Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh hai » thanh hai, nhanh hai, hang hai
van hanh » van thanh, ban hanh, van anh
duc van » duc va, duc tan, duc manh
cua tuc » cua duc, cua tu, cua thuoc
cao hoi » cau hoi, co hoi, cao hoc
y nang » ky nang, ly nang, v nang
ve cam » ve cham, ve cac, ve cai
cua te » cua tu
va cam » va cham, va cac, va cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y nang cao hoi. hieu ((ve cam) OR (va cam)) duc van hanh hai ((cua te) or (cua tuc))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang cao hoi. hieu ((ve cam) OR (va cam)) duc van hanh hai ((cua te) OR (cua tuc)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang cao hoi. hieu ((ve cam) OR (va cam)) duc van hanh hai ((cua te) or (cua tuc))".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang cao hoi. hieu ((ve cam) OR (va cam)) duc van hanh hai ((cua te) or (cua tuc))*.