全文获取类型
收费全文 | 2724篇 |
免费 | 258篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 30篇 |
儿科学 | 86篇 |
妇产科学 | 110篇 |
基础医学 | 332篇 |
口腔科学 | 57篇 |
临床医学 | 269篇 |
内科学 | 907篇 |
皮肤病学 | 36篇 |
神经病学 | 243篇 |
特种医学 | 85篇 |
外科学 | 396篇 |
综合类 | 33篇 |
一般理论 | 1篇 |
预防医学 | 118篇 |
眼科学 | 34篇 |
药学 | 110篇 |
中国医学 | 5篇 |
肿瘤学 | 151篇 |
出版年
2023年 | 18篇 |
2022年 | 23篇 |
2021年 | 67篇 |
2020年 | 22篇 |
2019年 | 42篇 |
2018年 | 59篇 |
2017年 | 58篇 |
2016年 | 65篇 |
2015年 | 59篇 |
2014年 | 87篇 |
2013年 | 93篇 |
2012年 | 152篇 |
2011年 | 153篇 |
2010年 | 100篇 |
2009年 | 110篇 |
2008年 | 154篇 |
2007年 | 166篇 |
2006年 | 172篇 |
2005年 | 147篇 |
2004年 | 140篇 |
2003年 | 154篇 |
2002年 | 126篇 |
2001年 | 42篇 |
2000年 | 64篇 |
1999年 | 51篇 |
1998年 | 17篇 |
1997年 | 22篇 |
1996年 | 24篇 |
1995年 | 30篇 |
1994年 | 14篇 |
1993年 | 17篇 |
1992年 | 42篇 |
1991年 | 34篇 |
1990年 | 27篇 |
1989年 | 30篇 |
1988年 | 26篇 |
1987年 | 26篇 |
1986年 | 23篇 |
1985年 | 19篇 |
1984年 | 24篇 |
1983年 | 19篇 |
1979年 | 24篇 |
1978年 | 23篇 |
1977年 | 22篇 |
1976年 | 17篇 |
1974年 | 21篇 |
1973年 | 21篇 |
1972年 | 20篇 |
1971年 | 16篇 |
1970年 | 14篇 |
排序方式: 共有3003条查询结果,搜索用时 31 毫秒
71.
Loss of tumorigenicity of rat glioblastoma directed by episome-based antisense cDNA transcription of insulin-like growth factor I. 总被引:1,自引:1,他引:1
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
72.
Joseph Ilan Judith Ilan 《Proceedings of the National Academy of Sciences of the United States of America》1973,70(5):1355-1358
Treatment of insect polyribosomes with 1 M KCl released a messenger ribonucleoprotein with a pronounced 16S peak. Phenol extraction resulted in a defined peak of 10S RNA, which was judged as mRNA by the following criteria: it showed specificity for binding to ribosomes, and the formation of initiation complex was dependent on protein initiation factors, GTP, mRNA, and aminoacyl-tRNA. The complex directed protein synthesis upon the addition of elongation factors. mRNA was treated with phosphatase and phosphorylated at the 5'-end with [(32)P]cyanoethylphosphate. [(32)P]mRNA was digested by T1 ribonuclease to completion and chromatographed on DEAE-cellulose. The only fragment with (32)P was 15 nucleotides long; it was treated with pancreatic ribonuclease and fingerprinted. Fractions of AC, AAC, and AAAC were found. Initiation signal AUG or GUG in these mRNAs does not begin immediately at the 5'-end and may be at a distance greater than 15 nucleotides. Alkaline hydrolysis of mRNAs labeled in vivo with [(14)C]adenosine revealed Ap and pppAp. Alkaline hydrolysis of mRNA labeled with (32)P at the 5'-terminus resulted in pAp. Hence, these results suggest that in a heterogeneous population of mRNAs from insects, all start with A and have sequence homology at the 5'-termini. This sequence may reflect the signal for RNA polymerase on the gene or may promote the binding of mRNA to ribosomes. 相似文献
73.
Israeli E Goldin E Shibolet O Klein A Hemed N Engelhardt D Rabbani E Ilan Y 《World journal of gastroenterology : WJG》2005,11(20):3105-3111
AIM: To evaluate safety and possible efficacy of induction of oral immune regulation using colitis extracted proteins(CEP) in Crohn‘s disease (CD) subjects.METHODS: Ten CDs were treated orally with autologous CEP thrice weekly for 16 wk. Subjects were monitored for CDAI and IBDQ. Immune modulatory effect was assessed by T-lymphocyte FACS analysis, CEP-specific IFNγ ELISPOT assay and cytokine levels.RESULTS: Induction of oral immune regulation significantly ameliorated disease activity. All (10/10) subjects had clinical response (CDAI≤70) and 7/10 achieved clinical remission (CDAI≤150). Significant increase in mean IBDQ score was noted (134±9vs 164±12). No treatment-related adverse events were noted. High levels of CEP-specific IFNγ spot forming colonies were detected in five subjects prior to treatment and in all five, a marked decrease was observed. The CD4+/CDS+ lymphocyte ratio and peripheral NKT cell numbers increased significantly, in 7/10 and in 5/10 subjects, respectively. Significant increase in serum IL-10 and IL-4 levels was observed in 7/10 subjects during treatment period.CONCLUSION: Immune regulation via oral administration of CEP is a safe and possibly effective treatment for subjects with moderate CD and may provide means of antigen-specific immune modulation. 相似文献
74.
