Table 2.
The 20 most frequently used title words in the whole period and different sub-periods.
| Words in title | TP | 1980–2011 | 1980–1987 | 1988–1995 | 1996–2003 | 2004–2011 |
|---|---|---|---|---|---|---|
| Rank (%) | Rank (%) | Rank (%) | Rank (%) | Rank (%) | ||
| Synthesis | 244 | 1 (9.0) | 12 (2.7) | 8 (3.0) | 1 (10) | 1 (9.0) |
| Carbon | 140 | 2 (5.2) | N/A | 85 (0.85) | 2 (5.7) | 2 (5.9) |
| Nanotubes | 113 | 3 (4.2) | N/A | N/A | 3 (5.3) | 4 (4.0) |
| Nanoparticles | 88 | 4 (3.3) | N/A | N/A | 6 (3.0) | 3 (4.6) |
| Characterization | 76 | 5 (2.8) | 52 (1.3) | 39 (1.3) | 5 (3.3) | 13 (2.6) |
| Nanowires | 71 | 6 (2.6) | N/A | N/A | 4 (4.3) | 88 (1.3) |
| Structure | 65 | 7 (2.4) | N/A | 39 (1.3) | 7 (2.9) | 21 (2.2) |
| Patients | 64 | 8 (2.4) | 5 (4.0) | 1 (8.1) | 14 (2.3) | 109 (1.1) |
| Networks | 63 | 9 (2.3) | N/A | N/A | 19 (2.0) | 5 (3.5) |
| Reaction | 62 | 10 (2.3) | 5 (4.0) | 18 (1.7) | 10 (2.5) | 26 (2.0) |
| Films | 61 | 11 (2.3) | 52 (1.3) | 18 (1.7) | 12 (2.4) | 18 (2.3) |
| Stability | 60 | 12 (2.2) | N/A | 236 (0.43) | 12 (2.4) | 13 (2.6) |
| Complexes | 58 | 13 (2.1) | 52 (1.3) | 18 (1.7) | 8 (2.7) | 52 (1.5) |
| ZnO | 58 | 13 (2.1) | N/A | N/A | 30 (1.7) | 6 (3.4) |
| Activity | 57 | 15 (2.1) | 52 (1.3) | 85 (0.85) | 26 (1.8) | 10 (2.9) |
| Photocatalytic | 57 | 15 (2.1) | N/A | N/A | 30 (1.7) | 8 (3.3) |
| China | 56 | 17 (2.1) | 5 (4.0) | 12 (2.1) | 9 (2.6) | 88 (1.3) |
| Coordination | 54 | 18 (2.0) | 52 (1.3) | N/A | 33 (1.6) | 9 (3.0) |
| Oxide | 54 | 18 (2.0) | N/A | N/A | 15 (2.2) | 18 (2.3) |
| Surface | 54 | 18 (2.0) | N/A | 85 (0.85) | 19 (2.0) | 17 (2.4) |
N/A, not available; %, the percentage of the frequency of a given word in title to the total number of articles.