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   238449篇
  免费   17277篇
  国内免费   5225篇
耳鼻咽喉   3498篇
儿科学   6033篇
妇产科学   4229篇
基础医学   25501篇
口腔科学   7380篇
临床医学   21001篇
内科学   46006篇
皮肤病学   6100篇
神经病学   14712篇
特种医学   7090篇
外国民族医学   2篇
外科学   26082篇
综合类   22455篇
现状与发展   13篇
一般理论   43篇
预防医学   26653篇
眼科学   4337篇
药学   19762篇
  116篇
中国医学   9274篇
肿瘤学   10664篇
  2024年   545篇
  2023年   2395篇
  2022年   4403篇
  2021年   7621篇
  2020年   5267篇
  2019年   5592篇
  2018年   7790篇
  2017年   6072篇
  2016年   5409篇
  2015年   7355篇
  2014年   9434篇
  2013年   12891篇
  2012年   18215篇
  2011年   19373篇
  2010年   13333篇
  2009年   11335篇
  2008年   15200篇
  2007年   15447篇
  2006年   14034篇
  2005年   12835篇
  2004年   10673篇
  2003年   9585篇
  2002年   8593篇
  2001年   6154篇
  2000年   6153篇
  1999年   4454篇
  1998年   1227篇
  1997年   1050篇
  1996年   933篇
  1995年   792篇
  1994年   631篇
  1993年   550篇
  1992年   1645篇
  1991年   1364篇
  1990年   1241篇
  1989年   1062篇
  1988年   924篇
  1987年   841篇
  1986年   852篇
  1985年   735篇
  1984年   531篇
  1983年   464篇
  1979年   450篇
  1975年   314篇
  1974年   387篇
  1973年   389篇
  1972年   342篇
  1971年   374篇
  1970年   328篇
  1969年   350篇
排序方式: 共有10000条查询结果,搜索用时 20 毫秒
51.
目的 收集藿香正气汤的主要活性成分,通过分子对接及网络药理学探讨其防控新型冠状病毒肺炎(COVID-19)的有效成分及治疗机制。方法 通过基于配体-蛋白质相互作用的计算方法,以瑞德西韦为对照,探索藿香正气汤潜在治疗COVID-19的成分,并选出对接较好成分进行药理学机制预测,初探其药理学机制。结果 本研究筛选出5种与新冠病毒3CLpro结合能力强于瑞德西韦的小分子成分。网络药理学初步预测抗病毒途径可能是通过PI3K-Akt 信号通路影响病毒复制。结论 成分C1-C5与3CLpro结合良好,推测其可能是潜在的3CLpro的抑制剂,为抗病毒天然药物的开发提供了理论依据。  相似文献   
52.
53.
54.

Objectives

To determine the incidence of incisional hernia (IH) in the extraction incision (EI) in colorectal resection for cancer. To analyze whether the location of the incision has any relationship with the incidence of hernias and whether mesh could be useful for prevention in high-risk patients.

Methods

Retrospective review of the colon and rectal surgery database from January 2015 to December 2016. Data were classified into 2 groups, transverse (TI) and midline incision (MI), and the latter was divided into 2 subgroups (mesh [MIM] and suture [MIS]). Patients were classified using the HERNIAscore. Hernias were diagnosed by clinical and/or CT examination.

Results

A total of 182 out of 210 surgical patients were included. After a median follow-up of 13.0 months, 39 IH (21.9%) were detected, 23 of which (13.4%) were in the EI; their frequency was lower in the TI group (3.4%) and in the MIM group (5.9%) than in the MIS group (29.5%; p = 0.007). The probability of developing IH in the MIS group showed an OR = 11.7 (95%CI: 3.3-42.0) compared to the TI group and 4.3 (IC 95%: 1.1-16.3) versus the MIM group.

