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51.
Actions performed by a virtual character can be controlled with verbal commands such as ‘walk five steps forward’. Similar control of the motion style, meaning how the actions are performed, is complicated by the ambiguity of describing individual motions with phrases such as ‘aggressive walking’. In this paper, we present a method for controlling motion style with relative commands such as ‘do the same, but more sadly’. Based on acted example motions, comparative annotations, and a set of calculated motion features, relative styles can be defined as vectors in the feature space. We present a new method for creating these style vectors by finding out which features are essential for a style to be perceived and eliminating those that show only incidental correlations with the style. We show with a user study that our feature selection procedure is more accurate than earlier methods for creating style vectors, and that the style definitions generalize across different actors and annotators. We also present a tool enabling interactive control of parametric motion synthesis by verbal commands. As the control method is independent from the generation of motion, it can be applied to virtually any parametric synthesis method. 相似文献
52.
Human eye-head co-ordination in natural exploration 总被引:1,自引:0,他引:1
Einhäuser W Schumann F Bardins S Bartl K Böning G Schneider E König P 《Network (Bristol, England)》2007,18(3):267-297
During natural behavior humans continuously adjust their gaze by moving head and eyes, yielding rich dynamics of the retinal input. Sensory coding models, however, typically assume visual input as smooth or a sequence of static images interleaved by volitional gaze shifts. Are these assumptions valid during free exploration behavior in natural environments? We used an innovative technique to simultaneously record gaze and head movements in humans, who freely explored various environments (forest, train station, apartment). Most movements occur along the cardinal axes, and the predominance of vertical or horizontal movements depends on the environment. Eye and head movements co-occur more frequently than their individual statistics predicts under an independence assumption. The majority of co-occurring movements point in opposite directions, consistent with a gaze-stabilizing role of eye movements. Nevertheless, a substantial fraction of eye movements point in the same direction as co-occurring head movements. Even under the very most conservative assumptions, saccadic eye movements alone cannot account for these synergistic movements. Hence nonsaccadic eye movements that interact synergistically with head movements to adjust gaze cannot be neglected in natural visual input. Natural retinal input is continuously dynamic, and cannot be faithfully modeled as a mere sequence of static frames with interleaved large saccades. 相似文献
53.
Giesen J Mueller K Schuberth E Wang L Zolliker P 《IEEE transactions on visualization and computer graphics》2007,13(6):1664-1671
Visualization algorithms can have a large number of parameters, making the space of possible rendering results rather high-dimensional. Only a systematic analysis of the perceived quality can truly reveal the optimal setting for each such parameter. However, an exhaustive search in which all possible parameter permutations are presented to each user within a study group would be infeasible to conduct. Additional complications may result from possible parameter co-dependencies. Here, we will introduce an efficient user study design and analysis strategy that is geared to cope with this problem. The user feedback is fast and easy to obtain and does not require exhaustive parameter testing. To enable such a framework we have modified a preference measuring methodology, conjoint analysis, that originated in psychology and is now also widely used in market research. We demonstrate our framework by a study that measures the perceived quality in volume rendering within the context of large parameter spaces. 相似文献
54.
One of the cornerstones of expert performance in complex domains is the ability to perceive problem situations in terms of
their task-relevant semantic properties. One such class of properties consists of phenomena that are defined in terms of patterns
of change over time, i.e., events. A basic pre-requisite for working towards tools to support event recognition is a method for understanding the events that
expert practitioners find meaningful in a given field of practice. In this article we present the modified unit marking procedure
(mUMP), a technique adapted from work on social perception to facilitate identification of the meaningful phenomena which
observers attend to in a dynamic data array. The mUMP and associated data analysis techniques are presented with examples
from a first of a kind study where they were used to elicit and understand the events practitioners found meaningful in a
scenario from an actual complex work domain.
相似文献
David D. WoodsEmail: |
55.
Braunschweig T Kaserer K Chung JY Bilke S Krizman D Knezevic V Hewitt SM 《Proteomics. Clinical applications》2007,1(3):264-271
Thyroid cancer is the most common endocrine neoplasm with multiple histologic subtypes, each associated with different treatments and outcomes. Differentiating benign neoplasms such as follicular adenomas from malignant entities such as follicular carcinomas and papillary carcinoma can be challenging. To define the proteomic profile of different thyroid tumors, we screened an antibody array of 330 features against five thyroid neoplasms: follicular adenoma, follicular carcinoma, papillary carcinoma, anaplastic carcinoma, and medullary carcinoma as well as normal thyroid epithelium. Eight candidate biomarkers; c-erbB-2, Stat5a, Annexin IV, IL-11, RARα, FGF7, Caspase 9, and phospho-c-myc were identified as differentially expressed on the antibody array, and validated with immunohistochemistry on tissue microarrays, with a total of 144 samples of the same variety of thyroid neoplasms. Analysis revealed c-erbB-2, Annexin IV, and Stat5a have potential clinical utility to differentiate follicular adenoma, follicular carcinoma, and papillary carcinoma from each other. By using an antibody array as a discovery platform and a tissue microarray as a first step in validation on a large number of specimens, we have identified new markers that have potential utility in the diagnosis of thyroid neoplasms. 相似文献
56.
Klaus W. Schwarz 《Journal of Low Temperature Physics》1993,93(5-6):1019-1029
The behavior of nucleated vortex loops and of remanent vortex filaments in idealized circular and slit-like orifices has been investigated by direct computation. It is found that such vortices can be stretched by the diverging flow on the exit side of the orifice. The energy needed to stretch the vortex is abstracted from the flow field and observed as dissipation. This occurs in the form of discrete phase-slip events in the case of nucleated vortex loops, and in the form of multiple-phase-slip cascades when a remanent vortex is involved. 相似文献
57.
