Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
hien bach » vien bach, hien hanh, dien sach
sach thu » sach thue, sach thieu, sach tham
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
bo sach » co sach, hoc sach
nang ma » tang ma, sang ma, nang cao
vi cua » vai cua, di cua
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach thu ((nang ma) or (nang x)) hoi. hieu ((hien bach) OR (thien hach)) nuoc va danh vi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach thu ((nang ma) OR (nang x)) hoi. hieu ((hien bach) OR (thien hach)) nuoc va danh vi cua tu*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "bo sach thu ((nang ma) or (nang x)) hoi. hieu ((hien bach) OR (thien hach)) nuoc va danh vi cua tu*".