尽管 (jǐnguǎn)…但是/还是 is a beefed-up 虽然: 尽管工作很忙,她还是每天学中文 "even though work is busy, she still studies Chinese every day". Same structure as 虽然, stronger concession, and a touch more written.
Bonus meaning: before a verb in a friendly offer, 尽管 means "go right ahead": 有问题尽管问 "if you have questions, just ask away". And keep it apart from 不管 — 不管 needs a question form after it ("no matter what"), while 尽管 takes a plain fact ("although this is true").
Examples
尽管天气不好,他还是去跑步了。
儘管天氣不好,他還是去跑步了。
jǐn guǎn tiān qì bù hǎo tā hái shi qù pǎo bù le
Although the weather was bad, he still went running.
尽管工作很忙,她还是每天学中文。
儘管工作很忙,她還是每天學中文。
jǐn guǎn gōng zuò hěn máng tā hái shi měi tiān xué zhōng wén
Even though work is busy, she still studies Chinese every day.
尽管我说了很多次,但是他还是不听。
儘管我說了很多次,但是他還是不聽。
jǐn guǎn wǒ shuō le hěn duō cì dàn shì tā hái shi bù tīng
Although I've said it many times, he still won't listen.
你有什么问题,尽管问。
你有什麼問題,儘管問。
nǐ yǒu shén me wèn tí jǐn guǎn wèn
Whatever questions you have, feel free to ask.
Common mistakes
✗ 尽管天气怎么样,我都去。
✓ 不管天气怎么样,我都去。
A question form after the connector means "no matter" — that's 不管; 尽管 concedes a real fact.
Every grammar point in this guide is built into the Literate Chinese app, with graded stories that use the pattern naturally and flashcards matched to the words you know — in Mainland or Taiwan Mandarin. Free on iOS and Android.