全文获取类型
收费全文 | 6382篇 |
免费 | 70篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 45篇 |
综合类 | 2篇 |
化学工业 | 691篇 |
金属工艺 | 79篇 |
机械仪表 | 108篇 |
建筑科学 | 148篇 |
矿业工程 | 28篇 |
能源动力 | 74篇 |
轻工业 | 414篇 |
水利工程 | 41篇 |
石油天然气 | 9篇 |
无线电 | 344篇 |
一般工业技术 | 566篇 |
冶金工业 | 3380篇 |
原子能技术 | 49篇 |
自动化技术 | 480篇 |
出版年
2021年 | 35篇 |
2020年 | 23篇 |
2019年 | 29篇 |
2018年 | 44篇 |
2017年 | 43篇 |
2016年 | 38篇 |
2015年 | 34篇 |
2014年 | 46篇 |
2013年 | 216篇 |
2012年 | 116篇 |
2011年 | 138篇 |
2010年 | 133篇 |
2009年 | 117篇 |
2008年 | 162篇 |
2007年 | 158篇 |
2006年 | 134篇 |
2005年 | 153篇 |
2004年 | 118篇 |
2003年 | 134篇 |
2002年 | 104篇 |
2001年 | 80篇 |
2000年 | 87篇 |
1999年 | 197篇 |
1998年 | 941篇 |
1997年 | 504篇 |
1996年 | 389篇 |
1995年 | 234篇 |
1994年 | 204篇 |
1993年 | 225篇 |
1992年 | 75篇 |
1991年 | 69篇 |
1990年 | 84篇 |
1989年 | 81篇 |
1988年 | 92篇 |
1987年 | 72篇 |
1986年 | 62篇 |
1985年 | 67篇 |
1984年 | 51篇 |
1983年 | 61篇 |
1982年 | 67篇 |
1981年 | 51篇 |
1980年 | 49篇 |
1979年 | 42篇 |
1978年 | 52篇 |
1977年 | 91篇 |
1976年 | 183篇 |
1975年 | 41篇 |
1974年 | 34篇 |
1973年 | 51篇 |
1971年 | 27篇 |
排序方式: 共有6458条查询结果,搜索用时 500 毫秒
81.
Y. D. Zhu G. C. Allen J. M. Adams D. Gittins M. Herrero P. Benito P. J. Heard 《应用聚合物科学杂志》2008,108(6):4108-4113
Layered double hydroxides (LDHs), a newly emerging 2D host material, consist of cationic brucite-like layers and exchangeable interlayer anions. In this work, the morphology and dispersion of LDH particles in LDH/Nylon 66 (salt) nanocomposites has been investigated using focused ion beam (FIB) techniques, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The FIB images show that LDHs are present in the polymer phase dispersed to different degrees, with partial intercalation, exfoliation, and aggregation all being observed. The most even dispersion was achieved in nanocomposites with the lowest loading (0.5 wt % LDH). Residual tactoids and agglomerates were most common in the samples made with the highest concentration of LDHs studied here (5 wt %). The dispersion observed using FIB was consistent with TEM and XRD analysis, yet this technique had significant benefits in terms of time and simplicity over these “conventional” technologies. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
82.
Rinkenauer Gerhard; Osman Allen; Ulrich Rolf; Müller-Gethmann Hiltraut; Mattes Stefan 《Canadian Metallurgical Quarterly》2004,133(2):261
Lateralized readiness potentials (LRPs) were used to determine the stage(s) of reaction time (RT) responsible for speed-accuracy trade-offs (SATs). Speeded decisions based on several types of information were examined in 3 experiments, involving, respectively, a line discrimination task, lexical decisions, and an Erikson flanker task. Three levels of SAT were obtained in each experiment by adjusting response deadlines with an adaptive tracking algorithm. Speed stress affected the duration of RT stages both before and after the start of the LRP in all experiments. The latter effect cannot be explained by guessing strategies, by variations in response force, or as an indirect consequence of the pre-LRP effect. Contrary to most models, it suggests that SAT can occur at a late postdecisional stage. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
83.
