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991.
992.
Daniel Swern H. B. Knight T. W. Findley 《Journal of the American Oil Chemists' Society》1944,21(5):133-139
Summary 1. Oleic acid, methyl oleate, and oleyl alcohol of high purity (93 to 96%) were prepared from readily available and inexpensive
commercial materials in 65 to 70% yields by fractional distillation and a single low-temperature fractional crystallization.
2. In the fractional distillation of red oil and its methyl esters, lower fractions amounting to about 20% of the starting
material were obtained. These are suggested for use in soap manufacture.
3. A fraction containing more than 50% linoleic acid was obtained from the C-18 fraction of red oil by fractional crystallization.
This fraction amounted to about 20% of the total starting material and had approximately the same percentage composition of
fatty acids as several important semi-drying oils.
This paper was presented at the meeting of the American Oil Chemists Society, held in Chicago, on October 7, 1943. 相似文献
993.
994.
Ashraf M. El-Sayed Lyn Cole John Revell Lee-Anne Manning Andrew Twidle Alan L. Knight Vincent G. M. Bus David M. Suckling 《Journal of chemical ecology》2013,39(5):643-652
Codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae), is a major cosmopolitan pest of apple and other pome fruits. Ethyl (E,Z)-2,4-decadienoate (pear ester) has been identified as a host-derived kairomone for female and male codling moths. However, pear ester has not performed similarly in different fruit production areas in terms of the relative magnitude of moth catch, especially the proportion of females caught. Our work was undertaken to identify host volatiles from apples, and to investigate whether these volatiles can be used to enhance the efficacy of host kairomone pear ester for monitoring female and male codling moths. Volatiles from immature apple trees were collected in the field using dynamic headspace sampling during the active period of codling moth flight. Using gas chromatography-electroantennogram detector (GC/EAD) analysis, six compounds elicited responses from antennae of females. These compounds were identified by GC/mass spectrometry (MS) and comparisons to authentic standards as nonanal, (E)-4,8-dimethyl-1,3,7-nonatriene, methyl salicylate, decanal, (Z,E)-α-farnesene, and (E,E)-α-farnesene. When the EAD-active compounds were tested individually in the field, no codling moths were caught except for a single male with decanal. However, addition of (E)-4,8-dimethyl-1,3,7-nonatriene, methyl salicylate, decanal, or (E,E)-α-farnesene to pear ester in a binary mixture enhanced the efficacy of pear ester for attracting female codling moths compared to pear ester alone. Addition of the 6-component blend to the pear ester resulted in a significant increase in the number of males attracted, and enhanced the females captured compared to pear ester alone; the number of males and females caught was similar to that with the pear ester plus acetic acid combination lure. Our results demonstrate that it is possible to synergize the response of codling moth to host kairomone by using other host volatiles. The new apple–pear ester host kairomone blend should be helpful for monitoring female codling moth, and may provide the basis for further improvement of codling moth kairomone. 相似文献
995.
Dangerfield EM Cheng JM Knight DA Weinkove R Dunbar PR Hermans IF Timmer MS Stocker BL 《Chembiochem : a European journal of chemical biology》2012,13(9):1349-1356
The immunomodulatory glycolipid α-galactosylceramide (α-GalCer) binds to CD1d and exhibits potent activity as a ligand for invariant CD1d-restricted natural killer-like T cells (iNKT cells). Structural analogues of α-GalCer have been synthesised to determine which components are required for CD1d presentation and iNKT cell activation, however, to date the importance of the phytosphingosine 4-hydroxyl for iNKT cell activation has been disputed. To clarify this, we synthesised two 4-deoxy α-GalCer analogues (sphinganine and sphingosine) and investigated their ability to activate murine and human iNKT cells. Analysis revealed that the analogues possessed comparable activity to α-GalCer in stimulating murine iNKT cells, but were severely compromised in their ability to stimulate human iNKT cells. Here we determined that species-specific glycolipid activity was due to a lack of recognition of the analogues by the T-cell receptors on human iNKT cells rather than insufficient presentation of the analogues on human CD1d molecules. From these results we suggest that glycolipids developed for potent iNKT cell activity in humans should contain a phytosphingosine base. 相似文献
996.
Walter Vetter Sophia Laure Christine Wendlinger Axel Mattes Andrew W. T. Smith David W. Knight 《Journal of the American Oil Chemists' Society》2012,89(8):1501-1508
Furan fatty acids (F-acids) are valuable bioactive compounds found at low concentrations in food. A method for the quantitative determination of saturated F-acids in food is reported. The sample preparation is based on accelerated solvent extraction, transesterification into methyl esters and silver ion chromatography (20% AgNO3 in silica, 1% deactivated) of the resulting methyl esters. There then follows determination of the enriched F-acid methyl (or ethyl) esters by GC/EI-MS in the selected ion monitoring (SIM) mode. The 9-(3-methyl-5-pentylfuran-2-yl)-nonanoic acid ethyl ester (9M5-EE) was used as an internal standard for recovery checks. The limit of detection was 11 pg, and the recovery rate of the silver ion chromatography was 85% (n = 5). Further F-acid standards were used for evaluation of individual SIM-responses. Application of the method to various biological samples gave the following results: champignons (n = 2) contained 1.7 or 2.5 mg/100 g dry weight F-acids, while fish oil capsules (n = 5) contained between 18 and 234 mg/100 g oil F-acids distributed over up to seven F-acids. The concentrations and patterns were different to fresh fish. Accordingly, fish oil supplements seem to be a minor source for F-acids compared to (fresh) fish. Organic butter samples (n = 4) contained about twice the amount of F-acids when compared with conventional butter (n = 5). 相似文献
997.
