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221.
球形磁铁在弯管内表面磁力研磨中的应用 总被引:7,自引:0,他引:7
空间弯管内表面微裂纹用传统的研磨方法难以去除.利用六自由度机械手结合磁力研磨加工装置实现空间弯管内表面研磨加工.为了提高磁力研磨弯管内表面的加工效率,根据研磨工艺数学模型分析得到提高研磨压力是提高研磨效率的有效手段.因此,提出在研磨介质中添加球形磁铁作为辅助抛光工具提高研磨介质对弯管内表面的压力.通过Ansoft Maxwell软件分析得到添加球形磁铁后加工区域的磁感应强度增大,即研磨压力变大.并对TB8合金弯管进行研磨试验,试验结果表明添加球形磁铁后研磨加工效率提高约40%;表面粗糙度降至0.09 μm左右,并通过电子显微镜观察到内表面上的微裂纹已去除.实验验证了球形磁铁辅助研磨弯管内表面的可行性,为提高磁力研磨加工效率提供了一种新方法. 相似文献
222.
223.
侧边抛磨区材料折射率对光纤光栅波长的影响 总被引:9,自引:2,他引:7
针对轮式光纤侧边抛磨法,研究了在侧边抛磨光纤光栅抛磨区覆盖不同折射率的材料时,侧边抛磨光纤光栅Bragg波长随外界折射率的改变而变化的特性.理论计算与实验结果都表明,侧边抛磨光纤光栅Bragg波长会随抛磨区覆盖材料折射率的增大向长波长方向偏移;侧边抛磨面离光栅区纤芯表面越近,覆盖材料折射率对波长偏移的影响越大.实验指出,当侧边抛磨区覆盖材料的折射率从1.389 7变到1.447 9时,Bragg波长将会发生1.402 nm的偏移.用轮式光纤侧边抛磨法制备的侧边抛磨光纤光栅可应用于光纤光栅的波长调谐或传感器. 相似文献
224.
Localized corrosion effects and modifications of acidic and alkaline slurries on copper chemical mechanical polishing 总被引:3,自引:0,他引:3
This study demonstrates the CMP performance can be enhanced by modifying the corrosion effects of acidic and alkaline slurries on copper. A corrosion test-cell with a polishing platform is connected with the potentiostat to investigate the corrosion behaviors of copper CMP in various alumina slurries. Experiments show that the slurry needs to be maintained in acidic pH<4.56 or alkaline pH>9.05 surroundings and thus better dispersion of alumina particles and less residual contaminant on copper surface can be obtained. The surface defects after copper CMP using acidic and alkaline slurries are described by pitting corrosion mechanisms, and these mechanisms can be regarded as a basis to modify their corrosion effects. Experimental results indicate that it is necessary to modify the dissolution of HNO3 and oxidization of NH4OH for copper CMP slurries. Consequently, the slurries of 5 wt.% HNO3 by adding 0.1 wt.% BTA or 5 wt.% KNO3 by adding 1 wt.% NH4OH achieve good CMP performance for copper with higher CMP efficiency factor (CMPEF), 1460 and 486, and lower surface roughness (Rq), 4.019 and 3.971 nm, respectively. It is found that AFM micrographs can support the effectiveness of corrosion modifications for copper CMP in various slurry chemistries. 相似文献
225.
加工平行平面锗窗片,采用双面研磨法修改平行度,用吸附方法粘结成盘,固着磨料抛光模粗抛,沥青抛光模精抛,解决了批量生产中等精度(平行度等于1!@)锗窗片的加工工艺。该工艺也适用于其他晶体材料的平面加工。 相似文献
226.
When products are sold under warranty, the manufacturer incursadditional costs for warranty servicing. Preventive maintenanceactions can be used to reduce this cost and these are worthwhileonly if the extra cost incurred is less than the reduction achieved.In this paper we propose a new preventive maintenance policywhere the parameters are selected optimally to minimize thetotal warranty servicing cost. 相似文献
227.
Automatic recognition and evaluation of micro-contaminant particles on ultra-smooth optical substrates using image analysis method 总被引:3,自引:0,他引:3
X. K. Shi M. Hua E. H. M. Cheung M. Li W. Z. Yuan 《Optics and Lasers in Engineering》2004,41(6):901-917
Micro-contaminant particles on surface of optical substrate have unfavorable influence on light characteristics and instability of optical devices. Proper recognition and evaluation of micro-contaminant particles on post-cleaning substrate are important in fabricating high-performance optical substrates. Based on image analysis and difference of gray scale threshold in image zones, this paper presents a technique for automatically recognizing micro-contamination, and the relevant software developed for on-line evaluation of the level of cleanliness on ultra-smooth optical substrate. Using the self-developed software incorporating high-resolution microscope, optical yttrium iron garnet (YIG) and K8 substrate surfaces of post-chemical mechanical polishing (CMP) were investigated. Results from analyzing the YIG and K8 optical substrates before-and-after laser cleaning illustrated the success of the developed automatic recognition and on-line evaluation system in identifying the micro-contaminant particles on the ultra-smooth substrate surface. 相似文献
228.
Generation and removal of pits during chemical mechanical polishing process for MgO single crystal substrate 总被引:1,自引:0,他引:1
Magnesium oxide (MgO) single crystal is an important substrate for high temperature superconductor, ferroelectric and photoelectric applications. The function and reliability of these devices are directly affected by the quality of polished MgO surface because any defect on the substrate, such as pit or scratch, may be propagated onto device level. In this paper, chemical mechanical polishing (CMP) experiments were conducted on MgO (1 0 0) substrate using slurry mainly comprised of 1-hydroxy ethylidene-11-diphosphonic acid (HEDP) and silica or ceria particles. Through monitoring the variations of the pits topography on substrate surface, generation and removal mechanism of the pits were investigated. The experimental results indicate that the pits were first generated by an indentation or scratch caused by particles in the slurry. If the rate of chemical etching in the defect area is higher than the material removal rate, the pits will grow. If chemical reaction in the defect area is slower than the material removal rate, the pits will become smaller and eventually disappear. Consequently, these findings may provide insight into strategies for minimizing pits during CMP process. 相似文献
229.
根据大口径非球面光学元件的实际加工需要,设计并制造可控气囊抛光系统,并对机构进行运动学仿真,仿真结果表明,气囊自转轴的运动空间可以满足大口径非球面光学元件的连续进动加工要求。为了证明所设计系统的可加工性,以直径320 mm的圆形平面光学元件进行加工实验。经过该气囊抛光工具24 h的抛光后,工件达到较好的面型精度,光学元件的表面粗糙度由0.272减小到0.068(=632.8 nm), PV值从1.671降低到0.905。对光学元件的实际加工实验结果表明:可控气囊抛光系统在加工过程中结构稳定性好,符合设计要求,可有效提高加工工件面型精度。 相似文献
230.