无微不至 (wú wēi bù zhì)

in every possible way (idiom); meticulous

Character breakdown

无 (mó) · 4 strokes

Pictograph of a person dancing, with ox tails or bird feathers hanging from his arms, to pray for rain. Original form of 舞 (dance). The current form is a phonetic loan. The simplified character 无 was…
微 (Wēi) · 13 strokes

Phonosemantic compound. 彳 represents the meaning and 𢼸 represents the sound. Based on the original meaning "go out and hide". The meaning later shifted to "conceal" and "tiny".
不 (bù) · 4 strokes

Pictograph of sepals of a flower. The modern meaning "no" is a phonetic loan.
至 (zhì) · 6 strokes

Pictograph of an arrow hitting its target.

老师对学生无微不至地关怀。
in every possible way (idiom); meticulous
lǎo shī duì xué shēng wú wēi bù zhì dì guān huái 。