Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
nhan luu » nhan luc, nhan lupus, nhan luan
cau tren » cu tren, dau tren, ca tren
nang doc » nang luc
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
nang co » nang cao, nang noi, nang hoc
ve nhan » ve nha, de nhan, va nhan
va cau » van cau, va cac, va dau

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 ky ((nang co) or (nang doc)) hoc. hieu ve nhan luu ((van hanh) OR (ban hanh)) va cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang co) OR (nang doc)) hoc. hieu ve nhan luu ((van hanh) OR (ban hanh)) va cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((nang co) or (nang doc)) hoc. hieu ve nhan luu ((van hanh) OR (ban hanh)) va cau tren".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang co) or (nang doc)) hoc. hieu ve nhan luu ((van hanh) OR (ban hanh)) va cau tren*.