by heart

基本解释

This would mean diets with less saturated fat and fewer premature deaths caused by heart disease, they write.
他们指出这样就降低了饮食中的饱和脂肪酸和由心脏疾病导致的婴幼儿夭折。
In several studies, this test alerted doctors to over 90 percent of people with atrial fibrillation, as confirmed by heart monitoring.
在几项研究中，经心脏监测证实，这个测试让医生注意到，超过90%的人患有房颤。
Most of us in this country--all who were raised here--know the words and music of our National Anthem by heart.
我们国家里大部分的人，和在这个国家长大的人，对于这首国歌的曲调和歌词都已烂熟于心。

For example, your body reacts to stressful situations by raising your blood pressure and making your heart work harder.
Second thing, we started talking about the periodic table and I believe that it's a hallmark of any educated person in the 21st century who is technically literate to know the periodic table by heart.
第二点，我们之前讨论过元素周期表,我相信这是个标志性的特征,对于那些在21世纪里,用心去学习,元素周期表的人来说。
麻省理工公开课 - 固态化学导论课程节选
But in your heart you know it can't be done by today.
但你心里清楚今天是不可能做完的。
I don't know 课堂 - SpeakingMax英语口语达人

The songs I knew by heart penetrated me as I sat there trying to deafen myself.
NEWYORKER: Mr. Bones