全文获取类型
收费全文 | 872篇 |
免费 | 12篇 |
专业分类
电工技术 | 16篇 |
化学工业 | 171篇 |
金属工艺 | 19篇 |
机械仪表 | 16篇 |
建筑科学 | 10篇 |
能源动力 | 37篇 |
轻工业 | 53篇 |
石油天然气 | 1篇 |
无线电 | 71篇 |
一般工业技术 | 151篇 |
冶金工业 | 264篇 |
原子能技术 | 25篇 |
自动化技术 | 50篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 15篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 12篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 4篇 |
2014年 | 10篇 |
2013年 | 27篇 |
2012年 | 38篇 |
2011年 | 66篇 |
2010年 | 33篇 |
2009年 | 18篇 |
2008年 | 33篇 |
2007年 | 31篇 |
2006年 | 25篇 |
2005年 | 21篇 |
2004年 | 29篇 |
2003年 | 16篇 |
2002年 | 24篇 |
2001年 | 10篇 |
2000年 | 11篇 |
1999年 | 20篇 |
1998年 | 116篇 |
1997年 | 65篇 |
1996年 | 41篇 |
1995年 | 25篇 |
1994年 | 24篇 |
1993年 | 18篇 |
1992年 | 12篇 |
1991年 | 8篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 8篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1975年 | 4篇 |
1972年 | 2篇 |
1971年 | 3篇 |
排序方式: 共有884条查询结果,搜索用时 0 毫秒
71.
H Takechi H Onoe H Shizuno E Yoshikawa N Sadato H Tsukada Y Watanabe 《Canadian Metallurgical Quarterly》1997,230(1):17-20
Foreign body (FB) injury from aspiration or ingestion is a common pediatric health problem. Diagnosis relies on clinical judgment plus medical history, physical examination, and radiographic evaluation. A multi-institutional review of 1269 FB events revealed that 85% were correctly diagnosed following a single physician encounter. However, 15% of the children had an elusive diagnosis (>1 week), despite previous evaluation. Delays in diagnosis were seven times more likely to occur in aspirations than in ingestions. Secondary injuries (e.g., pneumonia and atelectasis) occurred in 13% of airway FBs but in only 1.7% of esophageal FBs. Plain radiographs were used in 82% of children, and special studies (e.g., fluoroscopy) in only 7%. We conclude that diagnosis of FB injury in children is frequently achieved at the initial evaluation but that continued surveillance by follow-up visits to health care facilities from parents and other caretakers is important, to reduce pulmonary injuries. 相似文献
72.
SD Detera-Wadleigh JA Badner T Yoshikawa AR Sanders LR Goldin G Turner DY Rollins T Moses JJ Guroff D Kazuba ME Maxwell HJ Edenberg T Foroud D Lahiri JI Nurnberger OC Stine F McMahon DA Meyers D MacKinnon S Simpson M McInnis JR DePaulo J Rice A Goate ES Gershon 《Canadian Metallurgical Quarterly》1997,74(3):254-262
73.
Sakaji I. Kasahara M. Ishida Y. Yoshikawa M. Nitta T. Matsushima Y. Iwatani Y. Yoshimoto A. Suzuki T. 《Hemodialysis international. International Symposium on Home Hemodialysis》2005,9(1):76-76
Purpose: Performed free coagulant hemodialysis to patients having hemorrhage with the hope to avoid aggravation of bleeding caused by anticoagulant agent from dialysis. Method: Examined 19 cases of patients with bleeding tendency, whether it is possible to perform free coagulant hemodialysis by using PAES membrane, EVAL membrane, PS membrane, Cellulose triacetate membrane and Vitamin‐E modified‐dialysis membrane. Result: With PAES membrane, the result showed a non‐ blockade rate of 91% after four hours and 100% after two hours. Therefore, blockade was prevented with a fairly high rate. In cases of blockade, most of them were possibly avoidable with a little contrivance as the reason were lack of establish blood flow rate, faulty position of a needle, etc. Conclusions: By using PAES membrane, it was possible to perform free coagulant hemodialysis. In order to completely have no blockade of blood lines in the future, we must strive further on. 相似文献
74.
