全文获取类型
收费全文 | 35042篇 |
免费 | 3246篇 |
国内免费 | 1418篇 |
专业分类
耳鼻咽喉 | 146篇 |
儿科学 | 368篇 |
妇产科学 | 334篇 |
基础医学 | 3135篇 |
口腔科学 | 359篇 |
临床医学 | 3771篇 |
内科学 | 6359篇 |
皮肤病学 | 403篇 |
神经病学 | 6406篇 |
特种医学 | 1150篇 |
外国民族医学 | 10篇 |
外科学 | 3101篇 |
综合类 | 5499篇 |
现状与发展 | 6篇 |
一般理论 | 6篇 |
预防医学 | 1284篇 |
眼科学 | 1269篇 |
药学 | 3074篇 |
11篇 | |
中国医学 | 1745篇 |
肿瘤学 | 1270篇 |
出版年
2024年 | 144篇 |
2023年 | 669篇 |
2022年 | 902篇 |
2021年 | 1232篇 |
2020年 | 1339篇 |
2019年 | 1339篇 |
2018年 | 1245篇 |
2017年 | 1262篇 |
2016年 | 1274篇 |
2015年 | 1312篇 |
2014年 | 2084篇 |
2013年 | 2582篇 |
2012年 | 1891篇 |
2011年 | 2023篇 |
2010年 | 1806篇 |
2009年 | 1752篇 |
2008年 | 1839篇 |
2007年 | 1820篇 |
2006年 | 1718篇 |
2005年 | 1588篇 |
2004年 | 1343篇 |
2003年 | 1217篇 |
2002年 | 1106篇 |
2001年 | 844篇 |
2000年 | 724篇 |
1999年 | 537篇 |
1998年 | 493篇 |
1997年 | 450篇 |
1996年 | 405篇 |
1995年 | 368篇 |
1994年 | 293篇 |
1993年 | 248篇 |
1992年 | 246篇 |
1991年 | 242篇 |
1990年 | 158篇 |
1989年 | 156篇 |
1988年 | 137篇 |
1987年 | 127篇 |
1986年 | 102篇 |
1985年 | 144篇 |
1984年 | 99篇 |
1983年 | 70篇 |
1982年 | 76篇 |
1981年 | 94篇 |
1980年 | 44篇 |
1979年 | 45篇 |
1978年 | 34篇 |
1977年 | 24篇 |
1976年 | 18篇 |
1975年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
N. V. Bashmakova G. N. Chistiakova I. A. Gazieva Y. M. Trapeznikova D. O. Mazurov 《Gynecological endocrinology》2015,31(10):31-33
AbstractThis study was undertaken to compare the concentrations of pro- and anti-angiogenic growth factors, nitric oxide (NO) stable metabolites in maternal serum and embryonic left ventricular (LV) isovolumic relaxation time (IRT, ms) during the first trimester in two groups of women: with pregnancy conceived by assisted reproductive technologies (ART, n?=?39) and normally conceived (control group, n?=?68) pregnancy. The concentration of vasoconstrictor endothelin 1 was 45.5 times more in ART than in control group. On the contrary, the concentrations of NO stable metabolites in ART were 1.9 times less than in control women. The assessment of angiogenic suppressors in ART women demonstrates the decrease in s-endoglin concentration was 1.6 times and in soluble receptor to vascular endothelial growth factor concentration was 2.0 times in comparison with control group. There was a significant increase in LV IRT in ART embryos in comparison to control ones. These data suggest significant changes in pro- anti-angiogenic factors balance and increase in vascular impedance in ART-conceived embryos. 相似文献
2.
