全文获取类型
收费全文 | 8223篇 |
免费 | 531篇 |
国内免费 | 12篇 |
出版年
2023年 | 17篇 |
2022年 | 75篇 |
2021年 | 153篇 |
2020年 | 95篇 |
2019年 | 119篇 |
2018年 | 174篇 |
2017年 | 154篇 |
2016年 | 280篇 |
2015年 | 412篇 |
2014年 | 547篇 |
2013年 | 583篇 |
2012年 | 678篇 |
2011年 | 618篇 |
2010年 | 351篇 |
2009年 | 345篇 |
2008年 | 486篇 |
2007年 | 477篇 |
2006年 | 451篇 |
2005年 | 406篇 |
2004年 | 388篇 |
2003年 | 333篇 |
2002年 | 290篇 |
2001年 | 212篇 |
2000年 | 189篇 |
1999年 | 137篇 |
1998年 | 57篇 |
1997年 | 42篇 |
1996年 | 43篇 |
1995年 | 52篇 |
1994年 | 31篇 |
1993年 | 22篇 |
1992年 | 64篇 |
1991年 | 45篇 |
1990年 | 49篇 |
1989年 | 42篇 |
1988年 | 34篇 |
1987年 | 28篇 |
1986年 | 25篇 |
1985年 | 28篇 |
1984年 | 27篇 |
1983年 | 16篇 |
1982年 | 19篇 |
1981年 | 11篇 |
1979年 | 19篇 |
1978年 | 18篇 |
1976年 | 10篇 |
1975年 | 11篇 |
1974年 | 16篇 |
1973年 | 17篇 |
1972年 | 10篇 |
排序方式: 共有8766条查询结果,搜索用时 328 毫秒
241.
Background
In evaluating hearing disability in medicolegal work, the apportionment of age- and gender-related sensorineural hearing loss should be considered as a prior factor, especially for the elderly. However, in the literature written in the English language no studies have reported on the age- and gender-related mean hearing threshold for the South Korean population.Objective
This study aimed to identify the mean hearing thresholds in the South Korean population to establish reference data and to identify the age- and gender-related characteristics.Methods
This study is based on the Korea National Health and Nutrition Examination Survey (KNHANES) 2010–2012, which was conducted by the Korean government, the data of which was disclosed to the public. A total of 15,606 participants (unweighted) representing 33,011,778 Koreans (weighted) with normal tympanic membrane and no history of regular or occupational noise exposure were selected and analyzed in this study. The relationship between the hearing threshold level and frequency, age, and gender was investigated and analyzed in a highly-screened population by considering the sample weights of a complex survey design.Results
A gender ratio difference was found between the unweighted and the weighted designs: male:female, 41.0%: 59.0% (unweighted, participants) vs. 47.2%:52.8% (weighted, representing population). As age increased, the hearing threshold increased for all frequencies. Hearing thresholds of 3 kHz, 4 kHz, and 6 kHz showed a statistical difference between both genders for people older than 30, with the 4 kHz frequency showing the largest difference. This paper presents details about the mean hearing threshold based on age and gender.Conclusions
The data from KNHANES 2010–2012 showed gender differences at hearing thresholds of 3 kHz, 4 kHz, and 6 kHz in a highly-screened population. The most significant gender difference in relation to hearing threshold was observed at 4 kHz. The hearing thresholds at all of the tested frequencies worsened with increasing age. The mean hearing thresholds suggested in this study will be useful for the formulation of healthcare-related hearing policies and used as reference data for disability ratings for hearing loss due to various causes. 相似文献242.
Figen Seymen Youn Jung Kim Ye Ji Lee Jenny Kang Tak-Heun Kim Hwajung Choi Mine Koruyucu Yelda Kasimoglu Elif Bahar Tuna Koray Gencay Teo Jeon Shin Hong-Keun Hyun Young-Jae Kim Sang-Hoon Lee Zang Hee Lee Hong Zhang Jan C-C. Hu James P. Simmer Eui-Sic Cho Jung-Wook Kim 《American journal of human genetics》2016,99(5):1199-1205
243.
244.
245.
246.
Mitigation of ammonia inhibition by internal dilution in high‐rate anaerobic digestion of food waste leachate and evidences of microbial community response
下载免费PDF全文
![点击此处可从《Biotechnology and bioengineering》网站下载免费的PDF全文](/ch/ext_images/free.gif)
247.
248.
Woo-Ri Kang Min-Ju Seo Jung-Ung An Kyung-Chul Shin Deok-Kun Oh 《Biotechnology letters》2016,38(5):817-823
Objective
To produce δ-decalactone from linoleic acid by one-pot reaction using linoleate 13-hydratase with supplementation with whole Yarrowia lipolytica cells.Results
Whole Y. lipolytica cells at 25 g l?1 produced1.9 g l?1 δ-decalactone from 7.5 g 13-hydroxy-9(Z)-octadecenoic acid l?1 at pH 7.5 and 30 °C for 21 h. Linoleate 13-hydratase from Lactobacillus acidophilus at 3.5 g l?1 with supplementation with 25 g Y. lipolytica cells l?1 in one pot at 3 h produced 1.9 g l?1 δ-decalactone from 10 g linoleic acid l?1 via 13-hydroxy-9(Z)-octadecenoic acid intermediate at pH 7.5 and 30°C after 18 h, with a molar conversion yield of 31 % and productivity of 106 mg l?1 h?1.Conclusion
To the best of our knowledge, this is the first production of δ-decalactone using unsaturated fatty acid.249.
250.