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   420836篇
  免费   31707篇
  国内免费   17106篇
耳鼻咽喉   4868篇
儿科学   13207篇
妇产科学   4825篇
基础医学   48607篇
口腔科学   9367篇
临床医学   42406篇
内科学   74676篇
皮肤病学   7284篇
神经病学   19987篇
特种医学   17534篇
外国民族医学   150篇
外科学   52893篇
综合类   53141篇
现状与发展   84篇
预防医学   20421篇
眼科学   7756篇
药学   39859篇
  132篇
中国医学   13397篇
肿瘤学   39055篇
  2023年   5020篇
  2022年   7594篇
  2021年   17263篇
  2020年   12355篇
  2019年   17549篇
  2018年   12578篇
  2017年   12381篇
  2016年   14853篇
  2015年   18122篇
  2014年   29740篇
  2013年   28642篇
  2012年   30023篇
  2011年   28353篇
  2010年   24756篇
  2009年   24004篇
  2008年   23131篇
  2007年   23338篇
  2006年   20645篇
  2005年   16009篇
  2004年   11430篇
  2003年   9976篇
  2002年   8211篇
  2001年   7008篇
  2000年   5928篇
  1999年   4820篇
  1998年   5050篇
  1997年   4608篇
  1996年   3611篇
  1995年   3685篇
  1994年   3406篇
  1993年   2745篇
  1992年   2672篇
  1991年   2413篇
  1990年   2181篇
  1989年   2044篇
  1988年   1913篇
  1987年   1598篇
  1986年   1395篇
  1985年   2487篇
  1984年   2513篇
  1983年   1805篇
  1982年   1934篇
  1981年   1798篇
  1980年   1557篇
  1979年   1305篇
  1978年   1009篇
  1977年   952篇
  1976年   838篇
  1975年   496篇
  1974年   509篇
排序方式: 共有10000条查询结果,搜索用时 687 毫秒
81.
Recent years have brought an enhanced understanding of keratinocyte contribution to cutaneous nociception. While intra‐epidermal nerve endings were classically considered as the exclusive transducers of cutaneous noxious stimuli, it has now been demonstrated that epidermal keratinocytes can initiate nociceptive responses, like Merkel cells do for the innocuous mechanotransduction. In the light of recent in vivo findings, this article outlines this paradigm shift that points to a not yet considered population of sensory epidermal cells.  相似文献   
82.
We report two British cases of liver abscess, due to Klebsiella pneumoniae and associated with synchronous infection elsewhere, which required liver resection for definitive treatment. They illustrate the geographic spread of aggressive K pneumoniae liver infection and demonstrate the importance of early aggressive treatment.  相似文献   
83.
目的:探讨3D-CRT 低剂量区 V5体积的大小对非小细胞肺癌患者肺功能的影响。方法:收集我院肿瘤科2014年4月~2015年10月收治的46例首次行三维适形放射治疗且顺利完成治疗的非小细胞肺癌患者,对每例患者分别在治疗前以及治疗后的1、3个月进行肺功能检测,分析3D-CRT 低剂量区 V5体积的大小与肺功能变化之间的关系。结果:放疗后1个月的 FEV1%、FVC%值明显高于放疗前且差异均具有显著性。放疗后1个月、3个月的 DLCO%值明显低于放疗前,且放疗前的与放疗后3个月的差异具有显著性;V5≦45%、45%55%三组放疗前后的 FEV1%值和 FVC%值比较差异均不具有显著性。V5≦45%、45%55%三组放疗前后的 DLCO%值均呈逐渐下降趋势,且 V5>55%组的放疗前后 DLCO%值比较差异具有显著性。而 V5≦45%组和45%55%时,DLCO%值降低的趋势更加显著。  相似文献   
84.
