全文获取类型
收费全文 | 903篇 |
免费 | 2篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 3篇 |
金属工艺 | 10篇 |
机械仪表 | 8篇 |
建筑科学 | 21篇 |
矿业工程 | 1篇 |
轻工业 | 2篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
无线电 | 16篇 |
一般工业技术 | 14篇 |
冶金工业 | 789篇 |
自动化技术 | 34篇 |
出版年
2019年 | 3篇 |
2018年 | 4篇 |
2016年 | 2篇 |
2014年 | 4篇 |
2013年 | 3篇 |
2011年 | 2篇 |
2010年 | 7篇 |
2008年 | 2篇 |
2005年 | 1篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 21篇 |
1998年 | 212篇 |
1997年 | 115篇 |
1996年 | 83篇 |
1995年 | 47篇 |
1994年 | 45篇 |
1993年 | 37篇 |
1992年 | 8篇 |
1991年 | 1篇 |
1990年 | 10篇 |
1989年 | 12篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 14篇 |
1980年 | 18篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 69篇 |
1976年 | 96篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1968年 | 4篇 |
1967年 | 4篇 |
1965年 | 2篇 |
1964年 | 3篇 |
1955年 | 1篇 |
排序方式: 共有905条查询结果,搜索用时 0 毫秒
31.
32.
33.
II Gitel'zon VP Nefedov VV Mezhevikin VA Samo?lov IuV Kotlovski? 《Canadian Metallurgical Quarterly》1977,84(7):23-24
Hypoxemia (45-minute) influence in vivo on erythropoietic activity of the kidney, liver, spleen, and sternum was studied by normoxemic perfusion of the isolated organs. The erythropoietic activity proved to increase after 6-hour perfusion of the liver; this confirmed the participation of this organ in the extrarenal secretion of the erythropoietic factor. 相似文献
34.
Studied the cardiovascular response to the stress of mental arithmetic in 121 young Black and White adults. Stress-induced reactivity was studied before and following 14 days of oral sodium loading (10 gm NaCl per day). Marginal hypertensives, both Black and White, had greater systolic blood pressure (SBP) levels and greater diastolic BP levels in response to stress. Whites had a greater SBP level during mental stress than Blacks and greater reactivity. The prevalence of sodium sensitivity was greater in Blacks (37.3%) than in Whites (18.4%). Sodium loading did not augment the BP reactivity to the mental stress in any of the racial or BP groups. Data demonstrate racial variation in the cardiovascular response to centrally medicated adrenergic stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
35.
36.
The present study employed intramuscular (i.m.) injections of the acetylcholine (ACh) receptor antagonist scopolamine hydrobromide (0.10 mg/kg) to investigate the possible involvement of ACh in naturally occurring spatial navigation in homing pigeons (Columba livia). Control pigeons receiving injections of saline or scopolamine methylbromide, an ACh antagonist that does not cross the blood-brain barrier, were oriented in a homeward direction when released from a location 8 km from home. In contrast, pigeons injected with scopolamine hydrobromide (0.10 mg/kg, i.m.) were less well oriented and took more time to return home from the same location. These results suggest that homing pigeon navigation is regulated, in part, by central cholinergic mechanisms. 相似文献
37.
131I dose-dependent thyroid autoimmune disorders in children living around Chernobyl 总被引:1,自引:0,他引:1
EV Vykhovanets VP Chernyshov II Slukvin YG Antipkin AN Vasyuk HF Klimenko KW Strauss 《Canadian Metallurgical Quarterly》1997,84(3):251-259
The nucleotide sequence of 35,400 bp at approximately 10 kb from the right telomere of chromosome VII was determined. The segment contains the MAL1 locus, one of the five unlinked loci sufficient for maltose utilization. Until now, each of these loci was considered to contain three genes (for regulator, permease and alpha-glucosidase), but a fourth gene, presumably an extra alpha-glucosidase gene, was found at MAL1 adjacent to the usual cluster of three genes. The two glucosidase genes are present in opposite orientation, forming an inverted repeat structure. In addition to the four genes at MAL1, there are 11 complete, non-overlapping open reading frames (ORFs) longer than 300 bp in the sequence presented here. A new ABC transporter gene (YGR281w), required for oligomycin resistance was found (YOR1; Katzman et al., 1995), and the previously sequenced BGL2 (YGR282c), ZUO1 (YGR285c) and BIO2 (YGR286c) genes were located. The sequence of BIO2, a biotin synthetase gene, required substantial correction and the size of Bio2p is 375, rather than 356, amino acids. Two ORFs show rather weak similarities to animal genes: YGR278w to an unknown ORF of Caenorhabditis elegans and YGR284c to the murine Surf-4, a member of a cluster of at least four housekeeping genes. The remaining five ORFs do not encode known functions, but three of these show weak to high similarities to other ORFs in the Saccharomyces cerevisiae genome and one (YGR280c) codes for a particularly lysine-rich protein. 相似文献
38.
M Bauchinger K Salassidis H Braselmann A Vozilova S Pressl G Stephan G Snigiryova VP Kozheurov A Akleyev 《Canadian Metallurgical Quarterly》1998,73(6):605-612
Bone morphogenetic proteins (BMPs) and their receptors (BMPRs) are thought to play an important role in bone morphogenesis. The purpose of this study was to determine the locations of BMP-2/-4, osteogenic protein-1 (OP-1, also termed BMP-7), and BMP type II receptor (BMPR-II) during rat fracture healing by immunostaining, and thereby elucidate the possible roles of the BMPs and BMPR-II in intramembranous ossification and endochondral ossification. In the early stage of fracture repair, the expression of BMP-2/-4 and OP-1 was strongly induced in the thickened periosteum near the fracture ends, and coincided with an enhanced expression of BMPR-II. On day 7 after fracture, staining for BMP-2/-4 and OP-1 immunostaining was increased in various types of chondrocytes, and was strong in fibroblast-like spindle cells and proliferating chondrocytes in endochondral bone. On day 14 after fracture, staining with OP-1 antibody disappeared in proliferating and mature chondrocytes, while BMP-2/-4 staining continued in various types of chondrocytes until the late stage. In the newly formed trabecular bone, BMP-2/-4 and OP-1 were present at various levels. BMPR-II was actively expressed in both intramembranous ossification and endochondral ossification. Additionally, immunostaining for BMP-2/-4 and OP-1 was observed in multinucleated osteoclast-like cells on the newly formed trabecular bone, along with BMPR-II. In reference to our previous study of BMP type I receptors (BMPR-IA and BMPR-IB), BMPR-II was found to be co-localized with BMPR-IA and BMPR-IB. BMP-2/-4 and OP-1 antibodies exhibited distinct and overlapping immunostaining patterns during fracture repair. OP-1 may act predominantly in the initial phase of endochondral ossification, while BMP-2/-4 acts throughout this process. Thus, these findings suggested that BMPs acting through their BMP receptors may play major roles in modulating the sequential events leading to bone formation. 相似文献
39.
40.
Elli Ntakou Ralph Masiello Farnaz Farzan Shay Bahramirad Aleksi Paaso M.A. Nayeem Maigha Maigha Daniel Kushner 《The Electricity Journal》2019,32(4):45-49
This paper presents part of the work ComEd and Quanta Technology have performed to quantify the locational and temporal value of DER to avoid distribution grid upgrade investments. It focuses on the formulation of a robust and efficient algorithm for DER optimal dispatch on a distribution feeder to mitigate the violation of current and voltage limits using the allocated cost of capacity and locational marginal value of real and reactive DER injection/withdrawal. 相似文献