Hara T. Fukuda K. Kanazawa K. Shibata N. Hosono K. Maejima H. Nakagawa M. Abe T. Kojima M. Fujiu M. Takeuchi Y. Amemiya K. Morooka M. Kamei T. Nasu H. Chi-Ming Wang Sakurai K. Tokiwa N. Waki H. Maruyama T. Yoshikawa S. Higashitani M. Pham T.D. Yupin Fong Watanabe T. 《Solid-State Circuits, IEEE Journal of》2006,41(1):161-169
An 8-Gb multi-level NAND Flash memory with 4-level programmed cells has been developed successfully. The cost-effective small chip has been fabricated in 70-nm CMOS technology. To decrease the chip size, a one-sided pad arrangement with compacted core architecture and a block address expansion scheme without block redundancy replacement have been introduced. With these methods, the chip size has been reduced to 146 mm/sup 2/, which is 4.9% smaller than the conventional chip. In terms of performance, the program throughput reaches 6 MB/s at 4-KB page operation, which is significantly faster than previously reported and very competitive with binary Flash memories. This high performance has been achieved by the combination of the multi-level cell (MLC) programming with write caches and with the program voltage compensation technique for neighboring select transistors. The read throughput reaches 60 MB/s using 16I/O configuration. 相似文献
75.
The inhibitory effects of a potent nitric oxide (NO) synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME), on 2-deoxy-D-glucose (2-DG)-induced hyperglycemia were investigated in rats. L-NAME significantly inhibited 2-DG-induced hyperglycemia, although N(G)-nitro-D-arginine methyl ester (D-NAME) did not affect it. A similar NO synthase inhibitor, N(G)-monomethyl-L-arginine (L-NMMA), also inhibited 2-DG-induced hyperglycemia. The antagonistic effects of L-NAME are unrelated to the cholinergic system, since the muscarinic receptor antagonist scopolamine did not affect 2-DG-induced hyperglycemia. The neuronal NO synthase inhibitor 7-nitroindazole (7-NI) did not reduce 2-DG-induced hyperglycemia, but rather enhanced it. Our results suggest that NO may be involved in glucose homeostasis and that the inhibitory effects of L-NAME on 2-DG-induced hyperglycemia are not related to muscarinic receptors or neuronal NO synthase. 相似文献
76.
Supachai Ngamsinlapasathian Thammanoon Sreethawong Yoshikazu Suzuki Susumu Yoshikawa 《Solar Energy Materials & Solar Cells》2006,90(14):2129-2140
The effects of indium tin oxide (ITO) and ITO/SnO2 conducting substrates on photovoltaic properties of dye-sensitized solar cells (DSCs) using nanocrystalline TiO2 were studied. The decrease in fill factor of the DSCs was correlated to the increase in resistance of conducting substrate. The heat stability of ITO conducting glass was improved by depositing SnO2 on ITO layer. The efficiency of the cells using double layered ITO/SnO2 substrate remarkably increased comparing with that of the cells using ITO substrates. It is worth mentioning that increasing in sintering time, which enhanced the electronic contact between substrate and TiO2, also modified the cell performance of MP-TiO2 cells. Our experimental finding suggests that 3000 Å ITO substrate, which was covered by 1000 Å SnO2 layer, exhibited the best properties for the DSCs. 相似文献
77.
