首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2898篇
  免费   391篇
  国内免费   284篇
耳鼻咽喉   15篇
儿科学   37篇
妇产科学   15篇
基础医学   334篇
口腔科学   33篇
临床医学   442篇
内科学   522篇
皮肤病学   51篇
神经病学   130篇
特种医学   118篇
外科学   296篇
综合类   440篇
现状与发展   2篇
预防医学   169篇
眼科学   163篇
药学   350篇
中国医学   238篇
肿瘤学   218篇
  2024年   10篇
  2023年   71篇
  2022年   104篇
  2021年   168篇
  2020年   141篇
  2019年   127篇
  2018年   125篇
  2017年   102篇
  2016年   129篇
  2015年   144篇
  2014年   178篇
  2013年   162篇
  2012年   219篇
  2011年   270篇
  2010年   163篇
  2009年   130篇
  2008年   191篇
  2007年   166篇
  2006年   205篇
  2005年   161篇
  2004年   86篇
  2003年   101篇
  2002年   62篇
  2001年   34篇
  2000年   47篇
  1999年   60篇
  1998年   36篇
  1997年   39篇
  1996年   21篇
  1995年   17篇
  1994年   15篇
  1993年   13篇
  1992年   18篇
  1991年   11篇
  1990年   13篇
  1989年   7篇
  1988年   11篇
  1987年   2篇
  1986年   4篇
  1985年   3篇
  1984年   1篇
  1982年   1篇
  1977年   1篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1971年   1篇
排序方式: 共有3573条查询结果,搜索用时 15 毫秒
1.
Despite a decline in the incidence of squamous cell carcinomas (SCCs) over the past 20 years, their survival rate has remained nearly the same, indicating that treatment options have not improved relative to other cancer types. Immunotherapies have a high potential for a sustained effect in SCC patients, but their response rate is low. Here, we review the suppressive role of transforming growth factor-beta (TGFβ) on the antitumor immune response in SCC and present its potential as a therapeutic target in combination with the current range of immunotherapies available for SCC patients. We conclude that SCCs are an optimal cancer type to study the effectiveness of TGFβ inhibition due to the prevalence of dysregulated TGFβ signaling in them.  相似文献   
2.
BackgroundThe relationship between body mass index (BMI) and in-hospital mortality risk among patients with acute myocardial infarction (AMI) remains controversial.Methods and ResultsWe included 35,964 patients diagnosed with AMI in China Acute Myocardial Infarction registry between January 2013 and December 2016. Patients were categorized into 4 groups according to BMI level: BMI <18.5, 18.5–24.9, 25–30, and ≥30 kg/m2 for underweight, normal, overweight, and obese groups, respectively. Clinical data were extracted for each patient, and multivariable logistic regression analysis was used to examine the association between BMI level and in-hospital mortality. Compared with normal-weight patients, obese patients were younger, more often current smokers, and more likely to have hypertension, hyperlipidemia, and diabetes. Multivariable regression analysis results demonstrated that compared with normal group, underweight group had significantly higher in-hospital mortality (odds ratio [OR]: 1.34; 95% confidence interval [CI]: 1.06–1.69; p = 0.016), while overweight group (OR: 0.86; 95% CI: 0.77–0.97; p = 0.011) and obese group (OR: 0.65; 95% CI: 0.46–0.91; p = 0.013) had lower mortality. All subgroups showed a trend toward lower in-hospital mortality risk as BMI increased.ConclusionsOur study provided robust evidence supporting “obesity paradox” in a contemporary large-scale cohort of patients with AMI and demonstrated that increased BMI was independently associated with lower in-hospital mortality.  相似文献   
3.
Celiac disease (CD) is an autoimmune intestinal disease caused by the intake of gluten-containing cereals and their products by individuals with genetic susceptibility genes. Vitiligo is a commonly acquired depigmentation of the skin; its clinical manifestation are skin patches caused by localized or generalized melanin deficiency. Both diseases have similar global incidence rates (approximately 1%) and are associated to similar diseases, including autoimmune bullous disease, inflammatory bowel disease, autoimmune thyroiditis, autoimmune gastritis, and type 1 diabetes. The relationship between CD and vitiligo has been reported in several studies, but their conclusions are inconsistent. Further, it has also been reported that a gluten-free diet (GFD) can improve the symptoms of immune-related skin diseases such as vitiligo. In this mini-review, we summarize and review the literature on the relationship between CD and vitiligo, assess the therapeutic significance of GFD for patients with vitiligo, and explore their possible physiopathology. We are hopeful that the information summarized here will assist physicians who treat patients with CD or vitiligo, thereby improving the prognosis.  相似文献   
4.
5.
目的 分析重症患者营养支持期间发生再喂养综合征的危险因素,为早期识别及预防再喂养综合征提供参考。方法 检索中国知网、万方数据库、中华医学期刊全文数据库、中国生物医学文献数据库、维普网、PubMed、Embase、Cochrane Library、Elsevier关于重症患者再喂养综合征危险因素的文献,检索时间为各数据库建库至2021年12月,采用RevMan5.3进行Meta分析。结果 纳入13篇文献,包括2 519例患者,其中病例组793例,对照组1 726例;Meta分析合并效应值显示年龄(WMD=4.69)、APACHEⅡ评分(WMD=2.50)、BMI(WMD=-0.94)、白蛋白水平(OR=4.61)、前白蛋白水平(WMD=-53.46)、基线血镁水平(WMD=-0.05)、基线血钾水平(WMD=0.18)、基线血磷水平(WMD=-0.07)是重症患者发生再喂养综合征的危险因素(P<0.05,P<0.01)。结论 基于现有证据,重症患者再喂养综合征的危险因素包括年龄、APACHEⅡ评分、营养状况及电解质水平,医护人员需密切关注重症患者营养支持期间能量、蛋白质及电解...  相似文献   
6.
