全文获取类型
收费全文 | 19798篇 |
免费 | 1624篇 |
国内免费 | 576篇 |
专业分类
耳鼻咽喉 | 172篇 |
儿科学 | 307篇 |
妇产科学 | 563篇 |
基础医学 | 2548篇 |
口腔科学 | 409篇 |
临床医学 | 2208篇 |
内科学 | 4096篇 |
皮肤病学 | 238篇 |
神经病学 | 1223篇 |
特种医学 | 502篇 |
外国民族医学 | 3篇 |
外科学 | 2668篇 |
综合类 | 1564篇 |
现状与发展 | 4篇 |
一般理论 | 5篇 |
预防医学 | 1110篇 |
眼科学 | 762篇 |
药学 | 1621篇 |
6篇 | |
中国医学 | 590篇 |
肿瘤学 | 1399篇 |
出版年
2024年 | 38篇 |
2023年 | 228篇 |
2022年 | 479篇 |
2021年 | 717篇 |
2020年 | 467篇 |
2019年 | 499篇 |
2018年 | 578篇 |
2017年 | 514篇 |
2016年 | 501篇 |
2015年 | 676篇 |
2014年 | 830篇 |
2013年 | 936篇 |
2012年 | 1414篇 |
2011年 | 1509篇 |
2010年 | 894篇 |
2009年 | 734篇 |
2008年 | 1109篇 |
2007年 | 1116篇 |
2006年 | 1149篇 |
2005年 | 1140篇 |
2004年 | 930篇 |
2003年 | 794篇 |
2002年 | 794篇 |
2001年 | 550篇 |
2000年 | 540篇 |
1999年 | 495篇 |
1998年 | 190篇 |
1997年 | 201篇 |
1996年 | 163篇 |
1995年 | 122篇 |
1994年 | 115篇 |
1993年 | 79篇 |
1992年 | 207篇 |
1991年 | 189篇 |
1990年 | 169篇 |
1989年 | 150篇 |
1988年 | 119篇 |
1987年 | 115篇 |
1986年 | 96篇 |
1985年 | 64篇 |
1984年 | 43篇 |
1983年 | 31篇 |
1982年 | 45篇 |
1981年 | 39篇 |
1980年 | 35篇 |
1979年 | 36篇 |
1978年 | 32篇 |
1977年 | 19篇 |
1975年 | 20篇 |
1973年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
Five haplotypes account for fifty-five percent of ATM mutations in Brazilian patients with ataxia telangiectasia: seven new mutations 总被引:7,自引:0,他引:7
Coutinho G Mitui M Campbell C Costa Carvalho BT Nahas S Sun X Huo Y Lai CH Thorstenson Y Tanouye R Raskin S Kim CA Llerena J Gatti RA 《American journal of medical genetics. Part A》2004,(1):33-40
We have studied the molecular genetics of 27 Brazilian families with ataxia telangiectasia (AT). Five founder effect haplotypes accounted for 55.5% of the families. AT is an autosomal recessive disorder of childhood onset characterized by progressive cerebellar ataxia, ocular apraxia, telangiectasia, immunodeficiency, radiation sensitivity, chromosomal instability, and predisposition to cancer. The ATM gene spans more than 150 kb on chromosome region 11q23.1 and encodes a product of 3056 amino acids. The ATM protein is a member of the phosphatidylinositol 3-kinase (PI-3K) family of proteins and is involved in cell cycle control and DNA repair pathways. DNA was isolated from lymphoblastoid cell lines and haplotyped using four STR markers (D11S1818, NS22, D11S2179, D11S1819) within and flanking the ATM gene; all allele sizes were standardized in advance. In addition to the STR haplotypes, SNP haplotypes were determined using 10 critical polymorphisms. The entire gene was screened sequentially by protein truncation testing (PTT), single strand conformation polymorphism (SSCP), and then denaturing high performance liquid chromatography (dHPLC) to identify the disease-causing mutations. Of the expected 54 mutations, 50 were identified. All mutations but one, led to a truncated or null form of the ATM protein (nonsense, splice site, or frameshift). Five families (18.5%) carried a deletion of 3450nt (from IVS28 to Ex31), making this one of the two most common Brazilian mutations. Mutations were located throughout the entire gene, with no clustering or hotspots. Standardized STR haplotype analysis greatly enhanced the efficiency of mutation screening. 相似文献
162.
163.
Lai PS Takeshima Y Adachi K Van Tran K Nguyen HT Low PS Matsuo M 《Journal of human genetics》2002,47(10):0552-0555
The frequency and distribution of deletions of 19 deletion-prone exons clustered in two hot spots in the proximal and central
regions of the dystrophin gene were compared in three populations from Singaporean, Japan, and Vietnam. DNA samples obtained
from 105 Singaporean, 86 Japanese, and 34 Vietnamese Duchenne muscular dystrophy patients were examined by polymerase chain
reaction amplification. Deletions of the examined exons were found in 51.2% of Japanese patients but in 40.0% or less of the
Singaporeans and Vietnamese. About two thirds of the deletions were localized in the central region and the remaining deletions
were clustered at the proximal region. The most commonly deleted exons at the central deletion hot spot were exon 50 in the
Singaporean, exons 49 and 50 in the Japanese, and exon 51 in the Vietnamese population. At the proximal deletion hot spot,
the most commonly deleted exons were exons 6 and 8 in the Singaporeans, exons 12 and 17 in the Japanese, and exons 8 and 12
in the Vietnamese. Two cases each from Singapore and Japan had large-scale gross mutations spanning both deletion hot spots.
