全文获取类型
收费全文 | 1659篇 |
免费 | 178篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 17篇 |
综合类 | 2篇 |
化学工业 | 489篇 |
金属工艺 | 17篇 |
机械仪表 | 39篇 |
建筑科学 | 61篇 |
矿业工程 | 2篇 |
能源动力 | 72篇 |
轻工业 | 288篇 |
水利工程 | 26篇 |
石油天然气 | 6篇 |
无线电 | 115篇 |
一般工业技术 | 233篇 |
冶金工业 | 99篇 |
原子能技术 | 4篇 |
自动化技术 | 371篇 |
出版年
2024年 | 10篇 |
2023年 | 28篇 |
2022年 | 82篇 |
2021年 | 113篇 |
2020年 | 64篇 |
2019年 | 80篇 |
2018年 | 89篇 |
2017年 | 92篇 |
2016年 | 112篇 |
2015年 | 69篇 |
2014年 | 91篇 |
2013年 | 150篇 |
2012年 | 114篇 |
2011年 | 146篇 |
2010年 | 76篇 |
2009年 | 74篇 |
2008年 | 79篇 |
2007年 | 63篇 |
2006年 | 55篇 |
2005年 | 34篇 |
2004年 | 31篇 |
2003年 | 25篇 |
2002年 | 36篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 12篇 |
1998年 | 23篇 |
1997年 | 16篇 |
1996年 | 16篇 |
1995年 | 9篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有1841条查询结果,搜索用时 15 毫秒
1.
Martinez-Yelmo Isaias Alvarez-Horcajo Joaquin Briso-Montiano Miguel Lopez-Pajares Diego Rojas Elisa 《Telecommunication Systems》2019,72(4):555-565
Telecommunication Systems - The Software-Defined Networking (SDN) architecture decouples the control plane from the data plane, but it does not explicitly state where the control should be located.... 相似文献
2.
Precil Diego M. M. Neves Fernanda M. Freitas Christiane A. Kojima Beatriz L. Carmello Rodrigo Bazan Pasqual Barretti Luis C. Martin 《Hemodialysis international. International Symposium on Home Hemodialysis》2015,19(1):143-145
Antibiotics are potentially a cause of neurotoxicity in dialysis patients, the most common are the beta‐lactams as ceftazidime and cefepime, and few cases have been reported after piperacillin/tazobactam use. This report presents a case of a hypertensive and diabetic 67‐year‐old woman in regular hemodialysis, which previously had a stroke. She was hospitalized presenting pneumonia, which was initially treated with cefepime. Two days after treatment, she presented dysarthria, left hemiparesis, ataxia, and IX and X cranial nerves paresis. Computed tomography showed no acute lesions and cefepime neurotoxicity was hypothesized, and the antibiotic was replaced by piperacillin/tazobactam. The neurologic signs disappeared; however, 4 days after with piperacillin/tazobactam treatment, the neurological manifestations returned. A new computed tomography showed no new lesions, and the second antibiotic regimen withdrawn. After two hemodialysis sessions, the patient completely recovered from neurological manifestations. The patient presented sequentially neurotoxicity caused by two beta‐lactams antibiotics. This report meant to alert clinicians that these antibiotics have dangerous neurological effects in chronic kidney disease patients. 相似文献
3.
Participating media with an inhomogeneous index of refraction make light follow curved paths. Simulating this in a global
illumination environment has usually been neglected due to the complexity of the calculations involved, sacrificing accurate
physical simulations for efficient visual results.
This paper aims to simulate non-linear media in a more reasonable time than previous works without losing physical correctness.
Accuracy is achieved by solving the Eikonal equation of geometrical optics, which describes the path followed by a light beam
that traverses a non-linear medium. This equation is used in the context of a photon mapping extension. 相似文献
4.
L Martinez de Haro P Parrilla A Ortiz G Morales J Cifuentes D Perez D Videla 《Canadian Metallurgical Quarterly》1993,88(4):525-529
The relationship between manometric and pH-metric data was studied in a group of 50 patients with symptoms of gastroesophageal reflux. Using a multiple regression analysis, we found that the total percentage of reflux was significantly correlated to the infradiaphragmatic length and resting pressure of the lower esophageal sphincter and also to the mean amplitude of the contractile waves of the distal esophagus, thus revealing the important role of these factors in the antireflux mechanism. When the patients were divided into groups according to their manometric characteristics and the values of the various pH-metric parameters between these groups compared using a one-way analysis of variance, we found that the amplitude of the contractile waves and the percentage of deglutitions without response were related not only to the total percentage of reflux but also to the number of reflux episodes of greater than 5 min duration and to the duration of the longest episode. This shows that prolonged exposure of the esophageal mucosa to the refluxed material may be due, in part, to an alteration in the capacity for esophageal clearing. 相似文献
5.
Daniel Escolar María R. Haro Jesús Ayuso 《Journal of the American Oil Chemists' Society》2002,79(8):769-774
Four polynomial expressions are obtained that provide a good approximation and an easy, rapid calculation of the chromatic
coordinates and the chroma—L
*, a
*, b
*, and C—for the illuminant C and the standard observer, for a virgin or extra virgin olive oil; absorbance is measured at only 480
and 670 nm. These are as follows: L
*=0.556458(A480)2−2.51145A480+0.55504(A670)2−8.53016A670+98.4089; a
*=0.177372(A480)2+2.1363A480+1.43254(A670)2−0.789231A670−13.9246; b
*=−16.0277(A480)2+79.8932A480−5.06558(A670)2+3.36169A670+31.9405; C=−15.8439(A480)2+78.9312A480−5.26784(A670)2+3.56917A670+33.3927. These give acceptable results, making the method a practical alternative to the extremely laborious Commission Internationale
d’Eclairage (CIE) L
*
a
*
b
*
system, by which 391 absorbance values must be measured individually, nanometer by nanometer, before applying more complex
equations. The validity of the proposed method has been confirmed by comparison, using a set of 20 sample oils different from
the set of 25 oils used to generate the order of the equations. The variations between the values provided by the proposed
and standard methods, respectively, had a mean of 0.00 for each of the chromatic variables—L
*
, a
*
, b
*
, and C; SD were moderate (0.71, 0.52, 1.22, and 1.22, respectively); the root mean square and the R
2-terms also confirmed the validity of the method. 相似文献
6.
This study investigates the whole-body vibration exposure in kite surfing, alpine skiing, snowboarding and cycling. The vibration exposure was experimentally evaluated following the ISO 2631 guidelines. Results evidenced that the most critical axis is the vertical one. The weighted vibration levels are always larger than 2.5 m/s2 and the vibration dose values are larger than 25 m/s1.75. The exposure limit values of the EU directive are reached after 8–37 min depending on the sport. The vibration magnitude is influenced by the athletes’ speed, by their skill level and sometimes by the equipment. The large vibration values suggest that the practice of sport activities may be a confounding factor in the aetiology of vibration-related diseases. 相似文献
7.
8.
Pardo Diego Fichera Loris Caldwell Darwin Mattos Leonardo S. 《Neural Processing Letters》2015,41(1):55-69
Neural Processing Letters - This paper presents an approach to determine a model of superficial tissue temperature dynamics during continuous wave CO $$_2$$ laser irradiation. The main contribution... 相似文献
9.
10.