全文获取类型
收费全文 | 52086篇 |
免费 | 5700篇 |
国内免费 | 1753篇 |
专业分类
耳鼻咽喉 | 540篇 |
儿科学 | 1006篇 |
妇产科学 | 464篇 |
基础医学 | 4829篇 |
口腔科学 | 484篇 |
临床医学 | 6298篇 |
内科学 | 8562篇 |
皮肤病学 | 596篇 |
神经病学 | 11586篇 |
特种医学 | 1429篇 |
外国民族医学 | 11篇 |
外科学 | 3901篇 |
综合类 | 7253篇 |
现状与发展 | 6篇 |
一般理论 | 6篇 |
预防医学 | 2612篇 |
眼科学 | 1789篇 |
药学 | 4270篇 |
24篇 | |
中国医学 | 2226篇 |
肿瘤学 | 1647篇 |
出版年
2024年 | 51篇 |
2023年 | 1130篇 |
2022年 | 1169篇 |
2021年 | 2194篇 |
2020年 | 2432篇 |
2019年 | 2474篇 |
2018年 | 2334篇 |
2017年 | 2347篇 |
2016年 | 2264篇 |
2015年 | 2189篇 |
2014年 | 3512篇 |
2013年 | 4525篇 |
2012年 | 2975篇 |
2011年 | 3024篇 |
2010年 | 2600篇 |
2009年 | 2528篇 |
2008年 | 2584篇 |
2007年 | 2524篇 |
2006年 | 2337篇 |
2005年 | 2025篇 |
2004年 | 1726篇 |
2003年 | 1579篇 |
2002年 | 1380篇 |
2001年 | 1065篇 |
2000年 | 899篇 |
1999年 | 646篇 |
1998年 | 529篇 |
1997年 | 466篇 |
1996年 | 432篇 |
1995年 | 457篇 |
1994年 | 374篇 |
1993年 | 330篇 |
1992年 | 318篇 |
1991年 | 302篇 |
1990年 | 209篇 |
1989年 | 205篇 |
1988年 | 177篇 |
1987年 | 177篇 |
1986年 | 147篇 |
1985年 | 188篇 |
1984年 | 139篇 |
1983年 | 91篇 |
1982年 | 102篇 |
1981年 | 114篇 |
1980年 | 57篇 |
1979年 | 61篇 |
1978年 | 44篇 |
1977年 | 29篇 |
1976年 | 26篇 |
1975年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Tim Holland 《The Hastings Center report》2023,53(1):50-51
This letter responds to the article “On the Authority of Advance Euthanasia Directives for People with Severe Dementia: Reflections on a Dutch Case,” by Henri Wijsbek and Thomas Nys, in the September-October 2022 issue of the Hastings Center Report. 相似文献
2.
3.
认知障碍是指记忆、语言、理解和判断等一个或多个方面的功能障碍,包括轻度认知障碍和各种类型的痴呆症。痴呆症是认知障碍最严重的表现,是一种导致患者日常生活、社会交往和工作能力发生显著变化的综合征。阿尔茨海默病(AD)是最常见的痴呆症类型,其次是血管性痴呆(VD)和其他神经退行性痴呆[1]。已知年龄与认知功能的退化密切相关。 相似文献
4.
目的探讨麻痹性痴呆(GPI)患者脑血流量(CBF)特点及其与认知障碍的相关性。 方法纳入2018年1月至2019年12月于首都医科大学附属北京地坛医院就诊的GPI患者18例和健康体检者18例(健康对照组),采用蒙特利尔认知评估量表评定认知功能。采用磁共振动脉自旋标记技术扫描评估其各个脑区CBF,并进一步应用Spearman相关分析CBF异常区域与认知功能的相关性。 结果GPI患者蒙特利尔认知评估量表评分低于健康对照组[(16.00 ± 7.19)vs. (27.90 ± 1.21):t =-7.853、P < 0.001)]。18例GPI患者中,头颅MRI正常5例,脑白质病变1例,脑萎缩9例,3例患者同时存在脑萎缩和脑白质病变。健康对照组头颅MRI均未见异常。GPI患者脑13、14、28、37、38、41、42、43、44、46、48、49、50、51、52、69、70、77、78、83、84、88、109、117、165、166、167、168、169、177、178、179、187、188、211、212、213、214、215、216、219、223、227、237和238区CBF显著高于健康对照组(P均< 0.001)。GPI患者认知障碍中的注意力障碍与脑69、70、77、78、166和168区CBF异常有一定的负相关性(r =-0.476、P = 0.046,r =-0.487、P = 0.034,r =-0.604、P = 0.008,r = -0.545、P = 0.019,r =-0.544、P = 0.02,r =-0.522、P = 0.026)。 结论GPI患者存在全脑血流量升高。GPI患者认知功能障碍中的注意力障碍可能与局部脑区血流量升高有一定相关性。局部CBF越高,注意力障碍越严重。这可能也是GPI发病机制之一。 相似文献
5.