目的探讨神经内镜辅助下经鼻蝶入路切除鞍区肿瘤的方法和优势。方法回顾性分析30例鞍区肿瘤病人的临床资料,垂体腺瘤26例(其中无功能垂体腺瘤6例、泌乳素瘤16例、垂体生长激素腺瘤4例),拉克囊肿1例,胆脂瘤1例,脑膜瘤1例,颅咽管瘤1例。采用神经内镜辅助下经鼻蝶入路手术切除肿瘤。结果肿瘤全切27例,部分切除3例。术后3例发生脑脊液鼻漏,经腰大池持续引流后痊愈。无死亡病例。随访3~6个月,病人恢复良好。结论在神经内镜辅助下经鼻蝶入路治疗鞍区肿瘤,较单纯的显微镜手术治疗创伤更小,肿瘤全切率更高。  相似文献   
85.
目的:观察清肝解郁和健脾补肾法治疗肝火上亢型慢性肾衰(CRF)合并高血压患者的临床效果。方法:选取2016年6月至2018年6月京东誉美医院收治的肝火上亢型CRF合并高血压患者90例作为研究对象,按照随机数字表法随机分为对照组和观察组,每组45例。对照组给予口服硝苯地平控释片治疗,观察组在对照组治疗基础上给予清肝解郁、健脾补肾汤治疗,每4周为1个疗程,均治疗3个疗程。比较治疗前后中医症状评分、收缩压(SBP)、舒张压(DBP)变化;比较2组临床疗效;比较治疗前后肾功能指标:尿素氮(BUN)、血肌酐(Scr)、24 h尿蛋白定量(24 hPRO);统计治疗期间2组不良反应发生情况。结果:治疗前观察组与对照组中医症状评分、SBP、DBP、BUN、Scr、24 hPRO比较,差异均无统计学意义(P>0.05),治疗后2组患者中医症状评分、SBP、DBP、BUN、Scr、24 hPRO均显著降低(P<0.05),观察组均低于对照组,差异有统计学意义(P<0.05);2组临床疗效比较,差异有统计学意义(P<0.05),且观察组总有效率显著高于对照组,差异有统计学意义(P<0.05);观察组和对照组不良反应发生率分别为2.22%和6.67%,2组比较差异无统计学意义(P>0.05)。结论:清肝解郁、健脾补肾法辅助治疗肝火上亢型CRF合并高血压疗效确切,可较好控制血压,并且可显著改善肾功能,减少不良反应发生情况。  相似文献   
86.
Objective: To determine whether packed red blood cell (PRBC) transfusion affects post-prandial superior mesenteric artery blood flow velocities (SMA BFVs) in very-low birth weight (VLBW) neonates and if so, at what time point after transfusion restoration of previous SMA BFV patterns occurs.

Design/Methods: VLBW pre-term neonates, older than 14 days and tolerating bolus enteral feedings administered every 3?h were enrolled in this prospective observational study. Pulsed Doppler ultrasound was used to measure pre- and post-prandial (at 45?min) time-averaged mean, peak and end diastolic velocities (TAMV, PSV, EDV) immediately before and after 15?ml/kg of PRBC transfusion was given over 3?h; patent ductus arteriosus (PDA) status was also evaluated. Subsequent pre- and post-prandial SMA BFVs were recorded 24 and 48?h after the transfusion.

Results: Pre- and post-prandial measurements were obtained for 21 out of 25 enrolled infants. Post-prandial SMA BFVs were attenuated during the feedings immediately after transfusion; at 24 and 48?h after transfusion, changes in post-prandial SMA BFVs were similar to those measured prior to transfusion; the presence of the PDA did not affect results.

Conclusions: PRBC transfusion blunted SMA BFV responses to feedings immediately after the transfusion with normalization observed 24?h post-transfusion.  相似文献   
87.
