全文获取类型
收费全文 | 3965篇 |
免费 | 258篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 190篇 |
妇产科学 | 65篇 |
基础医学 | 510篇 |
口腔科学 | 63篇 |
临床医学 | 351篇 |
内科学 | 926篇 |
皮肤病学 | 65篇 |
神经病学 | 252篇 |
特种医学 | 324篇 |
外科学 | 407篇 |
综合类 | 68篇 |
预防医学 | 369篇 |
眼科学 | 66篇 |
药学 | 214篇 |
中国医学 | 11篇 |
肿瘤学 | 315篇 |
出版年
2022年 | 17篇 |
2021年 | 52篇 |
2020年 | 48篇 |
2019年 | 60篇 |
2018年 | 75篇 |
2017年 | 59篇 |
2016年 | 62篇 |
2015年 | 99篇 |
2014年 | 130篇 |
2013年 | 183篇 |
2012年 | 215篇 |
2011年 | 221篇 |
2010年 | 135篇 |
2009年 | 163篇 |
2008年 | 212篇 |
2007年 | 197篇 |
2006年 | 193篇 |
2005年 | 163篇 |
2004年 | 129篇 |
2003年 | 124篇 |
2002年 | 136篇 |
2001年 | 115篇 |
2000年 | 109篇 |
1999年 | 97篇 |
1998年 | 110篇 |
1997年 | 86篇 |
1996年 | 85篇 |
1995年 | 68篇 |
1994年 | 71篇 |
1993年 | 62篇 |
1992年 | 50篇 |
1991年 | 61篇 |
1990年 | 67篇 |
1989年 | 82篇 |
1988年 | 65篇 |
1987年 | 51篇 |
1986年 | 47篇 |
1985年 | 30篇 |
1984年 | 43篇 |
1983年 | 35篇 |
1982年 | 21篇 |
1981年 | 27篇 |
1980年 | 20篇 |
1979年 | 25篇 |
1978年 | 21篇 |
1977年 | 23篇 |
1976年 | 10篇 |
1975年 | 11篇 |
1974年 | 15篇 |
1973年 | 10篇 |
排序方式: 共有4233条查询结果,搜索用时 15 毫秒
21.
CA von Arnim R Spoelgen ID Peltan M Deng S Courchesne M Koker T Matsui H Kowa SF Lichtenthaler MC Irizarry BT Hyman 《The Journal of neuroscience》2006,26(39):9913-9922
The beta-amyloid (Abeta) precursor protein (APP) is cleaved sequentially by beta-site of APP-cleaving enzyme (BACE) and gamma-secretase to release the Abeta peptides that accumulate in plaques in Alzheimer's disease (AD). GGA1, a member of the Golgi-localized gamma-ear-containing ARF-binding (GGA) protein family, interacts with BACE and influences its subcellular distribution. We now report that overexpression of GGA1 in cells increased the APP C-terminal fragment resulting from beta-cleavage but surprisingly reduced Abeta. GGA1 confined APP to the Golgi, in which fluorescence resonance energy transfer analyses suggest that the proteins come into close proximity. GGA1 blunted only APP but not notch intracellular domain release. These results suggest that GGA1 prevented APP beta-cleavage products from becoming substrates for gamma-secretase. Direct binding of GGA1 to BACE was not required for these effects, but the integrity of the GAT (GGA1 and TOM) domain of GGA1 was. GGA1 may act as a specific spatial switch influencing APP trafficking and processing, so that APP-GGA1 interactions may have pathophysiological relevance in AD. 相似文献
22.
Both H2O2 (IC50 = 70 microM) and HOCl (IC50 = 8.5 microM) inhibited mitogen-induced MNL proliferation in a dose-dependent manner. This was found to be due to a depletion of intracellular ATP by at least two distinct mechanisms. HOCl and high concentrations (greater than 100 microM) of H2O2 inhibit ATP generation via sulfhydryl group oxidation on the active site of the glyceraldehyde-3-phosphate dehydrogenase (G3PDH) enzyme of the glycolytic pathway. On the other hand, low H2O2 concentrations cause ATP depletion by an activation of the DNA repair enzyme, poly(ADP-ribose)polymerase (pADPRP), leading to consumption of NAD+, an essential cofactor for G3PDH. The anti-oxidants ascorbate and cysteine protected MNL against the anti-proliferative effects of HOCl. Similar results were achieved with the HOCl-mediated inhibition of ATP production and G3PDH activity. However, ascorbate was unable to protect against H2O2-mediated inhibition of MNL functions, while cysteine protected against the inhibitory effects on ATP production and G3PDH activity, induced by this oxidant. 相似文献
23.
