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   78329篇
  免费   7757篇
  国内免费   5207篇
耳鼻咽喉   670篇
儿科学   1182篇
妇产科学   960篇
基础医学   7991篇
口腔科学   1472篇
临床医学   10801篇
内科学   10486篇
皮肤病学   907篇
神经病学   3445篇
特种医学   2569篇
外国民族医学   35篇
外科学   5863篇
综合类   15524篇
现状与发展   25篇
一般理论   11篇
预防医学   7065篇
眼科学   2057篇
药学   8987篇
  73篇
中国医学   5546篇
肿瘤学   5624篇
  2024年   272篇
  2023年   1082篇
  2022年   2672篇
  2021年   3542篇
  2020年   2908篇
  2019年   2322篇
  2018年   2410篇
  2017年   2586篇
  2016年   2249篇
  2015年   3389篇
  2014年   4417篇
  2013年   4521篇
  2012年   6464篇
  2011年   6817篇
  2010年   5024篇
  2009年   4231篇
  2008年   4844篇
  2007年   4742篇
  2006年   4439篇
  2005年   4027篇
  2004年   2839篇
  2003年   2627篇
  2002年   2272篇
  2001年   1744篇
  2000年   1534篇
  1999年   1253篇
  1998年   772篇
  1997年   722篇
  1996年   544篇
  1995年   549篇
  1994年   468篇
  1993年   291篇
  1992年   375篇
  1991年   363篇
  1990年   279篇
  1989年   271篇
  1988年   239篇
  1987年   226篇
  1986年   181篇
  1985年   140篇
  1984年   87篇
  1983年   96篇
  1982年   35篇
  1981年   47篇
  1980年   47篇
  1979年   40篇
  1978年   32篇
  1977年   25篇
  1973年   38篇
  1972年   27篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
目的对不同季铵化程度(DQ)的N-三甲基壳聚糖(TMC)促进阿昔洛韦(ACV)滴眼液眼部滞留性进行考察。方法将浓度为0.5%,DQ分别为20%、40%及60%的TMC(TMC20,TMC40,TMC60)加入ACV滴眼液中;以同浓度壳聚糖(CS)ACV滴眼液为阳性对照,以普通ACV滴眼液为阴性对照,选用家兔为实验动物,采用悬挂泡技术和束缚泡技术进行离体眼球表面接触角及解吸附动力学进行研究,同时在各种ACV滴眼液中分别加入0.05%的荧光素钠为示踪剂,在体研究各种ACV滴眼液在家兔眼部的滞留性。结果与普通ACV滴眼液相比,含CS及TMC的滴眼液在角膜表面的接触角明显降低,解吸时间及在体滞留时间明显延长(P<0.05);与同浓度的CS ACV阳性对照相比,TMC20促进滞留作用较弱,而TMC40作用差异无显著性(P>0.05),而TMC60的作用明显较强(P<0.05)结论 TMC可显著增加ACV的眼部滞留性,且与其DQ呈正相关。  相似文献   
3.
4.
孙淑荣  董玲 《医学综述》2015,(2):257-259
妊娠妇女随着孕周的增加,其本身及胎儿代谢产物逐渐增多,加之循环血容量增加,使肾脏总体负荷加重,容易并发肾损害。妊娠期高血压疾病是妊娠期特有的疾病,其病理生理变化为全身小血管痉挛、内皮损伤及局部缺血;肾脏最先受累。严重的肾损害会导致较高的母儿患病率和病死率,而肾脏损害存在无症状阶段,通过筛查才能发现相对早期的肾损害。探索妊娠期高血压疾病早期肾损害敏感性指标,可早发现、早干预,从而减少不良产科结局。  相似文献   
5.
Objective: To study the biomechanical mechanism of head injuries beaten with sticks, which is common in the battery or assaultive cases. Methods: In this study, the Hybrid-III anthropomorphic test device and finite element model (FEM) of the total human model for safety (THUMS) head were used to determine the biomechanical response of head while being beaten with different sticks. Total eight Hybrid-III tests and four finite element simulations were conducted. The contact force, resultant acceleration of head center of gravity, intracranial pressure and von Mises stress were calculated to determine the different biomechanical behavior of head with beaten by different sticks. Results: In Hybrid-III tests, the stick in each group demonstrated the similar kinematic behavior under the same loading condition. The peak values of the resultant acceleration for thick iron stick group, thin iron stick group, thick wooden stick group and thin wooden stick group were 203.4 g, 221.1 g, 170.5 g and 122.2 g respectively. In finite element simulations, positive intracranial pressure was initially observed in the frontal comparing with negative intracranial pressure in the contra-coup site. Subsequently the intracranial pressure in the coup site was decreasing toward negative value while the contra-coup intracranial pressure increasing toward positive values. Conclusions: The results illustrated that the stiffer and larger the stick was, the higher the von Mises stress, contact force and intracranial pressure were. We believed that the results in the Hybrid-III tests and THUMS head simulations for brain injury beaten with sticks could be reliable and useful for better understanding the injury mechanism.  相似文献   
6.
