Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
doc sach » hoc sach, toc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
van pham » san pham, van phan, van phat
viet cua » viec cua, viet qua, biet cua
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
viet ca » viet co, viet a, viet nam
viet ha » viet nam
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: doc sach ky nang x hoi. hieu van pham thuc va danh ((((viet cua) or (viet ca))) or (viet ha)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky nang x hoi. hieu van pham thuc va danh ((((viet cua) OR (viet ca))) OR (viet ha)) tre.
• Adding a wildcard symbol may retrieve word variants: doc sach ky nang x hoi. hieu van pham thuc va danh ((((viet cua) or (viet ca))) or (viet ha)) tre*.