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排序方式: 共有1053条查询结果,搜索用时 31 毫秒
71.
Silole‐Based Red Fluorescent Organic Dots for Bright Two‐Photon Fluorescence In vitro Cell and In vivo Blood Vessel Imaging 下载免费PDF全文
Bin Chen Guangxue Feng Bairong He Chiching Goh Shidang Xu Gabriel Ramos‐Ortiz Laura Aparicio‐Ixta Jian Zhou Laiguan Ng Zujin Zhao Bin Liu Ben Zhong Tang 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(6):782-792
Robust luminescent dyes with efficient two‐photon fluorescence are highly desirable for biological imaging applications, but those suitable for organic dots fabrication are still rare because of aggregation‐caused quenching. In this work, a red fluorescent silole, 2,5‐bis[5‐(dimesitylboranyl)thiophen‐2‐yl]‐1‐methyl‐1,3,4‐triphenylsilole ((MesB)2DTTPS), is synthesized and characterized. (MesB)2DTTPS exhibits enhanced fluorescence efficiency in nanoaggregates, indicative of aggregation‐enhanced emission (AEE). The organic dots fabricated by encapsulating (MesB)2DTTPS within lipid‐PEG show red fluorescence peaking at 598 nm and a high fluorescence quantum yield of 32%. Upon excitation at 820 nm, the dots show a large two‐photon absorption cross section of 3.43 × 105 GM, which yields a two‐photon action cross section of 1.09 × 105 GM. These (MesB)2DTTPS dots show good biocompatibility and are successfully applied to one‐photon and two‐photon fluorescence imaging of MCF‐7 cells and two‐photon in vivo visualization of the blood vascular of mouse muscle in a high‐contrast and noninvasive manner. Moreover, the 3D blood vasculature located at the mouse ear skin with a depth of over 100 μm can also be visualized clearly, providing the spatiotemporal information about the whole blood vascular network. 相似文献
72.
In this paper, we consider dynamical graph-based models, which are well fitted for the structural analysis of complex systems. A significant amount of work has been devoted to the controllability of such graph based models, e.g. recently for multi-agent systems or complex networks. We study here the controllability through input addition in this framework. We present several variants of this problem depending on the freedom which is left to the designer on the additional inputs. We use a unified framework, which allows us to encompass the different applications and representations (large scale systems, complex communications networks, multi-agent systems, …) and provide convenient graph tools for their analysis. Our contribution is to characterize the structural modifications of the system resulting from an input addition (or a leader selection) and of the mechanisms which lead to controllability. We provide information on the possible location of additional inputs and on the minimal number of inputs to be added for controllability. 相似文献
73.
Shu Wei Goh Michelle Akin Zhanping You Xianming Shi 《Construction and Building Materials》2011,25(1):195-200
This paper reports on the potential benefits of micro- or nano-sized materials for asphalt mixtures used on pavements, specifically when they are exposed to water or deicing solutions. Asphalt mixtures were prepared with various amount of nanoclay and/or carbon microfiber, and compacted using the Superpave? gyratory compactor. Moisture susceptibility and deicer impacts were assessed by exposing the samples to water or deicing chemicals (NaCl, MgCl2 and CaCl2), and seven freeze–thaw cycles, in a modified AASHTO T283 test. Comparisons of micro- or nano-modified asphalt mixtures exposed to deicers are made based on results of indirect tensile strength tests, which preliminarily demonstrate the great potential of using microfibers and nanoclays in asphalt mixture for improved performance. Based on the results, it was found that the addition of nanoclay and carbon microfiber would improve a mixture’s moisture susceptibility performance or decrease the moisture damage potential in most cases. The detailed effects of deicing solutions on the tensile strength of micro- or nano- modified asphalt mixture are discussed in this paper. 相似文献
74.
T. Meissner S. K. Goh J. Haase B. Meier D. Rybicki P. L. Alireza 《Journal of Low Temperature Physics》2010,159(1-2):284-287
A novel approach that uses radio-frequency microcoils in the high-pressure region of anvil cells with Nuclear Magnetic Resonance (NMR) experiments is described. High-sensitivity Al NMR data at 70 kbar for Al metal are presented for the first time. An expected decrease in the Al Knight shift at 70 kbar is observed, as well as an unexpected change in the local charge symmetry at the Al nucleus. The latter is not predicted by chemical structure analysis under high pressure. 相似文献
75.
Reports an error in the original article by K. L. Dion (Group Dynamics: Theory, Research and Practice, 2001 [March], Vol 5[1], 7–26). In Table 1 on page 14, the value given in the GI-S row, column 4, was incorrect. The correct value is .72. The corrected table is provided. (The following abstract of this article originally appeared in record 2000-13580-002.) Psychological research on cohesion stems from contributions in the 1940s and 1950s by Festinger and his colleagues, who defined cohesion as a "field of forces" acting on individuals to remain in the group. In the 1950s, critics of this definition noted that different cohesion measures often failed to intercorrelate. By the mid-1960s, A. J. Lott and B. E. Lott (1965) conceptualized cohesion as interpersonal attraction because researchers mainly focused on this "force." Multidimensional models of cohesion predominated in the 1980s and 1990s, the debate now focused on defining those dimensions. In addition to A. V. Carron's (1988) hierarchical model, several bidimensional models are summarized, including task and social cohesion, vertical and horizontal cohesion, belongingness and morale, and personal versus social attraction. Cohesion will continue to be a vital construct in research on groups and … (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
76.
