全文获取类型
收费全文 | 94篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 1篇 |
基础医学 | 31篇 |
口腔科学 | 12篇 |
临床医学 | 8篇 |
内科学 | 5篇 |
神经病学 | 3篇 |
外科学 | 7篇 |
综合类 | 5篇 |
预防医学 | 16篇 |
药学 | 7篇 |
肿瘤学 | 1篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 4篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2009年 | 5篇 |
2008年 | 9篇 |
2007年 | 5篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2002年 | 5篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1975年 | 2篇 |
排序方式: 共有100条查询结果,搜索用时 0 毫秒
1.
H. Tazawa Y. Hashimoto M. Takami Y. Yufu G. C. Whittow 《Medical & biological engineering & computing》1993,31(2):129-134
Using a flexible piezoelectric film, the authors developed a simple system to determine noninvasively the heart rate of chicken
embryos and hatchlings. The film was piezoelectric polyvinylidene fluoride (PVDF), which is sensitive enough to detect cardiogenic
ballistic movements of the egg (ballistocardiogram (BCG)) and precordial movements of the hatchling attributable to cardiac
contractions (apexcardiogram (ACG)). The BCG could be detected, during the second half of incubation, by placing the egg on
the PVDF film on a soft substrate. The detected signal was found to be a measure of movement velocity. The ACG could be measured
when the hatchling's chest wall made contact with the PVDF film installed in a box in which the hatchling was confined. The
heart rate was counted from the lag time of autocorrelation calculated for a certain time segment (e.g. 2s) of the BCG and
ACG recordings. 相似文献
2.
The movement of the larynx in five young men during the swallowing of a liquid was examined by simultaneously recording a video-movie, the trajectory of a piezoelectric sensor, and the surface electromyogram of the suprahyoid muscles (SH). The movies revealed swallowing was associated with four characteristic spatial points of laryngeal movement: (1) a slight movement in the superoposterior direction (1.9 ± 1.2 s; mean ± SD of the time elapsed after the command to swallow was issued); (2) the initiation of anterosuperior elevation (2.3 ± 1.3 s); (3) the turn at the highest position (3.2 ± 1.2 s); and (4) the return to the initial position (4.1 ± 1.4 s). The piezoelectric sensor and the SH electromyogram also detected characteristic temporal points that closely corresponded to the characteristic temporal points captured by the video. The advantages of using movies in swallowing research are discussed. 相似文献
3.
Intradural petrous bone drilling has become a widespread practice, providing extended exposure in the removal of cerebellopontine angle (CPA) or petroclival tumors. Adjacent neurovascular structures are at risk, however, when drilling is performed in this deep and narrow area. Hence, this study evaluates the use of Piezosurgery (PS) as a non-rotating tool for selective bone cutting in CPA surgery.A Piezosurgery® device was used in 36 patients who underwent microsurgery for extra-axial CPA or petroclival tumors in our Neurosurgical Department between 2013 and 2019. The clinical and radiological data were retrospectively analyzed. The use of PS was evaluated with respect to the intraoperative applicability and limitations as well as efficacy and safety of the procedure.Piezosurgical petrous bone cutting was successfully performed in the removal of meningiomas or extra-axial metastases arising from the dura of the petroclival region (21 patients) or petrous bone (15 patients). PS proved to be very helpful in the deep and narrow CPA region, considerably reducing the surgeon’s distress toward bone removal in close proximity to cranial nerves and vessels in comparison to common rotating drills. The use of PS was safe without injuries to neurovascular structures. Gross total resection was achieved in 67% of petroclival and 100% of petrous bone tumors.Piezosurgery proved to be an effective and safe method for selective petrous bone cutting in CPA surgery avoiding rotating power and associated risks. This technique can particularly be recommended for bone cutting in close vicinity to critical neurovascular structures. 相似文献
4.
