全文获取类型
收费全文 | 1745篇 |
免费 | 142篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 81篇 |
妇产科学 | 20篇 |
基础医学 | 214篇 |
口腔科学 | 31篇 |
临床医学 | 169篇 |
内科学 | 227篇 |
皮肤病学 | 26篇 |
神经病学 | 80篇 |
特种医学 | 167篇 |
外科学 | 359篇 |
综合类 | 105篇 |
预防医学 | 161篇 |
眼科学 | 19篇 |
药学 | 137篇 |
肿瘤学 | 117篇 |
出版年
2021年 | 17篇 |
2020年 | 11篇 |
2019年 | 25篇 |
2018年 | 27篇 |
2017年 | 21篇 |
2016年 | 23篇 |
2015年 | 33篇 |
2014年 | 49篇 |
2013年 | 50篇 |
2012年 | 74篇 |
2011年 | 55篇 |
2010年 | 52篇 |
2009年 | 44篇 |
2008年 | 71篇 |
2007年 | 96篇 |
2006年 | 71篇 |
2005年 | 55篇 |
2004年 | 60篇 |
2003年 | 65篇 |
2002年 | 57篇 |
2001年 | 57篇 |
2000年 | 53篇 |
1999年 | 56篇 |
1998年 | 47篇 |
1997年 | 35篇 |
1996年 | 28篇 |
1995年 | 29篇 |
1994年 | 35篇 |
1993年 | 29篇 |
1992年 | 32篇 |
1991年 | 46篇 |
1990年 | 35篇 |
1989年 | 46篇 |
1988年 | 45篇 |
1987年 | 34篇 |
1986年 | 47篇 |
1985年 | 29篇 |
1984年 | 41篇 |
1983年 | 38篇 |
1982年 | 25篇 |
1981年 | 16篇 |
1980年 | 17篇 |
1979年 | 16篇 |
1978年 | 12篇 |
1977年 | 7篇 |
1976年 | 9篇 |
1975年 | 14篇 |
1972年 | 7篇 |
1970年 | 8篇 |
1937年 | 7篇 |
排序方式: 共有1919条查询结果,搜索用时 15 毫秒
1.
2.
目的由于卒中风险随着狭窄严重程度的增加而升高,因此认为颈内动脉(ICA)接近闭塞患者的卒中风险很高。在现有的随机试验中,还没有专门针对这种情况进行探讨,因此其处理尚存在争汶。方法:对相关文献进行系统评价。结果:对ICA接近闭塞患者的处理还存在争议:一些学者支持进行干预,而另一些学者则认为存在风险或没有益处而反对进行干预。在ICA接近闭塞的有症状患者中进行一项比较外科治疗与最佳内科治疗的多中心前瞻性随机试验似乎非常困难,因为这类研究需要大量的患者。尽管如此,基于目前的证据,似乎很难拒绝手术治疗。结论:由于目前对ICA接近闭塞患者的最佳处理方案仍存在着争议,因此需要前瞻性观察性研究以证实其在有症状和无症状人群中的患病率以及相关的卒中风险。基于目前的证据,大多数医疗中心选择手术治疗,但它相对干内科治疗的特粱尚右待证章. 相似文献
3.
Valves in the subclavian and internal jugular veins were studied in 100 autopsy cases (52 men and 48 women; range, 18 to 91 years old; mean, 67 years). In 87 cases, valves were present in all 4 veins, and in 13 cases, valves anatomically were absent from 16 veins, 9 of which were the left internal jugular vein. The average distance from the valve to the junction with the innominate vein was 1.7 cm for the subclavian vein and 0.3 cm for the internal jugular vein. Cuspid height averaged 0.9 cm. Valves were bicuspid in 347 (90%) and unicuspid in 39 (10%); unicuspid valves were more common in the internal jugular vein than in the subclavian vein. Catheter-induced trauma was observed in 4 cases and implied in 4 more. These findings may have important implications concerning the failure, in some cases, of closed-chest cardiac resuscitation to maintain forward blood flow at adequate pressure. 相似文献
4.
5.
J.M. Smith D. Stablein A. Singh W. Harmon R.A. McDonald 《American journal of transplantation》2006,6(3):585-588
Graft thrombosis is the most common cause of first year graft failure in pediatric renal transplantation. The North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) database was analyzed for cases of graft failure due to thrombosis among patients transplanted from 1998 to 2004. The impact of interleukin-2 (IL-2) receptor antagonists as induction therapy was determined. There were a total of 51 graft failures due to thrombosis among the 2750 reported renal transplants (1.85%) (95% CI (1.39%, 2.41%)). This represents the most common cause of graft loss during the first year post-transplant accounting for 35% of first year losses and 18% of all graft losses. The incidence of thrombosis among patients who received IL-2 receptor antibodies was 1.07% (12/1126) compared to 2.40% (39/1624) among patients who did not (OR 0.44, 95% CI 0.23, 0.84, p = 0.014). Use of IL-2 receptor blockade was the only significant prognostic factor in a multivariate model with previously identified risk factors. Analysis of NAPRTCS data found that the use of IL-2 receptor antibodies as induction therapy is associated with a significantly decreased risk of graft failure due to thrombosis. This provocative finding requires further investigation to determine whether thrombotic failure can be decreased by this therapeutic strategy. 相似文献
6.
