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31.
We used multidimensional scaling to model the semantic network of alcohol and marijuana expectancies (N = 897). Preference mapping was used to estimate vectors representing patterns of activation through the network as a function of levels of behavioral inhibition (BIS) and behavioral activation (BAS). Individuals with low BIS combined with high BAS levels exhibited patterns of activation emphasizing behavioral activation similar to heavier drug users in previous research. High BIS, low BAS individuals exhibited activation patterns with greater emphasis on inhibitory expectancies similar to low-level users. Differences in expectancy activation patterns were maintained after controlling for substance use and gender. Individual differences in BIS/BAS are associated with the organization of semantic networks and patterns of activation of expectancies contributing to differences in substance use behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
32.
The majority of equations used to predict values for basal metabolic rates (BMRs) are the result of indirect calorimetry measurements performed in the 1930s and 1950s. To assess the reliability of these equations in predicting the resting energy expenditure (REE) of the children in our community, indirect calorimetry was performed on 92 male and 107 female healthy children 2-3 h postprandial. Each individual was measured for a duration of 15-20 min. The data for analysis were obtained from 5-15 min steady-state periods. Subjects ranged in age from 5 to 16 years. The results were compared with BMRs calculated from the Harris-Benedict equation (Harris J, Benedict F. A biometric study of basal metabolism in man. Washington, DC: Carnegie Institute of Washington, publication no. 279, 1919.), the Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU) equations, and the equations proposed by Schofield for use by the 1985 FAO/WHO/UNU Nutrition Committee. The values predicted by the FAO/WHO/UNU and Schofield equations were consistent with the measured resting values for all the children in the study population. Ninety-two children weighed between 90-110% of their ideal body weight. When the measured REE and estimated BMR were compared by gender and age in these children, the Schofield equations provided the best estimates. Ninety-four of the study subjects weighed > 110% of their ideal body weight. The predicted estimates by all equations were consistent with the measured values in this subgroup of the population. We conclude that the FAO/WHO/UNU and Schofield equations are reliable estimates of metabolic rate in healthy children when measurement of REE is not possible.  相似文献   
33.
Initiating events leading to the accumulation of malignant ascites in the peritoneal cavity were investigated in two syngeneic transplantable murine ascites-producing tumors, MOT mouse ovarian tumor and the TA3/St mammary carcinoma. The transport of two tracers, 125I-labeled human serum albumin (125I-HSA) and 51Cr-labeled red blood cells (51Cr-RBC), into and out of the peritoneal cavity was studied at early times after i.p. tumor cell injection, prior to abundant fluid accumulation, and at intervals of 5 to 360 min after i.v. or i.p. tracer injection. Tracer influx and efflux rates were estimated from the mass of tracer passing into or out of the peritoneal cavity following a bolus injection of tracer into either the blood or the peritoneal cavity. Efflux of 125I-HSA from the peritoneal cavity was markedly reduced (3- to 5-fold) within 1 day of i.p. injection of either type of tumor cell. Significantly reduced efflux preceded any increase in tumor cell number and by itself did not induce peritoneal fluid accumulation. 125I-HSA tracer influx from plasma to peritoneal fluid did not increase detectably until 5 to 7 days after tumor cell injection, when the tumor cell number had increased by 10- to 100-fold. Only at relatively late stages of ascites tumor growth, when the flow rate into the peritoneal cavity had increased relative to the flow rate out of the peritoneum, was there net peritoneal fluid accumulation. Thus, increased influx, in addition to impaired efflux, were required for malignant ascites accumulation. Following i.p. injection, the efflux rates of 125I-HSA always exceeded those of 51Cr-RBC, even in ascites tumor-bearing animals. Furthermore, 125I-HSA tracer disappeared from the peritoneal cavity more rapidly than it appeared in the plasma, suggesting that 125I-HSA moves more rapidly through the channels by which 51Cr-RBC egress from the peritoneum (primarily diaphragmatic lymphatics) and/or has access to additional pathways not open to 51Cr-RBC. Finally, flow rates into and out of the blood and peritoneum were used to obtain kinetic parameters that characterized tracer transport: k1, the rate constant for tracer transport from the blood to the peritoneum; k2, the rate constant for tracer transport from the peritoneal cavity to the blood; and k6, the rate constant for tracer transport from the peritoneal cavity to surrounding interstitial tissue.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
34.
