Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thuoc ban » thuoc tan, thuoc dang, thu ban
nam thuoc » nam thuc, nam thu, nha thuoc
hieu van » hieu va, thien van, lieu va
nang mai » nang ma, nang tai, lang mai
mai hoi » mai khoi, dai hoi, lai hoi
sach ly » sach y, sach lo, sach hay
sach ty » sach y, sach tu, sach thu
ve cuu » ve cau, ve cua, ve cum
ve chu » ve cau, va chu, ve che

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 ly) OR (sach ty)) nang mai hoi. hieu van nam thuoc ban thanh ((ve cuu) or (ve chu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ly) OR (sach ty)) nang mai hoi. hieu van nam thuoc ban thanh ((ve cuu) OR (ve chu)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ly) OR (sach ty)) nang mai hoi. hieu van nam thuoc ban thanh ((ve cuu) or (ve chu)) tre".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ly) OR (sach ty)) nang mai hoi. hieu van nam thuoc ban thanh ((ve cuu) or (ve chu)) tre*.