全文获取类型
收费全文 | 3993篇 |
免费 | 75篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 145篇 |
综合类 | 3篇 |
化学工业 | 751篇 |
金属工艺 | 71篇 |
机械仪表 | 79篇 |
建筑科学 | 72篇 |
矿业工程 | 3篇 |
能源动力 | 122篇 |
轻工业 | 429篇 |
水利工程 | 12篇 |
石油天然气 | 15篇 |
无线电 | 406篇 |
一般工业技术 | 606篇 |
冶金工业 | 1048篇 |
原子能技术 | 83篇 |
自动化技术 | 227篇 |
出版年
2023年 | 26篇 |
2022年 | 42篇 |
2021年 | 60篇 |
2020年 | 32篇 |
2019年 | 32篇 |
2018年 | 42篇 |
2017年 | 50篇 |
2016年 | 56篇 |
2015年 | 39篇 |
2014年 | 79篇 |
2013年 | 179篇 |
2012年 | 134篇 |
2011年 | 145篇 |
2010年 | 124篇 |
2009年 | 119篇 |
2008年 | 173篇 |
2007年 | 169篇 |
2006年 | 136篇 |
2005年 | 91篇 |
2004年 | 92篇 |
2003年 | 111篇 |
2002年 | 78篇 |
2001年 | 94篇 |
2000年 | 87篇 |
1999年 | 136篇 |
1998年 | 399篇 |
1997年 | 211篇 |
1996年 | 165篇 |
1995年 | 104篇 |
1994年 | 106篇 |
1993年 | 112篇 |
1992年 | 70篇 |
1991年 | 51篇 |
1990年 | 42篇 |
1989年 | 32篇 |
1988年 | 36篇 |
1987年 | 29篇 |
1986年 | 33篇 |
1985年 | 34篇 |
1984年 | 35篇 |
1983年 | 37篇 |
1982年 | 23篇 |
1981年 | 32篇 |
1980年 | 23篇 |
1979年 | 24篇 |
1978年 | 26篇 |
1977年 | 21篇 |
1976年 | 51篇 |
1974年 | 9篇 |
1972年 | 10篇 |
排序方式: 共有4072条查询结果,搜索用时 15 毫秒
71.
Subfragment-1 prepared by chymotryptic digestion of myosin was applied to a column of Sepharose-adipic acid hydrazide-ATP in 1 mM EDTA, 10 mM Tris-HCL (PH 7.6), and 40 mM KCL. Ninety-nine per cent of subfragment-1 was adsorbed on the column in this medium. Fourty-three per cent of the applied protein was eluted with 6 mM ADP in the above buffer and then 52% was eluted with 1 mM EDTA, 10 mM Tris-HCL (pH 7.6), AND 0.7 M KCL. The former fraction contained g3 chain and the latter g1 chain. These fractions were apparently the same as the components, p2 and p1, respectively, isolated by ion-exchange chromatography using DEAE-cellulose (Yagi & Otani (1974) J. Biochem. 76, 365-373). No significant difference of ADP binding was found between the two fractions, both could bind about 0.5 mole per 10(5) g of protein. The preparation of the two subfragment-1 fractions is described. 相似文献
72.
M Miyata T Yamamoyo M Yamaguchi K Nakao T Yoshida 《Canadian Metallurgical Quarterly》1976,152(4):540-543
Serial measurements of plasma "true glucagon" (PG) and of glucagon-like immunoreactive materials (GLI) were carried out during and after total resection of the pancreas in a 62-year-old man with calcified pancreatitis. The postoperative course of this patient was uneventful and diabetes was well controlled. PG disappeared from the blood within 30 min after resection of the pancreas. In spite of the evidence that no pancreatic tissue was present in the abdomen, PG was detected again in the blood from 18 hr after total pancreatectomy until the ninth postoperative day. However, plasma PG did not rise following infusion of arginine during the fourteenth postoperative week. After an initial decrease, plasma GLI rose abruptly on the second postoperative day and remained elevated thereafter. The fluctuations of plasma PG and GLI were not parallel. 相似文献
73.
