全文获取类型
收费全文 | 2480372篇 |
免费 | 202750篇 |
国内免费 | 4499篇 |
专业分类
耳鼻咽喉 | 35673篇 |
儿科学 | 75593篇 |
妇产科学 | 65383篇 |
基础医学 | 350955篇 |
口腔科学 | 71855篇 |
临床医学 | 222199篇 |
内科学 | 491317篇 |
皮肤病学 | 51024篇 |
神经病学 | 209721篇 |
特种医学 | 98194篇 |
外国民族医学 | 886篇 |
外科学 | 371853篇 |
综合类 | 56764篇 |
现状与发展 | 1篇 |
一般理论 | 998篇 |
预防医学 | 205114篇 |
眼科学 | 58205篇 |
药学 | 186235篇 |
4篇 | |
中国医学 | 4860篇 |
肿瘤学 | 130787篇 |
出版年
2018年 | 28043篇 |
2017年 | 21178篇 |
2016年 | 22944篇 |
2015年 | 25955篇 |
2014年 | 36472篇 |
2013年 | 55191篇 |
2012年 | 76477篇 |
2011年 | 80395篇 |
2010年 | 46412篇 |
2009年 | 43743篇 |
2008年 | 75168篇 |
2007年 | 79874篇 |
2006年 | 80396篇 |
2005年 | 78090篇 |
2004年 | 74800篇 |
2003年 | 71972篇 |
2002年 | 70917篇 |
2001年 | 114297篇 |
2000年 | 118568篇 |
1999年 | 99922篇 |
1998年 | 28233篇 |
1997年 | 25753篇 |
1996年 | 25663篇 |
1995年 | 24810篇 |
1994年 | 23322篇 |
1993年 | 21709篇 |
1992年 | 80353篇 |
1991年 | 77252篇 |
1990年 | 74486篇 |
1989年 | 71644篇 |
1988年 | 66589篇 |
1987年 | 65515篇 |
1986年 | 62153篇 |
1985年 | 59108篇 |
1984年 | 44767篇 |
1983年 | 38140篇 |
1982年 | 23140篇 |
1981年 | 20560篇 |
1979年 | 41974篇 |
1978年 | 29433篇 |
1977年 | 24802篇 |
1976年 | 23239篇 |
1975年 | 24457篇 |
1974年 | 30305篇 |
1973年 | 28766篇 |
1972年 | 26878篇 |
1971年 | 24801篇 |
1970年 | 23358篇 |
1969年 | 21735篇 |
1968年 | 19801篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
A. Heinig S. H. Heywang-Köbrunner P. Viehweg D. Lampe J. Buchmann R. P. Spielmann 《Der Radiologe》1997,37(9):710-717
Summary
Early recognition of recurrence and work-up of clinically indeterminate lesions may be impaired after reconstruction with
silicone implants due to superimposition of the implant or to scarring. This study was undertaken to evaluate the use of contrast-enhanced
MRI in patients with silicone implant after breast cancer. Contrast-enhanded MRI was offered to 169 patients. Comparative
two- to three-view mammography was also performed in 169 patients, as well as comparative sonography in 144 patients. Conventional
imaging and clinical examination detected only 8/13 recurrences, whereas 12/13 were detected by MRI. One recurrence had been
visible as a strongly enhancing 2-mm dot in a previous examination (2 years before), but was not called. It was therefore
counted as false negative. In addition, multicentricity was detected by MRI alone in two of three cases. MRI correctly diagnosed
scar tissue in all cases with indeterminate findings. However, due to false-positive calls caused by enhancing granulomas
specificity could not be improved. Contrast-enhanded MRI allowed decisive additional information in our study group and improved
the sensitivity significantly (concerning all diagnoses). Contrast-enhanded MRI is recommended in patients with diagnostic
problems or high risk of recurrence after silicone implants.
相似文献
994.
995.
降糖饮降糖作用的实验研究 总被引:2,自引:0,他引:2
降糖饮以8.1,15.0,30。0g.kg^-1灌胃予鼠,连续10天。结果表明降饮对正常小鼠大鼠血糖血脂无明显影响,但对四氧嘧啶或链脲霉素引起的大鼠高血糖及蛋黄引起的小鼠高脂血症,高胆固醇饲料引起的大鼠高脂血症均有显著降低作用。本研究为降糖饮的应用提供了可靠的药理学依据。 相似文献
996.
