全文获取类型
收费全文 | 11675篇 |
免费 | 1056篇 |
国内免费 | 1164篇 |
专业分类
13895篇 |
出版年
2024年 | 44篇 |
2023年 | 196篇 |
2022年 | 409篇 |
2021年 | 674篇 |
2020年 | 474篇 |
2019年 | 556篇 |
2018年 | 523篇 |
2017年 | 397篇 |
2016年 | 525篇 |
2015年 | 768篇 |
2014年 | 922篇 |
2013年 | 920篇 |
2012年 | 1087篇 |
2011年 | 980篇 |
2010年 | 554篇 |
2009年 | 538篇 |
2008年 | 621篇 |
2007年 | 531篇 |
2006年 | 418篇 |
2005年 | 333篇 |
2004年 | 318篇 |
2003年 | 268篇 |
2002年 | 258篇 |
2001年 | 186篇 |
2000年 | 167篇 |
1999年 | 154篇 |
1998年 | 109篇 |
1997年 | 97篇 |
1996年 | 101篇 |
1995年 | 73篇 |
1994年 | 83篇 |
1993年 | 59篇 |
1992年 | 69篇 |
1991年 | 72篇 |
1990年 | 51篇 |
1989年 | 34篇 |
1988年 | 42篇 |
1987年 | 23篇 |
1986年 | 31篇 |
1985年 | 31篇 |
1984年 | 20篇 |
1983年 | 26篇 |
1982年 | 16篇 |
1980年 | 14篇 |
1979年 | 14篇 |
1977年 | 11篇 |
1975年 | 13篇 |
1974年 | 12篇 |
1973年 | 11篇 |
1970年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Yafei Tian Yongping Zhang Shaoyan Hu Lilan Yao Yijian Zhu Shenglong Qiao Daru Lu Junjie Fan 《Blood and Genomics》2021,664(1):63-67
MYH9-related diseases (MYH9-RD) are a group of autosomal dominant diseases caused by mutations in the MYH9 gene, which are featured by thrombocytopenia, giant platelets and granulocyte cytoplasmic inclusion bodies. MYH9-RD patients generally suffer from bleeding syndromes, progressive kidney disease, deafness, or cataracts. Here, we reported on a case of MYH9-RD. A novel heterozygous mutation of MYH9 (c.2344-2345delGTinsTA, p.T782Y) was discovered by targeted sequencing technology. Immunofluorescence analysis of neutrophils confirmed abnormal aggregation of MYH9 protein. The results of this study should expand the MYH9 gene mutation spectrum and provide reference for subsequent researchers and genetic counseling. 相似文献
22.
Liu Zhenyang Wang Junyu Tong Haibo Wang Xiangyang Zhang Dong Fan Qin 《Neurochemical research》2020,45(7):1614-1625
Neurochemical Research - Glioma is a common invasive cancer with unfavorable prognosis in patients. Long non-coding RNAs (lncRNAs) exert significant functions in carcinogenesis of various cancers... 相似文献
23.
24.
Autophagy is an intracellular degradation process for recycling macromolecules and organelles. It plays important roles in plant development and in response to nutritional demand, stress, and senescence. Organisms from yeast to plants contain many autophagy-associated genes (ATG). In this study, we found that a total of 33 ATG homologues exist in the rice [Oryza sativa L. (Os)] genome, which were classified into 13 ATG subfamilies. Six of them are alternatively spliced genes. Evolutional analysis showed that expansion of 10 OsATG homologues occurred via segmental duplication events and that the occurrence of these OsATG homologues within each subfamily was asynchronous. The Ka/Ks ratios suggested purifying selection for four duplicated OsATG homologues and positive selection for two. Calculating the dates of the duplication events indicated that all duplication events might have occurred after the origin of the grasses, from 21.43 to 66.77 million years ago. Semi-quantitative RT–PCR analysis and mining the digital expression database of rice showed that all 33 OsATG homologues could be detected in at least one cell type of the various tissues under normal or stress growth conditions, but their expression was tightly regulated. The 10 duplicated genes showed expression divergence. The expression of most OsATG homologues was regulated by at least one treatment, including hormones, abiotic and biotic stresses, and nutrient limitation. The identification of OsATG homologues showing constitutive expression or responses to environmental stimuli provides new insights for in-depth characterization of selected genes of importance in rice. 相似文献
25.
