全文获取类型
收费全文 | 2530篇 |
免费 | 283篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 15篇 |
综合类 | 4篇 |
化学工业 | 830篇 |
金属工艺 | 64篇 |
机械仪表 | 85篇 |
建筑科学 | 34篇 |
矿业工程 | 1篇 |
能源动力 | 70篇 |
轻工业 | 466篇 |
水利工程 | 6篇 |
石油天然气 | 9篇 |
无线电 | 307篇 |
一般工业技术 | 529篇 |
冶金工业 | 175篇 |
原子能技术 | 28篇 |
自动化技术 | 193篇 |
出版年
2024年 | 4篇 |
2023年 | 46篇 |
2022年 | 87篇 |
2021年 | 153篇 |
2020年 | 82篇 |
2019年 | 89篇 |
2018年 | 109篇 |
2017年 | 119篇 |
2016年 | 133篇 |
2015年 | 115篇 |
2014年 | 162篇 |
2013年 | 161篇 |
2012年 | 189篇 |
2011年 | 224篇 |
2010年 | 163篇 |
2009年 | 137篇 |
2008年 | 121篇 |
2007年 | 93篇 |
2006年 | 75篇 |
2005年 | 78篇 |
2004年 | 71篇 |
2003年 | 42篇 |
2002年 | 42篇 |
2001年 | 21篇 |
2000年 | 30篇 |
1999年 | 20篇 |
1998年 | 56篇 |
1997年 | 48篇 |
1996年 | 28篇 |
1995年 | 23篇 |
1994年 | 17篇 |
1993年 | 13篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1977年 | 3篇 |
1976年 | 10篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1970年 | 1篇 |
1965年 | 2篇 |
排序方式: 共有2816条查询结果,搜索用时 0 毫秒
11.
We propose an asymmetric integral imaging method to adjust the resolution and depth of a three‐dimensional image. Our method is obtained by use of two lenticular sheets with different pitches fabricated under the same F/#. The asymmetric integral imaging is the generalized version of integral imaging, including both conventional integral imaging and one‐dimensional integral imaging. We present experimental results to test and verify the performance of our method computationally. 相似文献
12.
Eun‐Soo Park 《应用聚合物科学杂志》2008,110(3):1723-1729
Silicone rubber (SR) foams were prepared by the peroxide curing of a silicone compound with 2,4‐dichlorobenzoyl peroxide (DCBP), di‐t‐butyl peroxide (DTBP), or 2,5‐dimethyl‐2,5‐di(t‐butylperoxy) hexane (DBPH) in the presence of 2,2′‐azobisisobutyronitrile (AIBN) as a blowing agent. The cells were formed in the foam as a result of nitrogen produced by the decomposition of AIBN during the foaming process. The cell size, hardness, and tensile properties of the SR foams were examined as a function of the peroxide concentration. When the peroxide concentration increased, the hardness and tensile strength of the SR foams increased, whereas the cell size and elongation at break decreased. The antibacterial activity of the prepared foams was also evaluated via their effects on Staphylococcus aureus and Escherichia coli. The peroxide‐cured SR foams had antibacterial activity because a toxic residue was generated by the peroxide decomposition. The foam prepared by the AIBN/DCBP system showed more antibacterial activity than the AIBN/DBPH and AIBN/DTBP ones. However, after postcuring at 250°C for 2 h, the antibacterial activity of the SR foams significantly decreased. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
13.
The drawability of iodinated at solution before casting (IBC) polyvinyl alcohol films prepared by casting aqueous solutions of 10 wt % PVA containing 15.2, 39.8, 83.2, 117.0, and 140.1% was examined with a tensile tester at 20–60°C. The tensile behavior of IBC films showed that the yield and breaking loads were much lower, and the breaking elongation was even higher than those of the unoriented iodinated after casting (IAC) films as well as the untreated PVA films. The maximum draw ratios of the films with the weight gain of 15.2, 39.8, 83.2, 117, and 140.1% were 4.5, 5.5, 8.5, 8.0, and 7.5, respectively, which were achieved at 20°C in all. The crystallinity of all films increased by the maximum draw, regardless of crystallinity before drawing. The crystalline structure was recovered to the original PVA crystalline lattice by deiodination. Amorphous orientation and initial moduli increased with the maximum draw ratio, while the orientation of crystals was constant. The orientation and moduli increased up to the weight gain of 83.2%, whose highest draw ratio and initial modulus were 8.5 and of 7.1 GPa, respectively, and then decreased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献
14.
