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61.
Soldering experiments of quad flat package(QFP) devices were carried out by means of diode laser soldering system with Sn-Ag-Cu and Sn-Cu-Ni lead-free solders, and competitive experiments were also carried out not only with Sn-Pb eutectic solders but also with infrared reflow soldering method. The results indicate that under the conditions of laser continuous scanning mode as well as the fixed laser soldering time, an optimal power exists, while the optimal mechanical properties of QFP micro-joints are gained. Mechanical properties of QFP micro-joints soldered with laser soldering system are better than those of QFP micro-joints soldered with IR reflow soldering method. Fracture morphologies of QFP micro-joints soldered with laser soldering system exhibit the characteristic of tough fracture, and homogeneous and fine dimples appear under the optimal laser output power. 相似文献
62.
氧原子向稀土相YSn3晶格内部的扩散使YSn3产生体积膨胀,而周围钎料基体对体积膨胀的抑制作用使其内部产生巨大的压应力,此压应力为Sn晶须的生长提供了驱动力;与此同时,稀土相YSn3氧化过程中释放出的自由Sn原子为Sn晶须的生长提供了生长源.对空气中室温与150℃时效条件下稀土相YSn3表面Sn晶须的生长进行了研究.结果表明,室温时效条件下,稀土相YSn3表面Sn晶须的生长速度缓慢且分布不均;高温时效条件下,稀土相YSn3表面Sn晶须的生长速度较快且巨大的压应力使钎料基体发生了隆起现象. 相似文献
63.
在电子组装早期用得最多的焊料主要是锡和铅两种元素,尤其是质量百分比为w(Sn)63%和w(Pb)37%的共晶铅锡合金为多数电子产品所采用.大量使用的Sn/Pb合金焊料正是造成污染的重要来源之一.在制造和使用Sn/Pb焊料的过程中,由于熔化温度较高,有大量的铅蒸气逸出,将严重影响操作人员的身体健康.同时焊接互联的常见热疲劳失效与富铅相有关,期望在设计锡基无铅焊料中不含有铅相,从而改善力学性能,强化焊料.介绍了无铅焊料的基本要求、无铅焊料的研究现状、无铅焊料面临的问题:指出无铅焊料及焊接可靠性仍是工业界和学术界研究的热点问题. 相似文献
64.
The eutectic Sn-9Zn alloy was doped with Ag (0 wt.%-1 wt.%) to form Sn-9Zn-xAg lead-free solder alloys. The effect of the addition of Ag on the microstructure and solderability of this alloy was investigated
and intermetallic compounds (IMCs) formed at the solder/Cu interface were also examined in this study. The results show that,
due to the addition of Ag, the microstructure of the solder changes. When the quantity of Ag is lower than 0.3 wt.%, the needle-like
Zn-rich phase decreases gradually. However, when the quantity of Ag is 0.5 wt.%-1 wt.%, Ag-Zn intermetallic compounds appear
in the solder. In particular, adding 0.3 wt.% Ag improves the wetting behavior due to the better oxidation resistance of the
Sn-9Zn solder. The addition of an excessive amount of Ag will deteriorate the wetting property because the glutinosity and
fluidity of Sn-9Zn-(0.5, 1)Ag solder decrease. The results also indicate that the addition of Ag to the Sn-Zn solder leads
to the precipitation of ε-AgZn3 from the liquid solder on preformed interfacial intermetallics (Cu5Zn8). The peripheral AgZn3, nodular on the Cu5Zn8 IMCs layer, is likely to be generated by a peritectic reaction L + γ-Ag5Zn8 → ɛ-AgZn3 and the following crystallization of AgZn3. 相似文献
65.
稀土Ce加速Sn晶须生长的研究 总被引:1,自引:0,他引:1
稀土被认为是金属中的"维他命",在钎料中添加微量的稀土Ce可以显著地改善钎料合金的综合性能.然而,当钎料中添加过量的稀土时,将会发现Sn晶须的快速生长现象.结果表明,如果将Sn3.8Ag0.7Cu1.0Ce钎料内部的稀土相暴露于空气中,稀土相将发生氧化而产生体积膨胀,钎料基体对体积膨胀的抑制作用将使稀土相内部产生巨大的压应力从而加速Sn晶须的生长. 相似文献
66.
利用光学显微镜、扫描电子显微镜(SEM)和能谱分析仪(EDX)及Instron电液伺服疲劳拉伸试验机,对SnAgCu系无铅钎料合金的力学性能和钎焊性能进行了研究.结果表明,适量的稀土元素Ce的添加显著地延长了Sn3Ag2.8Cu钎焊接头在室温下的蠕变断裂寿命,Sn3Ag2.8Cu-0.1Ce钎焊接头的蠕变断裂寿命超过Sn3Ag2.8Cu钎料的9倍;同时,使Sn3Ag2.8Cu合金的延伸性能也得到了显著改善,伸长率达到15.7%;Sn3Ag2.8Cu-0.1Ce与铜基板的扩散层厚度比Sn37Pb厚,但是比Sn3Ag2.8Cu薄. 相似文献
67.
The present study details the microstructure evolution of the interfacial intermetallic compounds (IMCs) layer formed between
the Sn-xAg-0.5Cu (x = 1, 3, and 4 wt.%) solder balls and electroless Ni-P layer, and their bond strength variation during aging. The interfacial
IMCs layer in the as-reflowed specimens was only (Cu,Ni)6Sn5 for Sn-xAg-0.5Cu solders. The (Ni,Cu)3Sn4 IMCs layer formed when Sn-4Ag-0.5Cu and Sn-3Ag-0.5Cu solders were used as aging time increased. However, only (Cu,Ni)6Sn5 IMCs formed in Sn-1Ag-0.5Cu solders, when the aging time was extended beyond 1500 h. Two factors are expected to influence
bond strength and fracture modes. One of the factors is that the interfacial (Ni,Cu)3Sn4 IMCs formed at the interface and the fact that fracture occurs along the interface. The other factor is Ag3Sn IMCs coarsening in the solder matrix, and fracture reveals the ductility of the solder balls. The above analysis indicates
that during aging, the formation of interfacial (Ni,Cu)3Sn4 IMCs layers strongly influences the pull strength and the fracture behavior of a solder joint. This fact demonstrates that
interfacial layers are key to understanding the changes in bonding strength. Additionally, comparison of the bond strength
with various Sn-Ag-Cu lead-free solders for various Ag contents show that the Sn-1Ag-0.5Cu solder joint is not sensitive to
extended aging time. 相似文献
68.
This letter describes the successful fabrication of a 0.95Sn−0.05Au solder microbump on a compound semiconductor wafer by
reflowing of multi-layer metal film. Since the inherent interdiffusion in Au−Sn phases results in the alloying of multi-layer
films, the composition of micro-bump is well controlled by the thickness of constituent metal films. The micro-bumps melt
at about 220 C, which is close to the lowest eutectic temperature in a Au−Sn system. Solder bonding using 0.95Sn−0.05Au micro-bump
is a very useful technique for the flipchip bonding of compound semiconductor devices. 相似文献
69.
70.