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   1979篇
  免费   381篇
  国内免费   117篇
  2024年   5篇
  2023年   34篇
  2022年   72篇
  2021年   99篇
  2020年   160篇
  2019年   362篇
  2018年   162篇
  2017年   139篇
  2016年   98篇
  2015年   121篇
  2014年   161篇
  2013年   163篇
  2012年   130篇
  2011年   130篇
  2010年   83篇
  2009年   71篇
  2008年   53篇
  2007年   58篇
  2006年   47篇
  2005年   43篇
  2004年   37篇
  2003年   27篇
  2002年   23篇
  2001年   21篇
  2000年   31篇
  1999年   11篇
  1998年   13篇
  1997年   9篇
  1996年   10篇
  1995年   11篇
  1994年   6篇
  1993年   4篇
  1992年   7篇
  1991年   3篇
  1990年   6篇
  1989年   6篇
  1988年   4篇
  1987年   3篇
  1986年   3篇
  1985年   10篇
  1984年   14篇
  1983年   6篇
  1982年   7篇
  1981年   5篇
  1980年   2篇
  1978年   1篇
  1977年   2篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
排序方式: 共有2477条查询结果,搜索用时 15 毫秒
91.
We describe three new species of Pareuchiloglanis. Based on a comparison of 17 valid species of Pareuchiloglanis, the genus can be divided into two groups contingent on their gill opening size and the anus position. One group, which we call the large gill opening group, has a large gill opening extending to the base of the first pectoral-fin element; the anus is obviously closer to pelvic-fin insertion than the anal-fin origin; this group includes five species distributed in the Red and Pearl Rivers, China. The other group has a small gill opening extending only to the middle base of the pectoral-fin elements; the anus is usually located at the midpoint of the pelvic-fin insertion to the anal-fin origin or slightly behind. This group includes the other 12 species, which are distributed in the Mekong and Yangtze Rivers. The large-gill-opening group can be divided into two sub-groups based on the length of the caudal peduncle. One sub-group has a long caudal-peduncle and the distance from the anal-fin origin to caudal-fin base is greater than distance from the pelvic-fin insertion. This sub-group is only distributed in the Pearl River drainage. Another sub-group has a short caudal peduncle and the distance from the anal-fin origin to the caudal-fin base is typically smaller than the distance from the pelvic-fin insertion. This sub-group is only distributed in the Red River basin of China and Vietnam. The former will be called the large-gill-opening group with long caudal peduncle in the text and only includes one species P. longicauda. During our ongoing taxonomic work of specimens collected from Nanpan-jiang and Beipan-jiang (upper Pearl River drainage in Yunnan, China), some Pareuchiloglanis specimens that had the characters of the large-gill-opening group with long caudal peduncle represent three undescribed species.  相似文献   
92.
Kinesin family member 2C (KIF2C), a substantial mitotic regulator, has been verified to exert a malignant function in several cancers. However, its function in hepatocellular carcinoma (HCC) remains unclear. In this study, the expression profile of KIF2C in HCC was characterized through the dataset from the TCGA and clinical tissue microarrays containing 220 pairs of resected HCC tissues and adjacent nontumor tissues in our hospital. The results indicated that KIF2C was substantially higher expression in tumor tissues than adjacent nontumor tissues. High expression of KIF2C significantly correlated with large tumor (>5.0 cm) (P = .001) and implied a dismal postoperative overall survival (OS) (hazard ratio [HR] = 1.729; P = .002) in our cohort of patients. Gain and loss of function assays displayed that KIF2C promoted HCC cell proliferation, accelerated cell cycle progression, and impeded apoptosis. By bioinformatic tools and mechanistic investigation, we found that KIF2C interacted with various cell-cycle-related proteins and was significantly involved in growth-promoting pathways. KIF2C upregulated PCNA and CDC20 expression. Subsequently, we investigated the regulation of KIF2C by competing endogenous RNA and elucidated that has-miR-6715a-3p was directly bond to the 3′-untranslated region of KIF2C through dual luciferase assays, thereby inhibiting KIF2C expression. Furthermore, the long noncoding RNA GS1-358P8.4 was found to be a candidate of KIF2C for has-miR-6715a-3p binding. HCC patients with high lncRNA-GS1-358P8.4 expression had shorter OS and relapse-free survival compared to those with low expression, which was accordance with the KIF2C. Taken together, KIC2C aggravated HCC progression, it could serve as a prognostic indicator and confer a novel target for clinical treatment.  相似文献   
93.
94.
95.
