全文获取类型
收费全文 | 241803篇 |
免费 | 20867篇 |
国内免费 | 14342篇 |
专业分类
耳鼻咽喉 | 2212篇 |
儿科学 | 3062篇 |
妇产科学 | 4881篇 |
基础医学 | 28291篇 |
口腔科学 | 4212篇 |
临床医学 | 30861篇 |
内科学 | 39825篇 |
皮肤病学 | 2815篇 |
神经病学 | 13545篇 |
特种医学 | 8561篇 |
外国民族医学 | 96篇 |
外科学 | 26654篇 |
综合类 | 34130篇 |
现状与发展 | 48篇 |
一般理论 | 45篇 |
预防医学 | 15102篇 |
眼科学 | 6673篇 |
药学 | 24191篇 |
164篇 | |
中国医学 | 10918篇 |
肿瘤学 | 20726篇 |
出版年
2024年 | 698篇 |
2023年 | 3486篇 |
2022年 | 8672篇 |
2021年 | 11392篇 |
2020年 | 8393篇 |
2019年 | 7556篇 |
2018年 | 8003篇 |
2017年 | 6978篇 |
2016年 | 6669篇 |
2015年 | 10102篇 |
2014年 | 12707篇 |
2013年 | 11896篇 |
2012年 | 17536篇 |
2011年 | 19224篇 |
2010年 | 11725篇 |
2009年 | 9387篇 |
2008年 | 12761篇 |
2007年 | 12806篇 |
2006年 | 12366篇 |
2005年 | 12445篇 |
2004年 | 8607篇 |
2003年 | 7640篇 |
2002年 | 6615篇 |
2001年 | 5998篇 |
2000年 | 6122篇 |
1999年 | 6419篇 |
1998年 | 3657篇 |
1997年 | 3680篇 |
1996年 | 2794篇 |
1995年 | 2590篇 |
1994年 | 2240篇 |
1993年 | 1501篇 |
1992年 | 2292篇 |
1991年 | 2000篇 |
1990年 | 1665篇 |
1989年 | 1455篇 |
1988年 | 1264篇 |
1987年 | 1178篇 |
1986年 | 942篇 |
1985年 | 748篇 |
1984年 | 493篇 |
1983年 | 381篇 |
1982年 | 225篇 |
1981年 | 201篇 |
1980年 | 191篇 |
1979年 | 243篇 |
1978年 | 141篇 |
1977年 | 112篇 |
1976年 | 97篇 |
1974年 | 116篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
鼻内镜治疗颅底疾病112例报告 总被引:1,自引:1,他引:0
目的探讨鼻内镜径路治疗颅底疾病的价值。方法2002年5月~2006年12月,对112例颅底疾病行鼻内镜径路手术,其中脑脊液鼻漏39例,垂体瘤4例,脑膜膨出或脑膜脑膨出3例,蝶筛囊肿9例,蝶窦炎伴息肉2例,真菌性蝶窦炎12例,内翻性乳头状瘤11例,鼻咽纤维血管瘤6例,骨化纤维瘤2例,骨纤维异常增殖2例,脊索瘤7例,颅咽管瘤2例,鳞癌10例,未分化癌1例,乳头状瘤癌变2例。结果全组均在鼻内镜下处理,其中20例病变为次全切除,包括鳞癌8例、未分化癌1例、脊索瘤7例、颅咽管瘤2例、骨纤维异常增殖2例。脑脊液鼻漏1次手术成功31例(79.5%),2次成功4例,3次成功4例,最终成功率100%。1例脑膜脑膨出术后2个月复发并伴脑脊液漏,内镜下再次手术成功。1例内翻性乳头状瘤术后11个月复发,改行鼻侧切开术。1例真菌性蝶窦炎术后4个月复发行再次内镜手术。1例脑脊液鼻漏术后颅内感染。结论鼻内镜径路可以处理多种颅底疾病,是一种安全、有效、微创的手术方式,但仍需严格掌握手术适应证,特别是恶性肿瘤。 相似文献
992.
