全文获取类型
收费全文 | 2005篇 |
免费 | 17篇 |
国内免费 | 3篇 |
专业分类
综合类 | 3篇 |
化学工业 | 26篇 |
金属工艺 | 4篇 |
机械仪表 | 11篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
能源动力 | 4篇 |
轻工业 | 5篇 |
水利工程 | 13篇 |
石油天然气 | 6篇 |
无线电 | 5篇 |
一般工业技术 | 20篇 |
冶金工业 | 1901篇 |
原子能技术 | 8篇 |
自动化技术 | 13篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 3篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 5篇 |
2012年 | 2篇 |
2011年 | 5篇 |
2010年 | 6篇 |
2009年 | 7篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 8篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 56篇 |
1998年 | 664篇 |
1997年 | 299篇 |
1996年 | 224篇 |
1995年 | 112篇 |
1994年 | 99篇 |
1993年 | 119篇 |
1992年 | 11篇 |
1991年 | 24篇 |
1990年 | 29篇 |
1989年 | 33篇 |
1988年 | 33篇 |
1987年 | 27篇 |
1986年 | 15篇 |
1985年 | 14篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 12篇 |
1980年 | 13篇 |
1978年 | 1篇 |
1977年 | 24篇 |
1976年 | 103篇 |
1956年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有2025条查询结果,搜索用时 15 毫秒
1.
Nazmul Abedin Khan Biswa Nath Bhadra Suk Woo Park Yong‐Su Han Sung Hwa Jhung 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(12)
Polyanilines (pANIs), loaded with phosphotungstic acid (PTA), are pyrolyzed to get WO3 or W2N (≈6 and ≈7 nm, respectively), which is well‐dispersed on pANI‐derived porous carbons (pDCs). Depending on the pyrolysis temperature, WO3/pDC, W2N/pDC, or W2N‐W/pDCs could be obtained selectively. pANI acts as both the precursor of pDC and the nitrogen source for the nitridation of WO3 into W2N during the pyrolysis. Importantly, W2N could be obtained from the pyrolysis without ammonia feeding. The obtained W2N/pDC is applied as a heterogeneous catalyst for the oxidative desulfurization (ODS) of liquid fuel for the first time, and the results are compared with WO3/pDC and WO3/ZrO2. The W2N/pDC is very efficient in ODS with remarkable performance compared with WO3/pDC or WO3/ZrO2, which is applied as a representative ODS catalyst. For example, W2N/pDC shows around 3.4 and 2.7 times of kinetic constant and turnover frequency (based on 5 min of reaction), respectively, compared to that of WO3/ZrO2. Moreover, the catalysts could be regenerated in a facile way. Therefore, W2N/pDC could be produced facilely from pyrolysis (without ammonia feeding) of PTA/pANI, and W2N, well‐dispersed on pDC, can be suggested as a very efficient oxidation catalyst for the desulfurization of liquid fuel. 相似文献
2.
介绍了真空缓冷炉渣的工艺矿物学特性。试验研究结果表明,该炉渣属于中等可碎性偏难,硬度系数在8 ̄16之间,在磨矿细度为-0.016mm占89%时,粗、扫选抛尾粗精矿再磨再选,以Z-200、SN-9和丁胺为混合捕收剂,最终得到铜精矿产率为4.59%,精矿含铜23.48%,含金5.8g/t,铜回收率为83.70%;尾矿含铜0.22%,含金0.18g/t。 相似文献
3.
A BABANEJHAD M HASHEMI Y RAHMATALLAHPUR SH A NOZAD 《Bulletin of Materials Science》2012,35(4):561-566
The present work aims to study effect of lactic acid concentration as complexing agent on surface roughness and nucleation morphology of electroless N?CP deposition. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) have been used to study nucleation morphology and surface roughness of deposition. Deposition process started at some initial priority growing centres independently distributed on the substrate. We found that the morphology and surface roughness of deposition strongly depends on the complexing agent concentration. Morphology of initial deposited centres with no concentration of lactic acid was in coniform structure. By increasing the complexing agent concentration, the structure of initial growing centres changed from coniform to nodular shape and the surface roughness of depositions decreased. 相似文献
4.
JK Han HJ Jang BI Choi SH Kim TK Kim HJ Won YI Kim SY Cho 《Canadian Metallurgical Quarterly》1999,34(2):99-108
RATIONALE AND OBJECTIVES: The authors sought to correlate the radiologic findings of hepatobiliary fascioliasis with pathologic features. METHODS: Serial ultrasound, computed tomography (CT), and magnetic resonance findings in seven rabbits with experimentally induced fascioliasis were obtained every other week. Direct cholangiogram was also obtained after the rabbits were killed. Radiology-pathology correlation was done in specimens. RESULTS: In the parenchymal phase (an acute phase of parenchymal invasion of a larva), CT showed subcapsular clustered areas of low attenuation. Magnetic resonance appearance was similar in shape but better than CT in characterizing the hemorrhagic nature of the lesion. Ultrasound findings were nonspecific in this phase. In the ductal phase (a stationary phase after residing in the bile duct), CT showed dilatation of central ducts with symmetric periportal hypoattenuation (periportal tracking). Magnetic resonance could not depict mild ductal dilatation. Ultrasound was most valuable in demonstrating the moving worm within the dilated duct. Pathologically, the hepatic parenchymal lesions consisted of a cluster of eosinophilic granulomas with hemorrhagic change (migratory tract of the flukes). Ductal changes were observed predominantly in the central bile ducts. Periportal lymphangiectasia was also noted. CONCLUSIONS: Computed tomography or magnetic resonance can demonstrate the characteristic evolutionary pattern of fascioliasis that reflects the unique life cycle of Fasciola hepatica. The role of ultrasound, although limited in the parenchymal phase, was most useful in the ductal phase in that it demonstrated the moving worms themselves. 相似文献
5.
