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   34356篇
  免费   2558篇
  国内免费   1551篇
耳鼻咽喉   15篇
儿科学   288篇
妇产科学   37篇
基础医学   2047篇
口腔科学   41篇
临床医学   2997篇
内科学   7094篇
皮肤病学   33篇
神经病学   676篇
特种医学   708篇
外国民族医学   42篇
外科学   8152篇
综合类   6894篇
现状与发展   1篇
预防医学   828篇
眼科学   28篇
药学   2294篇
  27篇
中国医学   1332篇
肿瘤学   4931篇
  2024年   44篇
  2023年   471篇
  2022年   677篇
  2021年   1353篇
  2020年   1168篇
  2019年   1030篇
  2018年   996篇
  2017年   1036篇
  2016年   1137篇
  2015年   1209篇
  2014年   2111篇
  2013年   2279篇
  2012年   1824篇
  2011年   2073篇
  2010年   1634篇
  2009年   1723篇
  2008年   1736篇
  2007年   1922篇
  2006年   1650篇
  2005年   1580篇
  2004年   1291篇
  2003年   1094篇
  2002年   947篇
  2001年   971篇
  2000年   861篇
  1999年   697篇
  1998年   628篇
  1997年   564篇
  1996年   488篇
  1995年   492篇
  1994年   421篇
  1993年   332篇
  1992年   292篇
  1991年   279篇
  1990年   232篇
  1989年   200篇
  1988年   184篇
  1987年   142篇
  1986年   94篇
  1985年   95篇
  1984年   102篇
  1983年   57篇
  1982年   79篇
  1981年   48篇
  1980年   55篇
  1979年   42篇
  1978年   33篇
  1977年   29篇
  1976年   20篇
  1975年   13篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
41.
42.
Epstein–Barr virus (EBV)-associated gastric carcinomas (EBVaGCs) may account for 8–9% of all gastric cancer (GC) patients. All previous reports on EBVaGC were retrospective. Prospective study is warranted to evaluate the exact role of EBV status in predicting the prognosis of GC. It is of special interest to figure out whether dynamic detection of plasma EBV-DNA load could be a feasible biomarker for the monitor of EBVaGC. From October 2014 to September 2017, we consecutively collected GC patients (n = 2,760) from Sun Yat-sen University Cancer Center for EBER examination. We detected EBV-DNA load in plasma and tissue samples of EBVaGC patients at baseline. Subsequently, plasma EBV-DNA load was dynamically monitored in EBVaGC patients. The overall prevalence of EBVaGC is 5.1% (140/2,760). The incidence rate of EBVaGC decreased with advanced AJCC 7th TNM stage (p < 0.001), with the corresponding percentages of 9.3, 9.9, 6.7 and 1.4% for Stage I, II, III and IV patients. EBVaGC patients were predominately young males with better histologic differentiation and earlier TNM stage than EBV-negative GC (EBVnGC) patients. EBVaGC patients were confirmed to had a favorable 3-year survival rate (EBVaGC vs. EBVnGC: 76.8% vs. 58.2%, p = 0.0001). Though only 52.1% (73/140) EBVaGC patients gained detectable EBV-DNA and 43.6% (61/140) reached a positive cutoff of 100 copies/ml, we found the plasma EBV-DNA load in EBVaGC decreased when patients got response, while it increased when disease progressed. Our results suggested that plasma EBV-DNA is a good marker in predicting recurrence and chemotherapy response for EBVaGC patients.  相似文献   
