Perhaps you should try some spelling variations:
thai cua » than cua, tai cuc, tri cua
dan thai » dang thai, dan thi, dan than
dao nuoc » dat nuoc, dao cuoc, dau nuoc
hieu van » hieu va, thien van, lieu va
sach ky » sach y, sach ty, sach kem
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, mang xa
sac ky » cac ky, sai ky
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 ky) OR (sac ky)) ((nang xa) or (nang ma)) hoi. hieu van dao nuoc va dan thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) ((nang xa) OR (nang ma)) hoi. hieu van dao nuoc va dan thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sac ky)) ((nang xa) or (nang ma)) hoi. hieu van dao nuoc va dan thai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sac ky)) ((nang xa) or (nang ma)) hoi. hieu van dao nuoc va dan thai cua tre*.