2021年7月29日 · The first day of bleeding is considered day one of your menstrual cycle. On this today, the hormone progesterone plunges, which causes the uterine lining to shed, AKA "your period". Often, a period lasts between 3 and 7 days.

Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of hormones .

2022年12月9日 · Your menstrual cycle begins on the first day of your period. Your cycle prepares your body for a possible pregnancy. The average cycle lasts between 24 and 38 days.

Menstruation — aka having your period — is when blood and tissue from your uterus comes out of your vagina. It usually happens every month. Problems with your period? For more accurate abortion options, please enter your age and the first day of your last period. Your information is private and anonymous.

period翻译：时间, 一段时间，时期, （人一生中或历史上的）时期;阶段, 课时，学时，一节（课）, 血, （妇女的）月经，经期, 符号, 句号…。 了解更多。

2021年2月26日 · Tracking your personal menstrual cycle can help you prepare for an upcoming period, inform you of the best time to have sex in order to conceive, and keep you in tune with your hormones. It is measured from the first day of one period to the first day of the following period and split into three different phases.

3 天之前 · Period is the upcoming sixth studio album by American singer Kesha. It is scheduled to be released independently through her own label Kesha Records on July 4, 2025. It is the first project since her departure from RCA and Kemosabe Records in December 2023. Background.

2019年7月30日 · All atoms have a period number assigned, even Hydrogen. Ok but how do we know what is the period name for an atom of H? If we know the symbol, let's say H, we may then open any periodic table and search for Hydrogen. Any decent periodic table should have the period numbers when you scroll left starting from the element you found.

Periodic Table of the Elements. Hydrogen was discovered by Sir Henry Cavendish (GB) in 1766. The origin of the name comes from the Greek words hydro and genes meaning water and generate. It is a colourless, odourless gas which burns and forms explosive mixtures in air and reacts violently with oxidants.

Hydrogen is the 1st element in the periodic table and has a symbol of H and atomic number of 1. It has an atomic weight of 1.008 and a mass number of 1. Hydrogen has one proton and zero neutrons in its nucleus, and one electron in one shell. It is located in group one, period one and block s of the periodic table.