全文获取类型
收费全文 | 12749篇 |
免费 | 940篇 |
国内免费 | 826篇 |
出版年
2024年 | 30篇 |
2023年 | 141篇 |
2022年 | 321篇 |
2021年 | 509篇 |
2020年 | 378篇 |
2019年 | 460篇 |
2018年 | 496篇 |
2017年 | 398篇 |
2016年 | 537篇 |
2015年 | 786篇 |
2014年 | 861篇 |
2013年 | 1030篇 |
2012年 | 1196篇 |
2011年 | 1059篇 |
2010年 | 611篇 |
2009年 | 572篇 |
2008年 | 678篇 |
2007年 | 599篇 |
2006年 | 512篇 |
2005年 | 460篇 |
2004年 | 421篇 |
2003年 | 346篇 |
2002年 | 287篇 |
2001年 | 213篇 |
2000年 | 204篇 |
1999年 | 194篇 |
1998年 | 110篇 |
1997年 | 118篇 |
1996年 | 101篇 |
1995年 | 86篇 |
1994年 | 83篇 |
1993年 | 78篇 |
1992年 | 94篇 |
1991年 | 95篇 |
1990年 | 67篇 |
1989年 | 55篇 |
1988年 | 49篇 |
1987年 | 48篇 |
1986年 | 36篇 |
1985年 | 40篇 |
1984年 | 23篇 |
1983年 | 22篇 |
1982年 | 12篇 |
1981年 | 12篇 |
1979年 | 11篇 |
1978年 | 15篇 |
1975年 | 7篇 |
1974年 | 7篇 |
1972年 | 12篇 |
1971年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Yang Tang Sijia Lu Chao Fang Huan Liu Lidong Dong Haiyang Li Tong Su Shichen Li Lingshuang Wang Qun Cheng Baohui Liu Xiaoya Lin Fanjiang Kong 《Plant biotechnology journal》2023,21(4):782-791
Flowering time is one of important agronomic traits determining the crop yield and affected by high temperature. When facing high ambient temperature, plants often initiate early flowering as an adaptive strategy to escape the stress and ensure successful reproduction. However, here we find opposing ways in the short-day crop soybean to respond to different levels of high temperatures, in which flowering accelerates when temperature changes from 25 to 30 °C, but delays when temperature reaches 35 °C under short day. phyA-E1, possibly photoperiodic pathway, is crucial for 35 °C-mediated late flowering, however, does not contribute to promoting flowering at 30 °C. 30 °C-induced up-regulation of FT2a and FT5a leads to early flowering, independent of E1. Therefore, distinct responsive mechanisms are adopted by soybean when facing different levels of high temperatures for successful flowering and reproduction. 相似文献
82.
A novel operation strategy employing self-generated oscillation to imrpove the performances of bioreactors is proposed and applied to a model system consisting of two continuous stirredtank bioreators (CSTBs) connected in series. It is demonstrated via computation that the performance of the system (in terms of timeaveraged cell concentration) can be greatly enhanced by adopting the proposed strategy. The process concept presented and the results obtained in this paper are expected to have significant implications beyond the bioprocessing industry. 相似文献
83.
Pei Shi Wentao Zhu Jiwei Fu An Liang Ting Zheng Zhilong Wen Xincheng Wu Yuchen Peng Songsong Yuan Xiaoping Wu 《Journal of cellular and molecular medicine》2023,27(21):3326-3338
Acute liver failure (ALF) is an inflammation-mediated hepatocyte death process associated with ferroptosis. Avicularin (AL), a Chinese herbal medicine, exerts anti-inflammatory and antioxidative effects. However, the protective effect of AL and the mechanism on ALF have not been reported. Our in vivo results suggest that AL significantly alleviated lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced hepatic pathological injury, liver enzymes, inflammatory cytokines, reactive oxygen species and iron levels and increased the antioxidant enzyme activities (malondialdehyde and glutathione). Our further in vitro experiments demonstrated that AL suppressed inflammatory response in LPS-stimulated RAW 264.7 cells via blocking the toll-like receptor 4 (TLR4)/myeloid differentiation protein-88 (MyD88)/nuclear factor kappa B (NF-κB) pathway. Moreover, AL attenuated ferroptosis in D-GalN-induced HepG2 cells by activating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1)/glutathione peroxidase 4 (GPX4) pathway. Therefore, AL can alleviate inflammatory response and ferroptosis in LPS/D-GalN-induced ALF, and its protective effects are associated with blocking TLR4/MyD88/NF-κB pathway and activating Nrf2/HO-1/GPX4 pathway. Moreover, AL is a promising therapeutic option for ALF and should be clinically explored. 相似文献
84.
Summary Xanthan fermentations in W/O dispersions performed better than the control in both small flasks and a 6.6-L fermentor. The better bulk mixing and oxygen transfer achieved in the dispersion resulted in a still rising xanthan concentration of 65 g/L, compared with 26 g/L in the control. A phase inversion phenomenon was observed when n-hexadecane recovered from previous runs was used as the oil. 相似文献
85.
86.
87.
本试验以黄瓜和水稻幼苗为材料,研究了光照和黑暗条件下低温对植物叶绿素蛋白质复合体的影响。SDS—PAGE电泳结果表明:5℃及12h 280μmol m~(-2)S~(-1)处理2d,Chl-蛋白质复合体的降解明显大于5℃暗低温处理;低温与光照对P700-CPa_1的影响大于LHCP。叶绿素荧光测定表明;5℃及12h 280μmol m~(-2)s~(-1)的处理对PSⅡ的影响亦大于暗低温处理。由此认为:低温与光对植物叶绿体的PSⅠ和PSⅡ都有明显的影响,其机理可能与常温下高光强引起的光抑制相类似;不同的是低温下中等光强就能引起光抑制。因此,在光照低温下往往加剧植物冷害的发生。 相似文献
88.
乌云伞的解剖学及花粉形态学研究 总被引:3,自引:0,他引:3
八角莲属(Dysosma)是小檗科(Berberidaceae)一个重要属,全国共有7个种,大约分布于北纬23—32°,东经94—122°之间。湖北八角莲属有4个种,其中乌云伞(Dysosma lichuanensis Z. Cheng, sp. nev., ined.)为内定种,是多年生草本,它的形态特征与八角莲(Dysosma 相似文献
89.
90.
Xiaofen Tan Yifan Wen Zhijun Han Xuyang Su Jing Peng Feng Chen Yadong Wang Tianming Wang Changzhong Wang Kelong Ma 《化学与生物多样性》2023,20(2):e202200089