全文获取类型
收费全文 | 1020篇 |
免费 | 99篇 |
出版年
2022年 | 7篇 |
2021年 | 13篇 |
2020年 | 6篇 |
2019年 | 13篇 |
2018年 | 15篇 |
2017年 | 9篇 |
2016年 | 27篇 |
2015年 | 31篇 |
2014年 | 40篇 |
2013年 | 64篇 |
2012年 | 48篇 |
2011年 | 63篇 |
2010年 | 24篇 |
2009年 | 36篇 |
2008年 | 60篇 |
2007年 | 58篇 |
2006年 | 46篇 |
2005年 | 40篇 |
2004年 | 51篇 |
2003年 | 36篇 |
2002年 | 36篇 |
2001年 | 22篇 |
2000年 | 22篇 |
1999年 | 20篇 |
1998年 | 13篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 15篇 |
1993年 | 11篇 |
1992年 | 10篇 |
1991年 | 18篇 |
1990年 | 11篇 |
1989年 | 19篇 |
1988年 | 9篇 |
1987年 | 10篇 |
1986年 | 22篇 |
1985年 | 14篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 8篇 |
1974年 | 9篇 |
1973年 | 13篇 |
1969年 | 6篇 |
排序方式: 共有1119条查询结果,搜索用时 325 毫秒
41.
42.
43.
Robert J. Klebe James R. Hall Pamella Rosenberger W. Daryl Dickey 《Experimental cell research》1977,110(2):419-425
This study is concerned with three aspects of the ionic requirements for cell attachment to collagen; namely (a) the divalent, (b) monovalent cation specificities and (c) pH optima for cell interaction with collagen. The divalent cation requirement for cell attachment to collagen can be sufficed by Ca2+, Mg2+ and certain transition group metals; whereas Ba2+, Sr2+, and polyamines are inactive. The pH optimum for cell attachment in this system occurs in the physiological range. The monovalent cation requirement for cell attachment to collagen is satisfied by isotonic NaCl, KCl, LiCl, NH4Cl, sucrose, and glucose. Pronounced inhibition of cell attachment occurs under both hypertonic and hypotonic conditions. 相似文献
44.
45.
The DNA-dependent RNA polymerases of Schneider 2-L cells of Drosophila melanogaster are described. These cells contain five readily detectable forms of this enzyme, polymerases Ia, Ib, IIIa, II, and IIIb, which elute from DEAE-Sephadex at 0.08, 0.12, 0.15, 0.20, and 0.22 m ammonium sulfate, respectively. RNA polymerases IIIa and IIIb, which each constitute about 5–10% of the total RNA polymerase activity in Drosophila embryos, are found to constitute 30 and 10%, respectively, of the total polymerase activity in cultured cells. The two form III polymerases are further characterized by in vitro response to divalent cations and ionic strength, template utilization, and sensitivity to -amanitin. Verification of the class III designation of these two polymerases is provided by their sensitivity to only very high levels of -amanitin (50% inhibition at approximately 800 µg/ml), their 10-fold greater activity on poly[d(A–T)], and their elution from DEAE-cellulose at lower ionic strengths than from DEAE-Sephadex.This work was supported by the Natural Sciences and Engineering Research Council. 相似文献
46.
47.
Influence of starch source on sporulation and enterotoxin production by Clostridium perfringens type A. 总被引:6,自引:6,他引:0 下载免费PDF全文
Of 16 different starch preparations tested, Clostridium perfringes NCTC 8798 yielded maximum sporulation and enterotoxin formation when ICN-soluble starch was included in Duncan and Strong sporulation medium. In general soluble starches were better than potato, corn, or arrowroot starch with regard to these two parameters. 相似文献
48.
N Clumeck A De Troyer R Naeije G Somers L Smekens E O Balasse 《BMJ (Clinical research ed.)》1976,2(6032):394-396
The clinical efficacy of small intravenous boluses of insulin in treating diabetic decompensation was tested in 23 patients presenting in either a ketoacidotic or a nonketotic diabetic coma. In addition to the usual ionic and fluid replacement, the patients received hourly intravenous injections of insulin 5 IU. This dose lowered blood glucose levels in all but two patients. In the patients who responded the percentage decrease in glycaemia was similar whatever the initial glucose concentration and averaged (+/-SE of mean) 50+/-3% in five hours. Close monitoring of insulin and glucose concentrations after intravenous insulin in three patients showed that despite the short half life of insulin the effect of the intravenous bolus lasted for about 60 minutes. The overall clinical effectiveness of this type of treatment is comparable to that of the other low-dose regimens. Owing to its simplicity, this technique of insulin administration seems most suitable for the routine treatment of diabetic coma. 相似文献
49.
50.
STATUS OF STUDIES ON FOSSIL MARINE MAMMALS 总被引:4,自引:0,他引:4