全文获取类型
收费全文 | 21221篇 |
免费 | 1744篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 313篇 |
儿科学 | 594篇 |
妇产科学 | 461篇 |
基础医学 | 2987篇 |
口腔科学 | 444篇 |
临床医学 | 1971篇 |
内科学 | 4981篇 |
皮肤病学 | 239篇 |
神经病学 | 2001篇 |
特种医学 | 645篇 |
外科学 | 3389篇 |
综合类 | 299篇 |
一般理论 | 16篇 |
预防医学 | 1611篇 |
眼科学 | 580篇 |
药学 | 1154篇 |
中国医学 | 38篇 |
肿瘤学 | 1317篇 |
出版年
2023年 | 157篇 |
2022年 | 299篇 |
2021年 | 777篇 |
2020年 | 405篇 |
2019年 | 612篇 |
2018年 | 739篇 |
2017年 | 483篇 |
2016年 | 495篇 |
2015年 | 607篇 |
2014年 | 787篇 |
2013年 | 1038篇 |
2012年 | 1503篇 |
2011年 | 1525篇 |
2010年 | 830篇 |
2009年 | 708篇 |
2008年 | 1251篇 |
2007年 | 1235篇 |
2006年 | 1222篇 |
2005年 | 1154篇 |
2004年 | 1064篇 |
2003年 | 933篇 |
2002年 | 922篇 |
2001年 | 151篇 |
2000年 | 137篇 |
1999年 | 165篇 |
1998年 | 180篇 |
1997年 | 165篇 |
1996年 | 137篇 |
1995年 | 126篇 |
1994年 | 117篇 |
1993年 | 113篇 |
1992年 | 107篇 |
1991年 | 102篇 |
1990年 | 110篇 |
1989年 | 90篇 |
1988年 | 106篇 |
1987年 | 113篇 |
1986年 | 76篇 |
1985年 | 105篇 |
1984年 | 106篇 |
1983年 | 101篇 |
1982年 | 135篇 |
1981年 | 125篇 |
1980年 | 164篇 |
1979年 | 77篇 |
1978年 | 87篇 |
1977年 | 79篇 |
1976年 | 84篇 |
1975年 | 63篇 |
1974年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
111.
Effect of total lymphoid irradiation on IgE antibody responses in rheumatoid arthritis and systemic lupus erythematosus 总被引:2,自引:0,他引:2
Abba I. Terr M.D. Richard B. Moss M.D. Samuel Strober M.D. 《The Journal of allergy and clinical immunology》1987,80(6):798-802
Thirteen patients with rheumatoid arthritis and four patients with systemic lupus erythematosus and nephritis were treated with total lymphoid irradiation because of severe disease refractory to other forms of treatment. Serum samples before and after irradiation were tested for changes in total serum IgE and for changes in specific IgE antibodies to ryegrass pollen, dust mite, cat dander, and Alternaria. There were no statistically significant changes in total or specific IgE from lymphoid irradiation in these patients. The therapy caused a significant decrease in circulating total lymphocyte and Leu-3 (helper/inducer) T-lymphocyte counts. Therefore, reduction in circulating levels of helper/inducer T cells does not appear to influence preexisting levels of IgE antibodies. 相似文献
112.
113.
114.
James W. Allen Charles F. Shuler Samuel A. Latt 《Somatic Cell and Molecular Genetics》1978,4(4):393-405
5-Bromodeoxyuridine (BrdU) tablets with different physical characteristics are useful in a wide variety of studies requiring detection of DNA replication in vivo. These tablets can effect a high substitution of BrdU in DNA, thereby permitting sister chromatid differentiation in chromosomes stained with 33258 Hoechst alone or in conjunction with Giemsa. Baseline and cyclophosphamide-induced in vivo sister chromatid exchange frequencies in mouse spleen, marrow, and thymus were measured and found to be significantly greater than those in spermatogonia. Sister chromatid exchange analysis was also extended to mouse liver and to Chinese hamster and Armenian hamster marrow cells. Sister chromatid differentiation was observed in Armenian hamster meiotic tissue, and evidence for interhomolog chromatid exchange obtained. 相似文献
115.
Korthuis PT Asch SM Anaya HD Morgenstern H Goetz MB Yano EM Rubenstein LV Lee ML Bozzette SA 《Journal of acquired immune deficiency syndromes (1999)》2004,35(3):253-260
BACKGROUND: Lipid screening is recommended for patients taking protease inhibitors (PIs). METHODS: We examined data from the Veterans Administration Immunology Case Registry to assess lipid screening among HIV-infected veterans who received PIs for at least 6 consecutive months during 1999 and 2001. We estimated crude and adjusted associations between lipid screening and patient characteristics (age, gender, HIV exposure, and race/ethnicity), comorbidities (AIDS, cardiovascular disease, diabetes, hypertension, smoking, and hyperlipidemia), and facility characteristics (urban location, case management, guidelines, and quality improvement programs). RESULTS: Among 4065 patients on PIs, clinicians screened 2395 (59%) for lipids within 6 months of initiating treatment. Adjusting for patient characteristics, comorbidities, facility traits, and clustering, lipid screening was more common among patients who were cared for in urban areas (relative risk [RR] = 1.3, confidence limits: 1.0-1.5), diabetic (RR = 1.2, confidence limits: 1.1-1.3), or previously hyperlipidemic (RR = 1.4, confidence limits: 1.3-1.5) and less common among patients with a history of intravenous drug use (IVDU) (RR = 0.90, confidence limits: 0.79-1.0) or unknown HIV risk (RR = 0.85, confidence limits: 0.75-0.95). CONCLUSIONS: Six in 10 patients taking PIs receive lipid screening within 6 months of PI use. Systemic interventions to improve overall HIV quality of care should also address lipid screening, particularly among patients with unknown or IVDU HIV risk and those cared for in nonurban areas. 相似文献
116.
