全文获取类型
收费全文 | 640篇 |
免费 | 20篇 |
专业分类
电工技术 | 10篇 |
综合类 | 13篇 |
化学工业 | 145篇 |
金属工艺 | 5篇 |
机械仪表 | 12篇 |
建筑科学 | 30篇 |
能源动力 | 9篇 |
轻工业 | 90篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 43篇 |
一般工业技术 | 144篇 |
冶金工业 | 112篇 |
原子能技术 | 5篇 |
自动化技术 | 39篇 |
出版年
2023年 | 6篇 |
2022年 | 4篇 |
2021年 | 28篇 |
2020年 | 15篇 |
2019年 | 13篇 |
2018年 | 11篇 |
2017年 | 7篇 |
2016年 | 15篇 |
2015年 | 15篇 |
2014年 | 15篇 |
2013年 | 40篇 |
2012年 | 24篇 |
2011年 | 32篇 |
2010年 | 29篇 |
2009年 | 19篇 |
2008年 | 28篇 |
2007年 | 24篇 |
2006年 | 18篇 |
2005年 | 21篇 |
2004年 | 14篇 |
2003年 | 18篇 |
2002年 | 14篇 |
2001年 | 11篇 |
2000年 | 18篇 |
1999年 | 16篇 |
1998年 | 30篇 |
1997年 | 23篇 |
1996年 | 19篇 |
1995年 | 17篇 |
1994年 | 12篇 |
1993年 | 13篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1974年 | 3篇 |
1973年 | 2篇 |
排序方式: 共有660条查询结果,搜索用时 31 毫秒
1.
Klaus Reinhardt Hans Georg Breunig Aisada Uchugonova Karsten K?nig 《Journal of the Royal Society Interface》2015,12(110)
We explore the possibility of characterizing sperm cells without the need to stain them using spectral and fluorescence lifetime analyses after multi-photon excitation in an insect model. The autofluorescence emission spectrum of sperm of the common bedbug, Cimex lectularius, was consistent with the presence of flavins and NAD(P)H. The mean fluorescence lifetimes showed smaller variation in sperm extracted from the male (tau m, τm = 1.54–1.84 ns) than in that extracted from the female sperm storage organ (tau m, τm = 1.26–2.00 ns). The fluorescence lifetime histograms revealed four peaks. These peaks (0.18, 0.92, 2.50 and 3.80 ns) suggest the presence of NAD(P)H and flavins and show that sperm metabolism can be characterized using fluorescence lifetime imaging. The difference in fluorescence lifetime variation between the sexes is consistent with the notion that female animals alter the metabolism of sperm cells during storage. It is not consistent, however, with the idea that sperm metabolism represents a sexually selected character that provides females with information about the male genotype. 相似文献
2.
UE Reinhardt 《Canadian Metallurgical Quarterly》1994,13(4):22-24
The microflora of the large intestine in patients with odontogenic phlegmons of different localization were studied. 80.8% of such patients were found to have microecological disturbances, characterized by a decrease in the number of bacteria belonging to the genera Bifidobacterium, Lactobacillus, Enterococcus and Bacteroides and by an increase in the number of opportunistic microorganisms. 相似文献
3.
RA Reinhardt MP Masada GK Johnson LM DuBois GJ Seymour AC Allison 《Canadian Metallurgical Quarterly》1993,20(7):514-519
Interleukin (IL)-1 alpha and beta are cytokines which can mediate inflammatory, bone resorbing, and reparative effects in the periodontium, but few longitudinal data exist exploring their role following periodontal therapy. This study examined gingival crevicular fluid (GCF) concentrations of IL-1 alpha and IL-1 beta at sites with shallow sulci (SS) or inflamed moderate/advanced pockets (M/AP) before and 6 months after treatment with closed scaling/root planing (SC/RP) or papillary flap debridement (PFD), all in the same subject (n = 14 patients). No significant differences were noted in IL-1 alpha or beta concentrations (determined with two-site enzyme-linked immunosorbent assays) between SS and M/AP sites at baseline. While both therapies improved clinical parameters of periodontal disease, IL-1 alpha concentration increased significantly (p < 0.05) in M/AP-PFD sites 6 months after treatment, but were unchanged in other groups. IL-1 beta concentrations were numerically lower after therapy, except for a significant increase (p < 0.05) in M/AP-PFD sites. These data suggest that surgical wound healing in an inflamed, plaque-infected site (M/AP-PFD) results in prolonged production of IL-1, which may be a reflection of the extent of tissue trauma and delayed wound healing. In spite of increased IL-1 levels, these sites demonstrated significant short-term improvement in clinical attachment level (+ 1.8 mm, p < or = 0.001) postoperatively. 相似文献
4.
