全文获取类型
收费全文 | 2264篇 |
免费 | 116篇 |
国内免费 | 15篇 |
专业分类
电工技术 | 52篇 |
综合类 | 7篇 |
化学工业 | 502篇 |
金属工艺 | 51篇 |
机械仪表 | 76篇 |
建筑科学 | 86篇 |
矿业工程 | 6篇 |
能源动力 | 188篇 |
轻工业 | 224篇 |
水利工程 | 18篇 |
石油天然气 | 23篇 |
无线电 | 261篇 |
一般工业技术 | 395篇 |
冶金工业 | 132篇 |
原子能技术 | 34篇 |
自动化技术 | 340篇 |
出版年
2024年 | 10篇 |
2023年 | 49篇 |
2022年 | 90篇 |
2021年 | 119篇 |
2020年 | 97篇 |
2019年 | 96篇 |
2018年 | 124篇 |
2017年 | 122篇 |
2016年 | 111篇 |
2015年 | 68篇 |
2014年 | 115篇 |
2013年 | 213篇 |
2012年 | 142篇 |
2011年 | 165篇 |
2010年 | 120篇 |
2009年 | 129篇 |
2008年 | 102篇 |
2007年 | 80篇 |
2006年 | 48篇 |
2005年 | 32篇 |
2004年 | 34篇 |
2003年 | 30篇 |
2002年 | 24篇 |
2001年 | 27篇 |
2000年 | 18篇 |
1999年 | 20篇 |
1998年 | 30篇 |
1997年 | 28篇 |
1996年 | 25篇 |
1995年 | 20篇 |
1994年 | 20篇 |
1993年 | 4篇 |
1992年 | 10篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 9篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1970年 | 1篇 |
排序方式: 共有2395条查询结果,搜索用时 15 毫秒
1.
Murat Ozdemir & Hasan Sadikoglu 《International Journal of Food Science & Technology》1998,33(5):439-444
The effects of addition of κ-carrageenan to solutions containing 40% (w/w) sugar substitute on the rheological properties of these systems were investigated at 25 °C using a rotational viscometer at rotational speeds of 6, 12, 30, and 60 rev min−1 . The flow behaviour of the solutions was adequately described by the power law model with or without yield stress. The consistency index ( K ) and the flow behaviour index ( n ) were determined from shear stress vs. shear rate data. The flow parameters of the solutions depended on the carrageenan concentration. The apparent viscosities of the systems decreased with increasing shear rate, indicating pseudoplastic behaviour. The final carrageenan concentration was found to be an effective factor controlling the degree of sliminess of the model food systems studied. 相似文献
2.
The interaction of different metal oxides such as Co3O4, NiO, Al2O3, Cr2O3, Fe2O3 and SiO2 with Na2SO4 at a temperature of 1100 and 1200 K in flowing oxygen has been studied. The thermogravimetric studies for each system were
carried out as a function of Na2SO4 in the mixture. The presence of different constituents in the reaction products were identified by X-ray diffraction analysis
and the morphologies of the reaction products were characterized using metallography and scanning electron microscopy (SEM).
The formation of products was also investigated by thermodynamic computation of free energies of the reactions and the study
of relevant equilibrium phase diagrams. The soluble species in the aqueous solutions of the reaction products were determined
quantitatively using atomic absorption spectrophotometry.
The high temperature interaction products usually contain a 3-phase structure namely, Na2O·M2O
x
, M2O
x
and metal sulphide and/or metal sulphate. The formation of Na2O·M2O
x
depends upon the solid state solubility of metal oxide in the molten salt at high temperatures. Under limited solubility
conditions Na2O·M2O
x
is invariably formed, but as soon as this condition is relaxed the oxide. M2O
x
, precipitates and forms a separate phase. 相似文献
3.
Demir H.V. Jun-Fei Zheng Sabnis V.A. Fidaner O. Hanberg J. Harris J.S. Jr. Miller D.A.B. 《Semiconductor Manufacturing, IEEE Transactions on》2005,18(1):182-189
This work reports an easy planarization and passivation approach for the integration of III-V semiconductor devices. Vertically etched III-V semiconductor devices typically require sidewall passivation to suppress leakage currents and planarization of the passivation material for metal interconnection and device integration. It is, however, challenging to planarize all devices at once. This technique offers wafer-scale passivation and planarization that is automatically leveled to the device top in the 1-3-/spl mu/m vicinity surrounding each device. In this method, a dielectric hard mask is used to define the device area. An undercut structure is intentionally created below the hard mask, which is retained during the subsequent polymer spinning and anisotropic polymer etch back. The spin-on polymer that fills in the undercut seals the sidewalls for all the devices across the wafer. After the polymer etch back, the dielectric mask is removed leaving the polymer surrounding each device level with its device top to atomic scale flatness. This integration method is robust and is insensitive to spin-on polymer thickness, polymer etch nonuniformity, and device height difference. It prevents the polymer under the hard mask from etch-induced damage and creates a polymer-free device surface for metallization upon removal of the dielectric mask. We applied this integration technique in fabricating an InP-based photonic switch that consists of a mesa photodiode and a quantum-well waveguide modulator using benzocyclobutene (BCB) polymer. We demonstrated functional integrated photonic switches with high process yield of >90%, high breakdown voltage of >25 V, and low ohmic contact resistance of /spl sim/10 /spl Omega/. To the best of our knowledge, such an integration of a surface-normal photodiode and a lumped electroabsorption modulator with the use of BCB is the first to be implemented on a single substrate. 相似文献
4.
