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   3663篇
  免费   167篇
  国内免费   61篇
耳鼻咽喉   36篇
儿科学   88篇
妇产科学   60篇
基础医学   291篇
口腔科学   62篇
临床医学   317篇
内科学   334篇
皮肤病学   60篇
神经病学   391篇
特种医学   180篇
外科学   636篇
综合类   417篇
预防医学   315篇
眼科学   29篇
药学   467篇
  1篇
中国医学   88篇
肿瘤学   119篇
  2023年   63篇
  2022年   151篇
  2021年   157篇
  2020年   133篇
  2019年   154篇
  2018年   155篇
  2017年   113篇
  2016年   111篇
  2015年   121篇
  2014年   200篇
  2013年   220篇
  2012年   178篇
  2011年   192篇
  2010年   165篇
  2009年   181篇
  2008年   180篇
  2007年   141篇
  2006年   135篇
  2005年   119篇
  2004年   115篇
  2003年   107篇
  2002年   75篇
  2001年   63篇
  2000年   49篇
  1999年   53篇
  1998年   55篇
  1997年   33篇
  1996年   56篇
  1995年   30篇
  1994年   38篇
  1993年   29篇
  1992年   28篇
  1991年   30篇
  1990年   23篇
  1989年   23篇
  1988年   13篇
  1987年   11篇
  1986年   15篇
  1985年   23篇
  1984年   25篇
  1983年   9篇
  1982年   16篇
  1981年   14篇
  1980年   17篇
  1979年   10篇
  1978年   9篇
  1977年   7篇
  1976年   9篇
  1973年   7篇
  1972年   6篇
排序方式: 共有3891条查询结果,搜索用时 15 毫秒
91.
Myotonic dystrophy type‐1 (Steinert disease) is an autosomal dominant, progressive multisystem disease in which myotonic crisis can be triggered by several factors including pain, emotional stress, hypothermia, shivering, and mechanical or electrical stimulation. In this report, dexmedetomidine‐based general anesthesia, in combination with a thoracic epidural for laparoscopic cholecystectomy in a patient with Steinert disease, is presented. An Aintree intubation catheter with the guidance of a fiberoptic bronchoscope was used for intubation to avoid laryngoscopy. Prolonged anesthetic effects of propofol were reversed, and recovery from anesthesia was accelerated using an intravenous infusion of theophylline.  相似文献   
92.
In this study, biocompatible double layered beads consisting of pectin core and alginate shell were prepared through a single step manufacturing process based on prilling apparatus equipped with co-axial nozzles. The core was loaded with piroxicam (PRX) as model non-steroidal anti-inflammatory drug (NSAID). Morphology, size distribution and shape of the double layered beads varied depending on the operative conditions and polymer concentrations. Co-axial nozzles size, applied vibration frequency, gelling conditions and, mainly, polymers mass ratio were identified as critical variables. Particularly, the relative viscosity of polymeric feed solutions inside the nozzle was the key parameter to obtain homogeneous and well-formed coated particles. The produced beads were investigated for the release kinetic in different media. Once PRX was encapsulated within the pectin core, a controlled release pattern was observed. Particularly, beads produced with 4:1 core/shell ratio (F4) released less than 30% of PRX in simulated gastric fluid (SGF) while total liberation of the drug was achieved during the next 3 h in simulated intestinal fluid (SIF). More interesting, F4 tested in SIF was able to release drug in a delayed and sustained manner at established time points (2h_8.2%, 3h_32.2%, 4h_70.1% and 5h_about 100%). Based on the above results, co-axial prilling approach is expected to provide success in manufacturing systems with delayed drug release profiles. Such systems may be potentially useful in targeting diseases which are affected by the circadian rhythm, such as chronic inflammation.  相似文献   
93.
IntroductionChronic pain is a debilitating condition that affects many people. Currently, there is no single treatment known to cure or assure relief from chronic pain. Accordingly, the management of patients’ discomfort is an integral part of treating chronic pain. Such treatment, however, is not effective for many patients. We investigated whether mirthful laughter provided by comic relief can influence pain tolerance and muscle soreness in young healthy participants.MethodsForty participants underwent a randomized controlled cross-over designed experiment. Each participant was exposed to a comedy video eliciting mirthful laughter and an uninteresting documentary. Delayed onset muscle soreness was induced in one leg at a time by eccentric exercise. Pain tolerance was tested using blunt force application and assessed subjectively using a visual analog scale.ResultsWatching the comedy video elicited a significantly greater irregular breathing pattern compared with watching the documentary video (p < 0.001). After watching the comedy, the participants’ positive affect was increased (Δ2 ± 1) while it was largely decreased (Δ-11 ± 2) after watching the documentary video (p < 0.001). Pain tolerance was decreased by 17 ± 5 N after viewing the documentary video (p < 0.001), but did not change significantly after watching the comedy.ConclusionsThirty minutes of watching a comedy eliciting laughter favorably influenced pain tolerance in healthy humans.Clinical trial no.#NCT02896075.  相似文献   
94.
95.
96.
目的:探究中周部加光镜片联合调节训练延缓近视发展的临床疗效。方法:选取2011年6月-2012年6月门诊复查检查确诊为近视的60例患者,随机分为治疗组和对照组,每组各30例。治疗组采用中周部加光镜片联合调节训练延缓近视的发展,对照组则采用常规治疗方法调节训练延缓近视的发展。结果:治疗组患者的近视延缓明显要优于对照组,两组差异有统计学意义(P〈0.05)。结论:中周部加光镜片联合调节训练延缓近视发展具有较好的临床疗效,值得推广应用。  相似文献   
97.

