全文获取类型
收费全文 | 2188篇 |
免费 | 126篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 16篇 |
综合类 | 4篇 |
化学工业 | 451篇 |
金属工艺 | 18篇 |
机械仪表 | 33篇 |
建筑科学 | 113篇 |
矿业工程 | 6篇 |
能源动力 | 36篇 |
轻工业 | 229篇 |
水利工程 | 33篇 |
石油天然气 | 2篇 |
武器工业 | 1篇 |
无线电 | 169篇 |
一般工业技术 | 271篇 |
冶金工业 | 670篇 |
原子能技术 | 7篇 |
自动化技术 | 257篇 |
出版年
2023年 | 17篇 |
2022年 | 58篇 |
2021年 | 81篇 |
2020年 | 32篇 |
2019年 | 42篇 |
2018年 | 48篇 |
2017年 | 41篇 |
2016年 | 60篇 |
2015年 | 54篇 |
2014年 | 75篇 |
2013年 | 95篇 |
2012年 | 85篇 |
2011年 | 147篇 |
2010年 | 117篇 |
2009年 | 102篇 |
2008年 | 96篇 |
2007年 | 113篇 |
2006年 | 69篇 |
2005年 | 75篇 |
2004年 | 67篇 |
2003年 | 49篇 |
2002年 | 50篇 |
2001年 | 37篇 |
2000年 | 35篇 |
1999年 | 35篇 |
1998年 | 96篇 |
1997年 | 72篇 |
1996年 | 46篇 |
1995年 | 38篇 |
1994年 | 32篇 |
1993年 | 39篇 |
1992年 | 18篇 |
1991年 | 15篇 |
1990年 | 21篇 |
1989年 | 19篇 |
1988年 | 28篇 |
1987年 | 20篇 |
1986年 | 10篇 |
1985年 | 17篇 |
1984年 | 16篇 |
1983年 | 12篇 |
1982年 | 6篇 |
1981年 | 12篇 |
1980年 | 12篇 |
1979年 | 16篇 |
1978年 | 7篇 |
1977年 | 11篇 |
1976年 | 15篇 |
1975年 | 7篇 |
1974年 | 11篇 |
排序方式: 共有2316条查询结果,搜索用时 15 毫秒
51.
Emotions have a political dimension in that judgments regarding when and how emotion should be felt and shown are interpreted in the interests of regulating the organization and functioning of social groups. This article argues that claims to authenticity and legitimacy of one's self-identity or group identity are at stake in the everyday politics of emotion. A brief discussion of the study of sex differences in the 19th century illustrates how emotion politics can saturate even scientific inquiry. Three ways in which there is a political dimension to socially appropriate emotion in contemporary life are then discussed: (a) Is the emotion the "wrong" emotion for the situation? (b) How are competing standards for emotional experience and expression managed? and (c) What constitutes the boundary between "too much" and "too little" emotion? The author concludes by considering the relevance of emotion politics to research on emotion. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
52.
Schopp Laura H.; Johnstone Brick; Reid-Arndt Stephanie 《Canadian Metallurgical Quarterly》2005,36(2):158
Rural psychologists are frontline primary behavioral health care providers for nearly 60 million Americans, but they face limited access to peer consultation and continuing education. This article describes a program that matched 70 rehabilitation inpatients who had new brain injury with rural clinicians from patients' home communities. Neuropsychologists provided one-on-one training for clinicians through telehealth video teleconferencing. Clinicians showed gains in brain injury knowledge, and clients rated trained providers higher than untrained providers. Families seeking brain injury services can connect with these trained rural providers through a Web site, which receives more than 800 hits per month. Telehealth offers potential for rural clinicians to receive support, reduce professional isolation, gain working knowledge of specialty conditions, and deliver high-quality services for their rural clients. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
53.
