全文获取类型
收费全文 | 8303篇 |
免费 | 950篇 |
国内免费 | 1篇 |
专业分类
9254篇 |
出版年
2022年 | 90篇 |
2021年 | 165篇 |
2020年 | 93篇 |
2019年 | 149篇 |
2018年 | 135篇 |
2017年 | 137篇 |
2016年 | 231篇 |
2015年 | 375篇 |
2014年 | 389篇 |
2013年 | 455篇 |
2012年 | 582篇 |
2011年 | 588篇 |
2010年 | 322篇 |
2009年 | 300篇 |
2008年 | 398篇 |
2007年 | 449篇 |
2006年 | 380篇 |
2005年 | 372篇 |
2004年 | 306篇 |
2003年 | 344篇 |
2002年 | 309篇 |
2001年 | 133篇 |
2000年 | 121篇 |
1999年 | 132篇 |
1998年 | 100篇 |
1997年 | 72篇 |
1996年 | 60篇 |
1995年 | 60篇 |
1994年 | 70篇 |
1993年 | 63篇 |
1992年 | 85篇 |
1991年 | 78篇 |
1990年 | 78篇 |
1989年 | 71篇 |
1988年 | 99篇 |
1987年 | 90篇 |
1986年 | 70篇 |
1985年 | 91篇 |
1984年 | 67篇 |
1983年 | 66篇 |
1979年 | 62篇 |
1978年 | 62篇 |
1977年 | 53篇 |
1976年 | 58篇 |
1974年 | 50篇 |
1973年 | 67篇 |
1972年 | 50篇 |
1971年 | 60篇 |
1970年 | 59篇 |
1969年 | 54篇 |
排序方式: 共有9254条查询结果,搜索用时 15 毫秒
21.
22.
23.
An experiment is described utilizing two 16-liter ionization chambers, fabricated from electrically conducting plastics which closely simulate air and human muscle, designed to minimize most of the errors inherent in the use of cavity chambers. A careful calibration was done, using a 226Ra source in 0.5 mm platinum, in an almost scatter-free environment which permitted the derivation of accurate corrections for scatter and air attenuation. Calibrations calculated from the physical measurements of the ion chambers are compared with the experimental calibrations. Values of Wbeta for air, and muscle gas and of tauRa are derived. 相似文献
24.
25.
26.
27.
Metabolic effects of phenethyl alcohol on mammalian cells 总被引:1,自引:0,他引:1
28.
29.
The versatile temporoparietal fascial flap: adaptability to a variety of composite defects 总被引:3,自引:0,他引:3
The unique properties of the temporoparietal fascial flap (TPFF) offer adaptability in reconstruction of a variety of composite defects. The broad, thin sheet of vascularized tissue may be transferred alone or as a carrier of subjacent bone or overlying skin and scalp. As a pedicled flap, it is ideal for defects of the orbital, malar, mandibular, and mastoid regions. As a free-tissue transfer, the large vessels and lack of bulk find broad utility in reconstruction of the extremities. This flap is our choice for reconstruction of the dorsal hand and non-weight-bearing surfaces of the foot. A viscous gliding surface decreases friction for tendon excursion. The thin contour is aesthetically superior to thicker flaps, allowing unmodified footwear or gloves. The pliable fascia convolutes into surface defects (e.g., bone craters) or drapes over skeletal frameworks (e.g., ear cartilage). The rich capillary network offers nutrition to saucerized bone, cartilage or tendon grafts, and overlying skin grafts. The geometry of the skull lends to fabrication of membranous bone for complex facial puzzles. The donor site is well disguised by hair growth. Twelve cases performed over a 2-year period demonstrate the versatility of this flap. These include complex foot reconstruction, ear and scalp avulsion, shotgun wound of the cheek and orbit, posttraumatic jaw recontouring, chronic osteomyelitis of the hand and foot, and acute resurfacing of dorsal hand with tendon reconstruction. 相似文献
30.
ACTH/MSH(4-10) (10 micrograms/kg/b.i.d.; IP), administered to pregnant Sprague-Dawley rats during gestational days (GD) 3 to 12, significantly increased the metabolic activity of extensor digitorum longus (EDL) muscle at postnatal day 14. ACTH/MSH peptide, administered from day of birth to postnatal day 13, had no effect on EDL muscle metabolic activity using the 2,3,5-triphenyltetrazolium chloride indicator. By postnatal day 30, no differences were seen between the early prenatally treated group and saline controls. These results confirm our previous electrophysiological studies that showed that early prenatal ACTH/MSH(4-10) administration accelerates EDL muscle maturation. 相似文献