全文获取类型
收费全文 | 1452篇 |
免费 | 70篇 |
专业分类
1522篇 |
出版年
2022年 | 7篇 |
2021年 | 11篇 |
2020年 | 11篇 |
2019年 | 4篇 |
2018年 | 23篇 |
2017年 | 13篇 |
2016年 | 22篇 |
2015年 | 34篇 |
2014年 | 46篇 |
2013年 | 92篇 |
2012年 | 58篇 |
2011年 | 82篇 |
2010年 | 51篇 |
2009年 | 58篇 |
2008年 | 101篇 |
2007年 | 88篇 |
2006年 | 98篇 |
2005年 | 100篇 |
2004年 | 105篇 |
2003年 | 94篇 |
2002年 | 101篇 |
2001年 | 10篇 |
2000年 | 13篇 |
1999年 | 17篇 |
1998年 | 22篇 |
1997年 | 19篇 |
1996年 | 20篇 |
1995年 | 21篇 |
1994年 | 34篇 |
1993年 | 21篇 |
1992年 | 12篇 |
1991年 | 8篇 |
1990年 | 13篇 |
1989年 | 12篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 8篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1974年 | 6篇 |
1971年 | 3篇 |
1970年 | 3篇 |
排序方式: 共有1522条查询结果,搜索用时 0 毫秒
141.
Masaki Asada Tetsuo Obitsu Atsushi Kinoshita Yoshihiko Nakai Toshihiko Nagase Isamu Sugimoto Motoyuki Tanaka Hiroya Takizawa Ken Yoshikawa Kazutoyo Sato Masami Narita Shuichi Ohuchida Hisao Nakai Masaaki Toda 《Bioorganic & medicinal chemistry letters》2010,20(8):2639-2643
A series of novel N-acylsulfonamide analogs were synthesized and evaluated for their binding affinity and antagonist activity for the EP3 receptor subtype. Representative compounds were also evaluated for their inhibitory effect on PGE2-induced uterine contraction in pregnant rats. Among those tested, a series of N-acylbenzenesulfonamide analogs were found to be more potent than the corresponding carboxylic acid analogs in both the in vitro and in vivo evaluations. The structure activity relationships (SAR) are also discussed. 相似文献
142.
143.
Nobuhito Hayashimoto Masami Ueno Akira Takakura Toshio Itoh 《Experimental Animals》2006,55(5):487-490
Phylogenetic analysis using the gyrB sequence was performed to investigate the genetic relevance among 49 isolates of P. pneumotropica. In the phylogeny, the isolates were clearly classified into three groups as follows: group A for the isolates of biotype Jawetz derived from mice, group B for the isolates of biotype Jawetz derived from rats, and group C for the isolates of biotype Heyl. These results suggest that the gyrB sequence of P. pneumotropica differs between the isolates of two biotypes, and also between the isolates derived from mice and rats in the biotype Jawetz. 相似文献
144.
Hiroki Obata Noritaka Kawashima Masami Akai Kimitaka Nakazawa Tatsuyuki Ohtsuki 《Journal of electromyography and kinesiology》2010,20(1):55-60
The purpose of this study was to characterize the effects of aging on the stretch reflex in the ankle muscles, and in particular to compare the effects on the ankle dorsi-flexor (tibialis anterior: TA) and the plantar-flexor (soleus: SOL). Stretch reflex responses were elicited in the TA and SOL at rest and during weak voluntary contractions in 20 elderly and 23 young volunteers. The results indicated that, in the TA muscle, the elderly group had a remarkably larger long-latency reflex (LLR), whereas no aging effect was found in the short latency reflex (SLR). These results were very different from those in the SOL muscle, which showed significant aging effects in the SLR and medium latency reflex (MLR), but not in the LLR. Given the fact that the LLR of the TA stretch reflex includes the cortical pathway, it is probable that the effects of aging on the TA stretch reflex involve alterations not only at the spinal level but also at the cortical level. The present results indicate that the stretch reflexes of each of the ankle antagonistic muscles are affected differently by aging, which might have relevance to the neural properties of each muscle. 相似文献
145.
Katayama T Tanaka M Moriizumi J Nakamura T Brouchkov A Douglas TA Fukuda M Tomita F Asano K 《Applied and environmental microbiology》2007,73(7):2360-2363
Phylogenetic analysis of bacteria preserved within an ice wedge from the Fox permafrost tunnel was undertaken by cultivation and molecular techniques. The radiocarbon age of the ice wedge was determined. Our results suggest that the bacteria in the ice wedge adapted to the frozen conditions have survived for 25,000 years. 相似文献
146.
147.
148.
149.
Matsuki Y Ohmura-Hoshino M Goto E Aoki M Mito-Yoshida M Uematsu M Hasegawa T Koseki H Ohara O Nakayama M Toyooka K Matsuoka K Hotta H Yamamoto A Ishido S 《The EMBO journal》2007,26(3):846-854
The presence of post-translational regulation of MHC class II (MHC II) under physiological conditions has been demonstrated recently in dendritic cells (DCs) that potently function as antigen-presenting cells (APCs). Here, we report that MARCH-I, an E3 ubiquitin ligase, plays a pivotal role in the post-translational regulation of MHC II in B cells. MARCH-I expression was particularly high in B cells, and the forced expression of MARCH-I induced the ubiquitination of MHC II. In B cells from MARCH-I-deficient mice (MARCH-I KO), the half-life of surface MHC II was prolonged and the ubiquitinated form of MHC II completely disappeared. In addition, MARCH-I-deficient B cells highly expressed exogenous antigen-loaded MHC II on their surface and showed high ability to present exogenous antigens. These results suggest that the function of MHC II in B cells is regulated through ubiquitination by MARCH-I. 相似文献
150.
He PJ Hirata M Yamauchi N Hashimoto S Hattori MA 《Molecular and cellular biochemistry》2007,302(1-2):111-118
The circadian clock is responsible for the generation of circadian rhythms in hormonal secretion and metabolism. These peripheral
clocks could be reset by various cues in order to adapt to environmental variations. The ovary can be characterized as having
highly dynamic physiology regulated by gonadotropins. Here, we aimed to address the status of circadian clock in the ovary,
and to explore how gonadotropins could regulate clockwork in granulosa cells (GCs). To this end, we mainly utilized the immunohistochemistry,
RT-PCR, and real-time monitoring of gene expression methods. PER1 protein was constantly abundant across the daily cycle in
the GCs of immature ovaries. In contrast, PER1 protein level was obviously cyclic through the circadian cycle in the luteal
cells of pubertal ovaries. In addition, both FSH and LH induced Per1 expression in cultured immature and mature GCs, respectively. The promoter analysis revealed that the Per1 expression was mediated by the cAMP response element binding protein. In cultured transgenic GCs, both FSH and LH also induced
the circadian oscillation of Per2. However, the Per2 oscillation promoted by FSH quickly dampened within only one cycle, whereas the Per2 oscillation promoted by LH was persistently maintained. Collectively, these findings strongly suggest that both FSH and LH
play an important role in regulating circadian clock in the ovary; however, they might exert differential actions on the clockwork
in vivo due to each specific role within ovarian physiology. 相似文献