Perhaps you should try some spelling variations:
black david » brock david, blanc david, baldock david
mark david » mare davide, parker david
young ghi » young choi, hong ghi, young hr
young get » young let, young ages, young men
lang tan » liang tan, lang lang, tang tang
tan yang » dan yang, tan ying, tan yong
yang li » yang lin, yang di, yang xi
li gene » i gene, l1 gene, iii gene

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

• If you are trying to use Boolean operators, they must be ALL CAPS: lang tan yang li gene ((black david) OR (mark david)) ((young ghi) OR (young get)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "lang tan yang li gene ((black david) or (mark david)) ((young ghi) OR (young get)) ;~".
• Adding a wildcard symbol may retrieve word variants: lang tan yang li gene ((black david) or (mark david)) ((young ghi) OR (young get)) ;*.