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   184165篇
  免费   18066篇
  国内免费   11805篇
耳鼻咽喉   1637篇
儿科学   1916篇
妇产科学   2429篇
基础医学   22010篇
口腔科学   3287篇
临床医学   24250篇
内科学   27021篇
皮肤病学   2214篇
神经病学   9572篇
特种医学   6512篇
外国民族医学   97篇
外科学   18947篇
综合类   29963篇
现状与发展   39篇
一般理论   22篇
预防医学   12338篇
眼科学   4817篇
药学   19875篇
  195篇
中国医学   11349篇
肿瘤学   15546篇
  2024年   2394篇
  2023年   3089篇
  2022年   7841篇
  2021年   9852篇
  2020年   7580篇
  2019年   6404篇
  2018年   6666篇
  2017年   6153篇
  2016年   5758篇
  2015年   8745篇
  2014年   10593篇
  2013年   9796篇
  2012年   14285篇
  2011年   15404篇
  2010年   9835篇
  2009年   7561篇
  2008年   10053篇
  2007年   9571篇
  2006年   9134篇
  2005年   8878篇
  2004年   5679篇
  2003年   5143篇
  2002年   4263篇
  2001年   3608篇
  2000年   3802篇
  1999年   3854篇
  1998年   2288篇
  1997年   2347篇
  1996年   1786篇
  1995年   1739篇
  1994年   1511篇
  1993年   907篇
  1992年   1282篇
  1991年   1117篇
  1990年   900篇
  1989年   847篇
  1988年   765篇
  1987年   623篇
  1986年   458篇
  1985年   396篇
  1984年   190篇
  1983年   162篇
  1982年   93篇
  1981年   123篇
  1980年   79篇
  1979年   109篇
  1978年   52篇
  1977年   51篇
  1976年   42篇
  1974年   44篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
In the previous research, we found that anticancer agent LS-1-2F could cause the vacuolation of tumor cells. Herein we investigated the effect of compound LS-1-2F on the endocytosis of macromolecules, including fluorescence quantum dots, human serum albumin, single-stranded RNA, and monoclonal antibody, into tumor cells. We found that LS-1-2F could accelerate the endocytosis of these large molecules by laser confocal microscope and flow cytometry. The effect of LS-1-2F on the improvement of the internalization efficiency of Herceptin biosimilar was particularly significant. Promoting endocytosis will help increase the efficiency of liquid-phase drug uptake in drug-resistant cancer cells and could potentially facilitate the use of drugs in nanoparticle delivery vehicles.  相似文献   
12.
目的探讨双胎贫血-红细胞增多序列征(TAPS)的临床特点,并进行文献复习。 方法选择2016年5月,四川大学华西第二医院新生儿科收治的单绒毛膜双羊膜囊(MCDA) TAPS新生儿(新生儿1、2)为研究对象。采用回顾性分析方法,收集本对TAPS新生儿的临床病例资料,对其临床特点进行分析。本研究对TAPS文献进行复习时,设定检索策略为:以"双胎贫血红-细胞增多序列征"为关键词,在中国知网、维普中文科技期刊数据库、万方数据知识服务平台中,检索TAPS相关文献,检索时间设定为各数据库建库至2018年8月31日。总结TAPS的临床特点及其诊断、治疗与预后。本研究遵循的程序符合2013年修订的《世界医学协会赫尔辛基宣言》要求。 结果①对本对TAPS新生儿母亲的临床资料采集如下:29岁,自然受孕,G1P0,孕龄为11+6孕周时,于本院建卡进行定期产前检查,乙型肝炎病毒携带病史20年(接受定期随访);孕龄为16+5孕周时,超声检查提示MCDA双活胎。于孕龄为36+4孕周时发现重度妊娠期肝内胆汁淤积症,予以地塞米松促胎肺成熟、保肝及降胆汁酸等治疗1 d后,经剖宫产术分娩一对活男婴。②对本对TAPS新生儿的临床资料采集如下:均为男性,出生胎龄为36+5周。其中,新生儿1:出生体重为2 420 g,生后1、5、10 min Apgar评分均为10分,生后1 h+58 min转入本院新生儿科,全身皮肤红紫,胃管内反复抽出咖啡色胃液,穿刺部位、脐带残端可见渗血。