全文获取类型
收费全文 | 2462篇 |
免费 | 205篇 |
国内免费 | 4篇 |
出版年
2022年 | 25篇 |
2021年 | 49篇 |
2020年 | 18篇 |
2019年 | 19篇 |
2018年 | 24篇 |
2017年 | 20篇 |
2016年 | 55篇 |
2015年 | 104篇 |
2014年 | 122篇 |
2013年 | 119篇 |
2012年 | 183篇 |
2011年 | 181篇 |
2010年 | 106篇 |
2009年 | 85篇 |
2008年 | 122篇 |
2007年 | 106篇 |
2006年 | 119篇 |
2005年 | 96篇 |
2004年 | 115篇 |
2003年 | 101篇 |
2002年 | 87篇 |
2001年 | 78篇 |
2000年 | 83篇 |
1999年 | 58篇 |
1998年 | 29篇 |
1997年 | 24篇 |
1996年 | 21篇 |
1995年 | 13篇 |
1994年 | 22篇 |
1993年 | 8篇 |
1992年 | 31篇 |
1991年 | 44篇 |
1990年 | 22篇 |
1989年 | 36篇 |
1988年 | 27篇 |
1987年 | 47篇 |
1986年 | 27篇 |
1985年 | 36篇 |
1984年 | 28篇 |
1983年 | 19篇 |
1982年 | 16篇 |
1981年 | 12篇 |
1980年 | 7篇 |
1979年 | 22篇 |
1978年 | 15篇 |
1977年 | 17篇 |
1976年 | 8篇 |
1975年 | 12篇 |
1974年 | 15篇 |
1973年 | 9篇 |
排序方式: 共有2671条查询结果,搜索用时 31 毫秒
201.
Ronghai Cheng Ross Ka-Kit Leung Yao Chen Yidan Pan Yin Tong Zhoufang Li Luwen Ning Xuefeng B. Ling Jiankui He 《PloS one》2015,10(10)
We present Virtual Pharmacist, a web-based platform that takes common types of high-throughput data, namely microarray SNP genotyping data, FASTQ and Variant Call Format (VCF) files as inputs, and reports potential drug responses in terms of efficacy, dosage and toxicity at one glance. Batch submission facilitates multivariate analysis or data mining of targeted groups. Individual analysis consists of a report that is readily comprehensible to patients and practioners who have basic knowledge in pharmacology, a table that summarizes variants and potential affected drug response according to the US Food and Drug Administration pharmacogenomic biomarker labeled drug list and PharmGKB, and visualization of a gene-drug-target network. Group analysis provides the distribution of the variants and potential affected drug response of a target group, a sample-gene variant count table, and a sample-drug count table. Our analysis of genomes from the 1000 Genome Project underlines the potentially differential drug responses among different human populations. Even within the same population, the findings from Watson’s genome highlight the importance of personalized medicine. Virtual Pharmacist can be accessed freely at http://www.sustc-genome.org.cn/vp or installed as a local web server. The codes and documentation are available at the GitHub repository (https://github.com/VirtualPharmacist/vp). Administrators can download the source codes to customize access settings for further development. 相似文献
202.
