全文获取类型
收费全文 | 464篇 |
免费 | 24篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 103篇 |
金属工艺 | 4篇 |
机械仪表 | 6篇 |
建筑科学 | 35篇 |
能源动力 | 32篇 |
轻工业 | 69篇 |
水利工程 | 4篇 |
石油天然气 | 1篇 |
无线电 | 30篇 |
一般工业技术 | 80篇 |
冶金工业 | 24篇 |
原子能技术 | 3篇 |
自动化技术 | 95篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 17篇 |
2021年 | 12篇 |
2020年 | 8篇 |
2019年 | 13篇 |
2018年 | 9篇 |
2017年 | 14篇 |
2016年 | 14篇 |
2015年 | 13篇 |
2014年 | 20篇 |
2013年 | 32篇 |
2012年 | 33篇 |
2011年 | 60篇 |
2010年 | 25篇 |
2009年 | 20篇 |
2008年 | 21篇 |
2007年 | 25篇 |
2006年 | 13篇 |
2005年 | 18篇 |
2004年 | 19篇 |
2003年 | 16篇 |
2002年 | 11篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 6篇 |
1989年 | 1篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有489条查询结果,搜索用时 31 毫秒
91.
Anker Morten G.; Owen Jesse; Duncan Barry L.; Sparks Jacqueline A. 《Canadian Metallurgical Quarterly》2010,78(5):635
Objective: The purpose of this study was to explore the relationship between the alliance and outcome in couple therapy and examine whether the alliance predicted outcomes over and above early change. The authors also investigated partner influence and gender and sought to identify couple alliance patterns that predicted couple outcomes. Method: The authors examined the alliances and outcomes at posttreatment and follow-up of 250 couples seeking treatment for marital distress in a naturalistic setting. The Session Rating Scale was used to measure the alliance; the Outcome Rating Scale and Locke Wallace Marital Adjustment Scale were used to measure outcomes. Couples were White, Euro-Scandinavian, and heterosexual, with a mean age of 38.5 years and average number of years together of 11.8. On a subsample (n = 118) that included couples with 4 or more sessions, the authors investigated the relationship between the alliance and outcome controlling for early change, and patterns of alliance development were delineated. Results: In the full sample, first-session alliances were not predictive of outcomes, but last-session alliances were predictive for both individuals and their partners. In the subsample, third-session alliances predicted outcome significantly above early change (d = 0.25) that exceeded the reliable change index. Couple alliances that started over the mean and increased were associated with significantly more couples achieving reliable or clinically significant change. Gender influences were mixed. Conclusions: Given the current findings suggesting a potential alliance impact over and above symptom relief as well as the importance of ascending alliance scores, continuous assessment of the alliance appears warranted. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
92.
Zhigang Zhu Lise Kristensen Gareth F. Difford Morten Poulsen Samantha J. Noel Waleed Abu Al-Soud Søren J. Sørensen Jan Lassen Peter Løvendahl Ole Højberg 《Journal of dairy science》2018,101(11):9847-9862
In the present study, we hypothesized that the rumen bacterial and archaeal communities would change significantly over the transition period of dairy cows, mainly as an adaptation to the classical use of low-grain prepartum and high-grain postpartum diets. Bacterial 16S rRNA gene amplicon sequencing of rumen samples from 10 primiparous Holstein dairy cows revealed no changes over the transition period in relative abundance of genera such as Ruminococcus, Butyrivibrio, Clostridium, Coprococcus, and Pseudobutyrivibrio. However, other dominant genus-level taxa, such as Prevotella, unclassified Ruminococcaceae, and unclassified Succinivibrionaceae, showed distinct changes in relative abundance from the prepartum to the postpartum period. Overall, we observed individual fluctuation patterns over the transition period for a range of bacterial taxa that, in some cases, were correlated with observed changes in the rumen short-chain fatty acids profile. Combined results from clone library and terminal-restriction fragment length polymorphism (T-RFLP) analyses, targeting the methyl-coenzyme M reductase α-subunit (mcrA) gene, revealed a methanogenic archaeal community dominated by the Methanobacteriales and Methanomassiliicoccales orders, particularly the genera Methanobrevibacter, Methanosphaera, and Methanomassiliicoccus. As observed for the bacterial community, the T-RFLP patterns showed significant shifts in methanogenic community composition over the transition period. Together, the composition of the rumen bacterial and archaeal communities exhibited changes in response to particularly the dietary changes of dairy cows over the transition period. 相似文献
93.
