全文获取类型
收费全文 | 7060篇 |
免费 | 410篇 |
国内免费 | 20篇 |
专业分类
7490篇 |
出版年
2024年 | 12篇 |
2023年 | 99篇 |
2022年 | 257篇 |
2021年 | 371篇 |
2020年 | 340篇 |
2019年 | 498篇 |
2018年 | 384篇 |
2017年 | 271篇 |
2016年 | 367篇 |
2015年 | 388篇 |
2014年 | 480篇 |
2013年 | 621篇 |
2012年 | 573篇 |
2011年 | 561篇 |
2010年 | 296篇 |
2009年 | 267篇 |
2008年 | 276篇 |
2007年 | 285篇 |
2006年 | 251篇 |
2005年 | 211篇 |
2004年 | 151篇 |
2003年 | 112篇 |
2002年 | 104篇 |
2001年 | 19篇 |
2000年 | 19篇 |
1999年 | 23篇 |
1998年 | 21篇 |
1997年 | 19篇 |
1996年 | 16篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 13篇 |
1992年 | 6篇 |
1991年 | 16篇 |
1990年 | 5篇 |
1989年 | 11篇 |
1988年 | 5篇 |
1987年 | 12篇 |
1986年 | 14篇 |
1985年 | 13篇 |
1984年 | 12篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1977年 | 4篇 |
1974年 | 9篇 |
1973年 | 3篇 |
1966年 | 5篇 |
1962年 | 3篇 |
排序方式: 共有7490条查询结果,搜索用时 17 毫秒
991.
Stuart C. Bogema N. Narasimhachari Mohammad Mumtaz Savely Goldin Robert O. Friedel 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1982,233(1):257-267
A high-performance liquid chromatographic procedure is described for the separation ofcis andtrans isomers of thiothixene, a thioxanthene derivative used as an antipsychotic agent. A radial compression module (RCM-100) was used with both silica and cyanopropyl cartridges. A fixed-wavelength UV detector (254 nm) was used in these studies for quantitation. Mesoridazine is used as an internal standard because of its separation characteristics and reproducible quantitation. C18 Sep-Pak cartridges are used for biological sample cleanup. Plasma samples from patients treated with thiothixene (Navane) were assayed forcis andtrans-thiothixene. Notrans-thiothixene was detectable andcis-thiothixene concentrations ranged from 0 to 22.5 ng/ml. 相似文献
992.
993.
994.
Ensieh Sajadi Sara Dadras Mohammad Bayat Shabnam Abdi Hamid Nazarian Sanaz Ziaeipour Fatemeh Mazini Mahsa Kazemi Mohammad Bagheri Aida Valizadeh Mohammad-Amin Abdollahifar 《Journal of cellular biochemistry》2019,120(10):17312-17325
The current study was conducted to assess the relationship between testicular cells in spermatogenesis, through which the production of healthy and mature sperm is essential. However, it seems necessary to obtain more information about the three-dimensional pattern of the testis cells arrangement, which is directly related to the function of the testis after induction of diabetes. Twelve adult mice (28-30 g) were assigned into two experimental groups: (1) control and (2) diabetic (40 mg/kg STZ). The epididymal sperm collected from the tail of the epididymis and testes samples were taken for stereology, immunocytochemistry and RNA extraction. Our data showed that diabetes could notably decrease the number of testicular cells, together with a reduction of total sperm count. In addition, the results from the second-order stereology indicated the significant changes in the spatial arrangement of Sertoli cells and spermatogonial cells in the diabetic groups, in comparison with the control (P < .05). Moreover, the immunohistochemistry results showed a significant reduction in Sex-determining Region Y (SRY) box 9 gene (SOX9), vimentin, occludin, and connexin-43 positive cells in the diabetic groups compared with the control (P < .05). Furthermore, our data showed that the expression of steroidogenic acute regulatory protein steroidogenic acute regulatory protein (StAR) and peripheral benzodiazepine receptor peripheral benzodiazepine receptor (PBR) was significantly reduced in the diabetic groups, in comparison with the control (P < .05). These findings suggest that structural and functional changes of testis cells after induction of diabetes cause the alterations in the spatial arrangement of Sertoli and spermatogonial cells, ultimately influencing the normal spermatogenesis in mice. 相似文献
995.
Yaghoub Rahimi Amir Mehdizadeh Hojjatollah Nozad Charoudeh Mohammad Nouri Kobra Valaei Shabnam Fayezi Masoud Darabi 《Development, growth & differentiation》2015,57(9):667-674
Stearoyl‐CoA desaturase 1 (SCD1) plays important roles in organ development, glucose tolerance, insulin sensitivity, and cancer. Here, we examined the role of SCD1 for the differentiation of human induced pluripotent stem (hiPS) cells to liver cells by using drug inhibition and biochemical experiments. hiPS cells cultured in a pro‐hepatic medium were exposed to an SCD1 inhibitor at various stages throughout differentiation. Liver‐specific markers, specifically α‐fetoprotein, albumin and urea in conditioned medium, and hepatocyte nuclear factor 4α (HNF4α) and cytochrome P450 7A1 (CYP7A1) gene expressions and triglyceride in cellular extracts were analyzed at various development stages. Measures of hepatocyte‐specific function and triglyceride accumulation in later stages were strongly inhibited a minimum of −29% (P < 0.05) by SCD1 inhibitor in the early stage of hepatic differentiation and effectively reversed (>30%, P < 0.01) by the addition of oleate. The results were also reproducible with human primary mononuclear cells (hPMN). SCD1 inhibitor had no significant effect on liver‐specific markers when it was added in the hepatic maturation stage. However, it strikingly led to higher albumin (1.6‐fold, P = 0.03) and urea (1.9‐fold, P = 0.02) production, and HNF4α (1.9‐fold, P = 0.02) and CYP7A1 (1.3‐fold, P = 0.03) expression upon incubation during the lineage‐commitment stage. Hepatic differentiation from cultured hiPS cells is sensitive to SCD1 inhibition and this sensitivity is affected by the stage of cellular differentiation. Notably, findings also indicate that this notion can be extended to hPMN. The requirement for SCD1 activity in functional differentiation of hepatocytes may have relevance for human liver disease and metabolic dysregulation. 相似文献
996.
997.
998.
Pouria Samadi Saeid Afshar Razieh Amini Rezvan Najafi Ali Mahdavinezhad Abdolazim Sedighi Pashaki Mohammad Hadi Gholami Massoud Saidijam 《Journal of cellular physiology》2019,234(7):10718-10725
Abnormal expression of various microRNAs (miRNAs), as regulators of biological signaling pathways, has a strong association with cancer resistance to chemotherapy and radiotherapy. The let-7 family of miRNAs as tumor suppressors have shown to be downregulated in different types of human malignancies including colorectal cancer (CRC). However, the biological function of let-7 members in the processes of resistance to radiation in CRC has not yet been completely elucidated. Insulin-like growth factor 1 receptor (IGF-1R) signaling pathway is amplified in CRC and leads to its progression, development, and also radiation resistance. So, it seems like an attractive target for anticancer therapy. In this study, by using bioinformatics analysis, it has been revealed that IGF-1R is a direct target of the let-7e member. Consistent with this, we identified that increased levels of let-7e in CRC cells reduced IGF-1R protein level and subsequently its downstream signaling pathways, which resulted in the G1 cell cycle arrest and a significant reduction in the proliferation, survival and also resistance to radiation of CRC cells. Altogether, these results suggested that let-7e by targeting the IGF-1R signaling pathway might serve as therapeutics in anticancer therapy. 相似文献
999.
1000.