全文获取类型
收费全文 | 70286篇 |
免费 | 6399篇 |
国内免费 | 5105篇 |
专业分类
耳鼻咽喉 | 422篇 |
儿科学 | 728篇 |
妇产科学 | 890篇 |
基础医学 | 8776篇 |
口腔科学 | 1225篇 |
临床医学 | 9386篇 |
内科学 | 10670篇 |
皮肤病学 | 777篇 |
神经病学 | 3685篇 |
特种医学 | 2424篇 |
外国民族医学 | 42篇 |
外科学 | 7152篇 |
综合类 | 12202篇 |
现状与发展 | 17篇 |
一般理论 | 2篇 |
预防医学 | 4382篇 |
眼科学 | 1837篇 |
药学 | 7444篇 |
75篇 | |
中国医学 | 3835篇 |
肿瘤学 | 5819篇 |
出版年
2024年 | 350篇 |
2023年 | 1238篇 |
2022年 | 2882篇 |
2021年 | 3641篇 |
2020年 | 2696篇 |
2019年 | 2422篇 |
2018年 | 2410篇 |
2017年 | 2083篇 |
2016年 | 2083篇 |
2015年 | 3171篇 |
2014年 | 3992篇 |
2013年 | 3312篇 |
2012年 | 4834篇 |
2011年 | 5718篇 |
2010年 | 3301篇 |
2009年 | 2507篇 |
2008年 | 3461篇 |
2007年 | 3562篇 |
2006年 | 3642篇 |
2005年 | 3500篇 |
2004年 | 2259篇 |
2003年 | 2224篇 |
2002年 | 1870篇 |
2001年 | 1708篇 |
2000年 | 1785篇 |
1999年 | 1983篇 |
1998年 | 1275篇 |
1997年 | 1361篇 |
1996年 | 1014篇 |
1995年 | 898篇 |
1994年 | 782篇 |
1993年 | 490篇 |
1992年 | 606篇 |
1991年 | 520篇 |
1990年 | 447篇 |
1989年 | 393篇 |
1988年 | 329篇 |
1987年 | 284篇 |
1986年 | 251篇 |
1985年 | 173篇 |
1984年 | 103篇 |
1983年 | 71篇 |
1982年 | 38篇 |
1981年 | 52篇 |
1980年 | 28篇 |
1979年 | 38篇 |
1964年 | 1篇 |
1963年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
We report clinical, neuroradiologic features, and neuropathologic findings of a 76‐year‐old man with coexistent Pick’s disease and progressive supranuclear palsy. The patient presented with loss of recent memory, abnormal behavior and change in personality at the age of 60. The symptoms were progressive. Three years later, repetitive or compulsive behavior became prominent. About 9 years after onset, he had difficulty moving and became bed‐ridden because of a fracture of his left leg. His condition gradually deteriorated and he developed mutism and became vegetative. The patient died from pneumonia 16 years after the onset of symptoms. Serial MRI scans showed progressive cortex atrophy, especially in the bilateral frontal and temporal lobes. Macroscopic inspection showed severe atrophy of the whole brain, including cerebrum, brainstem and cerebellum. Microscopic observations showed extensive superficial spongiosis and severe neuronal loss with gliosis in the second and third cortical layers in the frontal, temporal and parietal cortex. There were Pick cells and argyrophilic Pick bodies, which were tau‐ and ubiquitin‐positive in neurons of layers II–III of the above‐mentioned cortex. Numerous argyrophilic Pick bodies were observed in the hippocampus, especially in the dentate fascia. In addition, moderate to severe loss of neurons was found with gliosis and a lot of Gallyas/tau‐positive globus neurofibrillary tangles in the caudate nucleus, globus pallidus, thalamus, substantia nigra, locus coeruleus and dentate nucleus. Numerous thorned‐astrocytes and coiled bodies but no‐tuft shaped astrocytes were noted in the basal ganglion, brainstem and cerebellar white matter. In conclusion, these histopathological features were compatible with classical Pick’s disease and coexistence with progressive supranuclear palsy without tuft‐shaped astrocytes. 相似文献
3.
