全文获取类型
收费全文 | 1006篇 |
免费 | 2篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 16篇 |
金属工艺 | 19篇 |
机械仪表 | 5篇 |
建筑科学 | 10篇 |
矿业工程 | 3篇 |
能源动力 | 21篇 |
轻工业 | 12篇 |
无线电 | 6篇 |
一般工业技术 | 37篇 |
冶金工业 | 863篇 |
原子能技术 | 2篇 |
自动化技术 | 13篇 |
出版年
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 10篇 |
2013年 | 11篇 |
2012年 | 12篇 |
2011年 | 11篇 |
2010年 | 5篇 |
2009年 | 10篇 |
2008年 | 6篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 8篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1999年 | 19篇 |
1998年 | 276篇 |
1997年 | 151篇 |
1996年 | 101篇 |
1995年 | 52篇 |
1994年 | 43篇 |
1993年 | 48篇 |
1992年 | 13篇 |
1991年 | 12篇 |
1990年 | 6篇 |
1989年 | 10篇 |
1988年 | 11篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1985年 | 11篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 12篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 21篇 |
1976年 | 56篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1967年 | 2篇 |
1958年 | 1篇 |
排序方式: 共有1008条查询结果,搜索用时 15 毫秒
61.
62.
A. F. Iyudin V. V. Bogomolov S. I. Svertilov I. V. Yashin N. V. Klassen S. Z. Shmurak A. D. Orlov 《Instruments and Experimental Techniques》2009,52(6):774-781
The intrinsic background was measured in LaBr3:Ce and CeBr3 scintillating crystals grown at the Institute of Solid-State Physics of the Russian Academy of Sciences. The measurements were taken in the range of γ-ray energies from 20 keV to ~5 MeV. Cylindrical samples with dimensions of Ø 1.5 × 1.8 cm for LaBr3:Ce and Ø 0.5 × 1.5 cm for CeBr3 were used. Well-known peculiarities due to the 138La radioactive iso-tope and actinide contaminants were reproduced in the recorded background spectrum of the LaBr3:Ce crystal. The detailed spectrum of the intrinsic background in the CeBr3 crystal was measured for the first time. At energies of >200 keV, the background rate of CeBr3 appeared to be much lower than that of LaBr3:Ce both in the continuum and in the peculiarities associated with the radioactivity of possible contaminants. 相似文献
63.
64.
The modification of reactive protein sulfhydryls by S-nitrosoglutathione and other NO donors has been studied by gel isoelectric focusing. S-nitrosylated, unmodified, and S-glutathiolated protein forms are differentiated by this method. With specific antibodies for the protein of interest, both S-nitrosylation and S-glutathiolation of the protein were analyzed in mixtures obtained as soluble tissue or cell extracts. The effect of S-nitrosoglutathione (GSNO) on purified phosphorylase b, on carbonic anhydrase III in an extract from rat liver, and on H-ras expressed in Escherichia coli was examined. When fresh GSNO reacted with pure phosphorylase b, only S-nitrosylated forms of the protein were observed. Likewise the NO donors, amyl nitrite, spermine NONOate, and diethylamine NONOate, all generated S-nitrosylated phosphorylase b. When crude mixtures of proteins from rat liver (containing carbonic anhydrase III) or from E. coli (containing an overexpressed form of H-ras) were exposed to fresh GSNO, both the S-nitrosylated and the S-glutathiolated forms of the proteins were observed. It is suggested that reactive intermediates from the breakdown of GSNO are responsible for the observed S-glutathiolation. These experiments show that both S-nitrosylated and S-glutathiolated forms of proteins may be generated by the addition of GSNO to mixtures containing proteins with reactive sulfhydryls. These protein modifications may exhibit metabolic consequences independent of the release of nitric oxide. 相似文献
65.
