首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   44篇
  免费   2篇
电工技术   5篇
化学工业   11篇
轻工业   1篇
无线电   4篇
一般工业技术   4篇
冶金工业   17篇
自动化技术   4篇
  2019年   1篇
  2018年   2篇
  2013年   1篇
  2008年   2篇
  2007年   2篇
  2005年   1篇
  2004年   1篇
  2000年   3篇
  1999年   2篇
  1998年   7篇
  1997年   3篇
  1996年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1990年   2篇
  1989年   1篇
  1987年   1篇
  1985年   1篇
  1984年   3篇
  1981年   1篇
  1976年   2篇
  1966年   1篇
  1964年   1篇
  1935年   1篇
  1934年   1篇
  1933年   1篇
  1932年   1篇
排序方式: 共有46条查询结果,搜索用时 31 毫秒
1.
2.
Psychologists' attitudes and approaches toward the gay, lesbian, and bisexual (GLB) lifestyle continue to change, on the basis of results from 437 responding members of the American Psychological Association. Psychologists are more likely to view an active GLB lifestyle-identity as acceptable and non-pathological, more likely to support and provide gay-affirmative therapy, and much less likely to support changing sexual orientation through psychotherapy. Female psychologists are significantly more likely to view a GLB lifestyle as accepting and to provide gay-affirmative therapy to GLB clients compared with their male counterparts. Finally, training opportunities for psychologists involving GLB issues appear to be increasing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
3.
For the purpose of bimanual control of tetraplegic hands that have useful movement restored by a neuroprosthetic device, the use of myoelectric signals from bilateral sternoclei-domastoid muscles is proposed. Three state control has been proposed where each sternocleidomastoid controls its ipsilateral hand. Demonstration was made with spinal-cord-injured and nonspinal-cord-injured subjects providing three levels of activation that can be repeatably made with each of these muscles. The agonist and antagonist sternocleidomastoids during this command control were differentiated so that the desired hand will respond to a command. Neither normal head movements nor head position within its comfortable range of motion were shown to interfere with the proposed command. The provision of feedback was shown as important to provide robustness in the operation for the users selection of the right or left hand. The performance of spinal cord injured and noninjured persons using this controller was quantitatively measured through the completion of precision tracking tasks by the manipulation of on-screen virtual hands. All subjects were able to operate the controller with a degree of skill acceptable for completion of functional tasks with bilateral stimulated hand grasps. The sensitivity of the subjects performance to variation in controller parameters was also measured.  相似文献   
4.
Optical telemetry has long been an option for transcutaneous data transfer and has been used in various types of implanted systems. This telemetry modality and the efficiency of these optical links are becoming ever more important as higher bandwidth sources such as cortical recording arrays are being implemented in implanted systems. The design of the transmitter-skin-receiver interface (the "optical interface") is paramount to the operation of a transcutaneous optical telemetry link. This interface functions to achieve sufficient receiver signal power for data communication. This paper describes a mathematical analysis and supporting data that quantitatively describes the relationship between the primary interface design parameters. These parameters include the thickness of the skin through which the light is transmitted, the size of the integration area of the optics, the degree of transmitter-receiver misalignment, the efficiency of the optics system, and the emitter power. The particular combination of these parameters chosen for the hardware device will determine the receiver signal power and, therefore, the data quality for the link. This paper demonstrates some of the tradeoffs involved in the selection of these design parameters and provides suggestions for link design. This analysis may also be useful for transcutaneous optical powering systems.  相似文献   
5.
Although protein-based adhesives are eco-friendly, sustainable, and biodegradable, continued improvement in their adhesive performance is desirable. In this work, the effect of adding nanocellulose particles to cottonseed protein-based wood adhesives was studied. Cellulose nanofibers (CNF) were found to be most beneficial at about a 2% additive level, giving 22% improvement in dry adhesive strength over the cottonseed protein control. Cellulose nanocrystals (CNC) were optimal at about 10% additive level, giving 16% strength improvement relative to cottonseed protein alone. The hot water resistance of cottonseed protein isolate was also improved with CNF addition, but not with CNC addition. For comparison, soy protein isolate was also studied and showed about the same relative dry strength improvements with nanocellulose addition, but improvement of hot water resistance was less apparent. Infrared and thermogravimetric analysis suggested that the protein and the nanocellulose were interacting with each other. Thus, CNF may be a useful additive to cottonseed protein formulations used as wood adhesives.  相似文献   
6.
