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91.
A new dioxomolybdenum(VI) complex with a chiral tetradentate ligand is reported. The tripodal ligand containing two nitrogen atoms and two phenolic oxygen atoms was synthesized starting from a chiral diamine precursor. Further reaction with [MoO2(acac)2] yielded a monomeric molybdenum complex as a bright yellow solid. The structures of the molybdenum complex and the free diamine bis-phenol ligand were determined by X-ray diffraction.  相似文献   
92.
The quest for novel natural-like biomolecular probes that can be used to gain information on biological recognition events is of topical interest to several scientific areas. In particular, the recognition of carbohydrates by proteins modulates a number of important biological processes. These molecular recognition events are, however, difficult to study by the use of naturally occurring oligosaccharides and polysaccharides owing to their intrinsic structural heterogeneity and to the many technical difficulties encountered during the isolation of sufficient quantities of pure material for detailed structural and biological studies. Therefore, the construction of homogenous biomolecular probes that can mimic both the biophysical properties of polysaccharide backbones and the properties of bioactive oligosaccharide fragments are highly sought after. Herein, synthetic methodology for the construction of well-defined bioconjugates consisting of biologically relevant disaccharide fragments grafted onto a dextran backbone is presented, and a preliminary NMR spectroscopy study of their interactions with galectin-3 as a model lectin is conducted.  相似文献   
93.
OBJECTIVES: The occurrence and causes of hairdressers' occupational skin and respiratory diseases were studied. METHODS: Of a random sample of 500 female hairdressers aged 15-54 years, 355 were available for study. Of the 189 reporting work-related skin and respiratory symptoms in a computer-aided telephone interview on exposure and health, 130 underwent a physical examination, lung function tests, prick and patch testing, and nasal and lung provocation tests. An occupational disease was diagnosed when the causality between exposure and disease was probable and the clinical tests supported the diagnosis. RESULTS: The telephone interview revealed a life-time prevalence of 16.9% for hand dermatoses, 16.9% for allergic rhinitis, and 4.5% for asthma among the hairdressers. In the clinical investigations, the prevalence was 2.8% for occupational dermatoses, 1.7% for occupational rhinitis, and 0.8% for occupational asthma. Ammonium persulfate caused 90% of the respiratory diseases and 27% of the hand dermatoses. Paraphenylenediamine, natural rubber latex, and skin irritation were also causes of hand dermatitis. Allergy to human dandruff (8.6%) and Pityrosporum ovale (12.1%) was common. Previously diagnosed atopic diseases increased the risk for occupational skin or respiratory disease 3-fold (odds ratio 2.9, 95% confidence interval 1.1-7.9). Of the cases, 37.5% (6 of 16 persons) had to change occupations during a 3-year follow-up. CONCLUSIONS: Work-related skin and respiratory symptoms are common among hairdressers. Often a specific cause (eg, ammonium persulfate) can be found if occupational diseases are suspected and diagnosed. Hairdressers with atopic diseases are at risk of developing occupational skin and respiratory diseases.  相似文献   
94.
WCDMA and WLAN for 3G and beyond   总被引:9,自引:0,他引:9  
The WCDMA air interface was initially designed to support a wide variety of services with different QoS requirements having a maximum bit rate of 2 Mb/s. In order to satisfy the future service and application needs several technical enhancements are being studied and standardized for WCDMA in 3GPP. Even with evolved WCDMA, there is a need for another public wireless access solution to cover the demand for data-intensive applications and enable smooth online access to corporate data services in hot spots. This need could be fulfilled by WLAN together with a high-data-rate cellular WCDMA system. WLAN offers an interesting possibility for cellular operators to offer additional capacity and higher bandwidths for end users without sacrificing the capacity of cellular users. The evolved WCDMA air interface will provide better performance and higher bit rates than basic WCDMA, based on first releases of the specifications. Eventually, evolution may not be the answer to all the needs, and come revolutionary concepts need to be considered. However, before some future wireless system can be regarded as belonging to 4G it must possess capabilities that by far exceed those of 3G systems like WCDMA. Judging from an application and services point of view, one distinguishing factor between 3G and 4G will still be the data rate. We could define that 4G should support at least 100 Mb/s peak data rates in full-mobility wide area coverage and 1 Gb/s in low-mobility local area coverage. Other possible characteristics of 4G need to be further studied.  相似文献   
95.
