全文获取类型
收费全文 | 10286篇 |
免费 | 828篇 |
国内免费 | 466篇 |
专业分类
电工技术 | 61篇 |
技术理论 | 1篇 |
综合类 | 678篇 |
化学工业 | 2038篇 |
金属工艺 | 430篇 |
机械仪表 | 195篇 |
建筑科学 | 527篇 |
矿业工程 | 309篇 |
能源动力 | 384篇 |
轻工业 | 3988篇 |
水利工程 | 392篇 |
石油天然气 | 642篇 |
武器工业 | 26篇 |
无线电 | 241篇 |
一般工业技术 | 748篇 |
冶金工业 | 476篇 |
原子能技术 | 212篇 |
自动化技术 | 232篇 |
出版年
2024年 | 57篇 |
2023年 | 150篇 |
2022年 | 271篇 |
2021年 | 313篇 |
2020年 | 344篇 |
2019年 | 320篇 |
2018年 | 312篇 |
2017年 | 361篇 |
2016年 | 427篇 |
2015年 | 378篇 |
2014年 | 579篇 |
2013年 | 609篇 |
2012年 | 754篇 |
2011年 | 791篇 |
2010年 | 493篇 |
2009年 | 535篇 |
2008年 | 461篇 |
2007年 | 625篇 |
2006年 | 549篇 |
2005年 | 456篇 |
2004年 | 394篇 |
2003年 | 351篇 |
2002年 | 335篇 |
2001年 | 228篇 |
2000年 | 216篇 |
1999年 | 204篇 |
1998年 | 163篇 |
1997年 | 132篇 |
1996年 | 110篇 |
1995年 | 129篇 |
1994年 | 75篇 |
1993年 | 87篇 |
1992年 | 81篇 |
1991年 | 51篇 |
1990年 | 45篇 |
1989年 | 36篇 |
1988年 | 30篇 |
1987年 | 21篇 |
1986年 | 18篇 |
1985年 | 22篇 |
1984年 | 18篇 |
1983年 | 13篇 |
1982年 | 11篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1977年 | 1篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Effect of complexation of oxidised corn starch with mineral elements on physicochemical properties 下载免费PDF全文
Sławomir Pietrzyk Teresa Fortuna Lesław Juszczak Dorota Gałkowska Karolina Królikowska Karolina Zięba 《International Journal of Food Science & Technology》2015,50(4):934-941
The objective of this study was to determine the effect of complexation of oxidised starch with mineral elements on its physicochemical properties. Corn starch was oxidised with sodium hypochlorite and, afterwards, modified with ions of potassium, magnesium and iron. Thus, native and modified starches were analysed for: contents of mineral elements, colour parameters (L*a*b*), water binding capacity and solubility in water at temperature of 60 and 80 °C. Thermodynamic characteristics of gelatinisation by DSC, molecular weight distribution by GPC, intrinsic viscosity and pasting properties by RVA were studied. The efficiency of incorporation of metal ions into oxidised corn starch was about 30%, 20% and 20% for potassium, magnesium and iron ions, respectively. The complexation with potassium ions caused the greatest changes in the molecular weight distribution and the intrinsic viscosity of starches and viscosity of starch pastes. Only modification of starch with iron ions affected the colour parameters of the starch. Incorporation of metal ions into starch resulted also in changes in its water binding capacity and solubility in water. 相似文献
2.
The aim of this paper is to assess the closeness of agreement between results of ELISA and LC-MS/MS methods for determination of aflatoxin B1 in corn and aflatoxin M1 in milk. Samples of corn (n=100) and milk (n=250) were simultaneously analyzed using ELISA and LC-MS/MS methods, after the severe drought that affected Serbia in summer 2012 resulting in occurrence of aflatoxin B1 in corn and aflatoxin M1 in milk. Regression analysis showed higher level of agreement between aflatoxin B1 samples (R2=0.994), compared to aflatoxin M1 samples (R2=0.920). However, both techniques were satisfactory in meeting the requirements for official control purposes. 相似文献
3.
This paper reports the results of an investigation of a set of continuous time, constant demand inventory models under the condition of yield uncertainty. Specifically, the impact of yield improvement programs on lot size, backorder level, and the resulting costs are examined. Models for improving yield rate and reducing yield variability are developed and examined through a series of numerical exercises. In addition, a model for the simultaneous improvement of yield rate and yield variability is presented for the case where there is a relationship between the mean and variance of the yield distribution. In all cases, investment programs improve the picture with respect to manufacturing yield for processes which are not necessarily under statistical control. 相似文献
4.
The tensile elastic modulus (E), yield stress (σY) and microhardness (MH) of neat and binary and ternary blends of glassy semicrystalline ethylene–vinyl alcohol copolymer (EVOH), a glassy amorphous polyamide and a semicrystalline nylon‐containing ionomer covering a broad range of properties were examined. The tests were carried out on dry and water‐equilibrated samples to produce stiffer and softer materials, respectively. From the results, more accurate linear correlations were found to describe adequately the microhardness, modulus and yield stress of these strongly self‐associated polymers through hydrogen bonding. Copyright © 2003 Society of Chemical Industry 相似文献
5.
6.
介绍了利用现有的催化裂化装置 ,通过优化操作及运用MGD技术提高柴油和液化气收率的方法和技术措施。 相似文献
7.
Although the literature on the mechanics of cellular materials is vast, there is no theoretical model to account for the effects of axial yielding of struts aligned to the applied loading direction on the plastic yield surface under multiaxial loading conditions. An anisotropic hexagonal model having tapered strut morphology is developed to show these effects on the plastic yield surface under multiaxial tensile loading condition. This model covers several types of cellular structure such as two-dimensional (2D) hexagonal and square cellular materials, and three-dimensional (3D) hexagonal and rhombic cellular materials of rod-like columnar structure. A tetrahedral element with tapered strut morphology is also used for a foam model to illustrate these effects on the yield surface under axisymmetric loading condition. Plastic collapse due to bending moment in the inclined struts is a dominant mode. However, under multiaxial tensile loading, the collapse due to axial yielding of struts parallel to the loading direction is found to be an important mode. The shape of plastic yield surface was found to depend not only on relative density but also on the strut morphology. 相似文献
8.
9.
10.
恰当选择原材料、确保铆接工序质量、重视工作电解液的配比、严控各工序成品率是提高超小型铝电解电容器投入产出一次合格率的关键。以10V-47μF(4mm×7mm)产品为例,投入产出一次合格率达94%以上。 相似文献