Introduction

Knowledge about the functional consequences of lower limb long bone fractures is helpful to inform patients, clinicians and employers about their recovery process and prognosis. This study aims to describe the epidemiology and health outcomes of femoral and tibial shaft fractures treated at two level I trauma centres, by comparing the differences between patients with delayed union or nonunion and patients with union.

Patients and methods

An analysis of registry data over two years, supplemented with medical record review, was conducted. Fracture healing was retrospectively assessed by clinical and radiological evidence of union, and the need for surgical intervention. SF-12 scores, and work and pain status were prospectively recorded at six and twelve months post injury.

Results

285 fractures progressed to union and 138 fractures developed delayed union or nonunion. There was a significant difference between the two cohorts with regards to the mechanism of injury, association with multi-trauma, open fractures, grade of Gustilo classification, patient fund source, smoking status and presence of comorbidities. The SF-12 physical component score was less than 50 at both six and twelve months with improvement in the union group, but not in the delayed union or nonunion group. 72% of patients with union had returned to work at one year, but 54% continued to have pain. The difference compared to patients with delayed union or nonunion was significant.

Discussion

Even patients whose fractures unite in the expectant time-frame will have residual physical disability. Patients with delayed union or nonunion have still poorer outcomes, including ongoing problems with returning to work and pain. It is important to educate patients about their injury so that they have realistic expectations. This is particularly relevant given that the patients most likely to sustain femoral or tibial shaft fractures are working-age healthy adults, and up to a third of fractures may develop delayed union or nonunion.

Conclusion

Despite modern treatment, the patient-reported outcomes of lower limb long bone shaft fractures do not return to normal at one year. Patients with delayed union or nonunion can expect poorer outcomes.  相似文献   
98.

Background

The role of heme oxygenase-1 (HO-1) in the cardioprotection induced by delayed remote ischemic preconditioning (DRIPC) has not been investigated. Therefore, this study was designed to investigate whether HO-1 is involved in DRIPC-mediated cardioprotection in an isolated perfused rat heart model.

Materials and methods

Isolated rat hearts were subjected to 30 min ischemia followed by 60 min reperfusion. DRIPC (four cycles 5-min occlusion and 5-min reflow at the unilateral hind limb once per day for 1, 2, or 3 d before heart isolation, abbreviated as D1RIPC, D2RIPC, or D3RIPC respectively). Infarct size, myocardial troponin levels, and heart function were measured. The protein and messenger RNA levels of HO-1 were determined.

Results

DRIPC facilitated postischemic cardiac functional recovery and decreased cardiac enzyme release. The infarct size-limiting effect of DRIPC was more pronounced in the D3RIPC group (10.22 ± 2.57%) than the D1RIPC group (22.34 ± 4.02%, P < 0.001) or the D2RIPC group (14.60 ± 3.13%, P = 0.034). These effects in the D1RIPC group could be blocked by Zinc Protoporphyrin IX (ZnPP) (an HO-1 specific inhibitor). DRIPC-mediated cardioprotection was associated with enhanced HO-1 protein expression (D1RIPC, 0.11 ± 0.03; versus 0.15 ± 0.06 in the D2RIPC group, P = 0.06; versus 0.20 ± 0.04 in the D3RIPC group, P = 0.04) and messenger RNA levels of HO-1 expression.

Conclusions

Our findings suggest that HO-1 is involved in the cardioprotection induced by DRIPC, and that increase in the number of preconditioning stimuli may enhance cardioprotective effects accompanied with increased HO-1 level.  相似文献   
99.
Disorders of the gastrointestinal (GI) tract are common and distressing nonmotor symptoms of Parkinson's disease (PD) that can adversely affect levodopa absorption and lead to OFF periods, also known as motor fluctuations. Gastroparesis, which is primarily defined as delayed gastric emptying (DGE), and Helicobacter pylori infection, which is present with increased frequency in PD, are among the most common and important GI disorders reported in PD that may impair oral levodopa absorption and increase OFF time. Symptoms of gastroparesis include nausea, vomiting, postprandial bloating, fullness, early satiety, abdominal pain, and weight loss. DGE has been reported in a substantial fraction of individuals with PD. Symptoms of H. pylori infection include gastritis and peptic ulcers. Studies have found that DGE and H. pylori infection are correlated with delayed peak levodopa plasma levels and increased incidence of motor fluctuations.Therapeutic strategies devised to minimize the potential that gastric complications will impair oral levodopa absorption and efficacy in PD patients include treatments that circumvent the GI tract, such as apomorphine injection, levodopa intestinal gel delivery, levodopa inhalation powder, and deep brain stimulation. Other strategies aim at improving gastric emptying in PD patients, primarily including prokinetic agents.  相似文献   
100.
从标准化战略、法律法规、管理机制、运行监督及保障机制和具体的标准目录等方面,总结欧盟医疗器械标准体系的发展现状,以期对我国医疗器械标准研究有所启示。  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