全文获取类型
收费全文 | 5095篇 |
免费 | 371篇 |
国内免费 | 3篇 |
专业分类
5469篇 |
出版年
2024年 | 6篇 |
2023年 | 25篇 |
2022年 | 68篇 |
2021年 | 93篇 |
2020年 | 76篇 |
2019年 | 97篇 |
2018年 | 148篇 |
2017年 | 110篇 |
2016年 | 176篇 |
2015年 | 257篇 |
2014年 | 330篇 |
2013年 | 360篇 |
2012年 | 465篇 |
2011年 | 449篇 |
2010年 | 277篇 |
2009年 | 251篇 |
2008年 | 317篇 |
2007年 | 317篇 |
2006年 | 248篇 |
2005年 | 234篇 |
2004年 | 251篇 |
2003年 | 193篇 |
2002年 | 164篇 |
2001年 | 102篇 |
2000年 | 104篇 |
1999年 | 69篇 |
1998年 | 27篇 |
1997年 | 30篇 |
1996年 | 20篇 |
1995年 | 19篇 |
1994年 | 17篇 |
1993年 | 11篇 |
1992年 | 19篇 |
1991年 | 24篇 |
1990年 | 18篇 |
1989年 | 10篇 |
1988年 | 13篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1982年 | 5篇 |
1980年 | 5篇 |
1978年 | 3篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1967年 | 3篇 |
排序方式: 共有5469条查询结果,搜索用时 0 毫秒
71.
Man Sub Kim Yesol Bak Yun Sun Park Dong Hun Lee Jung Hee Kim Jeong Woo Kang Hyuk-Hwan Song Sei-Ryang Oh Do Young Yoon 《Cell biology and toxicology》2013,29(4):259-272
Wogonin is a flavonoid compound extracted from Scutellaria baicalensis and is well known as a benzodiazepine receptor ligand with anxiolytic effects. Many recent studies have demonstrated that wogonin modulates angiogenesis, proliferation, invasion, and tumor progress in various cancer tissues. We further explored the mechanism of action of wogonin on cervical cancer cells that contain or lack human papillomavirus (HPV) DNA. Wogonin was cytotoxic to HPV 16 (+) cervical cancer cells, SiHa and CaSki, but not to HPV-negative cells. We demonstrated that wogonin induced apoptosis by suppressing the expressions of the E6 and E7 viral oncogenes in HPV-infected cervical cancer CaSki and SiHa cells. The modulation of p53 and protein retinoblastoma (pRb) were also triggered by the suppression of E6 and E7 expressions. However, p53 was not altered in HPV-negative cervical cancer C33A cells. Moreover, wogonin modulated the mitochondrial membrane potential and the expression of pro- and anti-apoptotic factors such as Bax and Bcl-2. Wogonin also provoked the cleavage of caspase-3, caspase-9, and poly ADP ribose polymerase. After transfection of siRNAs to target E6 and E7, additional restoration of p53 and pRb was not induced, but processing of caspases and PARP was increased compared with wogonin treatment alone. Together, our findings demonstrated that wogonin effectively promotes apoptosis by downregulating E6 and E7 expressions and promoting intrinsic apoptosis in human cervical cancer cells. 相似文献
72.
Hyeng-Il Cheun Kyungjin Kim Sejoung Yoon Won-Ja Lee Woo-Yoon Park Seobo Sim Jae-Ran Yu 《The Korean journal of parasitology》2013,51(3):353-355
There are approximately 20 known species of the genus Cryptosporidium, and among these, 8 infect immunocompetent or immunocompromised humans. C. hominis and C. parvum most commonly infect humans. Differentiating between them is important for evaluating potential sources of infection. We report here the development of a simple and accurate real-time PCR-based restriction fragment length polymorphism (RFLP) method to distinguish between C. parvum and C. hominis. Using the CP2 gene as the target, we found that both Cryptosporidium species yielded 224 bp products. In the subsequent RFLP method using TaqI, 2 bands (99 and 125 bp) specific to C. hominis were detected. Using this method, we detected C. hominis infection in 1 of 21 patients with diarrhea, suggesting that this method could facilitate the detection of C. hominis infections. 相似文献
73.
74.
