全文获取类型
收费全文 | 449064篇 |
免费 | 41296篇 |
国内免费 | 29764篇 |
专业分类
耳鼻咽喉 | 3344篇 |
儿科学 | 5855篇 |
妇产科学 | 5106篇 |
基础医学 | 50184篇 |
口腔科学 | 7417篇 |
临床医学 | 62291篇 |
内科学 | 62653篇 |
皮肤病学 | 4913篇 |
神经病学 | 22932篇 |
特种医学 | 16268篇 |
外国民族医学 | 244篇 |
外科学 | 41711篇 |
综合类 | 80384篇 |
现状与发展 | 95篇 |
一般理论 | 52篇 |
预防医学 | 32773篇 |
眼科学 | 12591篇 |
药学 | 47876篇 |
503篇 | |
中国医学 | 28044篇 |
肿瘤学 | 34888篇 |
出版年
2024年 | 4644篇 |
2023年 | 6536篇 |
2022年 | 16412篇 |
2021年 | 20982篇 |
2020年 | 16658篇 |
2019年 | 13808篇 |
2018年 | 14214篇 |
2017年 | 13489篇 |
2016年 | 12596篇 |
2015年 | 19358篇 |
2014年 | 24146篇 |
2013年 | 22217篇 |
2012年 | 32906篇 |
2011年 | 37033篇 |
2010年 | 24593篇 |
2009年 | 20069篇 |
2008年 | 25027篇 |
2007年 | 25067篇 |
2006年 | 24261篇 |
2005年 | 23214篇 |
2004年 | 15649篇 |
2003年 | 15140篇 |
2002年 | 12639篇 |
2001年 | 10208篇 |
2000年 | 10014篇 |
1999年 | 10305篇 |
1998年 | 6560篇 |
1997年 | 6478篇 |
1996年 | 5002篇 |
1995年 | 4653篇 |
1994年 | 3948篇 |
1993年 | 2623篇 |
1992年 | 3107篇 |
1991年 | 2707篇 |
1990年 | 2297篇 |
1989年 | 2011篇 |
1988年 | 1726篇 |
1987年 | 1539篇 |
1986年 | 1318篇 |
1985年 | 955篇 |
1984年 | 613篇 |
1983年 | 503篇 |
1982年 | 324篇 |
1981年 | 359篇 |
1980年 | 289篇 |
1979年 | 268篇 |
1978年 | 156篇 |
1977年 | 141篇 |
1976年 | 98篇 |
1974年 | 112篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Zhu L Fratiglioni L Guo Z Basun H Corder EH Winblad B Viitanen M 《Stroke; a journal of cerebral circulation》2000,31(1):53-60
BACKGROUND AND PURPOSE: Both stroke and the apolipoprotein E (APOE) epsilon4 allele increase the risk of dementia. However, the interaction between stroke and APOE on dementia is still unclear. We addressed this topic by using a longitudinal design. METHODS: We followed up a community cohort of 1301 subjects aged >/=75 years, who did not have dementia at baseline. Among them, 92 subjects had a history of stroke (from 3 months to 16 years before baseline interview). After the 3-year follow-up, 224 dementia cases had been diagnosed. During the period of follow-up, 91 subjects had a first occurrence of stroke (incident stroke). The APOE genotype was known for 985 subjects. Cox proportional hazards regression models were constructed to estimate the risk for dementia in terms of relative risks (RRs) for stroke and the APOE epsilon4 allele, with adjustment for age, sex, education, systolic blood pressure, antihypertensive medication use, and heart disease. RESULTS: In the entire study population, RRs for dementia related to history of stroke and incident stroke were 1.7 (95% CI, 1.1 to 2.6) and 2.4 (95% CI, 1.6 to 3.5), respectively, after adjustment for all potential confounders. Subjects with stroke that occurred within 3 years before baseline had RR of 2.4 (95% CI, 1.4 to 4.2), whereas those with stroke occurring >3 years before baseline had RR of dementia of 1.1 (95% CI, 0.6 to 2.3). Among those with APOE information, individuals with only history of stroke (that occurred within 3 years before baseline) had RR of 3.1 (95% CI, 1.4 to 6.6), individuals with only the APOE epsilon4 allele had RR of 1.7 (95% CI, 1.1 to 2.5), and individuals with both factors had RR of 5.3 (95% CI, 2.1 to 13.4). The corresponding figures when incident stroke was examined instead of history of stroke were 2.3 (95% CI, 1.3 to 4.1), 1.7 (95% CI, 1.1 to 2.4), and 4.6 (95% CI, 2.0 to 10.6), respectively. The RR of interaction term for history of stroke and APOE epsilon4 was 1.1 (95% CI, 0.3 to 3.8; P=0.8). The corresponding figure was 1.2 (95% CI, 0.4 to 4.4; P=0.7) for incident stroke and APOE epsilon4. Furthermore, the RRs of dementia without any stroke and dementia with stroke in relation to APOE epsilon4 were 1.6 (95% CI, 1.1 to 2.3) and 1.2 (95% CI, 0.6 to 2.4), respectively. In addition, the APOE epsilon4 allele was not significantly related to the occurrence of stroke (RR=0.8; 95% CI, 0.5 to 1.5). CONCLUSIONS: A relatively fresh stroke is a risk factor for dementia. APOE epsilon4 increases the risk of dementia without stroke but not dementia with stroke. Our data do not support a multiplicative effect of stroke and the APOE epsilon4 allele on the risk of dementia. However, both factors seem to have an additive effect on the risk of dementia. The APOE epsilon4 allele does not increase the risk of stroke in this Swedish elderly population. 相似文献
992.
Campbell BC Li QX Culvenor JG Jäkälä P Cappai R Beyreuther K Masters CL McLean CA 《Neurobiology of disease》2000,7(3):192-200
The alpha-synuclein (alpha SN) protein is thought to play a central role in the pathogenesis of neurodegenerative diseases where it aggregates to form intracellular inclusions. We have used Western blotting to examine the expression levels and solubility of alpha SN in brain homogenates from dementia with Lewy bodies (DLB), Parkinson's disease (PD), Alzheimer's disease (AD), and normal controls using samples from the parahippocampus/transentorhinal cortex. Compared to controls, DLB brains accumulate significantly greater amounts of sodium dodecyl sulfate (SDS)-soluble and SDS-insoluble alpha SN but levels of TBS-soluble alpha SN did not change. Levels of synaptophysin, a marker of synaptic integrity, were significantly lower in DLB cases than in normal aged controls regardless of whether concurrent changes of AD were present. This limbic synaptic dysfunction may contribute to cognitive impairment in DLB. Whether aggregated alpha SN is a cause or effect of the disease process in DLB and PD remains to be determined, but the presence of aggregated alpha SN is consistent with a pathogenesis similar to that associated with aggregates of Abeta amyloid in AD. 相似文献
993.
A large number of studies have examined both the epidemiology and neuropsychiatric manifestations of dementia among older
adults. However, there is a relative dearth of studies focusing on ethnic minority elders in the United States. This article
reviews the existing empiric literature in the area of ethnicity and dementia. For the purpose of this paper, the focus will
be on Hispanics and black Americans, the two most prevalent ethnic minority populations in the United States. This review
includes discussion of terminology issues, diagnosis, epidemiology, and clinical features, in addition to caregiver issues. 相似文献
994.
Rosen RC 《Current psychiatry reports》2000,2(3):189-195
Sexual dysfunctions are highly prevalent, affecting about 43% of women and 31% of men. Hypoactive sexual desire disorder has been reported in approximately 30% of women and 15% of men in population-based studies, and is associated with a wide variety of medical and psychologic causes. Sexual arousal disorders, including erectile dysfunction in men and female sexual arousal disorder in women, are found in 10% to 20% of men and women, and is strongly age-related in men. Orgasmic disorder is relatively common in women, affecting about 10% to 15% in community-based studies. In contrast, premature ejaculation is the most common sexual complaint of men, with a reporting rate of approximately 30% in most studies. Finally, sexual pain disorders have been reported in 10% to 15% of women and less than 5% of men. In addition to their widespread prevalence, sexual dysfunctions have been found to impact significantly on interpersonal functioning and overall quality of life in both men and women. 相似文献
995.
