首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2237篇
  免费   216篇
  国内免费   103篇
  2024年   2篇
  2023年   32篇
  2022年   32篇
  2021年   94篇
  2020年   117篇
  2019年   121篇
  2018年   106篇
  2017年   99篇
  2016年   108篇
  2015年   131篇
  2014年   168篇
  2013年   170篇
  2012年   203篇
  2011年   193篇
  2010年   103篇
  2009年   110篇
  2008年   92篇
  2007年   97篇
  2006年   97篇
  2005年   67篇
  2004年   55篇
  2003年   56篇
  2002年   42篇
  2001年   34篇
  2000年   33篇
  1999年   27篇
  1998年   20篇
  1997年   19篇
  1996年   16篇
  1995年   15篇
  1994年   21篇
  1993年   12篇
  1992年   16篇
  1991年   11篇
  1990年   7篇
  1989年   4篇
  1988年   8篇
  1987年   6篇
  1986年   4篇
  1985年   5篇
  1983年   2篇
  1982年   1篇
排序方式: 共有2556条查询结果,搜索用时 15 毫秒
1.
2.
Reading is an important part of our daily life, and rapid responses to emotional words have received a great deal of research interest. Our study employed rapid serial visual presentation to detect the time course of emotional noun processing using event-related potentials. We performed a dual-task experiment, where subjects were required to judge whether a given number was odd or even, and the category into which each emotional noun fit. In terms of P1, we found that there was no negativity bias for emotional nouns. However, emotional nouns elicited larger amplitudes in the N170 component in the left hemisphere than did neutral nouns. This finding indicated that in later processing stages, emotional words can be discriminated from neutral words. Furthermore, positive, negative, and neutral words were different from each other in the late positive complex, indicating that in the third stage, even different emotions can be discerned. Thus, our results indicate that in a three-stage model the latter two stages are more stable and universal.  相似文献   
3.
In this study, the fractionation and distribution of phosphorus (P) in the core sediments of the Shanmei reservoir were investigated by using the chemical extraction method in directions for the first time in order to understand its bio-availability, adsorption characteristics, potential release and environmental significance. The results of the study showed that P in the sediments mainly consisted of inorganic phosphorus (IP) and that IP mainly consisted of non-apatite phosphorus (NAIP). The horizontal and temporal distributions of the P fractions were different from each other, but the vertical distribution was similar, which indicated a trend of stabilization after falling. The content of total phosphorus (TP), IP, organic phosphorus (OP), NAIP, apatite phosphorus (AP), and bio-available phosphorus (BAP) in the sediments during the three seasons ranged from 193.85 to 1664.05 mg·kg?1, 126.90 to 1127.70 mg·kg?1, 43.74 to 669.29 mg·kg?1, 57.62 to 937.07 mg·kg?1, 32.58 to 250.71 mg·kg?1, and 41.06 to 871.82 mg·kg?1, respectively. NAIP contents in the sediments accounted for more than 50% of TP. Using an analysis from three aspects, the eutrophication risk index (ERI) could be used to assess the potential release of P in the sediments, and there was a high release risk of P in the sediments in the Shanmei reservoir.  相似文献   
4.
5.
Colorectal cancer is one of the most common and leading malignancies globally. Long noncoding RNAs (lncRNAs) function as potentially critical regulator in colorectal cancer. LINC01234, a novel lncRNA in tumor biology, regulates the progression of various tumors. However, the tumorigenic mechanism of LINC01234 in colorectal cancer is still unclear. This study was performed with the aim to prospectively investigate clinical significance, effect, and mechanism of lncRNA LINC01234 in colorectal cancer. First, we found that LINC01234, localized in the cytoplasm, was increased in both colorectal cancer cell lines and tissues. Subsequent functional assays suggested LINC01234 knockdown suppressed cell proliferation, migration, and invasion of colorectal cancer cells, while blocked cell cycle and induced cell apoptosis. Moreover, we identified that miR-1284 was target of LINC01234, we further demonstrated a negative correlation with LINC01234 in colorectal cancer tissues and cells. Furthermore, miR-1284 targeted and suppressed tumor necrosis factor receptor–associated factor 6 (TRAF6). Loss-of-function assay revealed that LINC01234 silencing suppressed colorectal cancer progression through inhibition of miR-1284. In vivo subcutaneous xenotransplanted tumor model indicated LINC01234 knockdown inhibited in vivo tumorigenic ability of colorectal cancer via downregulation of TRAF6. Collectively, this study clarified the biological significance of LINC01234/miR-1284/TRAF6 axis in colorectal cancer progression, providing insights into LINC01234 as novel potential therapeutic target for colorectal cancer therapeutic from bench to clinic.  相似文献   
6.