7.
American Indian--Alaska Native youth health. 总被引:6,自引:0,他引:6
OBJECTIVE--To assess risk behaviors, health problems, worries and concerns, and resiliency-promoting factors among American Indian-Alaska Native adolescents. DESIGN--Survey. SETTING--Nonurban schools from eight Indian Health Service areas. PARTICIPANTS--A total of 13,454 seventh- through 12th-grade American Indian-Alaska Native youths. MAIN OUTCOME MEASURES--revised version of the Adolescent Health Survey, a comprehensive, anonymous, self-report questionnaire with 162 items addressing 10 dimensions of health. RESULTS--Poor physical health was reported by 2% of the study sample and was significantly correlated with social risk factors of physical and/or sexual abuse, suicide attempts, substance abuse, poor school performance, and nutritional inadequacies. Injury risk behaviors included never wearing seatbelts (44%), drinking and driving (37.9% of driving 10th through 12th graders), and riding with a driver who had been drinking (21.8%). Physical and sexual abuse prevalence was 10% and 13%, respectively, with 23.9% of females reporting physical abuse and 21.6% of females reporting sexual abuse by the 12th grade. Almost 6% of the entire sample endorsed signs of severe emotional distress. Eleven percent of the teens surveyed knew someone who had killed himself or herself, and 17% had attempted suicide themselves. Sixty-five percent of males and 56.8% of females reported having had intercourse by the 12th grade. Weekly or more frequent alcohol use rose from 8.2% of seventh graders to 14.1% by the 12th grade; for males, the survey noted an increase in regular alcohol use of 3% to 5% a year to 27.3% by the 12th grade. For each variable measured, rates are much higher for American Indian adolescents than those for rural white Minnesota youth, except for age at first intercourse and alcohol use. CONCLUSIONS--American Indian-Alaska Native adolescents reported high rates of health-compromising behaviors and risk factors related to unintentional injury, substance use, poor self-assessed health status, emotional distress, and suicide. Interventions must be culturally sensitive, acknowledge the heterogeneity of Indian populations, be grounded in cultural traditions that promote health, and be developed with full participation of the involved communities. 相似文献
8.
Risk of spinal cord dysfunction in patients undergoing thoracoabdominal aortic replacement. 总被引:1,自引:0,他引:1
L H Hollier S R Money T C Naslund C D Proctor W C Buhrman R J Marino D E Harmon F J Kazmier 《American journal of surgery》1992,164(3):210-3; discussion 213-4
The records of 150 consecutive patients undergoing thoracoabdominal aortic replacement from 1980 to 1991 were retrospectively reviewed. There were 89 men and 61 women; mean age was 67.8 years (range: 33 to 88 years). Since June 1989, a multimodality prospective perioperative protocol was used to reduce the risk of spinal cord dysfunction. Ischemia is minimized by complete intercostal reimplantation whenever possible, cerebrospinal fluid drainage, and maintenance of proximal hypertension during cross-clamping. Spinal cord metabolism is reduced by moderate hypothermia, high-dose barbiturates, and avoidance of hyperglycemia. Reperfusion injury is minimized by the use of mannitol, steroids, and calcium channel blockers. Ninety-seven percent of patients survived long enough for evaluation of their neurologic function. Spinal cord dysfunction was reduced from 6 of 108 (6%) in the preprotocol group to 0 of 42 in the protocol group (0%) (p less than 0.01). The overall 30-day operative mortality was not significantly different between the groups (9% versus 12%, p = NS). A multimodality protocol appears to be effective in reducing the risk of spinal cord injury during thoracoabdominal aortic replacement. 相似文献
9.
B A Chaudhary T K Chaudhary R C Kolbeck J D Harmon W A Speir 《Southern medical journal》1986,79(9):1061-1063
Four patients with mild to moderate obstructive sleep apnea were monitored first in the supine posture to establish a diagnosis of obstructive sleep apnea (apnea indices 33, 12, 22, 36). A second polysomnogram, obtained while the patients slept in the lateral posture, showed a dramatic decrease in apnea (apnea indices 5, 0, 0.2, and 0) and snoring. Each patient had an enlarged uvula, which moved to the side in the lateral posture. We conclude that sleeping in the lateral posture may be therapeutic in some patients with obstructive sleep apneas. 相似文献
10.
Rupture of the distal biceps tendon: evaluation with MR imaging 总被引:2,自引:0,他引:2