全文获取类型
收费全文 | 56390篇 |
免费 | 5267篇 |
国内免费 | 4113篇 |
专业分类
耳鼻咽喉 | 349篇 |
儿科学 | 484篇 |
妇产科学 | 567篇 |
基础医学 | 6539篇 |
口腔科学 | 1026篇 |
临床医学 | 7807篇 |
内科学 | 8036篇 |
皮肤病学 | 493篇 |
神经病学 | 2827篇 |
特种医学 | 2041篇 |
外国民族医学 | 42篇 |
外科学 | 5330篇 |
综合类 | 10351篇 |
现状与发展 | 19篇 |
一般理论 | 1篇 |
预防医学 | 3740篇 |
眼科学 | 1775篇 |
药学 | 6136篇 |
39篇 | |
中国医学 | 3498篇 |
肿瘤学 | 4670篇 |
出版年
2024年 | 225篇 |
2023年 | 1030篇 |
2022年 | 2527篇 |
2021年 | 3256篇 |
2020年 | 2332篇 |
2019年 | 1886篇 |
2018年 | 2118篇 |
2017年 | 1791篇 |
2016年 | 1748篇 |
2015年 | 2730篇 |
2014年 | 3365篇 |
2013年 | 2770篇 |
2012年 | 4159篇 |
2011年 | 4667篇 |
2010年 | 2693篇 |
2009年 | 2238篇 |
2008年 | 2845篇 |
2007年 | 2854篇 |
2006年 | 2856篇 |
2005年 | 2850篇 |
2004年 | 1882篇 |
2003年 | 1748篇 |
2002年 | 1501篇 |
2001年 | 1200篇 |
2000年 | 1278篇 |
1999年 | 1334篇 |
1998年 | 896篇 |
1997年 | 839篇 |
1996年 | 652篇 |
1995年 | 613篇 |
1994年 | 515篇 |
1993年 | 313篇 |
1992年 | 393篇 |
1991年 | 311篇 |
1990年 | 289篇 |
1989年 | 241篇 |
1988年 | 225篇 |
1987年 | 172篇 |
1986年 | 143篇 |
1985年 | 105篇 |
1984年 | 46篇 |
1983年 | 42篇 |
1982年 | 18篇 |
1981年 | 20篇 |
1980年 | 15篇 |
1979年 | 15篇 |
1977年 | 2篇 |
1973年 | 2篇 |
1935年 | 4篇 |
1910年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Transitional mucosa adjacent to colorectal cancers is essentially characterized by an excess of sialomucins at the expense of the normally predominant sulphomucins in epithelial cells lining the intestinal crypts which presents the early stage of oncogenic transformation of colorectal epithelium. The presence or absence of sialomucins at the resection margins was studied histochemically using the high iron diamine-alcian blue(HID-AB) stain in 64 rectal cancer patients in Dukes' B stage who underwent curative anterior resection. The correlation was revealed between the presence of sialomucins at the resection margins and subsequent development of local tumour recurrence. Fourteen of 27 patients (51.9%) with sialomucins predominant pattern at either resection margin developed local recurrence compared with 4 of 37 patients (10.8%) with sulphomucins predominant pattern (P less than 0.001). It is suggested that determination of the transitional mucosa around anastomosis in patients treated for the rectal carcinoma by anterior resection appears to identify those with a higher risk of local recurrence. 相似文献
42.
