Perhaps you should try some spelling variations:
su sach » so sach, vu sach
va danh » va dinh, va hanh, dia danh
cam duc » cam xuc, cao duc, pham duc
hieu ve » hieu va, hieu van
cuu tre » cua tre, cau tren, cau treo
nang ma » tang ma, sang ma, nang cao
va dan » ca dan, va dao, va dau
vi cuu » vi luu, vinh cuu
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y ((nang x) or (nang ma)) hoi. hieu ve cam duc ((va danh) OR (va dan)) vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang x) OR (nang ma)) hoi. hieu ve cam duc ((va danh) OR (va dan)) vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang x) or (nang ma)) hoi. hieu ve cam duc ((va danh) OR (va dan)) vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang x) or (nang ma)) hoi. hieu ve cam duc ((va danh) OR (va dan)) vi cuu tre*.