Yao-Jong Yang Shih-Min Wang Chun-Ta Chen Mei-Chih Huang Chih-Jen Chang Ching-Chuan Liu 《台湾医志》2003,102(6):375-378
BACKGROUND AND PURPOSE: Helicobacter pylori infection is primarily acquired in early childhood and its transmission routes are debated. The aims of this study were to determine the seroprevalence of anti-H. pylori immunoglobulin G (IgG) in Taiwanese and to investigate whether a common mode of transmission could be shared between H. pylori and hepatitis A virus (HAV). METHODS: An enzyme-linked immunosorbent assay (ELISA) was used to investigate the prevalence of H. pylori among 924 healthy volunteers aged less than 40 years, and radioimmunoassay for HAV infection was conducted in 500 subjects from the same population. The kappa statistic was used to measure the difference in positivity for the 2 infections in a subgroup of 500 subjects who had their sera simultaneously tested for anti-H. pylori and anti-HAV antibodies. RESULTS: The seroprevalence of anti-H. pylori IgG was 16.7% in subjects aged < 16 years and 38.3% at ages >or= 16 years. Most children (99%) under the age of 16 were seronegative for HAV. The prevalence of H. pylori infection increased rapidly with age, at 1%/year and 0.8%/year for children and adults, respectively. The rate of H. pylori infection was higher in male (21%) than in female (12%) children (p < 0.01; OR, 2.0; 95% confidence interval, 1.2 to 3.0). No significant difference in seroprevalence between genders was noted in subjects aged >or= 16 years. The agreement in the trend of seropositivity between both infections in the age groups 1 to 10 years and 10 to 20 years was worse than chance (kappa = -0.56) and little better than chance (kappa = 0.01), respectively. CONCLUSIONS: Acquisition of H. pylori infection occurs at a young age, and male children are more likely to develop the infection. The main transmission route of HAV, the fecal-oral route, did not seem to be responsible for H. pylori transmission in this Taiwanese cohort. 相似文献
993.
994.
Jie-Yuan Li Alberto J Espay Carolyn A Gunraj Pramod K Pal Danny I Cunic Anthony E Lang Robert Chen 《Movement disorders》2007,22(6):813-821
Mirror movements (MM) occur in early, asymmetric Parkinson's disease (PD). To examine the pathophysiology of MM in PD, we studied 13 PD patients with MM (PD-MM), 7 PD patients without MM (PD-NM), and 14 normal subjects. Cross-correlogram did not detect common synaptic input to motoneuron pools innervating homologous hand muscles in PD-MM patients. Transcranial magnetic stimulation studies showed no significant difference in ipsilateral motor-evoked potentials between PD-MM patients and normal subjects. The MM side of PD-MM patients showed a slower increase in ipsilateral silent period area with higher level of muscle contraction than the non-MM side and normal subjects. There was less interhemispheric inhibition (IHI) at long interstimulus intervals of 20 to 50 ms in PD-MM than PD-NM. IHI reduced short interval intracortical inhibition in normal subjects and PD-NM, but not in PD-MM. IHI significantly increased intracortical facilitation in PD-MM and PD-NM patients, but not in normal subjects. Our results suggest that MM in PD is due to activation of the contralateral motor cortex. PD-MM patients had reduced transcallosal inhibitory effects on cortical output neurons and on intracortical inhibitory circuits compared to PD-NM patients and controls. These deficits in transcallosal inhibition may contribute to MM in PD patients. 相似文献
995.
Jong-Kai Hsiao Ming-Fong Tai Hung-Hao Chu Shin-Tai Chen Hung Li Dar-Ming Lai Sung-Tsang Hsieh Jaw-Lin Wang Hon-Man Liu 《Magnetic resonance in medicine》2007,58(4):717-724
The purpose of this work was to evaluate the efficacy of labeling human mesenchymal stem cells (hMSCs) by ionic superparamagnetic iron oxide (SPIO) without a transfection agent and verifying its capability to be detected with clinical 1.5 T magnetic resonance (MR) at the single-cell level. Human hMSCs were incubated for 24 h with an ionic SPIO, Ferucarbotran. The labeling efficiency of hMSCs was determined by iron content measurement spectrophotometrically, and the influence of labeling on cell behavior was ascertained by examination of cell viability using the trypan blue exclusion method, cell proliferation analysis using MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, mitochondrial membrane potential (MMP) change, differentiation capacity, and reactive oxygen species (ROS) production measured by dichlorofluorescein diacetate (DCFDA) fluorescent probe. Labeled hMSCs were scanned under 1.5 T MRI with three-dimensional (3D) and two-dimensional (2D) T(2)-weighted gradient echo (GRE) pulse sequences. Human hMSC labeling without transfection agent was efficient. The iron content in hMSCs was 23.4 pg Fe/cell. No significant change was found in viability, proliferation, MMP change, ROS production, or differentiation capacity. About 45.2% of the hMSCs could be detected using 1.5 T MRI at the single cell level with 3D GRE and four repetitions. 相似文献
996.
