全文获取类型
收费全文 | 12006篇 |
免费 | 1133篇 |
国内免费 | 690篇 |
专业分类
耳鼻咽喉 | 200篇 |
儿科学 | 188篇 |
妇产科学 | 163篇 |
基础医学 | 1695篇 |
口腔科学 | 108篇 |
临床医学 | 1528篇 |
内科学 | 2016篇 |
皮肤病学 | 131篇 |
神经病学 | 654篇 |
特种医学 | 422篇 |
外国民族医学 | 9篇 |
外科学 | 1262篇 |
综合类 | 1497篇 |
一般理论 | 1篇 |
预防医学 | 581篇 |
眼科学 | 315篇 |
药学 | 1168篇 |
8篇 | |
中国医学 | 549篇 |
肿瘤学 | 1334篇 |
出版年
2024年 | 21篇 |
2023年 | 170篇 |
2022年 | 391篇 |
2021年 | 565篇 |
2020年 | 430篇 |
2019年 | 440篇 |
2018年 | 432篇 |
2017年 | 358篇 |
2016年 | 368篇 |
2015年 | 578篇 |
2014年 | 696篇 |
2013年 | 666篇 |
2012年 | 901篇 |
2011年 | 926篇 |
2010年 | 581篇 |
2009年 | 481篇 |
2008年 | 586篇 |
2007年 | 597篇 |
2006年 | 604篇 |
2005年 | 572篇 |
2004年 | 389篇 |
2003年 | 370篇 |
2002年 | 332篇 |
2001年 | 250篇 |
2000年 | 291篇 |
1999年 | 322篇 |
1998年 | 174篇 |
1997年 | 195篇 |
1996年 | 175篇 |
1995年 | 139篇 |
1994年 | 128篇 |
1993年 | 84篇 |
1992年 | 105篇 |
1991年 | 65篇 |
1990年 | 67篇 |
1989年 | 63篇 |
1988年 | 47篇 |
1987年 | 47篇 |
1986年 | 44篇 |
1985年 | 23篇 |
1984年 | 26篇 |
1983年 | 25篇 |
1982年 | 12篇 |
1981年 | 14篇 |
1979年 | 8篇 |
1978年 | 6篇 |
1977年 | 11篇 |
1976年 | 10篇 |
1974年 | 7篇 |
1971年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 437 毫秒
91.
Chloe Miu Mak Ching-Wan Lam Sidney Tam Ching-Lung Lai Lik-Yuen Chan Sheung-Tat Fan Yu-Lung Lau Sik-To Lai Patrick Yuen Joannie Hui Chun-Cheung Fu Ka-Sing Wong Wing-Lai Mak Kong Tze Sui-Fan Tong Abby Lau Nancy Leung Aric Hui Ka-Ming Cheung Chun-Hung Ko Yiu-Ki Chan Oliver Ma Tai-Nin Chau Alexander Chiu Yan-Wo Chan 《Journal of human genetics》2008,53(4):375-375
92.
Mayne M Moffatt T Kong H McLaren PJ Fowke KR Becker KG Namaka M Schenck A Bardoni B Bernstein CN Melanson M 《European journal of immunology》2004,34(4):1217-1227
DNA microarray profiling of CD4(+) and CD8(+) cells from non-treated relapsing and remitting multiple sclerosis (MS) patients determined that the cytoplasmic binding partner of fragile X protein (CYFIP2, also called PIR121) was increased significantly compared to healthy controls. Western analysis confirmed that CYFIP2 protein was increased approximately fourfold in CD4(+) cells from MS compared to inflammatory bowel disorder (IBD) patients or healthy controls. Because CYFIP2 acts as part of a tetrameric complex that regulates WAVE1 activation we hypothesized that high levels of CYFIP2 facilitate T cell adhesion, which is elevated in MS patients. Several findings indicated that increased levels of CYFIP2 facilitated adhesion. First, adenoviral-mediated overexpression of CYFIP2 in Jurkat cells increased fibronectin-mediated adhesion. Secondly, CYFIP2 knock-down experiments using antisense oligodeoxynucleotides reduced fibronectin-mediated binding in Jurkat and CD4(+) cells. Thirdly, inhibition of Rac-1, a physical partner with CYFIP2 and regulator of WAVE1 activity, reduced fibronectin-mediated adhesion in Jurkat and CD4(+) cells. Finally, inhibition of Rac-1 or reduction of CYFIP2 protein decreased fibronectin-mediated adhesion in CD4(+) cells from MS patients to levels similar to controls. These studies suggest that overabundance of CYFIP2 protein facilitates increased adhesion properties of T cells from MS patients. 相似文献
93.
