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1.
Eszter Hargittai 《Journal of Computer-Mediated Communication》2007,12(3):769-777
Search engines are some of the most popular destinations on the Web—understandably so, given the vast amounts of information available to users and the need for help in sifting through online content. While the results of significant technical achievements, search engines are also embedded in social processes and institutions that influence how they function and how they are used. This special theme section of the Journal of Computer-Mediated Communication explores these non-technical aspects of search engines and their uses. 相似文献
2.
Chao AC Ziadeh BI Diau GY Wijendran V Sarkadi-Nagy E Hsieh AT Nathanielsz PW Brenna JT 《Lipids》2003,38(4):425-429
One of the major survival challenges of premature birth is production of lung surfactant. The lipid component of surfactant,
dipalmitoyl PC (DPPC), increases in concentration in the period before normal term birth via a net shift in FA composition away from unsaturates. We investigated the influence of dietary DHA and arachidonic acid (AA)
on lung FA composition and DPPC concentration in term and preterm baboons. Pregnant animals/neonates were randomized to one
of four groups: breast-fed (B), term formula-fed (T−), preterm formulafed (P−), and preterm fed formula supplemented with DHA-AA (P+). Breast milk contained 0.68%wt DHA and the P+ group formula contained 0.61%wt DHA. In the preterm groups (P− and P+), pregnant females received a course of antenatal corticosteroids. At the adjusted age of 4 wk, neonate lung tissue was harvested,
and FA composition and DPPC were analyzed. Palmitate was ∼28%wt of lung total FA and no significant differences were found
among the four treatment groups. In contrast, DPPC in the B group lung tissue was significantly greater than DPPC in the unsupplemented
groups, but not compared with the P+ group. The B and P+ groups were not significantly different in DHA and AA, but were different compared with the unsupplemented (T, P−) groups. These results indicate that LCP supplementation increases lung DHA and AA, without compromising overall lung 16∶0
or DPPC. The shift in FA composition toward greater unsaturation in the groups consuming LCP supported improved surfactant
lipid concentration in preterm neonate lungs. 相似文献
3.
Clustering Empirical Failure Rate Curves for Reliability Prediction Purposes in the Case of Consumer Electronic Products 下载免费PDF全文
József Dombi Tamás Jónás Zsuzsanna Eszter Tóth 《Quality and Reliability Engineering International》2016,32(3):1071-1083
In this paper, a methodology based on the combination of time series modeling and soft computational methods is presented to model and forecast bathtub‐shaped failure rate data of newly marketed consumer electronics. The time‐dependent functions of historical failure rates are typified by parameters of an analytic model that grabs the most important characteristics of these curves. The proposed approach is also verified by the presentation of an industrial application brought along at an electrical repair service provider company. The prediction capability of the introduced methodology is compared with moving average‐based and exponential smoothing‐based forecasting methods. According to the results of comparison, the presented method can be considered as a viable alternative reliability prediction technique. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
4.
Controlled surface modification of the PDMS (polydimethylsiloxane) was developed and studied in this work to develop autonomous capillary-driven microfluidic system to be applied in bioanalytical devices. The characteristics of the PDMS surfaces were modified by embedding adequate surfactant molecules in the polymer matrix to be moved onto the free surface by diffusion. The change of the surface characteristics was studied considering the expected performance in autonomous biomicrofluidic applications and the influence on non-specific human blood protein binding also. The method was evaluated from technological aspects also, as the integrability of the microfluidic system, considering the previously published results critically. Compositions were defined to be adequate for fabrication autonomous capillary system with enhanced transport efficiency and moderated non-specific protein adsorption. 相似文献
5.
Dina Kata Ilona Grf Zsfia Hoyk Eszter Ducza Mria A. Deli Istvn Zupk Imre Fldesi 《International journal of molecular sciences》2022,23(16)
Estrogens regulate a variety of neuroendocrine, reproductive and also non-reproductive brain functions. Estradiol biosynthesis in the central nervous system (CNS) is catalyzed by the enzyme aromatase, which is expressed in several brain regions by neurons, astrocytes and microglia. In this study, we performed a complex fluorescent immunocytochemical analysis which revealed that aromatase is colocalized with the nuclear stain in glial fibrillary acidic protein (GFAP) positive astrocytes in cell cultures. Confocal immunofluorescent Z-stack scanning analysis confirmed the colocalization of aromatase with the nuclear DAPI signal. Nuclear aromatase was also detectable in the S100β positive astrocyte subpopulation. When the nuclear aromatase signal was present, estrogen receptor alpha was also abundant in the nucleus. Immunostaining of frozen brain tissue sections showed that the nuclear colocalization of the enzyme in GFAP-positive astrocytes is also detectable in the adult rat brain. CD11b/c labelled microglial cells express aromatase, but the immunopositive signal was distributed only in the cytoplasm both in the ramified and amoeboid microglial forms. Immunostaining of rat ovarian tissue sections and human granulosa cells revealed that aromatase was present only in the cytoplasm. This novel observation suggests a new unique mechanism in astrocytes that may regulate certain CNS functions via estradiol production. 相似文献
6.