Ra'ed Mohammed Ayoub Al-Delayme 《Saudi Dental Journal》2021,33(1):11-21
PurposeThe aim of this study was to evaluate the performance and to assess the postoperative sequel and quality of life after removal of impacted mandibular third molars using piezoelectric surgery compared with conventional rotatory osteotomy.Patients and methodsA single blinded, randomized, control clinical study was performed. Sixty-three patients (44 males, 19 females) who presented with bilaterally asymptomatic impacted mandibular third molars were included in this analysis. Each patient was treated, at two separate sessions approximately 4 weeks apart, with a conventional rotatory hand piece on one side of the mandible and a piezoelectric device on the contralateral side. Patients were followed up on postoperative days 1, 3, 5, 7, and 15 to rate the pain, swelling and trismus. Inferior alveolar nerve paresthesia was evaluated up to 12 months postoperatively.ResultsThe severity of the pain, trismus and swelling using the piezosurgery were significantly different from the rotary group. In both groups, pain was most intense and peaked during the first post-operative day, while swelling and trismus reached peak levels on the third postoperative day. The piezoelectric procedure resulted in a significantly longer procedural duration compared to the rotatory surgery (P < 0.001).ConclusionPiezoelectric surgery is considered a viable alternative technique compared to the conventional rotary systems and can improve a patient’s quality of life. Thus, piezoelectric surgery might be a preferred modality for patients undergoing complicated surgical extraction of impacted lower third molars. 相似文献
5.
Sara Amghar-Maach Alba Sánchez-Torres Octavi Camps-Font Cosme Gay-Escoda 《Journal of prosthodontic research》2018,62(4):391-396
Purpose
To answer the PICO question: “Among patients to whom an implant is placed, does the piezoelectric surgery (PS) compared to the conventional drilling (CS) achieve higher implant stability, increase surgical time or improve implant survival rate?”Study selection
Two independent authors screened the literature through MEDLINE, Cochrane Library and Scopus. Randomized or non-randomized controlled trials, prospective and retrospective cohort studies comparing implant stability and/or clinical outcomes with PS versus CS used for implant site preparation published in the last 10 years were included in the search.Results
Five of the 177 articles initially found were included in the meta-analysis. No statistically significant differences were found between PS and CS for implant stability quotient (ISQ) at baseline (SMD: 0.31; 95 %CI: ?0.59 to 1.20; p = 0.5). However, ISQ values were significantly higher at 2 months (SMD: 0.52; 95 %CI: 0.03–1.00; p = 0.04) and at 3 months (SMD: 0.74; 95 %CI: 0.17–1.32; p = 0.01) for CS. PS needed significantly more time than CS (SMD: 1.74; 95 %CI: 0.42–3.06; p = 0.01) in order to be performed. No differences for implant survival rates were found when comparing both techniques (RR: 0.52; 95 %CI: 0.09–2.88; p = 0.45).Conclusions
PS has not demonstrated superiority to conventional drilling for implant stability during the healing period. PS needs significantly longer surgery time than CS. Differences for implant survival rate were not found between the two techniques. 相似文献6.
Jochen Moll Christian Kexel Hamed Milanchian Mit Balvantray Bhavsar John Howard Barker 《Ultrasound in medicine & biology》2019,45(2):605-611
Approximately 6.3 million fractures occur each year in the United States alone. Accurately monitoring the progression of fracture healing is essential to be able to advise patients when it is safe to return to normal activity. The most common method used to confirm and monitor fracture healing is the acquisition of multiple radiographic images over the many months required for healing. This imaging method uses large expensive equipment and exposes patients to high levels of ionizing radiation. In the study described here, we tested another technology for monitoring fracture healing that could minimize the need for multiple radiographic images. We tested a piezoelectric transducer fixed to the surface of a bone that uses electromechanical impedance spectroscopy to measure simulated fractures and transmits the measurement data to an acoustic receiver located externally on the skin surface. 相似文献
7.
