全文获取类型
收费全文 | 147篇 |
免费 | 4篇 |
学科分类
工业技术 | 151篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2016年 | 1篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 9篇 |
2011年 | 5篇 |
2010年 | 10篇 |
2009年 | 6篇 |
2008年 | 8篇 |
2007年 | 11篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1979年 | 1篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有151条查询结果,搜索用时 0 毫秒
101.
The authors show that the updating of working memory (WM) representations is carried out by the cooperative act of 2 dissociable reaction time (RT) components: a global updating process that provides stability by shielding WM contents against interference and a local process that provides flexibility. Participants kept track of 1?3 items (digits or Gibson figures). In each trial, the items either were similar to those in the previous trial or were different in any or all of the items. Experiments 1 and 2 established the existence of 2 independent RT components representing the 2 updating processes. Global updating cost was sensitive to total number of items in WM (set size), regardless of the number of items that actually were modified. Local updating cost was sensitive to the number of modified items, regardless of the set size. Experiment 3 showed that participants had to dismantle the representation formed by previous global updating in order to carry out new updating. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
102.
K. R. Kinsman E. Eichen H. I. Aaronson 《Metallurgical and Materials Transactions A》1975,6(2):303-317
Thermionic electron emission microscopy was used to measure directly the thickening kinetics of proeutectoid ferrite sideplates in Fe-C alloys. These kinetics were found to be exceedingly irregular. During the first few seconds of growth, the thickening rate is 5 xl0-5±1 cm/s; afterwards it usually diminishes to 1 - 30 × 10-6 cm/s. As predicted by a general theory of precipitate morphology, thickening was shown to occur only by the ledge mechanism, despite the relatively poor matching of the austenite and the ferrite lattices. Ledges were observed to lengthen at rates controlled by the diffusion of carbon in austenite. Tent-shaped and other more complex surface relief effects, rather than the invariant plane strain relief, were found to predominate. These features are shown to be the expected result of a diffusional transformation occurring by means of a ledge mechanism. 相似文献
103.
Huntsinger Jeffrey R.; Clore Gerald L.; Bar-Anan Yoav 《Canadian Metallurgical Quarterly》2010,10(5):722
Positive moods promote a focus on the forest (global focus) and negative moods, a focus on the trees (local focus). Is this well-established link fixed or variable? Does it reflect a direct influence of affect, as usually assumed, or is it frequently observed simply because a global perspective is often dominant? If affect serves as information about the value of currently accessible inclinations, and a global focus is generally the default perspective, then the global focus of positive affect and local focus of negative affect might be variable rather than fixed. Two experiments tested this hypothesis using different mood inductions, different tests of global–local focus, and different methods of inducing global and local perspectives. In each, we discovered that positive affect empowered whatever focus was momentarily dominant. Thus, whether individuals in happy moods saw the forest or the trees depended only on which of the two had been primed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
104.
According to the Water Authority of Israel, Israel's water economy is on the brink of a crisis. Demands are increasing, exceeding the capacity of the natural sources, which are being depleted. Water, as a resource in short supply, necessitated administrative actions in order to attain its efficient utilization, in accordance with the goals set by the state. In addition, the issue of water allocation in Israel is strongly connected to internal politics and not necessarily to a clear overall policy. This article presents a simulation model which examined a large number of different scenarios and returns the possible outcomes of water allocations in a routine situation of uncertainty. The findings show that even under ideal conditions, a water shortage in Israel is inevitable and urban consumption will demand the largest allocation of water. As a result, the Israeli rural sector will be required to reorganize the water allocation system and production structure. 相似文献
105.
