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排序方式: 共有1213条查询结果,搜索用时 312 毫秒
931.
932.
An acidophilic heterotrophic bacterium, designated as HIB4, having the ability to oxidize ferrous ion was newly isolated from a sample of an enrichment culture for iron-oxidizing bacteria, using the modified washed agarose/yeast extract (WAYE) medium with ferrous sulphate. The isolate HIB4 was an acidophilic, heterotrophic, mesophilic and gram-positive bacterium. Phylogenetically, it was classified under the genus Alicyclobacillus and was the closest to Alicyclobacillus disulfidooxidans SD-11 with 99.7% 16S rDNA homology. It grew and oxidized ferrous ion in the medium containing 0.02% (w/v) yeast extract. Yeast extract was an essential substrate for this bacterium because it could not grow or oxidize ferrous ion without yeast extract. However, a higher concentration of yeast extract inhibited the growth of HIB4, so that the optimum concentration of yeast extract for this bacterium to grow was 0.02% (w/v) at 0.08 mol/l of ferrous ion. On the other hand, ferrous ion oxidation occurred almost at the end of the bacterium's logarithmic growth phase and the isolate was able to grow without ferrous ion. These results denote that HIB4 did not obtain any energy from the ferrous ion oxidation and that HIB4 is an obligate heterotrophic and aerobic bacterium even though it oxidized ferrous ion. Also, HIB4 could not utilize any organic compounds, among the several organic chemicals used in this study, as a carbon source except yeast extract. These characteristics were completely different from these of A. disulfidooxidans SD-11 so that HIB4 might be a different species. 相似文献
933.
934.
Yuji Hiruma Kota Marumo Rintaro Aoyagi Hajime Nagata Tadashi Takenaka 《Journal of Electroceramics》2008,21(1-4):296-299
Bismuth potassium titanate, (Bi1/2K1/2)TiO3 (BKT), ceramics were prepared by the hot-pressing (HP) method without dopant and with dopants of Bi2O3, La2O3 and MnCO3. The relative density of BKT ceramics hot-pressed at 1,060 and 1,080 °C (hereafter abbreviated to BKT-HP1060°C and BKT-HP1080°C) and x mass% Bi2O3, La2O3 and MnCO3 doped BKT ceramics hot-pressed at 1,060 °C (hereafter abbreviated as BKTBix; x?=?0.1–0.6, BKTLax; x?=?0.1–0.6 and BKTMnx; x?=?0.1–0.3) were all higher than 97%. In this study, the ferroelectric properties of BKT ceramics were successfully obtained, and the remanent polarization P r and coercive field E c of BKT-HP1080°C were 22.2 μC/cm2 and 52.5 kV/cm, respectively. A small amount of La tends to increase P r, and the P r of BKTLa0.1 was 19.2 μC/cm2. The piezoelectricities were improved to optimize poling conditions, and the electromechanical coupling factor k 33 and piezoelectric constant d 33 of BKT-HP1080°C were 0.34 and 82.8 pC/N, respectively. 相似文献
935.
Thermosensitive and superabsorbent polymer hydrogels were synthesized by copolymerization of three kinds of tri‐n‐alkyl vinylbenzyl phosphonium chlorides (TRVB) with different lengths of alkyl chains, N‐isopropylacrylamide (NIPAAm), and N,N′‐methylenebisacrylamide (MBAAm). The water‐absorption ability and antibacterial activity of the hydrogels against Staphylococcus aureus (S. aureus) were investigated. The water content of TRVB–NIPAAm–MBAAm copolymers decreased with increasing temperature and increased with increasing phosphonium groups in the copolymers, while it decreased with increasing chain length of the alkyl groups in the phosphonium groups as well as with an increasing degree of crosslinking in the copolymers. The TRVB–NIPAAm–MBAAm copolymers with a higher TRVB content in the copolymers exhibited higher antibacterial activity against S. aureus, but decreased with increasing chain length of alkyl groups in phosphonium groups. The TRVB–NIPAAm–MBAAm copolymers exhibited the highest antibacterial activity at 30°C against S. aureus in deionized water. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 115–124, 2001 相似文献
936.
