全文获取类型
收费全文 | 39458篇 |
免费 | 4630篇 |
国内免费 | 2783篇 |
专业分类
耳鼻咽喉 | 367篇 |
儿科学 | 751篇 |
妇产科学 | 436篇 |
基础医学 | 3943篇 |
口腔科学 | 902篇 |
临床医学 | 5196篇 |
内科学 | 4949篇 |
皮肤病学 | 373篇 |
神经病学 | 1463篇 |
特种医学 | 1651篇 |
外国民族医学 | 10篇 |
外科学 | 3208篇 |
综合类 | 8515篇 |
现状与发展 | 11篇 |
一般理论 | 1篇 |
预防医学 | 3552篇 |
眼科学 | 1076篇 |
药学 | 4649篇 |
56篇 | |
中国医学 | 2829篇 |
肿瘤学 | 2933篇 |
出版年
2024年 | 91篇 |
2023年 | 714篇 |
2022年 | 1500篇 |
2021年 | 2212篇 |
2020年 | 2043篇 |
2019年 | 1369篇 |
2018年 | 1431篇 |
2017年 | 1428篇 |
2016年 | 1282篇 |
2015年 | 2075篇 |
2014年 | 2448篇 |
2013年 | 2420篇 |
2012年 | 3408篇 |
2011年 | 3498篇 |
2010年 | 2484篇 |
2009年 | 2002篇 |
2008年 | 2169篇 |
2007年 | 2136篇 |
2006年 | 2000篇 |
2005年 | 1807篇 |
2004年 | 1145篇 |
2003年 | 1032篇 |
2002年 | 799篇 |
2001年 | 680篇 |
2000年 | 651篇 |
1999年 | 697篇 |
1998年 | 439篇 |
1997年 | 442篇 |
1996年 | 343篇 |
1995年 | 351篇 |
1994年 | 265篇 |
1993年 | 178篇 |
1992年 | 164篇 |
1991年 | 187篇 |
1990年 | 147篇 |
1989年 | 151篇 |
1988年 | 119篇 |
1987年 | 113篇 |
1986年 | 93篇 |
1985年 | 84篇 |
1984年 | 50篇 |
1983年 | 43篇 |
1982年 | 45篇 |
1981年 | 34篇 |
1980年 | 20篇 |
1979年 | 16篇 |
1978年 | 6篇 |
1977年 | 26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 15 毫秒
91.
Lori F. Maxfield Peter Abbink Kathryn E. Stephenson Erica N. Borducchi David Ng'ang'a Marinela M. Kirilova Noelix Paulino Michael Boyd Paul Shabram Qian Ruan Mayank Patel Dan H. Barouch 《Clinical and Vaccine Immunology : CVI》2015,22(11):1166-1175
Replication-competent adenovirus (rcAd)-based vaccine vectors may theoretically provide immunological advantages over replication-incompetent Ad vectors, but they also raise additional potential clinical and regulatory issues. We produced replication-competent Ad serotype 26 (rcAd26) vectors by adding the E1 region back into a replication-incompetent Ad26 vector backbone with the E3 or E3/E4 regions deleted. We assessed the effect of vectorization on the replicative capacity of the rcAd26 vaccines. Attenuation occurred in a stepwise fashion, with E3 deletion, E4 deletion, and human immunodeficiency virus type 1 (HIV-1) envelope (Env) gene insertion all contributing to reduced replicative capacity compared to that with the wild-type Ad26 vector. The rcAd26 vector with E3 and E4 deleted and containing the Env transgene exhibited 2.7- to 4.4-log-lower replicative capacity than that of the wild-type Ad26 in vitro. This rcAd26 vector is currently being evaluated in a phase 1 clinical trial. Attenuation as a result of vectorization and transgene insertion has implications for the clinical development of replication-competent vaccine vectors. 相似文献
92.
Spherical MCM-48 mesoporous sieve co-doped with vanadium and iron was successfully synthesized via one-step hydrothermal method. The material was characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, inductively coupled plasma (ICP), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV-vis spectra, and X-ray photoelectron spectra (XPS) techniques. Results indicated that the V-Fe-MCM-48 showed an ordered 3D cubic mesostructure with spherical morphology, narrow pore size distribution and high specific surface area. Most of vanadium and iron atoms existing as tetrahedral V4+ and Fe3+ species were co-doped into the silicate framework. The particle sizes of V-Fe-MCM-48 were smaller and the specific area was much higher than those of of V-MCM-48. Additionally, the synthesized V-Fe-MCM-48 exhibited improved hydrothermal stability compared with the pure MCM-48. 相似文献
93.
