全文获取类型
收费全文 | 1648篇 |
免费 | 3篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 54篇 |
金属工艺 | 2篇 |
机械仪表 | 8篇 |
建筑科学 | 18篇 |
矿业工程 | 1篇 |
能源动力 | 5篇 |
轻工业 | 19篇 |
水利工程 | 4篇 |
无线电 | 28篇 |
一般工业技术 | 74篇 |
冶金工业 | 1393篇 |
原子能技术 | 2篇 |
自动化技术 | 42篇 |
出版年
2018年 | 3篇 |
2016年 | 2篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 14篇 |
2012年 | 9篇 |
2011年 | 15篇 |
2010年 | 7篇 |
2009年 | 5篇 |
2008年 | 13篇 |
2007年 | 11篇 |
2006年 | 2篇 |
2005年 | 11篇 |
2004年 | 13篇 |
2003年 | 10篇 |
2002年 | 4篇 |
2001年 | 6篇 |
2000年 | 8篇 |
1999年 | 47篇 |
1998年 | 376篇 |
1997年 | 237篇 |
1996年 | 144篇 |
1995年 | 79篇 |
1994年 | 94篇 |
1993年 | 86篇 |
1992年 | 16篇 |
1991年 | 35篇 |
1990年 | 28篇 |
1989年 | 28篇 |
1988年 | 42篇 |
1987年 | 31篇 |
1986年 | 17篇 |
1985年 | 22篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 14篇 |
1980年 | 9篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 54篇 |
1976年 | 98篇 |
1975年 | 6篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1965年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有1651条查询结果,搜索用时 15 毫秒
1.
GW Pratt 《Canadian Metallurgical Quarterly》1997,(23):30-32
A discussion is presented of contributing factors to the injury to the foreleg of the Thoroughbred racehorse. The critical part of the step is taken to be the first 10-20 ms after ground contact as the hoof slides forward and stops. Large nonaxial loads associated with the deceleration of the hoof are shown to arise. Results of accelerometer measurements on the hoof of a horse running at racing speed are presented as well as mechanical properties of the racing surface. The mechanical properties of the track surface, the type of shoe, and the degree of fatigue of the horse all work together to determine the level of risk. 相似文献
2.
3.
4.
Several simple 3D experiments are used to provide J correlations between methionine C epsilon methyl carbons and either the C gamma H2 protons or C beta and C gamma. The intensity of the J correlations provides information on the size of the three-bond J couplings and thereby on the chi 3 torsion angle. In addition, a simple 3D version of the HMBC experiment provides a sensitive link between the C epsilon H3 methyl protons and C gamma. The methods are demonstrated for a 20 kDa complex between calmodulin and a 26-residue peptide fragment of skeletal muscle myosin light chain kinase. 相似文献
5.
6.
7.
Strains of the gastrointestinal species Lactobacillus reuteri were electrotransformed with plasmid constructs containing the endo-1,3-1,4-beta-glucanase gene (bglM) of Bacillus macerans. The enzyme was expressed and secreted by the lactobacilli. A plasmid construct containing the bglM gene lacking its promoter was derived and was demonstrated to be useful as a promoter probe vector. 相似文献
8.
Alpidem, an imidazopyridine that acts at the gamma-aminobutyric acid/benzodiazepine receptor complex, has been reported to be an effective anxiolytic with a more favorable side effect profile than benzodiazepines. The effect of alpidem was investigated in an 8-week, open, clinical trial in 13 patients with panic disorder, with or without agoraphobia. Three patients were responders (much improved or very much improved), five patients were nonresponders, and five patients dropped out after less than 6 weeks of treatment. Significant improvement was seen in the sample as a whole for spontaneous panic attacks, phobic avoidance, and anticipatory anxiety. Most improvement occurred during the first 4 weeks of treatment, and responders had milder panic disorder at baseline. Adverse effects were generally mild. After 8 weeks of treatment, taper of medication over 2 weeks occurred without significant worsening of panic disorder symptoms. The efficacy of alpidem in the treatment of panic disorder remains uncertain and requires assessment in a controlled trial. 相似文献
9.
RM Bionta G Blewitt CB Bratton D Casper A Ciocio R Claus M Crouch ST Dye S Errede GW Foster W Gajewski KS Ganezer M Goldhaber TJ Haines TW Jones D Kielczewska WR Kropp JG Learned JM LoSecco J Matthews HS Park LR Price F Reines J Schulz S Seidel E Shumard D Sinclair HW Sobel JL Stone L Sulak R Svoboda G Thornton van der Velde JC C Wuest 《Canadian Metallurgical Quarterly》1987,36(1):30-36
10.
Excision of perianal fistulas using a 1.064 micron wavelength neodymium:yttrium aluminum garnet (ND:YAG) contact tipped laser with primary wound closure was used to treat 20 dogs with perianal fistulas. Overall, 19 of 20 (95%) dogs had resolution of fistulas after one or more ND:YAG treatments. The period of resolution ranged from 10 to 42 months with a mean of 22.9 months. Sixteen of 20 (80%) dogs had resolved fistulas after one laser excision. Three of the four recurrences underwent additional laser treatments with successful results. The total number of laser procedures ranged from one to three with a mean of 1.2 procedures. Postoperatively, anal tone as judged by digital rectal examination was reduced in about 60% of the cases, but clinical evidence of fecal incontinence only occurred in four of 20 cases. This was managed effectively with diet modification. The tendency toward loss of anal tone or fecal incontinence depended on the severity of preexisting anal stenosis. On a client survey, 19 of 20 owners believed that their animals experienced less pain during defecation after surgery and rated the results as excellent or good. The overall success rate using ND:YAG laser excision compared very favorably with previously reported studies of other methods of treatment for perianal fistulas in dogs. 相似文献