全文获取类型
收费全文 | 199680篇 |
免费 | 12412篇 |
国内免费 | 6319篇 |
专业分类
电工技术 | 9288篇 |
技术理论 | 7篇 |
综合类 | 10202篇 |
化学工业 | 30158篇 |
金属工艺 | 11247篇 |
机械仪表 | 10732篇 |
建筑科学 | 11039篇 |
矿业工程 | 4514篇 |
能源动力 | 4650篇 |
轻工业 | 11597篇 |
水利工程 | 3510篇 |
石油天然气 | 7713篇 |
武器工业 | 1092篇 |
无线电 | 22381篇 |
一般工业技术 | 30110篇 |
冶金工业 | 7987篇 |
原子能技术 | 1450篇 |
自动化技术 | 40734篇 |
出版年
2024年 | 530篇 |
2023年 | 2380篇 |
2022年 | 4301篇 |
2021年 | 6178篇 |
2020年 | 4386篇 |
2019年 | 3578篇 |
2018年 | 17782篇 |
2017年 | 17226篇 |
2016年 | 13346篇 |
2015年 | 5564篇 |
2014年 | 6391篇 |
2013年 | 7513篇 |
2012年 | 11046篇 |
2011年 | 17729篇 |
2010年 | 15469篇 |
2009年 | 12354篇 |
2008年 | 13376篇 |
2007年 | 13963篇 |
2006年 | 6225篇 |
2005年 | 6682篇 |
2004年 | 4667篇 |
2003年 | 4212篇 |
2002年 | 3282篇 |
2001年 | 2494篇 |
2000年 | 2644篇 |
1999年 | 2663篇 |
1998年 | 2184篇 |
1997年 | 1744篇 |
1996年 | 1723篇 |
1995年 | 1414篇 |
1994年 | 1144篇 |
1993年 | 832篇 |
1992年 | 644篇 |
1991年 | 518篇 |
1990年 | 376篇 |
1989年 | 290篇 |
1988年 | 260篇 |
1987年 | 161篇 |
1986年 | 132篇 |
1985年 | 99篇 |
1984年 | 65篇 |
1982年 | 53篇 |
1968年 | 46篇 |
1966年 | 42篇 |
1965年 | 45篇 |
1959年 | 42篇 |
1958年 | 37篇 |
1957年 | 36篇 |
1955年 | 63篇 |
1954年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Breast cancer is the most frequently diagnosed cancer in women worldwide. The disease and its treatments exert profound effects on an individual’s physical and mental health. There are many factors that impact an individual’s risk of developing breast cancer, their response to treatments, and their risk of recurrence. The community of microorganisms inhabiting the gastrointestinal tract, the gut microbiota, affects human health through metabolic, neural, and endocrine signaling, and immune activity. It is through these mechanisms that the gut microbiota appears to influence breast cancer risk, response to treatment, and recurrence. A disrupted gut microbiota or state of ‘dysbiosis’ can contribute to a biological environment associated with higher risk for cancer development as well as contribute to negative treatment side-effects. Many cancer treatments have been shown to shift the gut microbiota toward dysbiosis; however, the microbiota can also be positively manipulated through diet, prebiotic and probiotic supplementation, and exercise. The objective of this review is to provide an overview of the current understanding of the relationship between the gut microbiota and breast cancer and to highlight potential strategies for modulation of the gut microbiota that could lead to improved clinical outcomes and overall health in this population. 相似文献
82.
83.
84.
Correlation between instrumental texture and colour quality attributes with sensory analysis of selected cheeses as affected by fat contents
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A. Półtorak J. Wyrwisz M. Moczkowska M. Marcinkowska‐Lesiak A. Stelmasiak U. Ulanicka M. Zalewska A. Wierzbicka Da‐Wen Sun 《International Journal of Food Science & Technology》2015,50(4):999-1008
This study evaluated several physical and sensory parameters of different types of cheese available in the Polish market. The measurements of textural properties were conducted in an Instron universal testing machine, while the colour properties of cheeses were measured using a Minolta chromameter. The chemical composition was determined by means of the near‐infrared spectroscopy (NIRs). Moreover, a trained sensory panel was invited to assess the cheese texture‐related properties. Generally, cheeses with reduced fat content were characterised by higher hardness, adhesiveness, cohesiveness and elasticity. Texture‐related parameters of cheese with canola oil were comparable to that of most of full‐fat cheeses. The correlation analysis between physical and sensory attributes related to cheese textural properties indicated the potential applications of TPA, shear and penetration tests (r = 0.766, r = 0.75 and r = 0.765, respectively) for the evaluation of sensory properties related to the hardness. Meanwhile, the elasticity of cheese obtained from sensory evaluation was strongly correlated with the elasticity determined from the shear test (r = 0.722) and moderately correlated with the elasticity from penetration test (r = 0.588), indicating a need to refine the method of penetration test. In addition, cheeses exhibited higher meltability during convection heating at 230 °C than microwave heating. The values of meltability for cheese with reduced fat content were lower than those of full‐fat cheese. 相似文献
85.
Variations of Incomplete Open Cubes is the major project by the twentieth-century conceptual artist Sol LeWitt. In this paper we interpret the enumerative component of the project as embeddings of graphs. This formulation permits use of an algorithm to check the completeness of the list of the structures produced by the artist. Our conclusion is that the artist found the correct number of structures (that is, 122), but that his list contains a mistake in the presentation of a pair of incomplete cubes, a discovery that appears not to have been noted before. 相似文献
86.
87.
We propose an analytical model to evaluate the lightpath blocking performance for a single ROADM node with intra-node add/drop contention,in which the number of lightpaths that can be added/dropped with the same wavelength is limited by the add/drop contention factor.Different models of traffic load per nodal degree are considered to validate the effectiveness of the analytical model.The simulation results show that the proposed analytical model is effective in predicting the performance for different values of add/drop contention factor C and for variable offered loads at the node.The add/drop contention factor shows an important impact on the lightpath blocking performance and properly raising the contention factor can significantly improve the lightpath blocking performance.When the add/drop contention factor C exceeds a certain level,the performance of a ROADM with intra-node contention is close to that of a contentionless ROADM. 相似文献
88.
Neural Processing Letters - The beta processes (BP) is a powerful nonparametric tool in feature learning, which is often used as the prior of Bernoulli process for choosing features from a feature... 相似文献
89.
90.