全文获取类型
收费全文 | 629篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 22篇 |
金属工艺 | 15篇 |
机械仪表 | 2篇 |
能源动力 | 1篇 |
轻工业 | 5篇 |
水利工程 | 13篇 |
石油天然气 | 21篇 |
无线电 | 7篇 |
一般工业技术 | 45篇 |
冶金工业 | 494篇 |
原子能技术 | 1篇 |
自动化技术 | 5篇 |
出版年
2020年 | 3篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 5篇 |
2013年 | 4篇 |
2012年 | 7篇 |
2011年 | 10篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 9篇 |
2007年 | 6篇 |
2006年 | 3篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2000年 | 4篇 |
1999年 | 14篇 |
1998年 | 127篇 |
1997年 | 77篇 |
1996年 | 44篇 |
1995年 | 28篇 |
1994年 | 24篇 |
1993年 | 35篇 |
1992年 | 5篇 |
1991年 | 12篇 |
1990年 | 15篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1986年 | 13篇 |
1985年 | 11篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 7篇 |
1977年 | 17篇 |
1976年 | 40篇 |
1975年 | 6篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1968年 | 2篇 |
1966年 | 4篇 |
1965年 | 2篇 |
1963年 | 2篇 |
1960年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有631条查询结果,搜索用时 15 毫秒
71.
KS Ternovo? TN Selezneva AV Akleev IA Pashkov LA Noskin NV Klopov VA Noskin NF Starodub 《Canadian Metallurgical Quarterly》1998,70(3):81-85
The effects of an alternative chelation program in thalassemic patients with severe iron overload are investigated. The schedule of treatment, feasible at home, consists in the administration of deferoxamine intravenously (100 mg/kg/die 8 hours 10 days a month), followed by 50 mg/kg/die subcutaneously in the remaining 20 days of the month. The results in 34 patients who underwent this program over 8 months are reported. After intensive chelation therapy serum ferritin and transaminase levels were significantly lower, and daily urinary iron excretion values were significantly higher when compared to the levels observed before the treatment. After the period of study, echocardiography revealed an ejection fraction (EF) significantly higher in 15 out of 34 cardiopathic patients. In conclusion, the alternative chelation program is effective in reducing iron overload of thalassemic patients, protecting them also against cardiac disease. 相似文献
72.
73.
We have tested the effects of neuromuscular denervation in Drosophila by laser-ablating the RP motoneurons in intact embryos before synaptogenesis. We examined the consequences of this ablation on local synaptic connectivity in both 1st and 3rd instar larvae. We find that the partial or complete loss of native innervation correlates with the appearance of alternate inputs from neighboring motor endings and axons. These collateral inputs are found at ectopic sites on the denervated target muscle fibers. The foreign motor endings are electrophysiologically functional and are observed on the denervated muscle fibers by the 1st instar larval stage. Our data are consistent with the existence of a local signal from the target environment, which is regulated by innervation and influences synaptic connectivity. Our results show that, despite the stereotypy of Drosophila neuromuscular connections, denervation can induce local changes in connectivity in wild-type Drosophila, suggesting that mechanisms of synaptic plasticity may also be involved in normal Drosophila neuromuscular development. 相似文献
74.
AD Anichkov AV Vodianov SV Mozhaev TN Trofimova VB Nizkovolos AV Obliapin IuZ Polonski? AL Spirin 《Canadian Metallurgical Quarterly》1998,(3):6-9; discussion 9-10
The paper summarizes experience with stereotactic operations by magnetic resonance imaging data by using a Russian OREOL stereotactic manipulator. It describes methods of preoperative preparation of patients by employing diagnostic magnetic resonance tomographs. A number of points of the procedure for identification and localization of deep target structures from magnetic resonance images in parkinsonism, temporal epilepsy and some mental disorders. 相似文献
75.
76.