The increased incidence of thyroid carcinomas in familial adenomatous polyposis (FAP) patients is well recognised. These thyroid neoplasms display distinctive clinicopathological features and generally show good prognostic outcome. Recently, unusual sporadic tumours that share the morphological features of FAP-associated thyroid carcinomas have also been described. In this report, we document a case of a thyroid tumour in a previously well, 46-year-old female. Histology revealed a circumscribed neoplasm composed of tubular, papillary, cribriform and solid areas. The pseudostratified columnar tumour cells showed occasional nuclear grooves and rare nuclear inclusions. Immunohistochemistry showed positive staining with antibodies to cytokeratin AE1/AE3, oestrogen and progesterone receptor proteins. Focal immunoreactivity was also noted with antibodies to thyroglobulin, epithelial membrane antigen, 34betaE12 and cytokeratin CK7. The absence of polyps on colonoscopy and germline mutation in the adenomatous polyposis coli (APC) gene provides evidence that this tumour represents the sporadic counterpart of FAP-associated thyroid carcinoma. The patient is well with no evidence of disease 7 months following resection of the tumour. The differential diagnoses and molecular genetics of this unusual tumour are discussed. 相似文献
94.
兔心窦房结的亚微结构观察 总被引:5,自引:2,他引:5
本文观查了8例杂种成免心脏窦房结的亚微结构。窦房结主要由P细胞和T细胞构成。P细胞多成团存在。细胞圆形或多边形,胞核大,可见双核细胞;胞质内肌原纤维和线粒体较少;核糖体、糖原颗粒、高尔基氏器、粗面和滑面内质网均较丰富;高尔基氏器附近有电子密度较高的球形颗粒;胞膜下见到许多小凹和小囊;P细胞间有散在的中间连接。T细胞的形态和结构介于P细胞和心肌细胞之间。最后对窦房结内各细胞的功能特点加以讨论。 相似文献
95.
抗T细胞单克隆抗体对再生障碍性贫血患者TNF和IL—2水平的影响 总被引:2,自引:0,他引:2
为探讨抗T淋巴细胞克隆抗体对再生障碍性贫血患者免疫功能的调节作用,采用放射免疫检测25例AA患者McAb-T治疗前后血清肿瘤坏死因子和白细胞介素-2(IL-2)水平及其中10例周围血单个核细胞体外诱生TNF和IL-2水平的变化。 相似文献
96.
Sequences at the 3'-ends of both positive and negative strands of Hepatitis C virus (HCV) RNA harbor cis-acting elements required for RNA replication. However, little is known about the properties of the negative RNA strand as a template for the synthesis of positive RNA strand. In this study, a purified recombinant HCV RNA-dependent RNA polymerase (RdRp) was used to investigate the synthesis of positive RNA strand using the 3'-terminal region of negative RNA strand ((-)3'T RNA) as template. A mutagenesis analysis was performed to evaluate the role of the 3'-proximal stem-loop and the first 3'-cytidylate (3'C) of the negative RNA strand in the synthesis of the positive RNA strand. A negative RNA strand of wild type (wt) HCV as template was able to direct the synthesis of a full-length positive RNA strand. Deletion of the 3'-proximal stem-loop resulted in an approximately 90% decrease in RNA synthesis. Disruption of the 3'-proximal stem-loop structure by nucleotide substitutions led to a 70-80% decrease in RNA synthesis. However, the restoration of the stem-loop by compensatory mutations in the stem region restored also the RNA synthesis. Likewise, the deletion or substitution of the first 3'C by guanylate (G) led to a 90% decrease in the RNA synthesis; while the substitution by adenylate (A) or uridylate (U) resulted in a 60-80% decrease in the RNA synthesis only. These findings demonstrate that the 3'-proximal stem-loop and the first 3'C of the negative RNA strand of HCV are two cis-acting elements involved in the synthesis of the positive RNA strand. 相似文献
97.
本文采用放射性同位素标记的方法研究了嵌段聚醚型聚氨酯在纯纤维蛋白原溶液中和稀释血浆中的表面纤维蛋白原吸附性规律,考察了聚醚型聚氨酯的特性粘数及溶液体系中的NaCl浓度对材料表面纤维蛋白原吸附性的影响,结果表明,随着聚合物特性粘数的增大,材料表面的纤维蛋白原吸附量呈降低的趋势;溶液体系中盐浓度的降低导致纤维蛋白原凝固性增强,在纯纤维蛋白原溶液中,材料表面纤维蛋白原的吸附量相应增多,而在稀释血浆中,纤维蛋白原的吸附量相应减少,在达到最低值后又有上升的趋向,表明纤维蛋白原在材料表面的吸附还受血浆中其它大分子的影响。 相似文献
98.
