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   11628篇
  免费   763篇
  国内免费   62篇
耳鼻咽喉   106篇
儿科学   315篇
妇产科学   229篇
基础医学   1704篇
口腔科学   256篇
临床医学   1007篇
内科学   2656篇
皮肤病学   430篇
神经病学   1164篇
特种医学   293篇
外科学   997篇
综合类   60篇
现状与发展   1篇
一般理论   3篇
预防医学   1366篇
眼科学   222篇
药学   810篇
中国医学   53篇
肿瘤学   781篇
  2023年   132篇
  2022年   233篇
  2021年   508篇
  2020年   260篇
  2019年   432篇
  2018年   528篇
  2017年   320篇
  2016年   305篇
  2015年   379篇
  2014年   535篇
  2013年   647篇
  2012年   1003篇
  2011年   964篇
  2010年   555篇
  2009年   454篇
  2008年   730篇
  2007年   726篇
  2006年   620篇
  2005年   670篇
  2004年   563篇
  2003年   520篇
  2002年   466篇
  2001年   85篇
  2000年   51篇
  1999年   89篇
  1998年   77篇
  1997年   64篇
  1996年   61篇
  1995年   52篇
  1994年   31篇
  1993年   40篇
  1992年   37篇
  1991年   33篇
  1990年   23篇
  1988年   17篇
  1987年   19篇
  1985年   8篇
  1984年   15篇
  1983年   15篇
  1982年   7篇
  1981年   8篇
  1980年   7篇
  1979年   8篇
  1978年   8篇
  1977年   8篇
  1974年   8篇
  1972年   7篇
  1968年   7篇
  1966年   8篇
  1965年   7篇
排序方式: 共有10000条查询结果,搜索用时 835 毫秒
121.
ObjectivesThis study measured the degree of conversion (DC), sorption, solubility and microhardness of methacrylate (Filtek Z250 and Filtek Z350XT) and silorane-based composites (Filtek P90).MethodsDC was measured using near infrared spectroscopy immediately and 24 h after the photoactivation. Sorption and solubility measurements were performed after 24 h, 4 weeks and 12 weeks of storage in water. Knoop microhardness was measured after 24 h and after thermal cycling. The data were statistically analyzed using ANOVA followed by Tukey's, Tamhane or paired t-tests (α = 0.05).ResultsThe DC for P90 (37.22 ± 1.46) was significantly lower than the Z250 (71.44 ± 1.66) and Z350 (71.76 ± 2.84). Water sorption was highest in the Z250 and lowest in the P90. All the tested composites exhibited similar values after 24 h of immersion, and no significant differences were observed. No significant differences were observed between the solubilities of the P90 composite (12 weeks) and the Z250 or Z350 composites (4 weeks). KHN values were less elevated for the P90 composite and similar for the Z250 and Z350 composites. An effect of thermal cycling on KHN values was observed for all the composites (p < 0.001).ConclusionsSilorane produced the lowest DC and KHN values and exhibited lower water sorption and solubility compared to methacrylate-based composites. These differences suggest that silorane composites exhibit better hydrolytic stability after 3 months of water immersion compared to conventional methacrylate-based composites.Clinical significanceSilorane had higher hydrolytic stability after 3 months of water immersion than the methacrylate-based resins, despite the lower values of DC and KHN recorded.  相似文献   
122.
123.
Introduction and objectivesLaryngeal electromyography, together with clinical evaluation, is a valuable tool in voice disorder management. It assesses the integrity of laryngeal nerves and muscles, contributing to the diagnosis of many diseases, especially laryngeal movement disorders. Our purpose was to describe the experience of the first Spanish series with laryngeal electromyography in evaluating voice disorders.MethodsA prospective study was designed to evaluate laryngeal movement disorders with laryngeal electromyography. Both the cricothyroid and thyroarytenoid muscles were tested routinely and, in some cases, the posterior cricoarytenoid muscle. The laryngeal electromyography technique and result interpretation were performed by a laryngologist and a neurophysiologist.ResultsWe included 110 patients, with the most common symptom being dysphonia. Laryngeal electromyography was performed in 85% of cases. Primary diagnosis before electromyography was laryngeal immobility. Positive predictive value for diagnosis in cases of paralysis was 88%.ConclusionsLaryngeal electromyography is a useful adjunct, together with clinical evaluation, for diagnosis and management of motion abnormalities in the larynx in patients who present with dysphonia.  相似文献   
124.
