Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
nang ma » tang ma, sang ma, nang cao
lieu ca » lieu cao, lieu va, lieu ma
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
la tren » loai tren, dua tren, dat tren
va la » va lap, va lam, va lai

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y ((nang ma) or (mang may)) hoi. lieu ca ((nhan luc) OR (nang luc)) va hanh va la tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y ((nang ma) OR (mang may)) hoi. lieu ca ((nhan luc) OR (nang luc)) va hanh va la tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y ((nang ma) or (mang may)) hoi. lieu ca ((nhan luc) OR (nang luc)) va hanh va la tren".
• Adding a wildcard symbol may retrieve word variants: thu sach y ((nang ma) or (mang may)) hoi. lieu ca ((nhan luc) OR (nang luc)) va hanh va la tren*.