全文获取类型
收费全文 | 2016篇 |
免费 | 0篇 |
专业分类
电工技术 | 5篇 |
综合类 | 1篇 |
化学工业 | 22篇 |
建筑科学 | 4篇 |
矿业工程 | 2篇 |
能源动力 | 2篇 |
轻工业 | 33篇 |
无线电 | 20篇 |
一般工业技术 | 31篇 |
冶金工业 | 1860篇 |
自动化技术 | 36篇 |
出版年
2020年 | 1篇 |
2019年 | 2篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2014年 | 2篇 |
2013年 | 7篇 |
2012年 | 4篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 5篇 |
2004年 | 6篇 |
2003年 | 8篇 |
2002年 | 4篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 60篇 |
1998年 | 546篇 |
1997年 | 307篇 |
1996年 | 225篇 |
1995年 | 114篇 |
1994年 | 95篇 |
1993年 | 127篇 |
1992年 | 23篇 |
1991年 | 26篇 |
1990年 | 18篇 |
1989年 | 41篇 |
1988年 | 26篇 |
1987年 | 31篇 |
1986年 | 17篇 |
1985年 | 23篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 15篇 |
1981年 | 14篇 |
1980年 | 17篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 63篇 |
1976年 | 124篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1968年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有2016条查询结果,搜索用时 31 毫秒
101.
102.
Arthur Jutan J. D. Wright J. F. MacGregor 《American Institute of Chemical Engineers》1984,30(2):220-226
A multivariable stochastic controller is implemented on a pilot scale, plug flow, butane hydrogenolysis reactor. In the synthesis of the controller, a multivariate time series model of the process disturbances is used. The success of this controller is compared to a previous controller where the process disturbances are not directly modeled. 相似文献
103.
Staphylococcus aureus produces and secretes a protein, Efb, that binds to fibrinogen, seems to be required for virulence, and may benefit the microorganism by delaying wound healing. Interactions of Efb with fibrinogen are influenced by divalent metal cations, including Ca2+. Increasing concentrations of Ca2+ increased the binding of fibrinogen to immobilized Efb, whereas binding of Efb to immobilized fibrinogen was decreased with increasing Ca2+ concentration. Studies with synthetic peptides showed that peptides from the carboxyl terminal half of Efb bound to soluble fibrinogen and enhanced the binding of fibrinogen to Efb. A peptide corresponding to a repeated sequence in the amino terminal half of the protein also bound fibrinogen and inhibited binding of fibrinogen to Efb. These results may provide clues to the biological function of Efb and aid in the rational design of agents to block the Efb fibrinogen interaction. 相似文献
104.
Recently, the authors presented evidence that new items can be prioritized for selection by the top-down attentional inhibition of old stimuli already in the field (visual marking; D. G. Watson & G. W. Humphreys, 1997). In this article the authors assess whether this inhibition extends to moving old items and test an alternative account of visual marking. Six experiments showed that old moving items could be inhibited provided they did not undergo abrupt property changes. Further, and in contrast to effects with static stimuli, the marking of old moving stimuli was based on inhibition applied at the level of a whole feature map, rather than at their locations. The results also rule out an alternative account of visual marking based on the top-down weighting of dynamic or static processing pathways. 相似文献
105.
SK Thompson WW Smith B Zhao SM Halbert TA Tomaszek DG Tew MA Levy CA Janson KJ DAlessio MS McQueney J Kurdyla CS Jones RL DesJarlais SS Abdel-Meguid DF Veber 《Canadian Metallurgical Quarterly》1998,41(21):3923-3927
Peptidomimetic cathepsin K inhibitors have been designed using binding models which were based on the X-ray crystal structure of an amino acid-based, active site-spanning inhibitor complexed with cathepsin K. These inhibitors, which contain a benzyloxybenzoyl group in place of a Cbz-leucine moiety, maintained good inhibitory potency relative to the amino acid-based inhibitor, and the binding models were found to be very predictive of relative inhibitor potency. The binding mode of one of the inhibitors was confirmed by X-ray crystallography, and the crystallographically determined structure is in close qualitative agreement with the initial binding model. These results strengthen the validity of a strategy involving iterative cycles of structure-based design, inhibitor synthesis and evaluation, and crystallographic structure determination for the discovery of peptidomimetic inhibitors. 相似文献
106.
