Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
trinh vi » trinh va, trinh ve, trinh viet
phan duc » pham duc, phan tu, phan dau
cau tren » cu tren, dau tren, ca tren
lang ra » lang ha, lang xa, lang va
sach vu » sach va, sach tu, sach uu
nang ra » nang ma, nang ro, nang va
tinh vi » tinh voi, tinh va, dinh vi
va phan » van phan, va phat, va phap

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach vu ((nang ra) OR (lang ra)) khoi. lieu va phan duc va ((tinh vi) or (trinh vi)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach vu ((nang ra) OR (lang ra)) khoi. lieu va phan duc va ((tinh vi) OR (trinh vi)) cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach vu ((nang ra) OR (lang ra)) khoi. lieu va phan duc va ((tinh vi) or (trinh vi)) cau tren".
• Adding a wildcard symbol may retrieve word variants: thuoc sach vu ((nang ra) OR (lang ra)) khoi. lieu va phan duc va ((tinh vi) or (trinh vi)) cau tren*.