全文获取类型
收费全文 | 20636篇 |
免费 | 1612篇 |
国内免费 | 59篇 |
专业分类
耳鼻咽喉 | 281篇 |
儿科学 | 669篇 |
妇产科学 | 487篇 |
基础医学 | 3002篇 |
口腔科学 | 362篇 |
临床医学 | 1975篇 |
内科学 | 3910篇 |
皮肤病学 | 305篇 |
神经病学 | 2038篇 |
特种医学 | 749篇 |
外科学 | 2769篇 |
综合类 | 628篇 |
现状与发展 | 1篇 |
一般理论 | 27篇 |
预防医学 | 1701篇 |
眼科学 | 568篇 |
药学 | 1394篇 |
中国医学 | 40篇 |
肿瘤学 | 1401篇 |
出版年
2022年 | 252篇 |
2021年 | 406篇 |
2020年 | 237篇 |
2019年 | 373篇 |
2018年 | 455篇 |
2017年 | 285篇 |
2016年 | 380篇 |
2015年 | 425篇 |
2014年 | 542篇 |
2013年 | 860篇 |
2012年 | 1211篇 |
2011年 | 1154篇 |
2010年 | 696篇 |
2009年 | 659篇 |
2008年 | 1074篇 |
2007年 | 1082篇 |
2006年 | 983篇 |
2005年 | 1062篇 |
2004年 | 1085篇 |
2003年 | 997篇 |
2002年 | 903篇 |
2001年 | 371篇 |
2000年 | 386篇 |
1999年 | 363篇 |
1998年 | 232篇 |
1997年 | 178篇 |
1996年 | 180篇 |
1995年 | 190篇 |
1994年 | 127篇 |
1993年 | 165篇 |
1992年 | 275篇 |
1991年 | 268篇 |
1990年 | 271篇 |
1989年 | 286篇 |
1988年 | 248篇 |
1987年 | 240篇 |
1986年 | 248篇 |
1985年 | 253篇 |
1984年 | 208篇 |
1983年 | 155篇 |
1982年 | 163篇 |
1981年 | 171篇 |
1980年 | 142篇 |
1979年 | 132篇 |
1978年 | 113篇 |
1977年 | 111篇 |
1976年 | 128篇 |
1975年 | 112篇 |
1974年 | 144篇 |
1973年 | 103篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
941.
942.
Current perspectives on the diagnosis and treatment of functional esophageal disorders 总被引:2,自引:0,他引:2
Among the functional gastrointestinal disorders, functional disorders of the esophagus are second in prevalence only to irritable
bowel syndrome. Progress has been made in recent years in our understanding of the pathophysiology of functional esophageal
disorders. In this review we focus on recent advances in their diagnosis and treatment. Additionally, we critically appraise
the current understanding of the various clinical aspects of each esophageal disorder. Finally, we highlight unanswered questions
and areas of controversy. 相似文献
943.
944.
Rogers RS 《Dermatologic Clinics》2003,21(1):49-61
The conditions of complex aphthosis, EM, MMP, and the VVG variant of erosive oral LP may be confused by clinicians who refer patients for diagnosis and management of BD (Table 8). The mucocutaneous presentations or the presence of complex aphthosis, the hallmark of BD, can be confusing and lead to the referral of the patient for a diagnosis of BD. The astute clinician evaluating patients for BD considers pseudo-BD in the differential diagnosis of the mucocutaneous manifestations of BD. 相似文献
945.
Burning mouth syndrome 总被引:1,自引:0,他引:1
Burning mouth syndrome is the occurrence of oral pain in a patient with a normal oral mucosal examination. It can be caused by both organic and psychologic or psychiatric factors, which can be broken down into local, systemic. psychologic or psychiatric, and idiopathic causes. The most frequently associated conditions are psychiatric (depression, anxiety, or cancerphobia); xerostomia; nutritional deficiency; allergic contact dermatitis; candidiasis; denture-related pain: and parafunctional behavior. Multiple different factors contributing to the oral pain are common, and a systematic approach to the evaluation is important. Identification of correctable causes of BMS should be emphasized and psychiatric causes should not be invoked without thorough evaluation of the patient. A directed history and careful oral examination must be completed to exclude local diseases and identify clues to potential causes. Assessment of medications, psychiatric history and background, and selected laboratory and patch tests may help identify the etiologies of these symptoms. Treatment should be tailored to each patient and may best be managed in a multidisciplinary approach with input from dermatologists, dentists, psychiatrists. otorhinolaryngologists, and primary care providers. A thoughtful and structured evaluation of the patient with BMS has been associated with improvement in about 70% of patients. The remaining patients may benefit from empiric therapy with a chronic pain protocol and continued supportive interactions. 相似文献
946.
A systematic review of research evidence is an efficient approach to integrating existing information, invariably a multiplicity of published articles, with a view to establishing whether the scientific findings are consistent. If so, it may be possible to draw conclusions and make recommendations about treatment regimens or observed effects which have greater credence than those obtained from individual studies. The systematic review relies on a specified checklist which determines which articles should be included in the review, and how each should be critically appraised to provide relevant information relating to the focus of the review. 相似文献
947.
