全文获取类型
收费全文 | 6556篇 |
免费 | 62篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 47篇 |
化学工业 | 398篇 |
金属工艺 | 71篇 |
机械仪表 | 58篇 |
建筑科学 | 125篇 |
矿业工程 | 15篇 |
能源动力 | 42篇 |
轻工业 | 301篇 |
水利工程 | 30篇 |
石油天然气 | 8篇 |
无线电 | 296篇 |
一般工业技术 | 460篇 |
冶金工业 | 4353篇 |
原子能技术 | 20篇 |
自动化技术 | 399篇 |
出版年
2021年 | 29篇 |
2019年 | 20篇 |
2018年 | 26篇 |
2017年 | 32篇 |
2016年 | 17篇 |
2015年 | 34篇 |
2014年 | 58篇 |
2013年 | 151篇 |
2012年 | 103篇 |
2011年 | 103篇 |
2010年 | 58篇 |
2009年 | 61篇 |
2008年 | 91篇 |
2007年 | 109篇 |
2006年 | 105篇 |
2005年 | 77篇 |
2004年 | 83篇 |
2003年 | 90篇 |
2002年 | 77篇 |
2001年 | 57篇 |
2000年 | 56篇 |
1999年 | 202篇 |
1998年 | 1363篇 |
1997年 | 810篇 |
1996年 | 515篇 |
1995年 | 280篇 |
1994年 | 259篇 |
1993年 | 280篇 |
1992年 | 77篇 |
1991年 | 61篇 |
1990年 | 70篇 |
1989年 | 72篇 |
1988年 | 78篇 |
1987年 | 58篇 |
1986年 | 53篇 |
1985年 | 69篇 |
1984年 | 29篇 |
1983年 | 28篇 |
1982年 | 45篇 |
1981年 | 60篇 |
1980年 | 58篇 |
1979年 | 28篇 |
1978年 | 35篇 |
1977年 | 143篇 |
1976年 | 227篇 |
1975年 | 31篇 |
1974年 | 23篇 |
1973年 | 29篇 |
1972年 | 19篇 |
1971年 | 18篇 |
排序方式: 共有6623条查询结果,搜索用时 15 毫秒
1.
Zenan Yu Julian Moore Jean Calderon Lei Zhai Jayan Thomas 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(39):5289-5295
Cable‐shaped supercapacitors (SCs) have recently aroused significant attention due to their attractive properties such as small size, lightweight, and bendability. Current cable‐shaped SCs have symmetric device configuration. However, if an asymmetric design is used in cable‐shaped supercapacitors, they would become more attractive due to broader cell operation voltages, which results in higher energy densities. Here, a novel coil‐type asymmetric supercapacitor electrical cable (CASEC) is reported with enhanced cell operation voltage and extraordinary mechanical‐electrochemical stability. The CASECs show excellent charge–discharge profiles, extraordinary rate capability (95.4%), high energy density (0.85 mWh cm−3), remarkable flexibility and bendability, and superior bending cycle stability (≈93.0% after 4000 cycles at different bending states). In addition, the CASECs not only exhibit the capability to store energy but also to transmit electricity simultaneously and independently. The integrated electrical conduction and storage capability of CASECS offer many potential applications in solar energy storage and electronic gadgets. 相似文献
2.
3.
Math1 is essential for genesis of cerebellar granule neurons 总被引:1,自引:0,他引:1
N Ben-Arie HJ Bellen DL Armstrong AE McCall PR Gordadze Q Guo MM Matzuk HY Zoghbi 《Canadian Metallurgical Quarterly》1997,390(6656):169-172
4.
5.
6.
MM Koerner G Tenderich K Minami M Morshuis N Mirow L Arusoglu H Gromzik S Wlost R Koerfer 《Canadian Metallurgical Quarterly》1997,63(9):1358-1360
BACKGROUND: An increasing demand for cardiac allografts for the treatment of end-stage cardiac failure has led to a shift in the traditional views about donor criteria. The use of allografts exposed to high concentrations of carbon monoxide is still under discussion. The current literature on this topic is contradictory. We describe our experience with orthotopic cardiac transplantation, using cardiac allografts after carbon monoxide poisoning. METHODS: Between March 13, 1989 and August 1, 1996, 770 orthotopic heart transplantations were performed in our center. Within this period, we accepted five cardiac allografts from brain-dead, carbon monoxide-poisoned donors. Donor history showed carbon monoxide intoxication in all cases. At the time of organ explantation, donor hemodynamic parameters were feeble in all patients. RESULTS: The postoperative course was uneventful in three of the five recipients. The overall 3-year survival rate in this small group is 40%. Induction therapy or rescue therapy with mono/polyclonal antibodies was not necessary. Myocardial right-ventricular biopsies did not show any specific signs of carbon monoxide poisoning. CONCLUSIONS: In our opinion, cardiac allografts from donors exposed to carbon monoxide can be transplanted successfully in infants and adults, if there are no signs of severe hemodynamic dysfunction in the presence of a normal central venous pressure and low-dose support with catecholamines and there are no electrocardiographic changes in combination with elevated transaminase. With extended donor criteria, the hearts of carbon monoxide-poisoned victims could increase the number of suitable organs and lower the death rate of patients on the United Network for Organ Sharing and Eurotransplant International Foundation waiting lists. 相似文献
7.
NC Moore 《Canadian Metallurgical Quarterly》1997,86(2):81-82
The nation's health care system is undergoing a period of rapid change that will profoundly affect women's health care services and, ultimately, women's health. Although managed care is quickly becoming the predominant mode of health care delivery in the United States, a new, more consumer-focused, and accountable model known as organized systems of care (OSC) is emerging. OSC development has been driven by large private and public employers seeking to purchase the highest quality health care for the best price. The changes in health care delivery encouraged by these innovative employers will provide women with optimal care and attention, which will in turn help them attract and retain a competitive and productive workforce. 相似文献
8.
9.
The purpose of this study was to identify the optimal knot construction for interrupted dermal sutures. A synthetic braided absorbable suture, sizes 3-0 and 5-0, was selected for this evaluation. With reproducible mechanical performance tests, we determined that the construction of secure knots without ears required one additional throw as compared with secure knots with 3-mm ears. The direction of applied tension did not alter knot security, with the exception of granny knots, which required an extra throw when tension was applied parallel to the suture loop. Because interrupted dermal knot construction is accomplished without knot ears and with an applied tension parallel to the wound, one additional throw must be added to the knot to ensure knot security. 相似文献
10.