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101.
102.
J Sketelj N Crne-Finderle B Strukelj JV Trontelj D Pette 《Canadian Metallurgical Quarterly》1998,18(6):1944-1952
Acetylcholinesterase (AChE) mRNA levels are severalfold higher in fast rat muscles compared with slow. We hypothesized that AChE mRNA levels and AChE activity in the neuromuscular junction depend on a specific nerve-induced pattern of motor unit activation. Chronic low-frequency stimulation, mimicking the activation pattern in slow muscles, was applied to fast muscles in rats. Molecular forms of AChE were analyzed by velocity sedimentation, and AChE mRNA levels were analyzed by Northern blots. AChE mRNA levels in stimulated fast muscles dropped to 10-20% of control after 1 week and became comparable to those in slow soleus muscles. The activity of the junctional A12 AChE form in 35 d stimulated fast muscles decreased to 56% of control value, reaching that in the soleus muscle. Therefore, synaptic AChE itself depends on the muscle activation pattern. Complete inactivity after denervation also decreased the AChE mRNA level in fast muscles to <10% in 48 hr. In contrast, profuse fibrillations observed in noninnervated immature regenerating muscles maintain AChE mRNA levels at 80% of that in the innervated fast muscles. If protein synthesis was inhibited by cycloheximide, AChE mRNA levels in 3-d-old regenerating muscle, still containing myoblasts, increased approximately twofold. No significant increase after cycloheximide application was observed either in denervated mature fast muscles or in normal slow muscles. Low AChE mRNA levels observed in those muscles are probably not caused by decreased stability of AChE mRNA as demonstrated in myoblasts. 相似文献
103.
MA Martínez-Cuesta L Moreno JM Piqué J Bosch J Rodrigo JV Esplugues 《Canadian Metallurgical Quarterly》1996,111(3):727-735
BACKGROUND & AIMS: beta-Adrenergic relaxation seems to be mediated by nitric oxide. The aim of this study was to evaluate changes induced by portal hypertension in beta 2-adrenergic vasorelaxation. METHODS: Isolated rat mesenteric veins were relaxed by salbutamol, and nerve-mediated vasocontractions were induced by electrical field stimulation. Responses were evaluated in the presence of NG-nitro-L-arginine methyl ester (L-NAME) or tetrodotoxin. Immunocytochemical techniques were used for localization of neuronal NO synthase. RESULTS: Salbutamol-induced relaxations were decreased in rings from portal-hypertensive animals. L-NAME reduced these relaxations, but its effects were more pronounced in sham-operated rats. Tetrodotoxin decreased the effect of salbutamol only in rings from sham-operated animals. Combination of L-NAME and tetrodotoxin did not exert a greater effect than either of these agents alone. Veins from portal-hypertensive animals were more sensitive to S-nitroso-N-acetyl penicillamine. L-NAME increased vasocontractions by electrical stimulation only in rings from sham-operated rats. Veins from portal-hypertensive animals exhibited a specific degeneration of NO-containing nerve endings. CONCLUSIONS: beta 2-Adrenergic relaxation is impaired in mesenteric veins from portal-hypertensive rats, possibly as a result of a defective neuronal release of NO. 相似文献
104.
In a prospective study of 6301 surgical patients in a university hospital, we examined the strength of association between ASA physical status classification and perioperative risk factors, and postoperative outcome, using both univariate analysis and calculation of the odds ratio of the risk of developing a postoperative complication by means of a logistic regression model. Univariate analysis showed a significant correlation (P < 0.05) between ASA class and perioperative variables (intraoperative blood loss, duration of postoperative ventilation and duration of intensive care stay), postoperative complications and mortality rate. Univariate analysis of individual preoperative risk factors demonstrated their importance in the development of postoperative complications in the related organ systems. Estimating the increased risk odds ratio for single variables, we found that the risk of complication was influenced mainly by ASA class IV (risk odds ratio = 4.2) and ASA class III (risk odds ratio = 2.2). We conclude that ASA physical status classification was a predictor of postoperative outcome. 相似文献
105.
JV Pothuluri JB Sutherland JP Freeman CE Cerniglia 《Canadian Metallurgical Quarterly》1998,64(8):3106-3109
The fungus Cunninghamella elegans was used to biotransform 6-nitrochrysene, a mutagen that is a widespread environmental contaminant. After 6 days, 74% of the 3H-labeled 6-nitrochrysene added had been metabolized to two isomeric sulfate conjugates. These conjugates were separated by high-performance liquid chromatography and identified by UV-visible, 1H nuclear magnetic resonance, and mass spectral techniques as 6-nitrochrysene 1-sulfate and 6-nitrochrysene 2-sulfate. 相似文献
106.
JV López-Mut M Cubells S Campos V Miranda P Rivera 《Canadian Metallurgical Quarterly》1998,23(6):558-559
Jejunogastric intussusception is a rare complication of gastric surgery. We report a case in a 41-year-old woman subjected to gastrojejunostomy with truncal vagotomy 3 years before for pyloric stenosis. The jejunogastric intussusception was diagnosed by upper gastrointestinal series, ultrasonography, and computed tomography. Surgical management consisted of reduction and fixation. Treatment should be as early as possible to prevent gangrene of the invaginated segment. 相似文献
107.
108.
In the course of biotransformation reactions catalyzed both by cytochrome P450 and by conjugating enzymes, drug-derived reactive metabolites and active oxygen species can appear that may escape the detoxification process, initiating radical chain reactions (e.g., lipid peroxidation), covalently binding to macromolecules (proteins, DNA), or impairing the energetic balance of cells. This is usually followed by alterations of ion homeostasis that precede irreversible biochemical changes and cell death. There are, however, cellular mechanisms of defense that prevent, or repair, the damage caused by these reactive intermediates. Ultimately it is the balance between bioactivation, detoxification, and defense mechanisms that determines whether a compound will or will not elicit a toxic effect. Cultures of hepatocytes, including those of human origin, can be used to elucidate the mechanisms of drug toxicity. This is illustrated in the study of the mechanism of hepatotoxicity by diclofenac. Much less cytotoxicity is observed in nonmetabolizing hepatomas than in hepatocytes. The observed cell dysfunction parallels the biotransformation of the drug, and particularly the formation of the minor metabolite N,5-dihydroxydiclofenac by hepatocytes. This compound is able to inhibit mitochondrial ATP synthesis in hepatocytes. 相似文献
109.
110.
A survey of laboratory records was made to assess the value of the precipitin test and isolation methods in the diagnosis of farmer's lung disease and also to determine its prevalence in the farming population of Somerset. A link was established between the clinical diagnosis as written on the form that accompanied the specimen and the actual number of positive laboratory diagnoses made. Fifty (43%) of the clinically diagnosed patients were serologically positive for farmer's lung during a four-year period. If the clinically diagnosed but serologically negative cases of farmer's lung disease are added to this number, a prevalence of about 23 per 1000 of the farming population of Somerset is obtained. 相似文献