全文获取类型
收费全文 | 1738篇 |
免费 | 51篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 51篇 |
综合类 | 20篇 |
化学工业 | 413篇 |
金属工艺 | 23篇 |
机械仪表 | 24篇 |
建筑科学 | 119篇 |
矿业工程 | 11篇 |
能源动力 | 32篇 |
轻工业 | 182篇 |
水利工程 | 24篇 |
石油天然气 | 20篇 |
无线电 | 130篇 |
一般工业技术 | 301篇 |
冶金工业 | 265篇 |
原子能技术 | 17篇 |
自动化技术 | 160篇 |
出版年
2023年 | 18篇 |
2021年 | 24篇 |
2020年 | 20篇 |
2019年 | 20篇 |
2018年 | 24篇 |
2017年 | 16篇 |
2016年 | 21篇 |
2015年 | 31篇 |
2014年 | 41篇 |
2013年 | 92篇 |
2012年 | 63篇 |
2011年 | 90篇 |
2010年 | 53篇 |
2009年 | 66篇 |
2008年 | 71篇 |
2007年 | 71篇 |
2006年 | 61篇 |
2005年 | 48篇 |
2004年 | 53篇 |
2003年 | 33篇 |
2002年 | 40篇 |
2001年 | 19篇 |
2000年 | 28篇 |
1999年 | 21篇 |
1998年 | 30篇 |
1997年 | 26篇 |
1996年 | 17篇 |
1995年 | 25篇 |
1994年 | 21篇 |
1993年 | 20篇 |
1992年 | 19篇 |
1991年 | 30篇 |
1990年 | 23篇 |
1987年 | 23篇 |
1986年 | 19篇 |
1985年 | 27篇 |
1984年 | 28篇 |
1983年 | 22篇 |
1982年 | 28篇 |
1981年 | 21篇 |
1980年 | 21篇 |
1979年 | 17篇 |
1978年 | 23篇 |
1975年 | 19篇 |
1974年 | 27篇 |
1973年 | 20篇 |
1972年 | 26篇 |
1970年 | 20篇 |
1967年 | 14篇 |
1966年 | 15篇 |
排序方式: 共有1792条查询结果,搜索用时 15 毫秒
101.
Alfred Watzl 《产业用纺织品》2008,26(2):47-48
Fleissner的水刺非织造布生产线生产用于揩布产品和医用产品的木浆复合产品,注重于节省原材料成本,降低能耗,保护环境。 相似文献
102.
Cella David; Hughes Chanita; Peterman Amy; Chang Chih-Hung; Peshkin Beth N.; Schwartz Marc D.; Wenzel Lari; Lemke Amy; Marcus Alfred C.; Lerman Caryn 《Canadian Metallurgical Quarterly》2002,21(6):564
The Multidimensional Impact of Cancer Risk Assessment (MICRA) is a new tool to measure the specific impact of result disclosure after genetic testing. The authors compared its performance with that of questionnaires measuring general and cancer-specific distress. Participants (158 women) responded 1 month after they received genetic test results. The women were divided into 4 standard clinical test result groups: BRCA1/2 positive, BRCA1/2 negative, panel negative, and true negative. Factor analysis supported the formation of 3 subscales: Distress (6 items, α= .86), Uncertainty (9 items, α= .77), and Positive Experiences (4 items, α= .75). All 3 MICRA subscales differentiated participants who were BRCAI/2 positive from the other 3 groups. MICRA thus helps identify subgroups of vulnerable genetic testing participants. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
103.
Alfred Saroli 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1987,184(2):122-124
Summary This study showed that the bitterness of dipeptide methyl esters depends on the amino acid sequence and that a N-terminall-phenylalanine residue is more effective than some other amino acid residues with hydrophobic side chains. It was observed that dipeptide benzyl esters were notably more bitter than the corresponding methyl esters and that their bitterness depends on the configuration of the C-terminal amino acid. These results exhibit analogies with those obtained with denatonium chloride derivatives, which suggests that the model of interaction with the bitter receptor previously proposed for denatonium chloride is applicable to dipeptides and their ester derivatives.
Struktur — Aktivitätsbeziehung von bitteren Dipeptidestern
Zusammenfassung Diese Studie zeigt, daß die Schwellenwerte der Bitterkeit von Dipeptidmethylestern von der Aminosäuresequenz abhängt und daß ein N-terminalerl-Phenylalaninrest wirksamer ist als andere Aminosäuren mit hydrophoben Seitenketten. Wir haben beobachtet, daß die Dipeptidbenzylester deutlich bitterer sind als die entsprechenden Methylester und daß die Bitterkeit von der Konfiguration der C-terminalen Aminosäure abhängt. Diese Resultate zeigen Ähnlichkeiten mit denen der Derivate von Denatoniumchlorid, woraus zu schließen ist, daß das für Denatoniumchlorid schon früher vorgeschlagene Modell der Wechselbeziehung mit dem Rezeptor der Bitterkeit auf Dipeptide und ihre Ester anwendbar ist.相似文献
104.