This study aimed to identify prognostic long noncoding RNAs (lncRNAs) signature for predicting the prognosis of patients with rectal cancer. LncRNA-sequencing data and clinicopathological data of patients with rectal cancer were retrieved from The Cancer Genome Atlas database. Univariate and multivariate Cox proportional hazards regression analysis, the least absolute shrinkage, and selection operator analysis and the Kaplan-Meier curve method were employed to identify prognostic lncRNAs and construct multi-lncRNA signature. Finally, five lncRNAs (AC079789.1, AC106900.2, AL121987.1, AP004609.1, and LINC02163) were identified to construct a five-lncRNA signature. According to the five-lncRNA signature, patients with rectal cancer were divided into a high-risk group and low-risk group. Patients with rectal cancer had significantly poorer overall survival in the high-risk group than in the low-risk group. We used a time-dependent receiver operating characteristic curve to assess the power of the five-lncRNA signature by calculating the area under the curve (AUC). The AUCs for predicting 3-year survival and 5-year survival were 0.742 and 0.935, respectively, which indicated a good performance of the five-lncRNA signature. The five-lncRNA signature was independently associated with the prognosis of patients with rectal cancer through using univariate and multivariate Cox regression analysis. The biological function of the five lncRNAs was enriched in some cancer-related biological processes and pathways by performing functional enrichment analysis of their correlated protein-coding genes. In conclusion, we developed a five-lncRNA signature as a potential indicator for rectal cancer.  相似文献   
96.
Transforming growth factor β (TGFβ) is a prominent cytokine that promotes tumor progression by activating epithelial-to-mesenchymal transition (EMT). This study indicated that TGFβ exerted metastasis by inducing zinc finger E-box binding homeobox 1 (ZEB1) and a long noncoding RNA, LINC00273, expressions in A549 cells. Knocking down LINC00273 diminished TGFβ induced ZEB1 expression as well as metastasis. Mechanistically, LINC00273 acted as a molecular sponge of microRNA (miR)-200a-3p which liberate ZEB1 to perform its prometastatic functions. LINC00273 knockdown and miR200a3p mimic transfection of A549 cells were used for validating the link between TGFβ and LINC00273 induced metastasis. RNA pulldown and luciferase assay were performed to establish mir200a-3p-LINC00273 interaction. High expressions of LINC00273, TGFβ, and ZEB1 with concurrent low miR200a-3p expression had been verified in vivo and in patient samples. Overall, LINC00273 promoted TGFβ-induced lung cancer EMT through miR-200a-3p/ZEB1 feedback loop and may serve as a potential target for therapeutic intervention in lung cancer metastasis.  相似文献   
97.
Gastric cancer is the third leading cause of cancer death with 5-year survival rate of about 30–35%. Since early detection is associated with decreased mortality, identification of novel biomarkers for early diagnosis and proper management of patients with the best response to therapy is urgently needed. Long noncoding RNAs (lncRNAs) due to their high specificity, easy accessibility in a noninvasive manner, as well as their aberrant expression under different pathological and physiological conditions, have received a great attention as potential diagnostic, prognostic, or predictive biomarkers. They may also serve as targets for treating gastric cancer. In this review, we highlighted the role of lncRNAs as tumor suppressors or oncogenes that make them potential biomarkers for the diagnosis and prognosis of gastric cancer. Relatively, lncRNAs such as H19, HOTAIR, UCA1, PVT1, tissue differentiation-inducing nonprotein coding, and LINC00152 could be potential diagnostic and prognostic markers in patients with gastric cancer. Also, the impact of lncRNAs such as ecCEBPA, MLK7-AS1, TUG1, HOXA11-AS, GAPLINC, LEIGC, multidrug resistance-related and upregulated lncRNA, PVT1 on gastric cancer epigenetic and drug resistance as well as their potential as therapeutic targets for personalized medicine was discussed.  相似文献   
98.
Glioblastoma multiforme (GBM) is a highly proliferative cancer with generally poor prognosis and accumulating evidence has highlighted the potential of long noncoding RNAs (lncRNAs) in the biological behaviors of glioma cells. This study focused on the identification of lncRNAs to identify targets for possible GBM prognosis. Microarray expression profiling found that 1,759 lncRNAs and 3,026 messenger RNAs (mRNAs) were upregulated, and 1932s lncRNA and 2,979 mRNAs were downregulated in GBM. Bioinformatics analysis and experimental verification identified TCONS_00020456 (TCON) for further analysis. In situ hybridization, along with immunohistochemical and receiver operating characteristic analysis determined TCON (truncation value = 3.5) as highly sensitive and specific in GBM. Grade IV patients with glioma life span with different lncRNA staining scores were analyzed. TCON staining scores below 3.5 indicated poor prognosis (life span ranging from 0.25 to 7 months), even if the glioma was surgically removed. TCON decreased significantly in GBM, and showed a coexpressional relationship with Smad2 and protein kinase C α (PKCα). Overexpression of TCON reduced the proliferation on one hand and migration, invasion on the other. TCON also inhibited epithelial–mesenchymal transformation and glioma progression in vivo, based on a nude mouse tumorigenicity assay. In addition, we predicted a potential binding site and intersection that microRNAs targeting Smad2, PKCα, and TCON through RACE pretest and bioinformatics analysis. Taken together, TCON, regarded as oncosuppressor, targeting the Smad2/PKCα axis plays a novel role in inhibiting the malignant progression of glioma. Moreover, it also demonstrates that the level of TCON can be used as a prognostic and diagnostic biomarker for GBM.  相似文献   
99.
100.
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