Talvez deva tentar algumas variações de ortografia:
dna clamp » a clamp (Expandir a Pesquisa)
can ngoc » van ngoc (Expandir a Pesquisa), tran ngoc (Expandir a Pesquisa), phan ngoc (Expandir a Pesquisa)
cong dan » cong doan (Expandir a Pesquisa), song dan (Expandir a Pesquisa), tong dan (Expandir a Pesquisa)
dan ngoc » dang ngoc (Expandir a Pesquisa), doan ngoc (Expandir a Pesquisa), van ngoc (Expandir a Pesquisa)
can now » can new (Expandir a Pesquisa), can non (Expandir a Pesquisa)
clamp a » clamp _ (Expandir a Pesquisa), clamp j (Expandir a Pesquisa)
et cong » et congo (Expandir a Pesquisa), et con (Expandir a Pesquisa), viet cong (Expandir a Pesquisa)
j dna » _ dna (Expandir a Pesquisa), a dna (Expandir a Pesquisa), 1 dna (Expandir a Pesquisa)
a non » _ non (Expandir a Pesquisa)
j et » j e (Expandir a Pesquisa), j st (Expandir a Pesquisa)
mat » math (Expandir a Pesquisa), meat (Expandir a Pesquisa), mast (Expandir a Pesquisa)

You can also try:

• Europeana
• Digital Public Library of America
• CORE

Pode obter mais resultados ajustando a pesquisa.

• Performing a fuzzy search may retrieve terms with similar spellings: (( _ mat amin ((can now) or (can ngoc)) ) or ((( j dna clamp a non ) or ( j et cong dan ngoc ))))~.
• Se usar operadores Booleanos, por favor insira-os com letras MAIÚSCULAS: (( _ mat amin ((can now) OR (can ngoc)) ) OR ((( j dna clamp a non ) OR ( j et cong dan ngoc )))).
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (( _ mat amin ((can now) or (can ngoc)) ) or ((( j dna clamp a non ) or ( j et cong dan ngoc ))))*.