Gerstein Alvin I.; Brodzinsky David M.; Reiskind Naomi 《Canadian Metallurgical Quarterly》1976,44(5):760
Rorschach protocols of 173 7-14 yr old Blacks and Whites who had been evaluated at a child guidance clinic were rescored with respect to developmental level of perceptual integration. Blacks had higher perceptual-integration scores in comparison to Whites. This finding, however, was accounted for by the higher performance of low-IQ (70-89) Blacks as compared to low-IQ Whites. No differences were obtained between average-IQ (90-109) Blacks or Whites. It is suggested that standard IQ tests may not adequately tap the cognitive capacity of some Black children and that use of the Rorschach from a developmental/structural perspective may provide a useful adjunctive measure of intelligence that would more realistically assess children's cognitive competence. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
74.
Anion exchange membranes containing amino groups, insoluble in acidic and alkaline aqueous solutions, were prepared from chitosan, poly(vinyl alcohol), and glutaraldehyde. Using the membrane in a diaphragm cell, one side being adjusted to be acidic and the other alkaline, it was possible to transport actively halogen ions through the membrane from the acidic side to the alkaline side against the concentration gradient between both sides of the membrane. The active transport of halogen ions through the membrane was significantly influenced by the pH difference and electric potential difference between both sides of the membrane. 相似文献
75.
Omid Pourali Feridoun Salak Asghari Hiroyuki Yoshida 《Journal of food engineering》2009,95(3):510-516
Sub-critical water technique was used for simultaneous inactivation of lipase enzyme existing in rice bran and extraction of its oil in order to obtain the stabilized edible rice bran oil. Sub-critical water treatment was carried out in the temperature range between 120 and 240 °C for 10 and/or 20 min residence time in a batch reactor. The quality of the extracted oil was evaluated with respect to its total free fatty acids concentration over a 12 week period, and compared with the oil obtained by conventional extraction methods. Without sub-critical water treatment, the concentration of total free fatty acids in the rice bran significantly increased from 5.6% to 36.0%. In contrast, no increase was observed in the total free fatty acids concentration in the samples treated by sub-critical water. Experimental evidence showed that total free fatty acids concentration increased somewhat in the oils treated by conventional methods. Considering no change was observed in total free fatty acid concentration in the treated oils by sub-critical water, it was found that sub-critical water not only could efficiently extract oil from rice bran in a short residence time but also completely stabilized the extracted oil. Oil extraction yields generally increased with increases in sub-critical water treatment temperature and residence time. The highest extraction yield of oil was 249 (mg/g dry matter) obtained at 240 °C and 10 min residence time. Oil extraction by sub-critical water could be conducted in a very short residence time (10 and/or 20 min). Also, the kinetics of free fatty acids formation in untreated rice bran was investigated and developed which successfully describes the concentration of total free fatty acids in the course of rice bran storage. 相似文献
76.
Role of Heavy Meromyosin in Heat‐Induced Gelation in Low Ionic Strength Solution Containing l‐Histidine 下载免费PDF全文
Toru Hayakawa Yuri Yoshida Masanori Yasui Toshiaki Ito Jun‐ichi Wakamatsu Akihito Hattori Takanori Nishimura 《Journal of food science》2015,80(8):C1641-C1645
The gelation of myosin has a very important role in meat products. We have already shown that myosin in low ionic strength solution containing l ‐histidine forms a transparent gel after heating. To clarify the mechanism of this unique gelation, we investigated the changes in the nature of myosin subfragments during heating in solutions with low and high ionic strengths with and without l ‐histidine. The hydrophobicity of myosin and heavy meromyosin (HMM) in low ionic strength solution containing l ‐histidine was lower than in high ionic strength solution. The SH contents of myosin and HMM in low ionic strength solution containing l ‐histidine did not change during the heating process, whereas in high ionic strength solution they decreased slightly. The heat‐induced globular masses of HMM in low ionic strength solution containing l ‐histidine were smaller than those in high ionic strength solution. These findings suggested that the polymerization of HMM molecules by heating was suppressed in low ionic strength solution containing l ‐histidine, resulting in formation of the unique gel. 相似文献
77.
78.
79.
80.