全文获取类型
收费全文 | 2147篇 |
免费 | 128篇 |
国内免费 | 3篇 |
出版年
2023年 | 6篇 |
2022年 | 12篇 |
2021年 | 20篇 |
2020年 | 11篇 |
2019年 | 22篇 |
2018年 | 24篇 |
2017年 | 25篇 |
2016年 | 27篇 |
2015年 | 65篇 |
2014年 | 80篇 |
2013年 | 155篇 |
2012年 | 134篇 |
2011年 | 127篇 |
2010年 | 77篇 |
2009年 | 83篇 |
2008年 | 148篇 |
2007年 | 137篇 |
2006年 | 112篇 |
2005年 | 136篇 |
2004年 | 129篇 |
2003年 | 156篇 |
2002年 | 176篇 |
2001年 | 24篇 |
2000年 | 21篇 |
1999年 | 24篇 |
1998年 | 42篇 |
1997年 | 27篇 |
1996年 | 15篇 |
1995年 | 24篇 |
1994年 | 21篇 |
1993年 | 21篇 |
1992年 | 24篇 |
1991年 | 14篇 |
1990年 | 19篇 |
1989年 | 14篇 |
1988年 | 11篇 |
1987年 | 12篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 13篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 10篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1968年 | 4篇 |
排序方式: 共有2278条查询结果,搜索用时 31 毫秒
91.
Yukie Sato Yoshiaki Tsuda Hironori Sakamoto Martijn Egas Tetsuo Gotoh Yutaka Saito Yan‐Xuan Zhang Jian‐Zhen Lin Jung‐Tai Chao Atsushi Mochizuki 《Ecology and evolution》2019,9(4):1590-1602
When males fight for access to females, such conflict rarely escalates into lethal fight because the risks and costs involved, that is, severe injury or death, are too high. The social spider mite, Stigmaeopsis miscanthi, does exhibit lethal male fights, and this male–male aggressiveness varies among populations. To understand the evolution of lethal fighting, we investigated aggressiveness in 42 populations and phylogenetic relationships in 47 populations along the Japanese archipelago. By analysis of the male weapon morph, a proxy for aggressiveness, we confirmed the existence of a mildly aggressive (ML) form, besides the low aggression (LW) and high aggression (HG) forms reported earlier. To evaluate demographic history of these three forms, we employed the approximate Bayesian computation approach using mtCOI sequences and taking into consideration the postlast glacial expansion history of the host plant, Miscanthus sinensis. As results, hierarchical split models are more likely to explain the observed genetic pattern than admixture models, and the ML form in the subtropical region was considered the ancestral group. The inferred demographic history was consistent with the one reconstructed for the host plant in a previous study. The LW form was split from the ML form during the last glacial period (20,000–40,000 years BP), and subsequently, the HG form was split from the ML form at the end of or after the last glacial period (5,494–10,988 years BP). The results also suggest that the mite invaded Japan more than once, resulting in the present parapatric distribution of LW and HG forms in eastern Japan. 相似文献
92.
Glycosylation is a common post-translational modification of proteins. Although its significance in biological system is well recognized, approaches to analyze carbohydrate function are limited. This is because of difficulty in obtaining homogeneous glycoproteins from natural sources. Due to the progress of the carbohydrate and peptide chemistry, syntheses of various homogeneous glycopeptides and glycoproteins, which are suitable for biological studies, have been achieved by chemical means. In this review, we briefly summarize recent advances in the field of glycopeptide synthesis after 1999. 相似文献
93.
94.
95.
Fukasawa A Nagashima T Aoyama T Fukuda N Matsuda H Ueno T Sugiyama H Nagase H Matsumoto Y 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2007,859(2):272-275
A simple and sensitive high-performance liquid chromatography (HPLC) method utilizing UV detection was developed for the determination of plasma pyrrole (Py)-imidazole (Im) polyamides in rats and applied to the pharmacokinetic study of compounds. After deproteinization of plasma with methanol, Py-Im polyamides were analyzed with a reversed-phase TSK-GEL ODS-80TM (4.6 mmx15.0 cm TOSOH Co., Japan) column maintained at 40 degrees C. The mobile phase solvent A was 0.1% acetic acid and the solvent B was HPLC-grade acetonitrile (0-10 min, A: 100-20%, B: 0-80% linear gradient; 10-15 min, A: 40%, B: 60%). The flow rate was 1.0 ml/min. The detection wavelength was set at 310 nm. The method was used to determine the plasma concentration time profiles of Py-Im polyamides after intravenous injection. 相似文献
96.
Maeda Yoshiaki Kobayashi Ryosuke Watanabe Kahori Yoshino Tomoko Bowler Chris Matsumoto Mitsufumi Tanaka Tsuyoshi 《Marine biotechnology (New York, N.Y.)》2022,24(4):788-800
Marine Biotechnology - Microalgae including diatoms are of interest for environmentally friendly manufacturing such as production of biofuels, chemicals, and materials. The highly oil-accumulating... 相似文献
97.
Takeshi Kikko Daisuke Ishizaki Taiga Yodo Shizuo Aino Kunihiko Kuwamura Haruo Okamoto Morihito Nemoto Kazuki Yoneda Nobuyuki Oue Akihisa Sakai Yasuhiro Fujioka Yoshiaki Kai Takuya Sato Kouji Nakayama 《Journal of fish biology》2019,95(2):668-672
Otolith growth increments in wild-caught alizarin complex one (ALC)-marked honmoroko Gnathopogon caerulescens were examined to verify the veracity of the age determination method in cyprinids. ALC-marked G. caerulescens recaptured from their natural environment had lapilli increment counts outside the ALC ring mark that had formed on a daily basis during the juvenile stage. This apparently being the first direct evidence of daily periodicity of otolith increment formation in wild-caught cyprinids. 相似文献
98.
Goki Tanaka Tomoyuki Yamanaka Yoshiaki Furukawa Naoko Kajimura Kaoru Mitsuoka Nobuyuki Nukina 《生物化学与生物物理学报:疾病的分子基础》2019,1865(6):1410-1420
Synucleinopathies comprise a diverse group of neurodegenerative diseases including Parkinson's disease (PD), dementia with Lewy bodies, and multiple system atrophy. These share a common pathological feature, the deposition of alpha-synuclein (a-syn) in neurons or oligodendroglia. A-syn is highly conserved in vertebrates, but the primary sequence of mouse a-syn differs from that of human at seven positions. However, structural differences of their aggregates remain to be fully characterized. In this study, we found that human and mouse a-syn aggregated in vitro formed morphologically distinct amyloid fibrils exhibiting twisted and straight structures, respectively. Furthermore, we identified different protease-resistant core regions, long and short, in human and mouse a-syn aggregates. Interestingly, among the seven unconserved amino acids, only A53T substitution, one of the familial PD mutations, was responsible for structural conversion to the straight-type. Finally, we checked whether the structural differences are transmissible by seeding and found that human a-syn seeded with A53T aggregates formed straight-type fibrils with short protease-resistant cores. These results suggest that a-syn aggregates form sequence-dependent polymorphic fibrils upon spontaneous aggregation but become seed structure-dependent upon seeding. 相似文献
99.
100.