全文获取类型
收费全文 | 23706篇 |
免费 | 1818篇 |
国内免费 | 85篇 |
专业分类
耳鼻咽喉 | 395篇 |
儿科学 | 814篇 |
妇产科学 | 377篇 |
基础医学 | 2431篇 |
口腔科学 | 529篇 |
临床医学 | 2170篇 |
内科学 | 5237篇 |
皮肤病学 | 550篇 |
神经病学 | 1276篇 |
特种医学 | 1110篇 |
外国民族医学 | 1篇 |
外科学 | 4545篇 |
综合类 | 329篇 |
一般理论 | 15篇 |
预防医学 | 1162篇 |
眼科学 | 824篇 |
药学 | 2041篇 |
中国医学 | 38篇 |
肿瘤学 | 1765篇 |
出版年
2024年 | 61篇 |
2023年 | 223篇 |
2022年 | 400篇 |
2021年 | 985篇 |
2020年 | 477篇 |
2019年 | 814篇 |
2018年 | 944篇 |
2017年 | 611篇 |
2016年 | 647篇 |
2015年 | 671篇 |
2014年 | 1011篇 |
2013年 | 1187篇 |
2012年 | 1739篇 |
2011年 | 1709篇 |
2010年 | 869篇 |
2009年 | 817篇 |
2008年 | 1277篇 |
2007年 | 1212篇 |
2006年 | 1123篇 |
2005年 | 981篇 |
2004年 | 883篇 |
2003年 | 749篇 |
2002年 | 645篇 |
2001年 | 587篇 |
2000年 | 550篇 |
1999年 | 489篇 |
1998年 | 166篇 |
1997年 | 138篇 |
1996年 | 140篇 |
1995年 | 145篇 |
1994年 | 114篇 |
1993年 | 100篇 |
1992年 | 268篇 |
1991年 | 284篇 |
1990年 | 248篇 |
1989年 | 214篇 |
1988年 | 212篇 |
1987年 | 219篇 |
1986年 | 194篇 |
1985年 | 177篇 |
1984年 | 111篇 |
1983年 | 127篇 |
1982年 | 85篇 |
1981年 | 70篇 |
1980年 | 59篇 |
1979年 | 129篇 |
1978年 | 77篇 |
1977年 | 69篇 |
1974年 | 65篇 |
1973年 | 88篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
31.
J R Patel 《Oral surgery, oral medicine, and oral pathology》1979,48(5):479-483
The purpose of this investigation was to investigate intraoral radiography in regards to the frequency of errors, the types of error necessitating retakes, and the relationship of error frequency to the teeth area examined and type x-ray cone used. The present study used 283 complete mouth radiographic surveys made, and 890 radiographs were found to be clinically unacceptable for one or more errors in technique. Thirteen and one-tenth errors per one hundred radiographs were found in this study. The three major radiographic errors occurring in this study were incorrect film placement (49.9 percent), cone-cutting (20.8 percent), and incorrect vertical angulation (12.5 percent). 相似文献
32.
Microbial complexes in supragingival plaque 总被引:1,自引:0,他引:1
Background/aims: To examine microbial communities in supragingival biofilm samples.
Methods: Supragingival plaque samples were taken from 187 subjects at baseline ( n = 4745). Fifty-five subjects provided supragingival plaque samples at 1–7 days after professional tooth cleaning ( n = 1456); 93 subjects provided 8044 samples between 3 and 24 months post-therapy. All samples were individually analyzed for their content of 40 bacterial species using checkerboard DNA–DNA hybridization. Microbial associations among species were sought using cluster analysis and community ordination techniques for the three groups separately.
Results: Six complexes were formed for the baseline samples. Similar complexes were formed for the samples taken 3–24 months post-therapy. However, distinct changes were observed in microbial communities in samples taken during the 7 days of plaque redevelopment. The complexes related to clinical parameters of periodontal disease.
