全文获取类型
收费全文 | 265616篇 |
免费 | 61442篇 |
国内免费 | 12696篇 |
专业分类
耳鼻咽喉 | 2934篇 |
儿科学 | 6716篇 |
妇产科学 | 2528篇 |
基础医学 | 41009篇 |
口腔科学 | 8533篇 |
临床医学 | 35737篇 |
内科学 | 47976篇 |
皮肤病学 | 9277篇 |
神经病学 | 21188篇 |
特种医学 | 8925篇 |
外国民族医学 | 74篇 |
外科学 | 31103篇 |
综合类 | 36210篇 |
现状与发展 | 41篇 |
一般理论 | 35篇 |
预防医学 | 19180篇 |
眼科学 | 5907篇 |
药学 | 28092篇 |
185篇 | |
中国医学 | 12676篇 |
肿瘤学 | 21428篇 |
出版年
2024年 | 833篇 |
2023年 | 3135篇 |
2022年 | 8084篇 |
2021年 | 11207篇 |
2020年 | 12344篇 |
2019年 | 16401篇 |
2018年 | 16117篇 |
2017年 | 17109篇 |
2016年 | 17351篇 |
2015年 | 20043篇 |
2014年 | 21964篇 |
2013年 | 22230篇 |
2012年 | 18661篇 |
2011年 | 19333篇 |
2010年 | 19620篇 |
2009年 | 14016篇 |
2008年 | 12502篇 |
2007年 | 11484篇 |
2006年 | 10710篇 |
2005年 | 9422篇 |
2004年 | 7702篇 |
2003年 | 7794篇 |
2002年 | 6886篇 |
2001年 | 5893篇 |
2000年 | 4826篇 |
1999年 | 3806篇 |
1998年 | 2203篇 |
1997年 | 2343篇 |
1996年 | 1627篇 |
1995年 | 1574篇 |
1994年 | 1402篇 |
1993年 | 941篇 |
1992年 | 1175篇 |
1991年 | 1098篇 |
1990年 | 963篇 |
1989年 | 859篇 |
1988年 | 752篇 |
1987年 | 661篇 |
1986年 | 618篇 |
1985年 | 475篇 |
1984年 | 404篇 |
1983年 | 327篇 |
1982年 | 288篇 |
1981年 | 239篇 |
1980年 | 205篇 |
1979年 | 212篇 |
1978年 | 193篇 |
1977年 | 211篇 |
1976年 | 191篇 |
1974年 | 156篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
目的 系统评价翻转课堂教学模式在物理治疗学教学中的应用效果。方法 计算机检索CENTRAL、MEDLINE、EMBASE、CINAHL Plus、Academic Search Premier、Teacher Reference Center、ERIC以及Education Research,纳入翻转课堂教学模式应用于物理治疗学教学的原始研究。检索时限为建库至2021年6月。由2名研究人员独立完成文献筛选、数据提取、质量评价,对翻转课堂教学模式对比传统教学模式在物理治疗学教学中的效果进行综述。结果与结论 共检索文献1 307篇,最终纳入7篇,包括至少770名学生。发表时间集中在2013年至2019年,研究对象为物理治疗学专业学生,主要结局指标为考试成绩。翻转课堂教学模式总体说来可提高学生的笔试成绩,增强高阶思维能力,得到了学生和教师的积极评价。 相似文献
2.
3.
目的探究老年胃癌患者术前血清白细胞介素6 (IL-6)、胃蛋白酶原(PG)Ⅰ、Ⅱ及PG-Ⅰ/Ⅱ比值在患者预后评估中的意义。方法选择2016年1月—2017年1月南通大学附属海安医院收治的101例外科手术治疗的老年胃癌患者为研究对象。收集患者的临床病理资料,检测血清IL-6和PG-Ⅰ/Ⅱ水平。以全因死亡为随访终点,使用Kaplan-Meier曲线明确患者预后与各指标间的关系。结果受试者工作特征曲线提示,IL-6、PG-Ⅰ和PG-Ⅰ/Ⅱ比值在最佳切割值为10.23pg/mL、30.65μg/L和2.44时,可评估患者的预后,而PG-Ⅱ则无法评估患者的预后。与IL-6≤10.23pg/mL组相比,IL-6> 10.23pg/mL组的肿瘤细胞分化更差、TNM分期Ⅲ期比例明显升高。Kaplan-Meier曲线结果表明,IL-6> 10.23pg/mL组的中位生存期显著短于IL-6≤10.23pg/mL组(28个月vs47个月,P<0.001);PG-Ⅰ≤30.65μg/L组的中位生存期显著短于PG-Ⅰ>30.65μg/L组(34个月vs49个月,P=0.008);PG-Ⅰ/Ⅱ≤2.44组的中位生存期显著短于PG-Ⅰ/Ⅱ> 2.44组(29个月vs56个月,P=0.02)。多因素Cox回归分析表明,肿瘤分化程度、TNM分期、IL-6及PG-Ⅰ/Ⅱ比值是影响患者生存率的独立危险因素。结论术前检测IL-6及PG-Ⅰ/Ⅱ比值有助于评估老年胃癌患者的预后。 相似文献
4.
