首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   923篇
  免费   38篇
  国内免费   2篇
电工技术   13篇
综合类   1篇
化学工业   184篇
金属工艺   10篇
机械仪表   19篇
建筑科学   36篇
矿业工程   6篇
能源动力   20篇
轻工业   137篇
水利工程   7篇
石油天然气   2篇
无线电   54篇
一般工业技术   147篇
冶金工业   222篇
原子能技术   4篇
自动化技术   101篇
  2023年   20篇
  2022年   7篇
  2021年   49篇
  2020年   20篇
  2019年   24篇
  2018年   24篇
  2017年   20篇
  2016年   28篇
  2015年   21篇
  2014年   25篇
  2013年   46篇
  2012年   49篇
  2011年   64篇
  2010年   50篇
  2009年   37篇
  2008年   55篇
  2007年   43篇
  2006年   45篇
  2005年   30篇
  2004年   20篇
  2003年   24篇
  2002年   21篇
  2001年   17篇
  2000年   13篇
  1999年   14篇
  1998年   31篇
  1997年   17篇
  1996年   21篇
  1995年   16篇
  1994年   10篇
  1993年   12篇
  1992年   9篇
  1991年   3篇
  1990年   7篇
  1989年   4篇
  1988年   5篇
  1987年   5篇
  1986年   5篇
  1985年   5篇
  1984年   3篇
  1982年   7篇
  1981年   5篇
  1979年   4篇
  1978年   6篇
  1977年   3篇
  1976年   6篇
  1975年   2篇
  1974年   2篇
  1972年   2篇
  1971年   2篇
排序方式: 共有963条查询结果,搜索用时 218 毫秒
1.
Shared metabolomic patterns at delivery have been suggested to underlie the mother-to-child transmission of adverse metabolic health. This study aimed to investigate whether mothers with gestational diabetes mellitus (GDM) and their offspring show similar metabolomic patterns several years postpartum. Targeted metabolomics (including 137 metabolites) was performed in plasma samples obtained during an oral glucose tolerance test from 48 mothers with GDM and their offspring at a cross-sectional study visit 8 years after delivery. Partial Pearson’s correlations between the area under the curve (AUC) of maternal and offspring metabolites were calculated, yielding so-called Gaussian graphical models. Spearman’s correlations were applied to investigate correlations of body mass index (BMI), Matsuda insulin sensitivity index (ISI-M), dietary intake, and physical activity between generations, and correlations of metabolite AUCs with lifestyle variables. This study revealed that BMI, ISI-M, and the AUC of six metabolites (carnitine, taurine, proline, SM(-OH) C14:1, creatinine, and PC ae C34:3) were significantly correlated between mothers and offspring several years postpartum. Intergenerational metabolite correlations were independent of shared BMI, ISI-M, age, sex, and all other metabolites. Furthermore, creatinine was correlated with physical activity in mothers. This study suggests that there is long-term metabolic programming in the offspring of mothers with GDM and informs us about targets that could be addressed by future intervention studies.  相似文献   
2.
3.
4.
Two studies examined whether the accessibility of performance prototypes influences performance appraisals. Pilot studies revealed students used performance prototypes when rating instructor performance. Study 1 manipulated the accessibility of these prototypes and the time delay of performance ratings. Results showed no effect of the prime on rating error and accuracy; however, discrimination accuracy decreased over time and recognition bias became more conservative. Study 2 manipulated prototype accessibility and type of rating stimuli (videotape vs. vignette). Rating accuracy and recall were higher for vignette than videotape stimuli, and only those participants exposed to the vignette exhibited priming effects. Results supported transfer-appropriate processing and implied that cognitive primes may have a stronger effect on performance ratings based on "paper-people" than videotaped stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
Emissions of ultrasonic vocalizations (USVs) by rat pups (Rattus norvegicus) during hypothermia have consequences for recovery and warming. The effects on dam behavior of USVs emitted by 3- to 11-day-old pups during hypothermia at rectal temperatures between 18 and 22°C was investigated Rat dams were tested in a Y maze with the home cage as a start box. Dams were given, in one condition, a choice between a hypothermic pup emitting USVs or a hypothermic, silent (anesthetized) pup and, in the other, a choice between 2 hypothermic, silent pups. Although differing in some acoustic properties from normal isolation calls, USVs emitted by hypothermic pups both elicited maternal search behavior and acted as directional cues for dams, in comparisons with control dams exposed only to silent pups. Thus USVs of pups recovering from extreme hypothermia have communicative as well as physiological significance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
6.
The Mean Opinion Scale (MOS) is a questionnaire used to obtain listeners' subjective assessments of synthetic speech. This paper documents the motivation, method, and results of six experiments conducted from 1999 to 2002 that investigated the psychometric properties of the MOS and expanded the range of speech characteristics it evaluates. Our initial experiments documented the reliability, validity, sensitivity, and factor structure of the P.L. Salza et al. (Acta Acustica, Vol. 82, pp. 650–656, 1996) MOS and used psychometric principles to revise and improve the scale. This work resulted in the MOS-Revised (MOS-R). Four subsequent experiments expanded the MOS-R beyond its previous focus on Intelligibility and Naturalness, to include measurement of the Prosody and Social Impression of synthetic voices. As a result of this work, we created the MOS-Expanded (MOS-X), a rating scale shown to be reliable, valid, and sensitive for high-quality evaluation of synthetic speech in applied industrial settings.  相似文献   
7.
8.
9.
Ti–B–N films with a gradient in the chemical composition were deposited onto austenitic stainless steel sheets by means of unbalanced DC magnetron co-sputtering using a segmented TiN\Tib2 target. Film microstructure was characterized by means of electron-probe microanalysis (EPMA), transmission electron microscopy (TEM), electron energy-loss spectroscopy (EELS), and X-ray diffraction (XRD) as well as glancing angle X-ray diffraction (GAXRD). The mechanical properties of the coatings were measured using a depth-sensing nanoindenter. The composition of the films was found to lie close to the quasi-binary section TiN–TiB2 within the ternary system Ti–B–N. The grain size determined from TEM investigations range between 3 and 5 nm. Coatings consisted of a nanocrystalline fcc TiN phase (with boron atoms and oxygen impurities dissolved), and TiB2, TiB and B2O3. Microstructure as well as chemical composition of the films were not influenced significantly by the deposition parameters used in this investigation. Contrary, the mechanical properties were strongly influenced varying the ion bombardment. Hardness values exceeding 50 GPa and elastic moduli close to 500 GPa were obtained.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号