Early initiation of sexual activity: a risk factor for sexually transmitted diseases, HIV infection, and unwanted pregnancy among university students in China
2005 ◽
Vol 192
(8)
◽
pp. 1315-1317
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1990 ◽
Vol 5
(4)
◽
pp. 431-448
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Keyword(s):
1999 ◽
Vol 75
(3)
◽
pp. 191-191
◽
2005 ◽
Vol 118
(6)
◽
pp. 571-577
◽
Keyword(s):