Conclusion: There were specific microbial complexes in supragingival plaque that were similar to those found in subgingival plaque samples with a few minor differences. The relation of previously unclustered taxa to the complexes was also described. 相似文献
Methods: Supragingival plaque samples were taken from 187 subjects at baseline ( n = 4745). Fifty-five subjects provided supragingival plaque samples at 1–7 days after professional tooth cleaning ( n = 1456); 93 subjects provided 8044 samples between 3 and 24 months post-therapy. All samples were individually analyzed for their content of 40 bacterial species using checkerboard DNA–DNA hybridization. Microbial associations among species were sought using cluster analysis and community ordination techniques for the three groups separately.
Results: Six complexes were formed for the baseline samples. Similar complexes were formed for the samples taken 3–24 months post-therapy. However, distinct changes were observed in microbial communities in samples taken during the 7 days of plaque redevelopment. The complexes related to clinical parameters of periodontal disease.
Conclusion: There were specific microbial complexes in supragingival plaque that were similar to those found in subgingival plaque samples with a few minor differences. The relation of previously unclustered taxa to the complexes was also described. 相似文献
33.
Swathi Kaliki Arpita Maniar Anamika Patel Vijay Anand Reddy Palkonda Ashik Mohamed 《International ophthalmology》2020,40(1):99-107
To compare the clinical presentation and outcomes of retinoblastoma (RB) based on age at presentation. Retrospective comparative study of 1940 eyes of 1450 children with RB. Presentation of RB with enlarged eyeball and eyelid swelling (2% and < 1% in ≤ 1 year, 4% and 2% in > 1–2 years, 7% and 2% in > 2–3 years, and 12% and 4% in > 3 years; p < 0.0001 and p = 0.05, respectively) is more common with increasing age. Based on the 8th edition of American Joint Committee Classification, T1 is more common in children younger than 1 year (27%), while T4 is more common in children > 3 years of age (20%) (p < 0.0001). Kaplan–Meier (KM) estimate at 1 and 5 years for globe salvage was 64% and 58% in children ≤ 1 year of age versus 30% and 20% in children > 3 years, respectively [Hazard ratio (HR) = 2.48; p < 0.0001], and KM estimate at 1 and 5 years for life salvage was 99% and 97% in children ≤ 1 year of age versus 89% and 78% in children older than 3 years, respectively (HR = 7.65; p < 0.0001). Uncommon clinical features of RB including enlarged eyeball and eyelid swelling are more common with increasing age. Younger age at presentation with RB is associated with better prognosis including higher chances of life and globe salvage. 相似文献
34.
35.
36.
The practitioner of emergency medicine is routinely faced with patients in need of emergent procedures and pain control and sedation. Our challenge is to make our patients' experiences as painless and as safe as possible, while maximizing our ability to perform the procedure at hand; this is not always an easy task given the propensity of each human body to react differently to interventions and stimuli. We can best meet this challenge by understanding how our patients and pharmaceutical agents intermingle in the risk-benefit equation we formulate before starting our "experiment." Coupling this information with fundamentally sound patient care and monitoring will minimize bad experiences with PSA for both the patient and practitioner. 相似文献
37.
Jace C. Nielsen Dwain Tolbert Mahlaqa Patel Kenneth G. Kowalski David L. Wesche 《Epilepsia》2014,55(12):e134-e138
We predicted vigabatrin dosages for adjunctive therapy for pediatric patients with refractory complex partial seizures (rCPS) that would produce efficacy comparable to that observed for approved adult dosages. A dose–response model related seizure‐count data to vigabatrin dosage to identify dosages for pediatric rCPS patients. Seizure‐count data were obtained from three pediatric and two adult rCPS clinical trials. Dosages were predicted for oral solution and tablet formulations. Predicted oral solution dosages to achieve efficacy comparable to that of a 1 g/day adult dosage were 350 and 450 mg/day for patients with body weight ranges 10–15 and >15–20 kg, respectively. Predicted oral solution dosages for efficacy comparable to a 3 g/day adult dosage were 1,050 and 1,300 mg/day for weight ranges 10–15 and >15–20 kg, respectively. Predicted tablet dosage for efficacy comparable to a 1 g/day adult dosage was 500 mg/day for weight ranges 25–60 kg. Predicted tablet dosage for efficacy comparable to a 3 g/day adult dosage was 2,000 mg for weight ranges 25–60 kg. Vigabatrin dosages were identified for pediatric rCPS patients with body weights ≥10 kg. 相似文献
38.
