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991.
Kirsten M. Herbach Christine Maier Florian C. Stintzing Reinhold Carle 《European Food Research and Technology》2007,224(5):649-658
Purple pitaya (Hylocereus polyrhizus) fruits have been recently proposed as a promising source of betalains. In the present study, purple pitaya juice processing
at pilot-plant scale is reported for the first time. Each processing step was examined in terms of juice colour and betacyanin
retention. Lightness (L
*) and hue angle (h°) values were strongly influenced by juice filtration, while chroma (C
*) and betacyanin retention were most strongly altered by pasteurisation. Three systems of juice pasteurisation were evaluated.
Betacyanin loss and colour alteration were minimal upon pasteurisation in an HTST system and a standard tubular heat exchanger,
respectively. Additionally, storage experiments using mucilage-free purple pitaya juice were conducted. Whereas light exposure
of unsupplemented samples resulted in significant pigment degradation, detrimental effects of light exposition were completely
prevented by the addition of 1% ascorbic acid prior to storage. After 6 months, about 70% of the initial betacyanin content
was retained in the presence of ascorbic acid, irrespective of illumination. 相似文献
992.
Nilsson J Pillai D Onning G Persson C Nilsson A Akesson B 《Molecular nutrition & food research》2005,49(3):239-246
A comparison was made on the use of two spectrophotometric methods, the ferric reducing antioxidant power (FRAP) method and the 2,2'-azinobis-3-ethylbenzotiazoline-6-sulfonic acid (ABTS) method, for the measurement of the total antioxidant capacity (TAC) of plant foods. The correlations of TAC measured by the two methods were highly significant in both water-soluble (r2= 0.90) and water-insoluble extracts (r2= 0.98) from 13 strawberry samples. Also a corresponding comparison of TAC in extracts from 14 plant species showed high correlation coefficients, r2= 0.98 for water-soluble extracts and r2= 0.88 for water-insoluble extracts. The ratio of TAC values obtained with the two methods (ABTS/FRAP) varied between 0.7 and 3.3 for different plant extracts indicating that they contained antioxidants with varying reactivity in the two methods. TACs in six pure antioxidant substances were ranked in the following order by both methods: quercetin > ferulic acid > catechin > rutin > caffeic acid > Trolox = chlorogenic acid. The two methods showed similar TAC values for quercetin, rutin, caffeic acid and chlorogenic acid while ferulic acid and catechin gave higher results with the ABTS method than with the FRAP method, and such differences probably explain the varying ratios of ABTS/FRAP obtained in foods. Regarding storage TAC in water-soluble strawberry extracts stored at -20 or -80 degrees C was stable for at least five months while storage at 4 degrees C decreased the TAC value with 40% during five weeks of storage. The study showed that both the ABTS and FRAP methods can be used for convenient monitoring of the antioxidant capacities in fruit and vegetables, and that different antioxidants had varying reactivity in the two methods. 相似文献
993.
994.
Claudia Paoletti Andreas Heissenberger Marco Mazzara Sara Larcher Emanuele Grazioli Philippe Corbisier Norbert Hess Gilbert Berben Peter S. Lübeck Marc De Loose Gillian Moran Christine Henry Carlo Brera Imma Folch Jaroslava Ovesna Guy Van den Eede 《European Food Research and Technology》2006,224(1):129-139
The reliability of analytical testing is strongly affected by sampling uncertainty. Sampling is always a source of error and the aim of “good” sampling practice is to minimize this error. Generally the distribution of genetically modified (GM) material within lots is assumed to be random in order to use binomial distribution to make inferences. This assumption was never verified in practice and no experimental data investigating the distribution of genetically modified organisms (GMOs) exist. The objectives of the KeLDA project were: (1) to assess the distribution of GM material in soybean lots (2) to estimate the amount of variability of distribution patterns among lots. The GM content of 15 soybean lots imported into the EU was estimated (using real-time PCR methodology) analyzing 100 increment samples systematically sampled from each lot at predetermined time intervals during the whole period of off-loading. The distribution of GM material was inferred by the one-dimensional (temporal) distribution of contaminated increments. All the lots display significant spatial structuring, indicating that randomness cannot be assumed a priori. The evidence that the distribution of GM material is heterogeneous highlights the need to develop sampling protocols based on statistical models free of distribution requirements. 相似文献
995.
Johnson AL Ratajczak C Haugen MJ Liu HK Woods DC 《Reproduction (Cambridge, England)》2007,133(3):609-616
Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) represents one of several cytokine members of the tumor necrosis factor superfamily reported to initiate apoptosis in a wide range of transformed, but not most normal, cell types. The present studies were conducted to evaluate the potential for TRAIL to promote apoptotic cell death in differentiated granulosa cells collected from hen preovulatory follicles. While mRNA encoding critical components (including TRAIL) required for a functional extrinsic cell death pathway are expressed in granulosa cells, TRAIL treatment by itself fails to induce either caspase-3 activity or a decrease in cell viability. On the other hand, preculture of cells with the conventional chemotherapeutic, cisplatin, or the 20S proteosome inhibitor, Z-LLF-CHO, sensitizes granulosa cells to TRAIL as evidenced by enhanced caspase-3 activity after 4 h of culture and loss of cell viability after 24 h when compared with either cisplatin or Z-LLF-CHO treatment alone. Moreover, the sensitizing effect of Z-LLF-CHO on TRAIL-induced loss of cell viability is prevented by the selective caspase-8 inhibitor, Z-IETD-FMK. Interestingly, TRAIL mRNA expression is elevated both in prehierarchal follicles undergoing spontaneous atresia and in prehierarchal follicles induced to undergo atresia for 6 h in vitro. In summary, the data demonstrate the presence of a functional TRAIL signaling pathway in hen granulosa cells, and are consistent with the possibility that TRAIL signaling may directly or indirectly participate in the process of follicle atresia in vivo. 相似文献
996.
