全文获取类型
收费全文 | 419篇 |
免费 | 4篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 45篇 |
金属工艺 | 4篇 |
机械仪表 | 7篇 |
建筑科学 | 19篇 |
能源动力 | 1篇 |
轻工业 | 12篇 |
水利工程 | 1篇 |
无线电 | 21篇 |
一般工业技术 | 36篇 |
冶金工业 | 227篇 |
原子能技术 | 2篇 |
自动化技术 | 44篇 |
出版年
2022年 | 3篇 |
2021年 | 4篇 |
2019年 | 5篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 23篇 |
2012年 | 7篇 |
2011年 | 12篇 |
2010年 | 9篇 |
2009年 | 6篇 |
2008年 | 6篇 |
2007年 | 8篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 9篇 |
2000年 | 6篇 |
1999年 | 9篇 |
1998年 | 36篇 |
1997年 | 22篇 |
1996年 | 15篇 |
1995年 | 13篇 |
1994年 | 11篇 |
1993年 | 8篇 |
1992年 | 6篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 14篇 |
1987年 | 14篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 14篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1978年 | 8篇 |
1977年 | 9篇 |
1976年 | 10篇 |
1975年 | 4篇 |
1972年 | 4篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1967年 | 3篇 |
1962年 | 2篇 |
1958年 | 2篇 |
1957年 | 3篇 |
排序方式: 共有423条查询结果,搜索用时 15 毫秒
1.
O'Driscoll Michael P.; Poelmans Steven; Spector Paul E.; Kalliath Thomas; Allen Tammy D.; Cooper Cary L.; Sanchez Juan I. 《Canadian Metallurgical Quarterly》2003,10(4):326
This study examined organizational family-responsive policies, perceptions of the organization as family supportive, and supervisor support as issues that may be salient to the experience of conflict between paid employment (work) and family roles. Data were collected from 355 managerial personnel in New Zealand. Although work-family conflict and psychological strain were strongly linked, the availability of organizational policies had no significant association with levels of conflict or strain, whereas policy usage was related only to work-to-family interference and not to family-to-work interference. On the other hand, perceptions of the organization as family supportive and supervisor support for work-family balance displayed significant relationships with key variables, highlighting the importance of these variables for interventions designed to ameliorate the negative impact of work-family conflict on managerial well-being. Implications for the effective implementation of family-responsive interventions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
2.
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
3.
4.
Chorda tympani nerve (CT) transection in rats severely impairs NaCl taste detection. These rats can detect higher concentrations of NaCl, however, suggesting that remaining oral nerves maintain some salt sensibility. Rats were tested in a gustometer with a 2-response operant taste-detection task before and after sham surgery (n = 5), combined transection of the CT and the greater superficial petrosal nerves (GSP; 7x, n = 6), or transection of the glossopharyngeal nerve (GL; 9x, n = 4). Thresholds did not significantly change after sham surgery. Although the GL responds to NaCl and innervates nearly 60% of total taste buds, 9x surgery had no effect. However, 7x surgery increased NaCl detection threshold by ~2.5 log?? units, greater than that reported for CT transection alone. These results suggest that the GSP contributes to NaCl sensitivity in rats and also demonstrate that the GL and perhaps the superior laryngeal and lingual nerve proper can maintain some NaCl detectability at high concentrations. These findings confirm the primacy of the 7th nerve relative to the 9th nerve in sensibility of NaCl in the rat model. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
JF Cáceres T Misteli GR Screaton DL Spector AR Krainer 《Canadian Metallurgical Quarterly》1997,138(2):225-238
SR proteins are required for constitutive pre-mRNA splicing and also regulate alternative splice site selection in a concentration-dependent manner. They have a modular structure that consists of one or two RNA-recognition motifs (RRMs) and a COOH-terminal arginine/serine-rich domain (RS domain). We have analyzed the role of the individual domains of these closely related proteins in cellular distribution, subnuclear localization, and regulation of alternative splicing in vivo. We observed striking differences in the localization signals present in several human SR proteins. In contrast to earlier studies of RS domains in the Drosophila suppressor-of-white-apricot (SWAP) and Transformer (Tra) alternative splicing factors, we found that the RS domain of SF2/ASF is neither necessary nor sufficient for targeting to the nuclear speckles. Although this RS domain is a nuclear localization signal, subnuclear targeting to the speckles requires at least two of the three constituent domains of SF2/ASF, which contain additive and redundant signals. In contrast, in two SR proteins that have a single RRM (SC35 and SRp20), the RS domain is both necessary and sufficient as a targeting signal to the speckles. We also show that RRM2 of SF2/ASF plays an important role in alternative splicing specificity: deletion of this domain results in a protein that, although active in alternative splicing, has altered specificity in 5' splice site selection. These results demonstrate the modularity of SR proteins and the importance of individual domains for their cellular localization and alternative splicing function in vivo. 相似文献
6.