Choya Yoon Erna A. Van Niekerk Kenneth Henry Tetsuhiro Ishikawa Sumihisa Orita Mark H. Tuszynski W. Marie Campana 《The Journal of biological chemistry》2013,288(37):26557-26568
Low-density lipoprotein receptors (LRPs) are present extensively on cells outside of the nervous system and classically exert roles in lipoprotein metabolism. It has been reported recently that LRP1 activation could phosphorylate the neurotrophin receptor TrkA in PC12 cells and increase neurite outgrowth from developing cerebellar granule cells. These intriguing findings led us to explore the hypothesis that LRP1 activation would activate canonical neurotrophic factor signaling in adult neurons and promote axonal regeneration after spinal cord injury. We now find that treatment of adult rat dorsal root ganglion neurons in vitro with LRP1 agonists (the receptor binding domain of α-2-macroglobulin or the hemopexin domain of matrix metalloproteinase 9) induces TrkC, Akt, and ERK activation; significantly increases neurite outgrowth (p < 0.01); and overcomes myelin inhibition (p < 0.05). These effects require Src family kinase activation, a classic LRP1-mediated Trk transactivator. Moreover, intrathecal infusions of LRP1 agonists significantly enhance sensory axonal sprouting and regeneration after spinal cord injury in rats compared with control-infused animals (p < 0.05). A significant role is established for lipoprotein receptors in sprouting and regeneration after CNS injury, identifying a novel class of therapeutic targets to explore for traumatic neurological disorders. 相似文献
75.
Pramod B. Shinde Ah Reum Han Jaeyong Cho So Ra Lee Yeon Hee Ban Young Ji Yoo Eun Ji Kim Eunji Kim Myoung-Chong Song Je Won Park Dong Gun Lee Yeo Joon Yoon 《Journal of biotechnology》2013
Expression plasmids carrying different deoxysugar biosynthetic gene cassettes and the gene encoding a substrate-flexible glycosyltransferase DesVII were constructed and introduced into Streptomyces venezuelae YJ003 mutant strain bearing a deletion of a desosamine biosynthetic (des) gene cluster. The resulting recombinants produced macrolide antibiotic YC-17 analogs possessing unnatural sugars replacing native d-desosamine. These metabolites were isolated and further purified using chromatographic techniques and their structures were determined as d-quinovosyl-10-deoxymethynolide, l-rhamnosyl-10-deoxymethynolide, l-olivosyl-10-deoxymethynolide, and d-boivinosyl-10-deoxymethynolide on the basis of 1D and 2D NMR and MS analyses and the stereochemistry of sugars was confirmed using coupling constant values and NOE correlations. Their antibacterial activities were evaluated in vitro against erythromycin-susceptible and -resistant Enterococcus faecium and Staphylococcus aureus. Substitution with l-rhamnose displayed better antibacterial activity than parent compound YC-17 containing native sugar d-desosamine. The present study on relationships between chemical structures and antibacterial activities could be useful in generation of novel advanced antibiotics utilizing combinatorial biosynthesis approach. 相似文献
76.
77.
H. S. Yoon Y. K. An J. H. Hwang H. S. Lim W. K. Lee K. H. Han S. H. Lee S. D. Choi 《Zeitschrift fur angewandte Ichthyologie》2013,29(2):468-469
Length–weight relationships were estimated for 14 species belonging to 13 fish families from the Suer River estuary, Korea. These 14 species are: Callionymus valenciennei, Konosirus punctatus, Conger myriaster, Cynoglossus joyneri, Tribolodon hakonensis, Thryssa hamiltonii, Acanthogobius flavimanus, Paratrypauchen microcephalus, Hexagrammos agrammus, Nuchequula nuchalis, Pseudopleuronectes yokohamae, Pennahia argentata, Sillago japonica and Takifugu niphobles. Between April 2009 and January 2010, samples were caught by commercial trawl net at depths of <20 m. Estimates for parameter b of the length–weight relationship (W = aLb) ranged between 2.510 and 3.149. 相似文献
78.
Genetic localization and in vivo characterization of a Monascus azaphilone pigment biosynthetic gene cluster 总被引:1,自引:0,他引:1
79.
Sooyeon Park Jung-Sook Lee Kenu-Chul Lee Jung-Hoon Yoon 《Antonie van Leeuwenhoek》2013,104(1):139-147
80.