全文获取类型
收费全文 | 4563篇 |
免费 | 346篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 102篇 |
儿科学 | 71篇 |
妇产科学 | 97篇 |
基础医学 | 640篇 |
口腔科学 | 80篇 |
临床医学 | 548篇 |
内科学 | 730篇 |
皮肤病学 | 59篇 |
神经病学 | 423篇 |
特种医学 | 162篇 |
外科学 | 716篇 |
综合类 | 38篇 |
一般理论 | 5篇 |
预防医学 | 510篇 |
眼科学 | 128篇 |
药学 | 278篇 |
中国医学 | 21篇 |
肿瘤学 | 308篇 |
出版年
2023年 | 46篇 |
2022年 | 103篇 |
2021年 | 255篇 |
2020年 | 100篇 |
2019年 | 184篇 |
2018年 | 175篇 |
2017年 | 133篇 |
2016年 | 114篇 |
2015年 | 137篇 |
2014年 | 207篇 |
2013年 | 240篇 |
2012年 | 344篇 |
2011年 | 323篇 |
2010年 | 143篇 |
2009年 | 132篇 |
2008年 | 195篇 |
2007年 | 192篇 |
2006年 | 192篇 |
2005年 | 144篇 |
2004年 | 152篇 |
2003年 | 132篇 |
2002年 | 136篇 |
2001年 | 60篇 |
2000年 | 58篇 |
1999年 | 48篇 |
1998年 | 25篇 |
1997年 | 22篇 |
1996年 | 21篇 |
1995年 | 20篇 |
1992年 | 43篇 |
1991年 | 42篇 |
1990年 | 50篇 |
1989年 | 61篇 |
1988年 | 40篇 |
1987年 | 48篇 |
1986年 | 43篇 |
1985年 | 41篇 |
1984年 | 33篇 |
1983年 | 31篇 |
1982年 | 21篇 |
1980年 | 25篇 |
1979年 | 21篇 |
1978年 | 23篇 |
1977年 | 23篇 |
1975年 | 31篇 |
1974年 | 20篇 |
1973年 | 25篇 |
1972年 | 22篇 |
1971年 | 22篇 |
1970年 | 25篇 |
排序方式: 共有4916条查询结果,搜索用时 15 毫秒
131.
132.
133.
Moria J. Smoski Shian-Ling Keng Jie Lisa Ji Tyler Moore Jared Minkel Gabriel S. Dichter 《Social cognitive and affective neuroscience》2015,10(9):1187-1194
Mood disorders are characterized by impaired emotion regulation abilities, reflected in alterations in frontolimbic brain functioning during regulation. However, little is known about differences in brain function when comparing regulatory strategies. Reappraisal and emotional acceptance are effective in downregulating negative affect, and are components of effective depression psychotherapies. Investigating neural mechanisms of reappraisal vs emotional acceptance in remitted major depressive disorder (rMDD) may yield novel mechanistic insights into depression risk and prevention. Thirty-seven individuals (18 rMDD, 19 controls) were assessed during a functional magnetic resonance imaging task requiring reappraisal, emotional acceptance or no explicit regulation while viewing sad images. Lower negative affect was reported following reappraisal than acceptance, and was lower following acceptance than no explicit regulation. In controls, the acceptance > reappraisal contrast revealed greater activation in left insular cortex and right prefrontal gyrus, and less activation in several other prefrontal regions. Compared with controls, the rMDD group had greater paracingulate and right midfrontal gyrus (BA 8) activation during reappraisal relative to acceptance. Compared with reappraisal, acceptance is associated with activation in regions linked to somatic and emotion awareness, although this activation is associated with less reduction in negative affect. Additionally, a history of MDD moderated these effects. 相似文献
134.
Tyler R. Hart Richard R. J. Cousley Leonard S. Fishman Ross H. Tallents 《The Angle orthodontist》2015,85(6):941
Objective:To evaluate skeletal and dental changes after intrusion of the maxillary molars in subjects with anterior open bite.Materials and Methods:This retrospective cephalometric study evaluated skeletal and dental changes resulting from the use of maxillary orthodontic mini-implants in 31 consecutively treated patients. Radiographs were taken at the start and end of maxillary molar intrusion to evaluate the associated changes. Statistical analysis was performed using a one-sample t-test.Results:The mean treatment observation time was 1.31 years (SD = 2.03). The maxillary first molars (P = 0.0026) and second molars (P = 0.039) were intruded. However, the mandibular first molars (P = 0.0004) and second molars (P = 0.003) erupted in adolescent patients. Both the maxillary and mandibular first molars inclined distally (P = 0.025 and P = 0.044, respectively). The mandibular plane angle decreased (P = 0.036), lower facial height decreased (P = 0.002), and the occlusal plane angle increased (P = 0.009). The overbite increased (P < .0001). The ANB angle decreased (P < .0001). Mandibular dental and skeletal changes were more apparent in adolescents, while adults tended toward maxillary changes.Conclusions:Vertical traction from orthodontic mini-implants reduces the maxillary posterior dentoalveolar height, thereby assisting orthodontic closure of anterior open bite. However, simultaneous eruption or extrusion of the mandibular molars should be controlled. Adolescent patients tend to demonstrate more favorable effects of mandibular autorotation than do adults. 相似文献
135.
136.
