Perhaps you should try some spelling variations:
sach tham » sach nha
thu sach » tu sach, thuat sach, thuoc sach
pham duy » pham duc
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
sang ma » nang ma, sang tao, mang may
tang ma » mang may, tang van
duy van » duy vat, dung van
hieu vu » hieu va, hieu ve, hieu su
vu pham » su pham, vi pham, vu kham
tai va » thai va, mai va, tri va
thiet* » thieu*

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 tham ((((sang ma) OR (tang ma))) or (nang x)) hoi. hieu vu pham duy van hanh tai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach tham ((((sang ma) OR (tang ma))) OR (nang x)) hoi. hieu vu pham duy van hanh tai va thiet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach tham ((((sang ma) OR (tang ma))) or (nang x)) hoi. hieu vu pham duy van hanh tai va thiet*".