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   551篇
  免费   1篇
  国内免费   1篇
综合类   1篇
化学工业   2篇
机械仪表   2篇
建筑科学   1篇
矿业工程   9篇
轻工业   18篇
石油天然气   2篇
无线电   40篇
一般工业技术   6篇
冶金工业   466篇
自动化技术   6篇
  2018年   1篇
  2015年   1篇
  2013年   4篇
  2012年   3篇
  2011年   3篇
  2010年   3篇
  2009年   1篇
  2008年   2篇
  2007年   3篇
  2006年   3篇
  2005年   3篇
  2004年   1篇
  2003年   1篇
  2002年   1篇
  2001年   1篇
  2000年   7篇
  1999年   9篇
  1998年   151篇
  1997年   76篇
  1996年   47篇
  1995年   35篇
  1994年   30篇
  1993年   26篇
  1992年   7篇
  1991年   1篇
  1990年   6篇
  1989年   6篇
  1988年   6篇
  1987年   7篇
  1986年   8篇
  1985年   2篇
  1984年   2篇
  1983年   3篇
  1982年   3篇
  1981年   3篇
  1980年   8篇
  1978年   3篇
  1977年   20篇
  1976年   53篇
  1975年   1篇
  1964年   1篇
  1954年   1篇
排序方式: 共有553条查询结果,搜索用时 15 毫秒
21.
22.
23.
AIM: This study of trimetasidine effects on plasmic hemostasis and blood biochemistry in patients with chronic heart failure (CCF) of NYHA functional class II-III. MATERIALS AND METHODS: This study enrolled 30 patients (24 males and 6 females) aged 40-72 years with class II-III CCF, postinfarction cardiosclerosis and ejection fraction under 40%. Previously the patients received perindopril (the inhibitor of angiotensin converting enzyme) in daily dose 2-4 mg, on-demand digoxin and diuretics. Trimetasidine was given in a daily dose 60 mg for 6 months. Before and after the treatment the patients' blood was examined for: levels of factors VII and X of antithrombin III coagulation, soluble fibrinomonomeric complexes (SFMC), fibrinogen, glucose, uric acid, creatinines, total cholesterol, high density lipoprotein, triglycerides, AST, ALT, LDH, acid phosphotase, gamma-GT, sodium, potassium, activated partial thrombin time. RESULTS: Initially, the patients had a 23.9% increase in the levels of factors VII and X, a 14.3% decrease of antithrombin III, 29.8 and 227.6% rise in concentrations of fibrinogen and SFMC, respectively, compared to controls. Aftertreatment values of fibrinogen, factors VII and X, SFMC fell by 21.1, 17 and 35.5%, respectively. The thrombin time arose by 17.9% (p > 0.05). Insignificant inhibition was registered in the activity of acid phosphotase and gamma-GT. Glucose, AST, ALT, LDH levels remained unchanged. Plasma creatinine tended to lowering. Total cholesterol insignificantly increased at high levels of HDL cholesterol (p > 0.05) and reduced levels of triglycerides (p > 0.05). CONCLUSIONS: Trimetasidine therapy, given after conventional treatment with diuretics, digoxin, inhibitor of angiotensin-converting enzyme, aspirin has a beneficial effect in patients with circulatory deficiency through improving hemostatic and biochemical parameters.  相似文献   
24.
We reviewed the use of a low radiation portable fluoroscopy unit in 100 patients. The most common indication was closed reduction of distal radial fractures. Fracture and joint stability were assessed on the real-time monitor and stored on videotape. Static images were stored on thermographic paper. Fluoroscopically guided joint injections and localization of implants, foreign bodies and bone tumours were performed. Fluoroscopy is a useful adjunct to arthroscopic assisted fracture reduction and other arthroscopic procedures such as distal ulnar resection. These new generation units produce superior resolution images, are easy to manoeuvre and do not require a radiographer.  相似文献   
25.