A microstructural analysis of licking behavior in nondeprived and 23-hr food-deprived rats (n = 15) presented with various sucrose solutions (0.03-1.0 M) in daily single-bottle, 1-hr sessions was conducted. Food deprivation and concentration interacted to increase total licks. The effects of food deprivation and concentration on burst size (BS), burst number (BN), and other parameters varied as a function of the pause criterion (PC; 0.3-100 s) used to define licking bursts. A rationale for selecting a 1-s PC for further analysis is presented. Despite the lack of correlations between temporally contiguous burst and pause combinations, mean BS decreased and pause duration increased as meals progressed. At the 1-s PC, BS increased linearly with concentration, implying that this microstructural parameter is influenced in part by taste. Food deprivation did not affect BS but rather increased BN and proportionally extended the meal duration. 相似文献
7.
8.
Biomass fed synthetic influent in an anaerobic/oxic automatic batch fill and draw apparatus was analyzed to determine which metal ions are involved along with polyphosphate accumulation. The biomass analysis indicates that the major elements are Mg and K. The data further indicate that the divalent cations Mg and Ca are responsible for balancing 2/3, and the monovalent cations K and Na 1/3 of the charge in the polyphosphate. Analysis of the filtered aqueous phase indicated that Mg, K and P were released from the biomass during the initial anaerobic zone and removed from the aqueous phase to the biomass during the subsequent aerobic zone. 相似文献
9.
Dennis D. Pietronigro Myron L. Seligman W. Barrie G. Jones Harry B. Demopoulos 《Lipids》1976,11(11):808-813
Deoxyribonucleic acid (DNA) is associated with the cell membrane of prokaryotes and the inner nuclear membrane of eukaryotes.
The unsaturated fatty acids of phospholipids, which constitute the bilaminar structure of membranes, undergo autoxidation
in the presence of O2. Calf thymus DNA was incubated with methyl archidonate-enriched phosphatidyl choline liposomes in order to study the effect
of DNA upon the oxidation of phospholipids while present in their natural in vivo bilayer configuration. DNA retarded the
rate of lipid oxidation and the TBA test, but it did not alter the induction period. These results suggest that DNA is scavenging
free radicals produced within the phospholipid bilayer. 相似文献
10.
We report the 2.2 A resolution structure of the Drosophila engrailed homeodomain bound to its optimal DNA site. The original 2.8 A resolution structure of this complex provided the first detailed three-dimensional view of how homeodomains recognize DNA, and has served as the basis for biochemical studies, structural studies and molecular modeling. Our refined structure confirms the principal conclusions of the original structure, but provides important new details about the recognition interface. Biochemical and NMR studies of other homeodomains had led to the notion that Gln50 was an especially important determinant of specificity. However, our refined structure shows that this side-chain makes no direct hydrogen bonds to the DNA. The structure does reveal an extensive network of ordered water molecules which mediate contacts to several bases and phosphates (including contacts from Gln50), and our model provides a basis for detailed comparison with the structure of an engrailed Q50K altered-specificity variant. Comparing our structure with the crystal structure of the free protein confirms that the N and C termini of the homeodomain become ordered upon DNA-binding. However, we also find that several key DNA contact residues in the recognition helix have the same conformation in the free and bound protein, and that several water molecules also are "preorganized" to contact the DNA. Our structure helps provide a more complete basis for the detailed analysis of homeodomain-DNA interactions. 相似文献