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51.
OBJECTIVE: To determine whether a Pasteurella haemolytica A1 mutant that is unable to produce membrane lipoproteins has reduced susceptibility to complement-mediated killing, and to characterize the mutant strain. SAMPLE POPULATION: 12 sera from cattle resistant to P haemolytica challenge exposure after vaccination with P haemolytica or its antigens, or after natural exposure. PROCEDURES: Complement-mediated killing assays were performed, using wild-type and mutant strains and, as antibody source, various immune sera from cattle that were resistant to P haemolytica challenge exposure. Antibody response to whole-cell antigens produced by mutant and wild-type strains, production of outer membrane proteins and iron-regulated outer membrane proteins by the 2 strains, and growth of the 2 strains in various media were analyzed. RESULTS: Compared with wild-type P haemolytica, the lipoprotein mutant strain had increased susceptibility to bovine complement-mediated killing. Aside from the lipoproteins that are not produced by the mutant, immunoblot analysis did not reveal differences between immunoreactive antigens that are produced by the 2 strains. Some iron-regulated, outer membrane proteins, which usually are only produced by P haemolytica under iron-deficient conditions, were produced constitutively by the mutant. The mutant grew to a lower final cell density and at a lower rate under conditions likely to reflect those encountered in vivo. CONCLUSIONS: Lack of 3 membrane lipoproteins resulted in enhanced susceptibility to bovine complement-mediated killing. Site-specific mutagenesis of genes encoding P haemolytica membrane lipoproteins alters production of iron-regulated outer membrane proteins by P haemolytica. Growth characteristics of the mutant suggested that it may have reduced capacity for survival in vivo.  相似文献   
52.
Magnesium sulphate (magnesium), an essential anti-oxidant macromineral, was evaluated for its effects on the clastogenic and biochemical changes induced by Adriamycin (ADM) in Swiss albino mice. Male mice were treated orally with different doses (125, 250 and 500 mg/kg body weight/day) of magnesium sulphate for 7 days. Some of these mice were injected intraperitoneally with ADM (8 mg/kg body weight). Multiple sampling (12, 24 and 48 h) were carried out after the last treatment in different experiments. The animals were sacrificed under ether anaesthesia. The concentrations of magnesium were determined in plasma and liver tissue. Femoral marrow cells were collected and screened for the frequency of micronuclei and the ratio of polychromatic erythrocytes to normochromatic erythrocytes. Furthermore the proteins, nucleic acids, malondialdehyde (MDA) and non-protein sulphydryl (NPSH) levels were estimated in hepatic cells. The magnesium sulphate treatment did not affect the magnesium concentrations in plasma and liver tissue. The treatment also failed to cause any significant clastogenic, cytotoxic and biochemical changes. Pretreatment with magnesium sulphate showed no alterations in plasma and hepatic tissue levels of magnesium. Nevertheless the pretreatment was found to inhibit the ADM-induced micronuclei without any alteration in its therapeutic efficacy. The proteins, DNA, RNA and MDA levels in the hepatic cells of these animals were increased and the NPSH concentrations were reduced. The anticlastogenic nature of magnesium sulphate appears to be related to its pretreatment which might have averted the free-radical-mediated pathogenesis induced by ADM.  相似文献   
53.
54.
13 patients aged 39 to 60 years with coronary atherosclerosis confirmed at selective coronary angiography combined with primary hyperlipidemia (phenotypes 2a and 2b) received enduracin in a dose 1500 mg/day. As a result of the treatment total cholesterol (TC) and LDL cholesterol lowered by 10.3 and 13.1%, respectively, whereas HDL cholesterol rose by 15.2%. Half of the patients demonstrated activation of hepatic transaminases, but discontinuation of the drug was not necessary. In 3 out of 4 patients after 2 years of enduracin treatment stabilization of atherosclerosis was observed. Thus, long-term enduracin is able to inhibit progression of atherosclerosis in coronary heart disease patients.  相似文献   
55.
