全文获取类型
收费全文 | 305篇 |
免费 | 24篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 96篇 |
金属工艺 | 4篇 |
机械仪表 | 9篇 |
建筑科学 | 13篇 |
能源动力 | 6篇 |
轻工业 | 46篇 |
无线电 | 29篇 |
一般工业技术 | 68篇 |
冶金工业 | 25篇 |
自动化技术 | 31篇 |
出版年
2024年 | 2篇 |
2023年 | 9篇 |
2022年 | 13篇 |
2021年 | 27篇 |
2020年 | 15篇 |
2019年 | 8篇 |
2018年 | 11篇 |
2017年 | 13篇 |
2016年 | 14篇 |
2015年 | 19篇 |
2014年 | 16篇 |
2013年 | 14篇 |
2012年 | 18篇 |
2011年 | 29篇 |
2010年 | 11篇 |
2009年 | 8篇 |
2008年 | 14篇 |
2007年 | 10篇 |
2006年 | 5篇 |
2005年 | 14篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 3篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有329条查询结果,搜索用时 15 毫秒
1.
Deniz Caylioglu Rieke Johanna Meyer Dana Hellmold Carolin Kubelt Michael Synowitz Janka Held-Feindt 《International journal of molecular sciences》2021,22(7)
Glioblastoma (GBM) is a barely treatable disease due to its profound chemoresistance. A distinct inter- and intratumoral heterogeneity reflected by specialized microenvironmental niches and different tumor cell subpopulations allows GBMs to evade therapy regimens. Thus, there is an urgent need to develop alternative treatment strategies. A promising candidate for the treatment of GBMs is AT101, the R(-) enantiomer of gossypol. The present study evaluates the effects of AT101, alone or in combination with temozolomide (TMZ), in a microenvironmental glioma stem cell niche model of two GBM cell lines (U251MG and U87MG). AT101 was found to induce strong cytotoxic effects on U251MG and U87MG stem-like cells in comparison to the respective native cells. Moreover, a higher sensitivity against treatment with AT101 was observed upon incubation of native cells with a stem-like cell-conditioned medium. This higher sensitivity was reflected by a specific inhibitory influence on the p-p42/44 signaling pathway. Further, the expression of CXCR7 and the interleukin-6 receptor was significantly regulated upon these stimulatory conditions. Since tumor stem-like cells are known to mediate the development of tumor recurrences and were observed to strongly respond to the AT101 treatment, this might represent a promising approach to prevent the development of GBM recurrences. 相似文献
2.
3.
Karin Metz Stephanie Fl?ter Christoph Kr?ger Carolin Donath Daniela Piontek Sabine Gradl 《Nicotine & tobacco research》2007,9(8):853-863
Smokers with smoking-related diseases who are hospitalized in rehabilitation centers should be offered smoking cessation. This is the first study evaluating whether telephone booster sessions after intensive inpatient treatment are an effective strategy. The present study was conducted in 13 rehabilitation centers for somatic disorders as a prospective multicenter study with a randomized treatment-control group design. We compared abstinence rates after hospital discharge from treatment that included a group smoking cessation program with (treatment group) and without telephone booster sessions (control group). Data from 290 smokers were analyzed. After 6 and 12 months the treatment group achieved abstinence rates twice as high as those of the control group. Men profited more from telephone booster sessions than did women. Results indicated that telephone booster sessions were highly effective (even) after an inherently intensive group program during a hospital stay. Further research should focus on the special needs of women receiving telephone counseling. 相似文献
4.
