全文获取类型
收费全文 | 2453篇 |
免费 | 117篇 |
国内免费 | 1篇 |
专业分类
2571篇 |
出版年
2022年 | 10篇 |
2021年 | 24篇 |
2020年 | 9篇 |
2019年 | 10篇 |
2018年 | 36篇 |
2017年 | 29篇 |
2016年 | 34篇 |
2015年 | 76篇 |
2014年 | 83篇 |
2013年 | 150篇 |
2012年 | 133篇 |
2011年 | 141篇 |
2010年 | 84篇 |
2009年 | 93篇 |
2008年 | 149篇 |
2007年 | 156篇 |
2006年 | 123篇 |
2005年 | 143篇 |
2004年 | 147篇 |
2003年 | 154篇 |
2002年 | 165篇 |
2001年 | 46篇 |
2000年 | 27篇 |
1999年 | 47篇 |
1998年 | 37篇 |
1997年 | 31篇 |
1996年 | 21篇 |
1995年 | 24篇 |
1994年 | 28篇 |
1993年 | 23篇 |
1992年 | 33篇 |
1991年 | 23篇 |
1990年 | 18篇 |
1989年 | 25篇 |
1988年 | 28篇 |
1987年 | 13篇 |
1986年 | 12篇 |
1985年 | 17篇 |
1984年 | 23篇 |
1983年 | 13篇 |
1982年 | 18篇 |
1981年 | 19篇 |
1980年 | 16篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1974年 | 5篇 |
1972年 | 8篇 |
1971年 | 8篇 |
1970年 | 7篇 |
1962年 | 5篇 |
排序方式: 共有2571条查询结果,搜索用时 0 毫秒
101.
102.
Zhongwei Zou Masahiko Ishida Feng Li Tomohiro Kakizaki Sho Suzuki Hiroyasu Kitashiba Takeshi Nishio 《PloS one》2013,8(1)
SNP markers for QTL analysis of 4-MTB-GSL contents in radish roots were developed by determining nucleotide sequences of bulked PCR products using a next-generation sequencer. DNA fragments were amplified from two radish lines by multiplex PCR with six primer pairs, and those amplified by 2,880 primer pairs were mixed and sequenced. By assembling sequence data, 1,953 SNPs in 750 DNA fragments, 437 of which have been previously mapped in a linkage map, were identified. A linkage map of nine linkage groups was constructed with 188 markers, and five QTLs were detected in two F2 populations, three of them accounting for more than 50% of the total phenotypic variance being repeatedly detected. In the identified QTL regions, nine SNP markers were newly produced. By synteny analysis of the QTLs regions with Arabidopsis thaliana and Brassica rapa genome sequences, three candidate genes were selected, i.e., RsMAM3 for production of aliphatic glucosinolates linked to GSL-QTL-4, RsIPMDH1 for leucine biosynthesis showing strong co-expression with glucosinolate biosynthesis genes linked to GSL-QTL-2, and RsBCAT4 for branched-chain amino acid aminotransferase linked to GSL-QTL-1. Nucleotide sequences and expression of these genes suggested their possible function in 4MTB-GSL biosynthesis in radish roots. 相似文献
103.
Masahiko Kito Daichi Maeda Yukitsugu Kudo-Asabe Naoki Sato Ie-Ming Shih Tian-Li Wang Masamitsu Tanaka Yukihiro Terada Akiteru Goto 《PloS one》2016,11(6)
There is a growing body of evidence regarding cell competition between normal and mutant mammalian cells, which suggest that it may play a defensive role in the early phase of carcinogenesis. In vitro study in the past has shown that overexpression of vimentin in normal epithelial cells at the contact surface with transformed cells is essential for the cell competition involved in epithelial defense against cancer. In this study, we attempted to examine cell competition in human tissue in vivo by investigating surgically resected human fallopian tubes that contain p53 signatures and serous tubal intraepithelial lesions (STILs), a linear expansion of p53-immunopositive/TP53 mutant tubal epithelial cells that are considered as precursors of pelvic high grade serous carcinoma. Immunofluorescence double staining for p53 and the cell competition marker vimentin was performed in 21 sections of human fallopian tube tissue containing 17 p53 signatures and 4 STILs. The intensities of vimentin expression at the interface between p53-positive cells at the end of the p53 signature/STIL and adjacent p53-negative normal tubal epithelial cells were compared with the background tubal epithelium. As a result, the average vimentin intensity at the interfaces relative to the background intensity was 1.076 (95% CI, 0.9412 – 1.211 for p53 signature and 0.9790 (95% CI, 0.7206 – 1.237) for STIL. Thus, it can be concluded that overexpression of the cell competition marker vimentin are not observed in human tissue with TP53 alterations. 相似文献
104.
105.
106.