Maximum Likelihood Localization of a Diffusive Point Source Using Binary Observations 总被引:1,自引:0,他引:1
Saravanan Vijayakumaran Yoav Levinbook Tan F. Wong 《Signal Processing, IEEE Transactions on》2007,55(2):665-676
In this paper, we investigate the problem of localization of a diffusive point source of gas based on binary observations provided by a distributed chemical sensor network. We motivate the use of the maximum likelihood (ML) estimator for this scenario by proving that it is consistent and asymptotically efficient, when the density of the sensors becomes infinite. We utilize two different estimation approaches, ML estimation based on all the observations (i.e., batch processing) and approximate ML estimation using only new observations and the previous estimate (i.e., real time processing). The performance of these estimators is compared with theoretical bounds and is shown to achieve excellent performance, even with a finite number of sensors 相似文献
106.
107.
Examined configurality in expert and layperson multiattribute judgments in the domain of child abuse. Important differences were found in the configural rules used by the 2 groups. Laypersons were disjunctive in both assessing risk of abuse and recommending intervention, but their disjunctivity in recommending intervention may have been entirely mediated by prior risk judgments. Experts were less disjunctive in assessing risk and were conjunctive in recommending intervention. These differences are explained in terms of dissimilarities in the underlying theories that experts and laypersons hold about the relationships between attributes and appropriate judgment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
108.
Rideout W. Eichen E. Schlafer J. Lacourse J. Meland E. 《Photonics Technology Letters, IEEE》1989,1(12):438-440
The spontaneous noise spectrum of high-gain semiconductor optical amplifiers is normally assumed to be dominated by spontaneous-spontaneous and signal-spontaneous beat noise, which is white over the frequency range important to fiber-optic systems. Recent measurements have shown that a strong resonance peak in the spontaneous noise spectrum appears well below the threshold current, indicating the existence of relative intensity noise. This noise term has important implications for system design, and its effect on several transmission systems is described. Relative intensity noise in semiconductor optical amplifiers is compared to the similar relative intensity noise found in semiconductor lasers 相似文献
109.
A simple two-parameter model of the monthly demand for natural gas for space heating is developed. First, a simple indicator of the coldness of the month labeled “modified degree days” is presented. Both aggregate monthly demand and monthly demand for a single unit are modeled as a function of this indicator. The model has two parameters, a reference temperature which reflects the internal temperature and free heat contribution and a slope parameter which reflects the thermal behavior of the dwelling. Variation in these two parameters is related to characteristics of the dwelling. Finally, the effect of the onset of the energy crisis on the two parameters is assessed. 相似文献
110.
Shira Engelberg Yuexi Lin Yehuda G. Assaraf Yoav D. Livney 《International journal of molecular sciences》2021,22(3)
Selectively targeted drug delivery systems are preferable chemotherapeutic platforms, as they specifically deliver the drug cargo into tumor cells, while minimizing untoward toxic effects. However, these delivery systems suffer from insufficient encapsulation efficiency (EE), encapsulation capacity (EC), and premature drug release. Herein, we coencapsulated paclitaxel (PTX) and Jasmine oil (JO) within PEG-PCL nanoparticles (NPs), with an average diameter < 50 nm, selectively targeted to non-small cell lung cancer (NSCLC) cells, via S15-aptamer (APT) decoration. JO was selected as an “adhesive” oily core to enhance PTX entrapment, as JO and PTX share similar hydrophobicity and terpenoid structure. JO markedly enhanced EE of PTX from 23% to 87.8% and EC from 35 ± 6 to 74 ± 8 µg PTX/mg PEG-PCL. JO also markedly increased the residual amount of PTX after 69 h, from 18.3% to 65%. Moreover, PTX cytotoxicity against human NSCLC A549 cells was significantly enhanced due to the co-encapsulation with JO; the IC50 value for PTX encapsulated within JO-containing APT-NPs was 20-fold lower than that for APT-NPs lacking JO. Remarkably, JO-containing APT-NPs displayed a 6-fold more potent cell-killing, relatively to the free-drug. Collectively, these findings reveal a marked synergistic contribution of JO to the cytotoxic activity of APT-NP-based systems, for targeted PTX delivery against NSCLC, which may be readily applied to various hydrophobic chemotherapeutics. 相似文献