全文获取类型
收费全文 | 294篇 |
免费 | 16篇 |
专业分类
电工技术 | 1篇 |
综合类 | 1篇 |
化学工业 | 68篇 |
金属工艺 | 3篇 |
机械仪表 | 3篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 3篇 |
轻工业 | 23篇 |
水利工程 | 1篇 |
无线电 | 34篇 |
一般工业技术 | 31篇 |
冶金工业 | 91篇 |
原子能技术 | 6篇 |
自动化技术 | 34篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 10篇 |
2013年 | 14篇 |
2012年 | 13篇 |
2011年 | 14篇 |
2010年 | 11篇 |
2009年 | 10篇 |
2008年 | 14篇 |
2007年 | 10篇 |
2006年 | 12篇 |
2005年 | 11篇 |
2004年 | 13篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 31篇 |
1997年 | 20篇 |
1996年 | 11篇 |
1995年 | 2篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有310条查询结果,搜索用时 562 毫秒
31.
SB D'Avanzo T Graziano DE Metz N Schiavetti RL Whitehead 《Canadian Metallurgical Quarterly》1998,31(4):337-45; quiz 345-6
Simultaneous communications combines both spoken and manual modes to produce each word of an utterance. This study investigated the potential influence of alterations in the temporal structure of speech produced by inexperienced signers during simultaneous communication on the perception of final consonant voicing. Inexperienced signers recorded words that differed only in the voicing characteristic of the final consonant under two conditions: (1) speech alone and (2) simultaneous communication. The words were subsequently digitally edited to remove the final consonant and played to 20 listeners who, in a forced-choice paradigm, circled the word they thought they heard. Results indicated that accurate perception of final consonant voicing was not impaired by changes in the temporal structure of speech that accompanied the inexperienced signers' simultaneous communication. 相似文献
32.
To evaluate the effects of record length selection on the accuracy of spectral estimates of heart rate variability (HRV), a simulation study was carried out using a set of 58 signals obtained by autoregressive (AR) fitting a representative sample of real HRV signals. Four record lengths of 180, 300, 420, and 540 s were considered. Spectral estimation was performed by both the Blackman-Tukey (B-T) and AR methods. Accuracy was assessed for: (1) point spectral estimates, by computing the normalized averaged bias (NAB) and variance (NAV); and (2) the most commonly used spectral parameters [total power (TP) and the powers in the bands: very low frequency (VLF) (0÷0.04 Hz), low frequency (LF) (0.04÷0.15 Hz), and high frequency (HF) (0.15÷0.45 Hz)], by computing the normalized bias (NB) and variance (NV). The results are: whatever the record length considered, the 90th percentiles (90P) of the NAB were <10%, whereas those of the NB were <9% for TP, LF, and HF powers, and <14% for the VLF power, in both methods. The NAV was proportional to the reciprocal of record length, showing high 90P values for the shortest record length (26.4% for B-T and 44.2% for AR). The NV showed the same trend but 90P values were much lower (<8% for TP, LF, and HF powers and <19% for VLF power, in both methods). In the final part of the paper a procedure for the computation of approximate upper bounds of the relative absolute error of spectral measures at each record length, based on the knowledge of the NE and NV, is presented 相似文献
33.
The canonical problem of the radiation of an elementary dipole close to a stratified sphere representing a simplified model of human head is investigated in this paper. The proposed approach is a flexible method of investigation about the influence on Specific Absorption Rate (S.A.R.) evaluation of tissue dielectric parameters and geometry as well as a useful tool to test numerical codes. The solution of the electromagnetic (e.m.) problem is achieved in a closed form; results highlight the position of maximum S.A.R. values and their dependence on frequency: for particular layer thicknesses and dielectric parameters, the maximum absorption can occur in the frequency range of cellular phones. 相似文献
34.
G D'Elia G Lucandri F Stipa P Graziano R Gianotti D Castiglia M Barreca P Mingazzini V Ziparo S Stipa 《Canadian Metallurgical Quarterly》1996,17(11-12):597-601
Localized fibroma represents a rare entity arising from the pleura. Currently its histogenesis and clinical behaviour are still controversial. A case of a 64-year-old male is here presented; clinical and histopathological features are then discussed on the basis of a review of the Literature. At present, an en-bloc resection of the tumor, including wide margins of the surrounding lung tissue, seems to be the most appropriate surgical choice. 相似文献
35.