Asim Nisar Nitin Afzulpurkar Adisorn Tuantranont Banchong Mahaisavariya 《Cardiovascular Engineering》2008,8(4):203-218
In this paper, we present design of a transdermal drug delivery system for treatment of cardiovascular or hemodynamic disorders
such as hypertension. The system comprises of integrated control electronics and microelectromechanical system devices such
as micropump, micro blood pressure sensor and microneedle array. The objective is to overcome the limitations of oral therapy
such as variable absorption profile and the need for frequent dosing, by fabricating a safe, reliable and cost effective transdermal
drug delivery system to dispense various pharmacological agents through the skin for treatment of hemodynamic dysfunction
such as hypertension. Moreover, design optimization of a piezoelectrically actuated valveless micropump is presented for the
drug delivery system. Because of the complexity in analysis of piezoelectric micropump, which involves structural and fluid
field couplings in a complicated geometrical arrangement, finite element (FE) numerical simulation rather than an analytical
system has been used. The behavior of the piezoelectric actuator with biocompatible polydimethylsiloxane membrane is first
studied by conducting piezoelectric analysis. Then the performance of the valveless micropump is analyzed by building a three
dimensional electric-solid-fluid model of the micropump. The effect of geometrical dimensions on micropump characteristics
and efficiency of nozzle/diffuser elements of a valveless micropump is investigated in the transient analysis using multiple
code coupling method. The deformation results of the membrane using multifield code coupling analysis are in good agreement
with analytical as well as results of single code coupling analysis of a piezoelectric micropump. The analysis predicts that
to enhance the performance of the micropump, diffuser geometrical dimensions such as diffuser length, diffuser neck width
and diffuser angle need to be optimized. Micropump flow rate is not strongly affected at low excitation frequencies from 10
to 200 Hz. The excitation voltage is the more dominant factor that affects the flow rate of the micropump as compared with
the excitation frequency. However, at extremely high excitation frequencies beyond 8,000 Hz, the flow rate drops as the membrane
exhibits multiple bending peaks which is not desirable for fluid flow. Following the extensive numerical analysis, actual
fabrication and performance characterization of the micropump is presented. The performance of the micropump is characterized
in terms of piezoelectric actuator deflection and micropump flow rate at different operational parameters. The set of multifield
simulations and experimental measurement of deflection and flow rate at varying voltage and excitation frequency is a significant
advance in the study of the electric-solid-fluid coupled field effects as it allows transient, three dimensional piezoelectric
and fluid analysis of the micropump thereby facilitating a more realistic multifield analysis. The results of the present
study will also help to conduct relevant strength duration tests of integrated drug delivery device with micropump and microneedle
array in future. 相似文献
8.
适配子型压电石英晶体传感器检测人免疫球蛋白E的实验研究 总被引:1,自引:0,他引:1
目的研制适配子型压电子石英晶体传感器阵列与常用的免疫分析方法进行比较,以评价压电石英晶体传感器阵列检测灵敏度、特异性与临床检测的可行性。方法以AT切型、基频10MHz的镀金石英晶体作为换能器,将抗人免疫球蛋白E适配子固定在石英晶体电极表面,用2×5检测池阵列构建新型适配子型压电石英晶体传感器;分别进行标准品及人血清免疫球蛋白E的检测,研究了检测灵敏度、特异性等检测指标。结果该传感器可快速完成检测且无非特异性反应,在检测范围内传感器的响应特性良好,压电晶体频率偏移值与免疫球蛋白浓度呈良好的线性关系;将此免疫传感器用于人血清标本的测定,结果与化学发光法符合(r值=0.9924)。结论研制的传感器阵列具有灵敏度高、特异性好,检测通量高,无需标记,操作简便,能实时在线检测等优点,可用于临床实验诊断,具有较高的临床推广应用价值。 相似文献
9.
Three parameters α, DR and Dn(A), i.e. the efficiency, the dynamic range and the normalized axial resolution are used to evaluate the performance of ultrasound transducers for diagnostic imaging equipment. These parameters determine optimum conditions for use in the design of high frequency array transducers. A newly-developed piezoelectric ceramic material composed of (Pb,Sr)(Ti,Zr)O3 or Pb[(Mg, Nb), Ti,Zr]O3 which satisfies the above-mentioned conditions was used to fabricate a co-phase array ultrasound transducer. The transducer showed good electrical and acoustic performance in accordance with theoretical considerations. 相似文献
10.
目的研究运用压电石英晶体生物传感器对产气荚膜梭菌α毒素(CPα)进行检测的方法和反应条件。方法按照碱基配对的原则,设计特异的产气荚膜梭菌α毒素基因寡核苷酸探针并利用巯基自组装技术固定在石英晶体上,运用压电石英晶体生物传感器的“质量效应”对聚合酶链反应(PCR)扩增得到的产气荚膜梭菌α毒素靶基因进行杂交检测,并探讨不同pH值和不同离子强度的缓冲液对检测的影响。结果压电石英晶体生物传感器成功检测出产气荚膜梭菌α毒素;pH7.6的缓冲液和0.64mol/L的NaCl溶液最适合于检测。结论压电石英晶体生物传感器能够有效地检测产气荚膜梭菌α毒素,有望对临床上开展毒素诊断提供一种新的手段。 相似文献