OBJECTIVE: To understand the role of nasal mucous epithelial cells to hypoxia in early stage of nasal polyps(NP) formation. METHODS: Epithelial cells of NP and inferior turbinate (IT) were cultured without serum under normal oxygen and hypoxia, and stimulus of inflammatory cytokines. Erythropoietin (EPO) was regarded as hypoxia mark, and expression of vascular endothelial growth factor(VEGF) mRNA and protein derived from epithelial cells were detected respectively by in situ hybridization and ELISA. RESULTS: 1. Under hypoxia, EPO mRNA was expressed intensely in epithelial cells from NP and IT, and there was no significant difference between both of them. This result suggested that EPO might be regarded as a hypoxic mark. 2. The ability of producing VEGF mRNA increased with cytokines stimulation, especially under hypoxia. Protein level of VEGF from epithelial cells of NP and IT increased with cytokines stimulation, especially in hypoxia and was time-dependent. CONCLUSION: Epithelial cells actively produce vast VEGF under hypoxia. The VEGF induced by hypoxia of the mucosa in middle meatus is of importance in the formation of nasal polyps(NP) in early stage, which may be the major cause of NP formation in middle meatus. 相似文献
4.
X Dong M He X Song B Lu Y Yang S Zhang N Zhao L Zhou Y Li X Zhu R Hu 《Diabetic medicine》2007,24(12):1482-1486
AIMS: Our aim was to assess performances of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease (MDRD) formulae in estimating glomerular filtration rate (GFR) in Chinese diabetic populations and their association with vascular risks. METHODS: A total of 1009 patients with Type 2 diabetes were categorized into low estimated GFR groups (GFR < 60 ml/min/1.73 m(2)) and control groups by the two equations. The performances of these formulae were assessed at different stages of kidney function. Carotid artery intima-media thickness (IMT) and the prevalence of diabetic retinopathy or albuminuria were compared among the groups. The ability of these formulae to identify established vascular risk markers using sensitivity, specificity, positive and negative predictive values were also compared. RESULTS: The prevalence of low estimated GFR was 32.7% with the Cockcroft-Gault formula and 5.2% with the MDRD formula, respectively. In low estimated GFR subjects by the MDRD formula, IMT was significantly thicker than those by the Cockcroft-Gault formula (1.2 mm vs. 1.0 mm; P < 0.05), with a higher prevalence of albuminuria (78.4 vs. 52.8%, P < 0.05) and diabetic retinopathy (46.5 vs. 30.5%; P < 0.05). The Cockcroft-Gault formula gave a specificity of 71.7% and a sensitivity of 37.0%, and the MDRD formula gave a specificity of 96.6% and a sensitivity of 7.9% in estimating low GFR relevant for established vascular risks. CONCLUSIONS: These formulae performed differently in Chinese diabetic populations. The simplified MDRD formula is minimally superior to the Cockcroft-Gault formula for its high specificity and positive predictive values in estimating low GFR relevant for vascular risks. 相似文献
5.
Gelin Xu Xinfeng Liu Wusheng Zhu Qin Yin Renliang Zhang Xiaobing Fan 《Blood coagulation & fibrinolysis》2007,18(2):193-197
This study evaluated the safety and efficacy of batroxobin in treating hyperfibrinogenemia for secondary stroke prevention. Patients with ischemic stroke or transient ischemic attack (TIA) were measured for plasma fibrinogen levels. Selected participants had concomitant hyperfibrinogenemia (plasma fibrinogen > or = 3.0 g/l). Patients enrolled between 1 July 2003 and 31 December 2004 were treated with batroxobin; patients enrolled between 1 January 2002 and 30 June 2003 were treated without batroxobin. Batroxobin was administered intermittently via intravenous injection at 3-monthly intervals. Patients in both groups were followed for 1 year. Any cerebrovascular events and suspected adverse events were recorded. In total, 112 ischemic stroke/TIA patients with concomitant hyperfibrinogenemia were enrolled, 52 being treated with batroxobin and 60 without batroxobin. Six patients (11.5%) with batroxobin and 16 patients (26.7%) without batroxobin had recurrent cerebral ischemic events during follow-up. Stroke/TIA recurrence in patients without batroxobin was higher than that in patients with batroxobin (P < 0.05). Two patients with batroxobin and two patients without batroxobin developed hemorrhagic stroke during follow-up. There were five deaths (9.6%) in the batroxobin group, and seven deaths (11.7%) in the nonbatroxobin group during follow-up (P > 0.05). Intermittent intravenous injection of batroxobin can efficiently reduce the risk for stroke/TIA recurrence in patients with concomitant hyperfibrinogenemia. 相似文献
6.
