全文获取类型
收费全文 | 4714篇 |
免费 | 263篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 123篇 |
妇产科学 | 54篇 |
基础医学 | 931篇 |
口腔科学 | 87篇 |
临床医学 | 346篇 |
内科学 | 879篇 |
皮肤病学 | 85篇 |
神经病学 | 442篇 |
特种医学 | 250篇 |
外科学 | 648篇 |
综合类 | 24篇 |
一般理论 | 1篇 |
预防医学 | 262篇 |
眼科学 | 129篇 |
药学 | 414篇 |
中国医学 | 4篇 |
肿瘤学 | 273篇 |
出版年
2022年 | 23篇 |
2021年 | 70篇 |
2020年 | 35篇 |
2019年 | 52篇 |
2018年 | 75篇 |
2017年 | 60篇 |
2016年 | 67篇 |
2015年 | 93篇 |
2014年 | 119篇 |
2013年 | 133篇 |
2012年 | 256篇 |
2011年 | 245篇 |
2010年 | 145篇 |
2009年 | 137篇 |
2008年 | 213篇 |
2007年 | 253篇 |
2006年 | 234篇 |
2005年 | 255篇 |
2004年 | 259篇 |
2003年 | 267篇 |
2002年 | 249篇 |
2001年 | 102篇 |
2000年 | 78篇 |
1999年 | 80篇 |
1998年 | 82篇 |
1997年 | 58篇 |
1996年 | 50篇 |
1995年 | 52篇 |
1994年 | 44篇 |
1993年 | 47篇 |
1992年 | 65篇 |
1991年 | 47篇 |
1990年 | 59篇 |
1989年 | 60篇 |
1988年 | 44篇 |
1987年 | 36篇 |
1986年 | 60篇 |
1985年 | 45篇 |
1984年 | 46篇 |
1983年 | 28篇 |
1982年 | 37篇 |
1981年 | 31篇 |
1980年 | 42篇 |
1979年 | 45篇 |
1978年 | 23篇 |
1977年 | 31篇 |
1976年 | 36篇 |
1975年 | 24篇 |
1973年 | 34篇 |
1969年 | 22篇 |
排序方式: 共有4985条查询结果,搜索用时 265 毫秒
31.
Management of sacral and perineal defects following abdominoperineal resection and radiation with transpelvic muscle flaps 总被引:6,自引:2,他引:4
Scott J. Loessin M.D. Dr. N. Bradly Meland M.D. Richard M. Devine M.D. Bruce G. Wolff M.D. Heidi Nelson M.D. Horst Zincke M.D. 《Diseases of the colon and rectum》1995,38(9):940-945
PURPOSES: In this study we present our experience with treating persistent sacral and perineal defects secondary to radiation and abdominoperineal resection with or without sacrectomy. METHODS: Fifteen consecutive patients were treated with an inferiorly based transpelvic rectus abdominis muscle or musculocutaneous flap. RESULTS: Fourteen of the 15 patients achieved healing, and 7 patients had no complications. The remaining eight patients required one or more operative debridements and/or prolonged wound care to accomplish a healed wound. Our technique for the dissection and insetting of the transpelvic muscle flap is presented. CONCLUSION: The difficult postirradiated perineal and sacral wounds can be healed with persistent surgical attention to adequate debridement, control of infections, and a well-vascularized muscle flap. The most satisfying aspects for patients are the discontinuance of foul-smelling discharge, discontinuation of multiple, daily dressing changes, and reduction in the degree of chronic pain.Read at the meeting of the Midwestern Association of Plastic Surgeons, Bismarck, North Dakota, June 15 to 18, 1992. 相似文献
32.
Marion Jung EvaMaria Krämer Thomas Müller Horst Antonicek Jacqueline Trotter 《The European journal of neuroscience》1998,10(10):3246-3256
The immortalization of progenitor cells from embryonic murine hippocampus using oncogene‐carrying retroviral vectors is described. Use of a vector encoding the oncogene v‐myc results in lines of nestin‐positive progenitor cells. Limited differentiation ensues if the cells are cultured in the presence of dibutyryl cyclic adenosine monophosphate. In contrast, use of a vector in which the extracellular portion of the epidermal growth factor (EGF) receptor is fused to the neu tyrosine kinase generates lines of pluripotential nestin‐positive progenitor cells, which differentiate upon withdrawal of EGF into neurons and glia. Differentiated neurons expressing action potentials and neurotransmitter receptors make up a high proportion of the cells. These cell lines are useful tools to investigate the characteristics of differentiating neurons and glia, as well as to screen neuroactive drugs. This work has been reported in preliminary form as an abstract (1996 Society for Neuroscience Abstract, #606.20, p. 1537). 相似文献
33.