Effect of biologically active coating on biocompatibility of Nitinol devices designed for the closure of intra-atrial communications 总被引:5,自引:0,他引:5
Kong X Grabitz RG van Oeveren W Klee D van Kooten TG Freudenthal F Qing M von Bernuth G Seghaye MC 《Biomaterials》2002,23(8):1775-1783
Anti-thrombogenicity and rapid endothelialisation are prerequisites for the use of closure devices of intra-atrial communications in order to reduce the risk of cerebral embolism. The purpose of this study was therefore to assess the effect of bioactive coatings on biocompatibility of Nitinol coils designed for the closure of intra-atrial communications. Nitinol coils (n = 10, each) and flat Nitinol bands (n = 3, each) were treated by basic coating with poly(amino-p-xylylene-co-p-xylylene) and then coated with either heparin, r-hirudin or fibronectin. Anti-thrombogenicity was studied in vitro in a dynamic model with whole blood by partial thromboplastin time (PTT), platelet binding and thrombin generation, respectively, and cytotoxicity by hemolysis. Endothelialisation was studied on Nitinol bands with human umbilical venous endothelial cells (HUVEC) by 3-(4,5-dimethylthiazole-2yl)-2,5-triphenyl tetrazolium (MTT) assay and immnuofluorescence analysis of Ki67, vinculin, fibronectin and von Willebrand Factor. Uncoated or coated devices did not influence hemolysis and PTT. r-Hirudin (but not heparin) and fibronectin coating showed lower platelet binding than uncoated Nitinol (p < 0.005, respectively). Heparin and r-hirudin coating reduced thrombin formation (p < 0.05 versus Nitinol, respectively). HUVEC adhesion, proliferation, and matrix formation decreased in the order: fibronectin coating > uncoated Nitinol > r-hirudin coating > heparin coating > basic coating. MTT assay corroborated these findings. In conclusion, r-hirudin and fibronectin coating, by causing no acute cytotoxicity, decreasing thrombogenicity and increasing endothelialisation improve in vitro biocompatibility of Nitinol devices designed for the closure of intra-atrial communications. 相似文献
99.
Stereoselective determination of cetirizine and studies on pharmacokinetics in rat plasma 总被引:2,自引:0,他引:2
Choi SO Lee SH Kong HS Kim EJ Choo HY 《Journal of chromatography. B, Biomedical sciences and applications》2000,744(1):201-206
Enantiomers may confer benefits over racemates in therapeutic uses and we developed a chiral separation method of cetirizine enantiomers, a second generation H1 histamine receptor antagonist, in rat plasma. alpha1-Acidglycoprotein based chiral stationary phase(AGP-CSP), monitored with UV at 230 nm was used to separate the enantiomers. Observed enantioselectivity (alpha) was 2.0. The AGP-CSP was also used at a preparative scale to isolate the enantiomers with an optical purity of greater than ee 99%. In addition, an analysis was carried out for the cetirizine enantiomers in rat plasma to study the differences of enantiomers in pharmacokinetics. Both (+)- and (-)-cetirizine were separated using a reversed-phase column of AGP, and were detected at the range of 2.5-200 microg ml(-1) in plasma. Although there was no recognizable differences in pharmacokinetics between the enantiomers in rat, the method appears to be useful for their pharmacokinetic studies. 相似文献
100.
运用敏感的B_9细胞增殖试验检测了81例多发性骨髓瘤(MM)患者血清IL-6活性,同时分析了标本的几种急性相蛋白含量,结果表明,68%MM患者血清中IL-6活性大于5μ/ml(正常对照为5μ/ml以下),几种急性相蛋白中C-反应性蛋白(CRP)在MM时升高(P<0.01),平均达正常对照组的17倍以上,MM患者补体C_4与正常对照组无差异(p>0.05),C_3、白蛋白及转铁蛋白在MM时分别比正常下降24.42%、38.83%和32.80%,且与疾病分期有关,在血清IL-6大于5μ/ml的55例中,IL-6活性与CRP、C_3、白蛋白的相关系数分别为0.46,-0.34和-0.29,IL-6与转铁蛋白浓度相关不明显。本文结果提示:CRP、C_3及白蛋白等含量的变化可作为反映MM病情的简易而敏感的指标。 相似文献