首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   99篇
  免费   0篇
电工技术   2篇
化学工业   4篇
金属工艺   1篇
轻工业   2篇
无线电   32篇
一般工业技术   13篇
冶金工业   41篇
原子能技术   1篇
自动化技术   3篇
  2020年   1篇
  2019年   1篇
  2016年   3篇
  2015年   1篇
  2013年   2篇
  2012年   1篇
  2009年   2篇
  2007年   2篇
  2006年   3篇
  2005年   4篇
  2004年   3篇
  2003年   1篇
  2002年   3篇
  2001年   4篇
  2000年   4篇
  1999年   1篇
  1998年   18篇
  1997年   10篇
  1996年   3篇
  1995年   1篇
  1994年   7篇
  1993年   5篇
  1992年   4篇
  1991年   2篇
  1990年   1篇
  1989年   3篇
  1986年   1篇
  1985年   2篇
  1981年   1篇
  1978年   1篇
  1977年   1篇
  1975年   2篇
  1972年   1篇
排序方式: 共有99条查询结果,搜索用时 15 毫秒
81.
The authors present a technique for fibre management on a circuit board, which utilises newly-developed, flexible optical fibre circuits and multifibre physical contact connectors. The technique achieves compact fibre wiring and easy fibre connection for hundreds of fibres on a circuit board. The authors have fabricated a compact 8×16 delivery and coupling switch board using the technique  相似文献   
82.
Axonal transport plays a crucial role in neuronal morphogenesis, survival and function. Despite its importance, however, the molecular mechanisms of axonal transport remain mostly unknown because a simple and quantitative assay system for monitoring this cellular process has been lacking. In order to better characterize the mechanisms involved in axonal transport, we formulate a novel computer-assisted monitoring system of axonal transport. Potential uses of this system and implications for future studies will be discussed.  相似文献   
83.
Cyclooxygenase (COX)-2 expression was immunohistochemically examined in 59 human lung cancers as well as in normal and premalignant lung specimens. In contrast to scattered weak reactivity seen in normal peripheral airway epithelial cells, markedly up-regulated COX-2 expression was detected in about one-third of atypical adenomatous hyperplasias and carcinoma in situ specimens, and a significant increase in COX-2 expression was observed in 70% of invasive adenocarcinoma cases. Interestingly, the proportion of adenocarcinoma cells with marked COX-2 expression was much greater in lymph node metastases than in the corresponding primary tumors. In contrast, small cell carcinomas showed virtually negligible expression, and squamous cell carcinomas showed infrequent and low expression. These findings suggest that an increase in COX-2 expression may be associated with the development of adenocarcinomas and possibly with acquisition of an invasive and metastatic phenotype.  相似文献   
84.
There have been only a few investigational reports of sleep apnea syndrome (SAS) in patients with rheumatoid arthritis (RA), although it may not be a rare condition and may be life-threatening occasionally. The factor precipitating SAS in such patients is thought to be destruction of the temporomandibular joints (TMJs) from RA processes. To assess the relationship of the degree of destruction of the TMJs to the frequency of apnea, we examined them in 10 RA patients who complained of snoring. Those patients were classified as classical RA according to the criteria of American Rheumatism Association. They consisted of 3 males and 7 females with a mean age of 57.8 + 11.0 years and a mean disease duration of 15.9 +/- 9.4 years. In order to numerically evaluate the degree of destruction of the mandibular rami, we quoted a method from the literature (Redlund-Johnell I, Scand J Rheumatol 16:355, 1987) and measured the vertical distance (= ramal height) from the mandibular angle to the palato-occipital line on the lateral view film of the cervical spine in each patient. The mean values of ramal height (RH) of the normal material (we studied in Japanese) are 46.0 mm in males and 38.3 mm in females. There were 8 cases of SAS out of the 10 RA patients studied. Their mean total apneic episode (TAE) was 289.9 mm with a range of 0-611. The mean ratio (%) of RH to mean value of the normal material (%RH) was 68.8 +/- 22.2% for all. There was a significant statistic correlation between TAE and %RH (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
85.
