Perhaps you should try some spelling variations:
hoc viet » hoc hien
manh vai » manh hai, manh va, manh khai
dan manh » dang manh, doan manh, van manh
thuc dan » thuc hanh, hoc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
sach ty » sach y, sach tu, sach thu
ca viet » va viet, co viet, hoa viet
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
hieu ve » hieu van
ty nang » ky nang, ty xang, ty hang
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 ty nang x hoi. ((hieu ve) or (hieu va)) nam thuc dan manh vai ((ca viet) or (hoc viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang x hoi. ((hieu ve) OR (hieu va)) nam thuc dan manh vai ((ca viet) OR (hoc viet)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang x hoi. ((hieu ve) or (hieu va)) nam thuc dan manh vai ((ca viet) or (hoc viet))*.