全文获取类型
收费全文 | 5743篇 |
免费 | 117篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 56篇 |
综合类 | 2篇 |
化学工业 | 748篇 |
金属工艺 | 120篇 |
机械仪表 | 66篇 |
建筑科学 | 176篇 |
矿业工程 | 29篇 |
能源动力 | 52篇 |
轻工业 | 337篇 |
水利工程 | 22篇 |
石油天然气 | 8篇 |
无线电 | 298篇 |
一般工业技术 | 518篇 |
冶金工业 | 3039篇 |
原子能技术 | 39篇 |
自动化技术 | 352篇 |
出版年
2022年 | 20篇 |
2021年 | 45篇 |
2020年 | 53篇 |
2019年 | 45篇 |
2018年 | 60篇 |
2017年 | 42篇 |
2016年 | 68篇 |
2015年 | 57篇 |
2014年 | 79篇 |
2013年 | 87篇 |
2012年 | 115篇 |
2011年 | 137篇 |
2010年 | 114篇 |
2009年 | 109篇 |
2008年 | 116篇 |
2007年 | 113篇 |
2006年 | 102篇 |
2005年 | 126篇 |
2004年 | 79篇 |
2003年 | 84篇 |
2002年 | 83篇 |
2001年 | 88篇 |
2000年 | 83篇 |
1999年 | 136篇 |
1998年 | 922篇 |
1997年 | 541篇 |
1996年 | 345篇 |
1995年 | 265篇 |
1994年 | 193篇 |
1993年 | 222篇 |
1992年 | 75篇 |
1991年 | 86篇 |
1990年 | 82篇 |
1989年 | 78篇 |
1988年 | 61篇 |
1987年 | 56篇 |
1986年 | 58篇 |
1985年 | 66篇 |
1984年 | 31篇 |
1983年 | 33篇 |
1982年 | 46篇 |
1981年 | 51篇 |
1980年 | 51篇 |
1979年 | 50篇 |
1978年 | 25篇 |
1977年 | 93篇 |
1976年 | 172篇 |
1975年 | 24篇 |
1974年 | 18篇 |
1972年 | 18篇 |
排序方式: 共有5862条查询结果,搜索用时 359 毫秒
1.
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
2.
Daniel Biedermann Jan Schneider Hendrik Drachsler 《Journal of Computer Assisted Learning》2021,37(5):1217-1231
Digital distractions can interfere with goal attainment and lead to undesirable habits that are hard to get red rid of. Various digital self-control interventions promise support to alleviate the negative impact of digital distractions. These interventions use different approaches, such as the blocking of apps and websites, goal setting, or visualizations of device usage statistics. While many apps and browser extensions make use of these features, little is known about their effectiveness. This systematic review synthesizes the current research to provide insights into the effectiveness of the different kinds of interventions. From a search of the ‘ACM’, ‘Springer Link’, ‘Web of Science’, ’IEEE Xplore’ and ‘Pubmed’ databases, we identified 28 digital self-control interventions. We categorized these interventions according to their features and their outcomes. The interventions showed varying degrees of effectiveness, and especially interventions that relied purely on increasing the participants' awareness were barely effective. For those interventions that sanctioned the use of distractions, the current literature indicates that the sanctions have to be sufficiently difficult to overcome, as they will otherwise be quickly dismissed. The overall confidence in the results is low, with small sample sizes, short study duration, and unclear study contexts. From these insights, we highlight research gaps and close with suggestions for future research. 相似文献
3.
4.
MB Heyman JM LaBerge KA Somberg P Rosenthal C Mudge EJ Ring JD Snyder 《Canadian Metallurgical Quarterly》1997,131(6):914-919
The transjugular intrahepatic portosystemic shunt procedure is an accepted treatment for adults with complications of portal hypertension. We performed a retrospective review of all pediatric TIPS placements performed at the University of California, San Francisco between 1990 and 1996. Twelve procedures were attempted in nine children, with a mean age (+/- SD) of 9.4 +/- 3.9 years (range, 5 to 15 years) and a mean weight of 31 +/- 18 kg (range, 16 to 70 kg). The indications for TIPS placement were portal hypertension complicated by chronic variceal hemorrhage not controlled with sclerotherapy (n = 7) and hypersplenism with thrombocytopenia (n = 2). TIPS placement was successfully completed initially in seven of nine (78%) patients. Unfavorable vascular anatomy was the cause of failure in two cases. The seven patients who underwent successful TIPS placement were followed up for an average of 136 days (range, 1 to 800 days); two still have patent shunts, three underwent liver transplantation, one had a splenorenal shunt after stenosis, and one died of underlying liver disease. Variceal bleeding was controlled in four of five patients who successfully underwent TIPS placement. Shunt occlusion occurred in four patients; patency was restored by transjugular shunt revision in three, and a splenorenal shunt was performed in one. 相似文献
5.