Schramm C Huber S Protschka M Czochra P Burg J Schmitt E Lohse AW Galle PR Blessing M 《International immunology》2004,16(9):1241-1249
117.
Tamiya G Shinya M Imanishi T Ikuta T Makino S Okamoto K Furugaki K Matsumoto T Mano S Ando S Nozaki Y Yukawa W Nakashige R Yamaguchi D Ishibashi H Yonekura M Nakami Y Takayama S Endo T Saruwatari T Yagura M Yoshikawa Y Fujimoto K Oka A Chiku S Linsen SE Giphart MJ Kulski JK Fukazawa T Hashimoto H Kimura M Hoshina Y Suzuki Y Hotta T Mochida J Minezaki T Komai K Shiozawa S Taniguchi A Yamanaka H Kamatani N Gojobori T Bahram S Inoko H 《Human molecular genetics》2005,14(16):2305-2321
A major goal of current human genome-wide studies is to identify the genetic basis of complex disorders. However, the availability of an unbiased, reliable, cost efficient and comprehensive methodology to analyze the entire genome for complex disease association is still largely lacking or problematic. Therefore, we have developed a practical and efficient strategy for whole genome association studies of complex diseases by charting the human genome at 100 kb intervals using a collection of 27,039 microsatellites and the DNA pooling method in three successive genomic screens of independent case-control populations. The final step in our methodology consists of fine mapping of the candidate susceptible DNA regions by single nucleotide polymorphisms (SNPs) analysis. This approach was validated upon application to rheumatoid arthritis, a destructive joint disease affecting up to 1% of the population. A total of 47 candidate regions were identified. The top seven loci, withstanding the most stringent statistical tests, were dissected down to individual genes and/or SNPs on four chromosomes, including the previously known 6p21.3-encoded Major Histocompatibility Complex gene, HLA-DRB1. Hence, microsatellite-based genome-wide association analysis complemented by end stage SNP typing provides a new tool for genetic dissection of multifactorial pathologies including common diseases. 相似文献
118.
119.
The effect of ethanol-induced CYP2E1 on proteasome activity: the role of 4-hydroxynonenal 总被引:6,自引:0,他引:6
Previous studies have shown that the induction of P450 cytochrome 2E1 (CYP2E1) is associated with the loss of proteasomal activities. To correlate the loss of proteasomal activity with CYP2E1 induction, ethanol was fed intragastrically for 1, 3, 7, and 15 days. The maximum induction of CYP2E1 (3.5-fold) occurred after 15 days of ethanol feeding. However, there was no significant decrease in the 26 S chymotrypsin-like and trypsin-like activity over this period of time. When ethanol was given to rats for 1 month, CYP2E1 was significantly induced, and the proteasomal activity was significantly decreased. These results indicate that proteasomal activity was not directly affected by ethanol or CYP2E1 induction. Since 4-hydroxynonenal (4-HNE) concentration was significantly increased at 1 month of ethanol feeding, it was suspected that 4-HNE adduct formation with proteasome subunits could be the mechanism of proteasome inhibition. Using an antibody to 4-HNE adducted proteins in Western blot analysis of the 26 S proteasome fraction isolated from the liver of alcohol fed rats, one extra band appeared around 44 kDa. When the antibody to an ATPase Rpt4 was used to stain the stripped membrane, the same band that was detected with the 4-HNE antibody was detected with the Rpt4 antibody. An adduct of 4-HNE formed with the Rpt4 subunit of 26 S could impede the association of 19 S and 20 S and thus account for the observed decrease of proteasomal activity. 相似文献
120.
PCR analysis of egyptian respiratory adenovirus isolates, including identification of species, serotypes, and coinfections
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Metzgar D Osuna M Yingst S Rakha M Earhart K Elyan D Esmat H Saad MD Kajon A Wu J Gray GC Ryan MA Russell KL 《Journal of clinical microbiology》2005,43(11):5743-5752
Eighty-eight adenovirus (Ad) isolates and associated clinical data were collected from walk-in patients with influenza-like illness in Egypt during routine influenza surveillance from 1999 through 2002. Respiratory Ad distributions are geographically variable, and serotype prevalence has not been previously characterized in this region. Serotype identity is clinically relevant because it predicts vaccine efficacy and correlates strongly with both clinical presentation and epidemiological pattern. Species and serotype identities were determined using several well-validated multiplex PCR protocols culled from the literature and supplemented with a few novel primer sets designed to identify rare types. The isolates included common species B1 serotypes (Ad3 and Ad7), common species C serotypes (Ad1, Ad2, and Ad5), the less common species B2 serotype Ad11, and three isolates of the rare species B1 serotype Ad16. Two isolates that appear to be variant Ad16 were also identified. Fifteen coinfections of multiple adenoviral types, primarily AdB/AdC and Ad3/Ad7 dual infections, were detected. The majority of these were verified using redundant PCR tests targeted at multiple genes. PCR is able to resolve coinfections, in contrast to traditional serum neutralization tests. PCR is also comparatively rapid and requires very little equipment. Application of the method allowed an inclusive determination of the serotypes found in the Egyptian respiratory sample set and demonstrated that coinfections are common and may play a previously unrecognized role in adenovirus pathogenesis, evolution, and epidemiology. In particular, coinfections may influence adenoviral evolution, as interserotypic recombination has been identified as a source of emerging strains. 相似文献