全文获取类型
收费全文 | 1011篇 |
免费 | 57篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 12篇 |
综合类 | 1篇 |
化学工业 | 207篇 |
金属工艺 | 15篇 |
机械仪表 | 14篇 |
建筑科学 | 55篇 |
矿业工程 | 3篇 |
能源动力 | 24篇 |
轻工业 | 164篇 |
水利工程 | 9篇 |
石油天然气 | 1篇 |
无线电 | 63篇 |
一般工业技术 | 191篇 |
冶金工业 | 197篇 |
原子能技术 | 7篇 |
自动化技术 | 106篇 |
出版年
2024年 | 2篇 |
2023年 | 10篇 |
2022年 | 22篇 |
2021年 | 39篇 |
2020年 | 24篇 |
2019年 | 29篇 |
2018年 | 34篇 |
2017年 | 25篇 |
2016年 | 30篇 |
2015年 | 36篇 |
2014年 | 18篇 |
2013年 | 38篇 |
2012年 | 45篇 |
2011年 | 66篇 |
2010年 | 40篇 |
2009年 | 26篇 |
2008年 | 52篇 |
2007年 | 46篇 |
2006年 | 35篇 |
2005年 | 35篇 |
2004年 | 28篇 |
2003年 | 37篇 |
2002年 | 26篇 |
2001年 | 34篇 |
2000年 | 16篇 |
1999年 | 17篇 |
1998年 | 52篇 |
1997年 | 44篇 |
1996年 | 32篇 |
1995年 | 22篇 |
1994年 | 17篇 |
1993年 | 14篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 9篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1977年 | 4篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1967年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有1069条查询结果,搜索用时 15 毫秒
131.
EM Verdegaal ST Zegveld H Beekhuizen W Bakker R van Furth 《Canadian Metallurgical Quarterly》1998,22(2):215-227
Four mouse vomeronasal receptors (mV1Rs) have been isolated by similarity to rat vomeronasal receptor (V1R) motifs. The four mV1Rs identified in this study are members of two distinct subfamilies. Specific in situ hybridization probes (ISH) derived from the 3' non-coding regions of the mV1R genes, were used to detect expression of a single receptor and probes from the homologous coding regions were used to detect expression of subfamily members. The ISH results showed that the mV1Rs expressing neurons were scattered in the middle/upper layer of the vomeronasal organ (VNO) sensory epithelium in serial VNO sections but were excluded from the deeper layers of the VNO sensory epithelium and these neurons were found to co-express the mRNA for the G-protein Galphai2, and were distinct from the deeper layers of the VNO sensory epithelium where the mRNA for Galphao positive neurons was located. 相似文献
132.
Johanna Tomann 《火与材料》1993,17(4):185-190
Different types of floor coverings were tested using three different methods: the Cone Calorimeter (ISO 5660), the Nordtest floor covering test NT FIRE 007 and the German Radiant Panel Method (DIN 4102 Teil 14). The results of the comparisons between both flame spread and smoke production are given. Some correlation is found between the results of the Cone Calorimeter and the NT FIRE 007. Between other methods, no correlations seem to exist. 相似文献
133.
sec-Dodecyl ethers of ethyleneglycol, 2-chloroethanol, and 1,3-dichloro-2-propanol have been prepared by reacting 1-dodecene
with the corresponding substituted alcohol in the presence of BF3 as a catalyst.
The addition of ethyleneglycol to 1-dodecene proceeds best in the presence of a reaction solvent (e.g., nitromethane), which
suppresses side reactions. The resulting ethers consist almost exclusively of the mono-sec-dodecyl derivatives. The maximum
yield was about 50 mol% on dodecene intake and 75%m on converted ethyleneglycol.
The addition of 2-chloroethanol and 1,3-dichloro-2-propanol to dodecene can easily be conducted without a reaction solvent;
yields are 77 and 67 mol% respectively on 1-dodecene intake. A reaction scheme for the addition of ethyleneglycol to 1-dodecene
is proposed. 相似文献
134.
