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991.
1. The effects of propofol (2,6 di-isopropylphenol) on responses to the selective glutamate receptor agonists, N-methyl-D-aspartate (NMDA) and kainate, were investigated in cultured hippocampal neurones of the mouse. Whole cell and single channel currents were recorded by patch-clamp techniques. Drugs were applied with a multi-barrel perfusion system. 2. Propofol produced a reversible, dose-dependent inhibition of whole cell currents activated by NMDA. The concentration of propofol which induced 50% of the maximal inhibition (IC50) was approximately 160 microM. The maximal inhibition was incomplete leaving a residual current of about 33% of the control response. This inhibitory action of propofol was neither voltage- nor use-dependent. 3. Analysis of the dose-response relation for whole cell NMDA-activated currents indicated that propofol caused no significant change in the apparent affinity of the receptor for NMDA. 4. Outside-out patch recordings of single channel currents evoked by NMDA (10 microM) revealed that propofol (100 microM) reversibly decreased the probability of channel opening but did not influence the average duration of channel opening or single channel conductance. 5. Whole-cell currents evoked by kainate (50 microM) were insensitive to propofol (1 microM-1 mM). 6. These results indicate that propofol inhibits the NMDA subtype of glutamate receptor, possibly through an allosteric modulation of channel gating rather than by blocking the open channel. Depression of NMDA-mediated excitatory neurotransmission may contribute to the anaesthetic, amnesic and anti-convulsant properties of propofol. 相似文献
992.
BACKGROUND: The aim of our study was to evaluate the prevalence of thyroid abnormalities among depressed outpatients and to examine the response to treatment of those subjects with relatively low or high thyroid hormone levels. METHOD: Outpatients (N = 200) 18 to 65 years of age who met DSM-III-R criteria for major depression were screened for the presence of thyroid abnormalities using a number of thyroid indices. Of these patients, 166 were then treated openly with the antidepressant fluoxetine for 12 weeks. We assessed whether patients with relatively low or high thyroid hormone levels had a different response to treatment compared with other patients. The 17-item Hamilton Rating Scale for Depression (HAM-D-17) was administered during the study to assess changes in depressive symptoms. Thyroid function was assessed by measuring T3, T4, free T4 index (FT4I), T3 uptake (T3U), and serum thyroid-stimulating hormone (TSH) levels. RESULTS: No clinical cases of hyperthyroidism or hypothyroidism were detected. Of the patients examined, 5 (2.6%) had slightly elevated TSH levels (range, 4.7-8.2); none of these had T4 or FT4I levels below the normal range. Subnormal levels of T4 or FT4I were found in 1 subject (0.5%). T3 and T3U levels were below the normal range in a larger number of patients (7.6% and 15.0% respectively), but only 1 of these patients had elevated TSH levels. None of the patients had levels of TSH below the normal range, and only 3 subjects (1.5%) had T4 levels above the normal range. No relationship was found between response rate (assessed as either change in HAM-D-17 score or as remission of depressive symptoms with a HAM-D-17 score < or = 7 for 3 consecutive weeks) and each of the thyroid tests, even after adjusting for baseline severity of depression. CONCLUSION: In depressed outpatients, it appears that hypothyroidism and hyperthyroidism are extremely uncommon and that the presence of subtle thyroid function abnormalities does not have an impact on treatment outcome. 相似文献
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996.
Primary oral squamous cell carcinoma: a review of 92 cases 总被引:1,自引:0,他引:1
PURPOSE: This is a retrospective review of 92 cases of oral squamous cell carcinoma treated by one department of oral and maxillofacial surgery. PATIENTS AND METHODS: The medical records of 92 patients with oral squamous cell carcinoma were reviewed, and standard epidemiologic data were obtained. In addition, cases were identified as to site, stage, risk behavior, histologic classification, primary and secondary surgical treatment, adjunctive therapy, and survival rates. RESULTS: The results indicate a higher-than-predicted 2-year survival rate. The association between alcohol and tobacco consumption and incidence of disease is supported. There was a correlation between tumor size and survival rate, but no correlation between histologic classification and prognosis. CONCLUSION: Mortality increases in relation to the stage at which the diagnosis of oral squamous cell carcinoma is made. Patients with stage III or IV lesions have a much poorer prognosis than those with stage I or II lesions. However, histologic classification and prognosis were not correlated. 相似文献
997.