The triflates and pivalates of 3 alpha-hydroxymethyl-6-substituted-2,2-dimethylpenam sulfones 3, 5; methyl and benzyl 6-substituted penicillanates 6-9 and 3-exo-methylene-6-substituted-2,2-dimethylpenam sulfone 4 were synthesized. These novel compounds were evaluated as elastase inhibitors using porcine pancreatic elastase. The effects that structural modifications of substituents on C-3 and C-6 in the penam nucleus have on elastase activity were examined and several similarities and distinctions were identified when compared to the reported penicillin esters and amides elastase inhibitors.  相似文献   
56.
11 patients with severe bronchial asthma entered a randomized trial of glucocorticosteroid budesonide of Russian produce. Of them 6 patients received inhalations of budesonide (800 micrograms/day for 6 months), 5 control patients did not receive the drug. As shown by investigations of external respiration and bronchoalveolar lavage with estimation of cytogram, metacholine provocative tests, fiber bronchoscopy, budesonide inhalations relieved clinical symptoms of asthma, bronchial hyperreactivity and inflammation.  相似文献   
57.
A unique case of generalized bacillary angiomatosis (BA) in a patient who died of HIV infection is described. Apart from widely spread skin lesions there were also manifestations in the brain, lungs, heart, esophagus and intestine. Gram-negative bacteria were found in the histological sections. Oval and roundish bacteria with a predominantly perivascular location were found electron microscopically in the archives material.  相似文献   
58.
Condition was studied of collective specific immunity against diphtheria in vaccinated children who ranged from 2 to 15 years old, living in the industrial region of Pridneprovye, with special reference for the degree of the technogenous environmental pollution. To determine specific cellular sensibilization to diphtherial antigen. LAIT was used for the first time. The studies made showed that in a region under health-hazard conditions lower level of antitoxic antidiphtherial immunity occurs more frequently than in non-polluted areas (twice as much of the values), which fact suggests that technologeous pollution may have a suppressive effect on formation of postvaccinal immunity. Apart from measuring the level of specific antibodies for control of the formation of the immune responsiveness to be monitored you may use LAIT and measure levels of R-proteins.  相似文献   
59.
Values of hour excretion of vitamins B1, B2, B6 and PP with urine in children of 9-13 years, studied under conditions of normal consumption of these vitamins, were estimated considering the correlation between the vitamins B concentration in blood and excretion of their metabolites with urine as well as using these parameters dependence on content of the vitamins in daily ration; for this purpose 35 adult persons and 31 children of both sexes were examined. Normal rate of riboflavin excretion with urine constituted 10-11 micrograms/h in children of this age, while of thiamine-11-12 micrograms/h. Under conditions of normal thiamine consumption, activity of erythrocyte transketolase, measured after preinactivation of transaldolase, exceeded 35 mumol/h/I ml of erythrocytes. Rates of excretion with urine of 4-pyridoxic acid and I-methyl nicotinamide were similar both in children and in adult persons and were equal to more than 40 micrograms/h and 400-600 micrograms/h, respectively.  相似文献   
60.
M2, an acid-activated ion channel, is an influenza A virus membrane protein required for efficient nucleocapsid release after viral fusion with the endosomal membrane. Recombinant M2 slows protein traffic through the Golgi complex (Sakaguchi, T., Leser, G. P)., and Lamb, R. A. (1996) J. Cell Biol. 133, 733-47). Despite its critical role in viral infection, little is known about the subcellular distribution of M2 or its fate following delivery to the plasma membrane (PM). We measured the kinetics of M2 transport in HeLa cells, and found that active M2 reached the PM considerably more slowly than inactive M2. In addition, M2 delayed intra-Golgi transport and cell surface delivery of influenza hemagglutinin (HA). We hypothesized that the effects of M2 on transport through non-acidified compartments are due to inefficient retrieval from the trans-Golgi of machinery required for intra-Golgi transport. In support of this, acutely activated M2 had no effect on intra-Golgi transport of HA, but still slowed HA delivery to the PM. Thus, M2 has an indirect effect on early transport steps, but a direct effect on late steps in PM delivery. These findings may help explain the conflicting and unexplained effects on protein traffic observed with other perturbants of intraorganelle pH such as weak bases and inhibitors of V-type ATPases.  相似文献   
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