Is colonic electrical activity a similar phenomena to small-bowel electrical activity? 总被引:4,自引:0,他引:4
Dr. José A. S. Medeiros M.D. Ph.D. Fausto A. Pontes M.D. Ph.D. Octávio A. R. O. Mesquita 《Diseases of the colon and rectum》1997,40(1):93-99
PURPOSE: This study was designed to investigate colonic spike bursts regarding 1) their migration behavior, 2) their pressure correlates, and 3) comparing colonic short spike bursts with spike bursts from migrating myoelectric complex from the small bowel. METHODS: Rectosigmoid electromyography and manometry were recorded simultaneously in seven normal volunteers and electromyography alone in five others during two hours of fasting and for two hours after one 2,100-kJ meal. One patient with an ileostomy was also studied by the same method to record the migrating myoelectric complex from the terminal ileum during fasting. RESULTS: Three kinds of spike bursts were observed in the pelvic colon: rhythmic short spike bursts, migrating long spike bursts, and nonmigrating long spike bursts. The meal significantly increased the number of migrating and nonmigrating long spike bursts (from 25 to 38.7 percent of the recording time;
P
<0.01). These bursts of potentials showed a peak 15 minutes after the meal, which may be caused by the gastrocolic reflex. Migrating long spike bursts started anywhere along the rectosigmoid and migrated from there aborad 82 percent of the time and orad or in both directions in 10 or 7 percent of the time, respectively. They originated pressure waves 99 percent of the time. Short spike bursts were more frequent before the meal (15.1 percent before and 9.6 percent after the meal), but the difference was not significant; they neither propagated nor initiated pressure waves detected by the miniballoon. CONCLUSIONS: Migrating long spike bursts were the only potentials that migrated, sometimes for short distances. Short spike bursts are a different phenomenon from the small-bowel migrating myoelectric complex because they do not migrate; they can occur during the postprandial period and never originated intraluminal pressure waves.Supported by a grant from the Instituto Nacional de Investigação Científica, Proc. DBI-22086.Presented at the meeting of the Portuguese Congress of Gastrenterology, Vila Moura, Portugal, June 2 to 5, 1993. 相似文献
997.
Conditionally replicating luciferase reporter phages: improved sensitivity for rapid detection and assessment of drug susceptibility of Mycobacterium tuberculosis. 总被引:7,自引:1,他引:6
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)
C Carrire P F Riska O Zimhony J Kriakov S Bardarov J Burns J Chan W R Jacobs Jr 《Journal of clinical microbiology》1997,35(12):3232-3239
TM4 is a lytic mycobacteriophage which infects mycobacteria of clinical importance. A luciferase reporter phage, phAE40, has been constructed from TM4 and was previously shown to be useful for the rapid detection and drug susceptibility testing of Mycobacterium tuberculosis. However, the lytic nature of the phage results in a loss of detectable light output and limits the sensitivity of detection. We describe several strategies aimed at improving the luciferase activity generated by TM4 luciferase phages, including (i) varying the position of the luciferase gene in the phage genome, (ii) isolating host-range mutants of the phage, and (iii) introducing temperature-sensitive mutations in the phage such that it will not replicate at the infecting temperature. Several new phages generated by these methods show increased intensity of luciferase production compared to the first-generation reporter phage phAE40, and one phage, phAE88, also demonstrates an enhanced duration of luciferase activity. This has allowed the detection of as few as 120 BCG cells and the determination of drug susceptibilities of M. tuberculosis in as little as 1 day. 相似文献
998.
Oral allergy syndrome induced by spinach 总被引:1,自引:1,他引:0
I. Sanchez F. Rodriguez J. L. Garcia-Abujeta L. Fernandez D. Quiñones D. Martin-Gil 《Allergy》1997,52(12):1245-1246
999.
AIMS: Immunohistological and molecular characterisation of a case of peripheral T-cell lymphoma (PTCL) of angioimmunoblastic T-cell lymphoma (AILD) type. METHODS: Frozen and paraffin wax sections of the diagnostic lymph node were stained with a panel of T- and B-cell lineage monoclonal antibodies. DNA was isolated from the paraffin wax embedded biopsy material for T-cell receptor (TCR) and immunoglobulin (Ig) PCR amplification, and resultant PCR products were cloned and sequenced. RESULTS: Immunohistological analysis of the presenting lymph node was consistent with an extensive infiltrate of pleomorphic CD3+CD8+ lymphocytes. Most (>80%) of these infiltrating CD3+ cells were also positive for the TCR VB5.1 gene family product, and were shown to be oligoclonal by TCRB PCR amplification and sequencing. Three oligoclones of B cells were also demonstrable by PCR amplification with Ig heavy chain primers and sequencing, a finding at variance with the diagnosis of AILD. CONCLUSIONS: These data demonstrate the complexity and heterogeneity of PTCL which require extensive histological examination and molecular characterisation. 相似文献
1000.
Antigenicity of a synthetic peptide from glucosyltransferases of Streptococcus mutans in humans. 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Human salivary immunoglobulin A (IgA) and serum IgG antibodies to the Streptococcus mutans glucosyltransferases (Gtfs) and to a synthetic peptide of 19 amino acids from a conserved region in the Gtfs (residues 435 to 453) were determined in young adults by enzyme-linked immunosorbent assay. Varying levels of antibody to Gtfs were detected in saliva or serum, with significantly higher levels of antibody to GtfD than to GtfB/C or GtfC. Anti-Gtf IgA levels in saliva did not correlate with those of IgG in serum. Caries-free (CF) volunteers exhibited significantly higher salivary IgA antibody levels to the peptide and to GtfB/C or GtfC than did the caries-active (CA) subjects. Preincubation of CF saliva and serum with the peptide inhibited the antibodies to the Gtfs in a dose-dependent manner, whereas preincubation of the samples from the CA group resulted in only partial inhibition. Our results indicated that this 19-amino-acid peptide includes one of the major B-cell epitopes of Gtfs and that CF individuals have higher titers of antibodies than CA subjects. 相似文献