全文获取类型
收费全文 | 5582篇 |
免费 | 378篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 68篇 |
儿科学 | 113篇 |
妇产科学 | 45篇 |
基础医学 | 719篇 |
口腔科学 | 110篇 |
临床医学 | 594篇 |
内科学 | 1288篇 |
皮肤病学 | 135篇 |
神经病学 | 432篇 |
特种医学 | 363篇 |
外科学 | 829篇 |
综合类 | 27篇 |
一般理论 | 5篇 |
预防医学 | 348篇 |
眼科学 | 210篇 |
药学 | 351篇 |
中国医学 | 5篇 |
肿瘤学 | 339篇 |
出版年
2023年 | 41篇 |
2022年 | 85篇 |
2021年 | 144篇 |
2020年 | 84篇 |
2019年 | 138篇 |
2018年 | 174篇 |
2017年 | 131篇 |
2016年 | 159篇 |
2015年 | 195篇 |
2014年 | 222篇 |
2013年 | 316篇 |
2012年 | 423篇 |
2011年 | 451篇 |
2010年 | 260篇 |
2009年 | 227篇 |
2008年 | 329篇 |
2007年 | 340篇 |
2006年 | 354篇 |
2005年 | 309篇 |
2004年 | 264篇 |
2003年 | 289篇 |
2002年 | 237篇 |
2001年 | 78篇 |
2000年 | 73篇 |
1999年 | 57篇 |
1998年 | 48篇 |
1997年 | 38篇 |
1996年 | 26篇 |
1995年 | 23篇 |
1994年 | 22篇 |
1993年 | 15篇 |
1992年 | 36篇 |
1991年 | 42篇 |
1990年 | 30篇 |
1989年 | 24篇 |
1988年 | 32篇 |
1987年 | 23篇 |
1986年 | 15篇 |
1985年 | 18篇 |
1984年 | 20篇 |
1983年 | 19篇 |
1981年 | 10篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1975年 | 8篇 |
1974年 | 16篇 |
1973年 | 10篇 |
1972年 | 13篇 |
1970年 | 9篇 |
排序方式: 共有5981条查询结果,搜索用时 15 毫秒
91.
Frilling B Schiele R Gitt AK Zahn R Schneider S Glunz HG Gieseler U Jagodzinski E Senges J;Maximal Individual Therapy in Acute Myocardial Infarction Study Group 《American heart journal》2004,148(2):306-311
Background
A meta-analysis of randomized trials has shown a significant reduction of mortality rate in patients receiving aspirin for secondary prevention after acute myocardial infarction (AMI). However, a significant number of patients do not receive aspirin after AMI. Little is known about why aspirin is withheld or the long-term outcome of these patients today.Methods
The Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) registry is a multicenter registry of patients with AMI in Germany.Results
Of 4902 patients, 509 (10%) did not receive aspirin at the time of discharge from the hospital. The mean follow-up period for these patients was 17 months. Relative contraindications to aspirin were significantly associated with the withholding of aspirin (in-hospital bleeding: odds ratio [OR], 3.56; 95% CI, 1.86-6.80; history of peptic ulcer: OR, 2.49; 95% CI, 1.62-3.83). Absolute contraindications to aspirin were rare (2.2%). Other medications of proven benefit were also given less often in these patients (β-blockers: 49.0% vs 61.9%, P <.001; angiotensin-converting enzyme inhibitors: 65.6% vs 70.2%, P = .06; statins: 12.2% vs 15.1%, P = .10). Patients who were not given aspirin were at high risk for vascular events. They were more likely to have a history of prior AMI (OR, 1.34; 95% CI, 1.02-1.79), were in critical clinical condition at admission more often (cardiogenic shock: OR, 1.98; 95% CI, 1.09-3.56; overt heart failure: OR, 1.6; 95% CI, 1.05-2.3), and received acute revascularization less often (OR, 1.32; 95% CI, 1.05-1.67). The 1-year mortality was 2-times higher in patients who did not receive aspirin than in patients who did receive aspirin (16.5% vs 8.3%, P <.001). A significant association of withheld aspirin at discharge with a higher long-term mortality rate was confirmed with multivariate analysis (OR, 1.62; 95% CI, 1.15-2.29).Conclusions
Ten percent of patients who sustained an AMI did not receive aspirin at the time of hospital discharge. Most of these patients were at high risk for cardiovascular events. Withheld aspirin was significantly associated with higher mortality rate during follow up. 相似文献92.
93.
