全文获取类型
收费全文 | 11060篇 |
免费 | 1251篇 |
国内免费 | 49篇 |
专业分类
耳鼻咽喉 | 64篇 |
儿科学 | 294篇 |
妇产科学 | 371篇 |
基础医学 | 1516篇 |
口腔科学 | 217篇 |
临床医学 | 1279篇 |
内科学 | 2552篇 |
皮肤病学 | 156篇 |
神经病学 | 1301篇 |
特种医学 | 443篇 |
外科学 | 1209篇 |
综合类 | 210篇 |
一般理论 | 11篇 |
预防医学 | 1155篇 |
眼科学 | 160篇 |
药学 | 677篇 |
肿瘤学 | 745篇 |
出版年
2021年 | 121篇 |
2020年 | 115篇 |
2019年 | 145篇 |
2018年 | 173篇 |
2017年 | 155篇 |
2016年 | 168篇 |
2015年 | 204篇 |
2014年 | 276篇 |
2013年 | 376篇 |
2012年 | 523篇 |
2011年 | 509篇 |
2010年 | 306篇 |
2009年 | 286篇 |
2008年 | 548篇 |
2007年 | 532篇 |
2006年 | 474篇 |
2005年 | 487篇 |
2004年 | 403篇 |
2003年 | 354篇 |
2002年 | 312篇 |
2001年 | 312篇 |
2000年 | 372篇 |
1999年 | 312篇 |
1998年 | 141篇 |
1997年 | 131篇 |
1996年 | 139篇 |
1995年 | 116篇 |
1994年 | 92篇 |
1993年 | 100篇 |
1992年 | 253篇 |
1991年 | 272篇 |
1990年 | 245篇 |
1989年 | 240篇 |
1988年 | 200篇 |
1987年 | 220篇 |
1986年 | 242篇 |
1985年 | 223篇 |
1984年 | 164篇 |
1983年 | 150篇 |
1982年 | 106篇 |
1981年 | 89篇 |
1980年 | 94篇 |
1979年 | 171篇 |
1978年 | 103篇 |
1977年 | 90篇 |
1975年 | 96篇 |
1974年 | 101篇 |
1973年 | 102篇 |
1972年 | 93篇 |
1971年 | 92篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
Stuart Harris John P LeMaitre Graham Mackenzie Keith A A Fox Martin A Denvir 《European heart journal》2003,24(9):871-878
AIMS: Recent guidelines recommend regular exercise in the management of patients with chronic heart failure (CHF). This study was designed to compare the safety and efficacy of conventional bicycle exercise and functional electrical stimulation (FES) of the legs as forms of home-based exercise training for patients with stable CHF. METHODS AND RESULTS: Forty-six patients (38 male) with stable NYHA Class II/III heart failure underwent a 6-week training programme using either a bicycle ergometer or electrical stimulation of the quadriceps and gastrocnemius muscles. In the bike group, significant increases were seen in 6-min walk (44.6m, 95% confidence interval (CI) 29.3-60.9 m), treadmill exercise time (110 s, 95% CI 72.2-148.0 s), maximum leg strength (5.32 kg, 95% CI 3.18-7.45 kg), and quadriceps fatigue index (0.08, 95% CI 0.04-0.12) following training. In the stimulator group, similar significant increases were seen following training for 6-min walk (40.6m, 95% CI 28.2-53.0m), treadmill exercise time (67 s, 95% CI 11.8-121.8s), maximum leg strength (5.35 kg, 95% CI 1.53-9.17 kg), and quadriceps fatigue index (0.10, 95% CI 0.04-0.17). Peak VO(2)did not change in either group following training, indicating a low-intensity regime. Quality of life scores improved following training when the bicycle and stimulator groups were considered together, but not when considered separately (-0.43, 95% CI -8.13 to -0.56). CONCLUSIONS: FES produces beneficial changes in muscle performance and exercise capacity in patients with CHF. Within this study, the benefits were similar to those observed following bicycle training. FES could be offered to patients with heart failure as an alternative to bicycle training as part of a home-based rehabilitation programme. 相似文献
993.
