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711.
On the basis of an abound practice of hygiene standardization, the authors have elaborated a system of fundamental tenets and premises that correspond to the requirements of a universal theory. It includes norms and standards for a living organisms and the environment. The hygiene standardization foundation is based on the principles of guarantee, social-biological balance, complex and dynamics. The tenets stated in the article confirm interrelation and character of the hygiene standards theory formulation and its prognostic function.  相似文献   
712.
The world's great wines are produced from a relatively small number of classic European cultivars of Vitis vinifera L Most are thought to be centuries old and their origins have long been the subject of speculation. Among the most prominent of these cultivars is Cabernet Sauvignon, described as "the world's most renowned grape variety for the production of fine red wine". Although now grown in many countries, Cabernet Sauvignon derives its fame from its long association with the Bordeaux region of France, where it has been grown at least since the 17th century. We present microsatellite DNA evidence for the hypothesis that Cabernet Sauvignon is the progeny of two other Bordeaux cultivars, Cabernet franc and Sauvignon blanc. Likelihood ratios support this hypothesis to a very high degree of probability. A close relationship between Cabernet Sauvignon and Cabernet franc has been suspected but the genetic contribution of Sauvignon blanc, despite its similar name, is a surprise.  相似文献   
713.
Plant disease resistance (R) genes confer an ability to resist infection by pathogens expressing specific corresponding avirulence genes. In Arabidopsis thaliana, resistance to both bacterial and fungal pathogens, mediated by several R gene products, requires the NDR1 gene. Positional cloning was used to isolate NDR1, which encodes a 660-base pair open reading frame. The predicted 219-amino acid sequence suggests that NDR1 may be associated with a membrane. NDR1 expression is induced in response to pathogen challenge and may function to integrate various pathogen recognition signals.  相似文献   
714.
Myasthenia gravis (MG) is mediated by autoantibodies against the acetylcholine receptor at the muscle endplate. Some MG patients have in addition antibodies (Ab) to the skeletal muscle proteins ryanodine receptor (RyR) and titin. We have examined GM and KM allotypes, RyR and titin Ab in 44 MG patients (37 thymoma patients and 7 non-thymoma, late-onset patients) and 292 non-MG controls to see if GM/KM allotypes associate with differences in autoantibody production. All patients had titin Ab, and 15 thymoma patients had also RyR Ab. The phenotype GM 1, 2, 3 23 5, 21 was significantly increased in the patients with titin Ab compared with the non-MG controls (chi2 = 4.93, p < 0.05). Thymoma patients with RyR Ab had a higher frequency of the GM 3 23 5 phenotype compared with RyR Ab negative patients and controls (chi2 = 7.1, p < 0.05). KM allotypes did not differ between RyR Ab positive or titin Ab positive patients and controls. GM phenotypes may thus be associated with an autoimmune response against the muscle proteins titin and RyR in MG patients.  相似文献   
715.
Insulin has pleiotropic effects on the regulation of cellular growth, differentiation, and metabolism. The biochemical events ultimately leading to cell proliferation after insulin treatment have been demonstrated in detail by numerous research groups. However, depending on cell types, it has been shown that insulin has various effects on cell proliferation. Therefore, we attempted to more critically evaluate the effect of insulin on cell proliferation in 3T3 L1 fibroblasts. In this study, we investigated insulin's effect on cell proliferation by using [3H]thymidine incorporation, flow cytometry, and cell counting. In 3T3 L1 fibroblasts studied in 0.5% serum, insulin induced a two-fold increase in [3H]thymidine incorporation over at 48 h, and the maximal rate of DNA synthesis was observed during 8-12 h incubation. The flow cytometric analysis also showed that insulin increased the cell population in the S phase. After insulin treatment for 48 h, cell numbers increased approximately 45% in comparison with 0.5% serum control. Cell division was found to occur only once in 60 h after staining 3T3 L1 fibroblasts with carboxyfluorescein diacetate succinimidyl ester (CFSE). Taken together, this data indicates that insulin stimulated the transit from the G0/G1 to S phase, progressed the cell cycle through the G2/M phase, and increased the cell number. However, under our experimental conditions, cells divided only once in 60 h in the presence of insulin.  相似文献   
716.
The authors report a case of carcinoma in an ex pleomorphic adenoma of the parotid gland that was recently referred to their attention. This form of carcinoma is not very frequent and in the literature it is reported in a percentage of cases ranging from 1.5 to 12%. The pathogenesis of this neoplasia is controversial and at the present state of the art there are authors who support the hypothesis of a malignant transformation of a previous pleomorphic adenoma, and those who sustain the onset of the tumour ex novo. At present, there is a tendency to differentiate the carcinoma ex pleomorphic adenoma from the malignant mixed tumour: the histological analysis of the former in fact shows a benign stromal component typical of pleomorphic adenoma associated with a malignant epithelial component, whereas in the malignant mixed tumour both the mesenchymal and epithelial components are malignant. The authors use this case report as a starting point to review their 20-year experience, of pleomorphic adenoma in order to evaluate the behaviour of this tumour, above all in relation to the phenomenon of recidivation and cancerization. They report recidivation in 3.5% of cases and no malignant degeneration. The surgical approach used varied depending on the site and size of the neoformation, as well as on whether the tumour was primary or recurrent.  相似文献   
717.
