesis of 16 new compounds obtained from kokusaginine and flindersiamine, the main alkaloids isolated from the bark of Balfourodendron riedelianum. The activity of the compounds against axenic cultures of Trypanosoma cruzi epimastigtotes and trypomastigotes, as well as intracellular amastigotes, is described, together with their cytotoxic activity against three different human cell lines. The synthetic strategy for the preparation of the new compounds was based on the reactivity at the C4 position of the furoquinoline core towards nucleophiles. The new derivatives were synthesized by a Buchwald-Hartwig reaction, in most cases under green, solvent-free conditions. Compounds 1 c and 1 e displayed better in-vitro activity against trypomastigotes than benznidazole and nifurtimox (positive controls) with IC50<4 μM. In addition, both compounds were not cytotoxic against the three human cell lines K562 (erytroleukimia), LM2 (breast cancer), and HaCat (keratinocyte). Interestingly, when evaluated against intracellular amastigotes, compound 1 c was able to significantly reduce the number of this parasite form, compared to the negative control. 相似文献
908.
Daniel R. Lowry Joseph R. Boro Mia Blea-Kirby Nichole R. Valdez Sean R. Bishop 《Journal of the American Ceramic Society》2023,106(11):7078-7087
Phase formation and stability of five component compositionally complex rare earth zirconates (5RE2Zr2O7) were investigated by X-ray diffraction and electron microprobe analysis. Zirconates with different rare earth compositions (LaNdSmEuDy, LaNdSmEuYb, LaNdEuErYb, LaNdDyErYb, SmEuDyYHo, LaYHoErYb, and DyYHoErYb) were synthesized at 1700°C and 2000°C by the solid-state method to investigate the effect of A-site site disorder (δA) on phase stability. Increased site disorder results from mixed cation occupancy with localized crystallographic strain and bond disorder. Compositions LaNdSmEuDy (δA = 4.6) and LaNdSmEuYb (δA = 6.0) produced a single pyrochlore phase and compositions SmDyYHoErYb (δA = 2.8), LaYHoErYb (δA = 6.2), and DyYHoErYb (δA = 1.7) produced a single fluorite phase. High δA compositions LaNdEuErYb (δA = 6.9) and LaNdDyErYb (δA = 7.2) produced a pyrochlore and fluorite phase mixture at 1700°C. Single phase was obtained for the latter composition at 2000°C. Of the single phase compositions calcined at 1700°C, LaNdSmEuYb and LaYHoErYb (both with largest δA) showed decomposition to mixed fluorite and pyrochlore phases during lower temperature anneals, indicating entropic stabilization. Comparison with prior work shows a temperature dependence of the critical δA for phase stability, and compositions near it are expected to be entropy stabilized. 相似文献
909.
Adil Darvesh Manuel Sánchez-Chero José Antonio Sánchez-Chero Víctor Daniel Hijar Hernández Milton Doroteo Cayambe Guachilema Julissa Elizabeth Reyna-Gonzalez 《亚洲传热研究》2023,52(6):4293-4316
The aim of this study is to examine the impact of motile gyrotactic microorganisms on three-dimensional (3D) cylindrical geometry attached to a Cross-fluid flow mathematical model. The motion of the microorganisms is assumed to be governed by gyrotaxis, which is the tendency of the organisms to orient and swim perpendicular to fluid flow gradients. The study will incorporate the effects of the Cross fluid flow model with infinite shear rate viscosity, 3D cylinder geometry, and microorganism behavior on the resulting distribution and concentration of the organisms. For the inspection of the velocity profile of the Cross nanofluid, the inclined magnetic field is scrutinized. The temperature of Cross nanofluid and its concentration is also studied with several facts. Mass flux and heat flux values for motile microorganisms and nanoparticles are calculated through statistical graphs. Brownian motion parameter gives a lower concentration of nanoparticles, about 81.19% and 77.53% reduction is found in the concentration of motile microorganisms. These results will provide insights into the behavior of these microorganisms in natural and engineered environments, as well as their potential applications in fields such as biotechnology, environmental science, and medicine. 相似文献