全文获取类型
收费全文 | 2458篇 |
免费 | 166篇 |
国内免费 | 3篇 |
学科分类
工业技术 | 2627篇 |
出版年
2024年 | 4篇 |
2023年 | 31篇 |
2022年 | 61篇 |
2021年 | 132篇 |
2020年 | 80篇 |
2019年 | 82篇 |
2018年 | 100篇 |
2017年 | 84篇 |
2016年 | 103篇 |
2015年 | 88篇 |
2014年 | 116篇 |
2013年 | 189篇 |
2012年 | 142篇 |
2011年 | 225篇 |
2010年 | 141篇 |
2009年 | 136篇 |
2008年 | 172篇 |
2007年 | 118篇 |
2006年 | 107篇 |
2005年 | 71篇 |
2004年 | 49篇 |
2003年 | 56篇 |
2002年 | 37篇 |
2001年 | 28篇 |
2000年 | 31篇 |
1999年 | 23篇 |
1998年 | 50篇 |
1997年 | 45篇 |
1996年 | 28篇 |
1995年 | 18篇 |
1994年 | 16篇 |
1993年 | 11篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 8篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 2篇 |
排序方式: 共有2627条查询结果,搜索用时 312 毫秒
121.
Andrea Carletto Andrés F. Cardozo Raffaella Suriano Eric Manoury Stefano Turri Rinaldo Poli 《Israel journal of chemistry》2012,52(3-4):328-338
Core cross-linked amphiphilic star-block copolymers were prepared by hydrolysis of the outer shell of star-block copolymers prepared using copper mediated atom transfer radical polymerization (ATRP). In an arm-first approach, linear poly(tert-butyl methacrylate) macroinitiators (PtBMA-Cl) were extended with styrene to yield PtBMA-b-PS-Cl and then cross-linked with divinylbenzene (DVB) in order to yield (PtBMA-b-PS)arms-PDVBcore star-block copolymers. Then, PMAA-b-PS block and (PMAA-PS)arms-PDVBcore star-block copolymers were obtained by hydrolysis of the PtBMA blocks in both linear and cross-linked copolymers, as confirmed by 1H NMR analyses. The amphiphilic character of these copolymers was confirmed by solubilisation in water. Several factors affecting the polymer aggregation and solubility such as the length, the composition of the arms and the catalyst used were studied. An acrylate analogue, that is, (PAA-b-PS)arms-PDVBcore, was also prepared for comparison purposes. Atomic force microscopy (AFM) and differential scanning calorimetry (DSC) were used to elucidate the morphology and the thermal behaviour of the star-block copolymers. 相似文献
122.
Stefano Abbate Marco Avvenuti Francesco Bonatesta Guglielmo Cola Paolo Corsini Alessio Vecchio 《Pervasive and Mobile Computing》2012,8(6):883-899
Falls are a major cause of injuries and hospital admissions among elderly people. Thus, the caregiving process and the quality of life of older adults can be improved by adopting systems for the automatic detection of falls. This paper presents a smartphone-based fall detection system that monitors the movements of patients, recognizes a fall, and automatically sends a request for help to the caregivers. To reduce the problem of false alarms, the system includes novel techniques for the recognition of those activities of daily living that could be erroneously mis-detected as falls (such as sitting on a sofa or lying on a bed). To limit the intrusiveness of the system, a small external sensing unit can also be used for the acquisition of movement data. 相似文献
123.
Filippo Arrichiello Hordur K. Heidarsson Stefano Chiaverini Gaurav S. Sukhatme 《Intelligent Service Robotics》2012,5(1):73-87
We present a study on the cooperative control of two autonomous surface vehicles performing a caging and transport mission
on the water surface. The two vehicles, connected to each other by means of a floating flexible rope, are required to capture
a floating target from a given location, and transport it to a designated position. We focus on the coordination and control
strategy to meet these requirements, and on its implementation on two under-actuated vehicles. We describe a multi-layered
control architecture which achieves the goal, followed by simulation studies and field experiments with the two vehicles caging
and transporting a floating target on the surface of a lake. 相似文献
124.
