全文获取类型
收费全文 | 1571篇 |
免费 | 196篇 |
出版年
2021年 | 13篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 14篇 |
2016年 | 17篇 |
2015年 | 43篇 |
2014年 | 50篇 |
2013年 | 67篇 |
2012年 | 91篇 |
2011年 | 92篇 |
2010年 | 54篇 |
2009年 | 66篇 |
2008年 | 64篇 |
2007年 | 81篇 |
2006年 | 85篇 |
2005年 | 61篇 |
2004年 | 70篇 |
2003年 | 59篇 |
2002年 | 78篇 |
2001年 | 45篇 |
2000年 | 44篇 |
1999年 | 45篇 |
1998年 | 19篇 |
1997年 | 13篇 |
1996年 | 19篇 |
1993年 | 20篇 |
1992年 | 27篇 |
1991年 | 22篇 |
1990年 | 29篇 |
1989年 | 24篇 |
1988年 | 32篇 |
1987年 | 24篇 |
1986年 | 14篇 |
1985年 | 17篇 |
1984年 | 18篇 |
1983年 | 20篇 |
1982年 | 15篇 |
1981年 | 11篇 |
1980年 | 16篇 |
1979年 | 13篇 |
1978年 | 16篇 |
1977年 | 13篇 |
1976年 | 14篇 |
1975年 | 16篇 |
1974年 | 14篇 |
1972年 | 12篇 |
1971年 | 12篇 |
1968年 | 11篇 |
1967年 | 10篇 |
1966年 | 12篇 |
排序方式: 共有1767条查询结果,搜索用时 15 毫秒
991.
G. E. Kempson C. J. Spivey S. A. V. Swanson M. A. R. Freeman 《Journal of biomechanics》1971,4(6):597-608
Using the apparatus and technique described in an earlier paper, (Kempson et al. 1971), indentation tests were performed on areas of cartilage of 0·125 in dia., in situ on, and distributed evenly over, the cartilage surface of the human femoral head. Curves of indentation vs. time were plotted for a physiological stress of approximately 400 lbf/in2. (28·2 kgf/cm2, 2·36 MN/m2). The stiffness of each area of cartilage was calculated from the appropriate indentation value, in the form of a creep modulus at 2 sec, using the equations described in the previous paper (see Appendix). Layered maps and histograms showing the variation of both cartilage stiffness and indentation are presented. 相似文献
992.
993.
Mutations termed das were isolated originally (Hercules and Wiberg, 1971) as partial suppressors of mutants in phage T4 genes 46 and 47. Since mutants in genes 46, 47, and 59 exhibit both an early arrest of phage DNA synthesis and the loss of this arrest in the presence of chloramphenicol or of mutations of T4 genes 33 and 55, we asked whether a das mutation can also suppress a gene 59 mutant. We find that it cannot--either at the level of phage production or DNA synthesis. 相似文献
994.
The objectives of this study were to: 1) develop an electroejaculation procedure for collecting semen from the La Plata three‐banded armadillo (Tolypeutes matacus), and 2) characterize basal reproductive traits, including sperm concentration, motility, morphology, acrosomal status, and viability. Three male armadillos were each electroejaculated on one to five occasions. Fluid containing spermatozoa was recovered during each attempt, and high proportions (>75%) of morphologically normal spermatozoa were seen in all analyzed samples. Two fluorescent stains (FITC‐PNA and Hoechst 33258) appeared to be effective for assessing acrosomal status and viability, respectively, in this species. Sperm concentration and motility were usually low, and urine contamination was a persistent problem—possibly due to anesthesia, unique reproductive anatomy, and/or improper probe placement. Poor sperm recovery, urine contamination, and sensitivity of spermatozoa to culture medium must be addressed before electroejaculation can be used routinely in the La Plata three‐banded armadillo. Zoo Biol 21:481–487, 2002. © 2002 Wiley‐Liss, Inc. 相似文献
995.
996.
Somatomedin C and arginine: implicit connections between mutually isolated literatures 总被引:7,自引:0,他引:7
D R Swanson 《Perspectives in biology and medicine》1990,33(2):157-186
997.
Rosemarie D. Lincoln 《BMJ (Clinical research ed.)》1974,3(5929):521-522
998.
999.
1000.