Noninvasive imaging of cardiac fibrosis is important for early diagnosis and intervention in chronic heart diseases. Here, we investigated whether noninvasive, contrast agent-free MRI T2-mapping can quantify myocardial fibrosis in preclinical models of aging and pressure overload. Myocardial fibrosis and remodeling were analyzed in two animal models: (i) aging (15-month-old male CF-1 mice vs. young 6- to 8-week-old mice), and (ii) pressure overload (PO; by transverse aortic constriction in 4- to 5-month-old male C57BL/6 mice vs. sham-operated for 14 days). In vivo T2-mapping was performed by acquiring data during the isovolumic and early diastolic phases, with a modified respiratory and ECG-triggered multiecho TurboRARE sequence on a 7-T MRI. Cine MRI provided cardiac morphology and function. A quantitative segmentation method was developed to analyze the in vivo T2-maps of hearts at midventricle, apex, and basal regions. The cardiac fibrosis area was analyzed ex vivo by picro sirius red (PSR) staining. Both aged and pressure-overloaded hearts developed significant myocardial contractile dysfunction, cardiac hypertrophy, and interstitial fibrosis. The aged mice had two phenotypes, fibrotic and mild-fibrotic. Notably, the aged fibrotic subgroup and the PO mice showed a marked decrease in T2 relaxation times (25.3 ± 0.6 in aged vs. 29.9 ± 0.7 ms in young mice, p = 0.002; and 24.3 ± 1.7 in PO vs. 28.7 ± 0.7 ms in shams, p = 0.05). However, no significant difference in T2 was detected between the aged mild-fibrotic subgroup and the young mice. Accordingly, an inverse correlation between myocardial fibrosis percentage (FP) and T2 relaxation time was derived (R2 = 0.98): T2 (ms) = 30.45 – 1.05 × FP. Thus, these results demonstrate a statistical agreement between T2-map–quantified fibrosis and PSR staining in two different clinically relevant animal models. In conclusion, T2-mapping MRI is a promising noninvasive contrast agent-free quantitative technique to characterize myocardial fibrosis. 相似文献
5.
Mette Nissen Tiina‐Mari Ikheimo Jukka Huttunen Ville Leinonen Henna‐Kaisa Jyrkknen Mikael von und zu Fraunberg 《Neuromodulation》2021,24(1):102-111
ObjectiveSpinal cord stimulation (SCS) is an effective treatment in failed back surgery syndrome (FBSS). We studied the effect of preimplantation opioid use on SCS outcome and the effect of SCS on opioid use during a two-year follow-up period.Materials and methodsThe study cohort included 211 consecutive FBSS patients who underwent an SCS trial from January 1997 to March 2014. Participants were divided into groups, which were as follows: 1) SCS trial only (n = 47), 2) successful SCS (implanted and in use throughout the two-year follow-up period, n = 131), and 3) unsuccessful SCS (implanted but later explanted or revised due to inadequate pain relief, n = 29). Patients who underwent explantation for other reasons (n = 4) were excluded. Opioid purchase data from January 1995 to March 2016 were retrieved from national registries.ResultsHigher preimplantation opioid doses associated with unsuccessful SCS (ROC: AUC = 0.66, p = 0.009), with 35 morphine milligram equivalents (MME)/day as the optimal cutoff value. All opioids were discontinued in 23% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.004). Strong opioids were discontinued in 39% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.04). Mean opioid dose escalated from 18 ± 4 MME/day to 36 ± 6 MME/day with successful SCS and from 22 ± 8 MME/day to 82 ± 21 MME/day with unsuccessful SCS (p < 0.001).ConclusionsHigher preimplantation opioid doses were associated with SCS failure, suggesting the need for opioid tapering before implantation. With continuous SCS therapy and no explantation or revision due to inadequate pain relief, 39% of FBSS patients discontinued strong opioids, and 23% discontinued all opioids. This indicates that SCS should be considered before detrimental dose escalation. 相似文献
6.
7.