T. N. Goh 《Quality and Reliability Engineering International》2002,18(5):403-410
Six Sigma as a quality improvement framework has been gaining considerable attention in recent years. The hyperbole that often accompanied the presentation and adoption of Six Sigma in industry could lead to unrealistic expectations as to what Six Sigma is truly capable of achieving. In this paper, some strategic perspectives on the subject are presented, highlighting the potential and possible limitations of Six Sigma applications particularly in a knowledge‐based environment. Without delving into the mechanics of the subject in detail, the points raised could be useful to those deliberating on the appropriateness of Six Sigma to their respective organizations. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
77.
Extracts of 40 species of Chinese medicinal herb from 32 different botanical families were screened for contact, fumigant and feeding-deterrent activities against the two stored-grain insects Sitophilus zeamais and Tribolium castaneum. Thirty Chinese medicinal herbs exhibited insecticidal or feeding-deterrent activities against the two species of insects. Extracts of Artemisia argyi, Dictamnus dasycarpus, Evodia rutaecarpa, Litsea cubeba, Narcissus tazetta var. chinensis, Polygonum aviculare, Rhododendron molle, Sophora flavescens, Stemona sessilifolia, Tripterygium wilfordii, and Torreya grandis were most active. 相似文献
78.
A Rajnakova PM Goh ST Chan SS Ngoi A Alponat S Moochhala 《Canadian Metallurgical Quarterly》1997,18(9):1841-1845
The present study investigated the expression and distribution of three isoforms of nitric oxide synthase (NOS) in different anatomical regions of the human stomach and in gastric neoplastic tissues by immunohistochemistry using specific antibodies. Intracellular localization of individual isoenzymes of NOS was detected in normal gastric mucosa. Gastric cancer tissues had a marked reduction of all three NOS isoforms expression. The expression of the endothelial NOS, neuronal NOS and inducible NOS in the tumor tissue was significantly lower than in normal gastric mucosa (P = 0.01, P = 0.02, P < 0.01, respectively). In the tumor tissue the expression of inducible NOS was significantly lower than the expression of both constitutive forms of NOS (P < 0.01). There was a tendency to higher expression of both constitutive forms of NOS in earlier stages T2 of the tumor compared to advanced T4 tumor. In contrast, the expression of inducible NOS was higher than in the advanced T4 tumor than in the earlier stages T2 of the tumor. The mapping of the expression of endothelial NOS, neuronal NOS and inducible NOS in human stomach showed higher expression of NOS isoforms in the distal third than in the proximal third of the stomach (P = 0.03, P = 0.04, P = 0.01, respectively). We conclude that there is greater expression of NOS in the stomach corpus and in antrum than in the proximal third of the normal human stomach mirroring the anatomical predilection of common pathological changes in this part of the human stomach. Furthermore, there was loss of the expression of individual isoenzymes in gastric neoplasms. 相似文献
79.
A conditional decision procedure for high yield processes 总被引:1,自引:0,他引:1
A control chart based on the cumulative count of conforming items between two successive nonconforming ones has been shown to be useful in manufacturing industries, particularly for high-quality processes. However, as the decision is based on a single count value, it is relatively insensitive to process shifts. In this paper a conditional procedure is proposed whereby the sensitivity is improved when the process shift is moderate to large in either direction. In addition, optimal limits are defined in such a way that the average run length becomes maximum when the process average is at the nominal level. The performance of the conditional chart and its optimal limits are investigated and compared with the traditional case. The idea of a conditional procedure is to utilize some of the previous runs when a count value exceeds the limits. This procedure is similar to the supplementary run rules, but the conditional procedure is used when the process is out side of the control limits whereas the supplementary run rules focuses on the in-control situation. The conditional procedure has tighter limits than its original chart. The tighter limits together with the conditionality take care of the process without sacrificing its original in-control probability whilst improving the sensitivity. 相似文献
80.
The response surface methodology (RSM), particularly Box-Behnken design model, was used in this study to obtain the optimum operating conditions for reduction of copper corrosion by-product release using high-dose polyphosphate inhibition. Furthermore, the RSM was also applied to study the main and interactive effects of the parameters investigated. Both analysis of variance (ANOVA) and coefficient of determination (R2) showed that the RSM approach was appropriate for the optimization of high-dose polyphosphate inhibition. The main effects of polyphosphate dosage and pH were found significant in reducing copper release using high-dose polyphosphate whereas the effect of contact time was less significant. In terms of interactions between the effects, the relation between polyphosphate dosage and the pH was the most significant. The optimal polyphosphate dosage, pH and contact time were found to be 22-28 mg/L of polyphosphate as P, 9-10, and 36 h, respectively. The highest total copper release reduction was estimated as 95.86% under the optimum condition. Surface analysis using both SEM-EDX and XRD discovered that cupric phosphate was present on the copper surface treated with high-dose polyphosphate inhibition. This implied that cupric phosphate could be responsible for the reduction of copper release by forming a protective layer. 相似文献