全文获取类型
收费全文 | 2535篇 |
免费 | 2篇 |
专业分类
电工技术 | 2篇 |
综合类 | 2篇 |
化学工业 | 8篇 |
金属工艺 | 1篇 |
机械仪表 | 2篇 |
建筑科学 | 4篇 |
能源动力 | 2篇 |
轻工业 | 7篇 |
石油天然气 | 1篇 |
无线电 | 3篇 |
一般工业技术 | 18篇 |
冶金工业 | 2449篇 |
自动化技术 | 38篇 |
出版年
2022年 | 3篇 |
2021年 | 2篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2012年 | 1篇 |
2011年 | 7篇 |
2010年 | 1篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 7篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 6篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 73篇 |
1998年 | 750篇 |
1997年 | 421篇 |
1996年 | 305篇 |
1995年 | 150篇 |
1994年 | 132篇 |
1993年 | 145篇 |
1992年 | 13篇 |
1991年 | 25篇 |
1990年 | 25篇 |
1989年 | 21篇 |
1988年 | 26篇 |
1987年 | 22篇 |
1986年 | 18篇 |
1985年 | 14篇 |
1984年 | 1篇 |
1983年 | 7篇 |
1982年 | 15篇 |
1981年 | 15篇 |
1980年 | 24篇 |
1979年 | 3篇 |
1978年 | 12篇 |
1977年 | 62篇 |
1976年 | 177篇 |
1975年 | 4篇 |
1973年 | 2篇 |
1965年 | 1篇 |
1964年 | 3篇 |
1963年 | 1篇 |
1960年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有2537条查询结果,搜索用时 0 毫秒
61.
GM Evins DN Cameron JG Wells KD Greene T Popovic S Giono-Cerezo IK Wachsmuth RV Tauxe 《Canadian Metallurgical Quarterly》1995,172(1):173-179
Since the Latin American cholera epidemic began in 1991, 447 isolates of Vibrio cholerae O1 from the Western Hemisphere have been assayed by multilocus enzyme electrophoresis (MEE) to determine allelic variation among 16 enzyme-encoding genes. Two electrophoretic types (ETs) were identified among toxigenic isolates from Latin America: 323 were ET 4, the ET associated with the Latin American epidemic, and 29 were ET 3. Twenty-three of these ET 3 isolates had a distinctive antimicrobial resistance pattern also seen in isolates imported into the United States from Latin America and Southeast Asia. These resistant isolates had an identical ribotype and nearly identical pulsed-field gel electrophoresis (PFGE) patterns. Most nontoxigenic isolates analyzed were not precursors or descendants of toxigenic epidemic strains. MEE provided a population genetic frame-work for the interpretation of PFGE and ribotype data from the isolates in this study. All three methods identified 2 distinct strains of toxigenic V. cholerae O1 currently epidemic in Latin America. 相似文献
62.
63.
64.
W Chalupa B Vecchiarelli DT Galligan JD Ferguson LS Baird RW Hemken RJ Harmon CG Soderholm DE Otterby RJ Annexstad JG Linn WP Hansen FR Ehle DL Palmquist RG Eggert 《Canadian Metallurgical Quarterly》1996,79(5):800-812
Beginning at wk 5 of lactation, 136 cows (34 per treatment) were supplemented daily for 38 wk with 0, 10.3, 20.6, or 41.2 mg of recombinantly derived bST monomer. Cows were obtained from University of Kentucky, University of Minnesota, University of Pennsylvania, and The Ohio State University. Nine cows (4 at 0 mg/d, 1 at 10.3 mg/d, 1 at 20.6 mg/d, and 3 at 41.2 mg/d) did not complete the experiment because of health problems. Data from these cows were included in the reproduction and health databases but not in the production database. Cows supplemented with bST produced more milk, consumed more feed, had lower rates of BW gain, and had improved efficiencies of milk production (conversion of feed and NEL to milk). Additional increases in productivity were modest at 20.6 and 41.2 mg/d versus productivity at 10.3 mg/d of bST. Concentrations of fat, protein, and TS in milk were unaffected. At 10.3 mg/d, bST did not adversely affect reproduction or health. 相似文献
65.
66.
