全文获取类型
收费全文 | 7386篇 |
免费 | 337篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 74篇 |
综合类 | 10篇 |
化学工业 | 1828篇 |
金属工艺 | 171篇 |
机械仪表 | 197篇 |
建筑科学 | 264篇 |
矿业工程 | 13篇 |
能源动力 | 426篇 |
轻工业 | 926篇 |
水利工程 | 41篇 |
石油天然气 | 21篇 |
武器工业 | 1篇 |
无线电 | 360篇 |
一般工业技术 | 1196篇 |
冶金工业 | 931篇 |
原子能技术 | 113篇 |
自动化技术 | 1160篇 |
出版年
2024年 | 22篇 |
2023年 | 76篇 |
2022年 | 181篇 |
2021年 | 268篇 |
2020年 | 179篇 |
2019年 | 156篇 |
2018年 | 338篇 |
2017年 | 319篇 |
2016年 | 352篇 |
2015年 | 236篇 |
2014年 | 306篇 |
2013年 | 697篇 |
2012年 | 439篇 |
2011年 | 493篇 |
2010年 | 416篇 |
2009年 | 414篇 |
2008年 | 308篇 |
2007年 | 296篇 |
2006年 | 222篇 |
2005年 | 157篇 |
2004年 | 110篇 |
2003年 | 120篇 |
2002年 | 96篇 |
2001年 | 71篇 |
2000年 | 68篇 |
1999年 | 58篇 |
1998年 | 245篇 |
1997年 | 171篇 |
1996年 | 110篇 |
1995年 | 69篇 |
1994年 | 76篇 |
1993年 | 77篇 |
1992年 | 34篇 |
1991年 | 21篇 |
1990年 | 28篇 |
1989年 | 26篇 |
1988年 | 24篇 |
1987年 | 19篇 |
1986年 | 17篇 |
1985年 | 28篇 |
1984年 | 29篇 |
1983年 | 15篇 |
1982年 | 18篇 |
1981年 | 35篇 |
1980年 | 17篇 |
1979年 | 24篇 |
1977年 | 39篇 |
1976年 | 55篇 |
1975年 | 17篇 |
1973年 | 19篇 |
排序方式: 共有7732条查询结果,搜索用时 15 毫秒
51.
Optical Properties of Self‐Assembled Cellulose Nanocrystals Films Suspended at Planar–Symmetrical Interfaces 下载免费PDF全文
Blaise L. Tardy Mariko Ago Jiaqi Guo Maryam Borghei Tero Kämäräinen Orlando J. Rojas 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(47)
Hierarchically structured materials comprising rod‐like, chiral, nanoparticles are commonly encountered in nature as they can form assemblies with exceptional optical and mechanical characteristics. These include cellulose nanocrystals (CNCs), which have a large potential for the fabrication of bioinspired materials mimicking those advanced properties. Fine‐tuning the optomechanical properties of assemblies obtained from CNCs hinges on the transformations from suspensions of liquid crystals to long‐range order in the dry state. So far, associated transitions have been studied using trivial interfaces such as planar substrates. Such transitions are explored as they evolve onto meshed supports. The meshed substrate offers a complex topology, as is encountered in nature, for the formation of CNCs films. The CNCs self‐assembly occurs under confinement and support of the framework bounding the mesh openings. This leads to coexisting suspended and supported nanoparticle layers exhibiting nematic and/or chiral nematic order. Optical microscopy combined with crossed polarizers indicate that the formation of the suspended films occurs via intermediate gelation or kinetic arrest of CNCs across the mesh's open areas. The formation of self‐standing, ultrathin films of CNCs with tunable optical properties, such as selective reflections in the visible range (structural color), is demonstrated by using the presented simple and scalable approach. 相似文献
52.
53.
Unraveling Unprecedented Charge Carrier Mobility through Structure Property Relationship of Four Isomers of Didodecyl[1]benzothieno[3,2‐b][1]benzothiophene 下载免费PDF全文
Yusuke Tsutsui Guillaume Schweicher Basab Chattopadhyay Tsuneaki Sakurai Jean‐Baptiste Arlin Christian Ruzié Almaz Aliev Artur Ciesielski Alan R. Kennedy Vincent Lemaur Yoann Olivier Rachid Hadji Lionel Sanguinet Frédéric Castet Silvio Osella Dmytro Dudenko David Beljonne Jérôme Cornil Paolo Samorì Shu Seki Yves H. Geerts 《Advanced materials (Deerfield Beach, Fla.)》2016,28(33):7106-7114
54.
55.