In Florida, the eastern North American population of the monarch butterfly exhibits geographic variability in population structure and dynamics. This includes the occurrence of migrants throughout the peninsula during the autumnal migration, occasional overwintering clusters that form along the Gulf Coast, remigrants from Mexico that breed in north-central Florida during the spring, and what have been assumed to be year-round, resident breeding populations in southern Florida. The work reported here focused on two monarch populations west of Miami and addressed four questions: Are there permanent resident populations of monarchs in southern Florida? Do these breed continuously throughout the year? Do they receive northern monarchs moving south during the autumn migration? Do they receive overwintered monarchs returning via Cuba or the Yucatan during the spring remigration from the Mexican overwintering area? Monthly collections and counts of spermatophores in the bursa copulatrices of females established that a resident population of continuously breeding monarchs exists year-round in southern Florida. It was determined through cardenolide fingerprinting that most of the butterflies had bred on the local southern Florida milkweed species, Asclepias curassavica. During the autumn migration period, however, some monarchs had fed on the northern milkweed, Asclepias syriaca. It appears that instead of migrating to Mexico, these individuals travel south through peninsular Florida, break diapause, mate with and become incorporated into the resident breeding populations. None of the monarchs captured in spring had the A. syriaca cardenolide fingerprint, which is evidence against the southern Florida populations receiving overwintered remigrants from Cuba, Central America or Mexico. 相似文献
998.
This communication describes a typical application of BCPL coroutines in simplifying the implementation of a multi-event task, together with some problems encountered. The problems fall into two major groups: those associated with the routing of operating system messages to coroutines within a task, and those connected with data shared between coroutines. General solutions are suggested to these problems, which can occur in any program employing similar structures. 相似文献
999.
The recognition potential (RP) was distinguished from P3 and eye blink responses by its sensitivity to visual area stimulated. Images were flashed in upper and lower hemifields. Current source density profiles were computed, using 16 midline scalp electrodes. For P3 and eye blink profiles, the hemifield stimulated was not a significant factor. For the recognition potential, upper and lower field stimulation produced radically different profiles. An improved recognition potential signal was obtained by a new mathematical procedure. It used the difference in sensitivity to visual area stimulated to reject P3 and eye blink responses. 相似文献
1000.
T Knight Z Smith JA Lockton P Sahota A Bedford M Toop E Kernohan MR Baker 《Canadian Metallurgical Quarterly》1993,47(2):89-95
OBJECTIVES: To assess and compare the prevalence of established risk markers for ischaemic heart disease in a sample of Asian and non-Asian men and to relate these observations to preventive strategies. SETTING: Two factories in the textile industry in Bradford, West Yorkshire, UK. Subjects--288 male manual workers aged 20 to 65 years. DESIGN: Cross sectional study within one occupational/social class stratum. MEASUREMENTS AND MAIN RESULTS: Age, body mass index, plasma lipids, fibrinogen and serum insulin values, blood pressure, smoking habits, alcohol consumption, and exercise routines were recorded. Plasma total cholesterol concentrations were significantly lower in Asian than non-Asian men (5.3 mmol/l v 5.8 mmol/l respectively, p < 0.0001), as were low density lipoprotein cholesterol concentrations (3.4 mmol/l v 3.7 mmol/l, p = 0.0150), and high density lipoprotein (HDL) cholesterol (1.1 mmol/l v 1.3 mmol/l, p < 0.0001). Hypercholesterolaemia (concentration > 6.5mM) was present in nearly one quarter of non-Asians but less than one eighth of Asian men. Triglyceride values were not significantly higher in Asians. Smoking rates were high in non-Asians (43.8%) and only slightly lower in Asians (39.1%). Asian smokers smoked fewer cigarettes per day on average (9.3 v 16.1, p = 0.0001). Almost a quarter of non-Asian men (23.1%) and 26.6% of Asian men had raised blood pressure. Systolic pressures were higher in non-Asian men (138.3 mmHg v 133.0 mmHg, p = 0.0070), but diastolic pressures showed no ethnic differences. Diabetes was more prevalent in Asian men (10.9% v 4.4% p < 0.05), who also showed higher serum insulin concentrations after glucose loading (22.3 mU/l v 10.2 mU/l, p < 0.0001). Plasma fibrinogen values were higher in non-Asian men (2.9 g/l v 2.6 g/l, p < 0.0001) and these were associated with smoking. Nearly all non-Asians (92.5%) consumed alcohol at some time whereas 62.5% of Asians habitually abstained from alcohol consumption. Among the drinkers, non-Asian men consumed on average, 23.9 units per week and Asian men 18.4 units per week (p = 0.083). The mean body mass index for Asian men was 24.5 kg/m2 which was not significantly different to the mean in non-Asian men (25.2 kg/m2). The frequency of exercise in leisure time was low in both groups with 44.4% of non-Asian and 21.1% of Asian men taking moderate exercise weekly, and even fewer, regular strenuous exercise (16.3% and 8.6% respectively). CONCLUSIONS: The plasma cholesterol and fibrinogen concentrations, prevalence of hypertension, smoking habits, alcohol intakes, and infrequency of exercise in leisure time in these non-Asian men in Bradford were consistent with an increased risk of heart disease. The pattern of risk markers was clearly different in Asian men. Only their lower HDL cholesterol concentrations, marginally higher triglyceride values, higher prevalence of diabetes, and very low frequency of exercise in leisure time would be consistent with a higher risk of heart disease compared with non-Asians. The implications of these observations for heart disease preventive strategies are discussed. 相似文献