Examples of powerful LaTeX packages and techniques in use — a great way to learn LaTeX by example. Search or browse below.

Equations For Paper
I want to see if this publishes it in MathML so I can cut & paste from there to other formats.
CK Harnett

Math
Hello! Here's how this works:
You edit the source code here on the left, and the preview on the
right shows you the result within a few seconds.
Bookmark this page and share the URL with your co-authors. They
can edit at the same time!
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styles using the files menu.
This presentation is made with the Beamer package. For tutorials
and more info, see:
http://en.wikipedia.org/wiki/Beamer_(LaTeX)
We're still in beta. Please leave some feedback using the link at
the top left of this page.
Enjoy!
David James

IEEE MTT-S Conference (IMS 2013 example)
With Overleaf, edit online instantly this IEEE MTT-S Conference Paper (IMS 2013), and download a PDF version.
This project is also available on my web site:
Tibault Reveyrand

Cyrillic Fonts: Excerpt from Poems for Akhmatova
A Russian poem demonstrating how to use Cyrillic fonts with UTF-8 encoding and the babel package.
writeLaTeX

Using "import" to facilitate main file in subfolder
Some authors prefer to place their manuscript LaTeX source files in a subfolder, and other research artefacts (figures, tables, etc) in another subfolder. This example shows how this workflow can be maintained on Overleaf, by providing a top-level main.tex that pulls in the real main LaTeX file from the subfolder using the import package.
LianTze Lim

Capa do trabalho
Apenas a capa.
Thales Domingues

BangBienthien
Đây là Bảng biến thiên
Bùi Minh Quang

Ukázková prezentace pro workshop České Budějovice
Ukázková prezentace pro účastníky workshopu na konferenci v Českých Budějovicích 2015.
(Sample presentation to workshop participants at a conference in the Czech Budejovice 2015.)
Roman Plch

Zhilong He's CV
改自Deedy CV的中文简历,可附头像。
Zhilong He