《Journal of the American Medical Directors Association》2022,23(4):601-607.e2
ObjectivePrevious epidemiologic studies have suggested an association between appendectomy and Parkinson's disease. The aim of the current study was to examine the risk of Alzheimer's disease (AD) and other types of dementia following appendicitis or appendectomy for appendicitis.DesignPopulation-based cohort study.Setting and participantsWe used claims data from the Taiwan National Health Insurance Research Database. Participants aged ≥45 years with acute appendicitis or who received appendectomy for appendicitis were enrolled and followed up for more than 15 years. Cases and controls underwent 1:1 matching by age, sex, index date, and dementia-related comorbidities.MethodsThe primary outcome was AD, and secondary outcomes included other dementia types. Adjusted hazard ratios (aHRs) were calculated, and a competing risk regression model was created. The E value for causality of evidence was calculated.ResultsPatients developing appendicitis (0.6% vs 0.1%, P = .005) and those receiving appendectomy for appendicitis (0.4% vs 0.1%, P = .003) had higher incidences of AD than the controls during the follow-up period. A Cox regression analysis with adjustment for potential confounders showed that patients with appendicitis [aHR 6.68, 95% confidence interval (CI) 1.84-24.48] and those receiving appendectomy for appendicitis (aHR 5.01, 95% CI 1.33-18.85) were more likely to develop AD than the controls. These 2 groups also had higher risks for unspecified dementia and all types of dementia but not for vascular dementia than the controls. The age at dementia diagnosis was 88.51 years in the controls; however, among people who developed dementia following appendicitis, the mean age at diagnosis was 70.18 years, and dementia occurred 5.84 years after appendicitis. The competing risk regression models and the E values support the study findings.Conclusions and implicationsAfter recovery from appendicitis, these patients should be followed up for signs of AD. 相似文献
6.
《Journal of vascular and interventional radiology : JVIR》2022,33(10):1213-1221.e5
PurposeTo investigate the pharmacokinetics (PK) and early effects of conventional transarterial chemoembolization (TACE) using sorafenib and doxorubicin on tumor necrosis, hypoxia markers, and angiogenesis in a rabbit VX2 liver tumor model.Materials and MethodsVX2 tumor-laden New Zealand White rabbits (N = 16) were divided into 2 groups: 1 group was treated with hepatic arterial administration of ethiodized oil and doxorubicin emulsion (DOX-TACE), and the other group was treated with ethiodized oil, sorafenib, and doxorubicin emulsion (SORA-DOX-TACE). Animals were killed within 3 days of the procedure. Levels of sorafenib and doxorubicin were measured in blood, tumor, and adjacent liver using mass spectrometry. Tumor necrosis was determined by histopathological examination. Intratumoral hypoxia-inducible factor (HIF) 1α, vascular endothelial growth factor (VEGF), and microvessel density (MVD) were determined by immunohistochemistry.ResultsThe median intratumoral concentration of sorafenib in the SORA-DOX-TACE group was 17.7 μg/mL (interquartile range [IQR], 7.42–33.5 μg/mL), and its maximal plasma concentration (Cmax) was 0.164 μg/mL (IQR, 0.0798–0.528 μg/mL). The intratumoral concentration and Cmax of doxorubicin were similar between the groups: 4.08 μg/mL (IQR, 3.18–4.79 μg/mL) and 0.677 μg/mL (IQR, 0.315–1.23 μg/mL), respectively, in the DOX-TACE group and 1.68 μg/mL (IQR, 0.795–4.08 μg/mL) and 0.298 μg/mL (IQR, 0.241–0.64 μg/mL), respectively, in the SORA-DOX-TACE group. HIF-1α expression was increased in the SORA-DOX-TACE group than in the DOX-TACE group. Tumor volume, tumor necrosis, VEGF expression, and MVD were similar between the 2 groups.ConclusionsThe addition of sorafenib to DOX-TACE delivered to VX2 liver tumors resulted in high intratumoral and low systemic concentrations of sorafenib without altering the PK of doxorubicin. 相似文献
7.
目的 探究补肾活血方对血管性痴呆(Vascular Dementia, VD)大鼠模型自噬的影响。方法 52周龄SD雄性大鼠50只,随机分为假手术组(Sham组)、模型组(VD组)、模型+补肾活血方组(BSHX组)、模型+雷帕霉素组(Rap组)和模型+3-甲基腺嘌呤组(3-MA组),每组10只大鼠。除Sham组外其余各组采用两血管阻断法(2-VO)建立VD模型。BSHX组中药灌胃治疗28天;自噬干预组于造模前30 min侧脑室给药。运用Morris水迷宫测试各组大鼠的学习记忆能力;通过尼氏染色和透射电子显微镜(Transmission electron microscope,TEM)观察大鼠海马区病理形态及自噬变化;采用蛋白免疫印迹(Western blot)法和反转录实时荧光定量PCR(RT-qPCR)检测大鼠海马Beclin-1、P62以及微管相关蛋白1轻链3(LC3)蛋白及mRNA表达情况。结果 与VD组比较,BSHX组大鼠学习记忆能力显著提升(P<0.05),镜下观察BSHX组和3-MA组的细胞形态及数量均有改善,自噬小体鲜见,Beclin-1以及LC3蛋白和mRNA表达水平显著降低(P<0.05),P62蛋白和mRNA表达水平明显升高(P<0.05)结论 补肾活血方可以降低VD大鼠海马区Beclin-1和LC3蛋白及mRNA的表达,提高P62的表达,通过抑制自噬的发生,减轻对神经细胞的损伤,改善学习记忆能力。 相似文献
9.