Sera from 82 cases of leptospirosis (confirmed by micro-agglutination tests or IFAT) and 108 patients with other diseases were investigated using the microcapsule agglutination test (MCAT) for leptospirosis. The overall sensitivity (90.2%), specificity (96.3%), positive predictive value (94.9%), negative predictive value (92.9%), and accuracy of the MCAT (93.7%) were encouraging. MCAT is simple, can be performed by unskilled personnel with minimum laboratory facilities, and produces results in 3 h. MCAT would be a reliable serodiagnostic test for rapidly screening individuals for leptospirosis, in various geographical areas of Thailand. 相似文献
84.
R Kapur BJ Spargo MS Chen JM Calvert AS Rudolph 《Canadian Metallurgical Quarterly》1996,33(4):205-216
A new method is described for producing biomedically relevant polymers with precisely defined micron scale surface texture in the x, y, and z planes. Patterned Si templates were fabricated using photolithography to create a relief pattern in photoresist with lateral dimensions as small as 1 micron. Electroless Ni was selectively deposited in the trenches of the patterned substrate. The Ni served as a resilient mask for transferring the patterns onto the Si substrate to depths of up to 8.5 microns by anisotropic reactive ion etching with a fluorine-based plasma. The 3-dimensional (3-D) textured silicon substrates were used as robust, reusable molds for pattern transfer onto poly (dimethyl siloxane), low density poly (ethylene), poly (L-lactide), and poly (glycolide) by either casting or injection molding. The fidelity of the pattern transfer from the silicon substrates to the polymers was 90 to 95% in all three planes for all polymers for more than 60 transfers from a single wafer, as determined by scanning electron microscopy and atomic force microscopy. Further, the 3-D textured polymers were selectively modified to coat proteins either in the trenches or on the mesas by capillary modification or selective coating techniques. These selectively patterned 3-D polymer substrates may be useful for a variety of biomaterial applications. 相似文献
85.
86.
N Kates M Craven AM Crustolo L Nikolaou C Allen 《Canadian Metallurgical Quarterly》1997,19(5):324-332
The increasingly prominent role of the family physician in delivering mental health care can be enhanced if productive and collaborative relationships can be established with local mental health services. This paper describes a Canadian program that has achieved this by bringing mental health counselors and psychiatrists into the offices of 87 family physicians in 35 practices in a community in Southern Ontario. The paper describes the program, the activities of counselors and psychiatrists within the practices, and the administrative structures set up to coordinate these activities. Data is presented from the evaluation of the first year of the program's operation (13 practices and 45 family physicians) during which time 3085 referrals were received. The program made mental health care more available and accessible, increased continuity of care, provided additional support for the family physician, offered new opportunities for continuing education, and led to a reduced and more efficient use of other mental health services. The components of the program can be adapted to most communities. 相似文献
87.
88.
AL Barry PC Fuchs C Thornsberry JC McLaughlin SG Jenkins DJ Hardy SD Allen 《Canadian Metallurgical Quarterly》1996,15(8):676-678
Three methods approved by the National Committee for Clinical Laboratory Standards for testing the susceptibility of anaerobic bacteria were used to evaluate the fluoroquinolone, trovafloxacin. The methods gave essentially comparable results with 126 anaerobes and with three quality control strains. A collaborative study defined the quality control range for trovafloxacin MICs. Trovafloxacin had good in vitro activity against the more common anaerobes (MIC 90 < = or 2.0 micrograms/ml). 相似文献
89.
90.
The Canadian Armed Forced have been deployed to the republics of the former Yugoslavia since 1992 as part of the United Nations Protection Force and the NATO-led Implementation Force. Most of the combat arms units have been supported by small, self-contained surgical teams for essential surgery. Considerable benefit is gained by cooperating with civilian surgeons. The experience of treating five patients with complicated hydatid disease endemic to the area is examined. Treatment of these patients requires performing major surgical procedures under austere conditions and must be undertaken with care. Careful selection and communication with the surgical nursing team and civilian surgeons is essential. Well selected cases can also pay tremendous dividends in terms of maintaining the skills of personnel who must be prepared for any emergency in addition to providing vital surgical assistance to these patients. 相似文献