P Bertello F Veglio G Pinna L Gurioli P Molino S Alban L Chiandussi 《Canadian Metallurgical Quarterly》1994,17(6):574-577
OBJECTIVE: To measure plasma endothelin 1 (ET-1) levels in uncomplicated non-insulin-dependent diabetes mellitus (NIDDM) and investigate whether ET levels may be related to angiopathy, blood pressure, metabolic control, or duration of illness. RESEARCH DESIGN AND METHODS: Plasma levels of ET-1 were measured in 44 NIDDM patients, of whom 24 had uncomplicated diabetes, 20 had angiopathy, and 10 had hypertension. In 21 patients, the duration of illness was > 10 years, and in 23 the duration of illness was < 10 years. Serum creatinine levels, microalbuminuria, and HbA1c were determined simultaneously. Thirty normotensive healthy (nondiabetic) individuals (20 men and 10 women) served as control subjects. RESULTS: No significant statistical differences in plasma ET-1 levels were found among all diabetic patients, diabetic patients with and without angiopathy, diabetic patients with different durations of diabetes, and normal subjects. No significant correlation of plasma ET-1 with blood pressure, age, serum creatinine level, duration of diabetes, HbA1c, or diabetic complications was found. CONCLUSIONS: Plasma ET-1 levels are similar in patients with NIDDM and healthy subjects and do not seem to act as a marker of diabetic complications. 相似文献
36.
Casu M.R. Graziano M. Masera G. Piccinini G. Zamboni M. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2004,12(4):349-358
In this paper, a simple power-distribution electrothermal model including the interconnect self-heating is used together with a statistical model of average and rms currents of functional blocks and a high-level model of fanout distribution and interconnect wirelength. Following the 2001 SIA roadmap projections, we are able to predict a priori that the minimum width that satisfies the electromigration constraints does not scale like the minimum metal pitch in future technology nodes. As a consequence, the percentage of chip area covered by power lines is expected to increase at the expense of wiring resources unless proper countermeasures are taken. Some possible solutions are proposed in the paper. 相似文献
37.
Graziano Anthony M.; DeGiovanni Ina S.; Garcia Kathleen A. 《Canadian Metallurgical Quarterly》1979,86(4):804
Reviews behavioral literature on childhood fears, including conceptual models, normative research, and fear-reduction studies. The main conclusions are as follows: (a) The information value of nearly 60 yrs of normative studies is meager, and their continuation is of doubtful value. (b) Most research has been limited to laboratory studies of mildly to moderately fearful children, and few data exist on severe fears studied in the child's natural environment or on the clinical prevalence of fear. (c) Cognitive and developmental factors have been largely ignored. (d) Modeling is the most frequently used and reliably effective fear-reduction strategy. (e) A cognitive, verbal-mediation approach is promising but is not yet sufficiently researched. (f) There is little evidence that systematic desensitization or contingency management strategies are effective. Implications for large-scale fear reduction and prevention are discussed. The need for research that recognizes the complex paradigms of children's fears is suggested. (4 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
38.
Graziano William G.; Moore Janet S.; Collins James E. 《Canadian Metallurgical Quarterly》1988,24(4):568
This study examined the influence of familiarity with peers on social cognition in children. Second- and fourth-grade children were given information about an unfamiliar peer before viewing a videotape of that peer. Children were then instructed to segment the ongoing behavioral stream of the target peer into units by pressing a button. Extrapolating from research on the influence of expert knowledge on cognition, we predicted that children who were given prior information about the peer would break the behavioral stream into fewer, larger segments than would children in no-prior-information control conditions. We also predicted that prior information would exert more influence on the segmentation of fourth graders than that of second graders. Results were consistent with these hypotheses. These and other results are discussed in terms of developmental and contextual influences on social cognition in children. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
39.
Thermodynamic analysis of the effect of selective monodeamidation at asparagine 67 in ribonuclease A
Selective deamidation of proteins and peptides is a reaction of great interest, both because it has a physiological role and because it can cause alteration in the biological activity, local folding, and overall stability of the protein. In order to evaluate the thermodynamic effects of this reaction in proteins, we investigated the temperature-induced denaturation of ribonuclease A derivatives in which asparagine 67 was selectively replaced by an aspartyl residue or an isoaspartyl residue, as a consequence of an in vitro deamidation reaction. Differential scanning calorimetry measurements were performed in the pH range 3.0-6.0, where the unfolding process is reversible, according to the reheating criterion used. It resulted that the monodeamidated forms have a different thermal stability with respect to the parent enzyme. In particular, the replacement of asparagine 67 with an isoaspartyl residue leads to a decrease of 6.3 degrees C of denaturation temperature and 65 kJ mol-1 of denaturation enthalpy at pH 5.0. These results are discussed and correlated to the X-ray three-dimensional structure of this derivative. The analysis leads to the conclusion that the difference in thermal stability between RNase A and (N67isoD)RNase A is due to enthalpic effects arising from the loss of two important hydrogen bonds in the loop containing residue 67, partially counterbalanced by entropic effects. Finally, the influence of cytidine-2'-monophosphate on the stability of the three ribonucleases at pH 5.0 is studied and explained in terms of its binding on the active site of ribonucleases. The analysis makes it possible to estimate the apparent binding constant and binding enthalpy for the three proteins. 相似文献
40.