全文获取类型
收费全文 | 1536篇 |
免费 | 114篇 |
专业分类
1650篇 |
出版年
2023年 | 3篇 |
2022年 | 19篇 |
2021年 | 32篇 |
2020年 | 19篇 |
2019年 | 19篇 |
2018年 | 42篇 |
2017年 | 44篇 |
2016年 | 45篇 |
2015年 | 63篇 |
2014年 | 71篇 |
2013年 | 211篇 |
2012年 | 93篇 |
2011年 | 106篇 |
2010年 | 69篇 |
2009年 | 50篇 |
2008年 | 95篇 |
2007年 | 95篇 |
2006年 | 63篇 |
2005年 | 63篇 |
2004年 | 86篇 |
2003年 | 66篇 |
2002年 | 71篇 |
2001年 | 18篇 |
2000年 | 13篇 |
1999年 | 17篇 |
1998年 | 22篇 |
1997年 | 7篇 |
1996年 | 19篇 |
1995年 | 17篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1982年 | 4篇 |
1980年 | 7篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1969年 | 3篇 |
1907年 | 2篇 |
1906年 | 2篇 |
1905年 | 2篇 |
1904年 | 2篇 |
排序方式: 共有1650条查询结果,搜索用时 15 毫秒
71.
Takao Senda Wei Yu Toshio Okabe Nakaba Sugimoto Morihiro Matsuda 《The Histochemical journal》1998,30(5):331-338
The subcellular localization in anterior pituitary secretory cells of annexin II, one of the Ca2+-dependent phospholipid-binding proteins, was examined by immunohistochemistry and immunoelectron microscopy. Annexin II was associated with the plasma membrane, the membranes of secretory granules and cytoplasmic organelles, such as rough endoplasmic reticulum, mitochondria and vesicles, and with the nuclear envelope. Annexin II was frequently detected at the contact sites of secretory granules with other granules and with the plasma membrane. The anterior pituitary and adrenal medulla were treated with Clostridium perfringens enterotoxin, which induces Ca2+ influx, and examined under an electron microscope. The anterior pituitary cells showed multigranular exocytosis, i.e. multiple fusions of secretory granules with each other and with the plasma membrane, but adrenal chromaffin cells, which lack annexin II on the granule membranes, never showed granule--granule fusion and only single granule exocytosis. From these results, we conclude that, in anterior pituitary secretory cells, annexin II is involved in granule--granule fusion in addition to granule--plasma membrane fusion. © 1998 Chapman & Hall 相似文献
72.
M. Senda Y. Onodera T. Mikami 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(6-7):964-968
The mitochondrial atpA gene sequence of the normal fertile sugarbeet (cv ‘TK81-0’) exists in one full-length version and one truncated version,
both of which are present in normal stoichiometry and have a 406-bp segment in common. The PCR approach as well as prolonged
exposure of Southern blots indicates that the products of the recombination across the 406-bp repeat are present in substoichiometric
amounts in the ‘TK81-0’ genome. Intriguingly, one of these substoichiometric sequence arrangements was revealed to be preferentially
amplified in an evolutionary lineage that led to a cytoplasmic male-sterile variant [I-12CMS(2)] in wild beets. We also found
the 406-bp repeat to be part of a 6.5-kb repeat in the mitochondrial genome of I-12CMS(2). This 6.5-kb duplication is likely
to involve recombination between two sets of repeats (the above-mentioned 406-bp repeat and a 7-bp repeat) in an ancestral
beet mitochondria.
Received: 4 October 1997 / Accepted: 31 October 1997 相似文献
73.