目的探讨血清胃泌素17(G17)水平与胃癌及癌前疾病的相关性。方法纳入2011年-2012年于中国医科大学附属第一医院消化内科就诊患者1 336例,应用酶联免疫吸附测定法(ELISA)检测血清G17水平及幽门螺杆菌Ig G(H.pylori-Ig G)抗体滴度。结果在60岁以上、H.pylori-Ig G阴性、萎缩性胃炎(AG)组及胃癌(GC)组中,女性患者血清G17水平均显著高于男性患者(P0.05)。在非AG组及异型增生(GD)组中,H.pylori阳性患者血清G17水平显著高于H.pylori阴性患者(P0.05)。在所有患者中,与SG组相比,GC、胃黏膜糜烂(GE)和胃溃疡(GU)组血清G17水平显著升高(P0.05);与浅表性胃炎伴糜烂(SG-IM)组相比,GD、GC、GE和GU组G17水平显著升高(P0.05);与AG组相比,GC、GE和GU组G17水平显著升高(P0.05)。在H.pylori阴性患者中,与SG组相比,GC组和GU组血清G17水平显著升高(P0.05);与SG-IM组相比,AG、GC、GE和GU组G17水平显著升高(P0.05);与GD组相比,GU组血清G17水平显著升高(P=0.007)。结论血清G17水平受患者性别及H.pylori感染等相关因素的影响,在从SG、SG-IM、AG、GD到GC的动态变化过程中呈逐渐升高的趋势,且GC患者较其他疾病明显升高。血清G17可能作为胃癌的生物标志物,有望成为胃癌筛查及早期诊断的一个重要观测指标。 相似文献
94.
95.
目的研究低氧刺激慢性鼻窦炎伴鼻息肉(CRSwNP)与正常鼻黏膜上皮细胞炎性因子的变化与异同,探讨其在CRSwNP发病机制中的作用。方法选择2015年6月至2018年1月在吉林大学中日联谊医院就诊的68例CRSwNP患者,其中男性36例,女性32例,年龄(45.2±12.5)岁(xˉ±s,下同),患者的鼻息肉黏膜纳入慢性鼻窦炎鼻息肉组(CRS-NP组),下鼻甲黏膜纳入慢性鼻窦炎下鼻甲组(CRS-IT组),并根据组织病理学结果进一步分成嗜酸粒细胞浸润及非浸润两种类型,即嗜酸粒细胞浸润性鼻息肉组(Eos-NP组,n=34)、非嗜酸粒细胞浸润性鼻息肉组(Non-Eos-NP组,n=34)、嗜酸粒细胞浸润性鼻息肉患者的下鼻甲组(Eos-IT组,n=20)和非嗜酸粒细胞浸润性鼻息肉患者的下鼻甲组(Non-Eos-IT组,n=20);同期25例鼻窦囊肿或鼻中隔偏曲患者的下鼻甲黏膜作为对照组(n=25),其中男性14例,女性11例,年龄(42.8±10.2)岁。免疫组织化学染色分析各组黏膜上皮组织中白细胞介素(IL)17A、干扰素γ(IFN-γ)、肿瘤坏死因子α(TNF-α)与乏氧诱导因子(hypoxia-inducible factor 1α,HIF-1α)的表达情况。酶联免疫吸附试验检测低氧刺激0、24和48 h后各组原代鼻黏膜上皮细胞分泌IL-17A、IFN-γ和TNF-α的差异;免疫荧光、固态光源高内涵与免疫印记实验检测原代鼻黏膜上皮细胞HIF-1α的表达情况。应用SPSS 17.0软件对数据进行统计学分析,采用双向方差分析作为主要统计学方法。结果免疫组织化学染色结果显示,IL-17A和TNF-α在对照组中表达最高(光密度值分别为0.37±0.03、0.53±0.02),IFN-γ和HIF-1α在Eos-IT组中表达最高(光密度值分别为0.47±0.03、0.39±0.02)。未接受低氧刺激时,IL-17A与TNF-α在对照组中水平较低;低氧刺激48 h后,对照组的IL-17A与TNF-α分泌量明显高于其他各组。未接受低氧刺激时,Eos-NP组分泌的IFN-γ明显高于对照组[(13.7±1.3)pg/ml比(11.1±1.6)pg/ml,P<0.05];低氧刺激48 h后,IFN-γ在对照组和Eos-NP组中的分泌量没有显著区别。对照组与CRS-IT组表达的HIF-1α随低氧时间延长而增加,Eos-NP组与Non-Eos-NP组表达的HIF-1α随低氧时间延长而减少。对照组与CRS-IT组HIF-1α主要表达于鼻黏膜上皮细胞的细胞质内,CRS-NP组HIF-1α主要表达于鼻黏膜上皮细胞的细胞核内。结论低氧刺激下,CRSwNP患者的鼻息肉、下鼻甲与正常鼻黏膜上皮细胞中IL-17A、TNF-α、IFN-γ的分泌以及HIF-1α的表达水平存在差异,且呈现不同的亚细胞定位,提示其可能参与了CRSwNP发病相关基因的转录与调控。 相似文献
96.