Acid-catalyzed isomerization of fucosterol and Δ5-avenasterol   总被引:1,自引:0,他引:1  
This work shows that fucosterol, Δ5-avenasterol, and similar ethylidene-side chain sterols can undergo acid-catalyzed isomerization to give a mixture of five isomers. Four isomers formed from fucosterol were analyzed, using gas chromatography-mass spectrometry, and were characterized as Δ5-avenasterol two Δ5,23-stigmastadienols, and Δ5,24(250)-stigmastadienol. When the unsaponifiables fraction from oat oil was subjected to acid hydrolysis, the two Δ5,23-stigmastadienol isomers and Δ5,24(25)-stigmastadienol were detected while fucosterol coeluted with sitosterol. Interisomerization of ethylidene-side chain sterols represents a limitation to the use of the acid hydrolysis method in the determination of sterols in food and other plant materials rich in these sterols, e.g., oat lipids.  相似文献   
96.
Antioxidant properties of 5 to 500 μg/g levels of α-and γ-tocopherols, in the oxidation of rapeseed oil triacylglycerols (RO TAG), were studied at 40°C in the dark. Each tocopherol alone and in a mixture was studied for its stability in oxidizing RO TAG. Also the effects of tocopherols on the formation of primary and secondary oxidation products of RO TAG were investigated. Both tocopherols significantly retarded the oxidation of RO TAG. At low levels (≤50 μg/g), α-tocopherol was more stable and was a more effective antioxidant than γ-tocopherol. At higher α-tocopherol levels (>100 μg/g), there was a relative increase in hydroperoxide formation parallel to consumption of α-tocopherol, which was not found with γ-tocopherol. Therefore, γ-tocopherol was a more effective antioxidant than α-tocopherol at levels above 100 μg/g. As long as there were tocopherols present, the hydroperoxides were quite stable and no volatile aldehydes were formed. In a mixture, α-tocopherol protected γ-tocopherol from being oxidized at the addition levels of 5+5 and 10+10 μg/g but no synergism between the tocopherols was found. α-Tocopherol was less stable in the 500+500 μg/g mixture than when added alone to the RO TAG. No prooxidant activity of either tocopherol or their mixture was found.  相似文献   
97.
The effects of minor amounts of γ-tocopherol on the oxidation of natural triacylglycerols (TAG) of rapeseed (RO) and butter oils (BO) were studied. Four different TAG materials were blended from chromatographically purified TAG that contained 100–25% of RO TAG. The RO TAG contained from <1 to 43 μg γ-tocopherol per gram of TAG, which corresponded to ≤6% of the total tocopherols in the original RO. The TAG were held at 40°C in the dark for 4 wk and followed at regular intervals by measurements of hydroperoxide formation by peroxide values and of secondary product formation by p-anisidine values at regular intervals. In all TAG, minor amounts of γ-tocopherol retarded oxidation. In RO TAG, concentrations as low as 11 μg/g of γ-tocopherol (1.5% of the total tocopherols in the original RO) were enough to decrease hydroperoxide and secondary product formation to 46 and 39%, respectively. The effect was even more important in TAG mixtures that contained BO TAG. There were no significant differences between oxidation of the RO TAG at 24 μg/g, the 75% RO TAG mixture at 11 μg/g, and the 50% RO TAG mixture at 3 μg/g of γ-tocopherol. Even at these minor levels, γ-tocopherol was a significant antioxidant, which is important in oxidation studies of purified model systems.  相似文献   
98.