A Bacillus subtilis gene-encoding protein homologous to eukaryotic SMC motor protein is necessary for chromosome partition 总被引:7,自引:6,他引:1
Shigeki Moriya Eitoku Tsujikawa Anwarul K. M. Hassan Kei Asai Takeko Kodama & Naotake Ogasawara 《Molecular microbiology》1998,29(1):179-187
We have analysed the function of a gene of Bacillus subtilis , the product of which shows significant homology with eukaryotic SMC proteins essential for chromosome condensation and segregation. Two mutant strains were constructed; in one, the expression was under the control of the inducible spac promoter (conditional null) and, in the other, the gene was disrupted by insertion (disrupted null). Both could form colonies at 23°C but not at 37°C in the absence of the expression of the Smc protein, indicating that the B. subtilis smc gene was essential for cell growth at higher temperatures. Microscopic examination revealed the formation of anucleate and elongated cells and diffusion of nucleoids within the elongated cells in the disrupted null mutant grown at 23°C and in the conditional null mutant grown in low concentrations of IPTG at 37°C. In addition, immunofluorescence microscopy showed that subcellular localization of the Spo0J partition protein was irregular in the smc disrupted null mutant, compared with bipolar localization in wild-type cells. These results indicate that the B. subtilis smc gene is essential for chromosome partition. The role of B. subtilis Smc protein in chromosome partition is discussed. 相似文献
74.
75.
76.
Maki Kiso Kyoko Shinya Masayuki Shimojima Ryo Takano Kei Takahashi Hiroaki Katsura Satoshi Kakugawa Mai thi Quynh Le Makoto Yamashita Yousuke Furuta Makoto Ozawa Yoshihiro Kawaoka 《PLoS pathogens》2010,6(8)
Influenza viruses resistant to antiviral drugs emerge frequently. Not surprisingly, the widespread treatment in many countries of patients infected with 2009 pandemic influenza A (H1N1) viruses with the neuraminidase (NA) inhibitors oseltamivir and zanamivir has led to the emergence of pandemic strains resistant to these drugs. Sporadic cases of pandemic influenza have been associated with mutant viruses possessing a histidine-to-tyrosine substitution at position 274 (H274Y) in the NA, a mutation known to be responsible for oseltamivir resistance. Here, we characterized in vitro and in vivo properties of two pairs of oseltaimivir-sensitive and -resistant (possessing the NA H274Y substitution) 2009 H1N1 pandemic viruses isolated in different parts of the world. An in vitro NA inhibition assay confirmed that the NA H274Y substitution confers oseltamivir resistance to 2009 H1N1 pandemic viruses. In mouse lungs, we found no significant difference in replication between oseltamivir-sensitive and -resistant viruses. In the lungs of mice treated with oseltamivir or even zanamivir, 2009 H1N1 pandemic viruses with the NA H274Y substitution replicated efficiently. Pathological analysis revealed that the pathogenicities of the oseltamivir-resistant viruses were comparable to those of their oseltamivir-sensitive counterparts in ferrets. Further, the oseltamivir-resistant viruses transmitted between ferrets as efficiently as their oseltamivir-sensitive counterparts. Collectively, these data indicate that oseltamivir-resistant 2009 H1N1 pandemic viruses with the NA H274Y substitution were comparable to their oseltamivir-sensitive counterparts in their pathogenicity and transmissibility in animal models. Our findings highlight the possibility that NA H274Y-possessing oseltamivir-resistant 2009 H1N1 pandemic viruses could supersede oseltamivir-sensitive viruses, as occurred with seasonal H1N1 viruses. 相似文献
77.
