全文获取类型
收费全文 | 274篇 |
免费 | 28篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 104篇 |
机械仪表 | 1篇 |
建筑科学 | 9篇 |
能源动力 | 3篇 |
轻工业 | 60篇 |
水利工程 | 3篇 |
无线电 | 11篇 |
一般工业技术 | 39篇 |
冶金工业 | 45篇 |
原子能技术 | 1篇 |
自动化技术 | 24篇 |
出版年
2024年 | 2篇 |
2023年 | 12篇 |
2022年 | 25篇 |
2021年 | 26篇 |
2020年 | 8篇 |
2019年 | 14篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 11篇 |
2015年 | 14篇 |
2014年 | 6篇 |
2013年 | 22篇 |
2012年 | 9篇 |
2011年 | 16篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 10篇 |
2007年 | 19篇 |
2006年 | 9篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 3篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 6篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有302条查询结果,搜索用时 15 毫秒
31.
Bove CG De Dea Lindner J Lazzi C Gatti M Neviani E 《International journal of food microbiology》2011,144(3):569-572
Parmigiano Reggiano (PR) is an Italian cooked, long-ripened cheese made with unheated cow's milk and natural whey starter. The microflora is involved in the manufacturing of this cheese, arising from the natural whey starter, the raw milk and the environment. Molecular studies have shown that mesophilic non-starter lactic acid bacteria (NSLAB) are the dominant microflora present during the ripening of PR. In this study, a characterisation of Lactobacillus rhamnosus isolated from a single PR manufacturing and ripening process is reported, using a combination of genotypic fingerprinting techniques (RAPD-PCR and REP-PCR). The intraspecies heterogeneity evidenced for 66 strains is correlated to their abilities to adapt to specific environmental and technological conditions. The detection of biotypes that correlate with specific moments in cheese ripening or differential development throughout this process suggests that these strains may have specific roles closely linked to their peculiar technological properties. 相似文献
32.
Over the past three decades, the achievement of waves of American students with high intellectual potential has declined as a result of inequity in educational treatment. This inequity is the result of an extreme form of egalitarianism within American society and schools, which involves the pitting of equity against excellence rather than promoting both equity and excellence, anti-intellectualism, the "dumbing down" of the curriculum, equating aptitude and achievement testing with elitism, the attraction to fads by schools, and the insistence of schools to teach all students from the same curriculum at the same level. In this article we provide recommendations for creating positive change--recommendations that emphasize excellence for all, that call for responsiveness to individual differences, and that suggest basing educational policies on well-grounded research findings in psychology and education. Educational policies that fail to take into account the vast range of individual differences among students--as do many that are currently in us--are doomed to be ineffective. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
33.
Rosso Ilaria Antonini Massimiliano Galletti Camilla Saracco Guido Specchia Vito 《Topics in Catalysis》2004,30(1-4):475-480
Topics in Catalysis - Ru-based catalysts supported on A zeolites and alumina were synthesised, characterised (XRD, SEM-EDS, TPR) and tested under realistic conditions for the preferential oxidation... 相似文献
34.
In the United States, it is estimated that between 200,000 and 500,000 individuals are culturally Deaf. Deaf culture provides unique challenges that can impact standard therapeutic techniques. Issues regarding the ability of hearing therapists to effectively work with Deaf clients are addressed, and a number of guidelines are offered to assist hearing therapists in bridging language barriers and cultural gaps with Deaf clients. Additionally, concerns about the selection and inclusion of sign language interpreters are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
35.
Pickworth Wallace B.; Rohrer Melissa S.; Fant Reginald V. 《Canadian Metallurgical Quarterly》1997,5(3):235
Some abused drugs have been reported to alter performance on naturalistic tasks such as driving and also on laboratory tasks. The performance effects of several drug classes were examined using a repeated measures design. Eight volunteers were administered 2 doses of ethanol, marijuana, amphetamine, hydromorphone, pentobarbital, or placebo on separate days. The larger dose of each increased subjective drug strength; however, only ethanol and pentobarbital impaired performance on circular lights, digit symbol substitution, and serial math tasks. Both ethanol and pentobarbital impaired performance on card-sorting tasks; impairment was evident at lower doses as the cognitive load increased. Results illustrate differences among drugs in producing performance impairment at doses that cause subjective effects. Increasing cognitive requirements uncovered performance impairment at lower doses. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
36.
