全文获取类型
收费全文 | 2579篇 |
免费 | 189篇 |
国内免费 | 107篇 |
出版年
2023年 | 29篇 |
2022年 | 36篇 |
2021年 | 68篇 |
2020年 | 76篇 |
2019年 | 84篇 |
2018年 | 76篇 |
2017年 | 76篇 |
2016年 | 75篇 |
2015年 | 104篇 |
2014年 | 133篇 |
2013年 | 159篇 |
2012年 | 107篇 |
2011年 | 138篇 |
2010年 | 78篇 |
2009年 | 85篇 |
2008年 | 97篇 |
2007年 | 103篇 |
2006年 | 88篇 |
2005年 | 85篇 |
2004年 | 79篇 |
2003年 | 73篇 |
2002年 | 58篇 |
2001年 | 46篇 |
2000年 | 43篇 |
1999年 | 44篇 |
1998年 | 33篇 |
1997年 | 35篇 |
1996年 | 44篇 |
1995年 | 54篇 |
1994年 | 49篇 |
1993年 | 44篇 |
1992年 | 41篇 |
1991年 | 29篇 |
1990年 | 36篇 |
1989年 | 28篇 |
1988年 | 29篇 |
1987年 | 30篇 |
1986年 | 44篇 |
1985年 | 43篇 |
1984年 | 27篇 |
1983年 | 16篇 |
1982年 | 29篇 |
1981年 | 21篇 |
1980年 | 32篇 |
1979年 | 29篇 |
1978年 | 24篇 |
1977年 | 20篇 |
1976年 | 24篇 |
1973年 | 17篇 |
1972年 | 20篇 |
排序方式: 共有2875条查询结果,搜索用时 31 毫秒
1.
《Cell》2021,184(25):6138-6156.e28
2.
3.
Larvae and nymphs of the tick Ixodes ricinus L. display similar reactions to analogs of the insect juvenile hormones (methoprene and pyriproxyfen), which induce at both stages juvenalization of the Haller's sense organ regenerates. Similar effects were also described for retinoic acid. Unlike juvenoids, retinoic acid can affect not only regeneration, but also normal development of the Haller's organ and cause changes corresponding to so-called regenerative induction. Amputation of the leg and treatment with retinoic acid do not affect the duration of larval or nymphal development, while juvenoids somewhat accelerate their development. 相似文献
4.
5.
6.
《Animal : an international journal of animal bioscience》2020,14(6):1120-1127
In order to map quantitative trait loci (QTLs) for allometries of body compositions and metabolic traits in chicken, we phenotypically characterize the allometric growths of multiple body components and metabolic traits relative to BWs using joint allometric scaling models and then establish random regression models (RRMs) to fit genetic effects of markers and minor polygenes derived from the pedigree on the allometric scalings. Prior to statistically inferring the QTLs for the allometric scalings by solving the RRMs, the LASSO technique is adopted to rapidly shrink most of marker genetic effects to zero. Computer simulation analysis confirms the reliability and adaptability of the so-called LASSO-RRM mapping method. In the F2 population constructed by multiple families, we formulate two joint allometric scaling models of body compositions and metabolic traits, in which six of nine body compositions are tested as significant, while six of eight metabolic traits are as significant. For body compositions, a total of 14 QTLs, of which 9 dominant, were detected to be associated with the allometric scalings of drumstick, fat, heart, shank, liver and spleen to BWs; while for metabolic traits, a total of 19 QTLs also including 9 dominant be responsible for the allometries of T4, IGFI, IGFII, GLC, INS, IGR to BWs. The detectable QTLs or highly linked markers can be used to regulate relative growths of the body components and metabolic traits to BWs in marker-assisted breeding of chickens. 相似文献
7.
Abstract. Although the oesophageal appendages in the four enchytraeids Enchytrueus crypticus, Fredericia strinta, Buchholzia appendiculata , and Achaeta sp. are quite different from one another in shape and position, their histology and ultrastructure are basically the same. These are intestinal appendages, the lumina of which distally end blind and proximally open into the oesophagus. Almost all of the few cells in their single-layered epithelium have a microvillous, cilia-free border at the apex, facing towards the lumen, and basally comprise an extremely extensive labyrinth. The presence of the latter, composed of very thin cell processes, and of numerous mitochondria identifies the organs as energy-producing and -consuming, transport-active structures. Their possible function as a food-moistening organ or osmoregulatory organ is discussed, and they are compared with other intestinal appendages in enchytraeids and other oligochaetes. 相似文献
8.
9.
10.
M. Zamirul Hussain John C. Belton Rajendra S. Bhatnagar 《In vitro cellular & developmental biology. Plant》1978,14(9):740-745
Organ cultures of newborn rat lungs synthesize and accumulate DNA, RNA, collagen and noncollagenous proteins almost at a linear
rate for at least 5 days. During this period the synthesis of collagen consistently exceeds the synthesis of noncollagenous
proteins in a pattern similar to neonatal lung growth in vivo. Although some morphological characteristics of lung architecture
are distorted after culture, fundamental structural similarities to lungs growing in intact animals are retained. When these
cultures are maintained in atmospheres rich in oxygen, increased collagen synthesis is observed, a response similar to that
of lungs in intact animals exposed to high oxygen concentrations in vivo. Our studies suggest that lung organ cultures may
be a suitable system for investigating the biochemical aspects of lung tissue-environmental interaction.
These studies were supported in parts by NIH Grant HL-19668, a contract (68-03-2005) from the U.S. Environmental Protection
Agency, and grants from the California Lung Association. 相似文献