Bart Dingenen Louis Peeraer Kevin Deschamps Steffen Fieuws Luc Janssens Filip Staes 《Journal of Athletic Training》2015,50(7):688-696
Context
Participants with chronic ankle instability (CAI) use an altered neuromuscular strategy to shift weight from double-legged to single-legged stance. Shoes and foot orthoses may influence these muscle-activation patterns.Objective
To evaluate the influence of shoes and foot orthoses on onset times of lower extremity muscle activity in participants with CAI during the transition from double-legged to single-legged stance.Design
Cross-sectional study.Setting
Musculoskeletal laboratory.Patients or Other Participants
A total of 15 people (9 men, 6 women; age = 21.8 ± 3.0 years, height = 177.7 ± 9.6 cm, mass = 72.0 ± 14.6 kg) who had CAI and wore foot orthoses were recruited.Intervention(s)
A transition task from double-legged to single-legged stance was performed with eyes open and with eyes closed. Both limbs were tested in 4 experimental conditions: (1) barefoot (BF), (2) shoes only, (3) shoes with standard foot orthoses, and (4) shoes with custom foot orthoses (SCFO).Main Outcome Measure(s)
The onset of activity of 9 lower extremity muscles was recorded using surface electromyography and a single force plate.Results
Based on a full-factorial (condition, region, limb, vision) linear model for repeated measures, we found a condition effect (F3,91.8 = 9.39, P < .001). Differences among experimental conditions did not depend on limb or vision condition. Based on a 2-way (condition, muscle) linear model within each region (ankle, knee, hip), earlier muscle-activation onset times were observed in the SCFO than in the BF condition for the peroneus longus (P < .001), tibialis anterior (P = .003), vastus medialis obliquus (P = .04), and vastus lateralis (P = .005). Furthermore, the peroneus longus was activated earlier in the shoes-only (P = .02) and shoes-with-standard-foot-orthoses (P = .03) conditions than in the BF condition. No differences were observed for the hip muscles.Conclusions
Earlier onset of muscle activity was most apparent in the SCFO condition for ankle and knee muscles but not for hip muscles during the transition from double-legged to single-legged stance. These findings might help clinicians understand how shoes and foot orthoses can influence neuromuscular control in participants with CAI.Key Words: footwear, insoles, ankle sprains, neuromuscular system, electromyographyKey Points
- Shoes and foot orthoses accelerated muscle-activation onset times of the ankle and knee but not the hip in participants with chronic ankle instability.
- Earlier muscle-activation onset times were most prominent in the shoes-with-custom-foot-orthoses condition.
- At the ankle, the muscle-activation onset time of the peroneus longus was earlier in the shoes-only, shoes-with-standard-foot-orthoses, and shoes-with-custom-foot-orthoses conditions than in the barefoot condition, and the muscle-activation onset time of the tibialis anterior was earlier in the shoes-with-custom-foot-orthoses condition than in the barefoot condition.
- At the knee, the muscle-activation onset times of the vastus medialis obliquus and vastus lateralis were earlier in the shoes-with-custom-foot-orthoses condition than in the barefoot condition.
- The results may help clinicians understand how shoes and foot orthoses can influence neuromuscular control of the lower extremity in participants with chronic ankle instability.
94.
Avan Suinesiaputra Mihir M. Sanghvi Nay Aung Jose Miguel Paiva Filip Zemrak Kenneth Fung Elena Lukaschuk Aaron M. Lee Valentina Carapella Young Jin Kim Jane Francis Stefan K. Piechnik Stefan Neubauer Andreas Greiser Marie-Pierre Jolly Carmel Hayes Alistair A. Young Steffen E. Petersen 《The international journal of cardiovascular imaging》2018,34(2):281-291
UK Biobank, a large cohort study, plans to acquire 100,000 cardiac MRI studies by 2020. Although fully-automated left ventricular (LV) analysis was performed in the original acquisition, this was not designed for unsupervised incorporation into epidemiological studies. We sought to evaluate automated LV mass and volume (Siemens syngo InlineVF versions D13A and E11C), against manual analysis in a substantial sub-cohort of UK Biobank participants. Eight readers from two centers, trained to give consistent results, manually analyzed 4874 UK Biobank cases for LV end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF) and LV mass (LVM). Agreement between manual and InlineVF automated analyses were evaluated using Bland–Altman analysis and the intra-class correlation coefficient (ICC). Tenfold cross-validation was used to establish a linear regression calibration between manual and InlineVF results. InlineVF D13A returned results in 4423 cases, whereas InlineVF E11C returned results in 4775 cases and also reported LVM. Rapid visual assessment of the E11C results found 178 cases (3.7%) with grossly misplaced contours or landmarks. In the remaining 4597 cases, LV function showed good agreement: ESV ?6.4?±?9.0 ml, 0.853 (mean?±?SD of the differences, ICC) EDV ?3.0?±?11.6 ml, 0.937; SV 3.4?±?9.8 ml, 0.855; and EF 3.5?±?5.1%, 0.586. Although LV mass was consistently overestimated (29.9?±?17.0 g, 0.534) due to larger epicardial contours on all slices, linear regression could be used to correct the bias and improve accuracy. Automated InlineVF results can be used for case-control studies in UK Biobank, provided visual quality control and linear bias correction are performed. Improvements between InlineVF D13A and InlineVF E11C show the field is rapidly advancing, with further improvements expected in the near future. 相似文献
95.