The presence of octoxynol from dried bear-bile was examined. Octoxynol was coextracted when glycolipids by Folch-Suzuki partition method. Octoxynol formed mixed-micelles with glycosphingolipids. The glycolipids were purified by DEAE-Sephadex A-25 column chromatography. The fractions containing mixed micelles were obtained from linear gradient solvent of 0.05M-0.5M ammonium acetate in methanol. HPLC ( Bondapak-NH(2) - linked to a Bondapak-C(18) column) chromatogram showed five peaks. Two possible structures for the fourth peak fraction were proposed as (CH(3))(3)C-CH(2)-C(CH(3))(2)-C(6)H(4)-OR and (CH(3))(3)C-C(CH(3))(2)-CH(2)-C(6)H(4)-OR by NMR spectroscopy. The structure was further confirmed by electrospray tandem mass spectrometry (ESI MS/MS). The spectrum showed a protonated molecule at m/z 559 and three different series of ions with mass difference of 44 were detected in the MS/MS spectrum. Therefore, the structure of the fourth peak fraction from HPLC was confirmed as octoxynol, (CH(3))(3)C-CH(2)-C(CH(3))(2)-C(6)H(4)-(OCH(2)-CH(2))n-OH, based on mass spectrometry and NMR spectroscopy.  相似文献   
26.
Human, rat, and dog phase I and phase II xenobiotic metabolism in precision-cut liver slices and freshly isolated hepatocytes was compared using a range of substrates. Carbamazepine (50 microM) and styrene (2 mM) were used as probes to study the maintenance of cytochrome P450 and epoxide hydrolase-mediated metabolism in male Sprague-Dawley rat, precision-cut liver slices and hepatocytes. Carbamazepine metabolism in both models resulted in the formation of the bioactive 10,11-epoxide (KM = 766 microM and Vmax = 2.5 pmol/min/mg protein in precision-cut slices). Epoxide formation was higher (2.4-fold) in hepatocytes than slices. Styrene was deactivated to styrene diol at a higher rate in hepatocytes (9.7-fold) than slices. The lower rate of metabolism in slices compared with hepatocytes confirms our previous observations using testosterone, 7-ethoxycoumarin, 1-chloro-2,4-dinitrobenzene and 2-(5'-chloro-2'-phosphoryloxyphenyl)-6-chloro-4-(3H)-quinazolinone in the rat. Testosterone 6 beta-hydroxylation in human liver slices was similar to cultured hepatocytes, but lower than in freshly isolated hepatocytes. 7-Ethoxycoumarin O-deethylation was higher in freshly isolated human hepatocytes, as was the ratio of glucuronide to 7-hydroxycoumarin. Testosterone hydroxylations, 7-ethoxycoumarin O-deethylation, and 1-chloro-2,4-dinitrobenzene conjugation were also lower in male beagle dog slices, compared with freshly isolated hepatocytes. Attempts at long-term preservation of dog liver slices using vitrification and storage for up to 9 days at -196 degrees C resulted in the retention of phase I and phase II metabolism, although conjugation was lower than in freshly prepared slices. Xenobiotic metabolism in short-term incubations is consistently lower in dog and rat precision-cut slices than in freshly isolated hepatocytes; whereas, in humans, this quantitative difference is partly hidden by the large interindividual variation.  相似文献   
27.
28.
29.
Under observation there were 78 patients aged 41 to 70 years suffering from the glossalgia syndrome, as well as 25 clinically healthy subjects. An activation of the sympathoadrenal system was revealed in the patients. This was ascertained on the basis of the data on vanillylmandelic acid excretion with the urine. The excretion of that acid is known to be dependent on the intensity of the paraesthesias, the duration of the ailment and the character of concurrent visceral diseases. The results obtained are regarded as evidences of the participation of the vegetative nervous system in the mechanism of the glossalgia syndrome development.  相似文献   
30.
PURPOSE OF STUDY: To assess whether selected periapical radiographs, taken according to High Yield Criteria, can reveal as much intra-osseous pathology as universal panoramic screening. POPULATION STUDIED: The records of 1101 RAF recruits enlisted in 1988-89, average age 19 years (range 16-26). METHODS: The clinical records and bitewing radiographs of the recruits were examined and the requirement for periapical radiographs determined according to high yield criteria. A template, cut out to simulate the area covered by a periapical bitewing radiograph, was placed over the suspect region on the panoramic film and any findings found within the template recorded. The entire dental panoramic tomograph was then examined on a masked screen under 2X magnification and any further findings recorded. FINDINGS: There was a considerable number of findings reported, including three large isolated radiolucent areas, 75 periradicular radiolucent areas, four probable cysts and 1187 unerupted mandibular third molars. However, when the clinical significance of these 'lesions' was assessed only those related to dental causes appeared to have significant clinical implications and the results indicated that these could have been detected by selective radiology. CONCLUSION: This study showed that the only pathology which occurs frequently enough to justify radiographic screening of the jaws in young adults is related to teeth. It seems probable that this type of pathology can be at least as well detected by selective periapical screening, using high yield criteria, as is possible by universal panoramic screening.  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