nmap -PN yandex.ru
Nmap scan report for yandex.ru (87.250.251.11)
Host is up (0.0046s latency).
Hostname yandex.ru resolves to 6 IPs. Only scanned 87.250.251.11
Not shown: 998 filtered ports
PORT    STATE SERVICE
80/tcp  open  http
443/tcp open  https

Nmap done: 1 IP address (1 host up) scanned in 5.11 seconds

[shaggycat@desktop2 SOURCES]$ man nmap | egrep -e '-PN'
             -PN: Расценивать все хосты как работающие -- пропустить обнаружение хостов