A real-time vision module for interactive perceptual agents 总被引:2,自引:0,他引:2
Bruce A. Maxwell Nathaniel Fairfield Nikolas Johnson Pukar Malla Paul Dickson Suor Kim Stephanie Wojtkowski Thomas Stepleton 《Machine Vision and Applications》2003,14(1):72-82
Abstract. Interactive robotics demands real-time visual information about the environment. Real-time vision processing, however, places
a heavy load on the robot's limited resources, which must accommodate multiple other processes running simultaneously. This
paper describes a vision module capable of providing real-time information from ten or more operators while maintaining at
least a 20-Hz frame rate and leaving sufficient processor time for a robot's other capabilities. The vision module uses a
probabilistic scheduling algorithm to ensure both timely information flow and a fast frame capture. In addition, it tightly
integrates the vision operators with control of a pan-tilt-zoom camera. The vision module makes its information available
to other modules in the robot architecture through a shared memory structure. The information provided by the vision module
includes the operator information along with a time stamp indicating information relevance. Because of this design, our robots
are able to react in a timely manner to a wide variety of visual events. 相似文献
54.
Infant rats exhibit sensitive-period odor learning characterized by olfactory bulb neural changes and odor preference acquisitions critical for survival. This sensitive period is coincident with low endogenous corticosterone (CORT) levels and stress hyporesponsivity. The authors hypothesized that low corticosterone levels modulate sensitive-period learning. They assessed the effects of manipulating CORT levels by increasing and removing CORT during (Postnatal Day 8) and after (Postnatal Day 12) the sensitive period. Results show that (a) exogenous CORT prematurely ends sensitive-period odor-shock-induced preferences; (b) adrenalectomy developmentally extends the sensitive period as indicated by odor-shock-induced odor-preference learning in older pups, whereas CORT replacement can reinstate fear learning; and (c) CORT manipulation modulates olfactory bulb correlates of sensitive-period odor learning in a manner consistent with behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
55.
Goodhew Stephanie C.; Visser Troy A. W.; Lipp Ottmar V.; Dux Paul E. 《Canadian Metallurgical Quarterly》2011,37(2):588
In object substitution masking (OSM) a sparse, temporally trailing 4-dot mask impairs target identification, even though it has different contours from, and does not spatially overlap with the target. Here, we demonstrate a previously unknown characteristic of OSM: Observers show reduced masking at prolonged (e.g., 640 ms) relative to intermediate mask durations (e.g., 240 ms). We propose that with prolonged exposure, the mask's visual representation is consolidated, which allows processing of the lingering target icon to be reinitiated, thereby improving performance. Our findings suggest that when the visual system is confronted with 2 temporally contiguous stimuli, although one may initially gain access to consciousness above the other, the “losing” stimulus is not irreversibly lost to awareness. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
56.
Ultra‐fast thermal annealing of thin films with annealing times of few milliseconds are faster und more energy efficient than conventional furnace annealing methods. By using flash lamp annealing, only the surface is heated while the substrate remains cold. This allows the refinement of indium‐tin‐oxide films on rigid and ultra‐thin flexible glass and improves their conductivity and transmittance. 相似文献
57.
Redona Hafizi Faik Imeri Bisera Stepanovska Tanturovska Roxana Manaila Stephanie Schwalm Sandra Trautmann Roland H. Wenger Josef Pfeilschifter Andrea Huwiler 《International journal of molecular sciences》2022,23(11)
Erythropoietin (Epo) is a crucial hormone regulating red blood cell number and consequently the hematocrit. Epo is mainly produced in the kidney by interstitial fibroblast-like cells. Previously, we have shown that in cultures of the immortalized mouse renal fibroblast-like cell line FAIK F3-5, sphingosine 1-phosphate (S1P), by activating S1P1 and S1P3 receptors, can stabilize hypoxia-inducible factor (HIF)-2α and upregulate Epo mRNA and protein synthesis. In this study, we have addressed the role of intracellular iS1P derived from sphingosine kinases (Sphk) 1 and 2 on Epo synthesis in F3-5 cells and in mouse primary cultures of renal fibroblasts. We show that stable knockdown of Sphk2 in F3-5 cells increases HIF-2α protein and Epo mRNA and protein levels, while Sphk1 knockdown leads to a reduction of hypoxia-stimulated HIF-2α and Epo protein. A similar effect was obtained using primary cultures of renal fibroblasts isolated from wildtype mice, Sphk1−/−, or Sphk2−/− mice. Furthermore, selective Sphk2 inhibitors mimicked the effect of genetic Sphk2 depletion and also upregulated HIF-2α and Epo protein levels. The combined blockade of Sphk1 and Sphk2, using Sphk2−/− renal fibroblasts treated with the Sphk1 inhibitor PF543, resulted in reduced HIF-2α and Epo compared to the untreated Sphk2−/− cells. Exogenous sphingosine (Sph) enhanced HIF-2α and Epo, and this was abolished by the combined treatment with the selective S1P1 and S1P3 antagonists NIBR-0213 and TY52156, suggesting that Sph was taken up by cells and converted to iS1P and exported to then act in an autocrine manner through S1P1 and S1P3. The upregulation of HIF-2α and Epo synthesis by Sphk2 knockdown was confirmed in the human hepatoma cell line Hep3B, which is well-established to upregulate Epo production under hypoxia. In summary, these data show that sphingolipids have diverse effects on Epo synthesis. While accumulation of intracellular Sph reduces Epo synthesis, iS1P will be exported to act through S1P1+3 to enhance Epo synthesis. Furthermore, these data suggest that selective inhibition of Sphk2 is an attractive new option to enhance Epo synthesis and thereby to reduce anemia development in chronic kidney disease. 相似文献
58.
