全文获取类型
收费全文 | 2262篇 |
免费 | 221篇 |
国内免费 | 1篇 |
出版年
2023年 | 22篇 |
2022年 | 41篇 |
2021年 | 83篇 |
2020年 | 33篇 |
2019年 | 44篇 |
2018年 | 72篇 |
2017年 | 55篇 |
2016年 | 68篇 |
2015年 | 89篇 |
2014年 | 111篇 |
2013年 | 158篇 |
2012年 | 169篇 |
2011年 | 130篇 |
2010年 | 88篇 |
2009年 | 66篇 |
2008年 | 90篇 |
2007年 | 72篇 |
2006年 | 83篇 |
2005年 | 76篇 |
2004年 | 55篇 |
2003年 | 58篇 |
2002年 | 50篇 |
2001年 | 44篇 |
2000年 | 29篇 |
1999年 | 34篇 |
1998年 | 16篇 |
1997年 | 22篇 |
1996年 | 18篇 |
1995年 | 12篇 |
1994年 | 15篇 |
1993年 | 19篇 |
1992年 | 39篇 |
1991年 | 33篇 |
1990年 | 37篇 |
1989年 | 36篇 |
1988年 | 25篇 |
1987年 | 27篇 |
1986年 | 38篇 |
1985年 | 31篇 |
1984年 | 33篇 |
1983年 | 19篇 |
1982年 | 20篇 |
1981年 | 20篇 |
1980年 | 15篇 |
1979年 | 25篇 |
1978年 | 17篇 |
1977年 | 20篇 |
1976年 | 20篇 |
1975年 | 25篇 |
1974年 | 24篇 |
排序方式: 共有2484条查询结果,搜索用时 250 毫秒
91.
92.
93.
94.
Ram S. Verma Arvind Babu Sundari Chemitiganti Harvey Dosik 《Molecular & general genetics : MGG》1986,202(3):339-341
Summary A possible cause of non-disjunction of chromosome 21 in Down Syndromes has been cytogenetically evaluated by examining the parents by Ag-staining technique. In all the cases studied so far, the contributing parents have active ribosomal cistrons on both chromosomes 21 i.e. both chromosomes are stained positively by silver staining. These results show that the active NORs might play an essential role in meiotic non-disjunction. Furthermore, the preliminary results demonstrate that the acrocentric associations of homologous and non-homologous nature involving chromosome 21 are the most frequent in the contributing parent which may further indicate the role of multiple cellular factors affecting the associations in promoting the non-disjunction in addition to active NORs. The possible mechanisms regarding the non-disjunction of chromosome 21 have been described.Presented at the 34th Annual Meeting of the American Society of Human Genetics, Norfolk, VA, USA 相似文献
95.
Amol A. Verma Tejasvi Hora Hae Young Jung Michael Fralick Sarah L. Malecki Lauren Lapointe-Shaw Adina Weinerman Terence Tang Janice L. Kwan Jessica J. Liu Shail Rawal Timothy C.Y. Chan Angela M. Cheung Laura C. Rosella Marzyeh Ghassemi Margaret Herridge Muhammad Mamdani Fahad Razak 《CMAJ》2021,193(23):E859
96.
97.
98.
99.
Studies were conducted to determine the effect of iodine infusion on the luteal function of goats, as evident by blood progesterone concentration, and on plasma PGF2a levels. Ten cycling mixed breed goats were synchronized for estrus by PGF2a (5 mg) and given a single intrauterine iodine infusion on day 5 and on day 15 of the estrous cycle. Iodine infusion on day 5 (group II) resulted in shorter estrous length (8.2 days) and a 7-fold increase in plasma PGF2a concentration as compared to control animals (group I) given distilled water infusion. Similar infusion on day 15 (group III), on the other hand, failed to alter the estrous cycle length but induced a moderate increase in PGF2a concentration which lasted only for a brief period. The progesterone levels declined concomitantly as PGF2a levels rose after iodine infusion in group II animals but failed to decline until after 24 hours in group III animals. The studies indicate that the endometrium reacts to the chemical stimuli and releases PGF2a which, in turn, alters the luteal function. 相似文献
100.
Rodrigues Vereena Kumar Amit Gokul Sivaraman Verma Ram S. Rahman Laiq ur Sundaresan Velusamy 《In vitro cellular & developmental biology. Plant》2020,56(4):526-537
In Vitro Cellular & Developmental Biology - Plant - An efficient in vitro propagation and synthetic seed production protocol was established for the conservation of Decalepis salicifolia (Bedd.... 相似文献