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111.
吴晓红 《武汉职业技术学院学报》2014,(3):82-84
采用波长为1.06μm的Nd:YAG激光器对胃镜活检钳进行焊接,通过调节激光的电流、脉冲宽度、离焦量等工艺参数对其进行精密焊接试验。研究结果表明,影响焊接效果的因素中,脉冲宽度决定了焊缝的凸起程度。通过采用较小激光能量条件下重复焊接两次或者三次这一独特工艺方法来克服激光能量稳定性、工件公差等缺陷,达到很好的焊接效果。 相似文献
112.
利用JGK6180X60-10型轧辊激光毛化/强化机组开展森吉米尔轧机工作辊激光毛化试验,然后直接在工作辊上观察毛化区域表面形貌、测量毛化区域表面粗糙度,并做相应分析;试验结果表明,该机组能够实现森吉米尔轧机工作辊表面的无序毛化加工。在本试验条件下,当激光光斑轴向点间距小于等于0.03mm时,毛化效果开始呈现出无序状态。 相似文献
113.
采用IPG5000高功率光纤激光焊接研究了激光工艺参数对焊缝表面形貌的影响,结果表明:当焊接速度较高时,焊缝形貌较差;保持激光功率不变,降低焊接速度,焊缝形貌可以得到一定的改善;降低激光功率的同时降低焊接速度可获得好的焊缝形貌。 相似文献
114.
《Journal of Cultural Heritage》2014,15(5):479-489
This study proposes a procedure for digitally classifying and cataloging moulds which belong to the historic collection of the Ginori porcelain factory in Doccia (Sesto Fiorentino, Italy). In addition to a vast number of antique plaster moulds, this collection includes artistic porcelain artifacts obtained from casting porcelain using the moulds and models made of various materials. The proposed methodology includes two workflows: the first starts with photographic and casting processes conducted recently on various groups of moulds and involves historical surveys for investigating the relationships between the various sets of moulds, the models from which they were derived and the porcelain objects derived from them. The second workflow was applied when no information was available for a set of moulds, and involved 3D scanning of the moulds, with virtual reconstruction of the corresponding model followed by a final art historical survey like that used in the first procedure. 3D scanning techniques and successive model reconstruction can also be applied for obtaining a virtual model in the first process, when the physical model was lost, damaged or never existed. The variety and extent of the Ginori collection suggested the use of a customized Data-Base (DB) and a set of functions designed to manage and extract information, data and archived images. This filing system, called DocciaDigitalArchive (DDA), also makes it possible to specify the relationships between the different typology samples (prototype models, moulds derived from them, handmade porcelain objects produced from these moulds), which are associated when the same subject is portrayed. The DB structure conceived also provides the possibility of incorporating pictures and data of known archetypes. This additional information makes it possible to place each subject in its historical and artistic context. For each sample filed in the DDA system, documentary cards, which summarize data, images, reports and links to other entities or samples connected to the subject consulted, can be viewed on a suitable interface. 相似文献
115.
《Journal of Cultural Heritage》2014,15(3):258-265
Lasers have served as cleaning tools for historical objects and artworks for about 40 years. In many cases, superior results of laser cleaning were achieved with respect to traditional methods. In this technique, contaminations on the surface of the object are ablated by laser irradiation. In order to apply laser cleaning method to fragile materials such as paper made of cellulose or parchment, heat deposition to the bulk should be minimal, to prevent damage. In this work, it is demonstrated that laser pulses with femtosecond (fs) duration can exhibit non-thermal ablation of contaminants on paper samples. In particular, laser cleaning studies are concentrated on paper samples with sizing. Fs laser cleaning is performed on artificially soiled and aged samples, as well as on historical ones. The laser used in the experiments has pulse duration of 550 fs and 1030 nm center wavelength. The fluence of the laser is varied and the post-cleaning statuses of samples are investigated. The analyses are color changes, fiber integrity, chemical composition changes and mechanical strengths. These results show that fs lasers can be very efficient in cleaning paper samples, yielding minimal discoloration and no damage to fibers distinguishable on microscopic examination. The presence of sizing also provides further protection against possible side effects. 相似文献
116.
以TI公司的超低功耗MCU LM3S811单片机为核心控制器,设计并制作了一个LED点光源自动跟踪系统.LM3S811计算出位置误差后,采用PI控制算法处理,以驱动减速电机跟踪点光源.经过实际场景测试,当点光源支架沿着圆周和直线缓慢平稳移动限定的角度和距离时,该系统均能使激光笔在左右和上下移动方向上快速、连续地实现LED点光源的跟踪. 相似文献
117.
118.
针对齿轮激光表面淬火背面回火现象,采用有限差分法分析研究了背面温度响应值,并给出了温度响应值与激光工艺参数、齿轮参数的关系线图。其研究结果对于不同参数的齿轮在选择合理激光工艺参数,以避免发生背面回火方面具有实际应用价值。 相似文献
119.
This paper introduces a technical method by which bone tissue bionic scaffolds are fabricated on a selective laser sintering machine. It also analyses determinative factors in fabricating porous structure using this method, and proposes a new technique to fabricate porous structure by rapid prototyping method. 相似文献
120.
半导体激光治疗慢性牙髓炎和慢性根尖周炎 总被引:4,自引:0,他引:4
为探讨利用半导体激光治疗慢性牙髓炎和慢性根尖周炎的新办法,使用半导体激光光源及单模光纤将激光引入根管,对128只牙根管进行照射,并与常规根管治疗术进行对照比较,结果表明,激光治疗慢性牙髓炎和慢性根尖周炎组治愈率分别为96.15%和94.74%,疗效优于对照组,经统计学检查有显著性差异。 相似文献