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   14555篇
  免费   1649篇
  国内免费   444篇
耳鼻咽喉   60篇
儿科学   1452篇
妇产科学   443篇
基础医学   1136篇
口腔科学   219篇
临床医学   2134篇
内科学   2148篇
皮肤病学   128篇
神经病学   673篇
特种医学   592篇
外国民族医学   4篇
外科学   1195篇
综合类   1941篇
一般理论   1篇
预防医学   1618篇
眼科学   511篇
药学   1352篇
  9篇
中国医学   533篇
肿瘤学   499篇
  2024年   7篇
  2023年   250篇
  2022年   284篇
  2021年   504篇
  2020年   584篇
  2019年   684篇
  2018年   643篇
  2017年   657篇
  2016年   613篇
  2015年   596篇
  2014年   1040篇
  2013年   1251篇
  2012年   894篇
  2011年   945篇
  2010年   769篇
  2009年   668篇
  2008年   667篇
  2007年   701篇
  2006年   607篇
  2005年   539篇
  2004年   439篇
  2003年   425篇
  2002年   344篇
  2001年   332篇
  2000年   263篇
  1999年   201篇
  1998年   164篇
  1997年   175篇
  1996年   161篇
  1995年   112篇
  1994年   142篇
  1993年   99篇
  1992年   93篇
  1991年   89篇
  1990年   63篇
  1989年   72篇
  1988年   60篇
  1987年   53篇
  1986年   41篇
  1985年   71篇
  1984年   64篇
  1983年   46篇
  1982年   56篇
  1981年   53篇
  1980年   40篇
  1979年   18篇
  1978年   20篇
  1977年   16篇
  1976年   14篇
  1975年   8篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
目的比较飞秒激光制瓣准分子激光原位角膜磨镶术(FS-LASIK)、全飞秒激光小切口角膜基质透镜取出术(SMILE)和有晶状体眼后房型人工晶状体(ICL V4c)植入术三者矫正中低度近视的效果。方法采用回顾性研究。以惠州爱尔眼科医院2019年6月至2020年4月矫正中低度近视120例(120眼)作为研究对象,受术者分为FS-LASIK组、SMILE组及ICL组,每组40例(40眼),各组分别接受相应的手术,术后随访3个月比较其矫正效果。结果术后1个月及3个月,3组间视力及有效性指数对比差异无统计学意义(P>0.05);ICL组安全性指数高于SMILE组及FS-LASIK组(P<0.05)。术后3个月FS-LASIK组的三叶草像差、彗差和球差出现明显变化,而SMILE组的变化较小,ICL组变化最小(P<0.05)。结论对中低度近视FS-LASK、SMILE及ICL植入术三者均有确切疗效,而ICL V4c植入术的安全性最高,患者的视觉质量最好。  相似文献   
2.
3.
《Vaccine》2021,39(14):1933-1942
The genetic and antigenic drift associated with the high pathogenicity avian influenza (HPAI) viruses of Goose/Guangdong (Gs/GD) lineage and the emergence of vaccine-resistant field viruses underscores the need for a broadly protective H5 influenza A vaccine. Here, we tested experimental vector herpesvirus of turkey (vHVT)-H5 vaccines containing either wild-type clade 2.3.4.4A-derived H5 inserts or computationally optimized broadly reactive antigen (COBRA) inserts with challenge by homologous and genetically divergent H5 HPAI Gs/GD lineage viruses in chickens. Direct assessment of protection was confirmed for all the tested constructs, which provided clinical protection against the homologous and heterologous H5 HPAI Gs/GD challenge viruses and significantly decreased oropharyngeal shedding titers compared to the sham vaccine. The cross reactivity was assessed by hemagglutinin inhibition (HI) and focus reduction assay against a panel of phylogenetically and antigenically diverse H5 strains. The COBRA-derived H5 inserts elicited antibody responses against antigenically diverse strains, while the wild-type-derived H5 vaccines elicited protection mostly against close antigenically related clades 2.3.4.4A and 2.3.4.4D viruses. In conclusion, the HVT vector, a widely used replicating vaccine platform in poultry, with H5 insert provides clinical protection and significant reduction of viral shedding against homologous and heterologous challenge. In addition, the COBRA-derived inserts have the potential to be used against antigenically distinct co-circulating viruses and future drift variants.  相似文献   
4.
5.
本文旨在探讨影响新疆低温乳消费市场的限制性因素及相应的对策。调研通过网络调查问卷和实地调研走访相结合的方式,从乳制品消费结构、消费能力,低温奶认知、低温奶购买意愿、购买便利性、购买偏好及健康饮奶习惯等方面分析影响新疆低温乳消费市场的因素。结果显示:32.93%的消费者不了解乳中生物活性物质(如乳铁蛋白)的热敏性,39.97%的消费者不能区分各类液态乳产品,47.64%的消费者有煮沸巴氏杀菌乳后饮用的习惯;43.21%的消费者"担心未消毒彻底,存在细菌",36.30%的消费者认为"加热后可增加营养价值和香味";72.64%的消费者曾感到"购买巴氏杀菌乳不方便";54.85%的消费者认为本地品牌"更新鲜、更健康"。结果启示:本地乳企应该充分利用在当地的良好品牌信誉度和牧场资源,尽早布局低温奶市场,通过研发高品质低温乳制品、普及科学饮奶理念、改善冷链物流能力、完善购物体验和精细化服务能力等手段,提高生产竞争力,抵御进口乳制品和常温乳对当地乳品市场的冲击,占领区域低温奶消费市场。  相似文献   
6.
7.