The disaccharide trehalose is a key element involved in anhydrobiosis (the capability of surviving almost complete dehydration) in many organisms. Its presence also confers resistance to desiccation and high osmolarity in bacterial and human cells by protecting proteins and membranes from denaturation. The present study used a novel murine dry eye model induced by controlled low-humidity air velocity to determine whether topically applied trehalose could heal ocular surface epithelial disorders caused by ocular surface desiccation. In addition, the efficacy of 87.6 mM trehalose eyedrops was compared with that of 20% serum, the efficacy of which has been well documented. Mice ocular surface epithelial disorders were induced by exposure of murine eyes to continuous controlled low-humidity air velocity in an intelligently controlled environmental system (ICES) for 21 days, which accelerated the tear evaporation. The mice were then randomized into three groups: the control group received PBS (0.01M) treatment; a second group received 87.6 mM trehalose eyedrops treatment; and the third group received mice serum eyedrops treatment. Each treatment was administered as a 10 μl dose every 6 h for 14 days. The resultant changes in corneal barrier function and histopathologic examination of cornea and conjunctiva were analyzed and the level of apoptosis on the ocular surface was assessed using active caspase-3. After 14 days of treatment, the corneal fluorescein staining area, the ruffling and desquamating cells on the apical corneal epithelium, as well as the apoptotic cells on ocular surface epithelium had significantly reduced in eyes treated with trehalose compared with those treated with serum and PBS. In contrast, after 14 days of treatment, improvements in the thickness of the corneal epithelium, the squamous metaplasia in conjunctival epithelium and the number of goblet cells of the conjunctiva were less marked in eyes treated with trehalose compared with serum. These results demonstrated that trehalose could improve the appearance of ocular surface epithelial disorders due to desiccation through suppression of apoptosis. Trehalose produces some of the same responses as serum upon topical application and can maintain corneal health. 相似文献
997.
Adeno-Associated Viral Vector-Mediated Interleukin-10 Prolongs Allograft Survival in a Rat Kidney Transplantation Model 总被引:5,自引:0,他引:5
B. Chen M. H. Kapturczak R. Joseph J. F. George M. Campbell-Thompson C. H. Wasserfall M. A. Atkinson C. C. Tisher T. R. Flotte A. Agarwal S. Chen 《American journal of transplantation》2007,7(5):1112-1120
Interleukin-10 (IL-10) is a pleiotropic cytokine that plays a pivotal role in the regulation of immune responses. Hence, we evaluated the effects of a recombinant adeno-associated viral vector 1 (rAAV1) encoding rat IL-10 (rAAV1-IL-10) in a rat model of kidney allograft rejection. Dark Agouti rat kidneys were transplanted into Wistar-Furth (WF) rats 8 weeks following a single intramuscular administration of either rAAV1-IL-10 or rAAV1-green fluorescence protein (GFP). Isografts (WF-WF) served as an additional experimental control. Both allograft and isograft recipients received daily cyclosporine (10 mg/kg) for 14 days after transplantation. Serum IL-10 levels increased at 8, 12 and 16 weeks following vector administration in rAAV1-IL-10-treated animals, but not in rAAV1-GFP and isograft groups. rAAV1-IL-10 treatment resulted in lower BUN and creatinine levels (p<0.001), as well as increased allograft survival rates from 22% to 90%. Allograft histological abnormalities were significantly attenuated in the rAAV1-IL-10-treated rats compared with those of rAAV1-GFP controls. Serum levels of proinflammatory cytokines such as growth-related oncogene were also significantly higher in the rAAV1-GFP group than in the rAAV1-IL-10 group. These data suggest delivery of IL-10 using a rAAV1 vector improves renal function and prolongs graft survival in a rat model of kidney transplant rejection. 相似文献
998.
