全文获取类型
收费全文 | 3945篇 |
免费 | 94篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 19篇 |
综合类 | 5篇 |
化学工业 | 209篇 |
金属工艺 | 37篇 |
机械仪表 | 78篇 |
建筑科学 | 5篇 |
矿业工程 | 3篇 |
能源动力 | 37篇 |
轻工业 | 45篇 |
水利工程 | 10篇 |
石油天然气 | 2篇 |
无线电 | 169篇 |
一般工业技术 | 273篇 |
冶金工业 | 3054篇 |
原子能技术 | 12篇 |
自动化技术 | 84篇 |
出版年
2024年 | 2篇 |
2023年 | 15篇 |
2022年 | 11篇 |
2021年 | 39篇 |
2020年 | 29篇 |
2019年 | 28篇 |
2018年 | 31篇 |
2017年 | 40篇 |
2016年 | 39篇 |
2015年 | 28篇 |
2014年 | 44篇 |
2013年 | 56篇 |
2012年 | 78篇 |
2011年 | 82篇 |
2010年 | 46篇 |
2009年 | 51篇 |
2008年 | 45篇 |
2007年 | 29篇 |
2006年 | 32篇 |
2005年 | 28篇 |
2004年 | 35篇 |
2003年 | 26篇 |
2002年 | 36篇 |
2001年 | 22篇 |
2000年 | 19篇 |
1999年 | 102篇 |
1998年 | 911篇 |
1997年 | 516篇 |
1996年 | 322篇 |
1995年 | 179篇 |
1994年 | 159篇 |
1993年 | 175篇 |
1992年 | 29篇 |
1991年 | 39篇 |
1990年 | 44篇 |
1989年 | 52篇 |
1988年 | 56篇 |
1987年 | 60篇 |
1986年 | 41篇 |
1985年 | 34篇 |
1983年 | 13篇 |
1982年 | 15篇 |
1981年 | 21篇 |
1980年 | 38篇 |
1979年 | 5篇 |
1978年 | 12篇 |
1977年 | 94篇 |
1976年 | 217篇 |
1975年 | 13篇 |
1955年 | 1篇 |
排序方式: 共有4042条查询结果,搜索用时 265 毫秒
31.
PH Kohek B Pakisch H Glanzer G H?ss HJ Mischinger G Wolf P Steindorfer 《Canadian Metallurgical Quarterly》1995,21(6):627-631
Forty-eight patients with non-resectable cancer of the oesophagus and oesophagogastric junction (Group A: Stage I/II, 32; Group B: Stage III/IV, 16) underwent intraluminal Iridium-192 high dose-rate afterloading therapy (5-7 Gy/session, total dose: 5-21 Gy, mean: 12.4 Gy) and external beam irradiation (Karnofsky > or = 80% 50-60 Gy/2 Gy per day; Karnofsky 60-79%: 30 Gy/3 Gy per day). Durable satisfactory palliation (intake of at least semi-solid food) was demonstrated in 96% of patients. The mean survival for group A was 19.1 months and that for group B, 6.9 months, with a 12-month survival rate of 66% (group A) and 0% (group B) (P < 0.001). Local tumour response and complication rate were significantly dose-related with a predicted response rate of 70.5%, and a complication rate of 50% at ERD 129.3 Gy. 相似文献
32.
WJ Schnedl EC Reisinger RW Lipp M Uggowitzer HJ Mischinger P Fickert GJ Krejs 《Canadian Metallurgical Quarterly》1996,23(3):220-223
We reported an operative case of bilateral coronary artery fistulae to pulmonary artery associated with a giant saccular aneurysm, the largest of which measured 30 x 30 mm. The patient was a 75 year old female who had anginal pain due to coronary steal phenomenon. A continuous murmur was detected. After establishing total cardiopulmonary bypass, two distal orifices of the fistula connected to the main pulmonary artery were closed with 5-0 polypropylene plegeted sutures. Aneurysmorrhaphy was then performed for giant saccular aneurysm. Postoperative course was uneventful. 相似文献
33.
34.
35.
HJ Epple FW Kirstein C Bojarski J Frege M Fromm EO Riecken JD Schulzke 《Canadian Metallurgical Quarterly》1997,32(4):308-314
Obliterative or constrictive bronchiolitis is characterized by narrowing of the small airways, due to submucosal and peribronchiolar fibrosis, with chronic obstruction. The vast majority of cases of bronchiolitis obliterans are associated with other diseases and only few cases are idiopathic. We report on the main computed tomography (CT) methods used study obliterative bronchiolitis, the CT findings and the differential diagnosis with other diseases. The dynamic study of alveolar ventilation with CT uses inspiratory and expiratory CT or high-resolution CT (HRCT), spiral dynamic CT or HRCT with advanced image display, ultrafast CT. In abnormal cases HRCT shows direct and indirect signs of small airways disease. The most common (> 80%) sign of obliterative bronchiolitis is the so-called mosaic oligohemia, with low attenuating lobules, caused by air trapping and best seen on expiratory CT, associated with blood flow redistribution to more normal lobules; this finding simulates the ground-glass pattern from infiltrative lung disease. Differential diagnosis is more difficult in the presence of true ground-glass patterns associated with diffuse bronchiolar obstruction and also with mosaic oligohemia due to pulmonary vascular disease and pulmonary emphysema. HRCT can distinguish these diseases and dynamic CT is more sensitive than functional tests in detecting regional abnormalities and air trapping. The combination of HRCT, rapid volumetric scanning and advanced image display is a powerful tool study the normal and abnormal features of bronchiolar function and alveolar ventilation. 相似文献
36.
37.
38.
39.
40.
W Astfalk FM H?cker HJ Kirschner G Stuhldreier P Schweizer 《Canadian Metallurgical Quarterly》1997,122(10):898-900
Since 1990, we have been conducting ambulatory pediatric surgery in an unit established solely for this purpose, supported by a team of kindergarten teachers, pediatric nurses, anesthesiologists and pediatric surgeons. This prospective investigation includes all ambulatory pediatric operations performed in our department from 1990 to 1995. In this time 3665 infants and children between the ages of 6 weeks and 18 years underwent an ambulatory operation. The ratio male to female was 4.1 to 1. The series consists of 1400 inguinal hernias, 722 inguinal testes, 191 hydroceles/funiculoceles, 75 umbilical hernias, 667 phimoses, 70 meatotomies, 59 hemangiomas, 217 endoscopies and 264 other surgical procedures. Postoperative complications defined as secondary hemorrhage, fever, obvious vomiting, urine retention and laryngospasm upon terminating anesthesia accompanied by subsequent vomiting occurred in 59 (1.6%) of all infants and children. Wound infections were seen in 0.48% (17/3517) of all patients. The recurrence rate for inguinal hernias were 0.79% and 1.12% for inguinal testes. Our experience enables us to summarize that a variety of pediatric operations can be performed today as ambulatory procedures. Nevertheless one must be prepared for the occurrence of complications and always have capacities free for inpatient care where adequate observation and treatment are available. Further improvement is necessary in quality management. In the last 20 years only a few data have been published about recurrence rates after pediatric ambulatory operations for inguinal hernias and inguinal testes. Therefore we started a prospective long- term study. 相似文献