Four hundred and fifty dental graduates from the Free University (VU), the University of Amsterdam (UvA) or the Academic Center for Dentistry Amsterdam (ACTA) between 1982 and 1990 were asked by questionnaire to give their opinion about the undergraduate dental training they received. Most respondents felt that their undergraduate education prepared them reasonably well for general practice. Yet imperfections in the education were noticed. These imperfections show resemblance to conclusions from similar surveys in other countries. 相似文献
34.
Horst Friebolin Norbert Frank Gunda Keilich Egon Siefert 《Macromolecular chemistry and physics.》1976,177(3):845-858
The 13C-NMR spectra of malto- and isomalto-oligosaccharides, amylose and dextrane were analysed. It was observed that in both series of oligosaccharides and polysaccharides the resonances of the central glucose units are independent of the chain length with the exception of the C-atoms 1 and 4 of amylose which show deviations of 0,4 and 0,5 ppm. These small effects can possibly be explained by a definite polysaccharide chain conformation in solution. 相似文献
35.
PAX6 is a candidate gene for familial aniridia. We have carried out a mutational analysis of the PAX6 gene in a three-generation family from Germany, containing 5 individuals affected with ocular abnormalities. In all affected individuals, a heterozygous mutation was detected in the PAX6 gene, exchanging tyrosine 369 by a stop codon. The mutation is located in the 3' moiety of the PST domain, at the C terminus of the PAX6 protein. In the affected family members, the same heterozygous mutation leads to distinct phenotypes of varying severity. Most notably, no aniridia was observed in one of the family members carrying the mutation, although other ocular abnormalities (underdeveloped iris and cataracts) were present. We discuss the possibility that small C terminal truncations of the PAX6 protein might lead to less severe or more divergent phenotypes than trancations at internal positions. 相似文献
36.
Blinded, Externally Controlled Multicenter Evaluation of Light Microscopy and PCR for Detection of Microsporidia in Stool Specimens 总被引:6,自引:4,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)
Heinz Rinder Klaus Janitschke Horst Aspck Alexandre J. Da Silva Peter Deplazes Daniel P. Fedorko Caspar Franzen Ursula Futh Frank Hünger Anselm Lehmacher Christian G. Meyer Jean-Michel Molina Jrg Sandfort Rainer Weber Thomas Lscher the Diagnostic Multicenter Study Group on Microsporidia 《Journal of clinical microbiology》1998,36(6):1814-1818
The quality parameters for the detection of microsporidia in identical sets of 50 stool samples were determined for six laboratories where technicians used light microscopy and for six laboratories where technicians used PCR. The average overall sensitivities were 67% (89% for patient samples only) for the PCR laboratories and 54% (80% for patient samples only) for the light microscopy laboratories. Specificities were 98 and 95%, respectively. Differences in results were most apparent between the individual laboratories rather than between the two major methods used. 相似文献
37.
Werner M Mattis A Aubele M Cummings M Zitzelsberger H Hutzler P Höfler H 《Virchows Archiv : an international journal of pathology》1999,435(5):469-472
The 20q13 region harboring recently described putative oncogenes is frequently amplified in invasive ductal carcinoma (IDC).
The aim of this study was to examine the 20q13 copy number in intraduct hyperplasia (IH), atypical duct hyperplasia (ADH),
and ductal carcinoma in situ (DCIS) adjacent to IDC. In 5 patients, comparative genomic hybridization (CGH) after laser microdissection
revealed 20q13 amplification in four of five cases of IH, in all of three cases of IH with atypia, all five of DCIS, and all
five of IDC. Fluorescence in situ hybridization (FISH) confirmed the amplification at 20q13.2 in IH in the two specimens analyzed.