Thorium is considered as a chemical analog of other tetravalent actinides. Herein, the sorption of Th(IV) on TiO(2) in the presence or absence of soil fulvic acid (FA)/humic acid (HA) as a function of pH, ionic strength and FA/HA concentration has been studied by a batch method. The morphology was characterized by scanning electron microscopy (SEM). The results indicate that sorption of Th(IV) on TiO(2) increases from 0% to approximately 94% at pH 1 approximately 4, and then maintains level with increasing pH values. Both FA and HA have a positive effect on Th(IV) sorption at low pH values and the contribution of FA on Th(IV) sorption is rather higher than that of HA at pH<4. The sorption is weakly dependent on the concentration of KNO(3) in solution, but the cations K(+), Na(+) and Li(+) influence Th(IV) sorption more obviously. The batch results indicate that the inner sphere complex formation is formed at bare surfaces or FA/HA-bound TiO(2) particle surfaces. Results of SEM analysis show that the particle sizes of TiO(2), Th-TiO(2) and Th-HA-TiO(2) colloids are quite different. Surface complexation may be considered as the main sorption mechanism. 相似文献
999.
Shaoyi Chen Coleen M Atkins Chunli L Liu Ofelia F Alonso W Dalton Dietrich Bingren R Hu 《Journal of cerebral blood flow and metabolism》2007,27(5):939-949
In response to traumatic brain injury (TBI), neurons initiate neuroplastic processes through the activation of intracellular signaling pathways. However, the molecular mechanisms underlying neuroplasticity after TBI are poorly understood. To study this, we utilized the fluid-percussion brain injury (FPI) model to investigate alterations in the mammalian target of rapamycin (mTOR) signaling pathways in response to TBI. Mammalian target of rapamycin stimulates mRNA translation through phosphorylation of eukaryotic initiation factor 4E binding protein-1 (4E-BP1), p70 ribosomal S6 kinase (p70S6K), and ribosomal protein S6 (rpS6). These pathways coordinate cell growth and neuroplasticity via dendritic protein synthesis. Rats received sham surgery or moderate parasagittal FPI on the right side of the parietal cortex, followed by 15 mins, 30 mins, 4 h, 24 h, or 72 h of recovery. Using Western blot analysis, we found that mTOR, p70S6K, rpS6, and 4E-BP1 phosphorylation levels were significantly increased in the ipsilateral parietal cortex and hippocampus from 30 mins to 24 h after TBI, whereas total protein levels were unchanged. Using confocal microscopy to localize these changes, we found that rpS6 phosphorylation was increased in the parietal cortex and all subregions of the hippocampus. In accordance with these results, eIF4E, a key, rate-limiting mRNA translation factor, was also phosphorylated by mitogen-activated protein kinase-interacting kinase 1 (Mnk1) 15 mins after TBI. Together, these results suggest that changes in mRNA translation may be one mechanism that neurons use to respond to trauma and may contribute to the neuroplastic changes observed after TBI. 相似文献
1000.
X线引导下经皮通用脊柱系统内固定治疗胸腰椎骨折 总被引:4,自引:1,他引:3
目的探讨X线引导下经皮通用脊柱系统(USS)内固定治疗胸腰椎骨折的可行性.方法 2002年10月~2004年5月对无须减压胸腰椎骨折8例采用后路经皮USS椎弓根螺钉植入,在椎旁肌深层置入固定棒行伤椎复位固定.结果手术时间120~240 min,平均140 min.术中出血量20~90 ml,平均40 ml.后凸Cobb's角术前(21.5±4.3)°、术后(2.7±1.5)°(t=17.541,P=0.001),椎体塌陷术前18.5%±4.1%、术后2.4%±1.0%(t=16.504,P=0.001).术后3周佩戴腰围支具下床,复查Frankel分级,C级恢复至D级2例,D级恢复至E级1例,保持D级1例,保持E级4例.结论经皮USS内固定治疗无须减压的胸腰椎骨折创伤小,恢复快,但技术难度高,X线暴露时间长. 相似文献