全文获取类型
收费全文 | 102967篇 |
免费 | 6051篇 |
国内免费 | 1659篇 |
专业分类
电工技术 | 2490篇 |
技术理论 | 2篇 |
综合类 | 2632篇 |
化学工业 | 15945篇 |
金属工艺 | 2862篇 |
机械仪表 | 3288篇 |
建筑科学 | 3783篇 |
矿业工程 | 1133篇 |
能源动力 | 1960篇 |
轻工业 | 10385篇 |
水利工程 | 1476篇 |
石油天然气 | 1578篇 |
武器工业 | 205篇 |
无线电 | 6237篇 |
一般工业技术 | 12681篇 |
冶金工业 | 29384篇 |
原子能技术 | 702篇 |
自动化技术 | 13934篇 |
出版年
2024年 | 237篇 |
2023年 | 1017篇 |
2022年 | 1305篇 |
2021年 | 2063篇 |
2020年 | 1565篇 |
2019年 | 1655篇 |
2018年 | 2746篇 |
2017年 | 2887篇 |
2016年 | 3376篇 |
2015年 | 2924篇 |
2014年 | 3036篇 |
2013年 | 4664篇 |
2012年 | 5656篇 |
2011年 | 6094篇 |
2010年 | 3750篇 |
2009年 | 3620篇 |
2008年 | 3397篇 |
2007年 | 3289篇 |
2006年 | 2779篇 |
2005年 | 5190篇 |
2004年 | 4058篇 |
2003年 | 3578篇 |
2002年 | 2564篇 |
2001年 | 2193篇 |
2000年 | 1367篇 |
1999年 | 1670篇 |
1998年 | 8593篇 |
1997年 | 5578篇 |
1996年 | 3781篇 |
1995年 | 2334篇 |
1994年 | 1723篇 |
1993年 | 1783篇 |
1992年 | 592篇 |
1991年 | 621篇 |
1990年 | 531篇 |
1989年 | 492篇 |
1988年 | 517篇 |
1987年 | 418篇 |
1986年 | 369篇 |
1985年 | 351篇 |
1984年 | 236篇 |
1983年 | 208篇 |
1982年 | 299篇 |
1981年 | 350篇 |
1980年 | 388篇 |
1979年 | 185篇 |
1978年 | 215篇 |
1977年 | 911篇 |
1976年 | 1932篇 |
1975年 | 182篇 |
排序方式: 共有10000条查询结果,搜索用时 718 毫秒
121.
122.
123.
I. Budić-Leto T. Lovrić J. Gajdoš Kljusurić I. Pezo U. Vrhovšek 《European Food Research and Technology》2006,222(3-4):397-402
Identification of anthocyanins in the wine made of the Croatian autochthonous grape variety of Babić (Vitis vinifera L.) was carried out and their profile was determined by means of high-performance liquid chromatography with diode array
and mass spectrometric detection. Dependence of anthocyanins content and profile on maceration treatment conditions was investigated.
Statistically significant differences of anthocyanins concentration in wines Babić produced by various maceration treatments
were confirmed by the use of multivariate analysis of variances. The investigation results indicated that the maceration temperature
exerts higher influence on anthocyanins concentration than the duration of maceration. In addition, on the basis of anthocyanin
composition and using different multivariate statistical analyses, differentiation of wines Babić according to maceration
treatments was procured. 相似文献
124.
125.
Rossato Janine I.; Bonini Juliana S.; Coitinho Adriana S.; Vianna Monica R. M.; Medina Jorge H.; Cammarota Martín; Izquierdo Iván 《Canadian Metallurgical Quarterly》2004,118(3):563
The gamma aminobutyric acid-A (GABAA) agonist, muscimol, the glutamate N-methyl-D-aspartate (NMDA) receptor antagonist, D-2-amino-5-phosphonopentanoic acid (AP5), and the inhibitor of the extracellularly regulated kinases (ERKs), UO 126, cause retrograde amnesia when administered to the hippocampus. In the present study, the authors found that they all cause retrograde amnesia for 1-trial inhibitory avoidance, not only when infused into the dorsal CA1 region of the hippocampus, but also when infused into the basolateral amygdala or the entorhinal, parietal, and posterior cingulate cortices. The posttraining time course of the effect of each drug was, however, quite different across brain structures. Thus, in all of them, NMDA receptors and the ERK pathway are indispensable for memory consolidation, and GABAA receptor activation inhibits memory consolidation: but in each case, their influence is interwoven differently. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
126.
127.
金属/Al2O3基纳米复合材料研究最新进展 总被引:2,自引:0,他引:2
金属/Al2O3纳米复合材料在保持原有金属的功能特性时,还可以获得 很好的力学性能,是有良好发展前景的一种纳米复合材料。本文回顾了近年来金属/Al2O3基纳米复合材料在制备工艺,微观结构和力学性能,增韧强化机理方面的最新进展,并指出了今后的研究方向。 相似文献
128.
The expression of cytokeratins (CK), involucrin, vimentin, CD34, and alpha-smooth-muscle actin was studied in fetal and adult hair follicles. The first stage of the developing hair follicle is characterized by palisaded, elongated epithelial cells budding from the epidermal basal layer. These cells express CK5/6, CK14, CK17, CK19, and vimentin. During the following weeks of gestation, different structures in the developing hair follicle can be identified and characterized. The matrical cells display only CK19. The keratinocytes of the outer root sheath express CK5/6, CK14, CK17, CK19, and involucrin; those of the inner root sheath, CK4, CK18, and involucrin; those of the isthmus, the same profile as the ORS. In the infundibulum, the basal-layer keratinocytes express CK5/6, CK14, CK17, and CK19, whereas in the suprabasal layers CK1, CK4, CK10, CK14, and CK17 are seen. The adult hair follicle in anagen fails to express CK19 in the matrical cells and isthmus and both CK17 and CK19 in the infundibulum. These profiles of intermediate filaments and other markers appear to be potentially useful in categorizing neoplasms with apparent follicular differentiation. 相似文献
129.
130.
Phospholamban (PLN) was expressed in Escherichia coli as a protein fusion with glutathione S-transferase (GST). GST-PLN was mostly present in the insoluble protein fraction and accounted for approximately 50% of total insoluble protein. Attempts to suppress inclusion body formation or to use GST as an affinity-purification tag failed. A successful purification method is based on preparative SDS/PAGE and electrodialysis. From 1 g cells we typically purified 13.5 mg fusion protein with a PLN content of 2.8 mg. We genetically inserted an enterokinase (EK) protease site just in front of the PLN sequence and demonstrated the proteolytical liberation of PLN from the carrier protein. The approach described represents a substantial advancement in PLN expression and purification. 相似文献