Shigemitsu Okabe Masanori Koto Tadashi Koshizuka Susumu Nishiwaki Nobuyuki Takahashi Toshiyuki Saida Satoru Yanabu 《Electrical Engineering in Japan》2001,135(1):24-32
High lightning overvoltages do not appear in underground substations connected to transmission cables. Consequently, it is very important to thoroughly investigate switching overvoltages and to achieve rational insulation coordination for apparatus installed in such underground substations. This paper discusses the occurrence of steep fronts at transient recovery voltages (TRV) appearing at circuit breakers when the inrush currents of transformers are interrupted. Caused by a steep front at the TRV, reignitions occur at circuit breakers, resulting in the generation of high overvoltages with high frequencies. The overvoltages are among the highest switching overvoltages appearing at the terminal of a transformer. The authors clarified the mechanism of the generation of steep fronts at TRV by means of EMTP analysis, as well as by carrying out tests in a high‐power laboratory. © 2001 Scripta Technica, Electr Eng Jpn, 135(1): 24–32, 2001 相似文献
937.
Masaru Isozaki Toshiyuki Hikosaka Yoshifumi Hatakeyama Mamoru Yamada Tadashi Morita 《Electrical Engineering in Japan》2000,130(1):68-75
Advanced closing switch for three‐phase short‐circuit test was developed for very fast current limiter using power electronics devices. The conventional short‐circuit test method was used for verification of the current interrupting device with longer time duration to interrupt fault current after the separation of contacts. In the conventional short‐circuit test method, a deviation of the closing time between each phase closing switch with a mechanical driving was regulated so that the breaking performance of the conventional switching device could be examined. However, in the new current limiter with very short fault current interruption time, the deviation time between each phase must be reduced less than the regulated time by the conventional test method. For this purpose, the advanced closing switch for three‐phase short‐circuit test method was developed. In the advanced test method, power electronics devices were used for the initiation of three‐phase short‐circuit fault. Results of the short‐circuit test showed that the advanced circuit had very small deviation time between the initiation of each phase fault. Also, the very fast current limiter with power electronics devices was shown to have an intended interrupting performance. © 1999 Scripta Technica, Electr Eng Jpn, 130(1): 68–75, 2000 相似文献
938.
Masayuki Nagai Yasuaki Shibuya Tadashi Nishino Tatsuya Saeki Hitoshi Owada Kimihiro Yamashita Takao Umegaki 《Journal of Materials Science》1991,26(11):2949-2953
Calcium orthophosphate powders with various Ca/P ratios were prepared by a wet process, employing CaCO3 and H3PO4 as starting materials. After they were calcined and pressed to form pellets, they were fired at various temperatures ranging from 800 to 1200 °C. The samples at various stages were examined by X-ray diffraction and SEM, The a.c. electrical conductivity was measured for a series of samples. For some of the samples, the d.c. electrical conductivity and electromotive force were also measured. The samples showed relatively high conductivity (4×10–5 S cm–1 at 800 °C). With respect to the tricalcium orthophosphate with nearly stoichiometric composition, the predominant charge carrier at 800 °C was presumed to be an ion although it is not identified at the moment. 相似文献
939.
The specific heat under saturated vapor pressure of pure 4He and of six 3He-4He mixtures up to X = 0.545 was measured in the temperature range 3 × 10–6 <¦T-T
¦ <10–2 K. The critical exponents and along the path = are independent of X up to X = 0.545, where (= 3 – 4) is the difference between chemical potentials. If we take account of higher order terms, the exponent (= ) and the amplitude ratio A
/A are independent of X up to X = 0.545. The values of and A
/A are –0.023 and 1.090, respectively. The critical-tricritical crossover effect was observed for X = 0.545 and the boundary of crossover region closest to the critical region was at /T
= (1–2) × 10–4, where is the distance ¦T – T
¦ along the path =
. This value is in good agreement with the estimated value by Riedel et al. But, remarkably, in the case of X = 0.439 this effect was not observed. 相似文献
940.
The optical yields of the enantio-differentiating hydrogenation of aromatic β-ketoesters over tartaric acid-modified Raney nickel were found to be lower than those of aliphatic γ-ketoesters when the aromatic group is conjugated to the ketone moiety. The reason for the reduced optical yield is due to
the lower intrinsic enantio-differentiation compared to the aliphatic substrate.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献