26.
27.
Ping Xu Yangxi Zheng Jiujiang Liao Mingyu Hu Yike Yang Baozhen Zhang Mark D. Kilby Huijia Fu Yamin Liu Fumei Zhang Liling Xiong Xiyao Liu Huili Jin Yue Wu Jiayu Huang Tingli Han Li Wen Rufei Gao Yong Fu Xiujun Fan Hongbo Qi Philip N. Baker Chao Tong 《Cell proliferation》2023,56(2)
Pre‐eclampsia (PE) is deemed an ischemia‐induced metabolic disorder of the placenta due to defective invasion of trophoblasts during placentation; thus, the driving role of metabolism in PE pathogenesis is largely ignored. Since trophoblasts undergo substantial glycolysis, this study aimed to investigate its function and regulatory mechanism by AMPK in PE development. Metabolomics analysis of PE placentas was performed by gas chromatography–mass spectrometry (GC–MS). Trophoblast‐specific AMPKα1‐deficient mouse placentas were generated to assess morphology. A mouse PE model was established by Reduced Uterine Perfusion Pressure, and placental AMPK was modulated by nanoparticle‐delivered A769662. Trophoblast glucose uptake was measured by 2‐NBDG and 2‐deoxy‐d‐[3H] glucose uptake assays. Cellular metabolism was investigated by the Seahorse assay and GC–MS.PE complicated trophoblasts are associated with AMPK hyperactivation due not to energy deficiency. Thereafter, AMPK activation during placentation exacerbated PE manifestations but alleviated cell death in the placenta. AMPK activation in trophoblasts contributed to GLUT3 translocation and subsequent glucose metabolism, which were redirected into gluconeogenesis, resulting in deposition of glycogen and accumulation of phosphoenolpyruvate; the latter enhanced viability but compromised trophoblast invasion. However, ablation of AMPK in the mouse placenta resulted in decreased glycogen deposition and structural malformation. These data reveal a novel homeostasis between invasiveness and viability in trophoblasts, which is mechanistically relevant for switching between the ‘go’ and ‘grow’ cellular programs.Pre‐eclampsia (PE) is associated with trophoblast AMPK hyperactivation, presumably due to LKB1 phosphorylation, and glucose uptake is consequently increased via trafficking of GLUT3 from the cytosol to the plasma membrane. Such translocation enhances glycolytic flux and redirects glucose metabolic intermediates into gluconeogenesis, resulting in PEP accumulation, which not only benefits cell survival but also suppresses invasion by repressing MMPs, and thus in turn modulates switching between the ‘go’ and ‘grow’ cellular programs. 相似文献
28.
29.
30.
A reactor consisting of filter-separated two stirred compartments was developed to carry out the conversion of suspension of solid substrate d,l-p-hydroxyphenyl-hydantoin (pHPH) into d-n-carbamoyl-p-hydroxyphenylglycine (d-CpHPG) by immobilized d-hydantoinase (IDH). The immobilized enzyme and substrate suspensions were separated by a 60?μm filter to prevent the IDH from contamination with the insoluble impurities present in the substrate. The poor mass transfer between the two compartments limited the overall enzymatic reaction. It took 180?min for this reactor to accomplish the hydrolysis of 4% (w/v) pHPH. However, it took only 45?min for the reactor without using the filter to separate the two stirred compartments. The performance of the filter-separated reactor was significantly improved by applying pressure swing to the system. The pressure swing was generated by cyclically pressurizing the substrate compartment with nitrogen that caused the solution of the two compartments to flow back and forth through the filter. The reaction time for accomplishing the 4% (w/v) pHPH hydrolysis was reduced to 90?min when the pressure swing was applied with a frequency of 20?cycles/hr. The conversion of pHPH suspension of concentration as high as 15% (w/v) was easily accomplished in this pressure swing operated reactor. The used IDH of this reactor showed the same appearance as the fresh one. On the other hand, the used IDH in conventional stirred tank reactor was fouled with insoluble impurities present in the substrate. 相似文献