首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2523篇
  免费   61篇
  国内免费   5篇
电工技术   33篇
综合类   10篇
化学工业   523篇
金属工艺   76篇
机械仪表   53篇
建筑科学   50篇
能源动力   93篇
轻工业   136篇
水利工程   4篇
石油天然气   4篇
无线电   442篇
一般工业技术   455篇
冶金工业   295篇
原子能技术   16篇
自动化技术   399篇
  2023年   13篇
  2022年   55篇
  2021年   56篇
  2020年   20篇
  2019年   23篇
  2018年   34篇
  2017年   35篇
  2016年   51篇
  2015年   55篇
  2014年   80篇
  2013年   176篇
  2012年   118篇
  2011年   150篇
  2010年   140篇
  2009年   173篇
  2008年   137篇
  2007年   150篇
  2006年   103篇
  2005年   82篇
  2004年   83篇
  2003年   59篇
  2002年   72篇
  2001年   49篇
  2000年   44篇
  1999年   40篇
  1998年   123篇
  1997年   69篇
  1996年   60篇
  1995年   33篇
  1994年   40篇
  1993年   26篇
  1992年   25篇
  1991年   30篇
  1990年   20篇
  1989年   19篇
  1988年   10篇
  1987年   7篇
  1986年   11篇
  1985年   13篇
  1984年   16篇
  1983年   7篇
  1982年   11篇
  1981年   11篇
  1980年   9篇
  1979年   8篇
  1978年   5篇
  1977年   7篇
  1976年   6篇
  1973年   5篇
  1971年   4篇
排序方式: 共有2589条查询结果,搜索用时 0 毫秒
81.
ABSTRACT: Pork sticks were prepared by mixing pork chucks with various amounts of bisulfite-treated soy protein and microbial transglutaminase (MTGase) to evaluate the potential of using soy protein as meat binders. According to tensile strength, the favorable conditions for binding the restructured pork chunks were 5% soy protein containing 0.2% NaHSO3 and 20 unit MTGase/g, and the setting condition was 60 min at 40°C. The tensile strength and cooking yield of restructured pork sticks made with bisulfite-treated soy protein and MTGase were much higher than those of using salt, suggesting the high potential of using soy protein and MTGase as binders in products where NaCl reduction is desired.  相似文献   
82.
Metastasis is the primary cause of death from breast cancer. Cell migration and invasion play important roles in neoplastic metastasis. The insulin‐like growth factor (IGF‐1) stimulates cell migration through activation of PI‐3K/Akt signaling pathway. IGF‐1 induces the tumorigenicity of many types of cancer cells and is critical for metastatic cell spread in estrogen receptor (ER)‐negative breast‐cancer cells. Matrix metalloproteinase‐2 (MMP‐2) is a key enzyme in the degradation of extracellular matrices and its expression has been dysregulated in breast cancer invasion and metastasis. Resveratrol exhibited potential anticarcinogenic activities in several studies. However, the inhibitory effects of resveratrol on the expression of MMP‐2, migration and invasion of breast‐cancer cell have not been demonstrated yet. In the present study, we investigated the anti‐invasive mechanism of resveratrol in human breast cancer MDA‐MB 435cells. Here, we showed that IGF‐1 is a potent stimulant of the migration of ER‐negative human breast‐cancer cells. Resveratrol could inhibit IGF‐1‐mediated cell migration of MDA‐MB 435 in vitro. The inhibitory effect of resveratrol was mediated in part through the suppression of the activation of PI‐3K/Akt signaling pathway. Furthermore, IGF‐1‐mediated expression of MMP‐2 was significantly inhibited by resveratrol in concomitance with alteration of cell invasion.  相似文献   
83.
To survey the hygienic quality and freshness of fresh fish and shellfish, 533 specimens of fish and shellfish were collected from fishing piers, traditional markets and supermarkets (including warehouses) in northern Taiwan during the winter (January-February) and summer (July-August) seasons for hygienic quality and freshness examinations. The indicators included total bacterial count, fecal coliform, Escherichia coli, volatile basic nitrogen (VBN) and K value judged from ATP-related compounds. It was found that the hygienic quality and freshness of fish and shellfish decreased in summer, especially for clam and mussel. The ratio of unacceptable hygienic quality or freshness of fish and shellfish was the highest in fecal coliform, followed by E. coli and others. The fecal coliform count in products from the traditional markets was the highest, followed by those from supermarkets and fishing piers. Secondary contamination seems to be the most important problem for hygienic quality and freshness of fish and shellfish.  相似文献   
84.