Statistics can be defined as the methods used to assimilate data, so that guidance can be given, and conclusions drawn, in situations which involve uncertainty. In particular, statistical inference is concerned with drawing conclusions about particular aspects of a population when that population cannot be studied in full. Uncertainty arises here because the totality of the information is not available. Instead, to make inferences about the population, it is necessary to rely on a sample of data which is selected from the population; this sample data may be augmented, in certain circumstances, by auxiliary information which is obtained independently of the sample data. Clearly, uncertainty lies at the heart of statistics and statistical inference. This uncertainty is measured by a probability which therefore forms the crux of statistics and must be properly understood in order to interpret a statistical analysis. 相似文献
948.
BACKGROUND: Antimicrobial agents are sometimes used as adjuncts for the treatment of aggressive and refractory forms of periodontitis. In this study, we used a culture plate assay to investigate the effect of suboptimal doses of antimicrobial agents on proteinase activity of Porphyromonas gingivalis. METHODS: A culture plate assay using gelatin as the substrate, which allows a semiquantitative determination of proteinase activity, was developed. Suboptimal inhibitory concentrations of tetracycline, minocycline, doxycycline, metronidazole, penicillin G, or chlorhexidine were added to the medium, and proteolysis zones were determined following the growth of three strains of P. gingivalis. The effect of antimicrobials on outer membrane vesicle-associated gingipains also was determined. RESULTS: The gelatin plate assay was a convenient, simple procedure for investigating the effect of suboptimal inhibitory concentrations of antimicrobial agents on proteinases produced by P. gingivalis. The largest reduction (> 75%) in the proteolysis zones produced by three strains of P. gingivalis was obtained with minocycline. Tetracycline and doxycycline also reduced the proteolysis zones. A suboptimal inhibitory concentration of chlorhexidine increased the proteolysis zones by up to 70%. Metronidazole and penicillin G produced no noticeable effect. The suboptimal inhibitory concentrations of minocycline, tetracycline, and doxycyline did not reduce the activity of outer membrane vesicle-associated Arg- and Lys-gingipains. CONCLUSION: Results from this study suggest that sublethal concentrations of some antimicrobial agents in subgingival sites have the potential to affect the physiology of P. gingivalis, notably by increasing or decreasing the proteolytic activity of the bacteria. 相似文献
949.
Cox CE Carson SS Ely EW Govert JA Garrett JM Brower RG Morris DG Abraham E Donnabella V Spevetz A Hall JB 《American journal of respiratory and critical care medicine》2003,167(1):32-38
Specific methods of mechanical ventilation management reduce mortality and lower health care costs. However, in the face of a predicted deficit of intensivists, it is unclear whether residency programs are training internists to provide effective care for patients who require mechanical ventilation. To evaluate these educational outcomes, we administered a validated 19-item case-based test and survey to resident physicians at 31 diverse U.S. internal medicine residency programs nationwide. Of 347 senior residents, 259 (75%) responded. The mean test score was 74% correct (SD, 14%; range, 37 to 100%). Important items representing evidence-based standards of critical care answered incorrectly were as follows: use of appropriate tidal volume in the acute respiratory distress syndrome (48% incorrect), identifying a patient ready for a weaning trial (38% incorrect), and recognizing indication for noninvasive ventilation (27% incorrect). Most accurately identified pneumothorax (86% correct) and increased intrathoracic positive end-expiratory pressure (93% correct). Better scores were associated with "closed" versus "open" intensive care unit organization (76 versus 71% correct, p = 0.001), resident perception of greater versus lesser ventilator knowledge (79 versus 71% correct, p = 0.001), and graduation from a U.S. versus international medical school (75 versus 69% correct, p = 0.033). Although overall training satisfaction correlated strongly with program use of learning objectives (r = 0.89, p < 0.0001), only 46% reported being satisfied with their mechanical ventilation training. We conclude that senior residents may not be gaining essential evidence-based knowledge needed to provide effective care for patients who require mechanical ventilation. Residency programs should emphasize evidence-based learning objectives to guide mechanical ventilation instruction. 相似文献
950.
Differential responses of HSPs to heat stress in slow and fast regions of rat gastrocnemius muscle 总被引:1,自引:0,他引:1
In a recent study, we showed that the rat slow soleus and fast plantaris muscles exhibited different time courses for the response of specific heat shock proteins (HSPs) after 1 h of heat stress. We hypothesized that these differential responses were related, in part, to the varying fiber type composition of these muscles. To further test this hypothesis, we now have determined the responses of Hsp60, Hsp72, and Hsc73 during the 60 h following exposure to a single bout of heat stress in the deep (relatively high percentage of slow fibers) and superficial regions (only fast fibers) of the adult rat gastrocnemius muscle. The temperature of the musculature in the left hindlimb was elevated to approximately 42 degrees C for 1 h, while the right hindlimb served as a control. Two hours after the heat stress, the Hsp60 levels were increased by 1.3- and 2.0-fold in the deep and superficial regions, respectively. The Hsp72 levels were increased (1.8-fold) in the deep region at 8 h after heat stress, whereas in the superficial region these levels were increased between 4 and 48 h (peak at 36 h by 10-fold) after the heat stress. No changes were observed for Hsc73 in either region of the muscle. Combined with our previous data, the results indicate that the responses of HSPs in the rat hindlimb muscles after a single exposure to heat stress are related to fiber type composition of the muscle or muscle region or to the inherent properties of each HSP. From a clinical viewpoint, these data indicate that specific regions (most likely based on fiber type composition) within a muscle may be affected differentially by any intervention inducing HSPs. 相似文献