全文获取类型
收费全文 | 1557篇 |
免费 | 71篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 50篇 |
妇产科学 | 59篇 |
基础医学 | 159篇 |
口腔科学 | 25篇 |
临床医学 | 178篇 |
内科学 | 254篇 |
皮肤病学 | 30篇 |
神经病学 | 154篇 |
特种医学 | 166篇 |
外科学 | 231篇 |
综合类 | 8篇 |
预防医学 | 87篇 |
眼科学 | 12篇 |
药学 | 156篇 |
中国医学 | 3篇 |
肿瘤学 | 67篇 |
出版年
2022年 | 9篇 |
2021年 | 17篇 |
2020年 | 12篇 |
2019年 | 17篇 |
2018年 | 14篇 |
2017年 | 10篇 |
2016年 | 21篇 |
2015年 | 32篇 |
2014年 | 26篇 |
2013年 | 52篇 |
2012年 | 61篇 |
2011年 | 50篇 |
2010年 | 45篇 |
2009年 | 50篇 |
2008年 | 61篇 |
2007年 | 68篇 |
2006年 | 56篇 |
2005年 | 54篇 |
2004年 | 60篇 |
2003年 | 66篇 |
2002年 | 57篇 |
2001年 | 48篇 |
2000年 | 79篇 |
1999年 | 51篇 |
1998年 | 46篇 |
1997年 | 58篇 |
1996年 | 38篇 |
1995年 | 33篇 |
1994年 | 25篇 |
1993年 | 21篇 |
1992年 | 37篇 |
1991年 | 21篇 |
1990年 | 30篇 |
1989年 | 33篇 |
1988年 | 45篇 |
1987年 | 32篇 |
1986年 | 25篇 |
1985年 | 24篇 |
1984年 | 15篇 |
1983年 | 29篇 |
1982年 | 15篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1978年 | 9篇 |
1977年 | 13篇 |
1976年 | 11篇 |
1974年 | 5篇 |
1973年 | 8篇 |
1971年 | 5篇 |
排序方式: 共有1643条查询结果,搜索用时 15 毫秒
51.
A comparison of Skirrow's, Butzler's, Blaser's, Campy-BAP and Preston media for Campylobacter spp was made using human, animal and environmental specimens. Butzler's medium gave the lowest isolation rate and Preston medium, which was the most selective, the highest isolation rate. Enrichment culture using Preston enrichment broth gave a higher isolation rate than direct plating onto Preston medium. 相似文献
52.
Ljubisa Borota Christoffer Nyberg Samuel Lenell Robert Semnic Ehab Mahmoud 《Interventional neuroradiology》2021,27(3):372
Aim of the studyThe aim of this study was to evaluate our results regarding treatment options, complications, and outcomes in patients with non-saccular aneurysms of cerebral arteries belonging to type 1 and type 4 according to Mizutani’s classification.MethodsA total of 26 aneurysms in 26 patients were treated between 2014 and 2019. There were 13 males (mean age 42.77 ± 11.73 years) and 13 females (mean age 50.84 ± 9.37 years). In 23 cases the onset was haemorrhagic and in three cases non-haemorrhagic. A combination of conventional stents and coils was used in 10 cases, conventional stents and flow diverters in three cases, flow diverters and coils in five cases, and flow diverters only were used in eight cases. Radiological results of treatment were assessed after eight months and clinical after one year.ResultsIn 24 patients, aneurysms were occluded at the end of the follow-up period. An iatrogenic dissection and two haemorrhagic complications were registered. In three cases, parent arteries were occluded due to re-growth of the aneurysm, which caused middle cerebral artery infarction in one case. A favourable clinical outcome was registered in 19, patients, and non-favourable in five. Two patients died in the early postoperative period due to extensive damage to the brain parenchyma caused by initial bleeding.ConclusionOur results indicate that treatment of type 1 and type 4 non-saccular aneurysms with various combination of stents and flow diverters, with or without coils, is promising, although very challenging and technically demanding. 相似文献
53.
Marsman H Matsushita T Dierkhising R Kremers W Rosen C Burgart L Nyberg SL 《Human pathology》2004,35(4):430-435
Steatosis in donor liver biopsy specimens has been shown to correlate with graft dysfunction after orthotopic liver transplantation. This 2-part (laboratory pilot, clinical retrospective) study compared the traditional interpretation of steatosis by a pathologist with an automated measurement determined by an image analysis system. In our pilot study, Sprague-Dawley rats were studied prospectively by feeding them a choline-deficient diet for up to 7 days. In our clinical group, data from 49 consecutive recipients of cadaveric liver transplantation were reviewed retrospectively. In both studies, the percentages of microvesicular fat, macrovesicular fat, and total fat content within liver biopsy specimens were determined by an automated image analysis software program and a pathologist using the same set of slides. The association between fat content of the donor liver and patient survival and graft survival, along with levels of aspartate aminotransferase, alanine aminotransferase, prothrombin time, and total bilirubin after transplantation, were also examined in the clinical study. A direct correlation was observed between levels of macrovesicular fat determined by a pathologist and the automated software using livers from rats fed a choline-deficient diet and livers from deceased donors. A significant association was observed between macrovesicular fat content in the donor liver biopsy and graft survival by both techniques. We conclude that an image analysis system can be used to automate the determination of fat content in liver biopsy specimens, and that its findings correlate with both the visual interpretation by a pathologist and graft survival. Further study is needed to determine the role of an automated technique in the evaluation of donor livers for transplantation. 相似文献
54.