Albuterol is a specific beta-2 agonist that has been reported to be effective in treating infants and children with bronchospastic pulmonary disease. The use of oral albuterol has not been investigated in patients with bronchopulmonary dysplasia (BPD). Thirty premature infants were randomized to receive oral albuterol (0.15 mg/kg/dose q8h) or a volume- and color-matched placebo (D5/W). Pulmonary functions were evaluated at baseline and at 48 and 96 hours after entry to the study. The study was also designed for crossover from placebo to albuterol or albuterol to caffeine in the event that the infant's total pulmonary resistance did not improve at the time of the 48 hour pulmonary function evaluation. Heart rate and respiratory rate showed a statistically significant but clinically unimportant increase in the albuterol-treated infants. There were no significant differences noted in systolic or diastolic blood pressure. Percent improvement in the pulmonary function indices were calculated from baseline to 48 hours and from baseline to 96 hours for the placebo and albuterol-treated groups. The results indicate that at 48 hours there were statistically significant improvements in total resistance (14.5%), inspiratory resistance (10.8%), and expiratory resistance (12.9%) in the albuterol-treated infants as compared to the spontaneous deterioration of the same values by 25%, 81%, and 11%, respectively, in the placebo-treated infants. In conclusion, oral albuterol therapy of 48 hours duration improved pulmonary resistance without major cardiovascular side effects in ventilator-dependent premature infants. 相似文献
994.
An immunofluorescent study of the distribution of immunoglobulin-containing cells in the normal and the inflamed human gall bladder 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《Gut》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Immunoglobulin-containing cells are present in the normal human gall bladder but they are much less numerous in this site than in the normal intestine. IgA-containing cells predominate in the mucosa but in the muscle layer IgM cells are the more numerous. In both acute and chronic inflammation of the gall bladder there is a marked increase in the number of immunoglobulin-containing cells. In all but the most severe cases of inflammation it is those cells containing IgA which show the greatest increase in numbers, but in severe cases there is a disproportionate rise in the number of IgG- and IgM-containing cells, these latter being possibly derived from the blood. IgA cannot be demonstrated in the epithelial cells of the gall bladder and positive evidence of secretion into the bile of locally produced immunoglobulin is lacking.It is suggested that the concentration of IgA normally present in bile is such that, irrespective of local production, some is derived from the serum or the intestine. 相似文献
995.
996.
Integration of Ultrasound in Undergraduate Medical Education at the California Medical Schools
下载免费PDF全文
![点击此处可从《Journal of ultrasound in medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Alan T. Chiem MD MPH Zachary Soucy DO Vi Am Dinh MD Mikaela Chilstrom MD Laleh Gharahbaghian MD Virag Shah MD Anthony Medak MD Arun Nagdev MD Timothy Jang MD Elena Stark MD PhD Aliasgher Hussain MD Viveta Lobo MD Abraham Pera DO J. Christian Fox MD 《Journal of ultrasound in medicine》2016,35(2):221-233
Since the first medical student ultrasound electives became available more than a decade ago, ultrasound in undergraduate medical education has gained increasing popularity. More than a dozen medical schools have fully integrated ultrasound education in their curricula, with several dozen more institutions planning to follow suit. Starting in June 2012, a working group of emergency ultrasound faculty at the California medical schools began to meet to discuss barriers as well as innovative approaches to implementing ultrasound education in undergraduate medical education. It became clear that an ongoing collaborative could be formed to discuss barriers, exchange ideas, and lend support for this initiative. The group, termed Ultrasound in Medical Education, California (UMeCali), was formed with 2 main goals: to exchange ideas and resources in facilitating ultrasound education and to develop a white paper to discuss our experiences. Five common themes integral to successful ultrasound education in undergraduate medical education are discussed in this article: (1) initiating an ultrasound education program; (2) the role of medical student involvement; (3) integration of ultrasound in the preclinical years; (4) developing longitudinal ultrasound education; and (5) addressing competency. 相似文献
997.
van de Vliet P Onghena P Knapen J Fox KR Probst M van Coppenolle H Pieters G 《Disability and rehabilitation》2003,25(24):1344-1353
Purpose: Exercise has been put forward as a therapeutic means for the treatment of clinical depression.