目的探讨脑卒中患者急性应激障碍发生现状及影响因素。方法采用斯坦福急性应激反应问卷对349例脑卒中住院患者进行调查。结果共163例(46.70%)患者发生急性应激障碍;Logistic回归分析结果显示,患者性格、是否存在偏瘫及是否吞咽功能障碍是脑卒中患者发生急性应激障碍的主要影响因素(P0.05,P0.01)。结论脑卒中患者急性应激障碍发生率较高,内向性格及存在偏瘫和吞咽功能障碍的患者更容易发生急性应激障碍。医护人员应及时为高危患者提供个体化治疗及预见性护理,防止脑卒中患者发生急性应激障碍。 相似文献
97.
98.
Hong-Sheng Zhang Qian Liu Chun-Mei Piao Yan Zhu Qiang-Qiang Li Jie Du Hong Gu 《The Canadian journal of cardiology》2019,35(12):1851-1856
BackgroundThe relationship between clinical outcomes and gene mutations in Chinese pediatric patients with idiopathic and heritable pulmonary arterial hypertension (PAH) is unclear.MethodsWe retrospectively studied the clinical characteristics and outcomes of pediatric patients who visited Beijing Anzhen Hospital from September 2008 to December 2018.ResultsEighty-two pediatric patients were included. Forty-two gene mutations were identified in 41 patients (50%), including 25 mutations in BMPR2, 5 mutations in ACVRL1, 3 mutations each in ABCA3 and NOTCH3, 2 mutations each in KCNK3 and HTR2B, 1 mutation in ENG, and 1 mutation in EIF2AK4. The mean age at diagnosis of PAH was 86.4 ± 55.1 months. Forty-eight patients (twenty-eight mutation carriers) underwent cardiac catheterization examinations, with acute vasodilator testing performed simultaneously. Results showed that mutation carriers demonstrated a higher pulmonary vascular resistance index (P = 0.037). Patients with gene mutations responded poorly to vasodilators (P = 0.001). The 1-, 2-, and 3-year survival rates of mutation noncarriers were 95.1%, 87.8%, and 82.5% respectively; while for mutation carriers, the proportions were 86.6% (P = 0.216), 63.8% (P = 0.021), and 52.2% (P = 0.010), respectively. Cardiac index was an independent predictor of death (P = 0.005; odds ratio [OR] 2.16, 95% confidence interval [CI] 1.258-3.704), as well as RAP (P = 0.01; OR 1.26, 95% CI 1.056-1.503).ConclusionsIn our cohort of Chinese pediatric patients, those with an identified gene mutation demonstrated worse clinical outcomes. Therefore, early gene screening for pediatric patients with idiopathic and heritable PAH is recommended, and more aggressive treatment for mutation carriers may be advisable. 相似文献
99.
Membrane trafficking processes are presumably vital for axonal regeneration after injury, but mechanistic understanding in this regard has been sparse. A recent loss-of-function screen had been carried out for factors important for axonal regeneration by cultured cortical neurons and the results suggested that the activity of a number of Rab GTPases might act to restrict axonal regeneration. A loss of Rab27b, in particular, is shown to enhance axonal regeneration in vitro, as well as in C. elegans and mouse central nervous system injury models in vivo. Possible mechanisms underlying this new finding, which has important academic and translational implication, are discussed. 相似文献
100.