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   246489篇
  免费   20811篇
  国内免费   5544篇
耳鼻咽喉   1920篇
儿科学   3539篇
妇产科学   3575篇
基础医学   26908篇
口腔科学   4382篇
临床医学   26780篇
内科学   29313篇
皮肤病学   2601篇
神经病学   20384篇
特种医学   27865篇
外国民族医学   19篇
外科学   19662篇
综合类   30925篇
现状与发展   22篇
一般理论   8篇
预防医学   15776篇
眼科学   3368篇
药学   27142篇
  106篇
中国医学   12798篇
肿瘤学   15751篇
  2024年   235篇
  2023年   3355篇
  2022年   4892篇
  2021年   9811篇
  2020年   9043篇
  2019年   8876篇
  2018年   8795篇
  2017年   9764篇
  2016年   10027篇
  2015年   9452篇
  2014年   12379篇
  2013年   15565篇
  2012年   13277篇
  2011年   15523篇
  2010年   10663篇
  2009年   10890篇
  2008年   12316篇
  2007年   13092篇
  2006年   12139篇
  2005年   11056篇
  2004年   9464篇
  2003年   8152篇
  2002年   6371篇
  2001年   5866篇
  2000年   4923篇
  1999年   4032篇
  1998年   3216篇
  1997年   3220篇
  1996年   2859篇
  1995年   2677篇
  1994年   2491篇
  1993年   2085篇
  1992年   1866篇
  1991年   1684篇
  1990年   1440篇
  1989年   1154篇
  1988年   1092篇
  1987年   998篇
  1986年   892篇
  1985年   1247篇
  1984年   994篇
  1983年   747篇
  1982年   766篇
  1981年   633篇
  1980年   614篇
  1979年   484篇
  1978年   302篇
  1977年   261篇
  1976年   247篇
  1975年   186篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
52.
Background and objective: Myocardial infarction (MI) is a common critical disease of the cardiovascular system. The process of MI is often accompanied by the excessive activation of cardiac sympathetic nerves, which leads to arrhythmia. Resiniferatoxin (RTX) is a transient receptor potential vanilloid 1 (TRPV1), involved in the cardiac sympathetic afferent reflex. However, whether RTX can reduce the occurrence of arrhythmia and exert a cardioprotective effect by inhibiting the sympathetic reflex during MI is still unknown. Methods: The left anterior descending artery of cardiac was clamped to construct a model of MI. RTX (50 μg/ml) was used by epicardial application in MI rats. Ventricular electrophysiologic properties were continuously monitored by a body surface ECG. Yrosine hydroxylase (TH) and growth associated protein 43 (GAP43) were detected by Immunofluorescence staining. Connexin43 and transforming growth factor beta receptor 1 (TGF-β1) were detected by western blot. Norepinephrine (NE) and BNP levels in blood and tissue were determined by ELISA. Cardiac function was assessed by echocardiography. Results: The ERP, APD90, QRS, QT and the Tend-Tpeak intervals in MI rats were all prolonged, but decreased after RTX treatment (n = 3, P<0.05). In contrast, the RR interval was shortened in the MI group, but prolonged in the MI+RTX group (n = 3, P<0.05). RTX treatment significantly reduced ventricular arrhythmias after MI. TH- and GAP43-positive nerve densities and TGF-β1, and cx-43 protein expression were up-regulated in the MI group compared to the sham group, and they were decreased in the MI+RTX group compared to the MI group (n = 3, P<0.05). RTX can decrease serum and tissue NE and BNP levels (n = 3, P<0.05). RTX pretreatment significantly decreased heart rate, HW/BW ratio and LVIDS, and increased LVEF andLVFS values (n = 3, P<0.05). Conclusion: RTX improved cardiac dysfunction, ventricular electrophysiologic properties, and sympathetic nerve remodeling in rats with MI by inhibiting the excessive cardiac sympathetic drive.  相似文献   
53.
54.
55.
56.
57.
58.
59.
目的 运用CT区分脾脏血管性病变与淋巴瘤。方法 回顾性分析20例经手术、穿刺病理学检查证实的脾脏病变的发病年龄、性别、脾脏指数、病变大小、数目、有无液化、钙化、强化幅度、强化方式等特征,并进行统计学分析。结果 20例脾脏病变中,11例血管性病变(6例海绵状血管瘤,3例窦岸细胞血管瘤,2例硬化性血管瘤样结节性转化),9例淋巴瘤;两组间发病年龄、病变大小、数目、有无液化、钙化等差异无统计学意义;两组间脾脏指数、动脉期强化幅度差异具有统计学意义(P<0.05)。5例海绵状血管瘤呈不均匀性强化,1例呈渐进性填充式强化,2例窦岸细胞血管瘤呈“雀斑征”,1例硬化性血管瘤样结节性转化呈“辐轮征”;9例淋巴瘤实质部分均呈均匀、轻中度强化。结论 脾脏血管性病变与淋巴瘤CT表现不同,CT有助于明确诊断。  相似文献   
60.
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