全文获取类型
收费全文 | 493篇 |
免费 | 20篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 134篇 |
金属工艺 | 3篇 |
机械仪表 | 1篇 |
建筑科学 | 19篇 |
矿业工程 | 1篇 |
能源动力 | 9篇 |
轻工业 | 87篇 |
水利工程 | 3篇 |
无线电 | 18篇 |
一般工业技术 | 61篇 |
冶金工业 | 111篇 |
原子能技术 | 1篇 |
自动化技术 | 63篇 |
出版年
2023年 | 2篇 |
2022年 | 11篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 12篇 |
2018年 | 12篇 |
2017年 | 10篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 14篇 |
2013年 | 31篇 |
2012年 | 24篇 |
2011年 | 35篇 |
2010年 | 21篇 |
2009年 | 19篇 |
2008年 | 21篇 |
2007年 | 38篇 |
2006年 | 14篇 |
2005年 | 17篇 |
2004年 | 16篇 |
2003年 | 17篇 |
2002年 | 17篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 12篇 |
1997年 | 4篇 |
1996年 | 16篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1982年 | 3篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 10篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有513条查询结果,搜索用时 15 毫秒
91.
Specular ellipsometry is a well-known and efficient technique to characterize surfaces and coatings. This technique has been extended to the measurement of scattered light. We present an experimental setup, using a polarization modulator, which permits us to characterize transition layers and roughness without a calibration procedure. Experimental results are presented concerning transition layers for damage threshold applications and for rough surfaces or bulks. 相似文献
92.
Dietary emulsifiers from milk and soybean differently impact adiposity and inflammation in association with modulation of colonic goblet cells in high‐fat fed mice 下载免费PDF全文
93.
Magar VS Johnson GW Brenner RC Quensen JF Foote EA Durell G Ickes JA Peven-McCarthy C 《Environmental science & technology》2005,39(10):3538-3547
Under anaerobic conditions, such as those typically found in buried sediments, the primary metabolic pathway for polychlorinated biphenyls (PCBs) is reductive dechlorination in which chlorine removal and substitution with hydrogen by bacteria result in a reduced organic compound with fewer chlorines. Vertical sediment cores were collected from Lake Hartwell (Pickens County, SC) and analyzed in 5-cm intervals for 107 PCB congeners in a total of more than 280 samples from 18 sediment cores and surface samples. This paper reports on extensive PCB dechlorination measured in Lake Hartwell sediments and the characterization of dechlorination end-member (EM) patterns using chemical forensic methods. PCB congener fingerprinting and a multivariate receptor modeling method, polytopic vector analysis (PVA), were used for identification and characterization of weathered and dechlorinated PCB congener patterns. Dechlorination resulted in a substantial shift in buried sediments from tetra- through decachlorobiphenyl congeners to mono- through trichlorobiphenyl congeners. Mono- through trichlorobiphenyls comprised approximately 80% of the PCBs in buried sediments that underwent maximum dechlorination as compared to approximately 20% in surface sediments. The major concentration decreases were seen in the tetra- through hexachlorobiphenyl homologues, which accounted for over 90% of the dechlorination. Octa- through decachlorobiphenyl congeners also were dechlorinated, but their overall contribution to dechlorination was relatively small due to their low initial concentrations (< 5%). The net accumulation of 2-CB, 2,2'/2,6-DCBs, 2,4'-DCB, 2,2',4-TCB, and 2,2',6-TCB at Lake Hartwell matched characteristic PCB dechlorination products reported in the literature, such as those for Processes M, Q, and C; and the persistence of tetrachlorobiphenyls (TeCBs) that contained 24- and 25-congener groups resembled dechlorination Processes H or H'. Although dechlorination tended to be very extensive in most of the cores, it was not always consistent from core to core or at various depth intervals within a single core. The reason for this variability in dechlorination extent could not be determined from the existing data and did not appear to correlate with such factors as PCB concentration, total organic carbon, or age. The authors used fingerprinting analysis and a PVA multivariate receptor model as exploratory data analysis tools to characterize PCB sources and their alteration patterns. Dominant sources and alteration patterns were determined in this large data set by comparing PVA EM patterns with known source patterns (i.e., Aroclors or Aroclor mixtures) and literature-reported alteration patterns. PVA also afforded an opportunity to characterize the vertical and lateral distributions of the weathered and unweathered PCB source patterns and dechlorination patterns, a task that would have been much more difficult to accomplish through comparison of chromatograms alone. 相似文献
94.