转入本院新生儿科时,血红蛋白(Hb)值为278 g/L,血细胞比容为78.4%,网织红细胞百分比为3.0%,诊断为红细胞增多症等。新生儿2:出生体重为1 870 g,生后1、5、10 min Apgar评分均为10分,生后34 min转入本院新生儿科,全身皮肤苍白、反应差,竖颈差,四肢肌张力减低,原始反射减弱,转入本院新生儿科时,Hb值为63 g/L,血细胞比容为21.2%,网织红细胞百分比为39.7%,诊断为重度新生儿贫血等。新生儿1、2的Hb差值为215 g/L,并且新生儿2与新生儿1网织红细胞百分比的比值为13.2,确诊为TAPS双胎新生儿。新生儿1、2均合并多系统并发症,分别予以部分换血、输血治疗后好转出院,生后随访1年,生长发育均正常。③文献复习结果:按照本研究设定的文献检索策略,共计检索出7篇报道TAPS研究的文献,涉及25对(50例)TAPS新生儿/胎儿的临床特点、诊治及预后等方面研究。其中,受血儿均表现为多血貌,供血儿均表现为贫血貌。50例TAPS新生儿/胎儿的治疗结局为:37例(74.0%)好转出院,1例(2.0%)纳入原始研究时尚未娩出,9例(18.0%)死亡,2例(4.0%)因严重并发症放弃治疗后结局不详,1例(2.0%)新生儿因气腹征转院接受进一步治疗后失访。在37例好转出院的TAPS新生儿中,4例(10.8%)合并低白蛋白血症,4例(10.8%)合并神经系统损害,22例(59.5%)合并心血管系统并发症,14例(37.8%)合并呼吸系统并发症,14例(37.8%)合并新生儿黄疸;对其均缺乏长期随访,长期预后均不详。 结论国内报道的TAPS多于生后才被确诊,新生儿临床特点主要为MCDA新生儿的生后Hb差值大(>80 g/L),而羊水量差异不明显,可合并多系统并发症,其长期预后目前尚不明确。对MCDA新生儿的大脑中动脉峰值流速(MCA-PSV)测定与胎盘超声检查,可协助临床于产前尽早诊断TAPS。  相似文献   
13.
14.
15.
正患者女,40岁,身高160 cm,体质量52 kg,因2 d前无明显诱因出现左下腹部持续性绞痛,于2018年10月19日急诊入院,体温37.7℃,脉搏112次/分,伴稍恶心,无呕吐、放射痛、发热,无腹泻、血便,无尿频、尿痛等症状。1 d前曾在当地社区医院以"急性肠炎"给予抗感染、解痉等治疗,自觉症状有所缓解,次日午间症状再次加重。查体:左下腹压痛(+)、反跳痛(+),局部腹肌紧张明显。行腹部CT平扫检查示:结肠走行反位,右半结肠位于左上腹,阑尾增粗伴周围渗出,周围间隙模糊,阑尾最粗约1.7 cm,临近盲肠壁稍增厚;胃腔大部分位于右侧,十二指肠垂直下行,可见Ladd束带;肝脏体积明显增大;脾脏受推挤,位于左侧肾上腺前方(图1~3)。诊  相似文献   
16.
Icariin (ICA) is obtained from Epimedium brevicornu maxim and exploited to remedy miscellaneous cancers. But the role of ICA in medulloblastoma remains hazy. The research delved into the antitumor activity of ICA in medulloblastoma DAOY cells. ICA with diverse concentrations was utilized to stimulate DAOY cells, and the biological functions of ICA in medulloblastoma DAOY cells were examined. Then, the relative SPARC expression was determined in ICA‐managed DAOY cells, and the pc‐SPARC vector was transfected into DAOY cells to further probe the influence of SPARC and JAK1/STAT3 and PI3K/AKT pathways in ICA‐managed DAOY cells. A xenograft model was established to investigate the function of ICA in vivo. ICA restrained cell viability, expedited apoptosis, prohibited cell migration and invasion, and meanwhile affected the associative factors expression in DAOY cells. Additionally, SPARC expression was declined in ICA‐stimulated DAOY cells. Overexpressed SPARC reversed the functions of ICA in above‐involved cell behaviors of DAYO cells and the correlative protein levels. Besides, ICA notably frustrated JAK1/STAT3 and PI3K/AKT activations in DAOY cells. Beyond that, ICA prohibited tumor formation in vivo. The results concluded that ICA exhibited the antitumor activity in DAOY cells via decreasing SPARC and inactivating JAK1/STAT3 and PI3K/AKT pathways.  相似文献   
17.
