Clue: Scientific site over year favoured this when shorn of international networks (10)
Answer: LABYRINTHS
Explanation: Definition: networks
 LAB(short for "laboratory", a scientific site) **placed above**(over, in a down clue) YR(abbrev. for "year") + IN(favoured/popular, as in "the in thing") + "this" **minus**(when shorn of) "i"(abbrev. for "international").