Ho D Fitzgerald M Bartlett CA Zdyrko B Luzinov IA Dunlop SA Swaminathan Iyer K 《Nanoscale》2011,3(3):907-910
RADA16 self-assembling peptide nanofiber scaffolds (SAPNSs) have been shown to have positive effects on neural regeneration following injury to the central nervous system in vivo, but mechanisms are unclear. Here we show that RADA16 SAPNSs form scaffolds of increasing fiber density with increasing peptide concentration which in turn has a concentration-dependent effect on neurons and astrocytes in mixed retinal cultures. Importantly, we report that the final nanoscale fiber architecture is an important factor to consider in designing scaffolds to promote regeneration in the central nervous system. 相似文献
95.
Carole M. Counihan 《Food and Foodways: Explorations in the History and Culture of》2013,21(4):357-375
Rudolph M. Bell (1985). Holy Anorexia. Epilogue by William N. Davis. Chicago: University of Chicago Press. Joan Jacobs Brumberg (1988). Fasting Girls: The Emergence of Anorexia Nervosa as a Modern Disease. Cambridge: Harvard University Press. Caroline Walker Bynum (1987). Holy Feast and Holy Fast: The Religious Significance of Food to Medieval Women. Berkeley: University of California Press. 相似文献
96.
Pierre Gélinas Carole McKinnon 《International Journal of Food Science & Technology》2013,48(9):1956-1961
The bread‐making potential of flour may be roughly estimated by dough rheology, especially its tolerance to over‐mixing as determined with the farinograph. The objective of this study was to identify the relative effects of experimental conditions likely to affect dough mixing stability: mixer speed, temperature, salt, yeast and bread additives such as ascorbic acid and preservatives. The addition of 1–2% salt or ascorbic acid (50 mg kg?1 flour) improved dough mixing stability and counteracted the negative effect of bread preservatives. Mixing salted dough at slow speed (63 rpm) and 25 °C might be a more realistic bread‐making procedure for performing dough rheology assays with equipment such as the farinograph, compared to official methods (only flour and water, no salt; 30 °C). Amongst five bread wheat cultivars, differences existed in dough strengthening response to both salt and ascorbic acid, a property that may find application in wheat breeding and screening. 相似文献
97.
98.
99.
Grégory Chatelain Micaël Ripert Carole Farre Salomé Ansanay-Alex Carole Chaix 《Electrochimica acta》2012
We report the use of a four-ferrocene modified oligonucleotide as a probe for DNA detection with a gold electrode microsystem. This oligonucleotide is synthesized by automated solid-phase synthesis with four successive ferrocene moieties at the 5′-end and a C6-thiol modifier group at the 3′-end. The grafting of this 4Fc-DNA probe on a gold electrode microsystem results in the appearance of the ferrocene redox couple in cyclic voltammetry. The probe sequence is a stem-loop structure that folds efficiently on the electrode, thus optimizing electron transfer. Such architecture serves as sensor for DNA detection which is based on hybridization. The resulting disposable voltammetric sensor allowed direct, reagentless DNA detection in a small volume (20 μL). Electrochemical response upon hybridization with complementary short sequence (30-base length) and long sequence (50-base length) strands was observed by differential pulse voltammetry. Current variations were compared. The longer the sequence, the greater the decrease in current. The system's detection limit was estimated at 3.5 pM (0.07 fmol in 20 μL) with the 50-base length target and provided a dynamic detection range between 3.5 pM and 5 nM. Single mismatch detection showed a good level of sensitivity. The system was regenerated twice with no significant loss of Fc signal. Finally, 1 pM sensitivity was reached with a long chain analog of DNA PCR products of Influenza virus. 相似文献
100.