Oral submucous fibrosis (OSF) is known as a potentially malignant disorder, which may result from chemical irritation due to areca nuts (such as arecoline). Emerging evidence suggests that fibrogenesis and carcinogenesis are regulated by the interaction of long noncoding RNAs (lncRNAs) and microRNAs. Among these regulators, profibrotic lncRNA H19 has been found to be overexpressed in several fibrosis diseases. Here, we examined the expression of H19 in OSF specimens and its functional role in fibrotic buccal mucosal fibroblasts (fBMFs). Our results indicate that the aberrantly overexpressed H19 contributed to higher myofibroblast activities, such as collagen gel contractility and migration ability. We also demonstrated that H19 interacted with miR-29b, which suppressed the direct binding of miR-29b to the 3′-untranslated region of type I collagen (COL1A1). We showed that ectopic expression of miR-29b ameliorated various myofibroblast phenotypes and the expression of α-smooth muscle actin (α-SMA), COL1A1, and fibronectin (FN1) in fBMFs. In OSF tissues, we found that the expression of miR-29b was downregulated and there was a negative correlation between miR-29b and these fibrosis markers. Lastly, we demonstrate that arecoline stimulated the upregulation of H19 through the transforming growth factor (TGF)-β pathway. Altogether, this study suggests that increased TGF-β secretion following areca nut chewing may induce the upregulation of H19, which serves as a natural sponge for miR-29b and impedes its antifibrotic effects.  相似文献   
85.
86.
Ferroptosis is a newly identified mode of programmed cell death characterized by iron-associated accumulation of lipid peroxides. Emerging research on ferroptosis has suggested its implication in tumorigenesis and stemness of cancer. On the other hand, non-coding RNAs have been shown to play a pivotal role in the modulation of various genes that affect the progression of cancer cells and ferroptosis. In this review, we summarize recent advances in the theoretical modeling of ferroptosis and its relationship between non-coding RNAs and head and neck cancers. Aside from the significance of ferroptosis-related non-coding RNAs in prognostic relevance, we also review how these non-coding RNAs participate in the regulation of iron, lipid metabolism, and reactive oxygen species accumulation. We aim to provide a thorough grounding in the function of ferroptosis-related non-coding RNAs based on current knowledge in an effort to develop effective therapeutic strategies for head and neck cancers.  相似文献   
87.
Hsiehchen  David  Espinoza  Magdalena  Hsieh  Antony 《Scientometrics》2018,117(1):391-407
Scientometrics - The expanding presence of multinational research teams highlights the importance of characterizing the outcomes of international collaboration. Herein, we characterize the...  相似文献   
88.
Zhou  Qingguo  Feng  Fang  Shen  Zebang  Zhou  Rui  Hsieh  Meng-Yen  Li  Kuan-Ching 《Multimedia Tools and Applications》2019,78(3):3529-3552
Multimedia Tools and Applications - With the increasing number of malicious attacks, the way how to detect malicious Apps has drawn attention in mobile technology market. In this paper, we proposed...  相似文献   
89.
Microsystem Technologies - Error-tolerance has been proposed as a new method to increase effective yield of a system. The basic idea is that faulty chips might be still acceptable as long as their...  相似文献   
90.
The eutectic (Cr,Fe)-(Cr,Fe)23C6 showed a triaxial fishbone structure and could be categorized as a “complex regular structure”. In this study, the lattice relations of the fishbone (Cr,Fe)23C6 were examined and the solidification process was observed using a transmission electron microscope and a confocal laser scanning microscope. For one of the three fish bones in a eutectic cell, parallel (Cr,Fe)23C6 lamellas at one side of the spine had the same lattice direction, as did those in the (Cr,Fe) phase. The lattices of neighboring (Cr,Fe)23C6 and (Cr,Fe) phases were not coherent. Lamellar (Cr,Fe)23C6 on opposite sides of a spine had different lattice directions, and their lattice boundary was in the spine. By using the confocal laser scanning microscope, the solidification of lamellar eutectic structure could be observed. At the low cooling rate of 5 o C·min-1, parallel lamellas would grow thick blocks instead of thin plates. To obtain a thin lamellar eutectic structure, the cooling rate should be higher, like the rate in welding.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号