Apelin-13 is a novel endogenous ligand for an angiotensin-like orphan G-protein coupled receptor, and it may be neuroprotective against cerebral ischemia injury. However, the precise mechanisms of the effects of apelin-13 remain to be elucidated. To investigate the effects of apelin-13 on apoptosis and autophagy in models of cerebral ischemia/reperfusion injury, a rat model was established by middle cerebral artery occlusion. Apelin-13(50 μg/kg) was injected into the right ventricle as a treatment. In addition, an SH-SY5 Y cell model was established by oxygen-glucose deprivation/reperfusion, with cells first cultured in sugar-free medium with 95% N2 and 5% CO2 for 4 hours and then cultured in a normal environment with sugar-containing medium for 5 hours. This SH-SY5 Y cell model was treated with 10–7 M apelin-13 for 5 hours. Results showed that apelin-13 protected against cerebral ischemia/reperfusion injury. Apelin-13 treatment alleviated neuronal apoptosis by increasing the ratio of Bcl-2/Bax and significantly decreasing cleaved caspase-3 expression. In addition, apelin-13 significantly inhibited excessive autophagy by regulating the expression of LC3 B, p62, and Beclin1. Furthermore, the expression of Bcl-2 and the phosphatidylinositol-3-kinase(PI3 K)/Akt/mammalian target of rapamycin(mTOR) pathway was markedly increased. Both LY294002(20 μM) and rapamycin(500 nM), which are inhibitors of the PI3 K/Akt/mTOR pathway, significantly attenuated the inhibition of autophagy and apoptosis caused by apelin-13. In conclusion, the findings of the present study suggest that Bcl-2 upregulation and mTOR signaling pathway activation lead to the inhibition of apoptosis and excessive autophagy. These effects are involved in apelin-13-induced neuroprotection against cerebral ischemia/reperfusion injury, both in vivo and in vitro. The study was approved by the Animal Ethical and Welfare Committee of Jining Medical University, China(approval No. 2018-JS-001) in February 2018.  相似文献   
7.
8.
目的探讨在关节镜下经髌腱入路,利用空心拉力螺钉复位固定胫骨髁间嵴撕脱骨折(TEFx)的安全性和有效性。方法选取2014年1月-2015年12月23例TEFx的患者,均在关节镜下经髌腱入路,用空心拉力螺钉复位固定。术前Meyers-McKeever分型:Ⅱ型8例,Ⅲ型10例,Ⅳ型5例;男17例,女6例;年龄16~53岁,平均27.8岁。术前前抽屉试验、Lachman试验均阳性。比较术前术后的视觉模拟评分(VAS)、Lysholm、Tegner和国际膝关节文献委员会(IKDC)评分评价患侧膝关节功能。结果 23例患者均得到随访,随访时间30~40个月,平均36个月。术后即刻X线片示TEFx均复位良好,术后3个月骨折均愈合。无1例感染、关节僵硬、伸直受限、复位丢失及神经血管损伤等并发症。最终随访患侧膝关节活动度均恢复正常,前抽屉试验、Lachman试验均阴性。VAS评分术前(4.8±1.2)分,最终随访为(1.2±0.8)分,术前术后比较,差异有统计学意义(t=18.72,P=0.003);Lysholm评分术前为(50.8±6.2)分,最终随访为(90.8±5.4)分,术前术后比较,差异有统计学意义(t=-42.64,P=0.000);Tegner评分术前为(4.0±1.0)分,最终随访为(5.1±1.2)分,术前术后比较,差异有统计学意义(t=-16.82,P=0.005);IKDC主观评分术前为(52.5±7.4)分,最终随访为(91.5±5.7)分,术前术后比较,差异有统计学意义(t=-40.58,P=0.000)。结论膝关节镜下经髌腱入路空心拉力螺钉内固定治疗TEFx具有微创、操作简捷、固定可靠和恢复快的优点。  相似文献   
9.
目的:探讨RNA结合蛋白QKI-5在肾癌中的生物学功能。方法:应用以慢病毒为载体的过表达技术观察过表达QKI-5对肾癌细胞增殖作用的影响及对细胞周期的影响。结果:过表达QKI-5能够抑制肾癌细胞株786-O和A-498细胞的增殖能力、克隆形成能力;流式细胞术结果显示:过表达QKI-5使786-O和A-498细胞产生G1期阻滞,而这种阻滞与周期相关蛋白Cyclin D1表达降低及p21、p27表达增高有关。结论:QKI-5在肾癌中发挥着抑癌基因的功能,可以抑制肾癌细胞增殖,并使细胞周期阻滞在G1期。  相似文献   
10.
正胆囊癌是胆道系统最常见的恶性肿瘤之一,其发病率居消化系统肿瘤第6位~([1])。胆囊癌症状隐匿,早期诊断率低,相当比例患者初次诊断时已处于中晚期;同时,胆囊癌恶性程度高,侵袭性强,易发生脉管及组织浸润;因此,胆囊癌患者总体预后极差,中晚期胆囊癌患者5年总体生存率仅5%~10%~([2-3])。目前,根治性手术切除依然是胆囊癌唯一有效的治疗手段。尽管腹腔镜根治性手术在胃癌、肝癌及结直肠癌等腹腔肿瘤中已广泛应用~([4-6]),其在胆囊癌中的应用依然有限  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号