Our results suggest that, although the presence and frequency of the two deletion hot spots may be similar in the three Asian
populations analyzed, the distribution and frequency of deletions among the different exons can vary as a result of population-specific
intronic sequences that predispose individuals to preferential deletion breakpoints.
Received: May 20, 2002 / Accepted: July 1, 2002 相似文献
164.
165.
本实验通过结扎兔冠状动脉左室支复制动脉缺血-再灌注模型,应用心外膜接触电极记录单相动作电位,观察后除极电位在再灌注性心律失常中及镁离子的拮抗作用。结果表明,再灌性心律失常的52.6%与早期后去极化有关。硫酸镁可终止及预防RA,对再灌中出现触发活动有抑制作用。 相似文献
166.
本文采用放免法测定实验性犬心肌梗塞和溶栓后再闭塞时血浆中GMP-140、TXB2、6-K-PGF1α的含量变化,并探讨其与心肌梗塞溶栓后再闭塞的关系。结果表明,在血栓形成时血浆中TXA2稳定代谢产物TXB2水平显著升高(p〈0.05),在溶栓后再闭塞率高(87.5%)的非治疗组(B组)。在溶栓后4小时至溶栓后3天期间呈进行性升高(p〈0.01),而在再 埘经低(16.7%)的API0134治疗组( 相似文献
167.
Wen-Po Lin Hsing-Lung Lai Yi-Lin Liu Yin-Mei Chiung Chia-Yang Shiau Jun-Ming Han Chuen-Mi Yang Yu-Tien Liu 《Journal of microbiology, immunology, and infection》2005,38(5):320-326
A recombinant plasmid, pYL-1, containing a tyrosinase gene whose expression is under the control of a phage T5 promoter and 2 lac operators, was constructed. Escherichia coli JM109 harboring pYL-1 was used for production of bacterial melanin. A simple procedure for the isolation and purification of melanin was developed. The ultraviolet (UV)-visible light absorption spectra of melanin prepared by chemical synthesis and derived from different organisms, including bacteria, a plant and an animal source, were determined. Melanins produced by both bacteria and chemical synthesis showed a steady increase of absorption at wavelengths of UV light ranging from approximately 200-400 nm, while melanin derived either from plant or animal sources showed an additional discrete absorption peak at wavelength 280 nm upon a similar steady increase of absorption. This additional absorption peak could be due to the presence of protein-bound melanins in animal and plant sources while a free form of melanin was obtained from bacteria and chemical synthesis. Analysis of the effect of bacterial melanin on the activity of antibiotics against E. coli revealed that the activities of polymyxin B, kanamycin, tetracycline, and ampicillin were markedly reduced in the presence of melanin, whereas the activity of norfloxacin was not affected. The reduction of the antibacterial activity may result directly from the interaction of antibiotics with melanin. However, the mechanism of this interaction remains to be demonstrated. 相似文献
168.
Prominent proliferative response of peripheral blood mononuclear cells to a recombinant non-structural (NS3) protein of hepatitis C virus in patients with chronic hepatitis C.
下载免费PDF全文
![点击此处可从《Clinical and experimental immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
P M Yang L H Hwang M Y Lai W L Huang Y D Chu W K Chi B L Chiang J H Kao P J Chen D S Chen 《Clinical and experimental immunology》1995,101(2):272-277
The proliferative response of peripheral blood mononuclear cells (PBMC) to a recombinant non-structural (NS3) protein of hepatitis C virus (HCV) was studied in 41 patients with chronic hepatitis C. Of them, 28 had chronic persistent hepatitis (CPH) and 13 chronic active hepatitis (CAH). The positive proliferation rate of PBMC to the recombinant NS3 protein, T9Ag, was 66% in the 41 patients (77% in CAH versus 61% in CPH; P > 0.05) when stimulation index (SI) = 4 was set as the cut-off value. However, mean SI of CAH patients was significantly higher than that of CPH patients (8.3 +/- 5.2 versus 5.1 +/- 3.6; P < 0.05). Six other chronic hepatitis patients who were repeatedly negative for anti-HCV antibody but positive for serum HCV RNA also had an SI of > or = 4.0. The frequency of cellular immune response to the T9Ag is among the highest results obtained by using HCV antigens tested so far. Our studies thus indicate that NS3 is an immunologically important region of HCV for T cells. Moreover, the proliferative response to T9Ag may help to establish hepatitis C etiology in chronic hepatitis patients who are seronegative with currently available anti-HCV assays. 相似文献
169.
170.
Yi-Giien Tsai Jenn-Haung Lai San-Yuan Kuo Hsiang-Cheng Chen Deh-Ming Chang 《Journal of microbiology, immunology, and infection》2005,38(3):218-220
Good's syndrome is extremely rare and refers to an acquired B and T cell immunodeficiency in thymoma patients. We report a 51-year-old female thymoma patient who presented with recurrent herpes zoster, pneumonia, diarrhea and opportunistic infections. She was found to have acquired hypogammaglobulinemia with absent B cells. Despite repeat intravenous immunoglobulin replacement and antibiotic therapy, she died of bacterial pneumonia-induced acute respiratory distress syndrome. Clinicians should look for evidence of immunologic dysfunction in thymoma patients presenting with recurrent infections. 相似文献