7.
8.
To study the pathological and histochemical characteristics of lesions in piglet livers infected with Taenia saginata asiatica (T. saginata asiatica) throughout the different stages, piglets were fed with eggs of T. saginata asiatica and raised in isolation in an animal center to establish the T. saginata asiatica infection model with normal piglets as control. The pathological changes in the piglet livers were observed after the infection
using liver sections stained with hematoxylin and eosin. Histochemical methods were used to check the changes in lipid, glycogen
and protein content in the liver. The data collected by image analysis were analyzed statistically with Statistical Package
for the Social Science. The results show that T. saginata asiatica-exposed piglets were indeed infected. Inflammatory reactions began on the fourth day and progressed rapidly. Kupffer cell
hyperplasia, hepatic hydropic degeneration and ballooning degeneration were found in the 10th–20th days after infection. Hepatic
central veins and hepatic sinusoids were dilated and congested. Spotty necrosis occurred in some local liver tissues. In the
40th–60th days, granulomatous reactions and mild hepatocirrhosis were the main lesions. In the 70th–80th days, hepatocirrhosis
and bile duct proliferation were observed in the liver. In the different stages, lipid drops were increased while glycogen
and protein levels were decreased to some degree. There was a significant difference in metabolism between the infected group
and the control group (P < 0.01). It is concluded that pigs are the favorable intermediate host of T. saginata asiatica and its infection can result in serious pathological and histochemical lesions in host organs.
Translated from Journal of Guiyang Medical College, 2006, 31(4): 296–300 [译自: 贵阳医学院学报] 相似文献
9.
10.
Effect of endotoxin and a burn injury on lung and liver lipid peroxidation and catalase activity 总被引:1,自引:0,他引:1
Both endotoxin and a burn alone produce oxidant-induced tissue lipid peroxidation. The endotoxin response is due in large part to hydrogen peroxide. The combination of endotoxin after a burn results in an increased liver, but not lung, oxidant injury. Our purpose was to determine whether the burn oxidant injury inactivated endogenous liver tissue catalase, thereby amplifying a subsequent H2O2 insult. Twenty-six adult sheep were studied. Twelve sheep had a 15% TBS burn. Tissue catalase activity, measured in lung and liver 3 days postburn, was significantly decreased from a control of 3.58 +/- 1.8 and 193 +/- 63, respectively, to 1.72 +/- 0.63 and 148 +/- 33 k(sec-1)/0.5 gram tissue. The addition of endotoxin 3 days postburn resulted in an increase in liver malondialdehyde, MDA, a measure of lipid peroxidation, from a control of 110 +/- 80 to 450 +/- 54 nmol/gram tissue. This value was significantly greater than the 210 +/- 80 nmol/gram tissue seen after endotoxin alone. Lung tissue MDA with burn and endotoxin was 65 +/- 8 compared to 42 +/- 7 for control and 80 +/- 6 nmol/gram for endotoxin alone. We conclude that a decrease in liver catalase activity occurs after a burn. The decrease corresponds to an accentuated oxidant-induced lipid peroxidation after an added endotoxin insult where H2O2 is known to be an etiologic agent. The catalase activity also decreases in postburn lung, but accentuated lung damage was not seen, indicating a variable tissue response from the burn-induced decrease in antioxidant activity.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献