全文获取类型
收费全文 | 270篇 |
免费 | 23篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 6篇 |
妇产科学 | 4篇 |
基础医学 | 25篇 |
口腔科学 | 2篇 |
临床医学 | 31篇 |
内科学 | 51篇 |
皮肤病学 | 2篇 |
神经病学 | 35篇 |
特种医学 | 8篇 |
外科学 | 37篇 |
综合类 | 1篇 |
预防医学 | 12篇 |
眼科学 | 18篇 |
药学 | 39篇 |
肿瘤学 | 22篇 |
出版年
2023年 | 2篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 3篇 |
2017年 | 8篇 |
2016年 | 5篇 |
2015年 | 11篇 |
2014年 | 8篇 |
2013年 | 19篇 |
2012年 | 12篇 |
2011年 | 17篇 |
2010年 | 7篇 |
2009年 | 6篇 |
2008年 | 14篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 12篇 |
2004年 | 10篇 |
2003年 | 11篇 |
2002年 | 8篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1992年 | 3篇 |
1991年 | 8篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1976年 | 3篇 |
1973年 | 3篇 |
1970年 | 2篇 |
1956年 | 1篇 |
1942年 | 1篇 |
1939年 | 1篇 |
1881年 | 2篇 |
1870年 | 2篇 |
1869年 | 1篇 |
1864年 | 1篇 |
1861年 | 1篇 |
排序方式: 共有297条查询结果,搜索用时 15 毫秒
1.
2.
The atoxic binding fragment of tetanus toxin, Fragment C, was injected into paravertebral ganglion 14, the avian homologue of the mammalian stellate ganglion. Postinjection survival intervals were varied from 2.5 h to 33 days. Experiments performed at the shortest survival time of 2.5 h showed that Fragment C was retrogradely transported by sympathetic preganglionic axons at a rate greater than or equal to 10 mm/h. At survival times ranging from 5 to 15 h. Fragment C-positive, retrogradely labeled sympathetic preganglionic neurons were observed within the last cervical spinal segment and throughout the first three thoracic spinal cord segments. Sporadic retrograde labeling of sympathetic preganglionic neurons was evident within the fourth and fifth thoracic spinal cord segments. Fragment C-labeled perikarya and dendrites exhibited both diffuse cytoplasmic immunostaining as well as intracellular, perinuclear accumulations of small. Fragment C-positive granules. Retrogradely labeled preganglionic neurons were found within both autonomic subnuclei within avian thoracic spinal cord; the column of Terni and the nucleus intercalatus spinalis. The distribution and numerical density of retrogradely labeled sympathetic preganglionic neurons indicated further that: (a) both myelinated and unmyelinated preganglionic axons appear to be capable of intra-axonally transporting Fragment C; and (b) it is unlikely that there is differential Fragment C labeling of a morphologically distinct population of sympathetic preganglionic neurons within or across subnuclei. Fragment C is transferred out of sympathetic preganglionic somas and dendrites into the surrounding neuropil at an aggregate rate greater than or equal to 5 mm/h. Trans-synaptic transport was evident at postinjection survival times as short as 5 h and continued to increase in density within the sympathetic preganglionic neuropil for 24 h. Fragment C-positive terminal labeling persisted for at least 20 days. At survival times greater than or equal to 1 day. Fragment C-positive puncta and weak intracellular labeling of neurons were evident in areas of the spinal gray outside of the nuclear boundaries of the column of Terni and nucleus intercalatus. The regions showing evidence of trans-synaptic and transneuronal labeling included: (a) a group of small cells dorsal to the column of Terni, (b) lamina V and (c) lamina VII. This expansion of Fragment C-labeled neuronal elements was segmental in organization and co-extensive with the retrograde labeling pattern of sympathetic preganglionic neurons. Spinal interneurons in these regions may provide segmental, monosynaptic input to sympathetic preganglionic neurons. Fragment C leaked into the systemic circulation from the site of injection in paravertebral ganglion 14.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
3.
Erichsen K Hausken T Ulvik RJ Svardal A Berstad A Berge RK 《Scandinavian journal of gastroenterology》2003,38(5):543-548
BACKGROUND: Iron deficiency anaemia is a frequent complication of Crohn disease. Treatment with ferrous iron (Fe2-) compounds is often unsatisfactory and is associated with gastrointestinal side effects. Theoretically, oral iron supplementation may even be harmful, because iron may reinforce intestinal inflammation by catalysing production of reactive oxygen species. We investigated the effect of ferrous iron on disease activity and plasma antioxidant status in patients with active Crohn disease. METHODS: Ten patients with Crohn disease and iron deficiency and 10 healthy controls were given ferrous fumarate 120 mg for 7 days. The Crohn Disease Activity Index, gastrointestinal complaints and blood samples for antioxidant status, anaemia, inflammation and iron absorption were investigated on day 1 and day 8. RESULTS: During 1 week of ferrous fumarate supplementation, the Crohn Disease Activity Index tended to increase (P = 0.071). Patients experienced aggravation of diarrhoea, abdominal pain and nausea. Plasma-reduced cysteine was lower (P = 0.038) in patients than it was in controls. One week of ferrous iron supplementation further decreased reduced cysteine (P < 0.001) and significantly decreased plasma-reduced glutathione (P = 0.004) in the patients. Serum iron increased significantly in patients after an oral iron load test (from 5.8 +/- 3.2 micromol/L to 30.9 +/- 13.1 micromol/L). CONCLUSIONS: Treatment of iron deficiency with ferrous fumarate deteriorated plasma antioxidant status and increased specific clinical symptoms in patients with active Crohn disease. Plasma reduced cysteine may be a sensitive indicator for oxidative stress in the intestine. 相似文献
4.