Steady laminar binary mixed convection flow along a vertical circular cone under the combined buoyancy effects of thermal and species diffusion is studied analytically. The analysis is confined to mass diffusion processes with low concentration levels. In the analysis the surface of the cone is assumed to be at a uniform temperature and uniform concentration. Numerical results for the local Sherwood number, local Nusselt number and local friction factor are presented. Representative temperature, concentration and velocity profiles are also shown. The analysis covers the diffusion of common gases and vapours into air. Considerations are given to the situations where the buoyancy forces assist and oppose the forced convection flow for various possible combinations of the thermal and species diffusion processes. 相似文献
5.
Hasan Abbasi Nozari Hamed Dehghan Banadaki Mohammad Mokhtare Somayeh Hekmati Vahed 《浙江大学学报:C卷英文版》2012,(9):701
This study deals with the neuro-fuzzy (NF) modelling of a real industrial winding process in which the acquired NF model can be exploited to improve control performance and achieve a robust fault-tolerant system. A new simulator model is proposed for a winding process using non-linear identification based on a recurrent local linear neuro-fuzzy (RLLNF) network trained by local linear model tree (LOLIMOT), which is an incremental tree-based learning algorithm. The proposed NF models are compared with other known intelligent identifiers, namely multilayer perceptron (MLP) and radial basis function (RBF). Comparison of our proposed non-linear models and associated models obtained through the least square error (LSE) technique (the optimal modelling method for linear systems) confirms that the winding process is a non-linear system. Experimental results show the effectiveness of our proposed NF modelling approach. 相似文献
6.
Din Salah Ud Shao Junming Kumar Jay Mawuli Cobbinah Bernard Mahmud S. M. Hasan Zhang Wei Yang Qinli 《Knowledge and Information Systems》2021,63(9):2231-2276
Knowledge and Information Systems - Developing effective and efficient data stream classifiers is challenging for the machine learning community because of the dynamic nature of data streams. As a... 相似文献
7.
Liu Yongsheng Chen Wenyu Qu Hong Mahmud S. M. Hasan Miao Kebin 《Neural computing & applications》2021,33(10):4965-4978
Neural Computing and Applications - With only global image-level annotations, weakly supervised learning of deep convolutional neural networks has shown enough capacity in classification and... 相似文献
8.
Aziz Romila Anwar Muhammad Waqas Jamal Muhammad Hasan Bajwa Usama Ijaz 《Neural computing & applications》2021,33(21):14707-14721
Neural Computing and Applications - Detecting and correcting misspelled words in a written text are of great importance in many natural language processing applications. Errors can be broadly... 相似文献
9.
Teoman Dogru Ali Kirik Hasan Gurel Ali A. Rizvi Manfredi Rizzo Alper Sonmez 《International journal of molecular sciences》2021,22(12)
Nonalcoholic fatty liver disease (NAFLD) is strongly associated to the features of metabolic syndrome which can progress to cirrhosis, liver failure and hepatocellular carcinoma. However, the most common cause of mortality in people with NAFLD is not liver-related but stems from atherosclerotic cardiovascular disease (CVD). The prevalence of NAFLD is on the rise, mainly as a consequence of its close association with two major worldwide epidemics, obesity and type 2 diabetes (T2D). The exact pathogenesis of NAFLD and especially the mechanisms leading to disease progression and CVD have not been completely elucidated. Human fetuin-A (alpha-2-Heremans Schmid glycoprotein), a glycoprotein produced by the liver and abundantly secreted into the circulation appears to play a role in insulin resistance, metabolic syndrome and inflammation. This review discusses the links between NAFLD and CVD by specifically focusing on fetuin-A’s function in the pathogenesis of NAFLD and atherosclerotic CVD. 相似文献
10.
ABSTRACT The mixture of citrus fruits (orange, grapefruit, mandarin, and lemon) wastes was utilized to obtain high surface area activated carbon (AC) by H3PO4 activation. The production conditions were optimized and the optimum conditions were determined. The optimal-activated carbon (CFWAC) was characterized by various physicochemical techniques. CFWAC was also used as a sorbent for Pb (II) ions from water. Batch experiments were performed to explore the adsorption capacity and mechanism. The Langmuir isotherm and pseudo-second-order kinetic model showed good fitness to the experimental data. The maximum Pb (II) adsorption capacity of CFWAC was found to be 163.93 mg/g. 相似文献