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排序方式: 共有714条查询结果,搜索用时 15 毫秒
91.
92.
At first new epoxy derivatives, namely glycidylimide compounds, have been prepared using benzyltrimethylammonium chloride as catalyst and epichlorohydrin in excess. Their chemical and physical properties were studied. Spectral data confirmed these new structures. Afterwards new epoxy resins have been synthesized by the reaction of diimides and their glycidyl derivatives in N,N-dimethylformamide. The physical characteristics of the obtained polymers and also their solubilities are reported. Their IR, 1H- and 13C-NMR spectra allowed to confirm the polymer structure. Thermal analysis of these compounds showed their good thermal properties. 相似文献
93.
94.
R Dal Negro P Dal Negro-Turco E Lorenzi R Serra A Minette 《Revue de l'Institut d'hygiène des mines》1979,34(3):134-140
RG 033 is a compound consisting of betametasone in resinic microcapsules which allow a slow and continuous dialysis of the active drug through the membrane in the digestive tract. The drug was studied with regard to its effects on the distribution of alveolar air and its gastric tolerance. In a preliminary study the drug release from the capsules in the pH-conditions of the digestive tract was studied by means of a physico-chemical model. Two groups of 15 patients with broncho-obstruction reversed by salbutamol, a potent beta 2-sympathomimetic, were included in the trial. One group received 1 mg and the other 2 mg of the drug. An alternate scheme was used for the treatments. The functional methods used to assess the ventilatory results were chosen according to the conclusions of a previous comprehensive study by one of the authors [7] [8]. The ventilatory results of both dosages were quite similar. This observation suggests that a maximum effect on alveolar air distribution was obtained with 1 mg. No unfavourable side-effect on the gastric mucosa was observed. 相似文献
95.
MA Marchisio M Dubini G Serra T Mennini L Manara 《Canadian Metallurgical Quarterly》1976,33(4):269-271
The lipid-lowering effects of 3 g of the nicotinic acid derivative pentaerythritoltetranicotinate (niceritrol) given either 1 g X 3 or 1.5 g X 2 have been evaluated in 18 subjects with hyperlipoproteinaemia. When 1 g niceritrol was given three times daily, the serum TG concentration fell from 3.14 +/- 0.48 to 1.86 +/- 0.18 mmol/1 (41% reduction) and the serum cholesterol concentration from 282 +/- 9 to 227 +/- 11 mg/100 ml (20% reduction). The same daily dose, given 1.5 g twice, did not significantly lower the serum TG concentration, and serum cholesterol was lowered by only 12%. Niceritrol tablets prepared with a dissolution time of 60 or 90 min had identical lipid-lowering properties. Although patients may find it practical to take niceritrol only twice daily, such a dose regimen has considerably less effect on elevated serum lipids than a thrice-daily regimen. 相似文献
96.
The conduction mechanism in amorphous boron films sandwiched between plane gold electrodes has been investigated. The films, in the thickness range 3000–8000 Å, were obtained by the vacuum evaporation technique. The conduction process was examined in the temperature range 260–403 K with applied electric fields ranging from 103 to 105 V cm-1. The temperature and field dependences of the current flowing through the insulator are understandable in terms of the thermal emission of charge carriers over the Schottky barrier of a blocking contact. The theory of this type of electrode-limited conduction, derived by Simmons, predicts a current-voltage relationship of the type . A good fit of the experimental J-V curves to this relationship is obtained. Furthermore, a set of parameters has been calculated: the height and the transmission coefficient of the potential barrier are respectively 0.43 eV and 10-13, and the donor density within the insulator is equal to about 1021 cm-3. 相似文献
97.
In 102 insulin-dependent diabetic patients without retinopathy and with visual acuity 20/20, the Farnsworth-Munsell 100-Hue test was performed, and glycosylated hemoglobin (GlHb) levels were determined. In 70% of the patients, a dyschromatopsia in the yellow-blue axis (tritanopia) was found. No correlation existed between duration of diabetes and tritanopia. On the other hand, the degree of this visual defect was positively correlated with GlHb levels. Thus, dyschromatopsia might be associated with poor metabolic control. It is suggested that dyschromatopsia is a consequence of hypoxia at the neuroepithelial level. The high levels of GlHb could be a contributory cause of hypoxia by reduction of both oxygen release capacity and erythrocyte deformability. 相似文献
98.
A familial reciprocal translocation, established by R-banding as t(9;13) (9p23;13q21), is described in a phenotypically normal male carrier, whose father is also a balanced carrier and wife had four consecutive spontaneous abortions. The role of translocation in reproductive failure through production of chromosomally unbalanced gametes or by impairment of the spermatogenesis is briefly discussed. 相似文献
99.
A Dolei C Serra MV Arca F Tilocca M Pietravalle L Alemanno A Toniolo F Ameglio 《Canadian Metallurgical Quarterly》1994,134(1-2):157-168
Intracerebroventricular (i.c.v.) infusions of angiotensin II (AII) reliably induced c-fos expression in the supraoptic (SON) and paraventricular (PVN) nuclei, as well as other areas of the basal forebrain including the OVLT, subfornical organ (SFO), and bed nucleus (BNST). Double-labelling showed that AII-induced c-fos was observed in both vasopressin (AVP-) and oxytocin (OXY)-containing neurons of the SON and PVN in male rats. Allowing rats to drink water after AII infusions suppressed c-fos expression both AVP- and OXY-stained magnocellular neurons. Intragastric infusions of water were also effective, showing that oro-pharyngeal stimuli were not critical. Maximal suppression occurred in rats in whom water had been infused intragastrically about 5 min before i.c.v. AII infusions, suggesting that changes in osmolarity were responsible. i.c.v. AII also induced c-fos expression in a number of brainstem structures, including the solitary nucleus (NTS), lateral parabrachial nucleus (LPBN), locus coeruleus (LC), and the area postrema (AP). These results indicate that AVP and OXY-containing neurons in the magnocellular parts of the SON and PVN alter their immediate-early gene response to AII after water intake, and that this does not depend upon oro-pharyngeal factors. Furthermore, AII can induce c-fos expression in a number of brainstem nuclei associated with autonomic function, and these do not respond to water intake. 相似文献
100.
Chemical composition, nutritional value and other physico-chemical parameters of sea bass from two different geographical areas (Greece and Spain) and from aquaculture and wild origin were studied. Farmed and wild fish differ in proximate composition, colour, and especially in texture, fatty acids and free amino acids (FAAs) profiles. Flesh of wild fish was firmer, which could be attributed to their lower fat content and higher level of activity. Cultured fish showed a higher content of monounsaturated fatty acids and lower of saturated and polyunsaturated fatty acids (PUFAs). Within the PUFA group, n−3 fatty acids were predominant in wild sea bass, while n−6 were more abundant in farmed fish. Some FAAs related to the characteristic flavour of fish, such as glutamic acid, aspartic acid, alanine, and glycine were more abundant in cultured sea bass. No differences between fish from both farms were found, due to the similar composition of the feed used. 相似文献