Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
hac thuc » hoc thuc, ha thuc, thach thuc
vinh cuu » dinh cuu, sinh cua, dinh cu
tu sach » su sach, te sach, tu cach
hieu va » lieu va, hieu qua
vat dan » va dan, van dan, vat ran
va hac » van hac, va khac, va cac
vi cuu » vi luu
x hoi » xa hoi, o hoi, x ho

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) OR (thu sach)) ky nang x hoi. hieu va hac thuc vat dan ((vi cuu) or (vinh cuu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang x hoi. hieu va hac thuc vat dan ((vi cuu) OR (vinh cuu)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ky nang x hoi. hieu va hac thuc vat dan ((vi cuu) or (vinh cuu)) tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ky nang x hoi. hieu va hac thuc vat dan ((vi cuu) or (vinh cuu)) tre*.