Xiaohua He Edith V Sullivan Roger K Stankovic Clive G Harper Adolf Pfefferbaum 《Neuropsychopharmacology》2007,32(10):2207-2216
The relative roles of alcohol and thiamine deficiency in causing brain damage remain controversial in alcoholics without the Wernicke-Korsakoff syndrome. Experimental control over alcohol consumption and diet are impossible in humans but can be accomplished in animal models. This experiment was designed to differentiate the separate and combined effects on the macro- and ultrastructure of the corpus callosum of thiamine deficiency and voluntary alcohol consumption. Adult male alcohol-preferring (P) rats (9 chronically alcohol-exposed and 9 water controls) received a thiamine-deficient diet for 2 weeks. There were four groups: five rats previously exposed to alcohol were treated with pyrithiamine (a thiamine phosphorylation inhibitor); five rats never exposed to alcohol were treated with pyrithiamine; four alcohol-exposed rats were treated with thiamine; and four rats never exposed to alcohol were treated with thiamine. On day 14, thiamine was restored in all 18 rats; 2 weeks later the 10 pyrithiamine-treated rats received intraperitoneal thiamine. The rats were perfused 61 days post-pyrithiamine treatment at age 598 days. Brains were dissected and weight and volumes were calculated. Sagittal sections were stained to measure white matter structures. The corpus callosum was examined using transmission electron microscopy to determine density of myelinated fibers, fiber diameter, and myelin thickness. The corpus callosum in the alcohol/pyrithiamine group was significantly thinner, had greater fiber density, higher percentage of small fibers, and myelin thinning than in the alcohol/thiamine and water/thiamine groups. Several measures showed a graded effect, where the alcohol/pyrithiamine group had greater pathology than the water/pyrithiamine group, which had greater pathology than the two thiamine-replete groups. Across all 16 rats, thinner myelin sheaths correlated with higher percentage of small fibers. Myelin thickness and axon diameter together accounted for 71% of the variance associated with percentage of small fibers. Significant abnormalities in the alcohol/pyrithiamine group and lack of abnormality in the alcohol-exposed/thiamine-replete group indicate that thiamine deficiency caused white matter damage. The graded abnormalities across the dually to singly treated animals support a compounding effect of alcohol exposure and thiamine depletion, and indicate the potential for interaction between alcohol and thiamine deficiency in human alcohol-related brain damage. 相似文献
43.
目的:探讨奎的平、氯氮平对精神分裂症的疗效及副作用。方法:80例患者随机分为两组,分别应用奎的平或氯氮平治疗6周,采用四级临床疗效评定标准、阳性症状与阴性症状量表(PANSS)、副反应量表(TESS)评定疗效及副反应。结果:奎的平组有效率87.5%,氯氮平组有效率82.5%。治疗第一周末,奎的平组PANSS量表总分较治疗前差异有显著性(P<0.05)。奎的平组副反应低于氯氮平组。结论:奎的平与氯氮平疗效相似,但奎的平起效较快,副反应较轻。 相似文献
44.
45.
46.
PURPOSE: The aim of this retrospective study was to analyze the characteristics of delayed panfacial fractures and evaluate treatment results. PATIENTS AND METHODS: Thirty-three patients with delayed panfacial fractures were treated in the Maxillofacial Trauma Center of Peking University, School and Hospital of Stomatology between 1998 and 2004. Each patient was examined by computed tomography (CT) scans before operation. For those who had no severe opening restriction, dental impressions were taken to fabricate dental casts. For those with severely comminuted fractures, 3-dimensional (3D) models of the facial skeleton were used. Re-establishing the continuity of the mandible was the first step and then used as a platform to reconstruct the maxillary fractures via maxillomandibular fixation after Le Fort I osteotomy. The third step was to restore the mid- and upper-facial width and projection by coronal approach to expose the zygomatic complex and frontal bone/sinus and/or naso-orbito-ethmoid (NOE) fractures. RESULTS: There were 3 types of mandibular fractures that affected the treatment plan: 1) type I, mandibular body/symphysis fracture(s) (17/33, 51.52%); 2) type II, mandibular angle and/or condylar fracture(s) (6/33, 18.18%); and 3) type III, both mandibular body/symphysis and angle/condylar fractures (10/33, 30.30%). Fourteen cases were associated with NOE fractures (42.42%) and 3 cases had frontal sinus fractures (9.1%). Twelve cases had enophthalmos (36.36%) and 3 lost 1 eyeball. The order of treatment was dependent on the mandibular fracture type. For type I fractures, reconstructing the mandibular arch was the first step. For type II fractures, repairing the angle, ascending rami, and condylar areas was the first step. For type III fractures, when both mandibular height and arch were disrupted, freeing the malunited angle or condyle was the first step before restoring the mandibular arch form. Reconstruction of the mandibular height and projection was then carried out. For all 3 types, the second step was to restore the mid- and upper facial width and projection by reducing the zygomatic complex and frontal bone/sinus or NOE fractures. Maxillary fixation across the Le Fort I level was the last step. Le Fort I osteotomy was used for all 33 cases. Bone grafts and soft tissue suspension also were used. Twenty-one cases (63.64%) had good results, 7 (21.21%) cases were acceptable, and 5 (15.15%) were not good. There were 7 cases (21.21%) that still had soft tissue problems that needed secondary operations. CONCLUSIONS: Reconstruction of the mandible first with Le Fort I osteotomy is a good way to treat delayed panfacial fractures. Computed tomography and 3D CT, model surgery, and occasionally 3D models are necessary aids for diagnosis and treatment. Soft tissue problems, including lacerations and asymmetries, were often the factors that caused an unfavorable outcome. 相似文献
47.