AMJ van Wegberg RAF Evers JGM Burgerhof E van Dam M.R. Heiner-Fokkema MCH Janssen MC de Vries FJ van Spronsen 《Molecular genetics and metabolism》2021,132(1):49-55
BackgroundIn patients with phenylketonuria, stability of blood phenylalanine and tyrosine concentrations might influence brain chemistry and therefore patient outcome. This study prospectively investigated the effects of tetrahydrobiopterin (BH4), as a chaperone of phenylalanine hydroxylase on diurnal and day-to-day variations of blood phenylalanine and tyrosine concentrations.MethodsBlood phenylalanine and tyrosine were measured in dried blood spots (DBS) four times daily for 2 days (fasting, before lunch, before dinner, evening) and once daily (fasting) for 6 days in a randomized cross-over design with a period with BH4 and a period without BH4. The sequence was randomized. Eleven proven BH4 responsive PKU patients participated, 5 of them used protein substitutes during BH4 treatment. Natural protein intake and protein substitute dosing was adjusted during the period without BH4 in order to keep DBS phenylalanine levels within target range. Patients filled out a 3-day food diary during both study periods. Variations of DBS phenylalanine and Tyr were expressed in standard deviations (SD) and coefficient of variation (CV).ResultsBH4 treatment did not significantly influence day-to-day phenylalanine and tyrosine variations nor diurnal phenylalanine variations, but decreased diurnal tyrosine variations (median SD 17.6 μmol/l, median CV 21.3%, p = 0.01) compared to diet only (median SD 34.2 μmol/l, median CV 43.2%). Consequently, during BH4 treatment diurnal phenylalanine/tyrosine ratio variation was smaller, while fasting tyrosine levels tended to be higher.ConclusionBH4 did not impact phenylalanine variation but decreased diurnal tyrosine and phenylalanine/tyrosine ratio variations, possibly explained by less use of protein substitute and increased tyrosine synthesis. 相似文献
55.
Schlussman SD Zhou Y Johansson P Kiuru A Ho A Nyberg F Kreek MJ 《Neuroscience letters》2000,284(3):190-194
There is increasing abuse of androgenic anabolic steroids (AAS) by non-athletes. AAS abuse has been associated with psychiatric symptoms such as mania, major depression and aggression and the development of dependence. Little is known about the effects of AAS on hypothalamic-pituitary-adrenal axis function or corticotropin releasing factor, which may be involved in mediating some of the psychiatric symptoms associated with AAS abuse. Male Sprague-Dawley rats received one daily intra-muscular injection of the AAS nandrolone decanoate (ND, 15 mg/kg) or vehicle for 3 days. Animals were sacrificed either 1 h or 24 h after the last injection, brain regions dissected and trunk blood collected. Corticotropin releasing factor (CRF), CRF receptor1 (CRF-R1) and proopiomelanocortin (POMC) mRNAs were measured with solution hybridization/RNase protection. Circulating levels of corticosterone and adrenocorticotropin hormone (ACTH) were determined using radioimmunoassays. One hour following the last injection, ND significantly increased circulating levels of both corticosterone and ACTH levels. In the amygdala, CRF mRNA levels were unchanged 1 h after the last injection of ND but were significantly reduced at 24 h. The same was found for hypothalamic POMC. No significant AAS effects were observed on: hypothalamic CRF mRNA; POMC mRNA in the amygdala or CRF R1 mRNA in the anterior pituitary. 相似文献
56.
Short DNA sequences and bacterial DNA induce esophageal,gastric, and colorectal cancer cell invasion
Joonas H. Kauppila Tuomo J. Karttunen Juha Saarnio Pia Nyberg Tuula Salo David E. Graves Katri S. Selander 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2013,121(6):511-522
Toll‐like receptor 9 (TLR9) recognizes both bacterial and self‐DNA and it is abundantly expressed in the gastrointestinal tract. In this study, we investigated the influences of both bacterial DNA and specific short DNA sequences on TLR9‐mediated gastrointestinal cancer cell invasion. We assessed the effect of various DNA ligands on cellular invasion and on TLR9 and matrix metalloproteinase expression of three gastrointestinal cancer cell lines. DNA‐ligands described in this study include CpG‐ODN M362, 9‐mer (hairpin), human telomeric sequence h‐Tel22 G‐quadruplex, and bacterial DNAs from Escherichia coli and Helicobacter pylori. All of the DNAs studied were demonstrated to induce invasion in the studied cells. The DNA‐induced invasion was inhibited with a broad‐spectrum MMP inhibitor and partly also with chloroquine suggesting that it could be mediated via MMP activation, endosomal signaling, and TLR9. Interestingly, H. pylori DNA was shown to induce a more pronounced invasion in a gastric cancer cell line than in the other cell lines. Our results suggest that bacterial DNA as well as deoxynucleotides having stable secondary structures (i.e. hairpins or G‐quadruplex structures) may serve as endogenous, invasion‐inducing TLR9‐ligands and promote local progression and metastasis of cancers in the alimentary tract. 相似文献
57.
