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   2587篇
  免费   364篇
  国内免费   77篇
耳鼻咽喉   10篇
儿科学   16篇
妇产科学   2篇
基础医学   75篇
口腔科学   215篇
临床医学   211篇
内科学   144篇
皮肤病学   51篇
神经病学   25篇
特种医学   32篇
外科学   59篇
综合类   289篇
预防医学   102篇
眼科学   1072篇
药学   408篇
  3篇
中国医学   306篇
肿瘤学   8篇
  2024年   14篇
  2023年   77篇
  2022年   113篇
  2021年   182篇
  2020年   120篇
  2019年   127篇
  2018年   147篇
  2017年   170篇
  2016年   157篇
  2015年   130篇
  2014年   171篇
  2013年   251篇
  2012年   159篇
  2011年   147篇
  2010年   136篇
  2009年   125篇
  2008年   129篇
  2007年   111篇
  2006年   84篇
  2005年   71篇
  2004年   58篇
  2003年   42篇
  2002年   57篇
  2001年   44篇
  2000年   31篇
  1999年   24篇
  1998年   19篇
  1997年   17篇
  1996年   21篇
  1995年   9篇
  1994年   14篇
  1993年   5篇
  1992年   9篇
  1991年   5篇
  1990年   6篇
  1989年   9篇
  1988年   6篇
  1987年   7篇
  1986年   4篇
  1985年   2篇
  1984年   3篇
  1983年   2篇
  1982年   5篇
  1981年   4篇
  1980年   1篇
  1978年   1篇
  1977年   2篇
排序方式: 共有3028条查询结果,搜索用时 31 毫秒
51.
目的 采用亲水凝胶骨架材料制备盐酸多奈哌齐缓释片,并对其质量进行评价。方法 采用亲水凝胶骨架材料HPMC K100LV和K4M联用通过干法制粒工艺制备盐酸多奈哌齐缓释片,以溶出曲线相似性f2值作为评价指标,通过正交设计进行处方优化,用高效液相色谱法进行含量和杂质检测,通过加速和长期试验考察片剂稳定性。结果 以该方法制备的盐酸多奈哌齐缓释片质量稳定,具有与原研制剂一致的溶出特征。结论 以该方法制备盐酸多奈哌齐缓释片具有可行性。  相似文献   
52.
设置了5个氮素浓度梯度(N0、N1、N2、N3、N4)、3个PEG(P0、P1、P2)浓度梯度以及2个CO2浓度(370±50 μmol·mol-1; 700±50 μmol·mol-1)水平的盆栽试验,探究了小麦幼苗生长、物质积累与分配以及植株水分条件的变化规律。结果表明:小麦幼苗株高、地上部干重、根干重、生物量以及叶水势的最大值以及高浓度CO2的最大刺激作用均出现在处理N1P0; 而根长和根冠比的最大值分别出现在处理N0P0和N1P2,高浓度CO2的最大刺激值也分别出现在处理N0P0和N1P2; 适宜养分条件下,高浓度CO2能够最大限度地促进小麦幼苗的生长,同时高浓度CO2通过提高小麦幼苗叶水势,一定程度上缓解了低浓度PEG胁迫的不利影响。因此,未来CO2浓度升高将对水肥条件好的小麦产生促进作用,可缓解轻度水分不足的不利影响,而对严重干旱胁迫下小麦的生长作用不明显。  相似文献   
53.
目的 总结近5年针灸治疗干眼症的临床研究进展,并提出存在问题与研究展望.方法 检索2008年1月-2013年6月发表的针灸治疗干眼症的临床研究文献,从临床疗效、临床操作、诊疗标准及作用机制角度进行探讨.结果 针灸治疗干眼症以眼周局部取穴为主,常用穴位有睛明、攒竹、太阳等,配穴以局部和远端取穴相结合为主,但诊疗标准缺乏统一,机制研究较少,有待进一步完善.结论 针灸通过刺激神经兴奋,促进泪腺、睑板腺主动分泌泪液,双向调节性激素水平等环节起到缓解眼部症状的功效.  相似文献   
54.
ABSTRACT