43.
内镜治疗技术的发展进一步推动了早期胃癌的微创治疗。然而,随之而来的问题是,部分接受内镜治疗的病人会出现非治愈性切除。早期胃癌内镜治疗后非治愈性病人的后续处理原则值得进一步关注。结合欧洲肿瘤内科学会(ESMO)、美国国家综合癌症网络(NCCN)及日本胃癌学会等国际指南及相关临床研究并回顾分析单中心数据后可得出结论,eCura-C的病人具有相对较高的癌残留风险,在与病人充分沟通后可考虑追加手术,但仍有较高的术后病理学无癌残留的风险。术式选择和切除范围可参考早期胃癌相关规定。如何准确预测非治愈性病人的淋巴结转移仍是未来的重点。前哨淋巴结活检及腹腔镜内镜联合手术是未来的发展方向。  相似文献   
44.
45.
目前化疗仍为晚期胃癌的标准治疗手段,而多数患者诊断时已接近晚期。近年新兴的免疫治疗手段程序性死亡蛋白-1(PD-1,programmed death l)抗体,通过阻断肿瘤细胞逃避自身免疫机制,重新激活自身免疫对肿瘤的杀伤作用,从而达到肿瘤的治疗作用。针对晚期胃癌的PD-1抗体治疗的临床研究已在国内外开展,大部分均有较好效果。本文对近年免疫治疗中的PD-1抗体在晚期胃癌的重要临床研究进展进行介绍。  相似文献   
46.
目的探讨扬州地区肝硬化食管静脉曲张初次出血患者诊治特点。方法回顾性分析2010年1月-2013年12月苏北人民医院消化内科收治的80例肝硬化食管静脉曲张初次出血患者病例资料。计数资料用率或构成比表示,率的比较采用χ2检验。结果由乙型肝炎导致肝硬化所引起的食管静脉曲张破裂出血所占比例最大;三腔二囊管临床运用可最大限度地挽救患者生命,为后期治疗提供时间;基础治疗包括止血、输血、抑酸、补液等,后期以硬化剂、套扎、硬化剂+套扎、手术、经颈静脉肝内门体分流术(TIPS)为主,但套扎运用最为广泛;患者出血初期各项指标变化有利于指导临床治疗,对患者预后具有良好的评估作用。结论扬州地区肝硬化引起的食管静脉曲张破裂出血病因呈现复杂交叉性,治疗方法仍需进一步完善,以达到个体化治疗水平;及时正确的救治,对提高临床疗效、降低病死率有重要意义;早期的健康体检,对疾病诊治起关键性的作用。  相似文献   
47.
ObjectivesSevere acute kidney injury (AKI) is a known risk factor for infection and mortality. However, whether stage 1 AKI is a risk factor for infection has not been evaluated in adults. We hypothesized that stage 1 AKI following cardiac surgery would independently associate with infection and mortality.MethodsIn this retrospective propensity score–matched study, we evaluated 1620 adult patients who underwent nonemergent cardiac surgery at the University of Colorado Hospital from 2011 to 2017. Patients who developed stage 1 AKI by Kidney Disease Improving Global Outcomes creatinine criteria within 72 hours of surgery were matched to patients who did not develop AKI. The primary outcome was an infection, defined as a new surgical-site infection, positive blood or urine culture, or development of pneumonia. Secondary outcomes included in-hospital mortality, stroke, and intensive care unit (ICU) and hospital length of stay (LOS).ResultsStage 1 AKI occurred in 293 patients (18.3%). Infection occurred in 20.9% of patients with stage 1 AKI compared with 8.1% in the no-AKI group (P < .001). In propensity-score matched analysis, stage 1 AKI independently associated with increased infection (odds ratio [OR]; 2.24, 95% confidence interval [CI], 1.37-3.17), ICU LOS (OR, 2.38; 95% CI, 1.71–3.31), and hospital LOS (OR, 1.30; 95% CI, 1.17-1.45).ConclusionsStage 1 AKI is independently associated with postoperative infection, ICU LOS, and hospital LOS. Treatment strategies focused on prevention, early recognition, and optimal medical management of AKI may decrease significant postoperative morbidity.  相似文献   
48.