We studied the effect of rehabilitation strength training and return to activities on anterior-posterior knee displacements after patellar tendon autogenous anterior cruciate ligament reconstruction. A total of 938 measurements were sequentially collected for 142 patients with the KT-2000 arthrometer. Rehabilitation included immediate knee motion and early weightbearing, light sports at 6 months, and competitive sports at 8 months or later. At a minimum of 2 years after surgery, 121 patients (85%) had normal displacements (less than 3 mm of increase at 134 N), 14 (10%) had 3 to 5.5 mm of increase (partial function), and 7 (5%) had more than 5.5 mm of increase (failed). There was no association found between the initial onset of the abnormal displacements in the 21 knees and either the amount of time after surgery or the rehabilitation program. Six of the seven grafts that failed did so in the 1st postoperative year. Serial displacement measurements allow early detection of graft stretching and subsequent modification of rehabilitation or delay in return to strenuous activities. These measurements showed that the rehabilitation program used in this study was not itself injurious and resulted in an acceptable failure rate of 5%. 相似文献
66.
The linear cytoplasmic element pPE1B from Pichia etchellsii CBS2011 (synonym Debaryomyces etchellsii) was totally sequenced. It consists of 12835 bp and has a remarkable high A+T content of 77.3%. The termini of pPE1B were found to consist of inversely orientated identical nucleotide repetitions 161 base pairs long, to which proteins are probably covalently linked at the 5' ends. Ten putative genes (open reading frames, ORFs) were identified, covering 96.5% of the total sequence. The predicted polypeptides correspond to proteins encoded by ORFs 2-11 of the linear plasmids pGKL2 of Kluyveromyces lactis and pSKL of Saccharomyces kluyveri. ORF1, existing on both latter elements, is lacking on pPE1B. An upstream conserved sequence motif (UCS) is located at the expected distance from the start codon of each of the 10 ORFs. As the arbitrarily chosen UCS6 was able to drive expression of a reporter gene in the heterologous pGKL-encoded killer system of K. lactis, extranuclear promoter function is probable. The almost congruent genome organization of pPE1B and other autonomous linear yeast plasmids sequenced so far, i.e. pGKL2 and pSKL, suggests a common, presumably viral, ancestor. 相似文献
67.
68.
69.
Erectile dysfunction is a common (affecting 10-20 million men in the USA) and multifactorial disease due to organic and/or psychological factors that strongly impairs the quality of life in man. During the past decade many advances in the understanding of the pathophysiology of erectile dysfunction have been made and new therapeutic strategies have become available. It has been established that an insufficient production of nitric oxide by penile nerve terminals and/or vascular endothelium may result in an impaired erection or complete impotence. Nowadays, intracavernous injection of vasoactive drugs represents a standardized approach for the diagnosis, and the treatment of choice, for erectile dysfunction, but is not widely accepted by the patients. The possibility of treating erectile dysfunction with intraurethral administration of prostaglandin-E1 has recently become available in the USA, and is a therapy more acceptable to the patients. Other noninvasive medical therapies are undergoing evaluation. 相似文献
70.
ST O'Sullivan M O'Sullivan N Pasha M O'Shaughnessy TP O'Connor 《Canadian Metallurgical Quarterly》1997,28(9-10):639-642
The patient with severe lower limb trauma presents a management dilemma; whether to amputate primarily or to attempt limb salvage. In recent years, many predictive indices have been published which purport to identify limbs which are non-viable. We retrospectively applied two recently described indices, the Mangled Extremity Severity Score (MESS) and the Limb Salvage Index (LSI), to 54 limbs in 50 patients with either Gustilo IIIB or IIIC complex tibial fractures. There were 22 amputations (40.7 per cent) in the series. The mean MESS score in the limb salvage group was 3.8 (range 2-10), and the mean MESS score in the amputation group was 7.7 (range 4-13) (P < 0.0001). The mean LSI score in the limb salvage group was 3.6 (range 3-8), and the mean LSI score in the amputation group was 6.9 (P < 0.01). However, in the group with MESS scores > 7 (which recommends amputation), there were three limbs which were salvaged with acceptable functional outcome. Similarly, in those with LSI scores > 6 (which recommends amputation), there were seven limbs successfully salvaged. A MESS > 7 offered a greater relative risk of amputation (9.2) than a LSI score > 6 (5.3). We found both indices of use in predicting limb salvage and functional outcome. However, neither is sufficiently accurate to be considered absolutely reliable in clinical practice. 相似文献