Ewa Szczurowska Eszter Sznti-Pintr Nikolai Chetverikov Alena Randkov Eva Kudov Jan Jakubík 《International journal of molecular sciences》2023,24(1)
Muscarinic acetylcholine receptors expressed in the central nervous system mediate various functions, including cognition, memory, or reward. Therefore, muscarinic receptors represent potential pharmacological targets for various diseases and conditions, such as Alzheimer’s disease, schizophrenia, addiction, epilepsy, or depression. Muscarinic receptors are allosterically modulated by neurosteroids and steroid hormones at physiologically relevant concentrations. In this review, we focus on the modulation of muscarinic receptors by neurosteroids and steroid hormones in the context of diseases and disorders of the central nervous system. Further, we propose the potential use of neuroactive steroids in the development of pharmacotherapeutics for these diseases and conditions. 相似文献
7.
8.
Emese Rka Blint Gabriella Fr Balzs Kui Zsolt Balla Eszter Sra Kormnyos Erik Mrk Orjn Brigitta Tth Gyngyi Horvth Edina Szcs Sndor Benyhe Eszter Ducza Petra Pallagi Jzsef Malth Viktria Venglovecz Pter Hegyi Lrnd Kiss Zoltn Rakonczay Jr. 《International journal of molecular sciences》2022,23(3)
Opioids are widely used for the pain management of acute pancreatitis (AP), but their impact on disease progression is unclear. Therefore, our aim was to study the effects of clinically relevant opioids on the severity of experimental AP. Various doses of fentanyl, morphine, or buprenorphine were administered as pre- and/or post-treatments in rats. Necrotizing AP was induced by the intraperitoneal injection of L-ornithine-HCl or intra-ductal injection of Na-taurocholate, while intraperitoneal caerulein administration caused edematous AP. Disease severity was determined by laboratory and histological measurements. Mu opioid receptor (MOR) expression and function was assessed in control and AP animals. MOR was expressed in both the pancreas and brain. The pancreatic expression and function of MOR were reduced in AP. Fentanyl post-treatment reduced necrotizing AP severity, whereas pre-treatment exacerbated it. Fentanyl did not affect the outcome of edematous AP. Morphine decreased vacuolization in edematous AP, while buprenorphine pre-treatment increased pancreatic edema during AP. The overall effects of morphine on disease severity were negligible. In conclusion, the type, dosing, administration route, and timing of opioid treatment can influence the effects of opioids on AP severity. Fentanyl post-treatment proved to be beneficial in AP. Clinical studies are needed to determine which opioids are best in AP. 相似文献
9.
A. W. R. H. Teunissen E. Holub J. Van Der Hucht J. A. Van Den Berg H. Y. Steensma 《Yeast (Chichester, England)》1993,9(4):423-427
The cloned part of the flocculation gene FLO1 of Saccharomyces cerevisiae (Teunissen, A.W.R.H., van den Berg, J.A. and Steensma, H.Y. (1993). Physical localization of the flocculation gene FLO1 on chromosome I of Saccharomyces cerevisiae, Yeast, in press) has been sequenced. The sequence contains a large open reading frame of 2685 bp. The amino acid sequence of the putative protein reveals a serine- and threonine-rich C-terminus (46%), the presence of repeated sequences and a possible secretion signal at the N-terminus. Although the sequence is not complete (we assume the missing fragment consists of repeat units), these data strongly suggest that the protein is located in the cell wall, and thus may be directly involved in the flocculation process. 相似文献
10.
Eszter Hargittai 《Journal of Computer-Mediated Communication》2007,13(1):276-297
Are there systematic differences between people who use social network sites and those who stay away, despite a familiarity with them? Based on data from a survey administered to a diverse group of young adults, this article looks at the predictors of SNS usage, with particular focus on Facebook, MySpace, Xanga, and Friendster. Findings suggest that use of such sites is not randomly distributed across a group of highly wired users. A person’s gender, race and ethnicity, and parental educational background are all associated with use, but in most cases only when the aggregate concept of social network sites is disaggregated by service. Additionally, people with more experience and autonomy of use are more likely to be users of such sites. Unequal participation based on user background suggests that differential adoption of such services may be contributing to digital inequality. 相似文献