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1.
LY171883, a peroxisome proliferator and leukotriene D4-antagonist, induced a statistically significant increase in the number of hepatic lesions in B6C3F1 female mice in a 2 year oncogenicity study at dietary doses of 0.0225% and 0.075%. The mutation frequency and spectrum of the 61st codon of H-ras was determined for 64 independent, archived lesions from the LY171883 2 year oncogenicity study using the polymerase chain reaction (PCR), allele specific oligo hybridization (ASO) and DNA sequencing. Results showed 41 (64%) of these lesions had mutations at the 61st codon (16/21 hepatocellular carcinomas, 4/10 hepatocellular adenomas, 19/26 focal hepatocellular hyperplasias and 2/7 focal hepatocellular atypia). These mutations consisted of 18 C-A transversions, 16 A-G transitions and seven A-T transversions. Compared to the mutation frequency for spontaneously occurring archival B6C3F1 hepatic lesions (41%), the frequency of LY171883 lesions (64%) was significantly higher (P < 0.01). The frequencies of H-ras 61st codon mutations among the LY171883 lesion types (hepatocellular carcinomas 76%, hepatocellular adenomas 40%, focal hepatocellular hyperplasias 73% and hepatocellular atypia 29%) were also significantly different (P = 0.035). In contrast, spontaneous lesions showed no statistical difference in the frequencies of mutation among lesion types (P > 0.5). The mutation spectrum of the LY171883 lesions was not significantly different from the spontaneous spectra. It may be concluded that based on the similarity in mutation spectrum and the increase in mutation frequency, LY171883 may selectively promote spontaneous hepatic lesions containing H-ras 61st codon mutations. In addition, the difference in mutation frequency among lesion types does not support a linear progression of all LY171883 lesions through focal atypia, focal hepatocellular hyperplasias, hepatocellular adenomas and hepatocellular carcinomas.  相似文献   
2.
Exposure to adverse life events typically predicts subsequent negative effects on mental health and well-being, such that more adversity predicts worse outcomes. However, adverse experiences may also foster subsequent resilience, with resulting advantages for mental health and well-being. In a multiyear longitudinal study of a national sample, people with a history of some lifetime adversity reported better mental health and well-being outcomes than not only people with a high history of adversity but also than people with no history of adversity. Specifically, U-shaped quadratic relationships indicated that a history of some but nonzero lifetime adversity predicted relatively lower global distress, lower self-rated functional impairment, fewer posttraumatic stress symptoms, and higher life satisfaction over time. Furthermore, people with some prior lifetime adversity were the least affected by recent adverse events. These results suggest that, in moderation, whatever does not kill us may indeed make us stronger. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
3.
This paper gives a class of flow control algorithms for the adaptive allocation of bandwidths to virtual connections (VC) in high-speed, wide-area ATM networks. The feedback rate to the source from the network is parsimonious, with each feedback bit indicating whether the buffer at a distant switch is above or below a threshold. The service discipline at the switch is first-come-first-served. The important goal of adaptability aims to make all of the network bandwidth available to the active VCs, even though the number of such VCs is variable over a given range. Each VC has two parameters, one giving its minimum guaranteed bandwidth and the other is the weight for determining its share of the uncommitted bandwidth. Judicious selection of these parameters defines distinctive services, such as best effort and best effort with minimum bandwidth. We derive design rules for selecting the parameters of the algorithms such that the appropriate guarantees and fairness properties are exhibited in the dynamical behavior. The systematic use of “damping” in right proportion with “gain” is shown to be a powerful device for stabilizing behavior and achieving fairness. Our analyses are based on a simple analytic fluid model composed of a system of first-order delay-differential equations, which reflect the propagation delay across the network. Extensive simulations examine the following: (1) fairness, especially to start-up VCs; (2) oscillations; (3) transient behavior, such as the rate of equalization from different initial conditions; (4) disparate bandwidth allocations; (5) multiple paths with diverse propagation delays; (6) adaptability and robustness with respect to parameters; and (7) interoperability of different algorithms  相似文献   
4.
The association of panniculitis and pancreatitis is well described. However, panniculitis remains a relatively uncommon manifestation of pancreatic inflammation. We report a case in which treatment of pancreatitis by the placement of a pancreatic stent led to simultaneous resolution of both the pancreatitis and the associated panniculitis. There are no other reports in the literature demonstrating resolution of panniculitis subsequent to stent placement or definitive surgery.  相似文献   
5.