Visceral fat loss in response to four‐cycle ergometer training regimens with explicit differences in exercise intensity and modality was compared. Fifty‐nine obese young women (body fat percentage ≥ 30%) were randomized to a 12‐week intervention consisting of either all‐out sprint interval training (SITall‐out, n = 11); supramaximal SIT (SIT120, 120% O2peak, n = 12); high‐intensity interval training (HIIT90, 90% O2peak, n = 12), moderate‐intensity continuous training (MICT, 60% O2peak, n = 11), or no training (CON, n = 13). The total work done per training session in SIT120, HIIT90, and MICT was confined to 200 kJ, while it was deliberately lower in SITall‐out. The abdominal visceral fat area (AVFA) was measured through computed tomography scans. The whole‐body and regional fat mass were assessed through dual‐energy X‐ray absorptiometry. Pre‐, post‐, and 3‐hour post‐exercise serum growth hormone (GH), and epinephrine (EPI) were measured during selected training sessions. Following the intervention, similar reductions in whole‐body and regional fat mass were found in all intervention groups, while the reductions in AVFA resulting from SITall‐out, SIT120, and HIIT90 (>15 cm2) were greater in comparison with MICT (<3.5 cm2, P < .05). The AVFA reductions among the SITs and HIIT groups were similar, and it was concomitant with the similar exercise‐induced releases of serum GH and EPI. CON variables were unchanged. These findings suggest that visceral fat loss induced by interval training at or above 90% O2peak appeared unresponsive to the change in training intensity. Nonetheless, SITall‐out is still the most time‐efficient strategy among the four exercise‐training regimes for controlling visceral obesity.  相似文献   
18.
Lin  Hua  Li  Muwei  Zhan  Yang  Lin  Li  Yang  Kun  Hu  Shimin  Han  Ying 《Brain imaging and behavior》2021,15(4):1739-1747

The ε4 allele of the APOE gene is thought to increase risk from amnestic mild cognitive impairment (aMCI) to Alzheimer’s disease. Cognitive decline in the condition is increasingly considered to worsen functional disconnections in brain network composed of gray matter and white matter. Nevertheless, Whether APOEε4 targets specific white matter functional connectivity in patients with aMCI remains mostly unexplored, mainly due to the challenges of detecting BOLD signals in white matter. Here, we applied a novel approach to investigate APOEε4-related specific bundles and cortical area alterations in aMCI subjects, in order to characterize white matter-gray matter functional connectivity differences throughout the brain. We analyzed 75 patients with aMCI and 76 demographically matched normal controls. The aMCI APOEε4 carriers showed decreased functional connectivity located at left corticospinal tract, bilateral posterior limb of internal capsule, and right temporopolaris, which was different from the regions of aMCI-related changes. We further found that recognition scores were positively associated with the right temporopolaris in aMCI APOEε4 carriers. Collectively, the data provide new evidence that APOEε4 genotype exerts a negative impact on neural activity in both gray and white matter in aMCI, which potentially contributes to functional disconnection and memory decline. A novel method provides full-scale measuring effect of disease conditions on functional architecture throughout the brain. Trial registration: https://www.ClinicalTrials.gov (Identifier: NCT02225964). Registered January 2014.

  相似文献   
19.
李玉清  杨春霞 《北京中医药》2006,25(11):643-645
目的 研究补肺活血法治疗慢性阻塞性肺疾病缓解期的临床疗效和对肺功能的影响.方法 将125例患者随机分为治疗组85例和对照组40例,两组均经缓解期常规基础治疗,治疗组加用中药汤剂口服.两组均以2周为1个疗程,连续治疗4个疗程后统计疗效.结果 治疗组总有效率为94.1%,对照组总有效率为90.0%,两组相比,P<0.05;两组的主要症状和体征均改善,但治疗组对咳嗽、咳痰、喘促、气短以及肺部罗音等症状体征改善均优于对照组(P<0.01);治疗组的肺功能的改善优于对照组(P<0.05);治疗组的发病次数明显少于对照组(P<0.05).结论 补肺活血法能有效改善慢性阻塞性肺疾病缓解期患者的临床症状、体征、肺功能,减少患者发病次数,并提高其生活质量.  相似文献   
20.
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