全文获取类型
收费全文 | 14287篇 |
免费 | 1456篇 |
国内免费 | 1151篇 |
专业分类
耳鼻咽喉 | 69篇 |
儿科学 | 176篇 |
妇产科学 | 130篇 |
基础医学 | 1586篇 |
口腔科学 | 332篇 |
临床医学 | 1929篇 |
内科学 | 2269篇 |
皮肤病学 | 154篇 |
神经病学 | 811篇 |
特种医学 | 503篇 |
外国民族医学 | 5篇 |
外科学 | 1622篇 |
综合类 | 2423篇 |
现状与发展 | 4篇 |
一般理论 | 1篇 |
预防医学 | 976篇 |
眼科学 | 418篇 |
药学 | 1451篇 |
1篇 | |
中国医学 | 671篇 |
肿瘤学 | 1363篇 |
出版年
2024年 | 39篇 |
2023年 | 241篇 |
2022年 | 566篇 |
2021年 | 722篇 |
2020年 | 571篇 |
2019年 | 502篇 |
2018年 | 534篇 |
2017年 | 425篇 |
2016年 | 443篇 |
2015年 | 657篇 |
2014年 | 778篇 |
2013年 | 669篇 |
2012年 | 966篇 |
2011年 | 1119篇 |
2010年 | 727篇 |
2009年 | 548篇 |
2008年 | 741篇 |
2007年 | 751篇 |
2006年 | 643篇 |
2005年 | 681篇 |
2004年 | 533篇 |
2003年 | 509篇 |
2002年 | 456篇 |
2001年 | 399篇 |
2000年 | 383篇 |
1999年 | 384篇 |
1998年 | 283篇 |
1997年 | 250篇 |
1996年 | 178篇 |
1995年 | 174篇 |
1994年 | 108篇 |
1993年 | 101篇 |
1992年 | 129篇 |
1991年 | 98篇 |
1990年 | 108篇 |
1989年 | 79篇 |
1988年 | 77篇 |
1987年 | 69篇 |
1986年 | 64篇 |
1985年 | 47篇 |
1984年 | 40篇 |
1983年 | 8篇 |
1982年 | 13篇 |
1981年 | 13篇 |
1980年 | 9篇 |
1979年 | 10篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 5篇 |
1966年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
目的 检验幼师女生自尊水平与心理健康的关系。方法 使用自尊量表和SCL-90量表对196名幼师女生进行测量。结果 幼师女生的心理健康总体水平不高,幼师女生自尊水平与心理健康之间存在的显著的负相关。结论 一方面幼师女生的自尊受心理健康水平的影响,特别是抑郁、强迫和人际敏感等方面;另一方面幼师女生的自尊也会影响她们的心理健康水平。 相似文献
92.
Bottini N Otsu A Borgiani P Saccucci P Stefanini L Greco E Fontana L Hopkins JM Mao XQ 《Clinical genetics》2003,63(3):228-231
Protein tyrosine phosphatases (PTPases) have recently been recognized as important modulators of various signal transduction pathways in immune cells. Genetic polymorphisms have been described in genes codifying for members of this family of enzymes, and the genetics of PTPases is predicted to play an important role in the etiology of immune diseases and of their clinical variability. The low molecular weight protein tyrosine phosphatase (ACP1 or LMPTP) is one of the few PTPases with a known genetic polymorphism, and has been proposed to be associated with atopic dermatitis in a small sample from an Italian population. In this paper we describe the association of the ACP1 polymorphism with total IgE levels in two independent samples from English and Italian populations. In both the samples the mean value of serum IgE is lower among subjects carrying the BC genotype than in other ACP1 genotypes. The BC genotype is associated with the highest total ACP1 enzymatic activity. Our data suggest that one or both of the ACP1 isoforms exert an inhibitory role on some signal transduction pathway relevant for IgE hyperproduction. 相似文献
93.
94.
