全文获取类型
收费全文 | 1455篇 |
免费 | 14篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 65篇 |
金属工艺 | 5篇 |
机械仪表 | 12篇 |
建筑科学 | 35篇 |
矿业工程 | 6篇 |
能源动力 | 18篇 |
轻工业 | 32篇 |
水利工程 | 4篇 |
石油天然气 | 3篇 |
无线电 | 35篇 |
一般工业技术 | 64篇 |
冶金工业 | 1144篇 |
原子能技术 | 6篇 |
自动化技术 | 39篇 |
出版年
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2016年 | 9篇 |
2015年 | 9篇 |
2014年 | 6篇 |
2013年 | 31篇 |
2012年 | 11篇 |
2011年 | 10篇 |
2010年 | 13篇 |
2009年 | 12篇 |
2008年 | 14篇 |
2007年 | 9篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 12篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 35篇 |
1998年 | 330篇 |
1997年 | 198篇 |
1996年 | 137篇 |
1995年 | 65篇 |
1994年 | 75篇 |
1993年 | 67篇 |
1992年 | 17篇 |
1991年 | 14篇 |
1990年 | 10篇 |
1989年 | 21篇 |
1988年 | 17篇 |
1987年 | 19篇 |
1986年 | 20篇 |
1985年 | 34篇 |
1984年 | 19篇 |
1983年 | 15篇 |
1982年 | 12篇 |
1981年 | 13篇 |
1980年 | 15篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 40篇 |
1976年 | 81篇 |
1974年 | 2篇 |
1960年 | 2篇 |
1957年 | 2篇 |
1920年 | 2篇 |
排序方式: 共有1470条查询结果,搜索用时 0 毫秒
1.
2.
3.
J.E. Harding 《Journal of Constructional Steel Research》1985,5(4):321
4.
A Notghi R Hutchinson D Kumar NB Smith LK Harding 《Canadian Metallurgical Quarterly》1994,35(7):976-981
Segmental colonic transit has been measured in 101 patients. Two MBq of 111Indium absorbed on resin pellets and encapsulated in an enteric coated capsule was given at 7 00 am. Hourly images during the first day, and three images during each subsequent day were acquired for up to three days. Using all scan and patient data the scans were categorised in one of the five patterns of colonic transit: normal, rapid, right delay, left delay, or generalised delay. The geometric centres and per cent activity at each time point was compared between the five groups of colonic transit patients to find the best time for imaging and so to distinguish the five groups. During the first day, early images did not help in diagnosis of patterns of transit, however, in the later images (six hours onwards after the ingestion of the activity) the rapid transit groups could be identified. Images at 27 and 51 hours were both required to distinguish all five groups of patients from each other. Only in the 'normal' transit patients was there some excretion of the activity during the course of the second day, otherwise there was no difference in the images taken in the course of a day (second or third day). A simplified protocol requires a minimum of three images to distinguish all five patterns of colonic transit. The activity should be ingested in the morning (7 00 am) and the first image taken at the end of the working day (8-10 hours after ingestion), the second image on the morning of the second day, and the third image during the course of the third day. This simple protocol would provide all the clinically relevant information necessary for correct classification of the colonic transit. 相似文献
5.
R Marana GF Catalano P Caruana F Margutti L Muzii S Mancuso 《Canadian Metallurgical Quarterly》1997,12(9):1935-1938
The efficacy of an oxidized regenerated cellulose barrier (Interceed) in reducing postoperative adhesion formation and improving reproductive outcome after ovarian surgery was evaluated in a prospective randomized trial. Twenty-nine New Zealand White female rabbits were submitted to a mid-line laparotomy and a standardized surgical incision was made on both ovaries. At random, one ovary was entirely wrapped in a sheet of Interceed, whereas the contralateral ovary was left uncovered. Four weeks following surgery, the rabbits were mated with a male of proven fertility. Two weeks later, a second-look laparotomy was performed by a blinded observer who evaluated the incidence and score of adhesions, the number of corpora lutea in each ovary, the number of embryos in the ipsilateral uterine horn and also calculated the nidation index for each side. Adhesions were observed in 66% of Interceed-covered and in 97% of control ovaries (P < 0.0001). The adhesion score on the Interceed side was significantly lower than on the control side. The nidation index for the Interceed side was significantly higher than for the control side. The authors conclude that, in the rabbit model, Interceed significantly reduces the incidence and score of postoperative ovarian adhesions and significantly improves reproductive outcome. 相似文献
6.
GF Gualdi MG Ferriano E Casciani C Pirolli E Polettini 《Canadian Metallurgical Quarterly》1997,148(5-6):209-224
In this report we reviewed the role of Ultrasonography, Computed Tomography, Magnetic Resonance and 99Tc-Sestamibi Scintigraphy for the detection of abnormal parathyroid glands in patients with biochemical evidence of hyperparathyroidism. We also report our personal experience with CT and RM. 相似文献
7.
8.
M Divaris M Rosenstiel M Slama GF Cancemi JC Bertrand F Guilbert 《Canadian Metallurgical Quarterly》1996,97(3):178-189
The cardiovascular effects of a partially purified extract of fish oil, enriched in the n-3 series fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were studied in stroke-prone spontaneously hypertensive rats (SHR-SP) fed with high- and low-sodium diets during 5 weeks. Addition of salt to the low-salt control diet at a level commonly found in human food items (6% NaCl of the dry weight of the diet) produced a remarkable rise in blood pressure, an increase in left ventricular weight-to-body weight ratio (LVH-index) and an increase in kidney weight-to-body weight ratio (RH-index). Fish oil (20% of the dry weight of the diet) did not significantly influence the blood pressure or LVH-index or RH-index during the low-salt control diet. However, fish oil completely prevented the remarkable rise in blood pressure and clearly antagonized the rise of both LVH- and RH-indices, induced by the high-salt diet. The fish oil supplementation increased the levels of the polyunsaturated fatty acids of the n-3 series and decreased those of the n-6 series in plasma and kidney, irrespective of the salt content of the diet. Fish oil lowered serum thromboxane B2 concentration by approximately 75%. During the high-salt diet, fish oil markedly decreased water intake and urine volume, and increased urinary sodium concentration by about 60%. Our findings show that, in addition to an antihypertensive effect, fish oil also decreases LVH and RH. These effects appear to be due to an improved ability to excrete sodium and could be explained by the observed changes in the fatty acid composition and metabolism. 相似文献
9.
H Bensahel P Souchet GF Pennecot Y Desgrippes 《Canadian Metallurgical Quarterly》1994,120(5):298-9; discussion 300
Current work on disease states involving the patella has led to increased interest in patellar instability. We reviewed a series of patellar luxations. True trauma-induced luxations are rare. Most cases are recurrent luxations in subjects with a morphological anomaly of the knee extensor system. Because of the growth cartilages, selective therapeutic techniques are needed to stabilize the patella. Recurrent or permanent luxations of the patella result from congenital malformations of the muscles or skeleton. A complete MRI study is highly indicated. The patella can be correctly realigned by surgical release. In cases with femoropatellar dysplasia, which is not specific for children, well conducted rehabilitation therapy often leads to favourable outcome. 相似文献
10.