全文获取类型
收费全文 | 406345篇 |
免费 | 46256篇 |
国内免费 | 172篇 |
出版年
2018年 | 3516篇 |
2017年 | 3505篇 |
2016年 | 4703篇 |
2015年 | 6245篇 |
2014年 | 7267篇 |
2013年 | 10875篇 |
2012年 | 12150篇 |
2011年 | 12283篇 |
2010年 | 8217篇 |
2009年 | 7665篇 |
2008年 | 11144篇 |
2007年 | 11316篇 |
2006年 | 10877篇 |
2005年 | 10271篇 |
2004年 | 10171篇 |
2003年 | 9844篇 |
2002年 | 9602篇 |
2001年 | 18906篇 |
2000年 | 19094篇 |
1999年 | 15507篇 |
1998年 | 5428篇 |
1997年 | 5693篇 |
1996年 | 5502篇 |
1995年 | 5001篇 |
1994年 | 5122篇 |
1993年 | 4982篇 |
1992年 | 12930篇 |
1991年 | 12348篇 |
1990年 | 12284篇 |
1989年 | 12245篇 |
1988年 | 11146篇 |
1987年 | 10602篇 |
1986年 | 9827篇 |
1985年 | 9871篇 |
1984年 | 7999篇 |
1983年 | 6962篇 |
1982年 | 5292篇 |
1981年 | 4670篇 |
1980年 | 4551篇 |
1979年 | 7671篇 |
1978年 | 5942篇 |
1977年 | 5295篇 |
1976年 | 5115篇 |
1975年 | 5530篇 |
1974年 | 5780篇 |
1973年 | 5705篇 |
1972年 | 5167篇 |
1971年 | 4568篇 |
1970年 | 4034篇 |
1969年 | 3733篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
231.
CHELATOR: an improved method for computing metal ion concentrations in physiological solutions. 总被引:17,自引:0,他引:17
An algorithm is presented for the calculation of metal ion concentrations from given total metal concentrations (and vice versa) in physiological media containing metal-chelating compounds. In such media, conditions differ from those used for stability constant determination of metal-chelator equilibria; therefore calculated metal ion concentrations are incorrect. We recompute stability constants to reflect the effects of ionic strength and temperature of physiological solutions. Twelve different equilibria can be considered per metal-chelator pair. The computer program also calculates the contribution of ionized species of metals, chelator, complexes and pH buffers to ionic strength. Measurements with a Ca-selective electrode and with fura-2 show that calculated ionic Ca2+ concentrations are correct from 10 nM up to the millimolar range. The importance of the correct calculation of metal ion concentrations in physiological experiments is demonstrated by data, and derived kinetic parameters, on Na+/Ca2+ exchange and the ATP-dependent Ca2+ pump of enterocyte plasma membrane vesicles. The program is written in Turbo Pascal and will run on IBM-compatible computers. It is menu-driven and supports the use of a Microsoft mouse. 相似文献
232.
M Ravnik-Glavac P Gasparini B Peterlin M Strukelj D Glavac N Canki-Klain P F Pignatti R Komel 《Annales de génétique》1992,35(2):85-88
The authors used polymerase chain reaction to analyse 56 Slovenian cystic fibrosis (CF) chromosomes for the presence of delta F508 and eight other most frequent mutations located in exons 7,11 and 20 (R347P, R334W, G551D, R553X, S549RA, S549RT, S549I and S1255X) of the CF gene. We also determined the frequency of haplotypes associated with CF for six linked RFLP markers (MetD/TaqI, MetH/TaqI, XV-2c/TaqI, KM-19/PstI, MP6d9/MspI and J3.11/MspI) in 27 Slovenian CF families. delta F508 mutation was present in 55.4 percent of the CF chromosomes. No case of the other mutations were detected in the sample of tested CF chromosomes. A very high degree of association (0.88) has been found between DNA marker MetH and CF (as measured by the Yule's association coefficient) in our population. Using the RFLP markers XV-2c and KM-19, we found that 85% of delta F508 mutated chromosomes have a single 1 2 (B) haplotype, and that this haplotype is present on only 15.4 percent of CF chromosomes without this deletion. 相似文献
233.
234.
G Amiconi E Antonini M Brunori E Chiancone P Vecchini 《The Journal of biological chemistry》1971,246(6):1883-1888
235.
236.
237.
P. J. Hogarth 《Journal of fish biology》1973,5(1):109-113
Advanced embryos of the viviparous poeciliid fish Xiphophorus hellerii (swordtail) were removed from the site of gestation within the ovary and re-implanted into the peritoneal cavities of unrelated immunologically competent adults of the same species. Most of those transplanted with intact fertilization membranes were normal in appearance, and many were clearly still alive. Those transplanted without a fertilization membrane were all dead, with lymphocyte infiltration and other evidence of rejection as allografts. The integrity of the membrane in late pregnancy was indicated by swelling of follicles in hypoosmotic liquid. It was concluded that the fertilization membrane is capable of protecting an antigenically foreign embryo in an immunologically hostile environment, and that it probably serves this function during normal pregnancy. 相似文献
238.
239.
240.