Hang-Soo Park Rishi Man Chugh Melissa R. Pergande Esra Cetin Hiba Siblini Sahar Esfandyari Stephanie M. Cologna Ayman Al-Hendy 《International journal of molecular sciences》2022,23(9)
Polycystic ovary syndrome (PCOS) is the most common endocrine and metabolic disorder in reproductive-aged women, and it typically involves elevated androgen levels. Recently, it has been reported that human bone marrow mesenchymal stem cells (hBM-MSCs) can regulate androgen synthesis pathways. However, the details of the mechanism are still unclear. hBM-MSC-derived secreted factors (the secretome) are promising sources of cell-based therapy as they consist of various types of proteins. It is thus important to know which proteins interact with disease-implicated biomolecules. This work aimed to investigate which secretome components contain the key factor that inhibits testosterone synthesis. In this study, we fractionated hBM-MSC-conditioned media into three fractions based on their molecular weights and found that, of the three fractions, one had the ability to inhibit the androgen-producing genes efficiently. We also analyzed the components of this fraction and established a protein profile of the hBM-MSC secretome, which was shown to inhibit androgen synthesis. Our study describes a set of protein components present in the hBM-MSC secretome that can be used therapeutically to treat PCOS by regulating androgen production for the first time. 相似文献
59.
Tom Schreiner Lisa Allnoch Georg Beythien Katarzyna Marek Kathrin Becker Dirk Schaudien Stephanie Stanelle-Bertram Berfin Schaumburg Nancy Mounogou Kouassi Sebastian Beck Martin Zickler Gülsah Gabriel Wolfgang Baumgrtner Federico Armando Malgorzata Ciurkiewicz 《International journal of molecular sciences》2022,23(9)
Similar to many other respiratory viruses, SARS-CoV-2 targets the ciliated cells of the respiratory epithelium and compromises mucociliary clearance, thereby facilitating spread to the lungs and paving the way for secondary infections. A detailed understanding of mechanism involved in ciliary loss and subsequent regeneration is crucial to assess the possible long-term consequences of COVID-19. The aim of this study was to characterize the sequence of histological and ultrastructural changes observed in the ciliated epithelium during and after SARS-CoV-2 infection in the golden Syrian hamster model. We show that acute infection induces a severe, transient loss of cilia, which is, at least in part, caused by cilia internalization. Internalized cilia colocalize with membrane invaginations, facilitating virus entry into the cell. Infection also results in a progressive decline in cells expressing the regulator of ciliogenesis FOXJ1, which persists beyond virus clearance and the termination of inflammatory changes. Ciliary loss triggers the mobilization of p73+ and CK14+ basal cells, which ceases after regeneration of the cilia. Although ciliation is restored after two weeks despite the lack of FOXJ1, an increased frequency of cilia with ultrastructural alterations indicative of secondary ciliary dyskinesia is observed. In summary, the work provides new insights into SARS-CoV-2 pathogenesis and expands our understanding of virally induced damage to defense mechanisms in the conducting airways. 相似文献
60.