Péter Böröcz Csaba Pánczél Kyle Dunno S. Paul Singh 《Packaging Technology and Science》2023,36(1):45-53
This study investigates longitudinal acceleration events during freight transportation characterized as low-acceleration and long-duration using delivery van type vehicles. In the past several decades, there has been an increase in shipments requiring only single or small pallet load quantities and mixed palletized unit loads comprised of different goods. These loads are often transported in delivery vans without load securing devices, increasing the risk of product loss and damage due to load failures resulting from unit loads shifting. A field data acquisition system was used to observe and record the random acceleration events from five vehicles for 5 days, explicitly targeting the vehicles' braking and acceleration manoeuvres. The study aimed to understand the physical phenomenon and provide new information that can be used during preshipment tests to prevent damage to goods and ensure unit load integrity is maintained throughout the supply chain. The events were statistically analysed to understand their probability of occurrence, severity level, and quantify critical parameters such as event rise and hold times. For the braking manoeuvre, the statistical mean of average deceleration was 0.25 g with a corresponding rise and hold duration of 0.83 and 1.27 s, respectively. During the vehicle's acceleration manoeuvre, the statistical mean of average acceleration was 0.29 g with a rise and hold time of 1.29 and 1.39 s, respectively. Utilizing the field data, composite profiles were developed, and these profiles were compared to the currently available test procedures and previous results of other studies. 相似文献
56.
FM Akgür T Ozdemir M Olguner S Erbayraktar E Ozer T Aktu? 《Canadian Metallurgical Quarterly》1998,33(8):1317-1319
Like umblical enteric remnants (eg, umblical sinus and omphalomesenteric fistula), enteric remnants can be seen on the dorsal aspect of the body (dorsal enteric sinus, dorsal enteric fistula IDEF], dorsal enteric diverticulum) in conjunction with complete cleft of the vertebral column. Complete cleft of the vertebral column associated with gastrointestinal tract and central nervous system anomalies is known as "split notochord syndrome" (SNS). The authors present an unreported variant of SNS having dorsal enteric diverticulum adjacent to the DEF. The patient died 17 days after surgical repair. 相似文献
57.
Holmér AK 《Applied optics》1996,35(15):2614-2618
A kinoform is used to split the beam of a Nd:YAG laser into six beams. The laser beams are, by means of optical fibers and collimating-focusing optics, transferred to the surface to be machined. Thus multiple grooves can be machined simultaneously. For demonstration, 100-μm-wide grooves are simultaneously machined into a SnO(2) thin film deposited on a glass substrate. The resulting grooves are well isolated. This result shows that the technique could be used, for example, in solar cell manufacturing to increase the efficiency of laser scribing. 相似文献
58.
E Huidovici M Artino R Carmaciu A B?d?r?u A Iancu 《Canadian Metallurgical Quarterly》1996,100(3-4):135-137
Our previous experimental studies on rats motionless for 7 to 60 days in special devices limiting their movements revealed a significantly increased activity of the fibrinolytic system (Groza, Artino) due to the "detention stress" rather then to the immobilization. Starting from these studies we have tried to observe the behaviour of the fibrinolytic system during long-term orthopedic immobilization (7-28 days) on patients having different injuries of the lower limb and submitted to orthopedic therapy (with or without osteosynthesis) to which an anticoagulant preventive treatment was added (heparin or low-molecular-weight substitutes such as Clivarine, Fraxiparine). We studied on 23 patients (11 male and 12 female) motionless for 14, 21, 28 days the plasma fibrinolytic activity (PFA) through euglobulin lysis time (ELT). Clinical investigation revealed that PFA did not change significantly during long-term orthopedic immobilization regardless of the duration of immobilization (14,21,28 days). Rosenfeld et al. (1994) described in healthy volunteers on bedrest for 36 hours an increase of PFA beginning at 24 hours of immobilization, this variation being capable of preventing stasis effects. Our results suggest that preventive anticoagulant therapy properly given during immobilization prevents thromboembolic events. 相似文献
59.
The Graphics Processing Unit (GPU) is a powerful tool for parallel computing. In the past years the performance and capabilities of GPUs have increased, and the Compute Unified Device Architecture (CUDA) - a parallel computing architecture - has been developed by NVIDIA to utilize this performance in general purpose computations. Here we show for the first time a possible application of GPU for environmental studies serving as a basement for decision making strategies. A stochastic Lagrangian particle model has been developed on CUDA to estimate the transport and the transformation of the radionuclides from a single point source during an accidental release. Our results show that parallel implementation achieves typical acceleration values in the order of 80-120 times compared to CPU using a single-threaded implementation on a 2.33 GHz desktop computer. Only very small differences have been found between the results obtained from GPU and CPU simulations, which are comparable with the effect of stochastic transport phenomena in atmosphere. The relatively high speedup with no additional costs to maintain this parallel architecture could result in a wide usage of GPU for diversified environmental applications in the near future. 相似文献
60.
Vladim?´r Janiš 《Information Sciences》2010,180(7):1134-1137
We consider the system of intuitionistic fuzzy sets (IF-sets) in a universe X and study the cuts of an IF-set. Suppose a left continuous triangular norm is given. The t-norm based cut (level set) of an IF-set is defined in a way that binds the membership and nonmembership functions via the triangular norm. This is an extension of usual cuts of IF-sets. We show that the system of these cuts fulfils analogical properties as usual systems of cuts. However, it is not possible to reconstruct an IF-set from the system of t-norm based cuts. 相似文献