CT Wass JR Waggoner DG Cable HV Schaff DR Schroeder WL Lanier 《Canadian Metallurgical Quarterly》1998,115(6):1350-1357
BACKGROUND: Neurologic complications, primarily resulting from ischemic insults, represent the leading cause of morbidity and disability, and the second most common source of death, after cardiac operations. Previous studies have reported that increases (as occur during the rewarming phase of cardiopulmonary bypass [CPB]) or decreases in brain temperature of a mere 0.5 degrees to 2 degrees C can significantly worsen or improve, respectively, postischemic neurologic outcome. The purpose of the present study was to evaluate a novel approach of selectively cooling the brain during hypothermic CPB and subsequent rewarming. METHODS: Sixteen dogs were anesthetized with either intravenous pentobarbital or inhaled halothane (n = 8 per group). Normocapnia (alpha stat technique) and a blood pressure near 75 mm Hg were maintained. Temperatures were monitored by placing thermistors in the esophagus (i.e., core), parietal epidural space, and brain parenchyma at depths of 1 and 2 cm beneath the dura. During CPB, core temperature was actively cycled from 38 degrees C to 28 degrees C, and then returned to 38 degrees C. Forced air pericranial cooling (air temperature of approximately 13 degrees C) was initiated simultaneous with the onset of CPB, and maintained throughout the bypass period. Brain-to-core temperature gradients were calculated by subtracting the core temperature from regional brain temperatures. RESULTS: In halothane-anesthetized dogs, brain temperatures at all monitoring sites were significantly less than core during all phases of CPB, with one exception (2 cm during systemic cooling). Brain cooling was most prominent during and after systemic rewarming. For example, during systemic rewarming, average temperatures in the parietal epidural space, and 1 and 2 cm beneath the dura, were 3.3 degrees +/- 1.3 degrees C (mean +/- standard deviation), 3.2+/-1.4 degrees C, and 1.6 degrees +/-1.0 degrees C, cooler than the core, respectively. Similar trends, but of a greater magnitude, were noted in pentobarbital-anesthetized dogs. For example, during systemic rewarming, corresponding brain temperatures were 6.5 degrees +/-1.7 degrees C, 6.3 degrees +/-1.6 degrees C, and 4.2+/-1.3 degrees C cooler than the core, respectively. CONCLUSIONS: The magnitude of selective brain cooling observed in both study groups typically exceeded the 0.5 degrees to 2.0 degrees C change previously reported to modulate ischemic injury, and was most prominent during the latter phases of CPB. When compared with previous research from our laboratory, application of cold forced air to the cranial surface resulted in brain temperatures that were cooler than those observed during hypothermic CPB without pericranial cooling. On the basis of the assumption that similar beneficial brain temperature changes can be induced in humans, we speculate that selective convective brain cooling may enable clinicians to improve neurologic outcome after hypothermic CPB. 相似文献
107.
RA Nugent M Murphy ST Schlachter CJ Dunn RJ Smith ND Staite LA Galinet SK Shields DG Aspar KA Richard 《Canadian Metallurgical Quarterly》1993,36(1):134-139
Vinylidenebisphosphonic acid tetraethyl ester (1) and diazo ketones 7a-1 in ether at 22 degrees C yield pyrazoline bisphosphonate tetraethyl esters 8a-1 in moderate to good yield. These compounds were evaluated in animal models of arthritis: rat adjuvant-induced polyarthritis (AIP) and murine antigen-induced arthritis (AIA) and a murine model of chronic inflammation, the delayed type hypersensitivity granuloma reaction (DTH-GRA). (5-Benzoyl-2,4-dihydro-3H-pyrazol-3-ylidene)-bisphosphonic acid tetraethyl ester (8a), and [5-(3-fluorobenzoyl)-2,4-dihydro-3H-pyraxol-3-ylidene]- bisphosphonic acid tetraethyl ester (8d) significantly inhibited the arthritis models, AIP (15 mg/kg) and AIA (25 mg/kg), as well as the DTH-GRA (25 mg/kg). Conversion of 8a to the corresponding bisphosphonic acid, 10a, resulted in loss of activity. Compounds with alkyl substituents on the pyrazoline nitrogen, 9a-d, were inactive in the DTH-GRA. These results show that 8a and 8d have novel antiinflammatory activity and are capable of inhibiting chronic arthritis and inflammation in animals. Such compounds might be useful in man for treating chronic tissue injury associated with arthropathies such as inflammatory joint disease as well as other chronic inflammatory diseases. 相似文献
108.
109.
110.
J Schwaller J Frantsve J Aster IR Williams MH Tomasson TS Ross P Peeters L Van Rompaey RA Van Etten R Ilaria P Marynen DG Gilliland 《Canadian Metallurgical Quarterly》1998,17(18):5321-5333
Recent reports have demonstrated fusion of the TEL gene on 12p13 to the JAK2 gene on 9p24 in human leukemias. Three variants have been identified that fuse the TEL pointed (PNT) domain to (i) the JAK2 JH1-kinase domain, (ii) part of and (iii) all of the JH2 pseudokinase domain. We report that all of the human TEL/JAK2 variants, and a human/mouse chimeric hTEL/mJAK2(JH1) fusion gene, transform the interleukin-3 (IL-3)-dependent murine hematopoietic cell line Ba/F3 to IL-3-independent growth. Transformation requires both the TEL PNT domain and JAK2 kinase activity. Furthermore, all TEL/JAK2 variants strongly activated STAT 5 by phosphotyrosine Western blots and by electrophoretic mobility shift assays (EMSA). Mice (n = 40) transplanted with bone marrow infected with the MSCV retrovirus containing either the hTEL/mJAK2(JH1) fusion or its human counterpart developed a fatal mixed myeloproliferative and T-cell lymphoproliferative disorder with a latency of 2-10 weeks. In contrast, mice transplanted with a TEL/JAK2 mutant lacking the TEL PNT domain (n = 10) or a kinase-inactive TEL/JAK2(JH1) mutant (n = 10) did not develop the disease. We conclude that all human TEL/JAK2 fusion variants are oncoproteins in vitro that strongly activate STAT 5, and cause lethal myelo- and lymphoproliferative syndromes in murine bone marrow transplant models of leukemia. 相似文献