全文获取类型
收费全文 | 4307篇 |
免费 | 399篇 |
国内免费 | 267篇 |
专业分类
4973篇 |
出版年
2024年 | 20篇 |
2023年 | 72篇 |
2022年 | 109篇 |
2021年 | 200篇 |
2020年 | 288篇 |
2019年 | 483篇 |
2018年 | 233篇 |
2017年 | 140篇 |
2016年 | 138篇 |
2015年 | 150篇 |
2014年 | 247篇 |
2013年 | 268篇 |
2012年 | 131篇 |
2011年 | 195篇 |
2010年 | 144篇 |
2009年 | 137篇 |
2008年 | 181篇 |
2007年 | 207篇 |
2006年 | 170篇 |
2005年 | 155篇 |
2004年 | 136篇 |
2003年 | 146篇 |
2002年 | 132篇 |
2001年 | 99篇 |
2000年 | 81篇 |
1999年 | 72篇 |
1998年 | 74篇 |
1997年 | 77篇 |
1996年 | 51篇 |
1995年 | 57篇 |
1994年 | 35篇 |
1993年 | 37篇 |
1992年 | 41篇 |
1991年 | 40篇 |
1990年 | 20篇 |
1989年 | 40篇 |
1988年 | 37篇 |
1987年 | 16篇 |
1986年 | 20篇 |
1985年 | 15篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 3篇 |
1978年 | 12篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1971年 | 3篇 |
排序方式: 共有4973条查询结果,搜索用时 15 毫秒
61.
I. A. Catalán † E. Berdalet † M. P. Olivar † C. Roldán † 《Journal of fish biology》2007,70(2):391-405
Six condition indices based on RNA, total soluble protein and two metabolic enzymes [lactate dehydrogenase (LDH) and citrate synthase (CS)] were analysed in muscle tissue of individual larvae, post-flexion reared sea bass Dicentrarchus labrax using DNA and total soluble protein as standards for size. In addition, the effect of 2 days of food deprivation on the cell proliferation rates was assessed. The RNA:DNA best reflected short-term changes in feeding conditions. If standardized by DNA content, LDH activity was a better indicator of condition than any other index but RNA:DNA. Further, the analysis of cell proliferation rates in muscle from 26 day-old larvae proved useful in distinguishing continuously fed larvae from individuals subjected to 2 days of fast. 相似文献
62.
Rapid method of in vitro multiplication of date palm was developed. Shoot tips were cultured on Murashige and Skoog (MS) medium supplemented with 2 mg dm–3 dimethylaminopurine (2iP) + 1 mg dm–3 naphthalene acetic acid (NAA). Shoot buds were proliferated from white nodular cultures on hormone free medium. Shoot bud proliferation strongly enhanced when cultured on MS-medium contained 3 mg dm–3 2iP + 0.5 mg dm–3 NAA. Culturing on full-strength MS medium showed higher multiplication rate compared with half-strength MS medium. Among four concentrations of sucrose used, 30 g dm–3 speeded up the bud proliferation more than 10, 20 and 40 g dm–3. However, the largest shoot buds were observed with 40 g dm–3 sucrose. Solidification of culture media by 1.75 g dm–3
Phytagel showed the highest proliferation rate, but the largest buds were observed with 1 g dm–3
Phytagel. 相似文献
63.
64.
65.
66.
Ai‐Hua Tong Juan Tan Jin‐Hua Zhang Fang‐Jiang Xu Fu‐Yuan Li Chun‐Yu Cao 《Journal of biochemical and molecular toxicology》2019,33(2)
Ring1 and YY1 binding protein (RYBP), a new member of the polycomb group protein family, has been reported to play an important role in various biological processes. Recently, more and more studies have demonstrated an implication of RYBP in cancer development. However, the specific role of RYBP in anaplastic thyroid cancer (ATC) remains unknown. In this study, we investigated for the first time the expression pattern and biological functions of RYBP in ATC. We showed that RYBP was lowly expressed in ATC tissues and cell lines. We also found that overexpression of RYBP inhibited ATC cell proliferation, invasion, and cisplatin resistance. Furthermore, we observed that upregulation of RYBP decreased the phosphorylation of EGFR and ERK1/2 in ATC cells. Taken together, our data indicated that RYBP might be considered as a promising therapeutic target for the treatment of ATC. 相似文献
67.