The authors tried to find the correlation between the occurrence of genital tract candidiasis in adolescents and some subjective and objective examination parameters. The highest correlation rates were found for pudendal pruritus, lower abdominal pains and early applied antibiotic therapy material: 188 adolescent girls. 相似文献
15.
16.
17.
T Saito S Kurumada Y Kawakami H Go T Uchiyama K Ueki 《Canadian Metallurgical Quarterly》1996,56(2):105-106
A modified surgical splint for Le Fort I osteotomies with transverse expansion is presented. The splint is made of a transpalatal stainless steel bar with acrylic abutment against the palatal surface of the molar and bicuspid tooth. It is rigid and renders excellent retention. It causes minimal patient discomfort, and oral hygiene is hardly compromised. 相似文献
18.
Tae Geun Kim Kyung Hyun Park Sung-Min Hwang Yong Kim Eun Kyu Kim Suk-Ki Min Si-Jeong Leem Jong-Il Jeon Jung-Ho Park Chang W.S.C. 《Quantum Electronics, IEEE Journal of》1998,34(8):1461-1468
GaAs-AlGaAs V-grooved inner stripe (VIS) quantum-well wire (QWW) lasers grown by metalorganic chemical vapor deposition with different current blocking configurations, n-blocking on p-substrate (VIPS), p-n-p-n blocking on n-substrate (VI(PN)nS) and p-blocking on n-substrate (VINS) have been fabricated and characterized. The VIPS QWW lasers show the most stable characteristics with effective current confinement: one of the lasers shows fundamental transverse mode, lasing up to 5 mW/facet, typical threshold current of 39.9 mA at 818.5 mm, an external differential quantum efficiency of 24%/facet, and characteristic temperature of 92 K. The current tuning rate was almost linear at 0.031 mm/mA, and the temperature tuning rate was measured to be 0.14 nm/°C. Comparison of the light output versus current characteristics of the lasers with different current blocking configurations is presented here 相似文献
19.
Verrucous carcinoma is a variant of squamous cell carcinoma and should be distinguished from benign papilloma and well-differentiated nonverrucous squamous cell carcinoma. It is rare tumor of the sinonasal tract. Occasionally, conventional squamous cell carcinomatous components may be seen in verrucous carcinoma. This entity is called a hybrid verrucous squamous cell carcinoma. We report a case of hybrid verrucous squamous cell carcinoma occurring in the nasal cavity and paranasal sinus of a 67-year-old male. The removed mass shows the typical feature of verrucous carcinoma, but focally conventional squamous cell carcinomatous area is also noted. The treatment of this case follows verrucous carcinoma, but close follow up is mandatory because it may potentially spread to regional lymph nodes in contrast to pure form of verrucous carcinoma. 相似文献
20.
Ivan Rodero Hariharasudhan Viswanathan Eun Kyung Lee Marc Gamell Dario Pompili Manish Parashar 《Journal of Grid Computing》2012,10(3):447-473
Virtualized datacenters and clouds are being increasingly considered for traditional High-Performance Computing (HPC) workloads that have typically targeted Grids and conventional HPC platforms. However, maximizing energy efficiency and utilization of datacenter resources, and minimizing undesired thermal behavior while ensuring application performance and other Quality of Service (QoS) guarantees for HPC applications requires careful consideration of important and extremely challenging tradeoffs. Virtual Machine (VM) migration is one of the most common techniques used to alleviate thermal anomalies (i.e., hotspots) in cloud datacenter servers as it reduces load and, hence, the server utilization. In this article, the benefits of using other techniques such as voltage scaling and pinning (traditionally used for reducing energy consumption) for thermal management over VM migrations are studied in detail. As no single technique is the most efficient to meet temperature/performance optimization goals in all situations, an autonomic approach that performs energy-efficient thermal management while ensuring the QoS delivered to the users is proposed. To address the problem of VM allocation that arises during VM migrations, an innovative application-centric energy-aware strategy for Virtual Machine (VM) allocation is proposed. The proposed strategy ensures high resource utilization and energy efficiency through VM consolidation while satisfying application QoS by exploiting knowledge obtained through application profiling along multiple dimensions (CPU, memory, and network bandwidth utilization). To support our arguments, we present the results obtained from an experimental evaluation on real hardware using HPC workloads under different scenarios. 相似文献