全文获取类型
收费全文 | 2760篇 |
免费 | 232篇 |
国内免费 | 1篇 |
专业分类
2993篇 |
出版年
2024年 | 5篇 |
2023年 | 27篇 |
2022年 | 57篇 |
2021年 | 97篇 |
2020年 | 43篇 |
2019年 | 67篇 |
2018年 | 80篇 |
2017年 | 69篇 |
2016年 | 76篇 |
2015年 | 143篇 |
2014年 | 159篇 |
2013年 | 165篇 |
2012年 | 252篇 |
2011年 | 255篇 |
2010年 | 138篇 |
2009年 | 122篇 |
2008年 | 148篇 |
2007年 | 136篇 |
2006年 | 105篇 |
2005年 | 113篇 |
2004年 | 109篇 |
2003年 | 86篇 |
2002年 | 75篇 |
2001年 | 71篇 |
2000年 | 55篇 |
1999年 | 57篇 |
1998年 | 28篇 |
1997年 | 17篇 |
1996年 | 7篇 |
1995年 | 11篇 |
1994年 | 12篇 |
1993年 | 13篇 |
1992年 | 17篇 |
1991年 | 14篇 |
1990年 | 15篇 |
1989年 | 22篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 12篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 11篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1976年 | 5篇 |
1973年 | 4篇 |
1970年 | 4篇 |
1969年 | 5篇 |
排序方式: 共有2993条查询结果,搜索用时 15 毫秒
61.
A new temperate wood bamboo endemic to Vietnam is described and illustrated as Chimonocalamus bidoupensis N.H.Nghia & V.T.Tran. The new species is similar to C. baviensis in general appearance, but differs by its densely ciliate culms, culm sheaths that are concave at the apex with dense, white hairs on the abaxial surface of the sheath, and perfect florets 7–8 mm long. 相似文献
62.
63.
64.
Sarah Findakly Vikas Daggubati Galo Garcia III Sydney A. LaStella Abrar Choudhury Cecilia Tran Amy Li Pakteema Tong Jason Q. Garcia Natasha Puri Jeremy F. Reiter Libin Xu David R. Raleigh 《The Journal of cell biology》2021,220(1)
Vertebrate Hedgehog signals are transduced through the primary cilium, a specialized lipid microdomain that is required for Smoothened activation. Cilia-associated sterol and oxysterol lipids bind to Smoothened to activate the Hedgehog pathway, but how ciliary lipids are regulated is incompletely understood. Here we identified DHCR7, an enzyme that produces cholesterol, activates the Hedgehog pathway, and localizes near the ciliary base. We found that Hedgehog stimulation negatively regulates DHCR7 activity and removes DHCR7 from the ciliary microenvironment, suggesting that DHCR7 primes cilia for Hedgehog pathway activation. In contrast, we found that Hedgehog stimulation positively regulates the oxysterol synthase CYP7A1, which accumulates near the ciliary base and produces oxysterols that promote Hedgehog signaling in response to pathway activation. Our results reveal that enzymes involved in lipid biosynthesis in the ciliary microenvironment promote Hedgehog signaling, shedding light on how ciliary lipids are established and regulated to transduce Hedgehog signals. 相似文献
65.
Khanh B. Tran Gregory Gimenez Peter Tsai Sharada Kolekar Euan J. Rodger Aniruddha Chatterjee Anower Jabed Jen‐Hsing Shih Wayne R. Joseph Elaine S. Marshall Qian Wang Cristin G. Print Michael R. Eccles Bruce C. Baguley Peter R. Shepherd 《Pigment cell & melanoma research》2021,34(1):136-143
Melanoma is a disease associated with a very high mutation burden and thus the possibility of a diverse range of oncogenic mechanisms that allow it to evade therapeutic interventions and the immune system. Here, we describe the characterization of a panel of 102 cell lines from metastatic melanomas (the NZM lines), including using whole‐exome and RNA sequencing to analyse genetic variants and gene expression changes in a subset of this panel. Lines possessing all major melanoma genotypes were identified, and hierarchical clustering of gene expression profiles revealed four broad subgroups of cell lines. Immunogenotyping identified a range of HLA haplotypes as well as expression of neoantigens and cancer–testis antigens in the lines. Together, these characteristics make the NZM panel a valuable resource for cell‐based, immunological and xenograft studies to better understand the diversity of melanoma biology and the responses of melanoma to therapeutic interventions. 相似文献
66.