Intra-abdominal infections represent a large and wide group of diseases which include intra- and retro-peritoneal infections. Some of them could be defined as uncomplicated, where the infectious process is limited to the organ or tissue of origin (appendicitis, diverticulitis, cholecystitis…). Complications occur when the infection spreads to the peritoneum, triggering localised peritonitis and abdominal abscesses.  相似文献   
125.
Over the past 10 years Spain has become an important immigrant receiver country as the proximity with Africa and the cultural facilities with Latino-American countries have made of Spain a very attractive place to settle down for immigrants. From 1st January 2007 to 31st December 2007, all the pediatric patients visits (0–14 years old) seen in the units of the Dermatology Section of the University General Hospital of Alicante (Spain) were prospectively recorded. During the study period 3,108 visits were recorded. Of these, 447 (14.3 %) were generated by immigrant children, 243 (54.3 %) being episodes requested by 167 Latin American patients. Latin children consulted mainly in the outpatient clinic, like Spanish children. The most frequent type of dermatoses in these patients was eczema/atopic dermatitis. Infectious dermatitis showed no differences between them and Spaniards, but scabies was six times more frequent in the formers.  相似文献   
126.
127.
128.
129.
Acanthamoeba is an opportunistic pathogen in humans, whose infections most commonly manifest as Acanthamoeba keratitis or, more rarely, granulomatous amoebic encephalitis. Although there are many therapeutic options for the treatment of Acanthamoeba, they are generally lengthy and/or have limited efficacy. Therefore, there is a requirement for the identification, validation, and development of novel therapeutic targets against these pathogens. Recently, RNA interference (RNAi) has been widely used for these validation purposes and has proven to be a powerful tool for Acanthamoeba therapeutics. Ergosterol is one of the major sterols in the membrane of Acanthamoeba. 3-Hydroxy-3-methylglutaryl–coenzyme A (HMG-CoA) reductase is an enzyme that catalyzes the conversion of HMG-CoA to mevalonate, one of the precursors for the production of cholesterol in humans and ergosterol in plants, fungi, and protozoa. Statins are compounds which inhibit this enzyme and so are promising as chemotherapeutics. In order to validate whether this enzyme could be an interesting therapeutic target in Acanthamoeba, small interfering RNAs (siRNAs) against HMG-CoA were developed and used to evaluate the effects induced by the inhibition of Acanthamoeba HMG-CoA. It was found that HMG-CoA is a potential drug target in these pathogenic free-living amoebae, and various statins were evaluated in vitro against three clinical strains of Acanthamoeba by using a colorimetric assay, showing important activities against the tested strains. We conclude that the targeting of HMG-CoA and Acanthamoeba treatment using statins is a novel powerful treatment option against Acanthamoeba species in human disease.  相似文献   
130.
ObjectiveTo determine how many dispensary drugs should be in the safety stock in a tertiary hospital in accordance with the risk level and the number of days that the hospital is able to withstand a stockout.MethodsWe statistically analysed the infliximab order recorded over a period of 120 days. This drug is relevant for this study as it is costly and is immediately supplied to the clinic. Using the data records for purchasing and dispensing in our department, we created a table to compare the level of risk assumed with the number of units in stock and the number of days that the safety stock should last. In addition, we calculated how much stock there should be in accordance with different heuristic rules used by pharmacy departments.ResultsIn the period being studied, the daily order was 11.4 ± 14.8 units of infliximab. Using the methodology proposed, we discovered that there should be 79 units in the safety stock. Other hospital rules determine values of 47 and 119 units.ConclusionsThe method proposed allows us to discover the risk level that is assumed when selecting the safety stock. Therefore, we are able to design a safety stock policy consistent with the risk level adopted. Under certain assumptions the safety stock quota provided by this method could be reduced. Lastly, there is a notable difference between the safety stock values suggested by different rules, as it has been shown in this article.  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