37.
38.
Camilla B. Schwind 《International journal of parallel programming》1984,13(5):327-338
The basic idea of our work is to include deductive capabilities in a relational database system by fully using the operands of relational algebra and without using any theorem prover. We present a deductive database system where the user can formulate deduction laws as logical formulas, but which works on an underlying relational database system by fully using the data manipulation routines of such a system. Generally, it is not possible to express the deduction laws by means of expressions of relational algebra (see Ref. 1). In our system, a relational algebra expression is associated with every database deduction law. The result of its evaluation (with respect to an underlying database) is the set of all database entries that can be deduced from the database by applying the respective law once (Theorem 1). By successively applying all these relational expressions for all the database deduction laws it is possible to generate the whole extensional database (i.e. all tuples deducible from the database). 相似文献
39.
Liubov Shtykova Camilla Fant Paul Handa Ann Larsson Kent Berntsson Hans Blanck Roger Simonsson Magnus Nydén Hanna Ingelsten Härelind 《Progress in Organic Coatings》2009
Controlling the release rate of biocides (antifouling agents) from a paint coating is a key issue for the development of multi-season antifouling marine coatings. One promising approach is the use of nanoparticles onto which biocides are adsorbed to prevent premature depletion of the biocide. Adsorption of one novel (Medetomidine) and six commercially available and widely used antifouling biocides (Chlorothalonile, Dichlofluanid, Diuron, Irgarol, Seanine, Tolylfluanid) onto oxide nanoparticles (Al2O3, CuO, MgO, SiO2, TiO2, ZnO) was investigated by HPLC and NMR in different organic solvents. Large differences in adsorption strength depending on the type of nanoparticle and solvent employed were observed. It was shown that nanoparticles coordinate preferentially with the imidazole moiety of Medetomidine. Independent of the type of particle this interaction was considerably stronger in comparison to the other biocides. However, the interaction strength was strongly dependant on the type of solvent, where the largest strongest interaction was achieved in o-xylene. In addition field tests were performed where a considerable decrease in release rate was displayed from coatings containing Medetomidine adsorbed to nanoparticles compared to coatings containing Medetomidine as single additive. 相似文献
40.
Camilla Chua Soo Leng Badlishah Sham Baharin Yaakob Che Man Chin Ping Tan 《Journal of the science of food and agriculture》2008,88(9):1512-1517
BACKGROUND: Squalene was concentrated from palm fatty acid distillate (PFAD) in this study using commercial immobilised Candida antarctica lipase (Novozyme 435®). The PFAD was neutralised (NPFAD) using an alkali to liberate the free fatty acids and then hydrolysed at 65 ± 1 °C. The enzymatic hydrolysis on NPFAD was optimised using response surface methodology (RSM) before being neutralised again to obtain a concentrated squalene fraction. RESULTS: A five‐level, three‐factor central composite rotatable design was adopted to evaluate the effects of the enzymatic hydrolysis parameters reaction time (4–12 h), water content (50–70% w/w) and enzyme concentration (1.5–3.5% w/w) on the percentage yield of squalene concentration. The optimal reaction parameters for maximum yield of squalene concentration were identified from the respective contour plots. The optimal enzymatic hydrolysis conditions were a reaction time of 7.05 h, a water content of 61.40% w/w and an enzyme concentration of 2.23% w/w. CONCLUSION: RSM was used to determine the optimal conditions for enzymatic hydrolysis of NPFAD with C. antarctica lipase for maximum recovery of squalene which could be implemented on an industrial scale. Copyright © 2008 Society of Chemical Industry 相似文献