Parul B. Patel MD MPH Maria Carmen G. Diaz MD Jonathan E. Bennett MD Magdy W. Attia MD 《Academic emergency medicine》2007,14(1):1-5
Objectives
Conjunctivitis is a common cause of primary care and emergency department (ED) visits. There is a paucity of data in recent literature on the prevalence of pediatric bacterial conjunctivitis, and there are no evidence-based clinical guidelines for empirical treatment. The study objective was to describe clinical features most predictive of bacterial conjunctivitis.
Methods
This was a prospective study in a children's hospital ED. Conjunctival swabs for bacterial culture were obtained from patients aged 1 month to 18 years presenting with red or pink eye and/or the diagnosis of conjunctivitis.
Results
A total of 111 patients were enrolled over one year. Patients had a mean (±SD) age of 33.2 (±37.5) months, and 55% were male. Eighty-seven patients (78%) had positive bacterial cultures. Nontypeable Haemophilus influenzae accounted for 82% (71/87), Streptococcus pneumoniae for 16% (14/87), and Staphylococcus aureus for 2.2% (2/87). Five clinical variables were significantly associated with a positive bacterial culture. Regression analysis revealed that the combination of a history of gluey or sticky eyelids and the physical finding of mucoid or purulent discharge had a posttest probability of 96% (95% confidence interval = 90% to 99%). Subjective scoring by physicians for a positive culture was 50.6%.
Conclusions
Conjunctivitis in children is predominantly bacterial, with nontypeable H. influenzae being the most common organism. A history of gluey or sticky eyelids and physical findings of mucoid or purulent discharge are highly predictive of bacterial infection. Based on the above data, empirical ophthalmic antibiotic therapy may be appropriate in children presenting with conjunctivitis. 相似文献
Conjunctivitis is a common cause of primary care and emergency department (ED) visits. There is a paucity of data in recent literature on the prevalence of pediatric bacterial conjunctivitis, and there are no evidence-based clinical guidelines for empirical treatment. The study objective was to describe clinical features most predictive of bacterial conjunctivitis.
Methods
This was a prospective study in a children's hospital ED. Conjunctival swabs for bacterial culture were obtained from patients aged 1 month to 18 years presenting with red or pink eye and/or the diagnosis of conjunctivitis.
Results
A total of 111 patients were enrolled over one year. Patients had a mean (±SD) age of 33.2 (±37.5) months, and 55% were male. Eighty-seven patients (78%) had positive bacterial cultures. Nontypeable Haemophilus influenzae accounted for 82% (71/87), Streptococcus pneumoniae for 16% (14/87), and Staphylococcus aureus for 2.2% (2/87). Five clinical variables were significantly associated with a positive bacterial culture. Regression analysis revealed that the combination of a history of gluey or sticky eyelids and the physical finding of mucoid or purulent discharge had a posttest probability of 96% (95% confidence interval = 90% to 99%). Subjective scoring by physicians for a positive culture was 50.6%.
Conclusions
Conjunctivitis in children is predominantly bacterial, with nontypeable H. influenzae being the most common organism. A history of gluey or sticky eyelids and physical findings of mucoid or purulent discharge are highly predictive of bacterial infection. Based on the above data, empirical ophthalmic antibiotic therapy may be appropriate in children presenting with conjunctivitis. 相似文献
39.
40.