7.
Swallow, John G., Theodore Garland, Jr., Patrick A. Carter,Wen-Zhi Zhan, and Gary C. Sieck. Effects of voluntary activity andgenetic selection on aerobic capacity in house mice(Mus domesticus). J. Appl. Physiol. 84(1): 69-76, 1998.An animal model was developed to study effects on components ofexercise physiology of both "nature" (10 generations of geneticselection for high voluntary activity on running wheels) and"nurture" (7-8 wk of access or no access to running wheels,beginning at weaning). At the end of the experiment, mice from bothwheel-access groups were significantly lighter in body mass than micefrom sedentary groups. Within the wheel-access group, a statisticallysignificant, negative relationship existed between activity and finalbody mass. In measurements of maximum oxygen consumption during forcedtreadmill exercise (O2 max), mice withwheel access were significantly more cooperative than sedentary mice;however, trial quality was not a significant predictor of individualvariation in O2 max.Nested two-way analysis of covariance demonstrated that both geneticselection history and access to wheels had significant positive effects on O2 max.A 12% difference inO2 max existedbetween wheel-access selected mice, which had the highestmass-correctedO2 max, andsedentary control mice, which had the lowest. The respiratory exchangeratio at O2 max wasalso significantly lower in the wheel-access group. Our results suggestthe existence of a possible genetic correlation between voluntaryactivity levels (behavior) and aerobic capacity (physiology).

  相似文献   
8.
Emotional signals are perceived whether or not we are aware of it. The evidence so far mostly came from studies with facial expressions. Here, we investigated whether the pattern of non-conscious face expression perception is found for whole body expressions. Continuous flash suppression (CFS) was used to measure the time for neutral, fearful, and angry facial or bodily expressions to break from suppression. We observed different suppression time patterns for emotions depending on whether the stimuli were faces or bodies. The suppression time for anger was shortest for bodily expressions, but longest for the facial expressions. This pattern indicates different processing and detection mechanisms for faces and bodies outside awareness, and suggests that awareness mechanisms associated with dorsal structures might play a role in becoming conscious of angry bodily expressions.  相似文献   
9.
10.
Oxidized low-density lipoprotein (Ox-LDL)-induced endothelial cell injury plays a crucial role in the pathogenesis of atherosclerosis (AS). Plasma galectin-3 (Gal-3) is elevated inside and drives diverse systemic inflammatory disorders, including cardiovascular diseases. However, the exact role of Gal-3 in ox-LDL-mediated endothelial injury remains unclear. This study explores the effects of Gal-3 on ox-LDL-induced endothelial dysfunction and the underlying molecular mechanisms. In this study, Gal-3, integrin β1, and GTP-RhoA in the blood and plaques of AS patients were examined by ELISA and western blot respectively. Their levels were found to be obviously upregulated compared with non-AS control group. CCK8 assay and flow cytometry analysis showed that Gal-3 significantly decreased cell viability and promoted apoptosis in ox-LDL-treated human umbilical vascular endothelial cells (HUVECs). The upregulation of integrinβ1, GTP-RhoA, p-JNK, p-p65, p-IKKα, and p-IKKβ induced by ox-LDL was further enhanced by treatment with Gal-3. Pretreatment with Gal-3 increased expression of inflammatory factors (interleukin [IL]-6, IL-8, and IL-1β), chemokines(CXCL-1 and CCL-2) and adhesion molecules (VCAM-1 and ICAM-1). Furthermore, the promotional effects of Gal-3 on NF-κB activation and inflammatory factors in ox-LDL-treated HUVECs were reversed by the treatments with integrinβ1-siRNA or the JNK inhibitor. We also found that integrinβ1-siRNA decreased the protein expression of GTP-RhoA and p-JNK, while RhoA inhibitor partially reduced the upregulated expression of p-JNK induced by Gal-3. In conclusion, our finding suggests that Gal-3 exacerbates ox-LDL-mediated endothelial injury by inducing inflammation via integrin β1-RhoA-JNK signaling activation.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号