WE Johnston PG Robertie JF Butterworth RL Royster ND Kon 《Canadian Metallurgical Quarterly》1992,6(5):528-534
To determine whether ephedrine or CaCl2 improves hemodynamics in cardiac surgery patients emerging from cardiopulmonary bypass, three sequential doses of either CaCl2 (200 mg/dose; n = 12), ephedrine (5 mg/dose; n = 12), or placebo (n = 12) were administered in a prospective, randomized, double-blind fashion. Thermodilution volumetric catheters were used to calculate right ventricular (RV) volumes and ejection fraction. The first dose of ephedrine improved RV stroke volume from 57 +/- 3 to 63 +/- 4 mL/beat (P < 0.05) and ejection fraction from 44 +/- 2% to 49 +/- 2% (P < 0.05). Subsequent doses maintained this improvement but without further change. In contrast, placebo and CaCl2 had minimal effects on RV end-systolic volume, stroke volume, and ejection fraction. After the third injection of ephedrine, mean arterial pressure had significantly increased from 78 +/- 2 to 93 +/- 4 mmHg (P < 0.05) in contrast to insignificant increments with placebo and CaCl2. Serum ionized calcium increased by 6% to 8% after each CaCl2 bolus but remained stable in the ephedrine and placebo groups. CaCl2 failed to improve RV performance in mildly hypocalcemic patients during separation from cardiopulmonary bypass. In patients with normal preoperative ventricular function, ephedrine more effectively improved RV performance and arterial blood pressure than placebo or CaCl2, and is a suitable short-acting drug to assist separation from cardiopulmonary bypass. 相似文献
998.
Occupational stress is a cause of considerable morbidity, but research on work stressors has comparatively neglected the moderating effects of gender, age, ethnicity, and occupation. A workforce of 5,467 European, Maori, Pacific Islander, and Asian employees, 40 years old or older, working for 41 companies, completed a questionnaire giving details of total stressors and subcategories of stressors. Relative risks were estimated using numbers above and below median scores. There were significant associations between increased stressors and the following [with category showing highest relative risk, and corresponding relative risk (95% confidence interval)]: male gender [job scope, 1.50(1.37,1.63)]; young age [rapport with management, 1.34(11.23,1.46)]; administrative goup [job pressure, 1.85(1.69,2.03)]; and a negative association with Pacific Islander ethnicity [rapport with management, 0.59(0.52,0.66)]. These findings indicate areas in a workforce to which stress-reduction interventions can be directed. 相似文献
999.
Although conventional MR imaging allows direct visualization of major anatomic structures, smaller intraarticular structures, including the glenoid labrum, glenohumeral ligaments, and articular surface of the rotator cuff tendon can be difficult to evaluate in the absence of a joint effusion. The authors review the techniques employed in performing MR arthrography, imaging characteristics of MR arthrography, and diagnostic utilization of the technique. Suggested indications are provided. 相似文献
1000.
Mammalian mastication is a process combining simultaneous food comminution and lubrication. The initiation of swallowing, which is voluntary, has been thought to depend on separate thresholds for food particle size and for particle lubrication. Instead of this duality, we suggest that swallowing is initiated when it is sensed that a batch of food particles is binding together under viscous forces so as to form a bolus. Bolus formation ensures that when the food mass is swallowed, it will pass the pharyngeal region safely without risk of inhaling small particles into the lower respiratory tract. Crucial for bolus formation is food particle size reduction by mastication. This allows the tongue to pack particles together tightly by pressure against the hard palate. A major function of salivation is to fill the gradually reducing spaces between particles, so increasing viscous cohesion and promoting bolus formation. If swallowing is delayed, excessive saliva floods the bolus, separating particles and reducing cohesion. Swallowing then becomes more precarious. Our model suggests that there is an optimum moment for a mammal to swallow, defined in terms of a peak cohesive force between food particles. The model is tested on human mastication with two foods, brazil nut and raw carrot, which have very different particle size breakdown rates. The peak cohesive force is much greater with brazil nuts but both foods are predicted to be swallowed after similar numbers of chews despite the very different food particle size reductions achieved at that stage. The predicted number of chews to swallow is in broad agreement with published data. 相似文献