Perhaps you should try some spelling variations:
sang mai » sang ma, lang mai, hoang mai
sang tai » hang tai, sang tao, tang tai
so sach » so sanh, bo sach, co sach
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
le dat » de dat, le dac, ve dat
le dan » ke dan
vi cuu » vi luu, vinh cuu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach _ ((sang mai) OR (sang tai)) hoi. hieu ((le dat) or (le dan)) nuoc va hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach _ ((sang mai) OR (sang tai)) hoi. hieu ((le dat) OR (le dan)) nuoc va hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach _ ((sang mai) OR (sang tai)) hoi. hieu ((le dat) or (le dan)) nuoc va hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: so sach _ ((sang mai) OR (sang tai)) hoi. hieu ((le dat) or (le dan)) nuoc va hanh vi cuu tre*.