Haskell Andrew; Nadel Ethan R.; Stachenfeld Nina S.; Nagashima Kei; Mack Gary W. 《Journal of applied physiology》1997,83(2):407-413
Haskell, Andrew, Ethan R. Nadel, Nina S. Stachenfeld, KeiNagashima, and Gary W. Mack. Transcapillary escape rate of albuminin humans during exercise-induced hypervolemia. J. Appl. Physiol. 83(2): 407-413, 1997.To test thehypotheses that plasma volume (PV) expansion 24 h after intenseexercise is associated with reduced transcapillary escape rate ofalbumin (TERalb) and that localchanges in transcapillary forces in the previously active tissues favorretention of protein in the vascular space, we measured PV,TERalb, plasma colloid osmoticpressure (COPp), interstitialfluid hydrostatic pressure (Pi), and colloid osmotic pressure in legmuscle and skin and capillary filtration coefficient (CFC) in the armand leg in seven men and women before and 24 h after intense uprightcycle ergometer exercise. Exercise expanded PV by 6.4% at 24 h (43.9 ± 0.8 to 46.8 ± 1.2 ml/kg, P < 0.05) and decreased total protein concentration (6.5 ± 0.1 to6.3 ± 0.1 g/dl, P < 0.05) andCOPp (26.1 ± 0.8 to 24.3 ± 0.9 mmHg, P < 0.05), although plasmaalbumin concentration was unchanged. TERalb tended to decline (8.4 ± 0.5 to 6.5 ± 0.7%/h, P = 0.11) and was correlated with the increase in PV(r = 0.69,P < 0.05). CFC increased in the leg(3.2 ± 0.2 to 4.3 ± 0.5 µl · 100 g1 · min1 · mmHg1,P < 0.05), and Pi showed a trend toincrease in the leg muscle (2.8 ± 0.7 to 3.8 ± 0.3 mmHg, P = 0.08). These datademonstrate that TERalb isassociated with PV regulation and that local transcapillary forcesin the leg muscle may favor retention of albumin in the vascular spaceafter exercise. 相似文献
78.
79.
Satoshi Komoto Ratana Tacharoenmuang Ratigorn Guntapong Tomihiko Ide Kei Haga Kazuhiko Katayama Takema Kato Yuya Ouchi Hiroki Kurahashi Takao Tsuji Somchai Sangkitporn Koki Taniguchi 《PloS one》2015,10(11)
The emergence and rapid spread of unusual DS-1-like G1P[8] rotaviruses in Japan have been recently reported. During rotavirus surveillance in Thailand, three DS-1-like G1P[8] strains (RVA/Human-wt/THA/PCB-180/2013/G1P[8], RVA/Human-wt/THA/SKT-109/2013/G1P[8], and RVA/Human-wt/THA/SSKT-41/2013/G1P[8]) were identified in stool specimens from hospitalized children with severe diarrhea. In this study, we sequenced and characterized the complete genomes of strains PCB-180, SKT-109, and SSKT-41. On whole genomic analysis, all three strains exhibited a unique genotype constellation including both genogroup 1 and 2 genes: G1-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2. This novel genotype constellation is shared with Japanese DS-1-like G1P[8] strains. Phylogenetic analysis revealed that the G/P genes of strains PCB-180, SKT-109, and SSKT-41 appeared to have originated from human Wa-like G1P[8] strains. On the other hand, the non-G/P genes of the three strains were assumed to have originated from human DS-1-like strains. Thus, strains PCB-180, SKT-109, and SSKT-41 appeared to be derived through reassortment event(s) between Wa-like G1P[8] and DS-1-like human rotaviruses. Furthermore, strains PCB-180, SKT-109, and SSKT-41 were found to have the 11-segment genome almost indistinguishable from one another in their nucleotide sequences and phylogenetic lineages, indicating the derivation of the three strains from a common origin. Moreover, all the 11 genes of the three strains were closely related to those of Japanese DS-1-like G1P[8] strains. Therefore, DS-1-like G1P[8] strains that have emerged in Thailand and Japan were assumed to have originated from a recent common ancestor. To our knowledge, this is the first report on whole genome-based characterization of DS-1-like G1P[8] strains that have emerged in an area other than Japan. Our observations will provide important insights into the evolutionary dynamics of emerging DS-1-like G1P[8] rotaviruses. 相似文献
80.
Shingo Noguchi Hiroshi Mukae Toshinori Kawanami Kei Yamasaki Kazumasa Fukuda Kentarou Akata Hiroshi Ishimoto Hatsumi Taniguchi Kazuhiro Yatera 《PloS one》2015,10(4)