J?rg Müller Klaus Seppi Nadia Stefanova Werner Poewe Irene Litvan Gregor K Wenning 《Movement disorders》2002,17(5):1041-1045
The frequency and pathophysiology of freezing of gait (FoG) in atypical parkinsonism is unknown. We analysed the frequency of FoG in postmortem-confirmed atypical parkinsonian disorders (APD) comprising corticobasal degeneration (CBD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP). Sixty-six patients with pathologically confirmed APD (CBD, n = 13; DLB, n = 14; MSA, n = 15; PSP, n = 24) formed the basis for a multicenter clinicopathological study. Clinical features at first and last clinical visit were abstracted from patient records on standardized forms following strict instructions. At the first visit (median 36 months after symptom onset), 24% of APD had FoG (CBD, 8%; DLB, 21%; PSP, 25%; MSA, 40%). Logistic regression analysis showed a significant association of FoG and urinary incontinence (P = 0.04) at first visit. At last visit, 47% of APD had FoG (CBD, 25%; PSP, 53%; DLB, 54%; MSA, 54%). Clinicopathological correlation based on routine postmortem examination failed to identify a consistent neuropathological substrate of FoG. This study demonstrates that (1) FoG is common in APD, and (2) urinary incontinence is significantly associated with FoG in these disorders. Whether FoG and urinary incontinence share similar neuropathological substrates remains to be determined by future studies. 相似文献
3.
Directors of nursing at 23 nursing homes with Alzheimer's units in Southwestern Pennsylvania completed a self‐reported survey of 12 questions. Responses from the self‐administered questionnaires (100% response rate) revealed a wide variation in the staff categories assessing the oral health status of newly admitted residents with AD. The respondents described oral examinations that were incomplete when compared to the oral indicators listed in the Minimum Data Set. All nursing homes reported that oral hygiene was provided each day. The number of residents in a facility had a significant effect on the frequency of oral hygiene provided. Only 52% of the facilities reported yearly oral examinations for this population. According to the respondents, dental treatment was typically performed on‐site. The oral health care costs were paid by Medicare, Medicaid, the residents/family members, or by other undescribed resources. Insufficient time, staff, and training, as well as uncooperative behavior, were identified as barriers to optimum oral health care for residents with AD. Additional staff, specialized training, and increased government reimbursement were suggested to improve the oral health care for this group of older adults. For future studies, review of medical records and on‐site evaluation of the oral health care at these facilities should be required to verify the reported practices. 相似文献
4.
Hiroko Ida-Yonemochi Wael Swelam Chikara Saito Takashi Saku 《Journal of oral pathology & medicine》2005,34(1):59-61
A case of angiolipoma occurring in the buccal mucosa of a 69-year-old male is described. The patient had noticed a painless mass in his buccal mucosa for 2 years. The surgically removed tumor, measuring 9 mm in diameter, was mainly located in the submucosal layer with focal expansion into the muscle layer. Histologically, the tumor was well-demarcated and composed of proliferations of mature fat cells and fibrous connective tissue containing many small blood vessels, which were evenly distributed. There was diffuse infiltration of a large number of mast cells, which were immunopositive for vascular endothelial growth factor (VEGF) especially around blood vessels, suggesting that VEGF produced by mast cells in angiolipomas plays an important role in the vascular proliferation in this particular tumor. 相似文献
5.
J. de Rotrou L. Battal-Merlet E. Wenisch C. Chausson E. Bizet F. Dray H. Lenoir A.-S. Rigaud O. Hanon 《European journal of neurology》2007,14(2):144-149
Within the context of early diagnosis of Alzheimer's disease (AD), there is a growing interest in neuropsychological screening tests. Amongst these tests, we focused on the largely used Memory Impairment Screen (MIS). The objective of the present work was to show that adding a 10-min delayed recall to the MIS, improves the test psychometric characteristics in order to detect dementia in the earliest stages. A prospective study was carried out on a cohort of 270 consecutive elderly ambulatory subjects attending the Broca Hospital Memory Clinic: normal controls ( n = 67), mild cognitive impairment subjects ( n = 98) and mildly demented patients [ n = 105, Mini Mental State Examination (MMSE) = 23 ± 4]. This study consisted in testing the advantage of the 10-min delayed recall entitled MIS-D compared with the MIS. At a cut-off score of 6, the MIS-D revealed satisfying psychometric characteristics with a sensitivity of 81% and a specificity of 91%, whilst the MIS alone indicated a sensitivity of 60% and a specificity of 88% in detecting dementia. In demented patients with MMSE score ≥26, MIS-D properties still remained satisfying (sensitivity: 75%, specificity: 92%). MIS-D is a more relevant screening test than MIS alone at very early stages of dementia. 相似文献
6.