6.
SH Wong Y Xu T Zhang G Griffiths SL Lowe VN Subramaniam KT Seow W Hong 《Canadian Metallurgical Quarterly》1999,10(1):119-134
Syntaxin 1, synaptobrevins or vesicle-associated membrane proteins, and the synaptosome-associated protein of 25 kDa (SNAP-25) are key molecules involved in the docking and fusion of synaptic vesicles with the presynaptic membrane. We report here the molecular, cell biological, and biochemical characterization of a 32-kDa protein homologous to both SNAP-25 (20% amino acid sequence identity) and the recently identified SNAP-23 (19% amino acid sequence identity). Northern blot analysis shows that the mRNA for this protein is widely expressed. Polyclonal antibodies against this protein detect a 32-kDa protein present in both cytosol and membrane fractions. The membrane-bound form of this protein is revealed to be primarily localized to the Golgi apparatus by indirect immunofluorescence microscopy, a finding that is further established by electron microscopy immunogold labeling showing that this protein is present in tubular-vesicular structures of the Golgi apparatus. Biochemical characterizations establish that this protein behaves like a SNAP receptor and is thus named Golgi SNARE of 32 kDa (GS32). GS32 in the Golgi extract is preferentially retained by the immobilized GST-syntaxin 6 fusion protein. The coimmunoprecipitation of syntaxin 6 but not syntaxin 5 or GS28 from the Golgi extract by antibodies against GS32 further sustains the preferential interaction of GS32 with Golgi syntaxin 6. 相似文献
7.
Numerical Study of Three Different Approaches to Simulate Nanofluids Flow and Heat Transfer in a Microtube 下载免费PDF全文
In this paper, Eulerian, mixture and single phase models are used to simulate laminar and turbulent forced convective flow of SiO2‐EG nanofluid in a microtube. The comparison between the three approaches and other formula shows that for laminar and turbulent flow the single phase model shows higher heat transfer enhancement and is more precise in comparison to the other Eulerian and mixture models. 相似文献
8.
SH Bernstein J Fay S Frankel N Christiansen MR Baer C Jacobs C Blosch R Hanna G Herzig 《Canadian Metallurgical Quarterly》1999,43(2):141-144
PURPOSE: The recombinant human interleukin-1 receptor (rhu IL-1R) is a soluble truncated form of the type 1 full-length membrane-bound receptor that binds IL-1 with identical affinity to that of the membrane form. As such, it may have clinical potential by sequestering IL-1, thereby preventing it from binding to its membrane-bound receptor and eliciting a biological effect. As IL-1 has been shown to regulate leukemic cell proliferation in an autocrine fashion, a phase I trial of rhu IL-1R was conducted in patients with relapsed and refractory acute myeloid leukemia (AML). METHODS: The study group comprised 11 patients who were sequentially treated on one of three dose levels, receiving a single intravenous (i.v.) bolus dose on day 1 followed by 13 days of daily subcutaneous (s.c.) injections with the option of an additional 14 days of treatment if a response of stable disease or better was achieved. Dose level 1 i.v. bolus 500 microg/m2, s.c. dose 250 microg/m2 per day (five patients); dose level 2 i.v. bolus 1000 microg/m2, s.c. dose 500 microg/m2 per day (three patients); dose level 3 i.v. bolus 2000 microg/m2, s.c. dose 1000 microg/m2 per day (three patients). Owing to limited drug availability, the study was designed to only examine these three dose levels. RESULTS: rhu IL-IR was well tolerated. There was no grade 3 or 4 non-hematological toxicity related to the study drug and the maximum tolerated dose was not reached. No IL-1R-blocking antibodies developed during the course of the study. Serum levels of IL-1beta, IL-6 and TNF were undetectable before, during and after rhu IL-IR administration. The terminal half-life after i.v. dosing was at least 7-12 h, and after s.c. dosing 2-4 days. Serum levels of rhu IL-1R up to 360- and 25-fold those of pretreatment levels were achieved after i.v. and s.c. dosing respectively. No patient had a complete, partial or minor response to treatment; four had stable disease and seven had progressive disease. CONCLUSIONS: rhu IL-1R therapy was safe but did not have any apparent antileukemic effect at the doses administered. 相似文献
9.