Yin C Ying L Zhang PC Zhuo RX Kang ET Leong KW Mao HQ 《Journal of biomedical materials research. Part A》2003,67(4):1093-1104
Galactosylated surface is an attractive substrate for hepatocyte culture because of the specific interaction between the galactose ligand and the asialoglycoprotein receptor on hepatocytes. In this study, we described a scheme to achieve high density of immobilized galactose ligands on polyethylene terephthalate (PET) surface by first surface-grafting polyacrylic acid on plasma-pretreated PET film under UV irradiation, followed by conjugation of a galactose derivative (1-O-(6'-aminohexyl)-D-galactopyranoside) to the grafted polyacrylic acid chains. A high galactose density of 513 nmol/cm(2) on the PET surface was used in this study to investigate the behavior of cultured hepatocyte. This engineered substrate showed high affinity to fluorescein isothiocyanate-lectin binding. Primary rat hepatocytes, when seeded at a density of 2 x 10(5) cells/cm(2), attached to the galactosylated PET substrate at a similar efficiency compared with collagen-coated substrate. The hepatocytes spontaneously formed aggregates 1 day after cell seeding and showed better maintenance of albumin secretion and urea synthesis functions than those cultured on collagen-coated surface. 相似文献
95.
96.
Sabra MM Damcott C Fu M Ott S O'Connell JR Mitchell BD Shuldiner AR 《Molecular genetics and metabolism》2005,85(2):133-139
OBJECTIVE: The vesicle-associated membrane protein-4 (VAMP4) gene is an excellent type 2 diabetes (T2DM) positional candidate gene. It is located on chromosome 1q24-q25, a region of linkage to T2DM in the Amish and several other populations. VAMP4 is expressed in liver and skeletal muscle and participates in intracellular trafficking of secreted and membrane-associated proteins. DESIGN AND METHODS: We sequenced VAMP4 in 20 Amish subjects. Polymorphisms in and around VAMP4 were genotyped in 65 Amish subjects with T2DM, 64 subjects with impaired glucose homeostasis (IGH), and 126 normal glucose tolerant controls, as well as in an expanded set of 749 participants of the Amish Family Diabetes Study for whom glucose and insulin levels during an oral glucose tolerance test (OGTT) and other quantitative traits related to diabetes were available. Case-control and quantitative trait association analyses were performed. RESULTS: We found three common non-coding intragenic polymorphisms: a 23bp insertion/deletion (I/D) in the 5' untranslated region (UTR) in exon 1 at position 73127, and G35319T and C335296T single nucleotide polymorphisms (SNPs) in the 3' UTR (NCBI Accession No. Z98751). The two 3' UTR SNPs were in complete linkage disequilibrium (LD) and both were in strong LD with the exon 1 I/D polymorphism (|D'|=0.82). Similarly, three extragenic flanking SNPs (rs978985, rs203255, and rs1023479) showed moderate LD with the neighboring intragenic SNPs (|D'|=0.23-0.69). None of the SNPs individually nor any of the 2-, 3-, 4-, or 5-polymorphism haplotypes were associated with T2DM or IGH. The exon 1 I/D polymorphism was not associated with significant differences in mean fasting or stimulated glucose or insulin levels during an OGTT or other diabetes-related quantitative traits in the expanded set of 749 subjects. CONCLUSION: Variation in VAMP4 does not significantly influence risk of T2DM or IGH in the Amish. 相似文献
97.
Effect of dosage on immunogenicity of a Vi conjugate vaccine injected twice into 2- to 5-year-old Vietnamese children 总被引:2,自引:0,他引:2 下载免费PDF全文
Canh DG Lin FY Thiem VD Trach DD Trong ND Mao ND Hunt S Schneerson R Robbins JB Chu C Shiloach J Bryla DA Bonnet MC Schulz D Szu SC 《Infection and immunity》2004,72(11):6586-6588
In a double-blind, randomized, and placebo-controlled previous trial, the efficacy of Vi-rEPA for typhoid fever in 2- to 5-year-olds was 89.0% for 46 months. Vi-rEPA contained 25 microg of Vi and induced a greater-than-eightfold rise in immunoglobulin G (IgG) anti-Vi in all of the vaccinees tested. In this investigation, we conducted a dosage-immunogenicity study of 5, 12.5, and 25 microg of Vi-rEPA in this age group. Two doses of Vi-rEPA were injected 6 weeks apart. Blood samples were taken before and at 10 weeks (4 weeks after the second injection) and 1 year later. All postimmunization geometric mean (GM) levels were higher than the preimmune levels (P < 0.0001). At 10 weeks, the GM IgG anti-Vi level elicited by 25 microg (102 EU/ml) was higher than those elicited by 12.5 microg (74.7 EU/ml) and 5 microg (43 EU/ml) (P < 0.004): all of the children had > or = 3.52 EU/ml (estimated minimum protective level). One year later, the levels declined about sevenfold (13.3 and 11.3 versus 6.43 EU/ml, P < 0.0001) but remained significantly higher than the preimmune levels (P < 0.0001), and >96% of the children had a greater-than-eightfold rise. This study also confirmed the safety and consistent immunogenicity of the four lots of Vi-rEPA used in this and previous trials. 相似文献
98.