The amplification rate, however, was higher in DCIS and IDC. In phenotypically normal ductal epithelium normal values were
found for 20q13 copy number by FISH (n=2) and CGH (n=5). Although the number of cases presented here is small, our results suggest that mutations in the 20q13.2 region in IH
may be associated with accelerated proliferation and hyperplasia of the ductal epithelium. Progression to DCIS and ICD is
accompanied by a further increase in the 20q13.2 copy number.
Received: 17 March 1999 / Accepted: 22 June 1999 相似文献
38.
Krücken J Dkhil MA Braun JV Schroetel RM El-Khadragy M Carmeliet P Mossmann H Wunderlich F 《Infection and immunity》2005,73(1):436-443
Testosterone induces a lethal outcome in otherwise self-healing blood-stage malaria caused by Plasmodium chabaudi. Here, we examine possible testosterone effects on the antimalaria effectors spleen and liver in female C57BL/6 mice. Self-healing malaria activates gating mechanisms in the spleen and liver that lead to a dramatic reduction in trapping activity, as measured by quantifying the uptake of 3-mum-diameter fluorescent polystyrol particles. However, testosterone delays malaria-induced closing of the liver, but not the spleen. Coincidently, testosterone causes an approximately 3- to 28-fold depression of the mRNA levels of nine malaria-responsive genes, out of 299 genes tested, only in the liver and not in the spleen, as shown by cDNA arrays and Northern blotting. Among these are the genes encoding plasminogen activator inhibitor (PAI1) and hydroxysteroid sulfotransferase (STA2). STA2, which detoxifies bile acids, is suppressed 10-fold by malaria and an additional 28-fold by testosterone, suggesting a severe perturbation of bile acid metabolism. PAI1 is protective against malaria, since disruption of the PAI1 gene results in partial loss of the ability to control the course of P. chabaudi infections. Collectively, our data indicate that the liver rather than the spleen is a major target organ for testosterone-mediated suppression of resistance against blood-stage malaria. 相似文献
39.
Silent mutations in the phenylalanine hydroxylase gene as an aid to the diagnosis of phenylketonuria.
下载免费PDF全文
![点击此处可从《Journal of medical genetics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
L Kalaydjieva B Dworniczak C Aulehla-Scholz M Devoto G Romeo M Sturhmann V Kucinskas V Yurgelyavicius J Horst 《Journal of medical genetics》1991,28(10):686-690
Direct sequencing of the phenylalanine hydroxylase (PAH) gene indicated the existence of silent mutations in codons 232, 245, and 385, linked to specific RFLP haplotypes in several Caucasian populations, namely Germans, Bulgarians, Italians, Turks, and Lithuanians. All three mutations create a new restriction site and can be easily detected on PCR amplified DNA. The usefulness of the silent mutations for diagnostic purposes depends on the haplotype distribution in the target population. The combined analysis of these markers and one or two PKU mutations forms a simple panel of diagnostic tests with full informativeness in a large proportion of PKU families, which helps to avoid the problems of genetic heterogeneity and of prenatal genomic Southern blot analysis. 相似文献
40.
Nadja Bogdanova Beate Lemcke Arseni Markoff Hartmut Pollmann Bernd Dworniczak Antonin Eigel Jürgen Horst 《Human mutation》2001,18(6):546-546
Haemophilia A is a X‐linked bleeding disorder, caused by deficiency in the activity of coagulation factor VIII due to mutations in the corresponding gene. The most common defect in patients is an inversion of the factor VIII gene that accounts for nearly 45% of individuals with severe hemophilia A. Point mutations and small deletions/insertions are responsible for the majority of cases with moderate to mild clinical course and for half of the severe hemophilia A occurrences. The majority of these mutations are “private”, because of the high mutation rate for this particular gene. We report on eleven pathological changes in the factor VIII sequence detected in male patients with haemophilia A or in female obligate carriers. Seven of these mutations are novel [E204N, E265X, M320T, F436C, S535C, N2129M and R2307P] and four have been previously identified [V162M, R527W, R1966X, and R2159C]. Genotype‐phenotype correlations and computer prediction analysis on the effect of missense mutations on the secondary structure of the factor VIII protein are performed and the relationships evaluated. © 2001 Wiley‐Liss, Inc. 相似文献