Numerous short‐chain dehydrogenases/reductases (SDRs) have found biocatalytic applications in C=O and C=C (enone) reduction. For NADPH‐dependent C=N reduction, imine reductases (IREDs) have primarily been investigated for extension of the substrate range. Here, we show that SDRs are also suitable for a broad range of imine reductions. The SDR noroxomaritidine reductase (NR) is involved in Amaryllidaceae alkaloid biosynthesis, serving as an enone reductase. We have characterized NR by using a set of typical imine substrates and established that the enzyme is active with all four tested imine compounds (up to 99 % conversion, up to 92 % ee). Remarkably, NR reduced two keto compounds as well, thus highlighting this enzyme family's versatility. Using NR as a template, we have identified an as yet unexplored SDR from the Amaryllidacea Zephyranthes treatiae with imine‐reducing activity (≤95 % ee). Our results encourage the future characterization of SDR family members as a means of discovering new imine‐reducing enzymes.  相似文献   
7.
The association of parental discipline and monitoring with the early conduct problems of 123 boys and girls was assessed in a highly disadvantaged, African American sample. Prospective analyses indicated that, after earlier conduct problems were controlled for, coercive parent discipline and poor parental monitoring at age 4? were independent, reliable predictors of age 6 conduct problems for both boys and girls. The association of parental monitoring with later child conduct problems was mediated, in part, by parents' choice of higher risk schools for their children's kindergarten education. The association of family income with child conduct problems was mediated by parental discipline and monitoring. These models are consistent with previous research on older, European American, more advantaged, male samples, which supports the generality of the association of family processes with child conduct problems across child gender, age, and ethnicity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
8.
Pregnant patients with coccidioidomycosis develop dissemination and serious disease more frequently than do the general population. To assist in prognosis and management, we analyzed the significance of erythema nodosum in pregnant patients with coccidioidomycosis. Sixty-one pregnant patients (mean age +/- SD, 26.4 +/- 6.3 years) were evaluated. Seventy percent of the patients were Hispanic; 15%, African American; 13%, Caucasian; and 2%, unknown race. Of the 30 patients (49%) who developed erythema nodosum, 0 had disseminated disease (P = .001), 1 (3%) with pulmonary involvement required therapy for > 1 year, and 29 (97%) recovered (P = .0008). Of the 31 patients (51%) without erythema nodosum, 11 (35%) had disseminated disease, 12 (39%) required therapy for > 1 year, 17 (55%) recovered, 1 (3%) died, and 1 (3%) had an outcome that was unknown. Erythema nodosum appears to be a salient marker of a positive outcome for pregnant patients, more so than for the general population.  相似文献   
9.
Fatty acid components of fried foods and fats used for frying   总被引:1,自引:0,他引:1  
Oxidation of fat is accelerated at temp as high as those used for frying. The extent of this oxida-tion has been studied by frying two kinds of foods (chicken or potatoes) in cottonseed oil and in lard. Fat samples, taken prior to use and follow-ing 5 and 10 hr of frying (both for chicken and potatoes) were esterified. Subsequent quantita-tive assays of methyl esters by gas chromatogra-phy showed that the linoleic acid content had decreased from 57-49% after cottonseed oil had been used 10 hr for frying. This decrease was present regardless of whether chicken or potatoes were fried. There was no change in the linoleic acid content of lard after chicken was fried, but a decrease from 11.3-5.8% was noted when pota-toes were fried for 10 hr. The fatty acid content of the fat extracted from the potatoes and the fat used to fry them, was the same when sampled at 5 hr. However, at the end of the 10-hr frying period, fat ex-tracted from the potatoes had a lower linoleic acid content than fat used to fry them. Results were the same for both cottonseed oil and lard. Fatty acid components of the fat extracted from the chicken seemed to be affected as much by the fatty acid composition of the chicken itself as by fat used for frying. Whether the chicken was cooked in fat used 5 or 10 hr made little differ-ence. Journal Paper No. 1130, Mississippi Agricultural Experiment Station. A portion of the work in this paper is taken from a thesis sub-mitted in partial fulfillment of the requirements for the Master of Sci-ence degree at Mississippi State University in January, 1963.  相似文献   
10.
In the mouse, the process of implantation is initiated by the attachment reaction between the blastocyst trophectoderm and uterine luminal epithelium that occurs at 2200-2300 h on day 4 (day 1 = vaginal plug) of pregnancy. Several members of the EGF family are considered important in embryo-uterine interactions during implantation. This investigation demonstrates that the expression of two additions to the family, betacellulin and epiregulin, are exquisitely restricted to the mouse uterine luminal epithelium and underlying stroma adjacent to the implanting blastocyst. These genes are not expressed during progesterone-maintained delayed implantation, but are rapidly switched on in the uterus surrounding the implanting blastocyst following termination of the delay by estrogen. These results provide evidence that expression of betacellulin and epiregulin in the uterus requires the presence of an active blastocyst and suggest an involvement of these growth factors in the process of implantation.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号