Perhaps you should try some spelling variations:
nam truoc » nam thuoc, lam truoc, nam truc
cau treo » cau theo, cau triet, cau trieu
danh hai » dang hai, lanh hai, manh hai
truoc va » truc va, thuoc va, truong va
hieu van » hieu va, thien van, lieu va
cau tren » cu tren, dau tren, ca tren
sang ma » tang ma, nang ma, sang tao
sach ly » sach y, sach lo, sach ty
va danh » va dinh, va dan, va hanh
su sach » so sach, vu sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ly ((mang may) or (sang ma)) hoi. hieu van nam truoc va danh hai ((cau treo) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly ((mang may) OR (sang ma)) hoi. hieu van nam truoc va danh hai ((cau treo) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ly ((mang may) or (sang ma)) hoi. hieu van nam truoc va danh hai ((cau treo) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: su sach ly ((mang may) or (sang ma)) hoi. hieu van nam truoc va danh hai ((cau treo) OR (cau tren))*.