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排序方式: 共有552条查询结果,搜索用时 15 毫秒
531.
SH Siddiqi LB Heifets MH Cynamon NM Hooper A Laszlo JP Libonati PJ Lindholm-Levy N Pearson 《Canadian Metallurgical Quarterly》1993,31(9):2332-2338
A multicenter study was done to investigate the accuracy and reproducibility of a method for determining the MICs of antimicrobial agents against the Mycobacterium avium complex in 7H12 broth with the BACTEC system. In phase I, with eight drugs and 10 strains, intralaboratory reproducibility was 95.7 to 100%, allowing a 1-dilution difference upon repeat testing. The results of phase II testing with 41 additional strains were consistent with those obtained in phase I, with good interlaboratory reproducibility. The radiometric method was validated by sampling and plating of the same broth cultures and determining, by the number of CFU per milliliter, the lowest drug concentration that inhibited more than 99% of the initial bacterial population. Three test concentrations of each drug and the tentative interpretation of results are proposed. Radiometric MIC determination has the potential to become the method of choice for clinical microbiology laboratories and evaluation of new agents for the treatment of M. avium infections, both pulmonary and disseminated. 相似文献
532.
Franck Cheillan Huguette Lafont Elise Termine Yolande Hamann Guy Lesgards 《Lipids》1989,24(3):224-228
A method combining enzymatic and electrochemical detection of cholesterol in biological fluids was compared with conventional
detection methods: two chromatographic methods—gas chromatography or high performance liquid chromatography—and two enzymatic
methods with colorimetric detection either by kinetic measurement or at the end of the reaction. For serum, enzymatic determination
is accurate with both colorimetric detection methods; but for bile, colorimetric detection is difficult to perform due to
interference from bile pigments. Enzymatic cholesterol determination, combined with electrochemical detection, is simpler
and gives results in good agreement with those of chromatographic methods. 相似文献
533.
Gilles Nalbone Jeannie Leonardi Elise Termine Henri Portugal Paulette Lechene Anne-Marie Pauli Huguette Lafonf 《Lipids》1989,24(3):179-186
In this study, we investigated the effect of various types of fats on heart lipid peroxidation status and on blood lipid parameters.
Rats were fed either a low-fat diet (2.2% lard plus 2.2% corn oil), a corn oil diet (17%), a salmon oil diet (12.5%) supplemented
with 4.5% corn oil, or a lard diet (15%) supplemented with 2% corn oil. All diets were supplemented with 1% cholesterol. Rats
were fed for eight weeks. When compared with the low-fat diet, the salmon oil-diet intake resulted in a lower blood cholesterol,
triglyceride and phospholipid concentrations (−50, −56 and −30%, respectively). Corn oil only tended to lower blood lipids;
this decrease was significant for triglycerides only (−40%). The hypocholesterolemic effect of salmon oil diet is even more
pronounced, if blood cholesterol values are compared with those of rats fed the lard diet. Heart lipid composition was not
affected by dietary manipulations. Fatty acid composition of cardiac phosphatidylcholines and phosphatidylethanolamines, however,
were altered by high-fat diets. In phosphatidylcholine, salmon oil induced a twelvefold decrease in the n−6/n−3 ratio and
a 26% increase in the unsaturation index. For phosphatidylethanolamine, the n−6/n−3 ratio decreased 7.7-fold and the unsaturation
index increased by 13%. A 50% decrease of the n−6/n−3 ratio was observed in animals fed the lard diet. Ultramicroscopic examination
of ventricles revealed that those of the salmon oil group significantly accumulated lipofuscin-like or ceroid material, whereas
this accumulation was barely detectable in hearts of the other groups. Seleniumdependent glutathione peroxidase activity tended
to be the highest in hearts of rats fed the salmon oil diet; this increase is significant (+36% and +54% for total and specific
activities, respectively), if values are compared with those of the rats fed the lard diet. Liver glutathione peroxidase and
heart glutathione S-transferases activities remained unchanged. These results indicate that fish oil did not lower the selenium
involved in glutathione peroxidase activity. This rules out that a deficiency in this enzyme was at the origin of heart lipofuscinosis.
Also, it is concluded that the n−6/n−3 ratio of the diet is likely more determinant in the alteration of heart lipid peroxidation
status than is the polyunsaturated/saturated ratio.
Part of this work was presented at the International Congress: “Selenium in Medicine and Biology,” Avoriaz, France, March,
15–18, 1988. 相似文献
534.
535.
536.