Results of Gamma nail use in treatment for trochanteric fracture of the femur in 25 patients (15 females, 10 males) aged 45-91 years are presented. There were 12 type I, 9 type II, 3 type III and 1 type IV fracture according to Boyd-Griffin classification. Fracture healed 10-12 weeks after surgery in 24 cases; one patient died because of pulmonary embolism.  相似文献   
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7.
We report studies of the effect of counterions on the properties of solutions of a strong polyelectrolyte for a wide range of solvent dielectric constant. For this purpose we investigated the dynamic properties of polystyrene sulfonate in N‐methylformamide whose dielectric constant changes significantly with temperature. By means of dynamic light scattering and NMR spectroscopy, polymers of different molecular weights and various counterions were investigated, including large phosphazene counterions P1, P2 and P4 measured for the first time. It was found that the order of counterion binding of ionomers in the solvent changed with an increase of dielectric constant. The order for low dielectric constant (high temperature) was Na < Rb < Cs < P1 < P2 < P4, whereas for a solvent with high dielectric constant no influence of counterion nature was observed. The solvation–desolvation effect together with electrostatic interactions are responsible for the observed phenomenon. © 2012 Society of Chemical Industry  相似文献   
8.
Collective traumas can negatively affect large numbers of people who ostensibly did not experience events directly, making it particularly important to identify which people are most vulnerable to developing mental and physical health problems as a result of such events. It is commonly believed that successful coping with a traumatic event requires expressing one's thoughts and feelings about the experience, suggesting that people who choose not to do so would be at high risk for poor adjustment. To test this idea in the context of collective trauma, 2,138 members of a nationally representative Web-enabled survey panel were given the opportunity to express their reactions to the terrorist attacks of September 11, 2001, on that day and those following. Follow-up surveys assessing mental and physical health outcomes were completed over the next 2 years. Contrary to common belief, participants who chose not to express any initial reaction reported better outcomes over time than did those who expressed an initial reaction. Among those who chose to express their immediate reactions, longer responses predicted worse outcomes over time. Implications for myths of coping, posttrauma interventions, and psychology in the media are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
Three studies examined cardiovascular (CV) responses during emotional expression with empathically responsive strangers. Study 1 demonstrated that self-relevant emotional expression fostered CV reactivity consistent with challenge. Study 2 manipulated content of discussion by assigning participants to 1 of 4 conditions: emotional, nonemotional, emotional suppression, nonemotional suppression. In same-sex dyads, emotional suppression elicited CV challenge reactivity whereas emotional suppression evoked CV threat reactivity, both compared with appropriate control groups. In opposite-sex dyads, however, emotional expression engendered CV threat. Because same- and opposite-sex disclosures differed, Study 3 controlled the content of emotional expression while manipulating gender context. Results confirmed findings from the first 2 studies, indicating that both context and content of emotional expression influenced CV effects. Findings are discussed within a theoretical challenge and threat perspective. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
10.
pC194-type plasmids have been isolated from widely divergent species of bacteria: Gram positive, Proteobacteria, Spirochaetes and Cyanobacteria. We have examined the three essential replication elements of these plasmids, i.e., the Rep protein, and the origins of double and single stranded synthesis. Comparative analysis of Rep protein sequences from these plasmids indicates that they are highly divergent. Those isolated from Gram positive species fall into five groups: a Bacillus group, a Lactobacillus group, a Streptococcus group and two Staphylococcus aureus groups. The two S. aureus clusters are quite separate, suggesting that there has been at least one plasmid transfer between divergent Gram positive species. The double stranded origin of replication and the active site of the Rep protein display similarities across species indicating that these motifs can function in very divergent hosts. In contrast the single stranded origin of replication is typical of the host from which the plasmid is isolated. This is exemplified by (i) pKYM where the single stranded origins are similar to the minus origins found on the single-stranded coliphages, and (ii) pTD1 (isolated from a Spirochaete), pNostoc, pMA1 and pRF1 (all isolated from Cyanobacteria) which have no sequence homology to the minus origins identified in Gram positive or Gram negative species. This points to the single stranded origin as a feature critical to the determination of the host range of the plasmid.  相似文献   
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