Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
cau nuoc » cap nuoc, cac nuoc, dau nuoc
dan thai » dang thai, dan thi, dan than
thai cuu » thai cua, tai cuc, thi cuc
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
va dan » ca dan, va dao, 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: tu sach y ((nang x) or (nang ma)) hoi. ((hieu van) OR (hieu va)) cau nuoc va dan thai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang x) OR (nang ma)) hoi. ((hieu van) OR (hieu va)) cau nuoc va dan thai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang x) or (nang ma)) hoi. ((hieu van) OR (hieu va)) cau nuoc va dan thai cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang x) or (nang ma)) hoi. ((hieu van) OR (hieu va)) cau nuoc va dan thai cuu tre*.