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21.
The experimental results from the various reaction and radioactive decay studies leading to nuclides in the A-161 mass chain have been reviewed. These data are summarized and presented, together with adopted level schemes and properties.  相似文献   
22.
3D printing has emerged as an enabling technology for miniaturization. High‐precision printing techniques such as stereolithography are capable of printing microreactors and lab‐on‐a‐chip devices for efficient parallelization of biological and biochemical reactions under reduced uptake of reactants. In the world of chemistry, however, up until now, miniaturization has played a minor role. The chemical and thermal stability of regular 3D printing resins is insufficient for sustaining the harsh conditions of chemical reactions. Novel material formulations that produce highly stable 3D‐printed chips are highly sought for bringing chemistry up‐to‐date on the development of miniaturization. In this work, a brief review of recent developments in highly stable materials for 3D printing is given. This work focuses on three highly stable 3D‐printable material systems: transparent silicate glasses, ceramics, and fluorinated polymers. It is further demonstrated that 3D printing is also a versatile technique for surface structuring of polymers to enhance their wetting performance. Such micro/nanostructuring is key to selectively wetting surface patterns that are versatile for chemical arrays and droplet synthesis.  相似文献   
23.
A spatially explicit dataset of aboveground live forest biomass was made from ground measured inventory plots for the conterminous U.S., Alaska and Puerto Rico. The plot data are from the USDA Forest Service Forest Inventory and Analysis (FIA) program. To scale these plot data to maps, we developed models relating field-measured response variables to plot attributes serving as the predictor variables. The plot attributes came from intersecting plot coordinates with geospatial datasets. Consequently, these models serve as mapping models. The geospatial predictor variables included Moderate Resolution Imaging Spectrometer (MODIS)-derived image composites and percent tree cover; land cover proportions and other data from the National Land Cover Dataset (NLCD); topographic variables; monthly and annual climate parameters; and other ancillary variables. We segmented the mapping models for the U.S. into 65 ecologically similar mapping zones, plus Alaska and Puerto Rico. First, we developed a forest mask by modeling the forest vs. nonforest assignment of field plots as functions of the predictor layers using classification trees in See5©. Secondly, forest biomass models were built within the predicted forest areas using tree-based algorithms in Cubist©. To validate the models, we compared field-measured with model-predicted forest/nonforest classification and biomass from an independent test set, randomly selected from available plot data for each mapping zone. The estimated proportion of correctly classified pixels for the forest mask ranged from 0.79 in Puerto Rico to 0.94 in Alaska. For biomass, model correlation coefficients ranged from a high of 0.73 in the Pacific Northwest, to a low of 0.31 in the Southern region. There was a tendency in all regions for these models to over-predict areas of small biomass and under-predict areas of large biomass, not capturing the full range in variability. Map-based estimates of forest area and forest biomass compared well with traditional plot-based estimates for individual states and for four scales of spatial aggregation. Variable importance analyses revealed that MODIS-derived information could contribute more predictive power than other classes of information when used in isolation. However, the true contribution of each variable is confounded by high correlations. Consequently, excluding any one class of variables resulted in only small effects on overall map accuracy. An estimate of total C pools in live forest biomass of U.S. forests, derived from the nationwide biomass map, also compared well with previously published estimates.  相似文献   
24.
An automated beam transport system that improves the operation of an industrial radioisotope production facility by incorporating features that enhance both the reliability of operation and the ease of maintenance in a radiation environment is described. The theoretical and practical aspects of the optical design, the diagnostic and protection equipment, the vacuum components, and the control and operation of the beamline are covered. Future work is discussed, and conclusions are given  相似文献   
25.
Selective serotonin reuptake inhibitors (SSRIs) are the 'new' drugs of first choice for the treatment of depression in the older patient. Systematic studies on the effects of SSRIs on cardiac function are scarce, despite the high prevalence of cardiac disorders in the older depressed patient. This is a study which systematically assessed cardiac function by echocardiography in middle-aged and elderly depressed patients treated with SSRI. In a double-blind randomized trial, 20 patients were assigned to receive fluvoxamine 100 mg/day [DOSAGE ERROR CORRECTED] or fluoxetine 20 mg/day [DOSAGE ERROR CORRECTED] for 6 weeks. Cardiac function was assessed by left ventricle ejection fraction, aortic flow integral and early or passive/late or active mitral inflow, and electrocardiography. Neither SSRI significantly affected cardiac function. Compared with patients without a history of myocardial infarction and/or hypertension, patients with such a history showed a significant improvement in left ventricular ejection fraction. Despite our small study sample, these data indicate that both fluoxetine and fluvoxamine do not affect cardiac function adversely.  相似文献   
26.
Patients with essential thrombocythaemia (ET) exhibit a decrease of large von Willebrand factor (VWF) multimers in plasma, which is inversely related to the platelet count. In the present study we investigated whether the decrease of large VWF multimers in plasma with increasing platelet counts is the consequence of increased turnover of large VWF multimers in vivo. To that end we measured the half-life times of endogenously released VWF:Ag and VWF:CBA (collagen binding activity) after intravenous administration of desmopressin (DDAVP) to nine ET patients and nine control subjects (N). In addition, the half-life times of VWF:Ag and VWF:CBA were also measured in four ET patients after cytoreduction of the increased platelet count to normal or nearly normal values. Estimated half-life times of VWF:Ag did not differ between ET patients and normals (11.0+/-4.0 h v 12.4+/-2.5 h, P>0.05). Estimated half-life times of VWF:CBA were significantly lower in ET patients as compared with normal individuals (6.1+/-2.0 h v 8.4+/-2.5 h, P<0.05). After cytoreduction of the increased platelet count to (nearly) normal values in all four ET patients the half-life time of VWF:CBA significantly (P=0.014) increased from 5.2+/-1.2 h to 8.7+/-2.0 h. Our data suggest that platelets may play a role in the homeostasis of circulating von Willebrand factor, which may compromise normal haemostasis at fairly increased platelet counts.  相似文献   
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28.
Two boys with presumably congenital cystic changes in the lungs are described. In one child multiple cystic deformations led to acute symptoms of severe respiratory distress necessitating urgent resection of the right middle and upper lobes. The other boy had a large thick-walled cyst in the left upper lobe causing no distress whatsoever. This patient was observed for more than 6 years before operation. Multiple vascular anomalies and anastomoses were revealed during surgery. Both cases are presented in detail and the completely different clinical course is outlined. Only when careful supervision of intrapulmonary cystic changes is guaranteed can operation be postponed for longer than 6 months. Pulmonary cysts may lead to emergency procedures. They are always a potential source of serious complications such as rupture or infection. When no tendency for regression can be discovered surgical removal is indicated. Conservative treatment will not influence the course. Differential diagnosis is discussed briefly.  相似文献   
29.
The author describes a case of intracerebral and subarachnoid hemorrhage associated with an intracranial aneurysm caused by a metastatic tumor. The aneurysm formation is explained as being result of tumor cells invading the vessel wall while still preserving the arterial circulation.  相似文献   
30.
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