Generating feature spaces for linear algorithms with regularized sparse kernel slow feature analysis
Wendelin B?hmer Steffen Grünew?lder Hannes Nickisch Klaus Obermayer 《Machine Learning》2012,89(1-2):67-86
Without non-linear basis functions many problems can not be solved by linear algorithms. This article proposes a method to automatically construct such basis functions with slow feature analysis (SFA). Non-linear optimization of this unsupervised learning method generates an orthogonal basis on the unknown latent space for a given time series. In contrast to methods like PCA, SFA is thus well suited for techniques that make direct use of the latent space. Real-world time series can be complex, and current SFA algorithms are either not powerful enough or tend to over-fit. We make use of the kernel trick in combination with sparsification to develop a kernelized SFA algorithm which provides a powerful function class for large data sets. Sparsity is achieved by a novel matching pursuit approach that can be applied to other tasks as well. For small data sets, however, the kernel SFA approach leads to over-fitting and numerical instabilities. To enforce a stable solution, we introduce regularization to the SFA objective. We hypothesize that our algorithm generates a feature space that resembles a Fourier basis in the unknown space of latent variables underlying a given real-world time series. We evaluate this hypothesis at the example of a vowel classification task in comparison to sparse kernel PCA. Our results show excellent classification accuracy and demonstrate the superiority of kernel SFA over kernel PCA in encoding latent variables. 相似文献
58.
Alexander Stocker Alexander Richter Patrick Hoefler Klaus Tochtermann 《Computer Supported Cooperative Work (CSCW)》2012,21(2-3):317-356
The purpose of this paper is to provide both application-oriented researchers and practitioners with detailed insights into conception, implementation, and utilization of intra-organizational wikis to support knowledge management and group work. Firstly, we report on three case studies and describe how wikis have been appropriated in the context of a concrete practice. Our study reveals that the wikis have been used as Knowledge Base, Encyclopedia and Support Base, respectively. We present the identified practices as a result of the wiki appropriation process and argue that due to their open and flexible nature these wikis have been appropriated according to the users’ needs. Our contribution helps to understand how platforms support working practices that have not been supported by groupware before, or at least not in the same way. Secondly, three detailed implementation reports uncover many aspects of wiki projects, e.g., different viewpoints of managers and users, an investigation of other sources containing business-relevant information, and perceived obstacles to wiki projects. In this context, our study generates a series of lessons learned for people who intend to implement wikis in their own organizations, including the awareness of usage potential, the need for additional managerial support, and clear communication strategies to promote wiki usage. 相似文献
59.
Jørgensen MB Faber A Jespersen T Hansen K Ektor-Andersen J Hansen JV Holtermann A Søgaard K 《Ergonomics》2012,55(7):762-772
This study evaluates the implementation of physical coordination training (PCT) and cognitive behavioural training (CBTr) interventions in a randomised controlled trial at nine cleaners' workplaces. Female cleaners (n = 294) were randomised into a PCT, a CBTr or a reference (REF) group. Both 12-week interventions were performed in groups guided by an instructor. Records were kept on intervention dose (adherence) unanticipated events at the work place (context) and quality of intervention delivery (fidelity). Participant adherence was 37% in the PCT and 49% in the CBTr interventions. Optimal implementation was reached by only 6% in PCT and 42% in the CBTr. Analysis of the barriers to successful implementation indicated that the intervention process is sensitive to unanticipated events. In order to succeed in improving the health of high-risk populations such as cleaners and to correctly interpret intervention effects, more research on implementation is needed. Trial registration: ISRCTN96241850. PRACTITIONER SUMMARY: Both physical coordination training and cognitive behavioural training are potential effective workplace interventions among low educated job groups with high physical work demands. However, thorough consideration should be given to feasibility in the design of interventions. The optimal intervention should be tailored to closely match the implementation context and be robust and flexible to minimise susceptibility to changes in work organisation. 相似文献
60.
Bernd Altmayer Klaus W. Eichhorn und Roland Plapp 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1982,175(3):172-174
Zusammenfassung Traubenmoste aus dem Weinanbaugebiet der Rheinpfalz wurden auf ihren Patulingehalt untersucht. Nach Extraktion und Reinigung wurde Patulin mit Hilfe der Hochleistungsflilssig- und Dünnschichtchromatographie bestimmt. Zur Extraktion des Patulins erwies sich die Verwendung von Extrelutsdulen als vorteilhaft. In 62% der untersuchten Proben (55) war kein Patulin nachweisbar, 22% enthielten weniger als 50 g, 16% mehr als 50 g Patulin pro Liter. Durch praxisübliche Mostschwefelung (100 mg Kaliumpyrosulîit/1) und Vergärung mit Hefen der GattungSaccharomyces konnte vorhandenes Patulin entfernt werden.
Analysis of patulin in grape juices and wine
Summary Grape juices from the wine-growing region of the palatinate Rheinpfalz were analysed for patulin. After extraction and purification patulin was determined by high performance liquid chromatography and thin layer chromatography. The use of Extrelut-columns for the extraction of patulin was found advantageous. 62% of the analysed samples (55) were free of patulin, 22% contained less than 50 g/l, 16% more than 50 g/l. By addition of sulfur dioxide to the must and fermentation withSaccharomyces sp. patulin could be removed from the samples.相似文献