Lampi AM  Moreau RA  Piironen V  Hicks KB 《Lipids》2004,39(8):783-787
Because of the positive health effects of phytosterols, phytosterol-enriched foods and foods containing elevated levels of natural phytosterols are being developed. Phytosterol contents in cereals are moderate, whereas their levels in the outer layers of the kernels are higher. The phytosterols in cereals are currently underutilized; thus, there is a need to create or identify processing fractions that are enriched in phytosterols. In this study, pearling of hulless barley and rye was investigated as a potential process to make fractions with higher levels of phytosterols. The grains were pearled with a laboratory-scale pearler to produce pearling fines and pearled grains. Lipids were extracted by accelerated solvent extraction, and nonpolar lipids were analyzed by normal-phase HPLC with ELSD and UV detection. Total sterol analyses were performed by GC. After a 90-s pearling, the amounts of pearling fines from hulless barley and rye were 14.6 and 20.1%, respectively, of the original kernel weights. During pearling, higher levels of phytosterols and other lipids were fractionated into the fines. The contents of free sterols and sterols esterified with FA in the fines were at least double those in the whole grains. Pearling fines of hulless barley and rye contained >2mg/g phytosterol compounds, which makes them a good source of phytosterols and thus valuable raw materials for health-promoting foods.  相似文献   
99.
Vascular adhesion protein-1 (VAP-1) is a dimeric 170-kDa endothelial transmembrane molecule that under normal conditions is most strongly expressed on the high endothelial venules of peripheral lymph nodes and on hepatic endothelia. It is a glycoprotein that mediates tissue-selective lymphocyte adhesion in a sialic acid-dependent manner. In this study, we report the detection of a soluble form of VAP-1 in circulation. We developed a quantitative sandwich ELISA using novel anti-VAP-1 mAbs and used it to determine the levels of soluble VAP-1 (sVAP-1) in the serum of healthy individuals and in patients with inflammatory diseases. In healthy persons, circulating sVAP-1 concentrations were 49 to 138 ng/ml. Immunoblotting studies revealed that the apparent molecular mass of dimeric sVAP-1 is slightly (approximately 10 kDa) higher than that of transmembrane VAP-1 under nonreducing conditions. In contrast, the electrophoretic mobilities of monomeric sVAP-1 and transmembrane VAP-1 were similar after reduction and boiling. Adhesion assays showed that the circulating sVAP-1 modulates lymphocyte binding to endothelial cells. Inflammation can cause an elevation of serum sVAP-1 levels, because sVAP-1 concentrations in patients with certain liver diseases were two- to fourfold higher than those in normal individuals. In contrast, rheumatoid arthritis and inflammatory bowel diseases were not associated with elevated levels of sVAP-1. These findings indicate that there is a functionally active, soluble form of VAP-1 in circulation and suggest that the serum level of sVAP-1 might be a useful marker of disease activity in inflammatory liver diseases.  相似文献   
100.
AIMS: We examined the relationship between apoptosis and three different major stages of human breast carcinoma: intraductal carcinoma (DCIS), infiltrating duct carcinoma (IDC) and metastatic carcinoma in lymph nodes. We also determined the correlation between apoptosis and oestrogen receptor (ER), progesterone receptor (PR) and p53. METHODS AND RESULTS: The study investigates the extent of apoptosis in 63 breast carcinomas by in-situ end-labelling, in formalin-fixed, paraffin-processed tissue sections. The 63 breast carcinomas, included 22 DCISs, 26 IDCs, three infiltrating lobular carcinomas (ILC) and 12 metastatic lymph nodes. The apoptotic labelling index was higher in DCIS than IDC and metastatic carcinoma (P < 0.001, P < 0.007, respectively). By immunohistochemistry, we also analysed p53, ER and PR. Apoptosis correlated significantly with p53 (r = 0.748, P = 0.0004) in IDC. Also, ER correlated significantly with PR (r = 0.629, P = 0.00001). No apparent correlation was found between the apoptosis and ER or PR. CONCLUSION: Our data suggest that not only does apoptosis differ between intraductal carcinoma and infiltrating carcinoma but also it might be regulated by altered p53 expression.  相似文献   
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