Conclusions

The location of the incision is relevant to avoid incisional hernias. Transverse incisions should be used as the first option. When a midline incision is needed, a prophylactic mesh could be considered in high risk patients because it is safe and associated with low morbidity.  相似文献   
55.
Clinical Oral Investigations - The aim of this study was the analysis of WNT10A variants in seven families of probands with various forms of tooth agenesis and self-reported family history of...  相似文献   
56.
Background: Egyptian street youth use substances including tobacco, illicit drugs, and pharmaceutical drugs. To understand the circumstances, including adverse childhood experiences, that place adolescents at risk for engaging in substance use, we conducted in-depth interviews among a sample of Egyptian street children. Methods: From youth residing at or attending Caritas, a non-profit organization, which provides shelter and education to street youth, seven girls and twelve boys, aged 12–18 years, participated in open-ended, in-depth interviews. Results: Eight out of the 19 participants reported family history (early exposure) to substance use; and seven of them were initiated by either a family member (sibling), friend or coworker. Most of the participants reported a history of conflict with or abuse (verbal or physical) by their parents or siblings, or stressful situations at home; they used substance(s) to alleviate their stress. Few attended school, and some were forced to work and help their family. Conclusions: Among Egyptian youth, adverse childhood experiences, such as poverty, child abuse, and family substance use, challenge somewhat susceptible youths and lead them to the path of substance use and addiction. Prevention intervention should be multifaceted, culturally adaptable, and primarily targeting the social environment during childhood.  相似文献   
57.
Food-grade titanium dioxide (E171) is widely used as a food additive, and it is known that after oral consumption, E171 is translocated into the bloodstream reaching the highest titanium level at 6 h. E171 is accumulated in some organs triggering toxicity, but the effects on the blood parameters after oral consumption have been less studied. Recently, evidence shows that oral exposure to E171 induces behavioral signs of anxiety and depression. The relation between blood alterations and psychiatric disorders has been previously demonstrated. However, the oral exposure to E171 effects on alterations in blood parameters and effects linked to alterations in animal behavior has not been explored. In this short communication, we aimed to investigate the effects of E171 on specific blood parameters (hematocrit, hemoglobin, number of erythrocytes, and leukocytes) and anxiety and compulsive-like behavior in males and females orally exposed to ~5 mg/kg for 4 weeks. The results showed that E171 decreased hematocrit and hemoglobin in male but not in female mice while leukocyte and erythrocyte count remained unaltered. Oral consumption of E171 decreased the levels of anxiety-like behavior in females but not in male mice, while compulsive-like behavior was increased in both male and female mice.  相似文献   
58.
59.
目的 通过比较全身运动(GMs)评估正常的高危儿单纯家庭康复训练与家庭康复训练联合药物干预的预后,分析GMs对高危儿早期干预的指导意义。方法 选取2016年2月-2017年2月于潍坊市妇幼保健院康复科就诊并接受GMs评估正常的183例高危儿,随机分组为观察组和对照组,观察组为单纯家庭康复训练组89例,对照组为家庭康复训练联合药物干预组94例。采用Peabody运动发育量表对两组患儿分别于纠正月龄6、9、12个月龄进行评估,对Peabody运动发育量表中各指标应用SPSS 21.0进行统计分析。结果 干预后,纠正月龄6、9、12个月龄时,观察组和对照组Peabody运动发育量表中粗大运动商(GMQ)、精细运动商(FMQ)、总运动商(TMQ)比较,差异无统计学意义(P>0.05),重复测量方差分析发现观察组和对照组的GMQ、FMQ、TMQ评分的组间效应差异无统计学意义(P>0.05),时间效应差异有统计学意义(P<0.05),干预因素与时间因素不存在交互作用(P>0.05)。结论 GMs评估对高危儿早期干预具有指导意义。GMs评估正常者,家庭康复训练可达到促进高危儿运动功能发育的目的 ,避免仅因系高危儿而采取“过度干预”。  相似文献   
60.
目的:探讨轴向载荷分担比用于胫腓骨骨干骨折术后指导外固定器轴向动力化促进骨折愈合的有效性。方法:选取外固定器治疗的胫腓骨骨干骨折患者100例,随机分为观察组50例,对照组50例。观察组在轴向载荷分担比指导下行外固定器轴向动力化治疗,对照组未行动力化,随访比较两组的治疗效果。结果:所有患者均获随访,随访时间4~12个月,平均6.5个月,治疗期间所有患者均未出现外固定针断裂、松动及再骨折等并发症,观察组1例骨搬移患者轴向载荷分担比5%,X线片显示骨折断端有连续性骨痂通过,拆除外固定器连接杆后发生移位,恢复原数值行轴向加压再动力化,现已愈合。观察组除外1例骨搬移患者,其余49例患者外固定器固定时间为[(24.4±4.7)周],骨折临床愈合时间为[(22.4±4.7)周],与对照组50例患者外固定器固定时间[(29.3±5.6)周],骨折临床愈合时间[(27.3±5.6)周]比较,显著减少(P0.05)。结论:外固定器轴向载荷分担比指导胫腓骨骨干骨折外固定术后轴向动力化可以加速骨折愈合,但不适合骨搬移截骨端已硬化患者。  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