Mark M. Brodie Jill C. Newman Tyler Smith Don C. Rockey 《The American journal of medicine》2018,131(5):573.e9-573.e15
Background
Direct-acting oral anticoagulants (DOACs), which have gained approval for stroke prevention in nonvalvular atrial fibrillation and treatment of venous thromboembolism, have become increasingly preferred over warfarin given their predictable pharmacodynamics, lack of required monitoring, and superior outcomes. Direct-acting oral anticoagulants have been shown to be associated with an increased frequency of gastrointestinal bleeding compared with warfarin, but the severity and characteristics of gastrointestinal bleeding in these patients is poorly understood.Methods
We retrospectively evaluated electronic medical records of patients with gastrointestinal bleeding (n = 8496) from 2010-2016. We identified 61 patients with gastrointestinal bleeding episodes while treated with DOACs (rivaroxaban, dabigatran, or apixaban) and 123 patients with gastrointestinal bleeding while taking warfarin. We randomly selected a control group of 296 patients with gastrointestinal bleeding who were not receiving anticoagulation treatment from the same sample. Outcomes included the need for hospitalization, blood transfusion, endoscopic or surgical intervention, and 30-day mortality.Results
The DOAC and warfarin groups were similar in terms of age and underlying comorbidity (assessed using the Charlson Comorbidity Index), but the DOAC group had greater concomitant aspirin use. Gastrointestinal bleeding was classified as upper (n = 186), lower (n = 88), anorectal (n = 183), small bowel (n = 9), and indeterminate (n = 14). After adjusting for differences in baseline variables, the DOAC group had fewer hospitalizations and required fewer transfusions than the warfarin group. The DOAC and control groups were not statistically different for all outcomes. There were no significant mortality differences among groups.Conclusion
Although prior studies have shown a higher frequency of gastrointestinal bleeding in patients treated with DOACs compared with warfarin, our data suggest that gastrointestinal bleeding in patients taking DOACs may be less severe. These differences occurred despite significantly greater concomitant aspirin use in the DOAC group compared with warfarin users. 相似文献137.
Panupong Jiamsripong Tadaaki Honda Christina S Reuss R Todd Hurst Hari P Chaliki Diane E Grill Stephen L Schneck Rochelle Tyler Bijoy K Khandheria Steven J Lester 《European journal of echocardiography》2008,9(3):351-355
AIM: To compare and contrast 3 different echocardiographic methods used to measure left atrial (LA) volume: biplane area length (AL), biplane modified Simpson (SIMP), and prolate ellipse (PE) methods. METHODS AND RESULTS: A review of consecutive patients who presented to our outpatient echocardiography laboratory for a resting transthoracic study between April 2006 and May 2006 was performed. Echocardiograms were reexamined and LA volume measured using the AL, SIMP, and PE methods. Of 102 consecutive patients evaluated, 97 had a measure of LA volume using all 3 methods. A significant difference in the measurement of mean +/- SD LA volume was noted among the 3 different methods: 37 +/- 16 mL/m(2) for AL, 34 +/- 14 mL/m(2) for SIMP, and 27 +/- 12 mL/m(2) for PE. The PE method yielded routinely smaller values compared with either the AL or SIMP method (P < 0.001). Differences increased with increased LA volume. The SIMP method derived consistently smaller (<5 mL/m(2)) values than those of the AL method, consistent across the full range of LA volumes. CONCLUSION: Significant differences exist among these 3 commonly used methods for measuring LA volume. Standardization of the measurement of LA volume is recommended. 相似文献
138.
Tyler F. Beck Philippe M. Campeau Shalini N. Jhangiani Tomasz Gambin Alexander H. Li Reem Abo‐Zahrah Valerie K. Jordan Andres Hernandez‐Garcia Wojciech K. Wiszniewski Donna Muzny Richard A. Gibbs Eric Boerwinkle James R. Lupski Brendan Lee Willie Reardon Daryl A. Scott 《American journal of medical genetics. Part A》2015,167(4):831-836
139.
Andrew J. Denisuik James A. Karlowsky Tyler Denisuik Wright W. Nichols Thomas A. Keating Heather J. Adam Melanie Baxter Andrew Walkty George G. Zhanel 《Antimicrobial agents and chemotherapy》2015,59(6):3623-3626
The mechanism of aminoglycoside resistance among 338 gentamicin-nonsusceptible Gram-negative bacteria (207 Enterobacteriaceae and 131 Pseudomonas aeruginosa) was assessed, and the in vitro activity of ceftazidime-avibactam against these isolates was determined. Aminoglycoside-modifying enzymes were detected in 91.8% of Enterobacteriaceae and 13.7% of P. aeruginosa isolates. A single strain of Klebsiella pneumoniae harbored a 16S rRNA methylase (ArmA). The ceftazidime-avibactam MIC90 values were 0.5 μg/ml (MIC, ≤8 μg/ml for 100% of isolates) and 16 μg/ml (MIC, ≤8 μg/ml for 87.8% of isolates) against gentamicin-nonsusceptible Enterobacteriaceae and P. aeruginosa isolates, respectively. 相似文献
140.
John B. Jemmott III G. Anita Heeren Lulama Sidloyi C. Show Marange Joanne C. Tyler Zolani Ngwane 《AIDS and behavior》2014,18(6):1027-1036
When children know their HIV serostatus, they are more likely to cooperate with steps to manage their health and the risk of transmitting HIV to others. Mounting evidence indicates that caregivers often do not disclose to HIV-positive children that the children are living with HIV, but little is known about the modifiable determinants of pediatric HIV disclosure. The present study examined theory-of-planned-behavior predictors of the intention to disclose to children their HIV diagnosis. The participants were 100 caregivers of HIV-positive children in Eastern Cape Province, South Africa. Proportional-odds logistic regression analysis revealed that normative support for disclosure and caregiver-child communication predicted the intention to disclose, whereas behavioral beliefs regarding the consequences of disclosing and self-efficacy to disclose did not. The results suggest that interventions to increase pediatric HIV disclosure in South Africa should help caregivers enlist support for disclosure among important referents and improve communication with their HIV-infected children. 相似文献