全文获取类型
收费全文 | 715篇 |
免费 | 34篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 8篇 |
2018年 | 9篇 |
2017年 | 11篇 |
2016年 | 11篇 |
2015年 | 17篇 |
2014年 | 29篇 |
2013年 | 40篇 |
2012年 | 54篇 |
2011年 | 50篇 |
2010年 | 32篇 |
2009年 | 36篇 |
2008年 | 42篇 |
2007年 | 46篇 |
2006年 | 34篇 |
2005年 | 39篇 |
2004年 | 40篇 |
2003年 | 40篇 |
2002年 | 41篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 14篇 |
1998年 | 7篇 |
1997年 | 10篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 8篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有749条查询结果,搜索用时 31 毫秒
21.
Masumi Hirabayashi Chihiro Tamura Makoto Sanbo Megumi Kato-Itoh Toshihiro Kobayashi Hiromitsu Nakauchi Shinichi Hochi 《Transgenic research》2013,22(2):411-416
The factors responsible for conferring germline competence in embryonic stem (ES) cell lines remain unidentified. In the present study, rat ES cell lines (n = 17) were established with 3i medium (SU5402, PD0325901, CHIR99021), 2i medium (PD0325901, CHIR99021) or 2iF medium (PD0325901, CHIR99021, forskolin), and their potential for germline transmission to the G1 generation was examined. Rat strains were divided into an albino group (F344, Wistar or CAG/Venus transgenic rats with the Wistar background) or a colored coat group (Brown-Norway, Dark-Agouti, or BLK rats selected from >F3 generations of Wistar × Dark-Agouti rats based on their black coat color). Successful germline transmission was observed in 57 % (4/7), 40 % (2/5) and 100 % (5/5) of the ES cells established with 3i, 2i and 2iF media, respectively. ES cell lines from the homozygous CAG/Venus transgenic rats were established in all three media, but only the lines established with the 2iF medium were germline-competent. Neither coat-color (albino: 64 %, 7/11; colored: 67 %, 4/6) nor gender of the ES cell lines (XX: 67 %, 2/3; XY: 64 %, 9/14) were likely to affect germline transmission. 相似文献
22.
Tokushiro Takaso Yukitoshi Kimoto John N. Owens Masumi Kono Tetsuro Mimura 《Sexual plant reproduction》2013,26(1):17-23
In cycads, spermatozoids are released from pollen tubes and swim in fluid toward the archegonia. The source of this fluid was examined using Cycas revoluta Thunb. ovules placed in culture. Dissected female gametophytes just before fertilization produced copious fluid on their upper surface. The fluid first appeared around the archegonial chamber and then on the inside of the archegonial chamber. When this fluid was applied to dry turgid pollen tubes, they discharged spermatozoids 12 h later. The archegonial neck appeared as two semi-spherical swellings, whereas the four neck cells later became visible and they separated in a schizogenous manner. Many globose particles appear on the top of the archegonial neck cells when the fluid is present. The contents of pollen tubes, spermatozoids and surrounding liquid intermingle with the secreted fluid. The female gametophyte differs in ultrastructure during the stages before and after fluid secretion, the latter showing changes suggestive of fluid secretion from the female gametophyte. 相似文献
23.
Yoshimitsu Yamazaki Kuniaki Hosono 《Bioscience, biotechnology, and biochemistry》2013,77(8):2183-2186
1,2-Bis(methylthiomethyl)ferrocene (3) was oxidized by Corynebacterium equi IFO 3730 to give monosulfoxide 4 in two diastereomeric forms with (1S,2R,SS) and (1S,2R,RS) configurations in a ratio of 4:1, while 1,1′-bis(methylthiomethyl)ferrocene (5) was oxidized by Penicillium frequentans IFO 5692 to (R)-monosulfoxide 6 and then preferentially to (R,R)-bissulfoxide 7. Thus, the bacterial monooxygenase generated specific planar chirality in the metallocenic monosulfoxide, and the fungal enzyme formed C2 symmetry in the bissulfoxide. 相似文献
24.
25.
Practical selection methods for rat and mouse round spermatids without DNA staining by flow cytometric cell sorting
下载免费PDF全文
![点击此处可从《Molecular reproduction and development》网站下载免费的PDF全文](/ch/ext_images/free.gif)
26.
27.
28.
We report here a new strategy for derivatizing peptides and proteins at the N-terminus. To achieve this, a nonnatural amino acid was charged onto a tRNA and then enzymatically transferred to a lysine (Lys) unit at the N-terminus of a peptide or a protein by using L/F-tRNA-protein transferase. By using the chemoenzymatic technique, beta-(2-quinolyl)-L-alanine, p-azido-L-phenylalanine, and p-acetyl-L-phenylalanine were introduced to the N-terminus. The latter two nonnatural amino acids possess bioorthogonal functional groups to which artificial tags can be introduced. Actually, a biotin tag was coupled to the bioorthogonal ketone group of acetylphenylalanine at the N-terminus of a peptide. N-terminal-specific biotinylation and fluorescence derivatization of the bioorthogonal azido-containing protein or peptide was also carried out based on a [3 + 2] cycloaddition. The enzymatic transfer of a nonnatural amino acid to the N-terminus of target peptides or proteins was also successfully achieved in the presence of other peptides or crude protein mixtures. 相似文献
29.