Cong Tam Nguyen Janos Bagi Laszlo Lakosi 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2007,262(1):75-80
The paper describes a pure neutron method for determining both Pu content and Pu isotopic composition of PuBe neutron sources by neutron coincidence technique, without using gamma-spectrometry. The new procedure based on the R/T-T relationship is a developed version of the R/T-method based on R/T-MPu calibration curve described in [C.T. Nguyen, J. Bagi, L. Lakosi, A novel method of quantitative assay of PuBe neutron sources by neutron coincidence technique, Nucl. Instr. and Meth. B 246 (2006) 409], utilizing Pu isotopic correlations; here R, T, MPu are double count rate, single count rate and total Pu content, respectively. Accuracy of the method was found to be about 2-3% and 15% for 239Pu component and Pu content, respectively. Measurement time as a function of detector efficiency is treated in detail. It is shown that in a system of frame, a transuranium neutron source can be characterized by a pair of co-ordinates [R/T, T]. 相似文献
537.
Jai Prakash Laszlo Redey Donald R. Vissers James DeGruson 《Journal of Applied Electrochemistry》2000,30(11):1229-1233
The effect of sodium iodide and sulfur additives on the performance of Na/-alumina/NaAlCl4/NiCl2/Ni cells was investigated in quasi-sealed laboratory research cells (0.5–1.0 Ah capacity) and in sealed full-size cells (4 Ah capacity). It was found that sodium iodide additive especially in combination with sulfur in Na/NiCl2 cells significantly increases the usable capacity and reduces the impedance of the Na/NiCl2 cells. It is proposed that the use of sodium iodide enhances the energy and power performance of the NiCl2 electrode by two different mechanisms. The first mechanism, iodide ion doping of the anodically formed solid NiCl2, is dominant at potentials lower than that of iodine evolution. The doping effect of the iodide ions produces a higher-capacity, lower-impedance NiCl2 layer on the positive electrode. The second mechanism, anodic formation of very reactive iodine species, is effective when the cell is cycled through the iodine evolution potential range (2.8–3.1 V vs Na). During this process, the dissolved iodine species improve electrode kinetics through liquid-phase mass transport. Use of the sodium iodide additive is safe in sealed cells, causing no over-pressurizing problems. A maximum pressure increase of only 10 kPa was detected by a pressure sensor during severe overcharge tests. 相似文献
538.
539.
Katalin Prokai-Tatrai Vien Nguyen Laszlo Prokai 《International journal of molecular sciences》2021,22(12)
Selective antagonists of thyrotropin-releasing hormone (TRH; pGlu-His-Pro-NH2), in order to enable a better understanding of this peptide’s central functions, have not been identified. Using pGlu-Glu-Pro-NH2 ([Glu2]TRH) as a lead peptide and with modification at its central residue, our studies focused on some of its analogues synthesized as potential functional antagonists of TRH in the rodent brain. Among the peptides studied, the novel isomeric analogue [β-Glu2]TRH was found to suppress the analeptic and antidepressant-like pharmacological activities of TRH without eliciting intrinsic effects in these paradigms. [β-Glu2]TRH also completely reversed TRH’s stimulation of acetylcholine turnover in the rat hippocampus without a cholinergic activity of its own, which was demonstrated through in vivo microdialysis experiments. Altogether, [β-Glu2]TRH emerged as the first selective functional antagonist of TRH’s prominent cholinergic actions, by which this endogenous peptide elicits a vast array of central effects. 相似文献
540.
Laszlo Prokai Fatima Rahlouni Khadiza Zaman Vien Nguyen Katalin Prokai-Tatrai 《International journal of molecular sciences》2021,22(4)
The widely used rat uterotrophic assay to assess known and potential estrogenic compounds only considers uterine weight gain as endpoint measurement. To complement this method with an advanced technology that reveals molecular targets, we analyzed changes in protein expression using label-free quantitative proteomics by nanoflow liquid chromatography coupled with high-resolution mass spectrometry and tandem mass spectrometry from uterine protein extracts of ovariectomized rats after daily 17β-estradiol exposure for five days in comparison with those of vehicle-treated control animals. Our discovery-driven study revealed 165 uterine proteins significantly regulated by estrogen treatment and mapped by pathway analyses. Estrogen-regulated proteins represented cell death, survival and development, cellular growth and proliferation, and protein synthesis as top molecular and cellular functions, and a network found with the presence of nuclear estrogen receptor(s) as a prominent molecular node confirmed the relevance of our findings to hormone-associated events. An exploratory application of targeted proteomics to bisphenol A as a well-known example of an estrogenic endocrine disruptor is also presented. Overall, the results of this study have demonstrated the power of combining untargeted and targeted quantitative proteomic strategies to identify and verify candidate molecular markers for the evaluation of endocrine-disrupting chemicals to complement a conventional bioassay. 相似文献