全文获取类型
收费全文 | 201793篇 |
免费 | 30858篇 |
国内免费 | 10674篇 |
专业分类
电工技术 | 13389篇 |
技术理论 | 12篇 |
综合类 | 15065篇 |
化学工业 | 40470篇 |
金属工艺 | 9963篇 |
机械仪表 | 11463篇 |
建筑科学 | 15076篇 |
矿业工程 | 4858篇 |
能源动力 | 5405篇 |
轻工业 | 22273篇 |
水利工程 | 4440篇 |
石油天然气 | 7114篇 |
武器工业 | 1711篇 |
无线电 | 25898篇 |
一般工业技术 | 28020篇 |
冶金工业 | 6585篇 |
原子能技术 | 2105篇 |
自动化技术 | 29478篇 |
出版年
2024年 | 789篇 |
2023年 | 2774篇 |
2022年 | 5565篇 |
2021年 | 7898篇 |
2020年 | 7127篇 |
2019年 | 7316篇 |
2018年 | 7620篇 |
2017年 | 8558篇 |
2016年 | 8501篇 |
2015年 | 10923篇 |
2014年 | 12867篇 |
2013年 | 15587篇 |
2012年 | 15304篇 |
2011年 | 15631篇 |
2010年 | 14638篇 |
2009年 | 13759篇 |
2008年 | 13354篇 |
2007年 | 12210篇 |
2006年 | 11231篇 |
2005年 | 9145篇 |
2004年 | 6914篇 |
2003年 | 6447篇 |
2002年 | 7111篇 |
2001年 | 6186篇 |
2000年 | 4538篇 |
1999年 | 3100篇 |
1998年 | 1663篇 |
1997年 | 1368篇 |
1996年 | 1144篇 |
1995年 | 909篇 |
1994年 | 720篇 |
1993年 | 510篇 |
1992年 | 467篇 |
1991年 | 354篇 |
1990年 | 239篇 |
1989年 | 203篇 |
1988年 | 144篇 |
1987年 | 103篇 |
1986年 | 73篇 |
1985年 | 51篇 |
1984年 | 33篇 |
1983年 | 21篇 |
1982年 | 41篇 |
1981年 | 30篇 |
1980年 | 55篇 |
1979年 | 26篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1959年 | 16篇 |
1951年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
61.
Nazir Kizzie‐Hayford Doris Jaros Yvonne Schneider Harald Rohm 《International Journal of Food Science & Technology》2015,50(2):381-388
A standard method for the extraction of tiger nut milk has been introduced. It has been shown that, although milling duration improves the yield of tiger nut milk solids and its nutrient composition, there is a quantifiable loss of nutrient in the pressing residue during milk extraction. Milling duration improved the colloidal stability of the milk against creaming during 16 h of storage. A higher milling intensity resulted in the aggregation of biological polymers which resulted in colloidal destabilisation. Milling improved the lightness and stability and reduced browning rate of the tiger nut milk during storage. This report is important for the production of tiger nut milk of consistent and comparable characteristics. Milling has been introduced as a processing method for the qualitative and quantitative modulation of the properties of tiger nut milk. It is recommended to develop further strategies to improve the colloidal stability of tiger nut milk as a beverage. 相似文献
62.
63.
64.
65.
Muntasir Hashim Farnoosh Farhad David Smyth‐Boyle Robert Akid Xiang Zhang Philip J. Withers 《工业材料与腐蚀》2019,70(11):2009-2019
The environmental performance of 316L grade stainless steel, in the form of tensile specimens containing a single corrosion pit with various aspect ratios, under cyclic loading in aerated chloride solutions is investigated in this study. Results from environmental tests were compared and contrasted with those obtained using finite element analysis (FEA). Fractography of the failed specimens obtained from experiments revealed that fatigue crack initiation took place at the base of the shallow pit. The crack initiation shifted towards the shoulder and the mouth of the pit for pits of increasing depth. This process is well predicted by FEA, as the strain contour maps show that strain is the highest around the centric strip of the pit. However, for shallow pits, local strain is uniformly distributed around that strip but begins to concentrate more towards the shoulder and the mouth region for increasingly deep pits. 相似文献
66.