5.
6.
Otto Richter Thomas Schmidt Hand Büning-Pfaue und Dietrich Reinhardt 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1988,187(2):130-136
Zusammenfassung Es werden pharmakokinetische Modelle angegeben, um den Konzentrationsverlauf von Arzneimittelrückständen im Menschen zu berechnen, die mit der Nahrung aufgenommen werden. Dabei lassen sich zwei Kompartimentmodelle für die Kinetik in der Nahrung und im Menschen koppeln: Das erste System liefert die Anfangswerte (bzw. eine Folge von Anfangswerten) für das zweite System. Das Modell wird auf die Übertragung von Chloramphenicol durch Speisefische auf den Menschen und auf die Übertragung von Theophyin durch die Muttermilch auf gestillte Säuglinge angewendet. Durch Einführung einer günstigsten und ungünstigsten Parameterkombination werden Grenzverläufe für die Blutspiegel berechnet, die als Grundlage einer Rückstandsbewertung dienen können.
Residues of active substances following the consumption of contaminated food —Status report on the evaluation of residues based on two drugs
Summary Pharmacokinetic models are presented for the computation of time courses of blood levels of drugs in man following the consumption of contaminated food. Mathematically, two linear systems of differential equations are set up for the donor organism (e.g., trout) and for the recipient, (e.g., man), where the first system generates the initial conditions for the second. Models of this kind are applied to the transfer of chloramphenicol to man via carp and trout (which had previously been administered this drug) and to the transfer of theophylline to infants via breast milk. Limiting concentration profiles are computed by constructing the most favourable and most adverse combinations of parameters with respect to drug elimination in both the donor and recipient organism.相似文献
7.
8.
Leonel F. Murga Ying Wei Pierrette André James G. Clifton Dagmar Ringe Mary Jo Ondrechen 《Israel journal of chemistry》2004,44(1-3):299-308
Structural genomics initiatives are determining thousands of new protein structures. Many of these structures are of unknown function, and computational methods for the rapid determination of functional information from protein structure are needed. We present details of how functional information is obtained from the structure using THEMATICS (Theoretical Microscopic Titration Curves). THEMATICS is a computational procedure that gives information about chemical reactivity, based on solution of the Poisson-Boltzmann equations for the electrical potential function. We show how anomalies in predicted titration curves are established. We show further that when residues with anomalous predicted titration curves form a cluster in physical space, these residues tend to be very highly conserved across species and such clusters are reliable predictors of the active site. Results are given for ten enzymes; detailed results are shown for the enzymes triosephosphate isomerase (from chicken), 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (from E. coli), and papain (from papaya). 相似文献
9.
The question of how best to model rhythmic movements at self-selected amplitude-frequency combinations, and their variability, is a long-standing issue. This study presents a systematic analysis of a coupled oscillator system that has successfully accounted for the experimental result that humans' preferred oscillation frequencies closely correspond to the linear resonance frequencies of the biomechanical limb systems, a phenomenon known as resonance tuning or frequency scaling. The dynamics of the coupled oscillator model is explored by numerical integration in different areas of its parameter space, where a period doubling route to chaotic dynamics is discovered. It is shown that even in the regions of the parameter space with chaotic solutions, the model still effectively scales to the biomechanical oscillator's natural frequency. Hence, there is a solution providing for frequency scaling in the presence of chaotic variability. The implications of these results for interpreting variability as fundamentally stochastic or chaotic are discussed. 相似文献
10.
Driving Automotive User Interface Research 总被引:2,自引:0,他引:2
Cars offer an interesting but challenging microcosm for pervasive computing research and, in particular, for interaction with pervasive computing systems. Increasingly, researchers are looking at interactive applications in the car and investigating human-car interaction from a computer science—rather than an ergonomics or mechanical engineering—perspective. This article reports on the International Conference on Automotive User Interfaces and Interactive Vehicular Applications, wherein participants shared presentations on topics such as aesthetics, user interaction and distraction, safety, and driver monitoring. 相似文献