Butyl, hexyl, and 2-ethylhexyl diesters of 1,1-bis(5-carboxyl-2-furyl)-2,2-dichloroethene, hexyl and 2-ethylhexyl diesters of 1,1-bis(5-carboxyl-2-furyl) ketone, and the hexyl diester of 1,1-bis(5-carboxyl-2-furyl)methane were synthesized from furfural and evaluated for their plasticizing abilities toward PVC, by the application of dynamic mechanical thermal analysis and [di(2-ethylhexyl) phthalate] as a standard of reference. © 1995 John Wiley & Sons, Inc. 相似文献
6.
7.
IS Grewal P Borrow EG Pamer MB Oldstone RA Flavell 《Canadian Metallurgical Quarterly》1997,9(4):491-497
Research in the past few years has documented significant advances in our understanding of the CD40-CD40 ligand (CD154) system in diverse immune functions. This system influences many T cell mediated inflammatory immune responses and effector functions, unmasking a previously unexpected role for CD40-CD154 in cell mediated immunity. Manipulation of CD154 in animal models of infection by the use of CD154-deficient mice or anti-CD154 antibodies has shown the importance of this system in the initiation of the inflammatory response, in the activation of antigen-presenting cells and in resistance to infections. 相似文献
8.
T Reck F K?ckerling C Schneider W Hohenberger 《Canadian Metallurgical Quarterly》1997,122(10):914-918
Morgagni hernias are the least common form of diaphragmatic hernias. Although they are congenital, most of them are not diagnosed until later in life. The indication for surgery is based on the patient's symptoms or on the radiological evidence of incarcerated tissue, and until quite recently involved a laparotomy or thoracotomy. Laparoscopy not only permits the suspected diagnosis to be confirmed--which is otherwise often difficult--but also makes it possible to close the hernia site by suturing. For improved security, the hernia site is augmented by fixing in place a non-absorbable mesh. The operative technique employed is described. 相似文献
9.
Robotica is a computer-aided design package for robotic nmanipulators developed at the Coordinated Science Laboratory at the University of Illinois at Urbana- Champaign. The package is a collection of function definitions for the Mathematica symbolic mathematics program. Robotica can be used either with an X- Windows graphical user interface (GUI) on a Sun Workstation or as an included function definition file within Mathematica. The primary feature of Robotica is the ability to compute, symbolically or numerically, the kinematic and dynamic equations of arbitrary robot systems utilizing the standard Denevit-Hartenburg (DH) kinematic convention. Robotica also provides the ability to visualize these arbitrary manipulators using the X- Windows graphical interface to the Mathematica graphics routines. The paper looks at the usage of Robotica at the Air Force Institute of Technology, comments on the features of Robotica, and needs for improvement and suggestions for future development 相似文献
10.
MG McInnis A Chakravarti J Blaschak MB Petersen V Sharma D Avramopoulos JL Blouin U K?nig C Brahe TC Matise 《Canadian Metallurgical Quarterly》1993,16(3):562-571
A genetic linkage map of human chromosome 21q (HC21q) containing 43 markers genotyped by the polymerase chain reaction in the CEPH pedigrees is presented. The markers placed on this map are highly polymorphic with an average heterozygosity of 61%. The average interval size of the markers localized at 1000:1 odds is 2.5 cM. The map has a total length of 65.5 cM, with male and female lengths of 47.7 and 83.3 cM, respectively. The genotypes used in the construction of this map were subjected to rigorous error checking, which is reflected in the shorter map length compared to previous maps; the estimated error rate in genotyping is less than 0.04%. As noted in previous linkage maps there is increased recombination in females on proximal HC 21q and in the male in a region near the telomere. This map of HC 21 represents a highly informative and dense meiotic linkage map and will be useful in linking disease phenotypes to loci on this chromosome. 相似文献