全文获取类型
收费全文 | 3481篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 4篇 |
综合类 | 3篇 |
化学工业 | 26篇 |
金属工艺 | 3篇 |
机械仪表 | 3篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 3篇 |
轻工业 | 10篇 |
石油天然气 | 1篇 |
武器工业 | 2篇 |
无线电 | 10篇 |
一般工业技术 | 11篇 |
冶金工业 | 3380篇 |
自动化技术 | 23篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2014年 | 1篇 |
2013年 | 7篇 |
2012年 | 1篇 |
2011年 | 26篇 |
2010年 | 5篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 11篇 |
2002年 | 4篇 |
2000年 | 4篇 |
1999年 | 118篇 |
1998年 | 1127篇 |
1997年 | 654篇 |
1996年 | 391篇 |
1995年 | 194篇 |
1994年 | 178篇 |
1993年 | 228篇 |
1992年 | 13篇 |
1991年 | 31篇 |
1990年 | 28篇 |
1989年 | 41篇 |
1988年 | 33篇 |
1987年 | 33篇 |
1986年 | 16篇 |
1985年 | 26篇 |
1984年 | 1篇 |
1983年 | 8篇 |
1982年 | 17篇 |
1981年 | 13篇 |
1980年 | 26篇 |
1979年 | 1篇 |
1978年 | 10篇 |
1977年 | 75篇 |
1976年 | 136篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1955年 | 3篇 |
1924年 | 1篇 |
排序方式: 共有3490条查询结果,搜索用时 31 毫秒
181.
182.
183.
PR Burchat GJ Feldman T Barklow AM Boyarski DL Burke JM Dorfan L Gladney G Hanson K Hayes RJ Hollebeek WR Innes JA Jaros D Karlen AJ Lankford RR Larsen BW LeClaire NS Lockyer V Lüth C Matteuzzi RA Ong ML Perl B Richter K Riles MC Ross JM Yelton C Zaiser GS Abrams D Amidei AR Baden J Boyer F Butler G Gidal MS Gold G Goldhaber L Golding J Haggerty D Herrup I Juricic JA Kadyk ME Nelson PC Rowson H Schellman WB Schmidke PD Sheldon GH Trilling de la Vaissiere C DR Wood ME Levi T Schaad 《Canadian Metallurgical Quarterly》1987,35(1):27-41
184.
185.
GA Perkins CW Renken JY Song TG Frey SJ Young S Lamont ME Martone S Lindsey MH Ellisman 《Canadian Metallurgical Quarterly》1997,120(3):219-227
Genome-wide scans for linkage of chromosome regions to type 1 diabetes in affected sib pair families have revealed that the major susceptibility locus resides within the major histocompatibility complex (MHC) on chromosome 6p21 (lambda s = 2.5). It is recognised that the MHC contains multiple susceptibility loci (referred to collectively as IDDM1), including the class II antigen receptor genes, which control the major pathological feature of the disease: T lymphocyte-mediated autoimmune destruction of the insulin-producing pancreatic beta cells. However, the MHC genes, and a second locus, the insulin gene minisatellite on chromosome 11p15 (IDDM2; lambda s = 1.25), cannot account for all of the observed clustering of disease in families (lambda s = 15), and the scans suggested the presence of other susceptibility loci scattered throughout the genome. There are four additional loci for which there is currently sufficient evidence from linkage and association studies to justify fine mapping experiments: IDDM4 (FGF3/11q13), IDDM5 (ESR/6q22), IDDM8 (D6S281/6q27) and IDDM12 (CTLA-4/2q33), IDDM4, 5 and 8 were detected by genome scanning, and IDDM12 by a candidate gene strategy. The results suggest that the clustering of type 1 diabetes in families is due to the sharing of alleles at multiple loci, and that the as yet unidentified environmental factors are not causing clustering, but instead appear to influence the overall penetrance of genetically programmed susceptibility. The data are consistent with a polygenic threshold model for the inheritance of type 1 diabetes. 相似文献
186.
论述了铅始极片生产自动线各机构的工作原理,主要运行参数的分析与选取,该生产线技术先进,经构紧凑合理,指标稳定,运行可靠。 相似文献
187.
H Chao ME Houston RS Hodges CM Kay BD Sykes MC Loewen PL Davies FD S?nnichsen 《Canadian Metallurgical Quarterly》1997,36(48):14652-14660
The most abundant isoform (HPLC-6) of type I antifreeze protein (AFP1) in winter flounder is a 37-amino-acid-long, alanine-rich, alpha-helical peptide, containing four Thr spaced 11 amino acids apart. It is generally assumed that HPLC-6 binds ice through a hydrogen-bonding match between the Thr and neighboring Asx residues to oxygens atoms on the {2021} plane of the ice lattice. The result is a lowering of the nonequilibrium freezing point below the melting point (thermal hysteresis). HPLC-6, and two variants in which the central two Thr were replaced with either Ser or Val, were synthesized. The Ser variant was virtually inactive, while only a minor loss of activity was observed in the Val variant. CD, ultracentrifugation, and NMR studies indicated no significant structural changes or aggregation of the variants compared to HPLC-6. These results call into question the role of hydrogen bonds and suggest a much more significant role for entropic effects and van der Waals interactions in binding AFP to ice. 相似文献
188.
R Kajiwara O Sand Y Kidokoro ME Barish T Iijima 《Canadian Metallurgical Quarterly》1997,47(5):449-464
Optical recordings of membrane depolarization and whole-cell patch-clamp recordings of membrane potentials and currents were obtained from chromaffin cells in slices of rat adrenal medulla. The stimulation of splanchnic nerve fibers caused a discontinuous spread of electrical activity across the slice. Cells in clusters with diameters of about 80 microns were excited simultaneously, suggesting that the adrenal medulla is organized into descrete cell complexes with common innervation. The electrical properties of chromaffin cells in situ were in agreement with previous reports on cultured cells. A fraction of the recorded cells displayed excitatory postsynaptic currents (EPSCs) of 0.2-1 nA upon the stimulation of presynaptic nerve fibers. The EPSC was blocked by hexamethonium, suggesting that nicotinic ACh receptors were involved. The decay phase of the EPSC was well fit by the sum of two exponentials with time constants of 6.3 and 57.3 ms. The relative amplitude of the fast component was 84.1%. These two exponentials may reflect activation of both fast and slow time-constant ACh receptor channels by presynaptic release of ACh. There were multiple peaks in the EPSC amplitude histograms in low-[Ca2+] saline, the first peak was at 37 pA. To resolve the quantal size, miniature EPSCs were recorded in a tetrodotoxin-containing high-[K+] solution. The miniature EPSC amplitude histograms were also multimodal with the first peak at 25 pA, which probably represents the quantal size of the synapse. The second and third peaks were at the integer multiples of the first one. 相似文献
189.
190.
南阳石蜡精细化工厂气体分馏装置采取了几项节能技术改进:回收除盐水,增加加热水渗线,控制液化气C2含量,使用高速泵及变频器等,几年的运行情况表明,这些措施安全可靠,操作方便,减少了装置的水、电、蒸汽消耗。 相似文献