A 58 year-old woman underwent radical nephrectomy, thrombectomy and ileo-cecal resection for renal tumor with thrombus involving the inferior vena cava and ascending colon cancer. In a patient having tumor thrombus extending to the vena cava, recognition of the position of the thrombus is important for surgical and anesthetic management in pre- and intra-operative periods. Transesophageal echocardiography (TEE) enabled us to visualize the real-time movement and deformity of thrombus by surgical manipulation and compression during operation. TEE seemed also very useful not only in understanding the hemodynamics during operation but also in detecting the residual tumor and the blood flow in liver and the inferior vena cava after operation.  相似文献   
86.
This paper reports on new fully-self-aligned gate technology for 0.2-μm, high-aspect-ratio, Y-shaped-gate heterojunction-FET's (HJFET's) with about half the external gate-fringing capacitance (Cfrext) of conventional Y-shaped gate HJFET's. The 0.2-μm Y-shaped gate openings are realized by anisotropic dry-etching with stepper lithography and SiO2 sidewall techniques instead of electron beam lithography. By introducing WSi-collimated sputtering and electroless gold-plating techniques for the first time, we have developed a high-aspect-ratio, voidless and refractory Y-shaped gate-electrode without the need for mask alignments. A fabricated 0.2-μm gate n-Al0.2Ga0.8As/In0.2Ga0.8As HJFET shows very small current saturation voltage of 0.25 V, marked gm max of 631 mS/mm with 6-V gate-reverse breakdown voltage, and excellent threshold voltage uniformity of 9 mV. Also, the improved rf-performance such as fT=71 GHz and fmax=120 GHz is realized even with the passivation for the high-aspect-ratio gate-structure with reduced Cfrext. The developed technology based upon a fully-self-aligned and an all-dry-etching process provides higher performance and uniformity, thus it is very promising for high-speed and low-power-consumption digital and/or analog IC's/LSI's  相似文献   
87.
The purpose of this work is to provide a simple, rational basis for combining bridge loads in the extreme event limit state. Classic methods are used to evaluate the probabilities of traffic, seismic, and storm-related bridge loads occurring simultaneously and in various intensities. The loads are modeled using a Poisson distribution, which circumvents problems encountered when using normal- or log-normal distributions. The hazard level is evaluated directly using a negative exponential function in the time domain. An acceptable hazard level for combined events is subjectively based on that deemed acceptable for the strength limit state and extreme events occurring individually, as well as fiscal prudence. It is shown that (1) application of seismic loads to a structure already subjected to the combined effects of degradation, local pier scour, and contraction of the waterway is not justifiable; (2) live loads reduced from the anticipated 75-year maximum to a 2-week maximum are appropriate when designing a bridge in its 100-year “scoured-out” storm configuration; and (3) vehicular live loads are likely to be on a bridge during a seismic event, but other issues need to be considered.  相似文献   
88.
89.
In anterior resection with anastomosis using the double-staple technique for low-lying rectal cancer in male patients, the approach to the anal canal with a stapling instrument via the abdominal area is limited by the narrow pelvis. The stapling and transection of the anal canal via the posterior transsacral approach prior to performing an anterior resection thus enables the lower rectum and anal canal to be visualized, so that the anal canal can be accurately stapled and transected even in male patients with a narrow pelvis.  相似文献   
90.
Clinical and radiological features of syringomyelia in 15 patients with spinal dysraphism are reported. There were 8 patients with occult spinal dysraphism (lumbosacral lipoma) and 7 with spina bifida aperta (meningomyelocele). Syringomyelia with spinal dysraphism can be radiologically divided into two types according to the dysraphic state. The syrinx in the patients with occult spinal dysraphism occurred immediately rostral to the lipoma and was localized to the lower thoracic to lumbar levels, while in the meningomyelocele patients the syrinx extended from the cervical to the thoracic level. Large syrinx formation was recognized in 1 of the 7 occult spinal dysraphism cases and 3 of the 8 meningomyelocele cases. For syringomyelia with occult spinal dysraphism, 4 patients underwent syringo-subarachnoid shunting (S-S shunt, 2 cases) or syringostomy (2 cases) during an untethering operation. In the case of meningomyelocele, S-S shunts were placed in 2 patients. Collapse of the syrinx was achieved in all 6 patients who underwent S-S shunting or syringostomy. Decreased size of the syrinx was also noted in 3 occult spinal dysraphism patients who underwent untethering operations alone. In conclusion, a large syrinx in the case of spinal dysraphism should be surgically treated. S-S shunting is effective in both types of syringomyelia. Foramen magnum decompression may be an alternative method of surgical treatment for syringomyelia in patients with meningomyelocele.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号