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   298170篇
  免费   25085篇
  国内免费   17876篇
耳鼻咽喉   2644篇
儿科学   3752篇
妇产科学   5430篇
基础医学   32725篇
口腔科学   5275篇
临床医学   38646篇
内科学   45881篇
皮肤病学   3521篇
神经病学   15138篇
特种医学   10240篇
外国民族医学   108篇
外科学   31082篇
综合类   47590篇
现状与发展   65篇
一般理论   46篇
预防医学   20855篇
眼科学   7700篇
药学   30899篇
  246篇
中国医学   15322篇
肿瘤学   23966篇
  2024年   883篇
  2023年   3971篇
  2022年   10046篇
  2021年   13149篇
  2020年   9907篇
  2019年   8677篇
  2018年   9137篇
  2017年   8398篇
  2016年   7804篇
  2015年   12221篇
  2014年   15485篇
  2013年   14943篇
  2012年   22311篇
  2011年   24279篇
  2010年   16039篇
  2009年   13422篇
  2008年   16928篇
  2007年   17009篇
  2006年   16328篇
  2005年   15819篇
  2004年   11102篇
  2003年   9885篇
  2002年   8447篇
  2001年   7379篇
  2000年   7200篇
  1999年   7174篇
  1998年   4115篇
  1997年   4135篇
  1996年   3093篇
  1995年   2843篇
  1994年   2492篇
  1993年   1646篇
  1992年   2406篇
  1991年   2092篇
  1990年   1746篇
  1989年   1506篇
  1988年   1310篇
  1987年   1223篇
  1986年   970篇
  1985年   764篇
  1984年   497篇
  1983年   386篇
  1982年   232篇
  1981年   204篇
  1980年   194篇
  1979年   246篇
  1978年   143篇
  1977年   113篇
  1976年   98篇
  1974年   121篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Patients with mechanic ankle instability experience increased tibiotalar and subtalar joint laxity. However, in vivo joint kinematics in functional ankle instability (FAI) patients and lateral ankle sprain (LAS) copers, especially during dynamic activities, are poorly understood. Ten FAI patients, 10 LAS copers, and 10 healthy controls were included in this study. A dual fluoroscopic imaging system was used to analyze the tibiotalar and subtalar joint kinematics during stair descent. Five key poses of stair descent were analyzed. Kinematic data from six degrees of freedom were calculated utilizing a solid modeling software. The range of motion and joint positions in each degree of freedom were compared among the three groups. The tibiotalar joints of FAI patients and LAS copers were significantly more inverted than those of healthy controls during the foot strike (p = 0.016, = 0.264). The subtalar joints of FAI patients were significantly more anteriorly translated (pose 2, p = 0.003, = 0.352; pose 3, p < 0.001, = 0.454; pose 4, p = 0.004, = 0.334), inverted (pose 4, p = 0.027, = 0.234; pose 5,p = 0.034, = 0.221), and externally rotated (pose 4, p = 0.037, = 0.217; pose 5; p = 0.004, = 0.331) than those of healthy controls during the mid‐stance and the heel off. The FAI patients showed excessive tibiotalar inversion and subtalar joint hypermobility during stair descent. Meanwhile, the LAS copers maintained subtalar joint stability, and only showed excessive tibiotalar inversion in foot strike. These data provide insight into the mechanisms behind the development of FAI after initial LAS. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1860–1867, 2019  相似文献   
3.
4.
5.
目的:分析鼻塞式同步间歇正压通气(NIPPV)联合布地奈德雾化治疗ARDS(新生儿急性呼吸窘迫综合征)疾病的临床应用效果。方法:纳入病例是2017年5月—2019年11月收治的104例ARDS新生儿,随机平均分为两组。参照组52例采纳CPAP(持续气道正压通气通气)治疗,实验组52例采纳NIPPV+布地奈德雾化治疗,对比两组呼吸机通气时间、用氧时间、住院时间、血气指标以及并发症发生情况。结果:实验组呼吸机通气时间、用氧时间、住院时间均明显短于参照组,差异有统计学意义P<0.05;实验组治疗3 d后PaCO2明显低于参照组,实验组治疗3 d后PH以及PaO2明显高于参照组,差异有统计学意义P<0.05;实验组并发症发生率(3.85%,2/52)明显低于参照组(21.15%,11/52),差异有统计学意义P<0.05。结论:NIPPV+布地奈德雾化可有效缩短ARDS患者机械通气时间,改善血气指标,降低并发症发生率,值得借鉴。  相似文献   
6.

