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排序方式: 共有1723条查询结果,搜索用时 15 毫秒
31.
Jixi Zhang Sergiy Kalnaus Majid Behrooz Yanyao Jiang 《Metallurgical and Materials Transactions A》2011,42(2):448-460
An experimental study of stress corrosion cracking (SCC) was conducted on 7075-T651 aluminum alloy in a chromate-inhibited, acidic 3.5 pct sodium chloride aqueous solution using compact tension specimens with a thickness of 3.8 mm under permanent immersion conditions. The effects of loading magnitude, overload, underload, and two-step high-low sequence loading on incubation time and crack growth behavior were investigated. The results show that the SCC process consists of three stages: incubation, transient crack growth, and stable crack growth. The incubation time is highly dependent on the load level. Tensile overload or compressive underload applied prior to SCC significantly altered the initiation time of corrosion cracking. Transition from a high to a low loading magnitude resulted in a second incubation but much shorter or disappearing transient stage. The stable crack growth rate is independent of stress intensity factor in the range of 10 to 22 MPa ?{textm} . sqrt {text{m}} . 相似文献
32.
R. Shariatzadeh M. Ghoranneviss M. Emami A. Anvari G. Van Oost 《Journal of Fusion Energy》2009,28(3):296-299
For the edge plasma parameters measurement, a movable Langmuir probe is fabricated and installed on the IR-T1 tokamak. The
set-up consists of two sets of single Langmuir probes with tungsten tip movable in the radial direction. Edge plasma parameters
including electron temperature, Ion density, floating potential and the corresponding radial changes are measured. Using two-point
correlation technique clearly reveal that in the SOL region the poloidal propagation of floating potential fluctuation is
in the direction of ion diamagnetic drift and in the edge it propagates in the electron diamagnetic drift direction. 相似文献
33.
Recently, the hole transport layer-free planar perovskite solar cells(HTL-free PSCs) have attracted intense attention. However, the poor absorption of light in the wavelengths longer than 800 nm is an important challenge in all configurations of PSCs. In this study, the HTL-free PSC with a gold rectangular grating at back contact is proposed. In order to improve the performance of the solar cell, effects of grating dimensions and periodicity on the absorption of the active layer are numerically ... 相似文献
34.
This paper reports on the synthesis of rice-like NiSe2 nanoparticles via a simple hydrothermal method by employing [bis(2-hydoxyacetophenato)nickle(II)], [Ni(HAP)2], as a novel nickel precursor. Effect of nickel source on morphology and size of nanostructures was also investigated. Moreover, the as-synthesized NiSe2 nanostructures were utilized as the photocatalyst for the degradation of methylene blue (MB) and as the counter electrode in dye-sensitized solar cells. The results showed that structures size and morphology have salient effect on solar cells and using rice-like NiSe2 nanoparticles leads to an increase in DSSCs efficiency compared to agglomerated sphere-like particles from 6.04 to 8.99?% (~49?% improvement). 相似文献
35.
Ahmad Rahimirad M. Emami M. Ghoranneviss A. Salar Elahi 《Journal of Fusion Energy》2009,28(4):420-426
We have expressed two different methods to determine the plasma positions in the IR-T1 tokamak. An array of magnetic probes
are placed polidally outside the chamber surface and their signals are plugged in the displacement equation and horizontal
displacement of plasma column is obtained. The results of this measurement are compared with the experimental data obtained
from sensors of multipole moment. It was detected a fluctuation in plasma displacement obtained with discrete magnetic coils,
so the method of multiple moments is better than the discrete magnetic coils for the determination plasma displacement that
used for feed back control. 相似文献
36.
Aliakbar Jafarzadeh Tahmineh Ahmadi Majid Taghian Dehaghani Kamran Mohemi 《Russian Journal of Non-Ferrous Metals》2018,59(4):458-464
In this study, a nano-composite composed of gelatin as the matrix and Si-Mg-FA nano-particles as an additive was deposited on the AZ31 Mg alloy via dip coating method. In addition, a coating composed of MgO, MgSiO3 and Mg2SiO4 phases was applied on the AZ31 Mg alloy by anodizing process. It was found that the Nano-composite coating with a uniform distribution of nano-particles within the gelatin matrix with the thickness of about 9 µm was dense, crack-free and uniform whereas the surface of anodized layer was relatively coarse due to the presence of flaws and micro-cracks. The surface morphology, EDS analysis and FTIR results revealed the ability of nano-composite coated specimen to form the bone-like apatite. Due to the presence of aforementioned phases and special surface features, the anodized specimen possessed higher and lower corrosion resistance than uncoated and nano-composite coated specimens, respectively. The passive coating resistances (RCT) of nano-composite, anodized specimen and uncoated samples were 2164, 1449 and 1024 Ω cm2, respectively. 相似文献
37.
Mahinzare Mohammad Barooti Mohammad Mostafa Ghadiri Majid 《Microsystem Technologies》2018,24(3):1695-1711
Microsystem Technologies - This article presented a numerical method for discovering the free vibration of a spinning bi-dimensional functionally graded materials (FGM) micro circular plate exposed... 相似文献
38.
Mohammadi Kianoosh Mahinzare Mohammad Ghorbani Khashayar Ghadiri Majid 《Microsystem Technologies》2018,24(2):1133-1146
Microsystem Technologies - In this article, a cylindrical functionally graded shell model is developed in the framework of nonlocal strain gradient theory for the first time. For this purpose, the... 相似文献
39.
This paper deals with the design and implementation of a relational database of macroscopic cross-sections as well as validation and its usage as a component in steady-state and transient analysis. These types of analysis are definitely designated as data-driven processes in which their behavior is changed based on data. The data in this manner can be the variation of fuel composition density as well as the fuel temperature during the reactor operation or in some accidents. In order to gain the accurate results in transient analysis, applying these variations is inevitable. Therefore, for each changing in fuel behavior, the new set of macroscopic cross-sections must be reproduced by performing the lattice calculations at run-time. During recent years some approaches have been done in both academic and commercial areas to take advantage of already calculated cross-sections instead of recalculate them by lattice codes during the analysis. Using this approach leverages the computation performance by reducing the floating point operations which can decrease the CPU load as well as the calculation time. Although this approach delivers a good performance in terms of time and computation, when a large number of fuel or reactor core circumstances are subjected to be analyzed the accuracy is became an important point. In this situation the cross-sections for all expected conditions must be already calculated. This cause the large number of cross-section data which must be stored and managed somehow. The system applied in this study to store and manage these cross-section data sets is a relational database management system (RDBMS) which is based on Microsoft SQL Server 2008 Management System. The node wise macroscopic cross-sections for each nominal and off-nominal of a typical medium sized PWR reactor core conditions which are calculated by WIMS-D5 and CITATION codes are tabulated in this system and can be retrieved by structured query language extremely rapid on demand. 相似文献
40.
Multidimensional Systems and Signal Processing - Extraction of fetal electrocardiogram (FECG) from the abdominal region of the mother’s skin is challenge task due to the high overlapping of... 相似文献