Allesø M Velaga S Alhalaweh A Cornett C Rasmussen MA van den Berg F de Diego HL Rantanen J 《Analytical chemistry》2008,80(20):7755-7764
Near-infrared (NIR) spectroscopy is a well-established technique for solid-state analysis, providing fast, noninvasive measurements. The use of NIR spectroscopy for polymorph screening and the associated advantages have recently been demonstrated. The objective of this work was to evaluate the analytical potential of NIR spectroscopy for cocrystal screening using Raman spectroscopy as a comparative method. Indomethacin was used as the parent molecule, while saccharin and l-aspartic acid were chosen as guest molecules. Molar ratios of 1:1 for each system were subjected to two types of preparative methods. In the case of saccharin, liquid-assisted cogrinding as well as cocrystallization from solution resulted in a stable 1:1 cocrystalline phase termed IND-SAC cocrystal. For l-aspartic acid, the solution-based method resulted in a polymorphic transition of indomethacin into the metastable alpha form retained in a physical mixture with the guest molecule, while liquid-assisted cogrinding did not induce any changes in the crystal lattice. The good chemical peak selectivity of Raman spectroscopy allowed a straightforward interpretation of sample data by analyzing peak positions and comparing to those of pure references. In addition, Raman spectroscopy provided additional information on the crystal structure of the IND-SAC cocrystal. The broad spectral line shapes of NIR spectra make visual interpretation of the spectra difficult, and consequently, multivariate modeling by principal component analysis (PCA) was applied. Successful use of NIR/PCA was possible only through the inclusion of a set of reference mixtures of parent and guest molecules representing possible solid-state outcomes from the cocrystal screening. The practical hurdle related to the need for reference mixtures seems to restrict the applicability of NIR spectroscopy in cocrystal screening. 相似文献
94.
Rasmussen IB Oynebråten I Høydahl LS Flobakk M Lunde E Michaelsen TE Bogen B Sandlie I 《Protein engineering, design & selection : PEDS》2012,25(3):89-96
CD4+ T lymphocytes play a central role in the orchestration and maintenance of the adaptive immune response. Targeting of antigen to antigen presenting cells (APCs) increases peptide loading of major histocompatibility complex (MHC) class II molecules and CD4+ T-cell activation. APCs have been targeted by APC-specific recombinant antibodies (rAbs) with single T-cell epitopes integrated in the constant region of the heavy chain (C(H)). However, the strategy may be improved if several T-cell epitopes could be delivered simultaneously by one rAb. We here demonstrate that a single rAb can be loaded with multiple identical or different T-cell epitopes, integrated as loops between β-strands in C(H) domains. One epitope was inserted in C(H)1, while two were placed in C(H)2 of IgG. T-cell proliferation assays showed that all three peptides were excised from loops and presented on MHC class II to T-cells. Induction of T-cell activation by each epitope in the multi-peptide rAb was as good, or even better, than that elicited by corresponding single-peptide rAbs. Furthermore, following DNA vaccination of mice with plasmids that encode CD40-specific rAbs loaded with either one or three peptides, T-cell responses were induced. Thus, integration of multiple epitopes in C(H) region loops of APC-specific rAbs is feasible and may be utilized in design of multi-vaccines. 相似文献
95.
A drainage/filtration apparatus was developed for automatically determining sedimentation velocity and dewatering rate. Pressure-step testing was used to study filter cake compressibility, resistance, and swelling. Activated sludge was analysed, and the data indicate that the sludge is highly compressible even at low pressures (10 kPa). Furthermore, compressed sludge cakes swell if the pressure is released. Hence, the average specific cake resistance decreases if the pressure is released, though the resistance is higher after the compression cycle than before. Sludge must be dewatered under low pressure, because higher pressure only compresses the cake and does not improve the dewatering rate. 相似文献
96.
Mohseni HR Woolrich MW Kringelbach ML Luckhoo H Smith PP Aziz TZ 《IEEE transactions on bio-medical engineering》2012,59(7):1951-1961
Novel neuroimaging techniques have provided unprecedented information on the structure and function of the living human brain. Multimodal fusion of data from different sensors promises to radically improve this understanding, yet optimal methods have not been developed. Here, we demonstrate a novel method for combining multichannel signals. We show how this method can be used to fuse signals from the magnetometer and gradiometer sensors used in magnetoencephalography (MEG), and through extensive experiments using simulation, head phantom and real MEG data, show that it is both robust and accurate. This new approach works by assuming that the lead fields have multiplicative error. The criterion to estimate the error is given within a spatial filter framework such that the estimated power is minimized in the worst case scenario. The method is compared to, and found better than, existing approaches. The closed-form solution and the conditions under which the multiplicative error can be optimally estimated are provided. This novel approach can also be employed for multimodal fusion of other multichannel signals such as MEG and EEG. Although the multiplicative error is estimated based on beamforming, other methods for source analysis can equally be used after the lead-field modification. 相似文献
97.