This study evaluated whether human monocyte-derived macrophages synthesize specific types of proteoglycans with lipoprotein-binding capability that could contribute to lipid retention in the arterial wall. After labeling with either [35S]SO4 or [35S]methionine, macrophages secreted a high molecular mass proteoglycan, with glycosaminoglycan chains of approximately 18 kDa and core protein bands of approximately 100 and 55 kDa. Both core protein bands were recognized by an antibody to PG-100, an antibody that recognizes the proteoglycan form of macrophage colony-stimulating factor (PG-100/PG-MCSF). The interaction between PG-100/PG-MCSF and low density lipoproteins (LDL) was examined by gel mobility shift. In this system, PG-100/PG-MCSF was resolved further into two forms. The two forms had the same core proteins but differed in their overall size and glycosaminoglycan content. The larger form contained glycosaminoglycan chains that were entirely chondroitin ABC lyase-sensitive, whereas the smaller form contained chains that were sensitive to both chondroitin ABC lyase and heparinase. Both forms bound native LDL with high affinity, but the larger form bound LDL with higher affinity than the smaller form. The glycosaminoglycan chains of PG-100/PG-MCSF, but not the core proteins, were responsible for binding to native LDL. Mildly oxidized LDL and methyl-LDL, which have an electrophoretic charge similar to that of native LDL, also bound PG-100/PG-MCSF. In contrast, extensively oxidized LDL and acetyl-LDL, which are more electronegative than native LDL, did not bind to either form of PG-100/PG-MCSF. The demonstration of two forms of human monocyte-derived macrophage PG-100/PG-MCSF which bind LDL may represent an additional role for macrophages in the extracellular trapping of lipoproteins in atherosclerosis. 相似文献
77.
KP Williams XH Liu TN Schumacher HY Lin DA Ausiello PS Kim DP Bartel 《Canadian Metallurgical Quarterly》1997,94(21):11285-11290
In vitro selection experiments have produced nucleic acid ligands (aptamers) that bind tightly and specifically to a great variety of target biomolecules. The utility of aptamers is often limited by their vulnerability to nucleases present in biological materials. One way to circumvent this problem is to select an aptamer that binds the enantiomer of the target, then synthesize the enantiomer of the aptamer as a nuclease-insensitive ligand of the normal target. We have so identified a mirror-image single-stranded DNA that binds the peptide hormone vasopressin and have demonstrated its stability to nucleases and its bioactivity as a vasopressin antagonist in cell culture. 相似文献
78.
F Coulin CA Power S Alouani MC Peitsch JM Schroeder M Moshizuki I Clark-Lewis TN Wells 《Canadian Metallurgical Quarterly》1997,248(2):507-515
The aim of this study was to determine the level of endogenous prostaglandin E2 (PGE2), prostaglandin F1 alpha (6-keto-PGF1 alpha) and thromboxane B2 (TXB2) in the gastric and duodenal mucosa of patients with duodenal ulcer and duodenitis. Besides, the investigation aimed at determining the effect of smoking and infection by Helicobater pylori on prostaglandin synthesis. The investigation comprised 62 patients with duodenal ulcer, 46 patients with duodenitis and 44 controls. The results of our investigation indicate that the decreased prostaglandin synthesis in gastric and duodenal mucosa determined in patients with duodenal ulcer may have a considerable role in development of duodenal ulcer. Furthermore, the harmful effects of smoking on the gastric and duodenal mucosa may be mediated by the decreased prostaglandin synthesis in the gastric and duodenal mucosa. However, Helicobacter pylori seems to affect the development of duodenal ulcer through other mechanisms. 相似文献
79.
The commercially available spray management valve provided consistent flow rates when used with hand-compression sprayer systems. The 15-psi spray management valve maintained a constant flow rate of 180, 150, and 155 ml/min in combination with a fine 45 degrees flat fan nozzle and Hudson. B&G, and Chapin hand-compression sprayers, respectively. The 30-psi spray management valve maintained a constant flow rate and adequate spray-on time when combined with the coarse flat fan nozzle for each of the 3 hand-compression sprayers tested. 相似文献