Ovarian high-grade serous carcinomas (HGSCs) and invasive low-grade serous carcinomas (LGSCs) are considered to be distinct entities. In particular, LGSCs are thought to arise from non-invasive serous borderline ovarian tumors (SBOTs) and show poor responsiveness to conventional chemotherapy. The pro-apoptotic effects of CD40 ligand (CD40L) have been demonstrated in HGSC, though the underlying mechanisms are not fully understood. Conversely, the therapeutic potential of the CD40L-CD40 system has yet to be evaluated in LGSC. We now show that CD40 protein is focally expressed on tumor cells in two of five primary LGSCs compared with no expression in eight primary SBOTs. Treatment with CD40L or agonistic CD40 antibody decreased the viability of LGSC-derived MPSC1 and VOA1312 cells, but not SBOT3.1 cells. Small interfering RNA (siRNA) targeting CD40 was used to show that it is required for these reductions in cell viability. CD40L treatment increased cleaved caspase-3 levels in MPSC1 cells though, surprisingly, neither pan-caspase inhibitor nor caspase-3 siRNA reversed or even attenuated CD40L-induced cell death. In addition, CD40-induced cell death was not affected by knockdown of the mitochondrial proteins apoptosis-inducing factor (AIF) and endonuclease G (EndoG). Interestingly, CD40L-induced cell death was blocked by necrostatin-1, an inhibitor of receptor-interacting protein 1 (RIP1), and attenuated by inhibitors of RIP3 (GSK''872) or MLKL (mixed lineage kinase domain-like; necrosulfonamide). Our results indicate that the upregulation of CD40 may be relatively common in LGSC and that CD40 activation induces RIP1-dependent, necroptosis-like cell death in LGSC cells.Epithelial ovarian cancer accounts for approximately 90% of all ovarian malignancies and is the leading cause of gynecological cancer death in developed countries.1, 2 Recently, differences in molecular alterations and clinicopathological features have established a dualistic model dividing ovarian serous carcinomas into high-grade serous carcinoma (HGSC) and low-grade serous carcinoma (LGSC) subtypes. HGSCs are more common and are thought to develop directly from the ovarian surface epithelium or from serous tubal intra-epithelial carcinomas in the fallopian tube. In contrast, LGSCs are rare and are generally considered to develop from benign serous cystadenomas through serous borderline ovarian tumors (SBOT). SBOTs are slow-growing, non-invasive epithelial neoplasms that have a better prognosis compared with other types of ovarian cancer.3, 4, 5 Our previous studies have shown that the inhibition of p53 or treatment of epidermal growth factor or transforming growth factor-β1 increases SBOT cell invasion by inducing epithelial–mesenchymal transition, which suggests a possible mechanism that mediates the progression from SBOT to LGSC.6, 7, 8, 9 However, many of SBOTs recur as LGSCs that display poor responsiveness to conventional chemotherapy and for which survival rates are <50%.1, 3, 10 Thus, the development of novel, targeted therapeutic strategies is likely required to significantly improve patient survival.CD40, a transmembrane glycoprotein belonging to the tumor necrosis factor receptor superfamily, is expressed by a wide range of cell types including immune, endothelial and epithelial cells. Engagement of CD40 with its ligand, CD40L, has been shown to have important roles in a variety of physiological and pathological processes, especially in immunity.11, 12 In addition, CD40 expression has been demonstrated in several types of cancer, including colon, lung, cervical, bladder and prostate cancer.13 However, reported functions of CD40 in tumor cells vary, with both pro-apoptotic and anti-proliferative effects observed depending on the cellular context.14, 15, 16 Alternatively, some studies have shown that CD40 activation may promote the neoplastic transformation and growth of normal cells.17, 18, 19 Expression of CD40 has been demonstrated in ovarian cancer cell lines and tumor samples, but not in normal ovarian tissue, suggesting that CD40 may have an important role in ovarian tumors.20, 21, 22, 23, 24 Indeed, CD40L-CD40 signaling has been shown to induce growth-inhibitory effects in HGSC cells,20, 21, 23, 24, 25 however, the therapeutic potential of CD40 in LGSC and SBOT has not been evaluated.In the present study, we report for the first time elevated CD40 expression in a significant proportion of LGSCs compared with SBOTs. Moreover, CD40 expression is elevated in LGSC-derived MPSC1 and VOA1312 cells compared with SBOT3.1 cells, and CD40 activation induces cell death via CD40 only in LGSC-derived cells. Neither pan-caspase inhibitor nor caspase-3 small interfering RNA (siRNA) has any effect on CD40L-induced MPSC1 cell death. Moreover, CD40L-induced cell death was unaffected by individual or combined knockdown of the mitochondrial proteins apoptosis-inducing factor (AIF) and endonuclease G (EndoG). Interestingly, our results suggest that receptor-interacting protein 1 (RIP1), RIP3 and MLKL are involved in CD40-induced MPSC1 cell death. These results demonstrate that CD40 induces RIP1-dependent, necroptosis-like cell death in LGSC cells. 相似文献
203.
