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1.
Optimum diversity and worst-case partial-band noise jamming conditions have been derived for noncoherent energy detection of frequency-hopped (FH)M -ary frequency-shift keyed (MFSK) signals using a soft-chip decision suboptimum linear combining metric with perfect jamming-state side information. However, the assumption implicit in previous publications is that the error rate is first maximized over the jammer's partial-band duty factor for arbitrary diversity, and the result is then minimized over the amount of diversity. This paper shows that if the order of optimization is reversed, different conditions and performance are produced; that is, the previous solution is not a saddlepoint. This introduces some game-theoretic considerations for the communicator and the jammer, the risks and advantages of which are explored. 相似文献
2.
Levitt Mary J.; Guacci-Franco Nathalie; Levitt Jerome L. 《Canadian Metallurgical Quarterly》1993,29(5):811
Little is known about social networks in childhood, and even less is known about the networks of ethnically diverse children. Interviews were conducted with 333 African-American, Anglo/European-American, and Hispanic-American public school children in Grades 1–2, 4–5, and 8–9. The research was based on the social convoy model (R. L. Kahn and T. C. Antonucci, 1980), in which social networks are viewed as dynamic hierarchic structures affording the provision of support across the life span. An adapted convoy mapping procedure evidenced good test–retest reliability at all ages, and convoy support measures were associated with self-concept and teacher-rated sociability and mood. For all ethnic groups, the results reflect the significance of close family relations across age, an increase in involvement with extended family in middle-childhood, and the emergent role of peers as support providers in adolescence. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
CG Tankersley RS Fitzgerald RC Levitt WA Mitzner SL Ewart SR Kleeberger 《Canadian Metallurgical Quarterly》1997,82(3):874-881
The purpose of the present study was to determine the genetic control of baseline breathing pattern by examining the mode of inheritance between two inbred murine strains with differential breathing characteristics. Specifically, the rapid, shallow phenotype of the C57BL/6J (B6) strain is consistently distinct from the slow, deep phenotype of the C3H/HeJ (C3) strain. The response distributions of segregant and nonsegregant progeny were compared with the two progenitor strains to determine the mode of inheritance for each ventilatory characteristic. The BXH recombinant inbred (RI) strains derived from the B6 and C3 progenitors were examined to establish strain distribution patterns for each ventilatory trait. To establish the mode of inheritance, baseline breathing frequency (f), tidal volume, and inspiratory time (TI) were measured five times in each of 178 mature male animals from the two progenitor strains and their progeny by using whole body plethysmography. With respect to f and TI, the two progenitor strains were consistently distinct, and segregation analyses of the inheritance pattern suggest that the most parsimonious genetic model for response distributions of f and TI is a two-loci model. In similar experiments conducted on 82 mature male animals from 12 BXH RI strains, each parental phenotype was represented by one or more of the RI strains. Intermediate phenotypes emerged to confirm the likelihood that parental strain differences in f and TI were determined by more than one locus. Taken together, these studies suggest that the phenotypic difference in baseline respiratory timing between male B6 and C3 mice is best explained by a genetic model that considers at least two loci as major determinants. 相似文献
4.
MXene Yarn Supercapacitors: High‐Performance Biscrolled MXene/Carbon Nanotube Yarn Supercapacitors (Small 37/2018) 下载免费PDF全文
5.
The author discussed the increase in the frequency of traumatic paralyses of the ocular muscles, and reported 6 cases of inferior oblique muscle paresis caused by local blunt or sharp traumas (haematoma, contusion, rupture, incarceration) and one case of traumatic Brownian pseudo-paralysis. The localisation of the injuries in 3 cases was on the inferior temporal part and in the other 3 cases on the superior part of the bulbar conjunctiva. Atypical horizontal deviation and characteristic vertical deviation, torsion and torticollis were observed in the majority of cases. One patient recovered spontaneously. 3 patients became asymptomatic after correction by prisms and one after recession of contralateral superior rectus muscle. The symptoms remained unchanged in the case of a "blow out" fracture (in spite of operation) and a Brown's syndrome (without treatment). 相似文献
6.