The increasing incidence and prevalence of eosinophilic oesophagitis outpaces changes in endoscopic and biopsy practice: national population‐based estimates from Denmark 下载免费PDF全文
5.
6.
Asma A. A. Zahidi Lee McIlreavy Jonathan T. Erichsen J. Margaret Woodhouse 《Investigative ophthalmology & visual science》2022,63(2)
PurposeChildren with Down''s syndrome (DS) are known to have poorer visual acuity than neurotypical children. One report has shown that children with DS and nystagmus also have poor acuity when compared to typical children with nystagmus. What has not been established is the extent of any acuity deficit due to nystagmus and whether nystagmus affects refractive error within a population with DS.MethodsClinical records from the Cardiff University Down''s Syndrome Vision Research Unit were examined retrospectively. Binocular visual acuity and refraction data were available for 50 children who had DS and nystagmus and 176 children who had DS but no nystagmus. Data were compared between the two groups and with published data for neurotypical children with nystagmus.ResultsThe study confirms the deficit in acuity in DS, compared to neurotypical children, of approximately 0.2 logMAR and shows a deficit attributable to nystagmus of a further 0.2 logMAR beyond the first year of life. Children with both DS and nystagmus clearly have a significant additional impairment. Children with DS have a wide range of refractive errors, but nystagmus increases the likelihood of myopia. Prevalence and axis direction of astigmatism, on the other hand, appear unaffected by nystagmus.ConclusionsNystagmus confers an additional visual impairment on children with DS and must be recognized as such by families and educators. Children with both DS and nystagmus clearly need targeted support. 相似文献
7.
8.
Bergithe E. Oftedal Mihaela Cuida Marthinussen Martina M. Erichsen Maria K. Tveitarås Anja Kjellesvik-Kristiansen Daniel Hammenfors 《Autoimmunity》2017,50(4):211-222
Autoimmune polyendocrine syndrome type I (APS-I) is a severe disease caused by mutations in the autoimmune regulator (AIRE) gene. We hypothesized that salivary gland dysfunction could be a possible unexplored component of these patients and here aimed to investigate salivary and lachrymal symptoms in the Norwegian cohort of APS-I patients (N?=?41) and the aetiology behind it. Sicca symptoms and possible corresponding underlying factors were assessed by subjective reports combined with objective measures of saliva and tear flow, serological testing, immune fluorescence microscopy, ultrasonography and searching for putative autoantibodies in the salivary glands. In addition, defensin and anti-defensin levels were analysed in patients and compared with healthy controls. Our results indicate mild salivary and/or lachrymal gland dysfunction manifesting in low saliva or tear flow in a total of 62% of APS-I patients. Serum IgG from 9 of 12 patients bound to targets in salivary gland biopsy slides, although the specificity and pattern of binding varied. There was no reactivity against known Sjögren-associated autoantigens in sera from APS-I patients using quantitative methods, but 11% were ANA positive by immunofluorescence microscopy. We identified several putative autoantigens in one patient, although none of these were verified as APS-I specific. We conclude that impaired salivary gland activity is part of the clinical picture of APS-I and our findings could indicate an autoimmune aetiology. We further show that APS-I patients have an altered antimicrobial signature in both sera and saliva, which requires further investigations. 相似文献
9.
N L Carlsen H Schroeder P V Bro G Erichsen B Hamborg-Pedersen K B Jensen O H Nielsen 《Medical and pediatric oncology》1985,13(4):180-186
One hundred and eighty cases of neuroblastomas from the four child oncology clinics are reviewed. The overall cure rate was 24%. During the 38-year period, there was a significant increase in survival from 0% during the period of 1943-1950 to 32% during the period of 1971-1980. This improved survival rate is most likely a result of adjuvant chemotherapy. Forty percent of the patients appear chronically ill, which reflects the fact that nearly 60% have metastases when they are first seen. In localized disease (stages I-II), the prognosis was favourable (cure rate 69%), while the prognosis for disseminated disease (stage III-IV) was poor (cure rate 5%). A favourable outcome was seen in patients under 1 year (survival rate 46%), and in patients with primary tumours located in the neck or mediastinum (survival rate 48%). When related to stage, however, the survival rates for the former tumours were not significantly better in patients below 1 year or in patients with cervical or thoracic tumours. As is the case in other studies, we found that survival is significantly poorer in males. 相似文献
10.
The distribution of preganglionic motoneurons supplying the ciliary ganglion in the cat was defined both qualitatively and quantitatively. These cells were retrogradely labeled directly, following injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the ciliary ganglion, or were transsynaptically labeled following injections of WGA into the vitreous chamber. Almost half of the cells are distributed rostral to the oculomotor nucleus, both in and lateral to the anteromedian nucleus. Of the remaining preganglionic motoneurons, roughly 20% of the total are located dorsal to the oculomotor nucleus. Strikingly few of these neurons are actually found within the Edinger-Westphal nucleus proper. Instead, the majority are found in the adjacent supraoculomotor area or along the midline between the two somatic nuclei. An additional population, roughly 30% of the total, is located ventral to the oculomotor nucleus. This study also provides evidence for a functional subdivision of this preganglionic population. Pupil-related preganglionic motoneurons were transsynaptically labeled by injecting WGA into the anterior chamber, while lens-related preganglionic motoneurons were transsynaptically labeled by injecting WGA into the ciliary muscle. The results suggest that the pupil-related preganglionic motoneurons, that is, those controlling the iris sphincter pupillae muscle, are located rostrally, in and lateral to the anteromedian nucleus. In contrast, lens-related preganglionic motoneurons, that is, those controlling the ciliary muscle are particularly prevalent caudally, both dorsal and ventral to the oculomotor nucleus. Thus, the cat intraocular muscle preganglionic innervation is spatially organized with respect to function, despite the dispersed nature of its distribution. 相似文献