目的 解析真实世界中乳腺恶性肿瘤患者的人群特征、诊断特征、中西医用药特征,为乳腺癌的临床防治提供参考。方法 采集2002年2月至2015年5月全国60家三级甲等医 院信息系统(Hospital Information System,HIS)中,出院诊断为“乳腺癌”的患者用药信息,采用SAS9.3统计软件,对人口学信息、诊断信息、医嘱用药信息等进行描述性分析。结果 39798例乳腺癌患者,平均年龄(50.93者,平均年龄)岁;多以门诊入院,入院病情以“一般”为主;合并疾病主要为高血压,骨肿瘤,联用西药以抑制肿瘤细胞增殖、治疗并发症、缓解放化疗不良反应为主;中医辨证以痰瘀互结证,气阴两虚证,肝气淤滞证,脾气亏虚证型最为常见,临床清热解毒剂、益气扶正剂,活血化瘀剂应用较多。结论 乳腺癌中西医结合治疗,联用药物广泛,临床治疗基本符合临床指南。  相似文献   
7.
Mammalian spermatogenesis is a well-organized process of cell development and differentiation. Meiosis expressed gene 1 (MEIG1) plays an essential role in the regulation of spermiogenesis. To explore potential mechanisms of MEIG1''s action, a yeast two-hybrid screen was conducted, and several potential binding partners were identified; one of them was membrane occupation and recognition nexus repeat containing 3 (MORN3). MORN3 mRNA is only abundant in mouse testis. In the testis, Morn3 mRNA is highly expressed in the spermiogenesis stage. Specific anti-MORN3 polyclonal antibody was generated against N-terminus of the full-length MORN3 protein, and MORN3 expression and localization was examined in vitro and in vivo. In transfected Chinese hamster ovary cells, the antibody specifically crossed-reacted the full-length MORN3 protein, and immunofluorescence staining revealed that MORN3 was localized throughout the cytoplasm. Among multiple mouse tissues, about 25 kDa protein, was identified only in the testis. The protein was highly expressed after day 20 of birth. Immunofluorescence staining on mixed testicular cells isolated from adult wild-type mice demonstrated that MORN3 was expressed in the acrosome in germ cells throughout spermiogenesis. The protein was also present in the manchette of elongating spermatids. The total MORN3 expression and acrosome localization were not changed in the Meig 1-deficient mice. However, its expression in manchette was dramatically reduced in the mutant mice. Our studies suggest that MORN3 is another regulator for spermatogenesis, probably together with MEIG1.  相似文献   
8.
Phytonutrients extracted from natural resources are receiving much attention among researchers due to their highly antioxidative characteristics which prevent several degenerative diseases including cardiovascular diseases and cancers. These nutraceutical compounds can be used in food, pharmaceutical and cosmetic products as natural antioxidants, preservatives, colourants and functional foods. Huge volume of food wastes are generated from the processing industry and these low-value food residues are rich in various phytonutrients worth recovering. This approach of valorisation reduces the generation of food wastes and is cost-effective considering the cheap feedstock, reduced waste management expenses and high market value of extracted compounds. In light of the health and safety risks posed by commonly used organic extraction solvents derived from the petrochemical industry, there is a need to recover the phytonutrients using green, sustainable and efficient solvents that are safe for human consumption. This work discusses ethyl lactate as a safe, green, efficient and potentially cheap solvent to recover phytonutrients from fruit and vegetable by-products. Ethyl lactate is compared with other organic solvents commonly used from the aspects of safety, environmental impacts and efficiency. Current challenges when employing ethyl lactate are also discussed.  相似文献   
9.
10.
目的为了解尘肺病患者心理状况及社会支持对患者心理健康的影响,为对尘肺病患者建立干预措施提供技术支撑。方法采用SCL-90症状清单、社会支持量表对在全省尘肺病住院病人较多的3家医院进行尘肺病患者问卷调查。结果 208名尘肺病患者男性205人,女性3人。文化程度均为高中及以下;Ⅰ期尘肺148人,Ⅱ期尘肺41人,Ⅲ期尘肺19人;尘肺患者SCL-90症状清单总分为162.00±64.77,低于全国常模,差异有统计学意义(P0.05);不同分期、不同年齡段、不同病程尘肺病患者各组之间社会支持得分差异无统计学意义。结论尘肺病患者心理健康水平低于全国水平,社会支持各维度得分与SCL-90各因子得分呈负相关,建立尘肺病患者心理干预体系十分必要。  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