全文获取类型
收费全文 | 1983篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 16篇 |
金属工艺 | 1篇 |
机械仪表 | 3篇 |
建筑科学 | 1篇 |
轻工业 | 19篇 |
无线电 | 1篇 |
一般工业技术 | 13篇 |
冶金工业 | 1921篇 |
原子能技术 | 1篇 |
自动化技术 | 8篇 |
出版年
2022年 | 1篇 |
2013年 | 7篇 |
2012年 | 2篇 |
2011年 | 5篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 2篇 |
2001年 | 1篇 |
1999年 | 49篇 |
1998年 | 584篇 |
1997年 | 308篇 |
1996年 | 244篇 |
1995年 | 149篇 |
1994年 | 105篇 |
1993年 | 105篇 |
1992年 | 19篇 |
1991年 | 39篇 |
1990年 | 34篇 |
1989年 | 18篇 |
1988年 | 26篇 |
1987年 | 31篇 |
1986年 | 27篇 |
1985年 | 34篇 |
1983年 | 1篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 10篇 |
1978年 | 4篇 |
1977年 | 27篇 |
1976年 | 104篇 |
1975年 | 6篇 |
1955年 | 1篇 |
排序方式: 共有1984条查询结果,搜索用时 15 毫秒
11.
AK Ghosh 《Canadian Metallurgical Quarterly》1976,8(1):17-26
We report the existence of a surface configuration in a true spore-forming genus having cell wall constituents of type IV. Micropolyspora angiospora, M. caesia and M. faeni freeze-fractured along the wall surface and only had a surface configuration on their aerial mycelium and aerial spores, with none on the substrate mycelium and substrate spore. The surface configuration of Micropolyspora was distinctly more complicated than that of Nocardia. The aerial spores of M. angiospora were characteristic in that they possessed ridges, two kinds of surface configurations (i.e. rodlets and fibres), and a complex pattern on the surface. Some rodlets of this organism were formed of a two-stranded helix, each strand having a diameter similar to that of a fibre. 相似文献
12.
13.
14.
Plasma growth hormone (GH) of eight young, sexually mature, pedigree bulls, observed at hourly intervals, varied during the day in a manner indicating intermittent secretion in peaks or bursts. The diurnal GH averages were about 10 ng/ml. GH averages for 2-3 h intervals showed minima following or during the periods of morning and afternoon feeding. A third minimum occurred between 10 and 12 p.m. Peak activity, estimated by the frequency of GH values greater than 10 ng/ml was significantly reduced during two of these low-GH-periods (afternoon and late night). The minima in GH followed after (morning) or coincided with (afternoon) maxima in plasma insulin (two materials, GH/insulin, 11 a. m.-10 p.m.: r=-0.31 and -3.34, P less than 0.01). This means that the two hormones behaved after food intake much in the same ways as in man in spite of the fact that plasma sugar decreased after feeding (GH/sugar, 11 a.m.-10 p.m.: r=0.27, two materials combined, P less than 0.001). The possibility of GH involvement in the hour-to-hour metabolic homoeostasis of the animals is discussed. 相似文献
15.
RW Ashford ML Chance F Ebert LF Schnur AK Bushwereb SM Drebi 《Canadian Metallurgical Quarterly》1976,70(4):401-409
When mammalian sperm cells are exposed to solutions of albumin there are changes in the membranes of some species that resemble those that normally occur in the uterus prior to fertilization. We have shown that albumin molecules absorb on to the membranes of ejaculated rabbit sperm cells, and that the equilibrium binding constant, K, (1) varies inversely with the albumin concentration, (2) is independent of the sperm cell concentration in the range of 10(6)--10(7) per ml, (3) is independent of the time of exposure of the sperm cells to the albumin solution, and (4) decreases in the presence of Ca++ and Mg++ ions. An unusual aspect of the adsorption is that if the albumin concentration is given the symbol [A], K[A] is a constant in our measurements. This means that for virtually the entire range of [A] studied, the sperm cells bind albumin so that half of the available surface is coated and half remains uncoated. This situation is rather remarkable and it suggests a role that adsorption could play in the physical processes preceding fertilization. In purely physical systems, the optimum for the bridging and flocculation of particles that are coated with adsorbed macromolecular films occurs when half of the available surface is covered. The sperm cell appears to provide the optimal situation for interacting with itself or with another surface. 相似文献
16.
17.
EG Il'inskaia AK Pankov IuS Sidorenko VM Birbraer IuN Bordiushkov 《Canadian Metallurgical Quarterly》1976,22(10):38-44
In the gynecological department of Rostov Oncological Institute endolymphatic polychemotherapy with a preliminary determination of tumor sensitivity to chemotherapy was employed in 54 patients with cervical cancer, 3 of them in stage III and IV having contraindications to radiotherapy. A combination of chemical substances and the dosage of single administration were as follows: thio-TEPA--100--150 mg + methotrexate 75--100 mg; thio-TEPA--100--150 mg + 5-fluoruracil--1000 mg; cyclophosphane--2000 mg + methotrexate--75--100 mg; cyclophosphane--1600 mg + methotrexate--75--100 mg + 5-fluoruracil--750 mg. Lymphoinfusion was made in the lower extremity, and after 7--10 days it was repeated in the second one. Visual disappearance of the tumor was noted in 17 patients, lessening of the tumor size by two-thirds--in 16, a 1/2 decrease--in 20. Among 23 patients in stage III after the treatment parametrial infiltrations disappeared entirely in 11 cases and only in pelvic walls--in 12. In 40 cases an extensive extirpation of the uterus with adnexa was performed. In all cases degenerative changes in tumor tissues were observed, whereas in 7 cases no tumor cells were found. 相似文献
18.
19.
20.
1. The use of Li pre-treatment in rats before high pressure oxygen exposure has been reported effective in controlling convulsions. This is an effect which is better demonstrated if exposure to oxygen follows shortly after Li injection than exposure following several hours later. 2. This study has investigated the hypothesis that the protective action of Li may be exerted, in the short term, by its removing ammonia from the blood and alleviating the latter's known toxic action. 3. A normal Li distribution time profile in unstressed rat brain and blood following intraperitoneal injection has been established. Brain and blood ammonia, amino acids and Li concentrations were also measured in Li-treated animals exposed and convulsed by oxygen. These measurements were made both shortly (15 min) and also several hours after (24 hr) Li treatment. Ammonia and amino acid values in Li-protected groups were compared to normal unstressed animal values and also to values in animals convulsed by oxygen unprotected by Li pre-treatment. 4. In rat brain abd blood significant (P less than 0-001) elevation of ammonia and glutamine and depression of gamma-amino butyric acid (brain only) and glutamate was noted following oxygen treatment in unprotected animals. Prior injection of Li 15 min before high pressure oxygen exposure delayed convulsions twice as long. Additionally if these animals were only exposed to oxygen for a period of time equal to that which would normally produce convulsions in unprotected animals, brain and blood ammonia and amino acids were maintained near to unstressed animal levels. Concomitantly, blood Li concentrations were considerably depressed below the values one would expect from the previously determined Li distribution time profile. 5. In rats exposed to high pressure oxygen 24 hr after Li treatment there was no protective action against high pressure oxygen convulsion, rather a potentiating effect for convulsion was seen. 6. These data present compelling evidence for the controlling effect of Li in rats, on rising blood ammonia concentration which occurs in high pressure oxygen exposure. The effect might well be due to the known chelating properties of Li with ammonia. 相似文献