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排序方式: 共有392条查询结果,搜索用时 15 毫秒
51.
焊膏工艺性要求及性能检测方法 总被引:9,自引:0,他引:9
焊膏是SMT工艺中不可缺少的钎焊材料,广泛应用于再流焊中;它是由一定的合金粉末和助焊剂均匀混合而成的膏状体。主要对SMT中焊膏的组成及焊膏性能检测方法进行了简要分析。 相似文献
52.
Recent experiments have shown failure in flip chip micro solder joints induced by electromigration. This paper proposes a three-dimensional computational model to simulate the evolution of micro and sub-micro scale solder joints due to electromigration induced diffusion. The evolving morphology of the solder joint related with multiple mechanisms causes a computational challenge. This is addressed by employing a diffuse interface model with multiple concentrations. To efficiently resolve complications, a semi-implicit Fourier spectral scheme and a biconjugate-gradient method are adopted. Results have demonstrated rich dynamics and solder breakage at the interface on the cathode side. Furthermore, the effect of the designed interface region on the reliability of solder joints has been investigated with the developed model. 相似文献
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54.
Effect of silver content on thermal fatigue life of Sn-xAg-0.5Cu flip-chip interconnects 总被引:5,自引:0,他引:5
Shinichi Terashima Yoshiharu Kariya Takuya Hosoi Masamoto Tanaka 《Journal of Electronic Materials》2003,32(12):1527-1533
The thermal fatigue properties of Sn-xAg-0.5Cu (x=1, 2, 3, and 4 in mass%) flip-chip interconnects were investigated to study
the effect of silver content on thermal fatigue endurance. The solder joints with lower silver context (x=1 and 2) had a greater
failure rate compared to those with higher silver content (x=3 and 4) in thermal fatigue testing. Cracks developed in the
solders near the solder/chip interface for all joints tested. This crack propagation may be mainly governed by the nature
of the solders themselves because the strain-concentrated area was similar for tested alloys independent of the silver content.
From the microstructural observation, the fracture was a mixed mode, transgranular and intergranular, independent of the silver
content. Higher silver content alloys (x=3 and 4) had finer Sn grains before thermal cycling according to the dispersion of
the Ag3Sn intermetallic compound, and even after the cycling, they suppressed microstructural coarsening, which degrades the fatigue
resistance. The fatigue endurance of the solder joints was strongly correlated to the silver content, and solder joints with
higher silver content had better fatigue resistance. 相似文献
55.
The microstructure of the flip-chip solder joints fabricated using stud bumps and Pb-free solder was characterized. The Au
or Cu stud bumps formed on Al pads on Si die were aligned to corresponding metal pads in the substrate, which was printed
with Sn-3.5Ag paste. Joints were fabricated by reflowing the solder paste. In the solder joints fabricated using Au stud bumps,
Au-Sn intermetallics spread over the whole joints, and the solder remained randomly island-shaped. The δ-AuSn, ε-AuSn2, and η-AuSn4 intermetallic compounds formed sequentially from the Au stud bump. The microstructure of the solder joints did not change
significantly even after multiple reflows. The AuSn4 was the main phase after reflow because of the fast dissolution of Au. In the solder joints fabricated using Cu stud bumps,
the scallop-type Cu6Sn5 intermetallic was formed only at the Cu interface, and the solder was the main phase. The difference in the microstructure
of the solder joints with Au and Cu stud bumps resulted from the dissolution-rate difference of Au and Cu into the solder. 相似文献
56.
圆片级封装是一种先进的电子封装技术,近年来,圆片级封装技术的发展速度很快,主要应用于系统级芯片、光电器件和MEMS等.凸点制作是圆片级封装工艺的关键工序,目前凸点制作工艺方法有多种,重点介绍常用的电镀法、植球法和蒸发沉积法凸点工艺,分别介绍这三种凸点制作技术的工艺流程、关键技术. 相似文献
57.
The underfill flow process is one of the important steps in Microsystems technology. One of the best known examples of such a process is with the flip-chip packaging technology which has great impact on the reliability of electronic devices. For optimization of the design and process parameters or real-time feedback control, it is necessary to have a dynamic model of the process that is computationally efficient yet reasonably accurate. The development of such a model involves identifying any factors that can be neglected with negligible loss of accuracy. In this paper, we present a study of flow transient behavior and flow resistance due to the presence of an array of solder bumps in the gap. We conclude (1) that the assumption of steady flow in the modeling of the flow behavior of fluids in the flip-chip packaging technology is reasonable, and (2) the solder bump resistance to the flow can not be neglected when the clearance between any two solder bumps is less than 60-70 μm. We subsequently present a new model, which extends the one proposed by Han and Wang in 1997 by considering the solder bump resistance to the flow. 相似文献
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