Dieu T. X. Nguyen Hung Tran Stefan Schwaiger Hermann Stuppner Stefania Marzocco 《化学与生物多样性》2021,18(1):e2000577
The extract of Elsholtzia ciliata aerial parts was subjected to bio-guided isolation using the intercellular ROS reduction in J774A.1 macrophages to monitor the anti-oxidative activity. Fifteen compounds were isolated from the active fractions including eleven flavonoids (vitexin, pedalin, luteolin-7-O-β-d -glucopyranoside, apigenin-5-O-β-d -glucopyranoside, apigenin-7-O-β-d -glucopyranoside, chrysoeriol-7-O-β-d -glucopyranoside, 7,3′-dimethoxyluteolin-6-O-β-d -glucopyranoside, luteolin, 5,6,4′-trihydroxy-7,3′-dimethoxyflavone, 5-hydroxy-6,7-dimethoxyflavone (compound 13 ), 5-hydroxy-7,8-dimethoxyflavone); three hydroxycinnamic acid derivatives (caffeic acid, 4-(E)-caffeoyl-l -threonic acid, 4-O-(E)-p-coumaroyl-l -threonic acid) and one fatty acid (α-linolenic acid). The biological evaluation of these compounds (10–2.5 μm ) indicated that all of them exerted good antioxidant and anti-inflammatory activities, in particular compound 13 . 相似文献
67.
Tra-My N. Duong Thanh-Van Le Khanh-Linh H. Tran Phuong-Tuyen Nguyen Bich-Phuong T. Nguyen Thu-Anh Nguyen Huong-Lan P. Nguyen Bich-Ngoc T. Nguyen Matthew C. Fisher Johanna Rhodes Guy Marks Greg J. Fox Sharon C.-A. Chen Michael G. Walsh Vanessa R. Barrs Jessica Talbot Catriona L. Halliday Tania C. Sorrell Jeremy N. Day Justin Beardsley 《Environmental microbiology》2021,23(12):7632-7642
Azole-resistant environmental Aspergillus fumigatus presents a threat to public health but the extent of this threat in Southeast Asia is poorly described. We conducted environmental surveillance in the Mekong Delta region of Vietnam, collecting air and ground samples across key land-use types, and determined antifungal susceptibilities of Aspergillus section Fumigati (ASF) isolates and azole concentrations in soils. Of 119 ASF isolates, 55% were resistant (or non-wild type) to itraconazole, 65% to posaconazole and 50% to voriconazole. Azole resistance was more frequent in A. fumigatus sensu stricto isolates (95%) than other ASF species (32%). Resistant isolates and agricultural azole residues were overrepresented in samples from cultivated land. cyp51A gene sequence analysis showed 38/56 resistant A. fumigatus sensu stricto isolates carried known resistance mutations, with TR34/L98H most frequent (34/38). 相似文献
68.
Jessica Cruz de Leon Nicole Scheumann Wandy Beatty Josh R. Beck Johnson Q. Tran Candace Yau Peter J. Bradley Keith Gull Bill Wickstead Naomi S. Morrissette 《Eukaryotic cell》2013,12(7):1009-1019
SAS-6 is required for centriole biogenesis in diverse eukaryotes. Here, we describe a novel family of SAS-6-like (SAS6L) proteins that share an N-terminal domain with SAS-6 but lack coiled-coil tails. SAS6L proteins are found in a subset of eukaryotes that contain SAS-6, including diverse protozoa and green algae. In the apicomplexan parasite Toxoplasma gondii, SAS-6 localizes to the centriole but SAS6L is found above the conoid, an enigmatic tubulin-containing structure found at the apex of a subset of alveolate organisms. Loss of SAS6L causes reduced fitness in Toxoplasma. The Trypanosoma brucei homolog of SAS6L localizes to the basal-plate region, the site in the axoneme where the central-pair microtubules are nucleated. When endogenous SAS6L is overexpressed in Toxoplasma tachyzoites or Trypanosoma trypomastigotes, it forms prominent filaments that extend through the cell cytoplasm, indicating that it retains a capacity to form higher-order structures despite lacking a coiled-coil domain. We conclude that although SAS6L proteins share a conserved domain with SAS-6, they are a functionally distinct family that predates the last common ancestor of eukaryotes. Moreover, the distinct localization of the SAS6L protein in Trypanosoma and Toxoplasma adds weight to the hypothesis that the conoid complex evolved from flagellar components. 相似文献
69.
The goal of these investigations was to measure levels of DNA in the plasma of mice following administration of hepatotoxic agents to induce apoptotic or necrotic cell death and determine any differences in the release of this marker depending upon death pathway. For this purpose, the effects of varying doses of anti-Fas, acetaminophen (APAP) or carbon tetrachloride (CCl4) were assessed in normal mice. Plasma DNA was measured fluorometrically by the dye PicoGreen while lactate dehydrogenase (LDH) and caspase 3, other molecules released with cell injury or death, were measured by enzymatic assays. Histology was used to assess the occurrence of apoptosis or necrosis. Results of these experiments indicate that increased blood DNA levels occurred with all three agents and were highest with anti-Fas and CCl4; caspase 3 levels were much higher with anti-Fas than the other agents. Histological examination confirmed the predominance of apoptotic death with anti-Fas and necrotic death with APAP and CCl4. These results indicate that increased blood DNA is common in hepatotoxic injury and is a feature of both apoptotic and necrotic death. 相似文献
70.