Background

Chronic limb-threatening ischemia (CLTI), defined as ischemic rest pain or tissue loss secondary to arterial insufficiency, is caused by multilevel arterial disease with frequent, severe infrageniculate disease. The rise in CLTI is in part the result of increasing worldwide prevalence of diabetes, renal insufficiency, and advanced aging of the population. The aim of this study was to compare a bypass-first with an endovascular-first revascularization strategy in patients with CLTI due to infrageniculate arterial disease.

Methods

We reviewed the American College of Surgeons National Surgical Quality Improvement Program targeted lower extremity revascularization database from 2012 to 2015 to identify patients with CLTI and isolated infrageniculate arterial disease who underwent primary infrageniculate bypass or endovascular intervention. We excluded patients with a history of ipsilateral revascularization and proximal interventions. The end points were major adverse limb event (MALE), major adverse cardiovascular event (MACE), amputation at 30 days, reintervention, patency, and mortality. Multivariable logistic regression was used to determine the association of a bypass-first or an endovascular-first intervention with outcomes.

Results

There were 1355 CLTI patients undergoing first-time revascularization to the infrageniculate arteries (821 endovascular-first revascularizations and 534 bypass-first revascularizations) identified. There was no significant difference in adjusted rate of 30-day MALE in the bypass-first vs endovascular-first revascularization cohort (9% vs 11.2%; odds ratio [OR], 0.73; 95% confidence interval [CI], 0.50-1.08). However, the incidence of transtibial or proximal amputation was lower in the bypass-first cohort (4.3% vs 7.4%; OR, 0.60; CI, 0.36-0.98). Patients with bypass-first revascularization had higher wound complication rates (9.7% vs 3.7%; OR, 2.75; CI, 1.71-4.42) compared with patients in the endovascular-first cohort. Compared with the endovascular-first cohort, the incidence of 30-day MACE was significantly higher in bypass-first patients (6.9% vs 2.6%; adjusted OR, 3.88; CI, 2.18-6.88), and 30-day mortality rates were 3.23% vs 1.8% (adjusted OR, 2.77; CI, 1.26-6.11). There was no difference in 30-day untreated loss of patency, reintervention of treated arterial segment, readmissions, and reoperations between the two cohorts. In subgroup analysis after exclusion of dialysis patients, there was also no significant difference in MALE or amputation between the bypass-first and endovascular-first cohorts.

Conclusions

CLTI patients with isolated infrageniculate arterial disease treated by a bypass-first approach have a significantly lower 30-day amputation. However, this benefit was not observed when dialysis patients were excluded. The bypass-first cohort had a higher incidence of MACE compared with an endovascular-first strategy. These results reaffirm the need for randomized controlled trials, such as the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL-2) trial and Best Endovascular vs Best Surgical Therapy in Patients with Critical Limb Ischemia (BEST-CLI), to provide level 1 evidence for the role of endovascular-first vs bypass-first revascularization strategies in the treatment of this population of challenging patients.  相似文献   
49.
50.
BackgroundDetails of perioperative outcomes and survival after gastric cancer surgery in prior transplant recipients have received minimal research attention.MethodsWe performed an observational cohort study using the database of 20,147 gastric cancer patients who underwent gastrectomy at a single gastric cancer center in Korea. Forty-one solid organ recipients [kidney (n = 35), liver (n = 5), or heart (n = 1)] were matched with 205 controls using propensity score matching.ResultsOperation time, blood loss, and postoperative pain were similar between groups. Short-term complication rates were similar between transplantation and control groups (22.0% vs. 20.1%, P = 0.777). Transplantation group patients with stage 1 gastric cancer experienced no recurrence, while those with stage 2/3 cancer had significantly higher recurrence risk compared to the controls (P = 0.049). For patients with stage 1 cancer, the transplantation group had a significantly higher rate of non-gastric cancer-related deaths compared to the controls (19.2% vs. 1.4%, P = 0.001). For those with stage 2/3 cancer, significantly lower proportion of the transplantation group received adjuvant chemotherapy compared to the control group (26.7% vs. 80.3%, P < 0.001). The transplantation group had a higher (albeit not statistically significant) rate of gastric cancer-related deaths compared to the controls (40.0% vs. 18.0%, P = 0.087).ConclusionTransplant recipients and non-transplant recipients exhibited similar perioperative and short-term outcomes after gastric cancer surgery. From long-term outcome analyses, we suggest active surveillance for non-gastric cancer-related deaths in patients with early gastric cancer, as well as strict oncologic care in patients with advanced cancer, as effective strategies for transplant recipients.  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