Ju H. Choi Alfred Margaryan Ashot Margaryan Frank G. Shi 《Journal of Materials Science》2008,43(3):1109-1113
The dependence of thermo-mechanical, and mechanical properties on various rare earth dopants (RE) including Nd2O3, Er2O3, and Yb2O3 in 0.4MgF2-0.4BaF2-0.1Ba(PO3)2-0.1Al(PO3)3 glasses (MBBA system) is systematically investigated. MBBA system doped with RE dopants presented the potential application
in the field of communication and high power layer system in the previous reports. In this work, it is found that the density
of the doped glass increases with an increasing of RE concentration, which could be understood in terms of cationic field
strength (CFS) effect. The Knoop hardness is found to decrease with the loading time and dopant concentration due to the indentation
size effect (ISE) effect. The observed decrease of thermal expansion coefficient and the increase of glass transition temperature
T
g with increasing dopant concentration are elucidated in terms of the increasing number of strong covalent bonds with increasing
RE dopant concentration. Those results will be of paramount importance before designing optical devices. 相似文献
105.
Alfred Clark 《Catalysis Reviews》1970,3(1):145-173
There are at least three heterogeneous catalyst systems of interest for low-pressure polymerization of olefins to high polymers: 相似文献
106.
Durch Kombination eines Plasmaspektrometers (ICP) mit einer neuen Apparatur zur elektrothermischen Verdampfung konnte der Gehalt an metallischem Calcium in niedrig legiertem, calciumbehandeltem Stahl bestimmt werden. Die kontrollierte Erwärmung von Stahlspänen auf 2 000°C führt zur vollständigen Verdampfung des elementaren Calciums, während das chemisch gebundene Calcium bei dieser Temperatur nicht verdampft. Das verdampfte Calcium wurde mit Argon in das Plasmaspektrometer transportiert, und das erzeugte Emissionsspektrum wurde zur quantitativen Auswertung genutzt. 相似文献
107.
108.
Teachers of introductory courses in psychology and those who wrote the textbooks for the courses at the start of the 20th century represented the new psychology that replaced the old psychology of mental philosophy. Teachers and texts presented psychology as a natural science of the mind and mental processes, described its methods, and suggested its potential applications to practical concerns. Textbooks and teachers varied in their approaches to psychology, their priorities among its methods, and their emphases on applying psychology. The introductory course in psychology accurately reflected the state of the discipline at the turn of the century. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
109.
We monetize the cost for moving to a culturally different location. We combine administrative social security panel data with a proxy for cultural difference based on historical dialect dissimilarity between German counties. Conditional on geographic distance and pre‐migration wage profiles, we find that migrants demand a (indexed with respect to local rents) wage premium of about 1 (1.5) per cent for overcoming one standard deviation in cultural dissimilarity. The effect is driven by males and those who earn above average occupational wages before migration, and more pronounced for geographically short moves. 相似文献
110.
Bismark Mensah Dinesh Kumar Dong‐Kwon Lim Seung Gyeom Kim Byeong‐Heon Jeong Changwoon Nah 《应用聚合物科学杂志》2015,132(36)
The graphene oxide (GO) was prepared by sonication‐induced exfoliation from graphite oxide, which was produced by oxidation from graphite flakes with a modified Hummer's method. The GO was then treated by hydrazine to obtain reduced graphene oxide (rGO). On the basis of the characterization results, the GO was successfully reduced to rGO. Acrylonitrile–butadiene rubber (NBR)–GO and NBR–rGO composites were prepared via a solution‐mixing method, and their various physical properties were investigated. The NBR–rGO nanocomposite demonstrated a higher curing efficiency and a change in torque compared to the gum and NBR–GO compounds. This agreed well with the crosslinking density measured by swelling. The results manifested in the high hardness (Shore A) and high tensile modulus of the NBR–rGO compounds. For instance, the tensile modulus at a 0.1‐phr rGO loading greatly increased above 83, 114, and 116% at strain levels of 50, 100, and 200%, respectively, compared to the 0.1‐phr GO loaded sample. The observed enhancement was highly attributed to a homogeneous dispersion of rGO within the NBR matrix; this was confirmed by scanning electron microscopy and transmission electron microscopy analysis. However, in view of the high ultimate tensile strength, the NBR–GO compounds exhibited an advantage; this was presumably due to strong hydrogen bonding or polar–polar interactions between the NBR and GO sheets. This interfacial interaction between GO and NBR was supported by the marginal increase in the glass‐transition temperatures of the NBR compounds containing fillers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42457. 相似文献