PURPOSE: Cardiopulmonary bypass (CPB) is characterized by translocation of intestinal endotoxin and subsequent endogenous production of the pro-inflammatory cytokine interleukin-6 (IL-6). Plasma lipid fractions, especially high density lipoproteins, bind and neutralize endotoxin and, therefore, inhibit endotoxin-induced macrophage cytokine production, including IL-6. Increased IL-6 plasma levels have been implicated in adverse consequences associated with CPB. Previous studies demonstrated large interpatient variability in IL-6 plasma levels after CPB. The purpose of this study was to evaluate the relationship between plasma lipid concentrations and the concentrations of IL-6 following CPB in humans. METHODS: In a prospective study, a group of 15 patients selected to exclude variables known to influence post-CPB plasma levels of IL-6 (preoperative left ventricular ejection fraction > 45%, similar durations of aortic cross clamping and total CPB time, similar temperature control during CPB, and avoidance of platelet transfusion and shed mediastinal blood re-infusion), IL-6 was measured at baseline, one and 24 hr post-CPB. RESULTS: Interleukin-6 plasma concentrations (mean +/- SD) increased at one (142 +/- 89 pg.ml-1, P < 0.05) and 24 (129 +/- 82 pg.ml-1, P < 0.05) hr post-CPB compared with baseline (1.5 +/- 1 pg.ml-1) concentrations. An inverse correlation was found between IL-6 plasma concentrations at one hour post-CPB and plasma cholesterol concentrations (r = -0.592, P = 0.02), high density lipoprotein (r = -0.595, P = 0.02), and low density lipoprotein (r = -0.656, P = 0.01). CONCLUSIONS: These results suggest that plasma lipids attenuate the production of IL-6 during CPB and may partly explain the variability of interpatient levels of IL-6 reported post-CPB by others. 相似文献
5.
Stella Clarke Gerhard Schillhuber Michael F. Zaeh Heinz Ulbrich 《Multimedia Systems》2008,13(4):253-261
The remote nature of telepresence scenarios can be seen as a strongpoint and also as a weakness. Although it enables the remote
control of robots in dangerous or inaccessible environments, it necessarily involves some kind of communication mechanism
for the transmission of control signals. This communication mechanism necessarily involves adverse network effects such as
delay. Three mechanisms aimed at improving the effects of network delay are presented in this paper: (1) Motion prediction
to partially compensate for network delays, (2) force prediction to learn a local force model, thereby reducing dependency
on delayed force signals, and (3) haptic data compression to reduce the required bandwidth of high frequency data. The utilized
motion prediction scheme was shown to improve operator performance, but had no influence on operator immersion. The force
prediction provided haptic feedback through synchronous forces from the local model, thereby stabilizing the control loop.
The developed haptic data compression scheme reduced the number of packets sent across the network by 90%, while improving
the quality of the haptic feedback. 相似文献
6.
Klara Suchan Justus Just Pascal Beblo Carolin Rehermann Aboma Merdasa Roland Mainz Ivan G. Scheblykin Eva Unger 《Advanced functional materials》2023,33(3):2206047
Photo- and charge-carrier-induced ion migration is a major challenge when utilizing metal halide perovskite semiconductors for optoelectronic applications. For mixed iodide/bromide perovskites, the compositional instability due to light- or electrical bias induced phase-segregation restricts the exploitation of the entire bandgap range. Previous experimental and theoretical work suggests that excited states or charge carriers trigger the process, but the exact mechanism is still under debate. To identify the mechanism and cause of light-induced phase-segregation phenomena, the full compositional range of methylammonium lead bromide/iodide samples are investigated, MAPb(BrxI1-x)3 with x = 0…1, by simultaneous in situ X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy during illumination. The quantitative comparison of composition-dependent in situ XRD and PL shows that at excitation densities of 1 sun, only the initial stage of photo-segregation is rationalized with the previously established thermodynamic models. However, a progression of the phase segregation is observed that is rationalized by considering long-lived accumulative photo-induced material alterations. It is suggested that (additional) photo-induced defects, possibly halide vacancies and interstitials, need to be considered to fully rationalize light-induced phase segregation and anticipate the findings to provide crucial insight for the development of more sophisticated models. 相似文献
7.