J Haan C Van Broeckhoven CM van Duijn E Voorhoeve F van Harskamp JC van Swieten ML Maat-Schieman RA Roos E Bakker 《Canadian Metallurgical Quarterly》1994,36(3):434-437
In 31 symptomatic and 5 asymptomatic carriers of the amyloid precursor protein (APP) gene codon 693 mutation, 10 family members without mutation, and 5 carriers of the APP gene codon 692 mutation (3 with early-onset Alzheimer dementia, 2 with cerebral hemorrhage), a high frequency of the apolipoprotein E epsilon 4 allele was found. Age at onset, age at death, occurrence of dementia, and number of strokes did not differ between APP gene mutation carriers with or without epsilon 4 allele, showing that the clinical expression of these APP mutations is not influenced by the apolipoprotein E gene. 相似文献
135.
136.
M Bakker J Renes A Groenhuijzen P Visser H Timmer-Bosscha M Müller HJ Groen EF Smit EG de Vries 《Canadian Metallurgical Quarterly》1997,73(3):362-366
While a large body of literature depicting relationships between depression or stress and immunity exists, few such studies have dealt with children, and none investigated myeloid cell-derived immunity. We investigated both phagocytosis and bactericidal activity against Staphylococcus aureus in children with major depressive disorder (MDD). We found that both MDD and stress influence the bactericidal but not the phagocytic activity of polymorphonuclear leukocytes. The data support the existence of psychobiologic effects in children and suggest possible mechanisms by which depression and stress may affect health. 相似文献
137.
Novel spin-glass alloys were synthesized by milling intermetallic compounds and also by milling mixtures of crystalline elemental powder in a high-energy ball mill.Spin glass behaviour was found in amorphous Co2Ge,which was amorphised by milling in mechanically disordered crystalline GdAl2 in ball-milled crystalline and amorphous CoZr,and in mechanically alloyed Co-Cu,which formed a supersaturated f.c.c.solid solution.All these materials are binary alloys and tlie concentration of the magnetic element is high,which makes them novel types of spin glasses.It is shown that ball milling may not only lead to structural metallic glasses,but can also generate the magnetic pendant of a structural glass,namely the spin glass. 相似文献
138.
Continuous infusion of chemotherapy is one of the developments to try to improve the treatment of metastatic cancer. There is a sound theoretical rationale to deliver cytotoxic drugs as a continuous infusion. Furthermore, the development of reliable venous access devices and portable infusion pumps enables patients to be treated in an ambulatory setting. This review focuses on the continuous infusion of the most frequently used drugs: 5-fluorouracil (5-FU) and fluorodeoxyuridine (FUDR). An overview is given of both preclinical studies and studies in humans. Continuous infusion of 5-FU and FUDR has proven to be feasible in all studies. However, the results (response rate and especially survival) are rather disappointing. So far, continuous infusion of cytostatic drugs can still be considered as an experimental procedure. Whether protracted, intermittent of circadian modulated continuous infusion is the optimal treatment schedule has still to be proven in future studies. Furthermore, studies are needed to demonstrate whether dose intensity for most tumours is important for treatment outcome. Also, studies are needed to investigate quality of life and economic issues. 相似文献
139.
140.
Conducted 3 experiments in which a total of 131 light- and dark-reared (LR and DR) male hooded rats were given sensory preconditioning (SPC). In each experiment, Ss were presented with 2 stimuli either paired or unpaired, followed by conditioning to 1 and extinction on the other. 2 auditory stimuli were used in Exp. I. SPC was found for both LR and DR Ss, with no significant difference due to rearing condition either in acquisition or in the SPC test. In Exp. II, light and tone were employed; SPC was demonstrated and was more effective for LR than DR Ss. In Exp. III, rectangle stimuli were employed. The effect of SPC was evidenced in LR Ss; however, performance of DR Ss was not significantly different from that of controls. Results are discussed in terms of the effect of early visual deprivation on information-processing mechanisms. (27 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献