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111.
A new one-atomic layer ZrO2/ZSM-5 hybrid catalyst was prepared by using the repeated reactions between Zr(OC2H5)4 and of the OH groups of the external surfaces of ZSM-5, followed by calcination. The one-atomic layer ZrO2 attached on the ZSM-5 surface was characterized by means of X-ray diffraction, X-ray fluorescence and EXAFS. The ZrO2 overlayer is suggested to epitaxially grow on the ZSM-5(001) plane in a [111] direction of tetragonal ZrO2. The one-atomic layer ZrO2/ZSM-5 is a unique catalyst which produces selectively isopentane from CH3OH. 相似文献
112.
113.
114.
MU Ferreira Q Liu M Kimura BT Ndawi K Tanabe F Kawamoto 《Canadian Metallurgical Quarterly》1998,84(6):1286-1289
Allelic diversity in the merozoite surface protein-1 (MSP-1) of Plasmodium falciparum, a major malaria vaccine candidate, was examined in clinical isolates from holoendemic northern Tanzania. The variable blocks 2, 4a, 4b, 6, and 10 of the MSP-1 gene were typed by allelic type-specific polymerase chain reaction. Twenty-four possible MSP-1 gene types were defined as unique combinations of allelic types detected in each variable block. Thirteen gene types were identified, and 187 P. falciparum populations were fully typed among 79 isolates. In contrast with recent findings in Vietnam, we were unable to detect nonrandom associations between allelic types in the typed variable blocks. Most patients (60%) harbored more than 1 genetically distinct parasite population (average: 2.37 populations per isolate) and, in 1 patient, 6 different versions of this single-copy gene were found. Statistical analysis suggests that parasites carrying different MSP-1 gene types are not independently distributed in the host population. The epidemiological consequences of these findings are discussed. 相似文献
115.
H Yoshida H Enomoto M Miyauchi K Takenaga M Tanabe N Ohnuma S Sakiyama M Tagawa 《Canadian Metallurgical Quarterly》1998,12(5):1067-1071
OBJECTIVE: Our purpose was to evaluate the clinical utility of serum uric acid measurements in the hypertensive diseases of pregnancy. STUDY DESIGN: We performed a nested case-control study to assess the clinical utility of serum uric acid measurements in women with hypertensive diseases of pregnancy. We identified 344 women who had serum uric acid measurements at term and categorized them into five diagnostic groups according to definitions of hypertensive diseases in pregnancy published by the National Working Group on Hypertension in Pregnancy: transient hypertension of pregnancy (n = 69), preeclampsia (n = 130), chronic hypertension (n = 23), chronic hypertension with superimposed preeclampsia (n = 29), and normal (n = 93). We compared the mean uric acid concentration for each group with use of a one-way analysis of variance and Scheffe's post hoc test and calculated the sensitivities and specificities in diagnosing preeclampsia as well as the likelihood ratios for serum uric acid values of 5.5, 6.0, and 6.5 mg/dl. We also examined the correlation between serum uric acid levels and several clinical outcome measures in women with hypertensive diseases of pregnancy. RESULTS: The mean serum uric acid values for women with preeclampsia (6.2 +/- 1.4 mg/dl) and transient hypertension (5.6 +/- 1.7 mg/dl) were significantly higher than those of controls (4.3 +/- 0.8 mg/dl, p < 0.05). The difference in mean serum uric acid values between women with chronic hypertension (4.9 +/- 1.0 mg/dl) and superimposed preeclampsia (5.8 +/- 1.4 mg/dl) were not statistically significant. The likelihood ratio of having preeclampsia with a serum uric acid value of 5.5 mg/dl was 1.41 in gestational hypertension of pregnancy and 2.5 in chronic hypertension. With use of a receiver-operator characteristic curve, we were unable to identify a serum uric acid value that could be used to differentiate various hypertensive diseases of pregnancy. There was a weak correlation between serum uric acid values and several clinical outcome measures of preeclampsia (r = 0.06 to 0.26). CONCLUSION: Although mean serum uric acid values are elevated in women with preeclampsia, the clinical utility of serum uric acid values in differentiating various hypertensive diseases of pregnancy appears to be limited. In the setting of chronic hypertension, however, a serum uric acid level of > or = 5.5 mg/dl could identify women with an increased likelihood of having superimposed preeclampsia. 相似文献
116.