831名健康青年庚型肝炎病毒和人免疫缺陷病毒感染?… 总被引:1,自引:0,他引:1
目的 了解我国健康青年中庚型肝炎病毒(HGV)和人免疫缺陷病毒的感染情况。方法 采用酶联免疫法(EIA)检测6省831名健康青年血清中的HGV和HIV抗体,对抗-HGVIgG阳性的血清再用逆转录-巢式聚合酶链反应(RT-PCR)检测HGVRNA。结果 发现抗-HGV IgG阳性率为2.53%(21/831),21例阳性者中HGV RNA阳性8例,两者符合率为38.1%;抗-HIV均阴性。结论 我 相似文献
99.
Hepatocytes are anchorage-dependent cells sensitive to microenvironment; the control of the physicochemical properties of the extra-cellular matrices may be useful to the maintenance of hepatocyte functions in vitro for various applications. In a microcapsule-based 3-D hepatocyte culture microenvironment, we could control the physical properties of the collagen nano-fibres by fine-tuning the complex-coacervation reaction between methylated collagen and terpolymer of hydroxylethyl methacrylate-methyl methacrylate-methylacrylic acid. The physical properties of the nano-fibres were quantitatively characterized using back-scattering confocal microscopy to help optimize the physical support for hepatocyte functions. We further enhanced the chemical properties of the collagen nano-fibres by incorporating galactose onto collagen, which can specifically interact with the asialoglycoprotein receptor on hepatocytes. By correlating a range of collagen nano-fibres of different physicochemical properties with hepatocyte functions, we have identified a specific combination of methylated and galactosylated collagen nano-fibres optimal for maintaining hepatocyte functions in vitro. A model of how the physical and chemical supports interplay to maintain hepatocyte functions is discussed. 相似文献
100.
The specific recognition between asialoglycoprotein receptor and galactose ligand at cell-substrate interfaces has been shown to mediate hepatocyte adhesion and maintain liver specific functions of hepatocytes. Conventionally, the success of hepatocyte attachment on engineered tissue scaffold is inferred from the degree of two-dimensional cell spreading that is measured by transmitted light microscopy. However, the actual contact mechanics and adhesion strength of hepatocytes during two-dimensional cell spreading has not been elucidated due to lack of biophysical probe. In this study, a novel biophysical technique known as confocal reflectance interference contrast microscopy (C-RICM) in conjunction with phase contrast microscopy is utilized to probe the adhesion dynamics, contact mechanics and two-dimensional spreading kinetics of HepG2 cells on galactose immobilized and collagen gel coated substrates. C-RICM demonstrates that HepG2 cells form strong adhesion contacts with both galactose-immobilized surfaces and collagen gel coated substrates. Moreover, HepG2 cells maintain their compact shapes in the presence of asialoglycoprotein receptor-mediated recognition while they become exceedingly spread under integrin-mediated adhesion on collagen gel coated substrate. The initial rate of adhesion contact formation and the steady-state adhesion energy of HepG2 cell population are highest on substrate conjugated with galactose ligand via a longer spacer. The adhesion dynamics and final adhesion energy of HepG2 cells depends both on the type of ligand-receptor interaction and the length of spacer between the ligand and substrate. Most importantly, new biophysical insights into the initial hepatocyte attachment that are critical for hepatocyte culture are provided through the decomposition of two-dimensional spreading and adhesion contact formation on bio-functional substrates. 相似文献