In vivo Kinetic Biodistribution of Nano‐Sized Outer Membrane Vesicles Derived from Bacteria
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Su Chul Jang Sae Rom Kim Yae Jin Yoon Kyong‐Su Park Ji Hyun Kim Jaewook Lee Oh Youn Kim Eun‐Jeong Choi Dae‐Kyum Kim Dong‐Sic Choi Yoon‐Keun Kim Jaesung Park Dolores Di Vizio Yong Song Gho 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(4):456-461
Evaluation of kinetic distribution and behaviors of nanoparticles in vivo provides crucial clues into their roles in living organisms. Extracellular vesicles are evolutionary conserved nanoparticles, known to play important biological functions in intercellular, inter‐species, and inter‐kingdom communication. In this study, the first kinetic analysis of the biodistribution of outer membrane vesicles (OMVs)—bacterial extracellular vesicles—with immune‐modulatory functions is performed. OMVs, injected intraperitoneally, spread to the whole mouse body and accumulate in the liver, lung, spleen, and kidney within 3 h of administration. As an early systemic inflammation response, increased levels of TNF‐α and IL‐6 are observed in serum and bronchoalveolar lavage fluid. In addition, the number of leukocytes and platelets in the blood is decreased. OMVs and cytokine concentrations, as well as body temperature are gradually decreased 6 h after OMV injection, in concomitance with the formation of eye exudates, and of an increase in ICAM‐1 levels in the lung. Following OMV elimination, most of the inflammatory signs are reverted, 12 h post‐injection. However, leukocytes in bronchoalveolar lavage fluid are increased as a late reaction. Taken together, these results suggest that OMVs are effective mediators of long distance communication in vivo. 相似文献
67.
Yao‐Min Hung Neng‐Chyan Huang Jyh‐Seng Wang Shue‐Ren Wann 《Hemodialysis international. International Symposium on Home Hemodialysis》2015,19(2):344-346
Cases of isolated hepatic tuberculosis (TB) are rare. The diagnosis is often delayed or missed because of nonspecific symptoms and laboratory findings. Besides, the disease is extremely rare even in a country where TB is an alarming public health problem. This report demonstrates the difficulty in correctly diagnosing local hepatic TB. We report the case of a 62‐year‐old male patient with end‐stage renal disease treated with hemodialysis, who developed 2 months of abdominal distension and general anorexia, with hyperechoic hepatic lesions on ultrasound. Computed tomography suspected multiple liver tumors. The liver biopsy finally led to the diagnosis of TB of the liver without other involvements. We conclude that isolated hepatic TB is one of the rare forms of extrapulmonary TB in dialysis patients. A greater awareness of this rare clinical entity may prevent needless surgical interventions. 相似文献
68.
69.
摘要:为了研究300M超高强钢在中性盐雾环境中的腐蚀行为及腐蚀机制,采用失重法,宏观、微观腐蚀形貌分析,三维表面轮廓分析及电化学分析的研究方法,来表征腐蚀实验现象并进行分析。结果表明:300M超高强钢在中性盐雾环境中的腐蚀产物为FeOOH、Fe2O3、Fe(OH)3和Fe3O4;腐蚀速率随着腐蚀时间逐渐降低,腐蚀后期(72h)腐蚀速率降低50%;腐蚀初期以点蚀为主,点蚀坑通过横向扩展,逐渐发展为后期的均匀腐蚀,腐蚀表面形貌呈沟壑状;外腐蚀层对基体的保护能力很弱,Cr元素在锈层靠近基体的一侧偏聚使内腐蚀层具有一定的抗腐蚀性。 相似文献
70.
Weikang Dong Ruishi Qi Tiansheng Liu Yi Li Ning Li Ze Hua Zirui Gao Shuyuan Zhang Kaihui Liu Jiandong Guo Peng Gao 《Advanced materials (Deerfield Beach, Fla.)》2020,32(46):2002014
Hyperbolic phonon polaritons (HPhPs) in orthorhombic-phase molybdenum trioxide (α-MoO3) show in-plane hyperbolicity, great wavelength compression, and ultralong lifetime, therefore holding great potential in nanophotonic applications. However, its polaritonic response in the far-infrared (FIR) range remains unexplored due to challenges in experimental characterization. Here, monochromated electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM) is used to probe HPhPs in α-MoO3 in both mid-infrared (MIR) and FIR frequencies and correlate their behaviors with microstructures and orientations. It is found that low structural symmetry leads to various phonon modes and multiple Reststrahlen bands (RBs) over a broad spectral range (over 70 meV) and in different directions (55–63 meV and 119–125 meV along the b-axis, 68–106 meV along the c-axis, and 101–121 meV along the a-axis). These HPhPs can be selectively excited by controlling the direction of swift electrons. These findings provide new opportunities in nanophotonic and optoelectronic applications, such as directed light propagation, hyperlenses, and heat transfer. 相似文献