全文获取类型
收费全文 | 29623篇 |
免费 | 2817篇 |
国内免费 | 2177篇 |
专业分类
耳鼻咽喉 | 218篇 |
儿科学 | 406篇 |
妇产科学 | 343篇 |
基础医学 | 3411篇 |
口腔科学 | 531篇 |
临床医学 | 3956篇 |
内科学 | 4513篇 |
皮肤病学 | 264篇 |
神经病学 | 1472篇 |
特种医学 | 1288篇 |
外国民族医学 | 12篇 |
外科学 | 3356篇 |
综合类 | 4869篇 |
现状与发展 | 7篇 |
一般理论 | 3篇 |
预防医学 | 1908篇 |
眼科学 | 683篇 |
药学 | 3151篇 |
27篇 | |
中国医学 | 1589篇 |
肿瘤学 | 2610篇 |
出版年
2024年 | 92篇 |
2023年 | 437篇 |
2022年 | 1099篇 |
2021年 | 1374篇 |
2020年 | 1039篇 |
2019年 | 939篇 |
2018年 | 971篇 |
2017年 | 918篇 |
2016年 | 941篇 |
2015年 | 1322篇 |
2014年 | 1617篇 |
2013年 | 1465篇 |
2012年 | 1946篇 |
2011年 | 2342篇 |
2010年 | 1493篇 |
2009年 | 1163篇 |
2008年 | 1518篇 |
2007年 | 1577篇 |
2006年 | 1521篇 |
2005年 | 1493篇 |
2004年 | 1146篇 |
2003年 | 1147篇 |
2002年 | 1028篇 |
2001年 | 871篇 |
2000年 | 803篇 |
1999年 | 749篇 |
1998年 | 439篇 |
1997年 | 503篇 |
1996年 | 340篇 |
1995年 | 299篇 |
1994年 | 235篇 |
1993年 | 189篇 |
1992年 | 229篇 |
1991年 | 213篇 |
1990年 | 184篇 |
1989年 | 164篇 |
1988年 | 133篇 |
1987年 | 139篇 |
1986年 | 120篇 |
1985年 | 77篇 |
1984年 | 50篇 |
1983年 | 28篇 |
1982年 | 16篇 |
1981年 | 18篇 |
1980年 | 25篇 |
1979年 | 45篇 |
1978年 | 22篇 |
1976年 | 12篇 |
1975年 | 18篇 |
1974年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
LJM, a 41-year-old schizophrenic Chinese man with bilateral anterior cingulate gyrus (Brodmann's area 24) lesions and also a small lesion in right amygdala after an operation, was compared with normal as well as brain-damaged and schizophrenic controls in identification of morphed facial expressions of six basic emotions. In repeated administrations of the test for recognition of facial emotions, over a 1- year period, LJM performed significantly worse for expressions of fear compared with the three groups of controls. Recognition of other emotions was not significantly different from that of the controls, except that his recognition of disgust during the first session (but not in two subsequent sessions) was worse than normal and brain-damaged controls but not worse than schizophrenic controls. The dissociation between recognition of fear and other emotions supported the view that the brain has separable networks for processing different emotions, and that the right amygdala as well as the anterior part of bilateral cingulate gyrus are possible substrates involved in the special network for perception of fear. The results from the various groups of Chinese subjects indicate that they perceive emotions in a categorical manner, and that the six basic emotions are likely to be cross-cultural universals. 相似文献
42.