A. Abrizah Mohammadamin Erfanmanesh Vala Ali Rohani Mike Thelwall Jonathan M. Levitt Fereshteh Didegah 《Scientometrics》2014,101(1):569-585
This paper analyses the information science research field of informetrics to identify publication strategies that have been important for its successful researchers. The study uses a micro-analysis of informetrics researchers from 5,417 informetrics papers published in 7 core informetrics journals during 1948–2012. The most productive informetrics researchers were analysed in terms of productivity, citation impact, and co-authorship. The 30 most productive informetrics researchers of all time span several generations and seem to be usually the primary authors of their research, highly collaborative, affiliated with one institution at a time, and often affiliated with a few core European centres. Their research usually has a high total citation impact but not the highest citation impact per paper. Perhaps surprisingly, the US does not seem to be good at producing highly productive researchers but is successful at producing high impact researchers. Although there are exceptions to all of the patterns found, researchers wishing to have the best chance of being part of the next generation of highly productive informetricians may wish to emulate some of these characteristics. 相似文献
7.
Alfred S. Levitt 《Journal of the American Planning Association. American Planning Association》2013,79(2):80-81
Planning initiative on the part of individual groups and communities within urban areas has been made necessary by the increasing bureaucratization and technical basis of decisions in current urban society. The efforts of advocate planners to represent these groups are made difficult because of their frequent lack of homogeneity, community feeling, and common interests in action. The treatment of local areas as “communities” of homogeneous interests can result in severe damage to the interest of their weakest inhabitants. Further, it is difficult to draw low-income families into the framework of planning, and to evoke their concern for the planning issues normally posed by the local establishment. Thus it is necessary to carefully generate viable issues in the work and maintain a consciousness of the interrelation of technical and political matters at all levels. The advocate planner's need to evoke and formulate issues maizes him dangerously similar to other manipulators of the poor's interests. One of the most difficult kinds of issues is the type like transportation which, although generated at the community level, must be studied and argued at the metropolitan scale with the consequent loss of a clearly identified client group. Advocacy planning takes many forms depending on its sponsorship. In spite of its problems, it fills a crucial need for managing latent conflict in the cities and for humanizing public action. 相似文献
8.
T.E. Derry E.K. Nshingabigwi M. Levitt S.R. Naidoo 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(16):2705-2707
It has formerly been shown that low-damage levels, produced during the implantation doping of diamond as a semiconductor, anneal easily while high levels “graphitize” (above about 5.2 × 1015 ions/cm2). The difference in the defect types and their profiles, in the two cases, has never been directly observed. We have succeeded in using cross-section transmission electron microscopy to do so. The experiments were difficult because the specimens must be polished to ∼40 μm thickness, then implanted on edge and annealed, before final ion beam thinning to electron transparency. The low-damage micrographs reveal some deeply penetrating dislocations, whose existence had been predicted in earlier work. 相似文献
9.
10.
The relationship between blood ethanol concentration and hepatic ethanol metabolism commonly is calculated using the Michaelis-Menten equation and a one-compartment model that assumes equality of blood and hepatic ethanol concentrations. However, at low blood concentrations, most of the ethanol arriving at the liver is metabolized, and hepatic ethanol concentrations may fall far below that of the entering blood. We have developed a two-compartment model of ethanol metabolism that accounts for the fall in ethanol concentration that may occur as blood traverses the liver and used this model to make predictions concerning ethanol metabolism at various blood ethanol concentrations. The two-compartment model predicts that near-complete saturation will occur more abruptly and at a lower blood concentration (approximately 3 mM) than is the case with the one-compartment model. Thus, the two-compartment model predicts a near-constant ethanol elimination rate for blood ethanol concentrations above 3 mM (as commonly observed in human subjects), whereas the one-compartment model predicts an increasing elimination rate over the range of concentrations observed in experimental studies. In agreement with observed data, the two-compartment model predicts that first-pass metabolism should be extremely sensitive to the rate of ethanol absorption. Application of this model to previously published data indicated that, when absorption was slowed via concomitant food ingestion, first-pass metabolism accounts for approximately 50% and 10% of ethanol dosages of 0.15 g/kg and 0.3 g/kg, respectively. When ingested without food, there is negligible first-pass metabolism of even very small ethanol dosages (0.15 g/kg). These findings suggest that first-pass metabolism is an unimportant determinant of the blood ethanol response to ingestion of potentially inebriating doses of ethanol. 相似文献