Efficient high‐throughput biological process characterization: Definitive screening design with the Ambr250 bioreactor system
下载免费PDF全文
![点击此处可从《Biotechnology progress》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The burgeoning pipeline for new biologic drugs has increased the need for high‐throughput process characterization to efficiently use process development resources. Breakthroughs in highly automated and parallelized upstream process development have led to technologies such as the 250‐mL automated mini bioreactor (ambr250?) system. Furthermore, developments in modern design of experiments (DoE) have promoted the use of definitive screening design (DSD) as an efficient method to combine factor screening and characterization. Here we utilize the 24‐bioreactor ambr250? system with 10‐factor DSD to demonstrate a systematic experimental workflow to efficiently characterize an Escherichia coli (E. coli) fermentation process for recombinant protein production. The generated process model is further validated by laboratory‐scale experiments and shows how the strategy is useful for quality by design (QbD) approaches to control strategies for late‐stage characterization. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1388–1395, 2015 相似文献
204.
Chao-Hsuan Chang Ying-Chun Chen Weici Zhang Patrick S. C. Leung M. Eric Gershwin Ya-Hui Chuang 《PloS one》2015,10(3)
Invariant natural killer T (iNKT) cells play complex roles in bridging innate and adaptive immunity by engaging with glycolipid antigens presented by CD1d. Our earlier work suggested that iNKT cells were involved in the initiation of the original loss of tolerance in primary biliary cirrhosis (PBC). To address this issue in more detail and, in particular, to focus on whether iNKT cells activated by a Th2-biasing agonist (2s,3s,4r)-1-O-(α-D-galactopyranosyl)-N-tetracosanoyl-2-amino-1,3,4-nonanetriol (OCH), can influence the development of PBC in a xenobiotic-induced PBC murine model. Groups of mice were treated with either OCH or, as a control, α-galactosylceramide (α-GalCer) and thence serially followed for cytokine production, markers of T cell activation, liver histopathology and anti-mitochondrial antibody responses. Further, additional groups of CD1d deleted mice were similarly studied. Our data indicate that administration of OCH has a dramatic influence with exacerbation of portal inflammation and hepatic fibrosis similar to mice treated with α-GalCer. Further, iNKT cell deficient CD1d knockout mice have decreased inflammatory portal cell infiltrates and reduced anti-mitochondrial antibody responses. We submit that activation of iNKT cells can occur via overlapping and/or promiscuous pathways and highlight the critical role of innate immunity in the natural history of autoimmune cholangitis. These data have implications for humans with PBC and emphasize that therapeutic strategies must focus not only on suppressing adaptive responses, but also innate immunity. 相似文献
205.
Albert Lee Hoi-wai Chua Mariana Chan Patrick W. L. Leung Jasmine W. S. Wong Antonio A. T. Chuh 《PloS one》2015,10(6)
Background
The socioeconomic inequalities in child health continue to widen despite improved economy.Objective
To investigate the correlation between socio-economic factors and health risk behaviors and psychosocial well-being of children in Hong Kong.Hypothesis
The null hypothesis is that for this particular developed region, there exists little or no correlation between social-economic factors and health risk behaviors and psychosocial well-being of children.Design
Cross sectional territory wide survey.Participants
Caregivers of 7,000 children in kindergartens in Hong Kong.Measuring tools
Youth Risk Behavior Surveillance questionnaire, health-related knowledge and hygienic practice questionnaire, and Children Behavior Checklist (CBCL).Results
Children were less likely to have somatic complaints and anxiety/depression as reflected by CBCL scores coming from families of higher income, not being recipients of social assistance, with fathers in employment, and with higher parental education. Children with only mother or father as caretakers had lower odds ratios (ORs) 0.71 (95% CI 0.58-0.89) and 0.53 (95% CI 0.33-0.84) respectively to have the habit of eating breakfast, whilst parental education at post-secondary level and higher family income had higher ORs 1.91 (95% CI 1.31-2.78), and 1.63 (95% CI 1.11-2.39). Fathers unemployed, relatives as main caretakers and living in districts with low median household inome incurred higher ORs, as 1.46 (95% CI 1.10-1.94),1.52 (95% CI 1.27-1.83) and 1.17 (95% CI 1.02-1.34) respectively, of watching television over two hours daily, whilst children with parental education at secondary level or above incurred lower OR 0.33 (95% CI 0.24-0.45). Children with parental education at post-secondary level and higher family income had lower ORs of 0.32 (95% CI 0.48-0.97) and 0.52 (95% CI 0.34-0.79) respectively, with regard to exposing to passive smoking, and reversed for those living in districts with lower median household income, lower family income and recipient of CSSA with ORs 1.24 (95% CI 1.06-1.44) and 1.6 (95% CI 1.09-2.37) respectively.Conclusion
Null hypothesis was not supported. A strong gradient was still found to exist among different socio-economic groups for various health-related behaviors in developed society like Hong Kong. 相似文献206.