J Holst B Lindblad D Bergqvist O Nordfang PB Ostergaard JG Petersen G Nielsen U Hedner 《Canadian Metallurgical Quarterly》1994,71(2):214-219
The aim was to investigate whether a truncated recombinant Tissue Factor Pathway Inhibitor (TFPI1-161), which lacked the third Kunitz-type domain and the basic c-terminal region, had an antithrombotic effect comparable to LMWH in a randomised double-dummy study. The experimental thrombosis was induced in jugular veins, in a total of 40 rabbits by a combination of destruction of the endothelium and restricted blood flow. Group 1: placebo, gr 2: LMWH 60 anti-FXa IU/kg, gr 3-5: 0.1, 1.0 and 10.0 mg/kg TFPI1-161. TFPI1-161 reduced the thrombus weights in all treated groups, significantly in doses of 1.0 and 10.0 mg/kg compared to placebo. The frequency of thrombosis and occlusive thrombosis were also significantly reduced in those doses. The antithrombotic properties of TFPI1-161 (1.0-10.0 mg/kg) measured as thrombus weight, frequency of thrombosis and frequency of occlusive thrombosis was equivalent to the anti-thrombotic properties of LMWH. In the anti-FXa, APTT and PT-assays TFPI1-161 displayed a dose dependent increase of activity. Recombinant-TFPI1-161 did not influence the anti-FIIa-assay. No haemorrhagic side effects were noted. 相似文献
67.
JG Bri?ón R Arévalo C Crespo IG Bravo K Okazaki H Hidaka J Aijón JR Alonso 《Canadian Metallurgical Quarterly》1998,795(1-2):204-214
The morphological characteristics and distribution of neurocalcin (NC)-immunoreactive elements were studied in the rat main olfactory bulb (OB) using a polyclonal antibody and the avidin-biotin immunoperoxidase method. NC-positive elements were abundant in the glomerular layer (GL), where numerous immunostained external tufted cells and periglomerular cells were detected. Other less abundant NC-immunolabeled populations included middle and internal tufted cells, Van Gehuchten cells, horizontal cells, vertical cells of Cajal, deep short-axon cells and granule cells. This study demonstrates the presence of NC immunoreactivity in subsets of different neuronal types in the rat main OB. This calcium-binding protein has been found in interneurons, and no evidence of immunoreactivity to NC is detected in projecting neurons. Despite the large population of labeled external tufted cells, most of them belong according to morphological criteria to the local circuit group and some others to those with interbulbar and/or intrabulbar connections. The identification of neuronal subpopulations expressing NC provides a further characterization and shows the existence of biochemical differences within morphologically identical neurons. Thus, this marker may be a useful tool in unravelling the circuitries of the rodent OB in both normal and experimental conditions. The exact physiological function of NC in the olfactory system remains unknown. On the basis of similarities to recoverin, it could be involved in mechanisms responsible for sensory adaptation. Additionally, its calcium-binding abilities may contribute to improve the temporal precision of stimuli transmission, or be concerned with general calcium-related events occurring in specific interneuronal groups. 相似文献
68.
HK Najm GS Van Arsdell S Watzka L Hornberger JG Coles WG Williams 《Canadian Metallurgical Quarterly》1998,116(6):905-913
OBJECTIVE:The objective was to explore the best management algorithm for atrioventricular septal defect in conjunction with tetralogy of Fallot. METHODS: We reviewed the cases of 38 children referred to our division (March 1981-August 1997) who had atrioventricular septal defect associated with tetralogy of Fallot; 32 (84%) had Down syndrome. Twenty-one received initial palliation with a systemic-to-pulmonary artery shunt; of these, 2 (9.5%) died before complete repair. Thirty-one children underwent complete repair; 14 of these (45%) had undergone initial palliation (mean age at shunt 20 +/- 24 months). Right ventricular outflow obstruction was relieved by a transannular patch in 22 (71%); 14 (64% of 22) had a monocuspid valve inserted. Four required an infundibular patch. RESULTS: Two children (6.4%) died early after repair; 1 had undergone previous palliation. Patients with palliation underwent repair at an older age (78 vs 36 months), required longer ventilatory support (8 vs 4 days) and inotropic support (8 vs 4 days), and had longer intensive care stays (11 vs 6 days) and hospital stays (24 vs 15 days). Eleven children (35%) underwent reoperation, 7 (58%) for right ventricular outflow reconstruction and pulmonary arterioplasty. Reoperation was more frequent in the palliation group than in the primary operation group (64% vs 12%). The single late death was related to a reoperation in the palliation group. CONCLUSIONS: Atrioventricular septal defect with tetralogy of Fallot can be repaired with a low mortality rate. Initial palliation with a shunt resulted in a more complex postoperative course and a higher reoperative rate. Primary repair is superior to initial palliation with later repair. 相似文献
69.
70.
The menopausal transition needs to be understood in terms of the multiple mediating factors within the context in which women experience it. For immigrant women especially, the menopausal experience is complicated by multiple transitions and social marginality, so it cannot be adequately explained without considering this complexity. In this paper we review the literature on the menopausal transition of a group of vulnerable immigrant women in two ways: describing the transitions themselves (menopause, immigration, and housewife to employee), and describing factors that mediate the menopausal transition experience (family norms, meaning of menopause and women's work, and health practices). We emphasize the context and suggest areas of needed research. 相似文献