Perhaps you should try some spelling variations:
thach thuc » thuc thuc, thanh thuy, cach thuc
danh kien » dinh kien, danh viet, linh kien
hac thuc » hoc thuc, ha thuc, thuc thuc
kien cuu » khien cua, khien cau, dien cuc
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
va danh » va dinh, va dan, va hanh
nang xa » nang x, lang xa, nang ma
cuu tre » cua tre, cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y ((nang xa) or (nang cao)) hoi. hieu van ((hac thuc) or (thach thuc)) va danh kien cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((nang xa) OR (nang cao)) hoi. hieu van ((hac thuc) OR (thach thuc)) va danh kien cuu tre.
• Adding a wildcard symbol may retrieve word variants: so sach y ((nang xa) or (nang cao)) hoi. hieu van ((hac thuc) or (thach thuc)) va danh kien cuu tre*.