全文获取类型
收费全文 | 10962篇 |
免费 | 1010篇 |
国内免费 | 444篇 |
出版年
2023年 | 91篇 |
2022年 | 217篇 |
2021年 | 406篇 |
2020年 | 252篇 |
2019年 | 274篇 |
2018年 | 332篇 |
2017年 | 232篇 |
2016年 | 334篇 |
2015年 | 544篇 |
2014年 | 551篇 |
2013年 | 706篇 |
2012年 | 826篇 |
2011年 | 793篇 |
2010年 | 481篇 |
2009年 | 446篇 |
2008年 | 608篇 |
2007年 | 531篇 |
2006年 | 451篇 |
2005年 | 433篇 |
2004年 | 426篇 |
2003年 | 412篇 |
2002年 | 408篇 |
2001年 | 196篇 |
2000年 | 132篇 |
1999年 | 174篇 |
1998年 | 147篇 |
1997年 | 109篇 |
1996年 | 89篇 |
1995年 | 91篇 |
1994年 | 90篇 |
1993年 | 83篇 |
1992年 | 97篇 |
1991年 | 66篇 |
1990年 | 78篇 |
1989年 | 65篇 |
1988年 | 59篇 |
1987年 | 71篇 |
1986年 | 55篇 |
1985年 | 75篇 |
1984年 | 55篇 |
1983年 | 75篇 |
1982年 | 97篇 |
1981年 | 72篇 |
1980年 | 64篇 |
1979年 | 42篇 |
1978年 | 49篇 |
1976年 | 42篇 |
1975年 | 42篇 |
1974年 | 41篇 |
1973年 | 43篇 |
排序方式: 共有10000条查询结果,搜索用时 765 毫秒
21.
22.
23.
Haiyan Miao Jingjing Lu Yibing Guo Hongquan Qiu Yu Zhang Xihao Yao Xiaohong Li Yuhua Lu 《Journal of cellular and molecular medicine》2021,25(7):3654-3664
Pancreatic ductal adenocarcinoma (PDAC) is an invasive and aggressive cancer that remains a major threat to human health across the globe. Despite advances in cancer treatments and diagnosis, the prognosis of PDAC patients remains poor. New and more effective PDAC therapies are therefore urgently required. In this study, we identified a novel host factor, namely the LncRNA TP73-AS1, as overexpressed in PDAC tissues compared to adjacent healthy tissue samples. The overexpression of TP-73-AS1 was found to correlate with both PDAC stage and lymph node metastasis. To reveal its role in PDCA, we targeted TP73-AS1 using LnRNA inhibitors in a range of pancreatic cancer (PC) cell lines. We found that the inhibition of TP73-AS1 led to a loss of MMP14 expression in PC cells and significantly inhibited their migratory and invasive capacity. No effects of TP73-AS1 on cell survival or proliferation were observed. Mechanistically, we found that TP73-AS1 suppressed the expression of the known oncogenic miR-200a. Taken together, these data highlight the prognostic potential of TP73-AS1 for PC patients and highlight it as a potential anti-PDAC therapeutic target. 相似文献
24.
25.
26.
27.
28.
29.
Results were compared between the latex paint and compressed air methods for determining total vessel lengths, and between the sectioning and maceration methods for determining vessel diameters. The minimum, mean, median, and maximum vessel diameters were less with the sectioning method than with the maceration technique. Vessel diameter distributions were always nonnormal and had roughly similar patterns with the two techniques, but were statistically different from one another. In all six species where the paint and air methods for determining vessel length were compared, both methods showed a similar skewed vessel length distribution, with many short vessels and few long ones. Although there was no consistent pattern to the difference in results with these two methods, the vessel length frequency distributions were statistically different from one another. With the paint method, many vessels, especially many of the narrowest ones, were not paint-filled at the paint infusion port. The air method utilized the paint method, in part, and, in addition, is based upon the incorrect assumption that all vessels in the stem are the same diameter. Both techniques tended to exclude vessel lengths of the narrowest vessels. However, the narrow vessels, although numerous, contributed an insignificant amount to the total theoretical hydraulic conductance in stems. 相似文献
30.