Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
cua triet » cua viet, su triet, va triet
cam thuc » am thuc, nam thuc, cam thu
thu sach » tu sach, thuoc sach, thu hoach
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
ve cam » ve cham, ve cac, va cam
va cua » va chua, via cua, ca cua

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) or (thuat sach)) ky ((nang x) or (nang ma)) hoi. hieu ve cam thuc va hanh va cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuat sach)) ky ((nang x) OR (nang ma)) hoi. hieu ve cam thuc va hanh va cua triet.
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thuat sach)) ky ((nang x) or (nang ma)) hoi. hieu ve cam thuc va hanh va cua triet*.