Perhaps you should try some spelling variations:
sach tham » sach nha
danh van » doanh van, dang van, dinh van
dau tren » dau tien, dat tren, dau tieng
tu sach » thu sach, su sach, te sach
ve pham » v pham, ve phan, ve phat
va danh » va dinh, va dan, va hanh
van dau » van dao, phan dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach tham ((mang may) or (nang x)) hoi. hieu ((ve pham) or (vi pham)) day va danh van dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tham ((mang may) OR (nang x)) hoi. hieu ((ve pham) OR (vi pham)) day va danh van dau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach tham ((mang may) or (nang x)) hoi. hieu ((ve pham) or (vi pham)) day va danh van dau tren*.