Increased Efficiency of Exogenous Messenger RNA Translation in a Krebs Ascites Cell Lysate 总被引:9,自引:11,他引:9
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S. Metafora M. Terada L. W. Dow P. A. Marks A. Bank 《Proceedings of the National Academy of Sciences of the United States of America》1972,69(5):1299-1303
Addition of a 0.5 M KCl wash fraction from rabbit reticulocyte ribosomes causes a 3- to 10-fold increase in the extent of translation of natural mRNAs by Krebs-cell lysates. In the presence of the wash fraction, 1 pmol of rabbit or mouse 10S RNA directs the incorporation of 80 pmol of leucine into rabbit globin. The addition of human 10S RNA results in the synthesis of equal amounts of human alpha and beta chains, identified by column chromatography. The stimulation by the wash fraction is almost completely dependent on added mammalian tRNA. In contrast to the wash fraction from rabbit reticulocytes, the wash fraction isolated from Krebs-cell ribosomes is inhibitory to both endogenous and exogenous mRNA translation. The stimulation by the wash fraction from rabbit ribosomes is not specific for globin mRNAs, but also increases endogenous, phage Qbeta, and viral RNA-directed protein synthesis. 相似文献
75.
31P NMR study of improvement in oxidative phosphorylation by vitamins K3 and C in a patient with a defect in electron transport at complex III in skeletal muscle. 总被引:3,自引:3,他引:3
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S Eleff N G Kennaway N R Buist V M Darley-Usmar R A Capaldi W J Bank B Chance 《Proceedings of the National Academy of Sciences of the United States of America》1984,81(11):3529-3533
The bioenergetic capacity of skeletal muscle in a 17-year-old patient with a severe defect in complex III of the electron transport chain has been examined by 31P NMR measurements of the molar ratio of phosphocreatine to inorganic phosphate (PCr/Pi). Resting ratios were 1.3-2.5, which can be compared with roughly 8.6 for a young, normal female control at rest. Quantitative evaluation of the activity of oxidative metabolism was afforded by the rate of recovery of PCr/Pi from exercise and was found to be 2.5% of normal. After administration of menadione and ascorbate, we found a 21-fold increase of the recovery rate relative to the pretherapy value, to within 56% of the recovery rate of the young female control. Thus, NMR examinations of skeletal muscle at rest and in recovery from activity document marked improvement to specific drug therapy in the electron transport capabilities and the ATP synthesis rate of a patient with a deficiency in a cytochrome b-containing complex III. Improvements in functional ability, although not as dramatic as biochemical changes, are also apparent. 相似文献
76.
Efrat Hadi MD Ilan Bruchim MD Ilana Helman MD Itshak Shehtman MD Rodica Stackievicz MD Ronnie Tepper MD Reli Hershkovitz MD 《Journal of clinical ultrasound : JCU》2015,43(1):59-63
Uterine lymphoma is rare and tends to be misdiagnosed due to lack of specific radiologic features. Few reports have been published on the sonographic characteristics of uterine lymphoma. We present a case report of uterine lymphoma manifested by a fast growing uterus and describe the sonographic findings. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound, 43 :59–63, 2015 相似文献
77.
Marco A. O. Magalhaes Jonathan C. Irish Ilan Weinreb Bayardo Perez-Ordonez 《Head and neck pathology》2015,9(1):114-118
Adenosquamous carcinomas of the head and neck (ADSCs) are rare locally aggressive malignancies characterized by the presence of two distinctive components, a squamous cell carcinoma and an adenocarcinoma. The immunophenotype of the glandular component of ADSCs has only been rarely studied but has been reported as being positive for keratin 7 (CK7) and carcinoembryonic antigen (CEA) and negative for keratin 20 (CK20). Herein, we report a case of an ADSCs of the hypopharynx composed of a superficial squamous cell carcinoma and an adenocarcinoma with an intestinal phenotype. The patient was a 62 year-old male with a T2 N0 M0 squamous cell carcinoma (SCC) of uvula and palate and a T1 N0 M0 of right hypopharynx. The ADSCs of the hypopharynx was composed of a minimally invasive SCC and an adenocarcinoma with tubulo-glandular and cribriform architecture. The neoplastic glands were positive for CK7, CK20, CDX2, CEA and Villin. The patient underwent radiotherapy to both tumors and remains well with no evidence of recurrent disease 19 months after treatment. To the best of our knowledge, this is the first report of an ADSCs of the head and neck with an intestinal phenotype in its glandular component. 相似文献
78.
79.
80.
Avivit Cahn MD Itamar Raz MD Marc Bonaca MD Ofri Mosenzon MD Sabina A. Murphy MPH Ilan Yanuv MSc Aliza Rozenberg MA John P. H. Wilding MD Deepak L. Bhatt MD Darren K. McGuire MD Ingrid A. M. Gause-Nilsson MD Martin Fredriksson MD Peter A. Johansson MSc Gyorgy Jermendy MD Samy Hadjadj MD Anna Maria Langkilde MD Marc S. Sabatine MD Stephen D. Wiviott MD Lawrence A. Leiter MD 《Diabetes, obesity & metabolism》2020,22(8):1357-1368