Qian Zhang Larry D. Mesner Gina M. Calabrese Naomi Dirckx Zhu Li Angela Verardo Qian Yang Robert J. Tower Marie-Claude Faugere Charles R. Farber Thomas L. Clemens 《The Journal of clinical investigation》2021,131(7)
Bone mineral density (BMD) is a highly heritable predictor of osteoporotic fracture. GWAS have identified hundreds of loci influencing BMD, but few have been functionally analyzed. In this study, we show that SNPs within a BMD locus on chromosome 14q32.32 alter splicing and expression of PAR-1a/microtubule affinity regulating kinase 3 (MARK3), a conserved serine/threonine kinase known to regulate bioenergetics, cell division, and polarity. Mice lacking Mark3 either globally or selectively in osteoblasts have increased bone mass at maturity. RNA profiling from Mark3-deficient osteoblasts suggested changes in the expression of components of the Notch signaling pathway. Mark3-deficient osteoblasts exhibited greater matrix mineralization compared with controls that was accompanied by reduced Jag1/Hes1 expression and diminished downstream JNK signaling. Overexpression of Jag1 in Mark3-deficient osteoblasts both in vitro and in vivo normalized mineralization capacity and bone mass, respectively. Together, these findings reveal a mechanism whereby genetically regulated alterations in Mark3 expression perturb cell signaling in osteoblasts to influence bone mass. 相似文献
8.
9.
Near-infrared diffuse correlation spectroscopy/tomography (DCS/DCT) has recently emerged as a noninvasive measurement/imaging technology for tissue blood flow. In DCT studies, the high-dense collection of light temporal autocorrelation curves (g2(τ)) via fiber array are critical for image reconstruction of blood flow. Previously, the camera-based fiber array limits the field of view (FOV), precluding its applications on large-size human tissues. The line-shape fiber probe based on lens combination, which is predominantly used in current DCT studies, requires rotated-scanning over the surface of target tissue, substantially prolonging the measurement time and increasing the system instability. In this study, we design a noncontact optical probe for DCT based on collimating micro-lens fiber array, termed as FA-nc-DCT system. For each source/detector fiber, a single optical path was collimated by coupling with one micro-lens in the fiber array that is integrated in a square-shape base. Additionally, an 8×8 optical switch is used to share the hardware laser and detectors without spatial scanning. The FA-nc approach for the precise collection of g2(τ) curves was validated through a speed-varied phantom experiment and the human experiments of cuff occlusion, from which the expected value of the blood flow index (BFI) was obtained. Furthermore, the flow anomaly in the phantom and the ischemic muscle in human were accurately reconstructed from the FA-nc-DCT system, which is combined with the imaging framework based on the Nth-order linear algorithm that we recently created. Those outcomes demonstrated the great potential of FA-nc-DCT technology for fast and robust imaging of various diseases such as human breast cancers. 相似文献
10.
Qiangsheng He Chongfei Huang Xiwen Qin Yuanyuan Yu Di Tang Junjie Huang Zi Chong Kuo Yuyao Ling Deli Mao Bin Xia Wenjing Li Kuiqing Lu Man Yang Yulong He Wenbo Meng Jinqiu Yuan Yihang Pan 《International journal of cancer. Journal international du cancer》2023,153(5):942-949
Recent epidemiological studies suggested that proton pump inhibitor (PPI) use was associated with an increased risk of biliary tract cancer (BTC), however, confounders were not adequately controlled. Our study aimed to evaluate PPI use and subsequent risk of BTC and its subtypes in three well-established cohorts. We conducted a pooled analysis of the subjects free of cancers in UK Biobank (n = 463 643), Nurses' Health Study (NHS, n = 80 235) and NHS II (n = 95 869). Propensity score weighted Cox models were used to estimate marginal HRs of PPIs use on BTC risk, accounting for potential confounders. We documented 284 BTC cases in UK Biobank (median follow-up: 7.6 years), and 91 cases in NHS and NHS II cohorts (median follow-up: 15.8 years). In UK biobank, PPI users had a 96% higher risk of BTC compared to nonusers in crude model (HR 1.96, 95% CI 1.44-2.66), but the effect was attenuated to null after adjusting for potential confounders (HR 0.95, 95% CI 0.60-1.49). PPI use was not associated with risk of BTC in the pooled analysis of three cohorts (HR 0.93, 95% CI 0.60-1.43). We also observed no associations between PPI use with risk of intrahepatic (HR 1.00, 95% CI 0.49-2.04), extrahepatic bile duct (HR 1.09, 95% CI 0.52-2.27) and gallbladder cancers (HR 0.66, 95% CI 0.26-1.66) in UK Biobank. In summary, regular use of PPIs was not associated with the risk of BTC and its subtypes. 相似文献