Objective

This randomized, single-center clinical trial aimed to compare the efficacy of superficial dry needling (SDN) and deep dry needling (DDN) in patients with myofascial temporomandibular disorder (MTMD) related to the masseter muscle.Methods: Forty patients showing MTMD with trigger points in the masseter muscle were randomly assigned to groups. Dry needling of the masseter muscle was performed once per week for three weeks. Pressure pain threshold (PPT) measurements, visual analog scale scores, and maximal jaw opening were assessed.Results: Both patient groups showed significant pain reduction, but the SDN group showed significantly better pain reduction. The PPT measurements obtained in the follow-up examinations at three and six weeks were significantly better than the values in SDN and DDN groups.Discussion: SDN showed better pain-reduction efficacy in patients with MTMD. Further research with a larger size sample and a longer follow-up period will help elucidate the benefits of SDN.  相似文献   
55.
Conclusion: A set of methods for evaluating changes in salivary secretion and sense of taste following cochlear implantation (CI) was applied and tested. No association between implantation and objectively assessed sense of taste was found. However, a statistically significant decrease in non-stimulated salivary flow on the day after surgery was found. Objectives: To develop and test a research method describing the course of changes in salivary secretion and sense of taste following CI. Methods: This was a longitudinal study examining 13 patients undergoing CI at Odense University Hospital in 2012. Questionnaires, sialometry and gustatory testing were applied. Results: A general postoperative decrease in salivary secretion could not be found. However, a 29.9% mean reduction in non-stimulated salivary flow was observed when looking specifically at the visit the day after surgery (p = 0.001). When adjusting for perioperative administration of glycopyrrolate (p < 0.001) and atropine (p = 0.178), the former was highly associated with a 69.7% mean decrease in non-stimulated salivary flow at the visit the day after surgery. The third examination was still, independent of glycopyrrolate administration, borderline significantly associated with a 14.5% mean decrease (p = 0.054). We did not find any significant decrease in sense of taste following implantation.  相似文献   
56.
ABSTRACT

Objective: The purpose of this study was to examine the within and between-group effects of segmental and distal dry needling (DN) without needle manipulation to a semi-standardized non-thrust manipulation (NTM) targeting the symptomatic spinal level for patients with non-specific low back pain (NSLBP).

Methods: Sixty-five patients with NSLBP were randomized to receive either DN (n = 30) or NTM (n = 35) for six sessions over 3 weeks. Outcomes collected included the oswestry disability index (ODI), patient specific functional scale (PSFS), numeric pain rating scale (NPRS), and pain pressure thresholds (PPT). At discharge, patients perceived recovery was assessed.

Results: A two-way mixed model ANOVA demonstrated that there was no group*time interaction for PSFS (= 0.26), ODI (= 0.57), NPRS (= 0.69), and PPT (= 0.51). There was significant within group effects for PSFS (3.1 [2.4, 3.8], = 0.018), ODI (14.5% [10.0%, 19.0%], = 0.015), NPRS (2.2 [1.5, 2.8], = 0.009), but not for PPT (3.3 [0.5, 6.0], = 0.20).

Discussion: The between-group effects were neither clinically nor statistically significant. The within group effects were both significant and exceeded the reported minimum clinically important differences for the outcomes tools except the PPT. DN and NTM produced comparable outcomes in this sample of patients with NSLBP.