Matthias Peltz Tian-Teng He Glenn A Adams Robert Y Chao Michael E Jessen Dan M Meyer 《The Journal of heart and lung transplantation》2005,24(7):896-903
BACKGROUND: Lungs harvested for transplantation are stored while inflated with oxygen, which can serve to support oxidative metabolism. However, strategies aimed at increasing graft metabolism during storage have received little attention. In this study, we added pyruvate to the preservation solution Perfadex and measured the effects on oxidative metabolism and reperfusion lung function. METHODS: Rat lungs were stored for 6 and 24 hours in low-potassium dextran solution at 10 degrees C containing either 5 mmol/liter uniformly carbon-13 (U-(13)C) labeled glucose (Perfadex), 32 mmol/liter 3-(13)C pyruvate (pyruvate), or both (combined). Oxidation of exogenous substrates was measured as the incorporation of (13)C into tricarboxylic acid cycle intermediates by magnetic resonance spectroscopy. Additional groups of lungs with each substrate modification were preserved for 6 or 24 hours and then reperfused. RESULTS: Enrichment of tricarboxylic acid cycle intermediates was low in the Perfadex group (9% at 6 hours and 32% at 24 hours of storage, respectively). In contrast, enrichment was significantly increased in both the pyruvate group (50% and 59%, respectively) and combined group (39% and 54%, respectively) compared with the Perfadex group (p<0.01). Graft function was excellent after 6-hour storage in all groups. All lungs stored for 24 hours exhibited inferior lung function, but oxygenation, pulmonary artery pressures, and airway pressures in the combined group were significantly improved compared with the Perfadex group (p<0.05). CONCLUSIONS: Preservation solution substrate composition influences graft metabolism during storage. The addition of pyruvate to Perfadex increases metabolism during storage and improves reperfusion lung function. 相似文献
48.
Study of pathological morphology in chronic sinusitis] 总被引:1,自引:0,他引:1
OBJECTIVE: To study the pathological characteristics and regularity of chronic sinusitis (CS) in different clinical types, tc estimate the reliability and feasibility of CS classification on the pathologic basis. METHODS: HE, Van Gieson's, alcian blue-periodic acid-schiff(AB-PAS) staining was used to observe the changes of epithelium, to measure the thickness of basement membrane and the area of mucous glands. The ultrastructural changes of pseudostratified ciliated columnar epithelium were observed under transmission electron microscope (TEM) and scanning electron microscope (SEM). RESULTS: The epithelial fiber tissue was increased, the basement membrane was thickened, and the mucous glands were obviously increased in CS under the light microscope. Subepithelial fibrosis and thickened basement membrane were most obviously seen in type III of CS and the hyperplasia of mucous glands was most distinct in type II. Under the TEM, abnormal structure of cilia, decrease of ciliated cells, increase of goblet cells were detected in all three CS types. Under the SEM, the cilia of every types showed the ingravescenced process of pathological changes from slight cilium disorder, disorientation, to desquamation of most cilia and replacement of microvilli. CONCLUSION: There is significant distinction of mucous membrane structure among three types. The Chinese classification of CS has pathological basis, it represents the occurrence, development and regularity of CS, and it can be used as basis in further study, communication and evaluation for surgical effect of CS. 相似文献
49.
根据桂枝汤的效应消除半衰期和表观消除半衰期制订给药方案的探讨 总被引:3,自引:0,他引:3
为探讨药效法估测的效应消除半衰期和效量法估测的表观半衰期对合理制订给药方案的意义和作用,以桂枝汤解热和抗炎的药物动力学实验中所得的相应参数值设计了给药方案,观察了它们在提高药效上的作用。结果表明在给药总剂量相等、首次给药同时开始的情况下,以半衰期设计的给药方案组的药效均明显高于习惯的一次给药组;而以效应消除半衰期设计给药方案组药效增强率又高于以表观半衰期设计的方案组。提示效应消除半衰期比表观半衰期似更有实践意义。 相似文献
50.
北京市东城区和平里社区居民慢性病防治探讨 总被引:3,自引:0,他引:3
王秀清 《中国慢性病预防与控制》1997,5(1):29-30,33
为探索慢性病的防治方法,我们于1989 ̄1994年社区居民中开展了以高血压为主的循环系统慢性病防治课题,经过5年的干预,观察组与对照组居民及接受管理的高血压病人在减少吸烟,饮酒,控制食盐摄入,掌握慢性病防治知识等方面有显著性差异,取得了满意的结果,从而为今后全面开展慢性病防治积累了经验。 相似文献