全文获取类型
收费全文 | 1978篇 |
免费 | 227篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 74篇 |
妇产科学 | 103篇 |
基础医学 | 287篇 |
口腔科学 | 24篇 |
临床医学 | 179篇 |
内科学 | 463篇 |
皮肤病学 | 13篇 |
神经病学 | 131篇 |
特种医学 | 201篇 |
外科学 | 216篇 |
综合类 | 43篇 |
一般理论 | 1篇 |
预防医学 | 81篇 |
眼科学 | 29篇 |
药学 | 149篇 |
中国医学 | 14篇 |
肿瘤学 | 226篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 26篇 |
2020年 | 22篇 |
2019年 | 28篇 |
2018年 | 38篇 |
2017年 | 35篇 |
2016年 | 30篇 |
2015年 | 57篇 |
2014年 | 69篇 |
2013年 | 75篇 |
2012年 | 127篇 |
2011年 | 125篇 |
2010年 | 90篇 |
2009年 | 88篇 |
2008年 | 99篇 |
2007年 | 99篇 |
2006年 | 85篇 |
2005年 | 92篇 |
2004年 | 97篇 |
2003年 | 80篇 |
2002年 | 72篇 |
2001年 | 63篇 |
2000年 | 64篇 |
1999年 | 69篇 |
1998年 | 34篇 |
1997年 | 39篇 |
1996年 | 44篇 |
1995年 | 35篇 |
1994年 | 26篇 |
1993年 | 24篇 |
1992年 | 31篇 |
1991年 | 29篇 |
1990年 | 38篇 |
1989年 | 36篇 |
1988年 | 33篇 |
1987年 | 33篇 |
1986年 | 21篇 |
1985年 | 22篇 |
1984年 | 21篇 |
1983年 | 16篇 |
1982年 | 13篇 |
1981年 | 17篇 |
1980年 | 10篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 16篇 |
1976年 | 8篇 |
1972年 | 5篇 |
1971年 | 4篇 |
排序方式: 共有2239条查询结果,搜索用时 31 毫秒
51.
Li M, Pang SYY, Song Y, Kung MHW, Ho S‐L, Sham P‐C. Whole exome sequencing identifies a novel mutation in the transglutaminase 6 gene for spinocerebellar ataxia in a Chinese family. Autosomal dominant spinocerebellar ataxias (SCA) constitute a heterogeneous group of inherited disorders. The transglutaminase 6 (TGM6) gene was recently suggested as a SCA causative gene in Chinese SCA families. In this study, two affected members of a three‐generation Chinese family with SCA characterized by progressive cerebellar ataxia and lower limb pyramidal signs were subjected to whole exome sequencing. Through bioinformatics analysis of the sequence variants in these two individuals, we identified a novel mutation in the TGM6 gene (c.1528G>C) which showed perfect co‐segregation with disease phenotype in all nine members of this family. This finding confirms that mutations in TGM6 gene represent an important cause of SCA in Chinese. This study also shows that whole exome sequencing of a small number of affected individuals, leveraged on bioinformatics analysis, can be an efficient strategy for identifying causative mutations in rare Mendelian disorders. 相似文献
52.
53.
Chen XJ Struzhkin VV Wu Z Somayazulu M Qian J Kung S Christensen AN Zhao Y Cohen RE Mao HK Hemley RJ 《Proceedings of the National Academy of Sciences of the United States of America》2005,102(9):3198-3201
Detailed study of the equation of state, elasticity, and hardness of selected superconducting transition-metal nitrides reveals interesting correlations among their physical properties. Both the bulk modulus and Vickers hardness are found to decrease with increasing zero-pressure volume in NbN, HfN, and ZrN. The computed elastic constants from first principles satisfy c11 > c12 > c44 for NbN, but c11 > c44 > c12 for HfN and ZrN, which are in good agreement with the neutron scattering data. The cubic delta-NbN superconducting phase possesses a bulk modulus of 348 GPa, comparable to that of cubic boron nitride, and a Vickers hardness of 20 GPa, which is close to sapphire. Theoretical calculations for NbN show that all elastic moduli increase monotonically with increasing pressure. These results suggest technological applications of such materials in extreme environments. 相似文献
54.