Lise Aunsholt MD PhD Thomas Thymann DVM PhD Niels Qvist MD DMSc David Sigalet MD PhD Steffen Husby MD DMSc Per Torp Sangild DMSc DVSc PhD 《JPEN. Journal of parenteral and enteral nutrition》2015,39(6):668-676
Background: Necrotizing enterocolitis and congenital gastrointestinal malformations in infants often require intestinal resection, with a subsequent risk of short bowel syndrome (SBS). We hypothesized that immediate intestinal adaptation following resection of the distal intestine with placement of a jejunostomy differs between preterm and term neonates. Methods: Preterm or term piglets were born by cesarean section and fed enterally for 2 days. On day 2, piglets were subjected to 50% distal intestinal resection with placement of a jejunostomy. On the following 4–5 days, piglets received parenteral nutrition with gradually increasing doses of enteral nutrition (bovine colostrum). Intestinal tissue samples were collected at delivery and 2 and 6–7 days after birth for histological examination and assessment of digestive enzyme activities. Results: Preterm and term piglets showed similar increases in intestinal weight and digestive enzyme activities from birth to 2 days. On days 6–7 after birth, the remnant intestine showed a similar density (g/cm) and mucosal mass in term and preterm piglets, but villus height, crypt depth, enzyme activities (sucrase, maltase, dipeptidyl peptidase IV [DPPIV]), and hexose uptake capacity were significantly higher in term piglets (P < .05). Preterm piglets were more prone to develop hypoglycemia, respiratory distress syndrome, dehydration, and circulatory instability after surgery compared with term piglets. Conclusion: Studies on intestinal adaptation after resection are feasible in both preterm and term piglets, but intensive clinical support is required when rearing preterm piglets with SBS. Physiological instability and immaturity of the intestine may explain the fact that immediate adaptation after resection is reduced in preterm vs term neonates. 相似文献
96.
Steffen Schmidtendorf Susanne Wiedau Julia Asbrand Brunna Tuschen-Caffier Nina Heinrichs 《Cognitive therapy and research》2018,42(3):273-288
Previous research stated a robust attentional bias to threat in adult anxiety. However, the number of studies analyzing attentional biases in clinically anxious children is limited and results are inconsistent. The present study aims to assess attentional biases in children with social anxiety disorder (n?=?37) and healthy control children (n?=?42) using a free-viewing eye-tracking paradigm. Children viewed different picture pairs consisting of social and non-social stimuli under two conditions (with/without a stressor to activate social threat perception). We found the direction of gaze regarding threatening stimuli to be context-dependent. Both groups showed a hypervigilance-avoidance pattern to angry faces when they were paired with houses. In face–face trials, angry faces were less often initially fixated than neutral or happy faces in both groups. However, schema activation differentially affected initial fixations in angry-neutral face pairs across groups. Children with social anxiety disorder more often initially directed their gaze to angry faces than did healthy control children, indicating a lack of inhibiting threat representations rather than a hypervigilance to threat. 相似文献
97.
Steffen Moritz Jakob Fink Franziska Miegel Katharina Nitsche Vivien Kraft Peter Tonn Lena Jelinek 《Cognitive therapy and research》2018,42(5):650-660
The present study aimed to elucidate the profile of coping in patients with obsessive–compulsive disorder (OCD) in order to discern whether the disorder is characterized by an excess of maladaptive coping skills and/or a lack of adaptive coping skills. Sixty individuals with OCD were compared with 110 individuals with depression and 1050 nonclinical controls on the Maladaptive and Adaptive Coping Styles Questionnaire (MAX). Psychopathology was assessed with the Obsessive–Compulsive Inventory-Revised (OCI-R), the Yale-Brown Obsessive–Compulsive Scale (Y-BOCS), and the Patient Health Questionnaire-9 for depression (PHQ-9). Individuals with OCD and depression displayed more maladaptive coping and avoidance as well as less adaptive coping than nonclinical controls. Importantly, adaptive coping was significantly lower in individuals with OCD than in those with depression at a medium effect size, whereas the clinical groups were indistinguishable on maladaptive coping and avoidance. Lack of adaptive coping was strongly correlated with resistance to symptoms and poor insight in OCD (Y-BOCS), even after controlling for depression. Lack of adaptive coping skills may represent a specific pathogenetic factor in OCD. Longitudinal studies need to clarify whether strengthening adaptive skills during childhood and adolescence may help to prevent the progression from subclinical to manifest OCD. 相似文献
98.
99.
100.