The occurrence and fate of a herbicide CNP (2,4,6-trichlorophenyl-4′-nitrophenylether) in rivers and agricultural drainages was investigated. CNP residues in water samples were extracted by adsorption on a macroreticular XAD-2 resin column and subjected to gas chromatographic analysis using an electron capture detection after desorption from the column and concentration. The minimum detectable amount was 0.04 ng and a positive identification of CNP residue in water samples was obtained with a combined gas chromatography-mass spectrometry-computer system when 500 ng of CNP was injected. CNP residues were detected in water samples taken in June to September, and these levels were between 0.01 and 16.67 μg l−1. The maximum level was found in a sample taken on 13th July, 1977, about a month after beginning rice seedling transplantation, and the minimum level was detected on August 29th, 1977. However CNP residue levels were increased again in September because flooded water on the paddy fields was excluded. CNP was more persistent in the aquatic environment than a herbicide benthiocarb. 相似文献
117.
Even at ambient pressure and temperature TiFe and TiFe-Nb 6.8 at.% compounds display their outstanding abilities for absorbing hydrogen when cathodically polarized in an aqueous solution. Electrochemical reaction is also highly activated on electrodes made of these intermetallic compounds. This paper describes the results of electrochemical measurement and the surface properties of both TiFe and TiFe-Nb 6.8 at.% electrodes in comparison with those obtained using TiNin and TiCon (n = 1, 2, 3), emphasizing catalytic activity for the reaction of hydrogen evolution. It was concluded that the electrochemically active site of TiFe or TiFe-Nb 6.8 at.% electrode surface could be formed only after a specified area of the electrode had been covered with hydrogen of one or a few atomic layers. At the same time, this site acts as an entrance and exit for hydrogen into and out of the electrode. 相似文献
118.
H. Tsukada Z. Asaki T. Tanabe Y. Kondo 《Metallurgical and Materials Transactions B》1981,12(3):603-609
. A rectangular plate of mixed copper-iron sulfide composed of bornite (Cu5FeS4) and troilite (FeS) was oxidized in an O2-Ar mixed gas stream at 1023 to 1123 K. At the start of the oxidation, iron was preferentially oxidized with the rapid formation
of a dense Fe3O4 layer of about 10 μm thickness on the sample surface, without the evolution of SO2 gas. Following this reaction, layers of both Fe3O4 and Fe2O3 grew on the sulfide surface in accordance with the parabolic rate law. The diffusion of iron through the oxide layers was
assumed to control the oxidation rate during this stage. The effect of oxygen partial pressure on the parabolic rate constants
was minor and an apparent activation energy of 126 kJ/mol was obtained. During the later stages of the reaction, when the
sulfur activity in the inner sulfide core increased, the oxidation proceeded irregularly to the interior of the remaining
sulfide with the formation of a porous oxide and the evolution of gaseous SO2. The remaining sulfide core was found to be
a mixture of bornite (Cu5FeS4) and djurleite (Cu1.96S).
H. TSUKADA, former Graduate Student at Kyoto University 相似文献
119.
120.
Otsuka H Hirano A Nagasaki Y Okano T Horiike Y Kataoka K 《Chembiochem : a European journal of chemical biology》2004,5(6):850-855
A two-dimensional microarray of ten thousand (100 x 100) hepatocyte heterospheroids, underlaid with endothelial cells, was successfully constructed with 100 microm spacing in an active area of 20 x 20 mm on microfabricated glass substrates that were coated with poly(ethylene glycol) brushes. Cocultivation of hepatocytes with endothelial cells was essential to stabilize hepatocyte viability and liver-specific functions, allowing us to obtain hepatocyte spheroids with a diameter of 100 microm, functioning as a miniaturized liver to secret albumin for at least one month. The most important feature of this study is that these substrates are defined to provide an unprecedented control of substrate properties for modulating cell behavior, employing both surface engineering and synthetic polymer chemistry. The spheroid array constructed here is highly useful as a platform of tissue and cell-based biosensors and detects a wide variety of clinically, pharmacologically, and toxicologically active compounds through a cellular physiological response. 相似文献