全文获取类型
收费全文 | 722篇 |
免费 | 30篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 8篇 |
综合类 | 1篇 |
化学工业 | 164篇 |
金属工艺 | 15篇 |
机械仪表 | 20篇 |
建筑科学 | 21篇 |
能源动力 | 15篇 |
轻工业 | 46篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 91篇 |
一般工业技术 | 161篇 |
冶金工业 | 113篇 |
原子能技术 | 3篇 |
自动化技术 | 94篇 |
出版年
2023年 | 6篇 |
2022年 | 15篇 |
2021年 | 20篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2018年 | 24篇 |
2017年 | 30篇 |
2016年 | 30篇 |
2015年 | 16篇 |
2014年 | 28篇 |
2013年 | 46篇 |
2012年 | 27篇 |
2011年 | 38篇 |
2010年 | 25篇 |
2009年 | 36篇 |
2008年 | 32篇 |
2007年 | 27篇 |
2006年 | 23篇 |
2005年 | 15篇 |
2004年 | 15篇 |
2003年 | 7篇 |
2002年 | 13篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 20篇 |
1997年 | 16篇 |
1996年 | 18篇 |
1995年 | 14篇 |
1994年 | 16篇 |
1993年 | 17篇 |
1992年 | 11篇 |
1991年 | 21篇 |
1990年 | 15篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 10篇 |
1978年 | 3篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1974年 | 2篇 |
1973年 | 3篇 |
排序方式: 共有754条查询结果,搜索用时 15 毫秒
1.
Sundaram Vickram Karunakaran Rohini Subramanian Srinivasan David Nancy Veenakumari Kumar Archana Krishnan Anbarasu Palanivelu Jeyanthi Sundaram Thanigaivel Govindarajan Gulothungan Nanmaran Rajendiran Padmalayam Sadanandan Srikumar 《International journal of molecular sciences》2021,22(4)
Zinc (Zn), the second-most necessary trace element, is abundant in the human body. The human body lacks the capacity to store Zn; hence, the dietary intake of Zn is essential for various functions and metabolism. The uptake of Zn during its transport through the body is important for proper development of the three major accessory sex glands: the testis, epididymis, and prostate. It plays key roles in the initial stages of germ cell development and spermatogenesis, sperm cell development and maturation, ejaculation, liquefaction, the binding of spermatozoa and prostasomes, capacitation, and fertilization. The prostate releases more Zn into the seminal plasma during ejaculation, and it plays a significant role in sperm release and motility. During the maternal, labor, perinatal, and neonatal periods, the part of Zn is vital. The average dietary intake of Zn is in the range of 8–12 mg/day in developing countries during the maternal period. Globally, the dietary intake of Zn varies for pregnant and lactating mothers, but the average Zn intake is in the range of 9.6–11.2 mg/day. The absence of Zn and the consequences of this have been discussed using critical evidence. The events and functions of Zn related to successful fertilization have been summarized in detail. Briefly, our current review emphasizes the role of Zn at each stage of human reproduction, from the spermatogenesis process to childbirth. The role of Zn and its supplementation in in vitro fertilization (IVF) opens opportunities for future studies on reproductive biology. 相似文献
2.
3.
4.
Gunapala S.D. Bundara S.V. Liu J.K. Winn Hong Mani Sundaram Maker P.D. Muller R.E. Shott C.A. Carralejo R. 《Electron Devices, IEEE Transactions on》1998,45(9):1890-1895
A 9-μm cutoff 640×486 snap-shot quantum well infrared photodetector (QWIP) camera has been demonstrated. The performance of this QWIP camera is reported including indoor and outdoor imaging. The noise equivalent differential temperature (NEΔT) of 36 mK has been achieved at 300 K background with f/2 optics. This is in good agreement with expected focal plane array sensitivity due to the practical limitations on charge handling capacity of the multiplexer, read noise, bias voltage, and operating temperature 相似文献
5.
Hyun-Ho Choi Sang-Yoon Lee Il-Yoon Choi Hyo-Nam Cho Sankaran Mahadevan 《Reliability Engineering & System Safety》2006,91(6):674-688
Until now, in many forensic reports, the failure cause assessments are usually carried out by a deterministic approach so far. However, it may be possible for the forensic investigation to lead to unreasonable results far from the real collapse scenario, because the deterministic approach does not systematically take into account any information on the uncertainties involved in the failures of structures.Reliability-based failure cause assessment (reliability-based forensic engineering) methodology is developed which can incorporate the uncertainties involved in structural failures and structures, and to apply them to the collapsed bridge in order to identify the most critical failure scenario and find the cause that triggered the bridge collapse. Moreover, to save the time and cost of evaluation, an algorithm of automated event tree analysis (ETA) is proposed and possible to automatically calculate the failure probabilities of the failure events and the occurrence probabilities of failure scenarios. Also, for reliability analysis, uncertainties are estimated more reasonably by using the Bayesian approach based on the experimental laboratory testing data in the forensic report. For the applicability, the proposed approach is applied to the Hang-ju Grand Bridge, which collapsed during construction, and compared with deterministic approach. 相似文献
6.
Andersson L.I. Rudberg B.G.R. Lewin P.T. Reed M.D. Planer S.M. Sundaram S.L. 《Solid-State Circuits, IEEE Journal of》1995,30(3):210-218
High-speed multiplexers, demultiplexers, frequency dividers, mixers, and amplifiers are key electronic components in high-speed fiber-optic communications systems such as SONET/SDH. In this paper, we present several important digital and analog integrated circuits (IC) which have been developed for use in SONET/SDH 10 Gb/s optical communication links. The circuits have been fabricated in MOSAIC 5E, an advanced silicon bipolar technology (fT=26 GHz). The resulting chipset which amounts to a total of 10 IC's consists of multiplexers, demultiplexers, a regenerative frequency divider (2:1), a dual output limiting amplifier, and two different types of mixers for clock extraction. Specifically, the design and performance of these IC's and a hybrid clock recovery module are discussed. The high performance and potential low cost of this research chipset show that advanced silicon bipolar circuit technology can play an important role in future multigigabit fiber-optic communication systems 相似文献
7.
8.
9.
10.
The scalar transform is a new representation for signals, offering a perspective that is different from the Fourier transform. We introduce the notion of a scalar periodic function. These functions are then represented through the discrete scale series. We also define the notion of a strictly scale-limited signal. Analogous to the Shannon interpolation formula, we show that such signals can be exactly reconstructed from exponentially spaced samples of the signal in the time domain. As an interesting, practical application, we show how properties unique to the scale transform make it very useful in computing depth maps of a scene 相似文献