DNA-directed in vitro synthesis of proteins involved in bacterial transcription and translation. 总被引:9,自引:5,他引:9 下载免费PDF全文
T Zarucki-Schulz C Jerez G Goldberg H F Kung K H Huang N Brot H Weissbach 《Proceedings of the National Academy of Sciences of the United States of America》1979,76(12):6115-6119
The in vitro synthesis of elongation factor (EF)-Tu (tufB), the beta beta' subunits of RNA polymerase, ribosomal proteins L10 and L12 directed by DNA from the transducing phage lambda rifd 18, EF-Tu (tufA), EF-G, and the alpha subunit of RNA polymerase directed by DNA from the transducing phage lambda fus3 has been investigated in a crude and a partially defined protein-synthesizing system. Proteins L10 and L12 are synthesized in the partially defined system almost as well as in the crude system. However, the synthesis of EF-Tu, EF-G, and the alpha and beta beta' subunits of RNA polymerase is far less efficient in the partially defined system. An active fraction that stimulates the synthesis of these latter proteins has been obtained by fractionation of a high-speed supernatant on DEAE-cellulose. Because previous studies showed that this fraction (1 M DEAE salt eluate) contains a protein, called L factor, that stimulates beta-galactosidase synthesis in vitro, L factor was tested for activity. Although L factor stimulates the synthesis of the beta beta' subunits, it has little or no effect on the in vitro synthesis of the other products studied. In the present experiments, the ratio of L12/L10 and of EF-Tu (tufA)/EF-G formed is 4-6. These values are consistent with in vivo results. 相似文献
55.
Targeting oncogenic interleukin‐7 receptor signalling with N‐acetylcysteine in T cell acute lymphoblastic leukaemia 下载免费PDF全文
Marc R. Mansour Casie Reed Amy R. Eisenberg Jen‐Chieh Tseng Jean‐Claude Twizere Sarah Daakour Akinori Yoda Scott J. Rodig Noa Tal Chen Shochat Alla Berezovskaya Daniel J. DeAngelo Stephen E. Sallan David M. Weinstock Shai Izraeli Andrew L. Kung Alex Kentsis A. Thomas Look 《British journal of haematology》2015,168(2):230-238
Activating mutations of the interleukin‐7 receptor (IL7R) occur in approximately 10% of patients with T cell acute lymphoblastic leukaemia (T‐ALL). Most mutations generate a cysteine at the transmembrane domain leading to receptor homodimerization through disulfide bond formation and ligand‐independent activation of STAT5. We hypothesized that the reducing agent N‐acetylcysteine (NAC), a well‐tolerated drug used widely in clinical practice to treat acetaminophen overdose, would reduce disulfide bond formation, and inhibit mutant IL7R‐mediated oncogenic signalling. We found that treatment with NAC disrupted IL7R homodimerization in IL7R‐mutant DND‐41 cells as assessed by non‐reducing Western blot, as well as in a luciferase complementation assay. NAC led to STAT5 dephosphorylation and cell apoptosis at clinically achievable concentrations in DND‐41 cells, and Ba/F3 cells transformed by an IL7R‐mutant construct containing a cysteine insertion. The apoptotic effects of NAC could be rescued in part by a constitutively active allele of STAT5. Despite using doses lower than those tolerated in humans, NAC treatment significantly inhibited the progression of human DND‐41 cells engrafted in immunodeficient mice. Thus, targeting leukaemogenic IL7R homodimerization with NAC offers a potentially effective and feasible therapeutic strategy that warrants testing in patients with T‐ALL. 相似文献
56.
Yi-Chen Lee Yi-Fen Chen Ya-Ling Huang Hsien-Feng Kung Tai-Yuan Chen Yung-Hsiang Tsai 《Yao wu shi pin fen xi = Journal of food and drug analysis.》2016,24(4):762
Ten milkfish dumpling products purchased from retail stores in southern Taiwan were collected to determine the occurrence of biogenic amines, histamine-forming bacteria, and adulteration of pork. This study showed the high contents of aerobic plate count (APC), total coliforms (TC) and Escherichia coli in tested milkfish dumpling samples, whereas the average content of various biogenic amines in all tested samples was < 1.6 mg/100 g (< 0.05 to 1.54 mg/100 g). Three histamine-producing bacterial strains (2 isolates of Raoultella ornithinolytica and 1 isolate of Enterobacter aerogenes) isolated from tested samples produced 276.6 ppm to 561.8 ppm of histamine in trypticase soy broth supplemented with 1.0% L-histidine (TSBH). Assay of multiplex polymerase chain reaction (PCR) revealed that the adulteration rates were 50% (5/10) for pork in milkfish dumplings. In addition, milkfish dumpling stuffing was inoculated with R. ornithinolytica at 5.0 log colony forming units (CFU)/g and stored at various temperatures from 4°C to 37°C to investigate bacterial growth and formation of histamine. The histamine contents quickly increased to higher than 50 mg/100 g in samples stored at 37°C and 25°C within 24 hours and 36 hours, respectively, as well as stored at 15°C within 48 hours. Therefore, bacterial growth and histamine formation were controlled by cold storage of the samples at 4°C. 相似文献
57.
58.
59.