We present a robust optimization framework that is applicable to general nonlinear programs (NLP) with uncertain parameters. We focus on design problems with partial differential equations (PDE), which involve high computational cost. Our framework addresses the uncertainty with a deterministic worst-case approach. Since the resulting min–max problem is computationally intractable, we propose an approximate robust formulation that employs quadratic models of the involved functions that can be handled efficiently with standard NLP solvers. We outline numerical methods to build the quadratic models, compute their derivatives, and deal with high-dimensional uncertainties. We apply the presented approach to the parametrized shape optimization of systems that are governed by different kinds of PDE and present numerical results. 相似文献
8.
Jan Tobias Krüger Kay-Peter Hoyer Anatolii Andreiev Mirko Schaper Carolin Zinn 《Advanced Engineering Materials》2023,25(3):2201008
In medical technology, implants are used to improve the quality of patients’ lives. The development of materials with adapted properties can further increase the benefit of implants. If implants are only needed temporarily, biodegradable materials are beneficial. In this context, iron-based materials are promising due to their biocompatibility and mechanical properties, but the degradation rate needs to be accelerated. Apart from alloying, the creation of noble phases to cause anodic dissolution of the iron-based matrix is promising. Due to its high electrochemical potential, immiscibility with iron, biocompatibility, and antibacterial properties, silver is suited for the creation of such phases. A suitable technology for processing immiscible material combinations is powder-bed-based procedure like laser beam melting. This procedure offers short exposure times to high temperatures and therefore a limited time for diffusion of alloying elements. As the silver phases remain after the dissolution of the iron matrix, a modification is needed to ensure their degradability. Following this strategy, pure iron with 5 wt% of a degradable silver–calcium–lanthanum alloy is processed via laser beam melting. Investigation of the microstructure yields achievement of the intended microstructure and long-term degradation tests indicates an impact on the degradation, but no increased degradation rate. 相似文献
9.
Andreas Förner Jan Vollhüter Anna Krapf Abdullah Jamjoom Daniel Hausmann Benjamin Wahlmann Zongwen Fu Carolin Körner Steffen Neumeier Mathias Göken 《Advanced Engineering Materials》2023,25(15):2300407
By increasing the density of interfaces in NiAl–CrMo in situ composites, the mechanical properties can be significantly improved compared to conventionally cast material. The refined microstructure is achieved by manufacturing through electron beam powder bed fusion (PBF-EB). By varying the process parameters, an equiaxed or columnar cell morphology can be obtained, exhibiting a plate-like or an interconnected network of the (Cr,Mo) reinforcement phase which is embedded in a NiAl matrix. The microstructure of the different cell morphologies is investigated in detail using scanning electron microscope, transmission electron microscopy, and atom probe tomography. For both morphologies, the mechanical properties at elevated temperatures are analyzed by compression and creep experiments parallel and perpendicular to the building direction. In comparison to cast NiAl and NiAl–(Cr, Mo), the yield strength of the PBF-EB fabricated specimens is significantly improved at temperatures up to 1,027 °C. While the columnar morphology exhibits the best improved mechanical properties at high temperatures, the equiaxial morphology shows nearly ideal isotropic mechanical behavior, which is a substantial advantage over directionally solidified material. 相似文献
10.
The need for structural rehabilitation of concrete structures all over the world is well known. Extensive amounts of research have been carried out and are ongoing in this field. Most of the laboratory research has been undertaken on structural elements without live load during the strengthening process. Normally owners of structures want to continue their activity or service during strengthening. Full-scale applications have shown that this is possible, but there is a lack of understanding as to how cyclic loads are distributed during strengthening; for example, traffic loads affect the final strengthening result. This paper presents laboratory tests on concrete beams strengthened with carbon fiber-reinforced polymer laminates and near-surface mounted reinforcement. The beams were subjected to a cyclic load during setting of the adhesive, and after additional hardening were then loaded by deformation control up to failure. 相似文献