Marcie R Finney Nicholas J Greco Stephen E Haynesworth Joseph M Martin David P Hedrick Jimmy Z Swan Daniel G Winter Suzanne Kadereit Matthew E Joseph Pingfu Fu Vincent J Pompili Mary J Laughlin 《Biology of blood and marrow transplantation》2006,12(5):585-593
Endothelial precursor cells (EPCs) cultured from adult bone marrow (BM) have been shown to mediate neovasculogenesis in murine models of vascular injury. We sought to directly compare umbilical cord blood (UCB)- and BM-derived EPC surface phenotypes and in vivo functional capacity. UCB and BM EPCs derived from mononuclear cells (MNC) were phenotyped by surface staining for expression of stromal (Stro-1, CXCR4, CD105, and CD73), endothelial (CD31, CD146, and vascular endothelial [VE]-cadherin), stem cell (CD34 and CD133), and monocyte (CD14) surface markers and analyzed by flow cytometry. The nonobese diabetic/severe combined immunodeficiency murine model of hind-limb ischemia was used to analyze the potential of MNCs and culture-derived EPCs from UCB and BM to mediate neovasculogenesis. Histologic evaluation of the in vivo studies included capillary density as a measure of neovascularization. Surface CXCR4 expression was notably higher on UCB-derived EPCs (64.29%+/-7.41%) compared with BM (19.69%+/-5.49%; P=.021). Although the 2 sources of EPCs were comparable in expression of endothelial and monocyte markers, BM-derived EPCs contained higher proportions of cells expressing stromal cell markers (CD105 and CD73). Injection of UCB- or BM-derived EPCs resulted in significantly improved perfusion as measured by laser Doppler imaging at days 7 and 14 after femoral artery ligation in nonobese diabetic/severe combined immunodeficiency mice compared with controls (P<.05). Injection of uncultured MNCs from BM or UCB showed no significant difference from control mice (P=.119; P=.177). Tissue samples harvested from the lower calf muscle at day 28 demonstrated increased capillary densities in mice receiving BM- or UCB-derived EPCs. In conclusion, we found that UCB and BM-derived EPCs differ in CXCR4 expression and stromal surface markers but mediate equivalent neovasculogenesis in vivo as measured by Doppler flow and histologic analyses. 相似文献
43.
为探讨细胞外间质主要成分透明质酸(HA)与层粘连蛋白(LN)在缺血性股骨头坏死(INFH)中的生理病理过程及临床价值,采用放射免疫分析法对45例不同病因的INFH患者进行了血清HA与LN的定量分析,并与30例正常人对照。结果显示,INFH患者血清HA含量极显著地高于对照组(t=3-29;P<0-01)。尤以激素性INFN增高最为显著(t=3-62;P<0-01)。INFH患者LN含量亦明显高于对照组(t=2-84;P<0-01)。同时,HA与LN含量增高与病程发展密切相关。故定量检测HA与LN可作为INFH早期诊断及判断预后的良好指标 相似文献
44.
The aim of this study was to examine the frequency of occurrence of autoantibodies against beta1-adrenoceptors in patients with hepatitis virus myocarditis (HVM) and its possible correlation with clinical characteristics. A total of 103 patients with viral myocarditis were divided into a positive group (HVM group, n=29) and a negative group (Non-HVM group, n=74) according to the laboratory findings regarding their type of hepatitis virus. The study parameters included UCG, ECG, biochemical findings and screening of autoantibodies against beta1-adrenoceptor. It was shown that the positive rate of the hepatitis virus was 28.16% (29/103) in patients with viral myocarditis. The severity of myocardial or liver injuries and the frequency of occurrence of autoantibodies against beta1-adrenoceptors in patients with viral myocarditis were more pronounced, before treatment, in the HVM group than in the Non-HVM group. The positive rates of the antibodies against the hepatitis virus and the autoantibodies against beta1-adrenoceptors were highly consistent in patients with HVM (p<0.05). In conclusion, the frequency of occurrence of the autoantibodies against beta1-adrenoceptors may be one important marker of HVM and, thus, possibly involved in the pathogenesis of the HVM. 相似文献
45.