One biological effect of nitric oxide (NO) has been believed to be exerted through induction of the ADP-ribosyltransferase activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Though this notion is based on the finding that NO increases the auto-ADP-ribosylation of GAPDH, controversial data have also been reported. To determine whether or not NO really activates ADP-ribosylation, we re-examined the NO-induced modification of GAPDH with NAD+. GAPDH was modified equally with [adenosine-14C]NAD+ and [carbonyl-14C]NAD+, indicating that the glycoside bond of NAD+ between ADP-ribose and nicotinamide is intact. The release of nicotinamide from NAD+ was not evident during incubation of GAPDH with [carbonyl-14C]NAD+. Thus, the modification of GAPDH is apparently not ADP-ribosylation. In addition, we found that basal and glyceraldehyde-3-phosphate-induced modifications of GAPDH, both of which have also been explained as ADP-ribosylation, were not ADP-ribosylation, and that the modification of GAPDH in the absence and presence of NO or GA3P was distinct in the dithiothreitol effect or resistance to HgCl2.  相似文献   
718.
OBJECTIVE: To investigate the relationship between physical activity, leisure time activities and dietary habits in adolescents. PATIENTS AND METHODS: We have studied 541 girls and 537 boys from 24 schools. Physical activity, leisure time activities and dietary habits were assessed by 3 different questionnaires, taking into account one week of normal activity and diet. RESULTS: Foods such as milk, fish, meat, egg, fruits, vegetables, pasta and snacks were consumed more frequently in children who spent more time doing sport, but difference were not statistically significant. Boys who spent more time watching T.V. ate greater amounts of almost all foods (p < 0.05). In girls, we have observed the same results, but differences were not statistically significant. CONCLUSIONS: Sports and T.V. watching are both related to a greater amount of food intake From our results we can deduce that in order to prevent obesity, and other cardiovascular risk factors, we must improve food intake related with sedentary habits.  相似文献   
719.
Subspecies defining the maturation pathway of bovine chymotrypsinogen to alpha-chymotrypsin have been separated in a single chromatographic run by affinity to iminodiacetic acid-Cu(II) [IDA-Cu(II)] immobilized onto Novarose. A major highlight of the elution pattern is that, as maturation proceeds, these subspecies exhibit a correlated increase in affinity toward IDA-Cu(II). This behavior is analyzed by a combination of physicochemical and molecular modeling techniques to assess the contribution of the two histidines present in chymotrypsins, at positions 40 and 57 on the protein surface. Catalytic His-57 features adequate surface accessibility to serve as a ligand to IDA-Cu(II), but its participation is clearly ruled out by specific chemical modification. In contrast, His-40, whose side chain is buried in the crystal structures of both zymogen and mature enzyme, surprisingly proves the most plausible candidate as an electron donor to IDA-Cu(II). This apparent conflict between histidine accessibility and their implication in IDA-Cu(II) recognition has been rationalized on the basis of their flexibility and/or hydrogen-bonding status, with the following outcome. First, histidine constitutes a useful reporter group for subtle protein conformational fluctuations. Second, static accessibility computation alone provides no unequivocal guideline as to whether a protein residue can serve as a ligand. Third, this study is the first to document the occurrence of a screening effect due to hydrogen bonding of an otherwise "accessible" histidine. A significant corollary to this finding would be that the catalytic histidine is rigidly entrapped in a remarkably strong hydrogen-bonding network, a situation that may pertain to mechanistic aspects of catalysis.  相似文献   
720.
A 2 x 2 x 4 factorial design was used to study variation of protein and fat contents in beef broths as affected by cut type (flank, shank), salt treatments (addition of salt to the medium, no salt), and initial temperatures of simmering (25, 70, 75, and 100 degrees C). Flank portions yielded slightly more protein (0.29 g/100 mL) and had three-fold less fat (0.39 g/mL) than those of shank (0.25 and 1.12 g/mL, respectively) (P < 0.05). No linear relationship of temperature and amount of extractable components was observed, but it was clear that the greatest protein extraction was accomplished when meat was immersed in cooking water at boiling point (P < 0.05). In general, salting of water reduced fat content of beef broths. However, a significant Salting x Cut type interaction showed this effect was only present in shanks (P < 0.05). Conversely, the reducing effect (P < 0.05) of salting on amount of protein extracted from flank was not observed in shanks. Based on these data, we conclude that larger amounts of protein and less fat could be transferred from meat pieces to the medium by immersing beef in salted water at the boiling point.  相似文献   
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