207.
Yangbo Sun Chao Qiang Jiang Kar Keung Cheng Wei Sen Zhang Gabriel M. Leung Tai Hing Lam C. Mary Schooling 《PloS one》2015,10(8)
Objective
To examine the adjusted associations of fruit consumption and vegetable consumption with the Framingham score and its components in the non-Western setting of Southern China, considering health status.Method
Linear regression was used to assess the cross-sectional associations of fruit and vegetable consumption with the Framingham score and its components, among 19,518 older Chinese (≥50 years) from the Guangzhou Biobank Cohort Study in Southern China (2003–2006), and whether these differed by health status.Results
The association of fruit consumption with the Framingham score varied by health status (P-value<0.001), but not vegetable consumption (P-value 0.51). Fruit consumption was associated with a lower Framingham score (-0.04 per portions/day, 95% confidence interval (CI) -0.08 to -0.004) among participants in poor health, adjusted for age, sex, recruitment phase, socio-economic position and lifestyle. However, similarly adjusted, fruit consumption was associated with a higher Framingham score (0.05, 95% CI 0.02 to 0.09) among participants in good health, perhaps due to a positive association of fruit consumption with fasting glucose. Similarly adjusted, vegetable consumption was associated with a higher Framingham score (0.03, 95% CI 0.01 to 0.05) among all participants, with no difference by health status.Conclusion
This large study from a non-western setting found that fruit and vegetable consumption was barely associated with the Framingham score, or major CVD risk factors. 相似文献208.
We consider genomic imputation for low-coverage genotyping-by-sequencing data with high levels of missing data. We compensate for this loss of information by utilizing family relationships in multiparental experimental crosses. This nearly quadruples the number of usable markers when applied to a large rice Multiparent Advanced Generation InterCross (MAGIC) study. 相似文献
209.
Yuk?Ming Leung Daniel?A. Holdbrook Thomas?J. Piggot Syma Khalid 《Biophysical journal》2014,107(2):460-468
The multidrug and toxic compound extrusion transporters extrude a wide variety of substrates out of both mammalian and bacterial cells via the electrochemical gradient of protons and cations across the membrane. The substrates transported by these proteins include toxic metabolites and antimicrobial drugs. These proteins contribute to multidrug resistance in both mammalian and bacterial cells and are therefore extremely important from a biomedical perspective. Although specific residues of the protein are known to be responsible for the extrusion of solutes, mechanistic details and indeed structures of all the conformational states remain elusive. Here, we report the first, to our knowledge, simulation study of the recently resolved x-ray structure of the multidrug and toxic compound extrusion transporter, NorM from Neisseria gonorrhoeae (NorM_NG). Multiple, atomistic simulations of the unbound and bound forms of NorM in a phospholipid lipid bilayer allow us to identify the nature of the drug-protein/ion-protein interactions, and secondly determine how these interactions contribute to the conformational rearrangements of the protein. In particular, we identify the molecular rearrangements that occur to enable the Na+ ion to enter the cation-binding cavity even in the presence of a bound drug molecule. These include side chain flipping of a key residue, GLU-261 from pointing toward the central cavity to pointing toward the cation binding side when bound to a Na+ ion. Our simulations also provide support for cation binding in the drug-bound and apo states of NorM_NG. 相似文献
210.