Scintillation properties of Tm-doped Lu3Al5O12 single crystals 总被引:1,自引:0,他引:1
Makoto Sugiyama Yutaka Fujimoto Takayuki Yanagida Daisuke Totsuka Yuui Yokota Akira Yoshikawa 《Optical Materials》2011,34(2):439-443
Using the micro-pulling-down (μ-PD) method, Tm-doped Lu3Al5O12 (Tm:LuAG) single crystals were grown to examine their scintillation properties. In transmittance spectra, they exhibited about 80% transparency in the wavelengths longer than 320 nm and five absorption lines due to Tm3+ 4f–4f transitions were observed. 241Am α-ray excited radioluminescence spectra were measured and intense 4f–4f emission peaks were observed with the host emission. When excited by 137Cs γ-Ray to obtain pulse height spectra, Tm 1% doped LuAG showed the highest light yield coupled with a photomultiplier (PMT) or a silicon avalanche photodiode (Si-APD). The light yield was estimated to be 5800 and 7300 photons/MeV for PMT and Si-APD, respectively. Decay time profiles consist of two exponential components and the fast and slow components are considered to be attributed to the host and the combination of the host and Tm3+ 4f–4f emission, respectively. 相似文献
78.
Makoto Sugiyama Yutaka FujimotoTakayuki Yanagida Yuui YokotaJan Pejchal Yuki FuruyaHidehiko Tanaka Akira Yoshikawa 《Optical Materials》2011,33(6):905-908
Nd 0.1%, 0.5%, 1% and 3% doped Lu3Al5O12 (Nd:LuAG) single crystals were grown in the nitrogen atmosphere by the micro-pulling down (μ-PD) method. The grown crystals had a single-phase confirmed by powder XRD analysis. In absorption spectra, some weak absorption lines due to Nd3+ 4f-4f transitions were observed and their intensity increased with the increase of Nd concentration. When excited by 241Am α-ray, a broad emission peak due to defects in the host lattice at 320 nm and some sharp lines due to Nd3+ 4f-4f transitions at wavelength longer than 400 nm were observed. The decay time profiles of Nd:LuAG under γ-ray excitation were well approximated by two exponential function of 340-760 ns and 3-5 μs for each sample. By pulse height measurement using 137Cs, Nd 0.5%:LuAG showed the highest light yield of 7600 ± 760 photons/MeV. 相似文献
79.
Kumaki Y Ogawa M Hirano T Yoshikawa K Iwasawa N Yagi T Hakamata W Oku T Nishio T 《Journal of Bioscience and Bioengineering》2011,111(2):134-139
The chromosomal DNA of the syntrophic thermophile Symbiobacterium thermophilum contains open reading frames of the genes encoding family M42 aminopeptidases, Pep1079, Pep1080, and Pep1081. To characterize these peptidases, the genes were cloned into Escherichia coli and overexpressed. Our experiments using the recombinant proteins confirmed that Pep1079, Pep1080, and Pep1081 are components of arginyl or lysinyl aminopeptidases that require Co2+ for enzymatic activity. Coexistence of Pep1079 and Pep1080 is necessary for expressing high peptidase activity. Pep1081 enhances the activity of Pep1079 and Pep1080. 相似文献
80.
Yoshikawa M Seki H Inoue K Matsuda K Tanahashi Y Sako H Nanen Y Kato M Kimoto T 《Applied spectroscopy》2011,65(5):543-548
We used Fourier transform infrared (FT-IR) spectroscopy to characterize silicon dioxide (SiO(2)) films on a 4H-SiC(0001) Si face. We found that the peak frequency of the transverse optical (TO) phonon in SiO(2) films grown on a 4H-SiC substrate agrees well with that in SiO(2) films grown on a Si substrate, whereas the peak frequency of the longitudinal optical (LO) phonon in SiO(2) films on a 4H-SiC substrate is red-shifted by approximately 50 cm(-1) relative to that in SiO(2) films on a Si substrate. We concluded that this red-shift of the LO phonon is mainly caused by a change in inhomogeneity due to a decrease in density in the SiO(2) films. Furthermore, cathodoluminescence (CL) spectroscopy results indicated that the channel mobility of the SiC metal-oxide-semiconductor field-effect transistor (MOSFET) decreases roughly in proportion to the increase in the intensity of the CL peak at 460 and 490 nm, which is attributed to the increase in the number of oxygen vacancy centers (OVCs). FT-IR and CL spectroscopies provide us with a large amount of data on OVCs in the SiO(2) films on a 4H-SiC substrate. 相似文献