Paul J Moughan Alison J Darragh William C Smith Christine A Butts 《Journal of the science of food and agriculture》1990,52(1):13-21
The efficacy of perchloric and trichloroacetic acids as precipitants of protein from endogenous digesta collected from the distal ileum of the laboratory rat was evaluated. Twelve 190-g male rats were fed a protein-free diet and samples of ileal digesta were collected after slaughter. The digesta were pooled, and subsamples were treated with PCA or TCA or were left untreated. For both precipitants more than half of the total nitrogen (N) remained in solution post-precipitation, and for the PCA and TCA treatments respectively at least 35 and 69% of the supernatant N was in the form of soluble protein. The amino acids (after acid hydrolysis) having the highest concentrations in the supernate are known to be abundant in the mucoproteins. Around 6.4 and 9.8% of the supernatant N was in the form of non-amino N (creatinine N + urea N + ammonia N) for the PCA and TCA treatments respectively. 相似文献
997.
Christine Ton Nu Patrick MacLeod Jacques Barthelemy 《Food quality and preference》1996,7(3-4):251-262
This study explored food habits and preferences of 222 French adolescents of 10 to 20 years old. They completed a questionnaire about their eating habits and quoted 10 of their favourite and 10 of their most disliked foods or beverages. They also mentioned any change in their preferences.
These results show that food habits and tastes are mostly related to age and gender. Girls pay more attention to dietetics and snack less than boys. Young adolescents prefer bland and familiar foods whereas older ones learn to appreciate ‘adult’ foods. As they grow older, children snack more, skip more meals and seem more interested in foreign foods. Before puberty teenagers reject many foods they previously liked. After puberty they begin to appreciate some foods they didn't like before. Their food repertoire widens at this period because of social and cognitive influences. 相似文献
998.
999.
Purpose
To investigate effect of topical anaesthetic (TA) during gas permeable (GP) contact lens (CL) fitting on subjective and objective measures of patient anxiety.Methods
47 subjects (mean ± sd age = 26.9 ± 4.9 years; soft CL wearers, 18, neophytes, 29). Each subject randomly assigned to Group A or B, and attended on two occasions, one week apart. First visit: subject received bilaterally either a single drop of TA (0.5% proxymetacaine) (Group A) or placebo (0.9% saline) (Group B) prior to GP CL application. No drops were instilled at second visit. Each visit mimicked a GP CL fitting. At each visit, patient anxiety was assessed either subjectively (visual analogue scale (VAS)) or objectively (skin conductance (SC)), as well as anterior ocular health.Results
Visit 1: GP CL trial produced small increases in hyperaemia and corneal staining, but no difference associated with TA use. Visit 2: increases in staining and hyperaemia were observed, but hyperaemic responses significantly less than at Visit 1, for both groups. Corneal staining also less, but not statistically significant. VAS scores indicated subjects who received TA during Visit 1 were significantly less anxious at Visit 2. Visit 2: comfort slightly reduced for subjects who received TA at Visit 1, and significantly increased for subjects who received placebo. Use of TA reduced anxiety during lens adaptation period compared with subjects receiving placebo.Conclusions
TA use during GP CL fitting has potential patient benefits: improved first-time GP CL wear comfort, reduced anxiety during adaptation, reduced anxiety prior to subsequent GP CL wear. 相似文献1000.
Food safety self-reported behaviors and cognitions of young adults: results of a national study 总被引:4,自引:0,他引:4
Byrd-Bredbenner C Maurer J Wheatley V Schaffner D Bruhn C Blalock L 《Journal of food protection》2007,70(8):1917-1926
With limited opportunities to learn safe food handling via observation, many young adults lack the knowledge needed to keep them safe from foodborne disease. It is important to reach young adults with food safety education because of their current and future roles as caregivers. With a nationwide online survey, the demographic characteristics, self-reported food handling and consumption behaviors, food safety beliefs, locus of control, self-efficacy, stage of change, and knowledge of young adults with education beyond high school (n = 4,343) were assessed. Young adults (mean age, 19.92 +/- 1.67 SD) who participated were mainly female, white, never married, and freshmen or sophomores. Participants correctly answered 60% of the knowledge questions and were most knowledgeable about groups at greatest risk for foodborne disease and least knowledgeable about common food sources of foodborne disease pathogens. They reported less than optimal levels of safe food handling practices. Young adults generally had a limited intake of foods that increase the risk of foodborne disease, positive food safety beliefs, an internal food safety locus of control, and confidence in their ability to handle food safely, and they were contemplating an improvement in, or preparing to improve, their food handling practices. Females significantly outperformed males on nearly all study measures. Future food safety educational efforts should focus on increasing knowledge and propelling young adults into the action stage of safe food handling, especially males. Efforts to improve knowledge and, ultimately, food safety behaviors are essential to safeguard the health of these young adults and enable them to fulfill the role of protecting the health of their future families. 相似文献