血管内皮生长因子在高原脑水肿形成中作用的实验研究 总被引:4,自引:0,他引:4
目的:探讨血管内皮生长因子(VEGF)在高原脑水肿形成中的作用。方法:建立大鼠模拟高原模型,应用脑干湿重比率法定量脑水肿情况、应用荧光素钠透过率测定BBB通透性、应用实时荧光定量RT-PCR法检测脑组织VEGF mRNA含量以及应用蛋白印迹法半定量脑组织VEGF含量。结果:大鼠在高原24 h后脑组织含水率明显增高(P<0.05),荧光素钠透过率显著增加(P<0.01);VEGF mRNA转录及其表达显著增高(P<0.001)。结论:VEGF表达在高原脑水肿形成中起重要作用。 相似文献
7.
目的观察葛根素对血管性痴呆(VaD)患者认知功能和听觉事件相关电位P300的影响。方法将70例VaD患者随机分成两组各35例,葛根素治疗组和对照组。应用简易精神状态检查量表(MMSE)评定两组患者治疗前后认知功能状况,并进行治疗前后P300检查。同时记录药物不良反应。结果两组各35例进入结果分析。治疗前两组MMSE评分、P300的潜伏期及波幅差异无显著性(均P〉0.05)。治疗14d、30d时,两组MMSE评分显著提高(均P〈0.01),P300潜伏期均有缩短,波幅均有提高(葛根素组P〈0.01,对照组P〈0.05);治疗后14d时认知功能改善葛根素组明显优于对照组(总有效率分别为91.4%,71.4%)(P〈0.05)。两组治疗期间无严重不良反应。结论葛根素能够改善VaD患者的认知功能,这可能与葛根素的扩血管、脑保护作用有关。 相似文献
8.
Background: We evaluated the endoscopic microvascular architecture of the gastric mucosa in portal hypertension patients using the prototype of narrow band imaging (NBI). Material and Methods: The study included 103 Helicobacter pylori‐negative patients with chronic liver disease (22 without portal hypertension (group 1), 81 with portal hypertension (group 2)). Results: (i) Abnormality of collecting venules, reddening mucosa, red spots, a mosaic‐like pattern, and gastric antral vascular ectasia (GAVE) were observed on the gastric mucosa, and an obscure change in collecting venules (73% vs 14%; P < 0.001), reddening mucosa (49% vs 5%; P < 0.001), red spots (36% vs 5%; P < 0.01) and a mosaic‐like pattern (40% vs 5%; P < 0.01) were more frequently observed in group 2 than in group 1. (ii) On magnifying endoscopy with NBI, the mucosa with an obscure change in collecting venules was demonstrated as dilation of the capillaries surrounding the gastric pits in various degrees, and reddening mucosa was observed as extended and swollen gastric pits and various degrees of dilated and convoluted capillaries surrounding the gastric pits. Red spots were demonstrated as extended and swollen gastric pits, dilated and convoluted capillaries surrounding the gastric pits, and intramucosal hemorrhage around these capillaries. GAVE was recognized as partial and marked dilatation of the capillaries surrounding the gastric pits. Conclusion: Abnormality of collecting venules, swelling of gastric pits, dilatation of capillaries surrounding the gastric pits, intramucosal hemorrhage around capillaries, and partial and marked dilatation of the capillaries were observed on the gastric mucosa in portal hypertension patients. 相似文献
9.
益气复智颗粒对多发脑梗死性痴呆模型大鼠脑组织细胞凋亡的影响 总被引:1,自引:0,他引:1
目的 观察益气复智颗粒对多发脑梗死性痴呆模型大鼠脑皮质形态学、细胞凋亡的影响。方法 采用颈内动脉注射血栓的方法,复制多发梗死性痴呆大鼠模型,观察益气复智颗粒12.42g/kg分别于手术前、手术前后、手术后灌胃对实验动物脑皮质形态学、细胞凋亡的影响。结果 益气复智颗粒能使脑缺血后脑内神经细胞凋亡数目下降。结论 益气复智颗粒具有较好的保护脑神经元,阻断脑缺血致神经细胞死亡病理过程的作用。 相似文献
10.