Frataxin is reduced in Friedreich ataxia patients and is associated with mitochondrial membranes 总被引:17,自引:8,他引:17
Campuzano V; Montermini L; Lutz Y; Cova L; Hindelang C; Jiralerspong S; Trottier Y; Kish SJ; Faucheux B; Trouillas P; Authier FJ; Durr A; Mandel JL; Vescovi A; Pandolfo M; Koenig M 《Human molecular genetics》1997,6(11):1771-1780
Friedreich ataxia is a progressive neurodegenerative disorder caused by
loss of function mutations in the frataxin gene. In order to unravel
frataxin function we developed monoclonal antibodies raised against
different regions of the protein. These antibodies detect a processed 18
kDa protein in various human and mouse tissues and cell lines that is
severely reduced in Friedreich ataxia patients. By immunocytofluorescence
and immunocytoelectron microscopy we show that frataxin is located in
mitochondria, associated with the mitochondrial membranes and crests.
Analysis of cellular localization of various truncated forms of frataxin
expressed in cultured cells and evidence of removal of an N-terminal
epitope during protein maturation demonstrated that the mitochondrial
targetting sequence is encoded by the first 20 amino acids. Given the
shared clinical features between Friedreich ataxia, vitamin E deficiency
and some mitochondriopathies, our data suggest that a reduction in frataxin
results in oxidative damage.
相似文献
58.
In the present study we compared genetically selected aggressive (TA) and nonaggressive (TNA) male mice, as well as males from an unselected control line (SW), in three tests of anxiety: the elevated plus-maze, the light-dark box, and the staircase test. Males were tested repeatedly for 3 days. In all three tests TA males were found to be more active and less anxious than TNA males, with SW males showing more or less intermediate scores. Furthermore, repeated plus-maze testing induced anxiety-like behavior in both TA and TNA mice, whereas repeated testing in the light-dark and staircase paradigms resulted in different responses. Whereas TNA animals were found to be stable, TA animals showed habituation on the second and third day of testing. The obtained data support the conclusion that a higher-level offensive aggression entails lower level of anxiety. 相似文献
59.
IA Maartens T Wassenberg FJ Halbertsma HAM Marres P Andriessen 《Acta paediatrica (Oslo, Norway : 1992)》2009,98(11):1852-1854
A case report is presented of a rapidly growing congenital nasopharyngeal teratoma (epignathus) in a preterm infant, leading to severe upper airway obstruction. Prenatal diagnosis by ultrasonography did not reveal the condition because the tumour masses were initially small and there was no polyhydramnios. Epignathus is a rare cause of upper airway obstruction of the newborn that can grow rapidly in the neonatal period and should be treated surgically.
Conclusion: Epignathus is a rare cause of upper airway obstruction of the newborn that can grow rapidly in the neonatal period. 相似文献
Conclusion: Epignathus is a rare cause of upper airway obstruction of the newborn that can grow rapidly in the neonatal period. 相似文献
60.
BD Heckman KA Holroyd G Tietjen FJ O'Donnell L Himawan C Utley R Watakakosol & M Stillman 《Cephalalgia : an international journal of headache》2009,29(6):650-661
This study sought to determine if Whites and African-Americans respond similarly to headache treatment administered in 'real-world' headache specialty treatment clinics. Using a naturalistic, longitudinal design, 284 patients receiving treatment for headache disorders completed 30-day daily diaries that assessed headache frequency and severity at pretreatment and 6-month follow-up and also provided data on their headache disability and quality of life at pretreatment and 1-, 2- and 6-month follow-up. Controlling for socioeconomic status and psychiatric comorbidity, hierarchical linear models found that African-Americans and Whites reported significant reductions in headache frequency and disability and improvements in life quality over the 6-month treatment period. African-Americans, unlike Whites, also reported significant decreases in headache severity. Nevertheless, Africans-Americans had significantly more frequent and disabling headaches and lower quality of life after treatment relative to Whites. Although Whites and African Americans responded favourably to headache treatments, more efficacious treatments are needed given the elevated level of headache frequency that remained in both racial groups following treatment. 相似文献