Level of evidence: 1b  相似文献   
57.
Dry foam formulation technology is alternative approach to enhance dissolution of the drug. Sildenafil citrate was suspended in sodium dodecyl sulfate solution and adding a mixture of maltodextrin and mannitol as diluent to form a paste. Sildenafil citrate paste was passed through a nozzle spray bottle to obtain smooth foam. The homogeneous foam was dried in a vacuum oven and sieved to obtain dry foam granules. The granules were mixed with croscarmellose sodium, magnesium stearate and compressed into tablet. All formulations were evaluated for their physicochemical properties and dissolution profiles. All the tested excipients were compatible with sildenafil citrate by both differential scanning calorimetry (DSC) and infrared (IR) analysis. There are no X-ray diffraction (XRD) peaks representing crystals of sildenafil citrate observed form dry foam formulations. The hardness of tablets was about 5?kg, friability test <1% with a disintegration time <5?min. The sildenafil citrate dry foam tablet had higher dissolution rate in 0.1 N HCl in comparison with commercial sildenafil citrate tablet, sildenafil citrate prepared by direct compression and wet granulation method. Sildenafil citrate dry foam tablet with the high-level composition of surfactant, water and diluent showed enhanced dissolution rate than that of the lower-level composition of these excipients. This formulation was stable under accelerated conditions for at least 6 months.  相似文献   
58.
目的比较干、湿化学法对乳糜状态标本部分生化指标检测结果的影响。方法收集50例乳糜样标本,分别用日立7180和VITROS 350对丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、葡萄糖(GLU)、肌酐(Cr)、总蛋白(TP)五项指标进行检测。结果 GLU、Cr、TP用两种方法测定结果差异均无统计学意义(P>0.05);而ALT、AST结果比较,两种方法间差异有统计学意义(P<0.05),但二者结果具有良好的相关关系。结论定期对不同生化分析仪的测定结果进行比对和校准,是保证检验结果准确性的一种可靠方法。  相似文献   
59.
Introduction: Dry eye disease (DED) is a common, age-related ocular condition that in its mildest forms causes bothersome symptoms of ocular discomfort, fatigue, and visual disturbance that interfere with quality of life and in its more severe forms causes chronic pain and fluctuating vision. Though it is highly prevalent and costs billions of dollars to manage, current treatments have largely been inadequate, making it a frustrating condition, both for physicians and patients alike.

Areas covered: This article will cover the recently discovered pathophysiology of DED that has prompted investigators to explore new molecules that target the core mechanisms that drive DED. These include anti-inflammatory/immune-modulatory drugs, secretagogues, lubricant, hormones, and autologous serum. Their potential mechanism of action and data from recent trials on efficacy/safety will be reviewed.

Expert opinion: The emerging drugs have a vast range of putative mechanisms of action that may not only provide symptomatic relief but may potentially break the vicious cycle of DED and provide long-lasting cure. Current and future research may change our perspective on DED and redefine its treatment algorithms.  相似文献   
60.
Abstract

Dry foam technology reveals the opportunity to improve the dissolution behavior of poorly soluble drugs tending to agglomeration due to micronization. In this study, the impact of fillers on the manufacturability, the properties of dry foams and granules as well as the dissolution kinetics of dry foam tablets was investigated using fenofibrate as a model compound. Different maltodextrins and dried glucose syrups, a maltodextrin–phosphatidylcholine complex, isomalt and a 1:1 mixture of mannitol/glucose syrup were used as filler. Within the group of maltodextrins and glucose syrups, the influences of dextrose equivalent (DE), particle morphology and botanical source of starch were investigated. Comparable macroscopic foam structures were obtained with maltodextrins and glucose syrups whereas different foam morphologies were obtained for the other fillers tested. Regarding the maltodextrins and glucose syrups, different physicochemical and particle properties had a minor impact on granule characteristics and tablet dissolution. Using the maltodextrin–phosphatidylcholine complex resulted in a low specific surface area of the granules and a slow tablet dissolution caused by a slow disintegration. In contrast, a high specific surface area and a fast release were obtained with isomalt and glucose syrup/mannitol mixture indicating that high soluble low molecular weight fillers enable the development of fast dissolving dry foam tablets.  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