Context

Family caregivers constitute a critical component of the end-of-life care system with considerable cost to themselves. However, the joint association of terminally ill cancer patients' symptom distress and functional impairment with caregivers' subjective caregiving burden, quality of life (QOL), and depressive symptoms remains unknown.

Objectives/Methods

We used multivariate hierarchical linear modeling to simultaneously evaluate associations between five distinct patterns of conjoint symptom distress and functional impairment (symptom-functional states) and subjective caregiving burden, QOL, and depressive symptoms in a convenience sample of 215 family caregiver–patient dyads. Data were collected every 2 to 4 weeks over patients' last 6 months.

Results

Caregivers of patients in the worst symptom-functional states (States 3–5) reported worse subjective caregiving burden and depressive symptoms than those in the best two states, but the three outcomes did not differ between caregivers of patients in State 3 and States 4–5. Caregivers of patients in State 5 endured worse subjective caregiving burden and QOL than those in State 4. Caregivers of patients in State 4 suffered worse subjective caregiving burden and depressive symptoms but comparable QOL to those in State 2.

Conclusion

Patients' five distinct, conjoint symptom-functional states were significantly and differentially associated with their caregivers' worse subjective caregiving burden, QOL, and depressive symptoms while caring for patients over their last 6 months.  相似文献   
7.
Abstract

Background: This study aims to compare the effectiveness of inhaled prostacyclin or its analoguesversus nitric oxide (NO) in treating pulmonary hypertension (PH) after cardiac or pulmonary surgery remains unclear.

Methods: PubMed, Cochrane, and Embase databases were searched for literature published prior to December 2019 using the following keywords: inhaled, nitric oxide, prostacyclin, iloprost, treprostinil, epoprostenol, Tyvaso, flolan, and pulmonary hypertension. Randomized controlled trials and multiple-armed prospective studies that evaluated inhaled NO versus prostacyclin (or analogues) in patients for perioperative and/or postoperative PH after either cardiac or pulmonary surgery were included. Retrospective studies, reviews, letters, comments, editorials, and case reports were excluded.

Results: Seven studies with a total of 195 patients were included. No difference in the improvement of mean pulmonary arterial pressure (pooled difference in mean change= ?0.10, 95% CI: ?3.98 to 3.78, p?=?.959) or pulmonary vascular resistance (pooled standardized difference in mean change= ?0.27, 95% CI: ?0.60 to 0.05, p?=?.099) were found between the two treatments. Similarly, no difference was found in other outcomes between the two treatments or subgroup analysis.

Conclusions: Inhaled prostacyclin (or analogues) was comparable to inhaled NO in treating PH after cardiac or pulmonary surgery.
  • Key messages
  • This study compared the efficacy of inhaled prostacyclin or its analogues versus inhaled NO to treat PH after surgery. The two types of agent exhibited similar efficacy in managing MPAP, PVR, heart rate, and cardiac output was observed.

  • Inhaled prostacyclin may serve as an alternative treatment option for PH after cardiac or pulmonary surgery.

  相似文献   
8.
9.
严重脑损伤后17年的社会心理调整;由琥珀酸脱氢酶(SDHA)黄素蛋白(Fp)亚单位突变所致Leigh综合征;动脉瘤性蛛网膜下腔出血早期循环中的内皮细胞激活标记物水平:与脑缺血事件和预后的关系;CSF前列腺素E2水平与认知功能下降和阿尔茨海默病存活率的关系;变异型克罗伊茨费尔特-雅各布病患者的CSF磷酸-tau蛋白浓度升高:诊断和病理学意义。  相似文献   
10.
Finding appropriate soft-tissue to cover a wound located over the middle or distal portion of the foot can be challenging. A distally based sural fasciomusculocutaneous flap including the sural nerve and a midline cuff of the gastrocnemius muscle can be used for this purpose. This flap is designed on the proximal third of the posterior calf and is nourished in a retrograde manner by the lower peroneal septocutaneous perforators, through the vascular axis of the sural nerve to the musculocutaneous perforators of the gastrocnemius muscle. Between October of 2002 and January of 2004, this flap was applied in nine individuals, including four diabetic patients. The skin defects all resulted from trauma, osteomyelitis or chronic ulcer, and combined with bone or tendon exposure. One flap developed distal necrosis. The other flaps survived fully and provided good contour. In our series, diabetes mellitus seemed not to compromise the vascularity of the flap. The distally based sural fasciomusculocutaneous flap is very useful for lower limb reconstruction, particularly for the foot, because of its long vascular pedicle and the availability of the skin portion of the proximal calf based on direct branches between the musculocutaneous perforators and the neurovascular axis of the sural nerve. This is an important variant of the sural neurocutaneous flap and it appears to be a good alternative to free flaps for resurfacing the foot.  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