Christopher J. Stefano 《Rocks & Minerals》2015,90(4):386-387
125.
126.
In this paper we report the results of a study on the corrosion properties of carbon steel (UNI Fe360B) coated with a thin aluminium layer electrodeposited from ionic liquids and subsequently post-treated in an oxidizing environment. Two different types of treatments were investigated: thermal oxidation in air and electrochemical anodization. We found that heat treatments provided only a modest improvement of the anticorrosion properties while the electrochemical treatment produced a significant improvement. 相似文献
127.
Enzo Mangano Daniel Friedrich Stefano Brandani 《American Institute of Chemical Engineers》2015,61(3):981-991
The ideal adsorbed solution (IAS) theory has been shown to predict reliably multicomponent adsorption for both gas and liquid systems. There is a lack of understanding of the conditions which guarantee convergence for various algorithms used to solve the IAS theory equations and inconsistencies are present in the reported computational effort required for the different approaches. The original nested loop and the FastIAS technique are revisited. The resulting system of equations is highly nonlinear but both methods are shown to be robust if appropriate choices are made for the starting values of the unknown variables. New initial conditions are proposed and the resulting algorithms are compared in a consistent manner with the main methods available to solve the IAS theory equations. The algorithms are extended for the first time to all nontype I isotherms. © 2014 American Institute of Chemical Engineers AIChE J, 61: 981–991, 2015 相似文献
128.
Soft X‐ray Ptychographic Imaging and Morphological Quantification of Calcium Silicate Hydrates (C–S–H)
下载免费PDF全文
![点击此处可从《Journal of the American Ceramic Society》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Sungchul Bae Rae Taylor David Shapiro Peter Denes John Joseph Rich Celestre Stefano Marchesini Howard Padmore Tolek Tyliszczak Tony Warwick David Kilcoyne Pierre Levitz Paulo J. M Monteiro 《Journal of the American Ceramic Society》2015,98(12):4090-4095
Morphological details of calcium silicate hydrate (C–S–H) stemming from the hydration process of Portland cement (PC) phases are crucial for understanding the PC‐based systems but are still only partially known. Here we introduce the first soft X‐ray ptychographic imaging of tricalcium silicate (C3S) hydration products. The results are compared using both scanning transmission X‐ray and electron transmission microscopy data. The evidence shows that ptychography is a powerful method to visualize the details of outer and inner product C–S–H of fully hydrated C3S, which have fibrillar and an interglobular structure with average void sizes of 20 nm, respectively. The high‐resolution ptychrography image enables us to perform morphological quantification of C–S–H, and, for the first time, to possibly distinguish the contributions of inner and outer product C–S–H to the small angle scattering of cement paste. The results indicate that the outer product C–S–H is mainly responsible for the q?3 regime, whereas the inner product C–S–H transitions to a q?2 regime. Various hypotheses are discussed to explain these regimes. 相似文献
129.
130.
Influence of plasticizers and cryogenic grinding on the high‐cooling‐rate solidification behavior of PBT/PET blends
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Anesh Manjaly Poulose Stefano Piccarolo Domenico Carbone Saeed M. Al‐Zahrani 《应用聚合物科学杂志》2016,133(10)
Two structurally different plasticizers (cyclic and linear) and the effect of cryogenic grinding on the solidification behavior at high cooling rates by a continuous cooling transformation approach of poly(butylene terephthalate)/poly(ethylene terephthalate), PBT/PET, blends are described. The solidification curve (density versus cooling rate) is confirmed as an effective tool to compare the differences in crystallization behavior under conditions mimicking processing. In comparison to the bulky cyclic plasticizer, the linear oligomeric one was found to have a more pronounced influence on the crystallization behavior. A 60/40 by weight PBT/PET blend shows a drop‐off of density at ~50 K/s. In the plasticized sample, the long‐range crystalline order appears up to a cooling rate of ~250K/s, making the blend comparable to pure PBT. Grinding the components before blending further improves crystallizability and synergy to the addition of the plasticizer. The results suggest the important role of local chain mobility in the solidification behavior at high cooling rates. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43083. 相似文献