996.
目的 分离和测定非那甾胺中5β-异构体杂质。方法 高效液相色谱法,色谱柱为DiamonsilTMC18柱(4.6 mm×200 mm,5μm),流动相为乙腈-四氢呋喃-水(3:1:8),流速为1.5 mL·min-1,检测波长为210nm,柱温25℃。结果 非那甾胺与5β-异构体能有效分离,两者最低检测浓度均为0.05μg·mL-1。结论 本法操作简便,重现性好,可有效控制非那甾胺的质量。 相似文献
997.
目的 用群体药代动力(PPK)模型和贝叶斯法预测血药浓度。方法 用癫痫儿童丙戊酸钠PPK模型和USC~*PACK软件中的贝叶斯程序,对100例新癫痫患儿丙戊酸钠的血药浓度进行预测。将预测值与实测值做配对t检验,相关和回归分析,计算平均预测误差、预测误差的百分比、不同预测误差百分比的符合率及其95%可信区间、构成比和评价预测的准确程度。结果 预测值与实测值的相关系数为0.99,P<0.001,线性回归Y_(OBS)=0.99)Y_(PRED),决定系数为0.98,P<0.001;平均预测误差为-0.43μg·mL~(-1),预测误差百分比分别为5%,10%,15%,20%,25%,30%的符合率为62%,74%,82%,85%,89%,93%。结论 PPK模型和贝叶斯法可准确预测丙戊酸钠稳态血药浓度。 相似文献
998.
中西医结合对重症脑外伤昏迷病人促苏醒疗效观察 总被引:14,自引:0,他引:14
目的 :探讨醒脑开窍疗法对治疗重症颅脑损伤患者促苏醒作用以及对预后的影响。方法 :将 80例颅脑损伤患者 (GCS≤ 8)随机分成 2组 ,治疗组 4 0例 (在常规治疗基础上加用中药针刺疗法 ) ;对照组 4 0例。两组于伤后 1月按GCS预后评分评定预后 ,两组在促醒后 1月内意识好转率作一比较。结果 :治疗组预后恢复良好为 87 5 % ,显著高于对照组 6 2 5 % ,P <0 0 1;两组病死率差异无显著性意义 (P >0 0 5 )。治疗组 1月内清醒 32例 ,对照组 2 0例 ,P <0 0 1。结论 :中西医结合疗法在治疗重症脑外伤昏迷患者时 ,能加速促醒和提高生存质量。 相似文献
999.
腰痹舒治疗腰椎间盘突出症临床疗效分析 总被引:15,自引:0,他引:15
用中药腰痹舒治疗腰椎间盘突出症 3 1例 ,治愈 2 8例 ,有效 3例。治疗后随访 6~ 1 8个月 ,无 1例复发。与牵引、按摩、秋水仙碱内服对照组比较 ,中药疗效显著优于对照组 (P<0 .0 5 )。经 CT检查 ,腰痹舒治愈后椎间盘的后突压迫、粘连均有不同程度的解除。提出可根据症状、体征将腰椎间盘出症的腰腿痛分为 1 0级。作为判断病情和疗程的主要指标。其治疗宜通经、化瘀散寒为主。 相似文献
1000.
电针对去势大鼠外周血淋巴细胞雌激素受体影响的研究 总被引:4,自引:0,他引:4
目的 从生殖内分泌 -免疫网络角度探讨电针治疗围绝经期综合征的作用机制。方法 以去势大鼠为实验对象 ,取双侧三阴交、太溪、后三里穴 ,采用放射免疫法和流式细胞分析技术 ,观察电针治疗对去势大鼠血清雌激素 (E2 )、促黄体生成素 (LH)、促卵泡生成素(FSH)及外周血淋巴细胞内雌激素受体 (ER)水平的影响。结果 电针可使去势大鼠血清E2 明显升高 ,LH及FSH明显下降 ,外周血淋巴细胞内ER明显升高 ,与造模组比较有显著性差异。结论 电针可明显改善去势大鼠的生殖内分泌功能 ,并能调节免疫细胞的雌激素受体表达。 相似文献