Objective

To identify practices, attitudes, and beliefs associated with intake of traditional foods among Alaska Native women.

Design

Cross-sectional study that measured traditional food intake; participation in food-sharing networks; presence of a hunter or fisherman in the home; the preference, healthfulness, and economic value of traditional foods; and financial barriers to obtaining these foods.

Participants

Purposive sample of 71 low-income Alaska Native women receiving Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) assistance in Anchorage, AK.

Analysis

Bivariate and multivariate regression analyses.

Results

Traditional foods contributed 4% of total daily calories. Given a choice, 63% of participants indicated that they would prefer half or more of the foods they ate to be traditional (ie, not store-bought). The majority of participants (64%) believed that traditional foods were healthier than store-bought foods. Of all participants, 72% relied on food-sharing networks for traditional foods; only 21% acquired traditional foods themselves. Participants who ate more traditional foods preferred traditional foods (B?=?.011 P?=?.02).

Implications for Research and Practice

Traditional food intake was low and findings suggested that Alaska Native women living in an urban setting prefer to consume more but are unable to do so. Future research might examine the effect of enhancing social networks and implementing policies that support traditional food intake.  相似文献   
8.
The sinonasal tract is host to numerous benign and malignant entities that can pose diagnostic challenges to pathologists as a result of limited exposure in daily practice. This review concentrates on certain key characteristics of select entities with focus on differential diagnosis, novel subtypes and/or molecular distinction. The aim of this review is to summarize current knowledge and shed light on diagnostically challenging and emerging entities in sinonasal tract pathology.  相似文献   
9.
Isotretinoin (ISO) is a first‐generation retinoid discovered in 1952 and approved by the FDA for the treatment of nodulocystic acne in 1982. The anti‐inflammatory properties of ISO have found its use in disorders other than acne. ISO can create psychiatric problems, including depression and suicidal ideation. These neuropsychiatric problems are very similar to disorders secondary to hyperhomocysteinemia (HHcy), vitamin B12, and folic acid (vitamin B9) deficiencies. Given that previous literature suggested folate supplementation improved the efficacy of traditional antidepressant medications, clinicians may wish to consider folate supplementation for patients with depression or possible depressive symptoms, such as acne patients with genetic susceptibility. Brain‐derived neurotrophic factor may be a cytokine‐specific screening biomarker in immune‐based antidepressive therapy.  相似文献   
10.
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