Farmer Thomas A.; Monaghan Padraic; Misyak Jennifer B.; Christiansen Morten H. 《Canadian Metallurgical Quarterly》2011,37(5):1318
In 2 separate self-paced reading experiments, Farmer, Christiansen, and Monaghan (2006) found that the degree to which a word's phonology is typical of other words in its lexical category influences online processing of nouns and verbs in predictive contexts. Staub, Grant, Clifton, and Rayner (2009) failed to find an effect of phonological typicality when they combined stimuli from the separate experiments into a single experiment. We replicated Staub et al.'s experiment and found that the combination of stimulus sets affects the predictiveness of the syntactic context; this reduces the phonological typicality effect as the experiment proceeds, although the phonological typicality effect was still evident early in the experiment. Although an ambiguous context may diminish sensitivity to the probabilistic relationship between the sound of a word and its lexical category, phonological typicality does influence online sentence processing during normal reading when the syntactic context is predictive of the lexical category of upcoming words. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
98.
Daniel Minzari Morten S. Jellesen Per Møller Rajan Ambat 《Engineering Failure Analysis》2011,18(8):2126-2136
A silicone coated power module, having silver conducting lines, showed severe corrosion, after prolonged use as part of an electronic device in a pig farm environment, where sulfur containing corrosive gasses are known to exist in high amounts. Permeation of sulfur gasses and humidity through the silicone coating to the interface has resulted in three corrosion types namely: uniform corrosion, conductive anodic filament type of Ag2S growth, and silver migration with subsequent formation of sulfur compounds. Detailed morphological investigation of new and corroded power modules was carried out, and possible theoretical explanation for various corrosion mechanisms has been attempted. 相似文献
99.
The objectives of the study were: to evaluate the interaction between visual appearance and California mastitis test (CMT) score of the foremilk in relation to the cell count of the milk; to evaluate the consequences of sorting milk according to these criteria; and to explore whether visual appearance and CMT score of foremilk depended on the time interval between milkings. Measuring somatic cell count (SCC) in composite milk only and discarding milk above certain thresholds will not ensure that milk from all cows with visually abnormal foremilk is withheld from delivery. Low thresholds of SCC will reduce the frequency of cows with abnormal milk but increase the discarding of milk from cows with visually normal foremilk. CMT score of foremilk differentiated better between cows with high and low SCC in composite milk than visual inspection of foremilk. CMT scores of foremilk decreased with increasing interval between milkings within cow, whereas the visual appearance was independent of the interval. We propose that visual appearance of the foremilk should be kept as a criterion for sorting milk at time of milking. For test purposes, the use of visual appearance of foremilk for differentiation between normal and abnormal milk has to be done on multiple milkings. Additionally, CMT scoring of foremilk improves correct classification of normal and abnormal quarters and especially when including data from the previous milking. 相似文献
100.
Bjørn T. Rotabakk Sveinung Birkeland Willy K. Jeksrud Morten Sivertsvik 《Journal of food science》2006,71(2):S124-S131
The suitability of soluble gas stabilization (SGS) to dissolve CO2 into skinless chicken breast fillets before modified atmosphere (MA) packaging (MAP) was investigated. Head space gas composition (%), top web deflation (mm), muscle surface color (Minolta L*a*b*), pH, exudates in the packages (%), microbial characteristics, and off‐odor were assessed in the packaged fillets. Increased SGS treatment time (2 versus 12 h) before MA packaging increased the CO2 content in the packaged fillets and counteracted package collapse. High package filling degree (51.8%) (low gas to product volume ratio) gave significantly (P < 0.001) lower CO2 content in head space than normal filling degree (29.7%). Color, pH, and package exudates were not affected by SGS treatment. Aerobic plate count (APC), Enterbacteriaceae count (EC), and lactic acid bacteria (LAB) increased significantly (P < 0.001) at each sampling during storage (5, 11, 17, and 24 d). SGS treatment significantly (P < 0.015) decreased APC, EC, and Pseudomonas spp. counts (PC) compared with no SGS treatment. Filling degree did not have a significant effect on the investigated microbiological characteristics. Off‐odor scores correlated highest with EC (r2(adj)= 0.82). Fillets SGS treated in 12 h were the only one not rejected at off‐odor evaluation on day 24. The samples stored in air spoiled after 5 d. SGS treatment in combination with MAP can be used successfully on chicken breast fillets to improve the microbiological (APC, EC, and PC) and sensorial characteristics, and in addition reduce package collapse and possibly increase the filling degree. 相似文献