Intending to clarify the true Incidence of Invasive lobular carcinoma of the breast In Japanese women as well as the frequency of unilateral multlcentriclty, 362 cases of clinically defined monocentrlc breast cancer without pre-operative biopsy (previously fine needle aspiration or needle biopsy were routinely carried out for every case) were examined by whole mammary gland serial sectioning. On the basis of pathology and the World Health Organization classification of breast tumors, each case was assigned to one of two main histologlc types: Invasive lobular carcinoma (ILC) or Invasive ductal carcinoma (IDC). Invasive lobular carcinoma was further separated into classic and variant types by employing previously published criteria. Twenty-one cases of ILC (5.8%) were diagnosed, which Is more than In most previous Japanese studies. Unilateral multicentric breast carcinoma was detected In 9.5% of ILC and 16.1% of IDC (the difference was found not significant). Microscopically, ILC tumors were found to be, on average, larger than IDC. Patients with classic type ILC tended to be younger than those with variant type or IDC. Estrogen receptor expression was found more frequently In variant type ILC than in classic type. These results suggest that the incidence of invasive lobular carcinoma of the breast In Japanese women is low and that unilateral multicentricity Is not significantly higher in ILC than in IDC. 相似文献
46.
马富 《中国临床解剖学杂志》1989,7(3):151-153
为给神经末梢冷冻治疗跟痛提供穿刺定位依据,在52侧下肢中对跟内侧支和跟外侧支的体表投影进行了观测。跟内侧支约有69.8%通过内踝跟结节线的中份,另有28.3%跟内侧支起于该线中份下方距离7.3mm处;跟外侧支约有70.2%通过外踝跟结节线的中份,另有22.8%跟外侧支起于该线下方距离5.8mm 处。据此冷冻治疗跟痛的进针部位可以选在内、外踝与跟结节连线的中份下方垂直距离5mm 处。 相似文献
47.
API0134对大鼠血浆和血小板血栓素B2生成与血小板聚集的影响 总被引:2,自引:0,他引:2
用放射免疫分析法和比浊法测定PAI0134对大鼠血浆血栓素B2浓度,血小板TXB2生成血小板聚集的影响。静脉注射API013470mg或100mg.kg显著降低血浆TXB2浓度,其降低2率分别为38.8%和51.6%,API0134明显抑制ADP诱导的大鼠血小板聚集和TXB2生成,抑制率分别为27.8%,39.5%,和41.4%,53.6%,两抑制率间呈显著正相关。 相似文献
48.
49.
酵母双杂合系统AD端阴离子交换蛋白C-末端表达质粒的构建 总被引:2,自引:0,他引:2
利用PCR方法,从阴离子交换蛋白1(AE1)全长cDNA中扩增出约350bp c末端cDNA片段,测序后将其克隆至pGADT7载体上,用醋酸锂法构建好的pADT7-AE1-c末端转染酵母菌HA109,观察其在选择性培养基上的表达情况。结果表明,获得了530bp AE1c-末端cDNA,pGADT7-AE1-c末端对酵母无毒性,不能激活检测基因,可作为酵母双杂合系统中的靶基因。 相似文献
50.
Many residues involved in polymorphic antibody-binding epitopes on class II molecules are located on the -helix of DRβ chains. Although they have received less attention, residues in the peptide-binding groove and second domain of the DRβ chain may also be critical for polymorphic anti-DR antibody epitopes. In this study, we used transfectants expressing site-directed mutations at positions in the HLA-DR β1 and β2 domains and flow cytometry to define the epitopes of several polymorphic anti-DR antibodies. Both DR(β 1*0403) residues 14 and 25 were shown to be involved in the epitopes of mAbs DA6. 164, HU-20, Q5/6, and 50D6, and DR(β 1*0701) residue 14 was shown to be critical for the epitopes of two DR7-specific mAbs, SFR16-DR7M and TAL 13. 1. Unlike most other residues shown to be important in antibody-binding epitopes, residue 14 is located in the floor of the peptide-binding groove and residue 25 is in an outer loop, each with their side chains pointing down, such that antibodies may directly contact these residues from below the binding groove. Two residues in the β2 domain, β180 and β181, were also shown to be involved in the epitopes of three polymorphic anti-DR mAbs, NFLD.D1, NFLD.M1, and LY9. Although these two residues are close to the transmembrane domain in the linear sequence, their solvent accessibility in the DR1 structures is quite impressive. Our data provide new evidence that residues accessible under the peptidebinding groove contribute to polymorphic antibody-binding epitopes. 相似文献