CA Schroeter† L Kaas† JJ Waterval† PM Bos‡ HAM Neumann§ 《Journal of the European Academy of Dermatology and Venereology》2007,21(9):1170-1174
AIM: The aim of this pilot study was an investigation on photodynamic therapy (PDT) whether it is a good alternative for treating periungual and subungual warts of the hands. STUDY DESIGN: Twenty patients (mean age: 30.5 years) with a total of 40 periungual and subungual warts were treated with PDT. A photosensitizer, 20%delta-aminolevulinic acid was applied on the warts. After a mean incubation time of 4.6 h (SD: 1.2), the warts were irradiated with the VersaLight for 5-30 min (15.2 +/- 4.3 min). RESULTS: After a mean of 4.5 treatments a mean clearance of 100% was achieved in 90% of the patients. One patient (5%) showed a clearance of 50% and another showed no improvement. The subungual or periungual location of the wart had no influence on the number of treatments or end result (P > 0.05). There were two recurrences during the mean follow-up period of 5.9 months (SD: 7.6). Besides mainly pain and hyperpigmentation, most treatments had no side-effects. CONCLUSION: PDT can offer a good alternative for treating periungual warts of the hands. Larger studies are indicated. 相似文献
24.
Characteristics of wheeze during histamine-induced airways obstruction in children with asthma.
下载免费PDF全文
![点击此处可从《Thorax》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S. Rietveld E. H. Dooijes L. H. Rijssenbeek-Nouwens F. Smit P. J. Prins A. M. Kolk W. A. Everaerd 《Thorax》1995,50(2):143-148
BACKGROUND--An automated system has been developed for the detection of sound patterns suggestive of airways obstruction in long term recordings. The first step, presented here, was tracheal sound recording during histamine-induced airways obstruction. METHODS--The tracheal sounds of 29 children aged 8-19 years with asthma were recorded during airways obstruction caused by histamine inhalation using a system for continuous respiratory telemetry and computer analysis. Sound patterns were analysed, classified, and related to airways obstruction measured by lung function tests based on the forced expiratory volume in one second (FEV1). RESULTS--Five sound patterns were identified, one dominant sensitive and four specific to a fall in FEV1 of > 20%. The presence of at least one of three specific sound patterns during unforced respiration predicted a fall in FEV1 of > 20% in 87.5% of the subjects. The inspiratory and expiratory sound patterns were almost equally informative of airways obstruction. CONCLUSIONS--Wheezes can be differentiated with more precision than is currently accepted. Tracheal sound patterns are sensitive and specific predictors of histamine-induced airways obstruction. These patterns are neither invariably nor proportionally related to the results of lung function testing. However, they can be used for detection of airways obstruction on the basis of their presence or absence. 相似文献
25.
One-day-old broiler chicks were infected orally with spirochaetes isolated from cases of intestinal disorder in humans. Three different isolates were studied in an experiment of 22 days duration. No signs of clinical disease were observed; the infection did not cause changes in the concentration of carotenoids or in the activity of alkaline phosphatase in the serum. Spirochaetes were shed in the caecal faeces. At autopsy, no lesions were seen in the intestinal tracts of the birds. Large numbers of spirochaetes were present in the caecum of 30 to 100% of the infected birds; in a few birds small numbers of spirochaetes were observed in scrapings from the mucosa of the small intestine. On histological examination massive colonisation of the caecal mucosa was observed. Spirochaetes of two isolates had invaded the caecal mucosa and for one of these, they were found between enterocytes, but not below the basement membrane. The other isolate had produced gap-like lesions, subepithelial accumulations of spirochaetes and focal erosion. No signs of an inflammatory reaction were observed. 相似文献
26.
Leukoencephalopathy with swelling in children and adolescents: MRI patterns and differential diagnosis 总被引:7,自引:0,他引:7
M. S. van der Knaap J. Valk P. G. Barth L. M. E. Smit B. G. M. van Engelen P. Tortori Donati 《Neuroradiology》1995,37(8):679-686
In children, several neurological disorders are characterised by spongiform leukoencephalopathy. MRI of the brain typically shows white matter swelling, but does not enable differentiation of the various underlying disorders. The aim of this article is optimisation of the diagnostic value of MRI in leukoencephalopathy accompanied by swelling. MRI-based inclusion criteria were met by 20 patients in our database. The images were analysed using a detailed scoring list. In 13 of the 20 patients the clinical diagnosis was known (11 definite and 2 probable diagnoses). Characteristic MRI abnormalities could be defined in these patients. Of the 7 patients without a diagnosis, 5 had identical MRI abnormalities: difuse hemisphere swelling and typical cysts in frontoparietal subcortical white matter and the tips of the temporal lobes. The clinical picture was also similar in these patients, suggesting a similar disease. 相似文献
27.
Xander Smit Johan W van Neck Menno J Ebeli Steven E R Hovius 《Nordisk plastikkirurgisk forening [and] Nordisk klubb for handkirurgi》2004,38(6):321-325
Walking track analysis is a widely accepted technique for functional evaluation after sciatic nerve repair in rats, but it is labour-intensive. In 2000, Bervar described a time-saving digitised static footprint analysis. In that study there were good correlations between the traditional sciatic function index (SFI) and the newly-developed static sciatic index (SSI) and static toe spread factor (TSF), respectively. Despite promising results, static footprint analysis is still not widely used. The present study was designed to validate it. After transection of the sciatic nerve, end-to-end repair was assessed using video recorded dynamic and static footprints in 45 Wistar rats. We found an even better correlation between the SFI and both the SSI and the static TSF. In conclusion, static footprint analysis is a time-saving and easy technique for accurate functional assessment of peripheral nerve regeneration in rats. 相似文献
28.
29.