Naoko Minatani Mina Waraya Keishi Yamashita Mariko Kikuchi Hideki Ushiku Ken Kojo Akira Ema Hiroshi Nishimiya Yoshimasa Kosaka Hiroshi Katoh Norihiko Sengoku Hirokazu Tanino David Sidransky Masahiko Watanabe 《PloS one》2016,11(1)
Using pharmacological unmasking microarray, we identified promoter DNA methylation of cysteine dioxygenase 1 (CDO1) gene in human cancer. In this study, we assessed the clinicopathological significance of CDO1 methylation in primary breast cancer (BC) with no prior chemotherapy. The CDO1 DNA methylation was quantified by TaqMan methylation specific PCR (Q-MSP) in 7 BC cell lines and 172 primary BC patients with no prior chemotherapy. Promoter DNA of the CDO1 gene was hypermethylated in 6 BC cell lines except SK-BR3, and CDO1 gene expression was all silenced at mRNA level in the 7 BC cell lines. Quantification of CDO1 methylation was developed using Q-MSP, and assessed in primary BC. Among the clinicopathologic factors, CDO1 methylation level was not statistically significantly associated with any prognostic factors. The log-rank plot analysis elucidated that the higher methylation the tumors harbored, the poorer prognosis the patients exhibited. Using the median value of 58.0 as a cut-off one, disease specific survival in BC patients with CDO1 hypermethylation showed significantly poorer prognosis than those with hypomethylation (p = 0.004). Multivariate Cox proportional hazards model identified that CDO1 hypermethylation was prognostic factor as well as Ki-67 and hormone receptor status. The most intriguingly, CDO1 hypermethylation was of robust prognostic relevance in triple negative BC (p = 0.007). Promoter DNA methylation of CDO1 gene was robust prognostic indicator in primary BC patients with no prior chemotherapy. Prognostic relevance of the CDO1 promoter DNA methylation is worthy of being paid attention in triple negative BC cancer. 相似文献
107.
Background & Objectives
Expertise of registered dietitians (RDs) is important for health guidance but has been poorly evaluated. We evaluated the kind of RD expertise that would improve their skills.Design, Setting, Participants, Measurements
This study was a post-hoc analysis of our randomized controlled trial, which compared the weight change between participants using the web-based self-disclosure health support and those using the email health support. Healthy men and women aged 35–64 years with a body mass index (BMI) of > = 24.5 kg/m2 were recruited for this study. We evaluated the relationship of RD expertise indicators including the duration of working as an RD, the experience of health counseling, and membership in the Japan Dietetic Association (JDA) with the weight loss of study participants. The primary endpoint was the change in body weight. Comparison of changes in body weight by the RD expertise indicators was evaluated using analysis of covariance.Results
A total of 175 participants were eligible for analyses. Changes in body weight were significantly greater when they were supported by the RDs in the routine counseling group than when supported by the RDs in the non-routine counseling group (-1.8 kg versus -0.4 kg, fully adjusted P = 0.0089). Duration of working as an RD and JDA membership did not significantly affect changes in body weight.Conclusions
Among some indices of RD experience, the experience of providing routine experience of health counseling was associated with weight loss. 相似文献108.
109.
Takashi Ohnuki Masahiko Ejiri Masaaki Kizuka Mie Fujiwara Takahide Nishi 《Bioorganic & medicinal chemistry letters》2019,29(2):199-203
We herein report a practical one-step glucuronidation method by biotransformation using Streptomyces sp. SANK 60895. This novel direct method of biotransformation has been shown to be more practical and scalable for glucuronidation than previously reported chemical and enzymatic procedures given its simplicity, high β-selectivity, cost-effectiveness, and reproducibility. We applied the present method to the synthesis of acyl glucuronide and hydroxy-β-glucuronide of mycophenolic acid and compound 4, respectively. This method was also shown to be applicable to the N-glucuronidation of various compounds. 相似文献
110.
Naoki Yokokawa Emi Kikuchi‐Uehara Eri Amasawa Hirokazu Sugiyama Masahiko Hirao 《Journal of Industrial Ecology》2019,23(5):1253-1263
This study analyzed the environmental impacts of packaging‐derived changes in food production and consumer behavior to assist packaging designers in making environmentally conscious decisions. Packaging can be functionalized to prevent food loss and waste (FLW), for example, extending the expiration date and apportioning the package size, but it can generate additional environmental impacts from changes in food and packaging production. Previous studies assessed additional impacts from packaging production; however, the effects of packaging functionalization are yet to be connected with food production and consumer behavior. To examine the effect of functionalization on these aspects, we analyzed packaging‐derived changes in food production for milk and cabbage products. The case study compared products with functionalized packaging that permits a longer expiration date or a smaller portion size to their base‐case products. Our results showed that the packaging‐derived changes increased the global warming potential (GWP) of food production more than other processes did. Thus, changes in food production weakened the effectiveness of the packaging functionalization to decrease the GWP. Moreover, the analysis of consumer behavior scenarios showed that consumers’ perception of the expiration date decisively influences the effectiveness of packaging functionalization. When consumers discarded food after the expiration date, provided they consumed in small quantities, the packaging functionalization reduced FLW. From the scenario analysis, we identified appropriate combinations of packaging functionalization and consumer behaviors to effectively decrease total GWP. With our expanded analysis, packaging designers can understand the effectiveness of their decisions on the product life cycle in reducing FLW and environmental impacts. 相似文献