Young Woo Chun Richard B. Hall Loren C. Stephens 《Plant Cell, Tissue and Organ Culture》1986,5(3):179-185
The in vitro shoot proliferation of Populus alba × P. grandidentata was affected by the medium consistency and shoot density, but not by three sizes of vessels. After 4 weeks of culture, the fresh weight and number of shoots per explant on liquid medium were significantly greater than those on agar-solidified medium. In particular, 3.2 shoots, 7 mm or longer per explant, were produced on liquid medium compared with 1.6 shoots per explant or agar-solidified medium. The fresh weight per explant after 4 weeks of culture on liquid medium and agar-solidified medium were 0.68 and 0.25 g, respectively. Increasing the number of shoots per vessel slowed the growth of the explants as measured by fresh weight and the number of shoots produced. There was little difference in the number of shoots produced between vessels with 1 or 2 shoots per vessel, but there were many fewer shoots produced when 3 shoots were placed in each vessel.Journal Paper No. J-11977 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project 2210. 相似文献
68.
目的观察高表达RORα对二烯丙基二硫(DADS)抑制人胃癌MGC803细胞增殖、迁移与侵袭的影响。方法集落形成实验与流式细胞术检测细胞增殖与细胞周期;细胞划痕和Transwell实验分别检测细胞迁移与侵袭。RT-PCR与Western blot分别检测RORα、MMP-9和TIMP3 mRNA与蛋白表达水平。结果RT-PCR与Western blot检测显示,RORα高表达与DADS处理较对照组与空载体组RORαmRNA与蛋白表达明显上调,DADS+RORα高表达组上调更为显著(P<0.05)。与对照组和空载体组比较,RORα高表达与DADS处理组MMP-9表达下调,TIMP3表达上调,DADS+RORα高表达组改变最为显著。集落形成实验显示,RORα高表达与DADS处理组较对照组与空载体组的集落形成率明显降低。流式细胞术显示,与对照组和空载体组比较,RORα高表达与DADS处理组G2/M期细胞比率明显升高。细胞划痕和Transwell实验显示,RORα高表达与DADS处理组细胞迁移与侵袭能力明显降低。结论RORα高表达可通过上调TIMP3与下调MMP-9促进DADS阻滞MGC803细胞G2/M期和抑制增殖与迁移侵袭。 相似文献
69.
Changkun Huang Huanghao Deng Yinhuai Wang Hongyi Jiang Ran Xu Xuan Zhu Zhichao Huang Xiaokun Zhao 《Journal of cellular and molecular medicine》2019,23(9):6112-6119
In recent years, circular RNAs (circRNAs) have been identified to be essential regulators of various human cancers. However, knowledge of the functions of circRNAs in prostate cancer remains very limited. The correlation between circABCC4 and human cancer is largely unknown. This study aims to investigate the biological functions of circABCC4 in prostate cancer progression and illustrate the underlying mechanism. We found that circABCC4 was remarkably up‐regulated in prostate cancer tissues and cell lines and promoted FOXP4 expression by sponging miR‐1182 in prostate cancer cells. CircABCC4 knockdown markedly suppressed prostate cancer cell proliferation, cell‐cycle progression, migration and invasion in vitro. Furthermore, silencing of the circRNA also delayed tumor growth in vivo. Taken together, our findings indicated that circABCC4 facilitates the malignant behaviour of prostate cancer by promoting FOXP4 expression through sponging of miR‐1182. The circABCC4–miR‐1182‐FOXP4 regulatory loop may be a promising therapeutic target for prostate cancer intervention. 相似文献
70.
Peigang Ji Liang Wang Jinghui Liu Ping Mao Ruichun Li Haitao Jiang Miao Lou Meng Xu Xiao Yu 《Journal of cellular biochemistry》2019,120(3):3259-3267
Ribosomal protein L34 (RPL34), belonging to the L34E family of ribosomal proteins, was reported to be dysregulated in several types of cancers and plays important roles in tumor progression. However, the expression and roles of RPL34 in human glioma remain largely unknown. Thus, the objective of this study was to investigate the expression and role of RPL34 in glioma. We report here that RPL34 is highly expressed in human glioma tissues and cell lines. Knockdown of RPL34 markedly inhibited the proliferation, migration, and invasion, as well as prevented the epithelial-mesenchymal transition phenotype in glioma cells. Further, mechanistic analysis showed that knockdown of RPL34 significantly downregulated the levels of p-JAK and p-STAT3 in glioma cells. Taken together, our findings indicated that knockdown of RPL34 inhibits the proliferation and migration of glioma cells through the inactivation of JAK/STAT3 signaling pathway. Thus, RPL34 may serve as a potential therapeutic target for the treatment of glioma. 相似文献