BackgroundDual antiplatelet therapy (DAPT) is the cornerstone treatment of acute myocardial infarction (AMI).ObjectiveThe present study aimed to investigate the efficacy and safety of triple antiplatelet therapy (TAPT) in elderly female patients with diabetes and ST segment elevation myocardial infarction (STEMI), who had undergone percutaneous coronary intervention (PCI).MethodsWe designed a randomized, single-blind study. Control group A (97 elderly male patients with diabetes and STEMI, whose CRUSADE scores were < 30) received aspirin, ticagrelor, and tirofiban. A total of 162 elderly female patients with diabetes and STEMI were randomly divided into two groups according to CRUSADE score. Group B (69 patients with CRUSADE score > 31) received aspirin and ticagrelor. Group C (93 patients with CRUSADE score < 30) received aspirin, ticagrelor and tirofiban. P values < 0.05 were considered statistically significant.ResultsCompared to the findings in group A, post-PCI Thrombolysis in Myocardial Infarction (TIMI) grade 3 blood flow and TIMI myocardial perfusion grade 3 were significantly less prevalent in group B (p < 0.05). When compared to groups A and C, the incidence of major adverse complications was significantly higher in group B (p < 0.05).ConclusionTAPT could effectively reduce the incidence of major complications in elderly female patients with diabetes and STEMI. However, close attention should be paid to hemorrhage in patients receiving TAPT. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)  相似文献   
88.
89.
应用拷贝数变异测序(copy number variation sequencing,CNV-seq)技术鉴别来源不明的胎儿标记染色体,明确其遗传物质的来源,并探讨此技术在产前诊断中的应用价值。讨论Pallister-Killian综合征(Pallister-Killian syndrome,PKS)的临床特征及遗传学特点,提高对此类罕见染色体疾病的认识。该病例因在妊娠中期超声发现胎儿异常而行羊水穿刺进行CNV-Seq检测,同时分析胎儿和父母的核型。羊水CNV-Seq结果示该样本12号染色体p13.33-p11.1处检测到拷贝数为3.5、片段大小为34.70 Mb的嵌合重复区域;羊水染色体核型结果为47,XY,+i(12)(p10)[58]/46,XX[42],综合上述结果考虑为PKS。通过结合超声结果,综合应用染色体G显带核型分析和CNV-seq技术能准确确认染色体异常片段来源,在产前有效诊断PKS患者。  相似文献   
90.
《Vaccine》2020,38(45):7118-7128
IntroductionToward the Global Vaccine Action Plan 2020 goal, almost 90% of countries have established a National Immunization Technical Advisory Group (NITAG). However, little is known about NITAG's contributions to governance.MethodsIn 2017–2018, a two-step, qualitative retrospective study was conducted. Jordan (JO), Argentina (AR), and South Africa (SA) were selected owing to government-financed NITAGs from middle-income countries (MICs), geographic diversity, and a vaccine introduction with NITAG support. Country case studies were developed, collecting data through desk review and face-to-face key informant interviews (KIIs) from Ministry of Health (MoH) and NITAG. Case studies were analyzed together, to assess governance applying the European Observatory on Health Systems and Policies framework focusing on transparency, accountability, participation, integrity, and policy capacity (TAPIC).ResultsDocument review and 53 KII (22 AR, 20 SA, 11 JO) showed NITAGs played a pivotal role as advisors promoting a culture of evidence-informed policies. NITAGs strengthened governance, although practices varied among countries. Meetings were conducted behind-closed-doors, participation restricted to members, only in one country agendas, and recommendations were public (AR). To increase participation, policy capacity, and transparency, countries considered adding experts in communications, advocacy, and economics. AR and SA contemplated including community members. NITAGs functioned autonomously from the government, with no established internal or external monitoring or supervision. NITAG meeting minutes allowed the review of integrity, adherence to terms of reference, standard operating procedures, and conflict of interest (CoI). For the most part, NITAGs abided by their mandates. Significant issues were related to the level of MoH support and oversight of CoI declaration and documentation.ConclusionsSystematically implementing governance approaches could improve processes, better tailor policies, and implementation. The long-term survival and resilience of NITAGs in these countries showed they play a significant role in strengthening governance. Lessons learned could be useful to those promoting country-driven evidence-informed decision-making.  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