Methods: In this study, 29 patients, all with diagnosed with mood disorder, completed daily measurements of depression and physical well-being during periods ranging from 77 to 436 days (M = 146.5). Fitness training was added to the treatment after a period and changes before (A-phase) and after (B-phase) the implementation of this training were the subject of investigation. Data were analysed by means of randomization tests with an AB-design and time-series analysis. Replication of the findings was investigated using Fisher's multiplicative method.
Results: Adding fitness training to the treatment of clinical depression does not systematically lead to changes in self-reported feelings of depression on top of benefits that may be due to other treatments.
Conclusion: Since the present findings are not in agreement with previous studies, the absence of statistically significant changes in self-reported feelings of depression is discussed within the complexity of the 'exercise - depression' relationship in inpatient populations. These included the severity of their depression, the potential ceiling effect of a multifaceted treatment programme and the initial increase in depression due to the confrontational nature of the intervention. 相似文献
Methods: In this study, 29 patients, all with diagnosed with mood disorder, completed daily measurements of depression and physical well-being during periods ranging from 77 to 436 days (M = 146.5). Fitness training was added to the treatment after a period and changes before (A-phase) and after (B-phase) the implementation of this training were the subject of investigation. Data were analysed by means of randomization tests with an AB-design and time-series analysis. Replication of the findings was investigated using Fisher's multiplicative method.
Results: Adding fitness training to the treatment of clinical depression does not systematically lead to changes in self-reported feelings of depression on top of benefits that may be due to other treatments.
Conclusion: Since the present findings are not in agreement with previous studies, the absence of statistically significant changes in self-reported feelings of depression is discussed within the complexity of the 'exercise - depression' relationship in inpatient populations. These included the severity of their depression, the potential ceiling effect of a multifaceted treatment programme and the initial increase in depression due to the confrontational nature of the intervention. 相似文献
998.
In research facilities, cats are routinely ignored as a potential source of salmonella infection. Over a period of 18 months, 142 cats received from commercial vendors for use in research were screened for enteric Salmonella. Salmonella was isolated from 15 animals, an incidence of 10.6%. Five (29%) of the 17 shipments contained animals that were positive for Salmonella. The serotypes isolated were Salmonella derby, Salmonella typhimurium, Salmonella anatum, Salmonella enteritidis, and Salmonella bredeney. 相似文献
999.
Vertebral body collapse due to primary amyloidosis 总被引:1,自引:0,他引:1
Primary systemic amyloidosis is a rare cause of vertebral collapse. We describe a patient with extensive systemic involvement who developed collapse of vertebral bodies L1 and L3 in quick succession. Primary amyloid was found on biopsy of L1, but plain radiography, isotope bone scan and magnetic resonance imaging showed no specific features. 相似文献
1000.
B.D. Mitchell B.D. Fox A. Viswanathan A.H. Mitchell S.Z. Powell D.A. Cech 《Journal of clinical neuroscience》2010,17(10):1317-1319
We describe the first patient with an extradural, extramedullary Ewing’s sarcoma tumor mimicking a nerve sheath tumor with no overt evidence of metastasis. A 28-year-old woman with no past medical history presented with a progressive 3-year history of low back pain and right-sided lower extremity radiculopathy after having failed conservative therapies. MRI of the lumbar spine revealed a right-sided enhancing, dumbbell-shaped lesion at the right neural foramen appearing to originate from the L4 nerve root, suspicious for a peripheral nerve sheath tumor or schwannoma. The patient and findings are discussed in the context of the literature, including an update on the relatively recent diagnostic redesignation of the Ewing’s sarcoma family tumors. 相似文献