A framework is described that was developed to help assess communications service quality in a manner that most closely reflects the broad array of performance parameters experienced by customers. Examples of its application are presented. An additional benefit experienced with the use of this framework is a more consistent, disciplined analysis of service parameters, adding to the thoroughness with which service providers and customers alike assess the quality of communications services  相似文献   
35.
In terms of climate, the Czech Republic belongs to the northern hemisphere Atlantic-contin ental type of moderate clim ate. M ean annual temperature ranges between 1.0 and 9.4 C (for summer between 8.8 C and 18.5 C, and for winter between - 6.8 and 0.2 C). Annual precipitation ranges between 450 mm in dry regions and 1300 m m in mountainous regions of the country. With its 2000 m 3 per capita fresh water availability, the Czech Republic is a region that can be characterized as slightly below average in availability. The occasional water shortages usually do n ot result from unavailability of water, but rather from temporal or spatial variability of water supply and demand and a high degree of water resources exploitation. To study poten tial im pacts of climate change on the hydrological system and water resources, four river basins have been selected in the territory of the Czech Republic: the Elbe River at De c i n (50762 km 2), the Zelivka River at Soutice (1189 km 2), the Upa River at Ceska Skalice (461 km 2), and the M etuje River at M ars ov n. M . (94 km 2). To simulate poten tial changes in runoff, three hydrological models have been applied using in cremental and GCM (GISS, GFDL and CCCM ) scenarios: the BILAN water balance model, the SACRAM ENTO (SAC-SM A) conceptual model and the CLIRU N water balance m odel. After comparison of the results, the BILAN m odel was selected to serve for subsequent analyses of hydrological systems in the river basins. The paper reviews methods applied in the study and results of the assessments, and it concludes with suggestions for general adaptation policy options where the preference is for non-structural measures such as water conservation, efficient water dem and management and protection of water resources.  相似文献   
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The design, construction and operation of a computer-compatible system to measure and record optical retardation with a polarizing or interference microscope is described. The system consists of a high precision potentiometer linked directly to the drum vernier of a compensator or analyser. A highly stabilized fixed voltage is applied to the potentiometer and the voltage difference between the potentiometer wiper and one end of the resistance element is directly proportional to the compensator or analyser angle. This voltage is converted to a digital format, interfaced with a digital time base and stored on punched paper tape for subsequent computer analysis.  相似文献   
39.
R++: adding path-based rules to C++   总被引:1,自引:0,他引:1  
Object-oriented languages and rule-based languages offer two distinct and useful programming abstractions. However, previous attempts to integrate data-driven rules into object-oriented languages have typically achieved an uneasy union at best. R++ is a new, closer integration of the rule-based and object-oriented paradigms that extends C++ with a single programming construct, the path-based rule, as a new kind of class member. Path-based rules-data-driven rules that are restricted to following pointers between objects-are like automatic methods that are triggered by changes to the objects they monitor. Path-based rules provide a useful level of abstraction that encourages a more declarative style of programming and are valuable in object-oriented designs as a means of modeling dynamic collections of interdependent objects. Unlike more traditional pattern-matching rules, path-based rules are not at odds with the object-oriented paradigm and offer performance advantages for many natural applications  相似文献   
40.
The entire fluorescence decay profile during HPLC elution has been directly measured on-the-fly in HPLC at higher sensitivity than in previous literature reports. The fluorescence is excited with the fourth harmonic (266 nm) of a pulsed Nd:YAG laser system and detected broadband with a photomultiplier tube and a digital storage oscilloscope. Detection limits in the range 1-10 ppb are found for several individual polycyclic aromatic hydrocarbons (PAHs) when the total time-integrated fluorescence is analyzed. The chromatograms of PAH mixtures containing 8-10 species were lifetime analyzed with a simple phase plane analysis, in which a single lifetime is determined from the fluorescence decay profile for each point on the chromatogram. The determination of lifetimes under coelution conditions is also illustrated and discussed.  相似文献   
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