全文获取类型
收费全文 | 60380篇 |
免费 | 5068篇 |
国内免费 | 160篇 |
专业分类
耳鼻咽喉 | 459篇 |
儿科学 | 2090篇 |
妇产科学 | 1454篇 |
基础医学 | 7717篇 |
口腔科学 | 1291篇 |
临床医学 | 6519篇 |
内科学 | 11866篇 |
皮肤病学 | 1019篇 |
神经病学 | 5423篇 |
特种医学 | 2007篇 |
外国民族医学 | 3篇 |
外科学 | 8848篇 |
综合类 | 1055篇 |
一般理论 | 85篇 |
预防医学 | 5738篇 |
眼科学 | 1362篇 |
药学 | 4515篇 |
中国医学 | 133篇 |
肿瘤学 | 4024篇 |
出版年
2022年 | 371篇 |
2021年 | 814篇 |
2020年 | 544篇 |
2019年 | 879篇 |
2018年 | 1112篇 |
2017年 | 803篇 |
2016年 | 850篇 |
2015年 | 1081篇 |
2014年 | 1527篇 |
2013年 | 2283篇 |
2012年 | 3463篇 |
2011年 | 3707篇 |
2010年 | 2102篇 |
2009年 | 1923篇 |
2008年 | 3377篇 |
2007年 | 3659篇 |
2006年 | 3684篇 |
2005年 | 3735篇 |
2004年 | 3537篇 |
2003年 | 3299篇 |
2002年 | 3297篇 |
2001年 | 1174篇 |
2000年 | 1042篇 |
1999年 | 1107篇 |
1998年 | 900篇 |
1997年 | 706篇 |
1996年 | 672篇 |
1995年 | 602篇 |
1994年 | 525篇 |
1993年 | 507篇 |
1992年 | 822篇 |
1991年 | 702篇 |
1990年 | 689篇 |
1989年 | 628篇 |
1988年 | 597篇 |
1987年 | 575篇 |
1986年 | 595篇 |
1985年 | 561篇 |
1984年 | 580篇 |
1983年 | 479篇 |
1982年 | 502篇 |
1981年 | 450篇 |
1980年 | 440篇 |
1979年 | 423篇 |
1978年 | 356篇 |
1977年 | 320篇 |
1976年 | 283篇 |
1975年 | 268篇 |
1974年 | 314篇 |
1973年 | 288篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Alan S Herford 《Journal of oral and maxillofacial surgery》2004,62(9):1082-1087
PURPOSE: This article describes a technique for reconstructing nasal deformities resulting from trauma. Bone harvested from the lateral ramus/body of the mandible is used to provide nasal support for major nasal deformities. PATIENTS AND METHODS: Ten patients underwent repair of their nasal deformities with an autogenous bone graft harvested from the mandible. Primary bone grafting was used to repair a nasal deformity associated with a naso-orbito-ethmoidal fracture in 8 patients. Secondarily, 2 patients underwent placement of a graft for correction of a saddle nose deformity. RESULTS: All patients achieved aesthetic results. There was maintenance of nasal projection and symmetry without displacement of the graft. None of the patients complained of an unnatural hardness of the nasal tip or dorsum. All grafts healed without evidence of infection, dehiscence, or necrosis. CONCLUSION: The lateral ramus/body of the mandible provide an excellent donor site alternative for nasal reconstruction. 相似文献
23.
24.
PROBLEM: Recent developments in providing care to children with emotional and behavioral disorders, especially those with serious emotional disturbance, have included the establishment of systems of care. Guided by a set of principles and values, these systems of care have organized and delivered services to children and families with complex needs. To date, nurses have not had a salient role in systems of care. RESULTS: It is estimated that 20% of American children and adolescents have an emotional or mental disorder. As many as two thirds of these children are not receiving services. Systems of care have been funded to provide services for these children, particularly for the most severely affected. To date, nursing has not had a prominent role in these systems of care. CONCLUSIONS: Based on their knowledge, skills, and holistic approach to care, nurses could better integrate nursing care into systems of care. Possible roles as case managers, primary therapists, in-home interventionists, and in educational programs are suggested. 相似文献
25.
Keith J Murphy Andrew G Foley Alan W O'connell Ciaran M Regan 《Neuropsychopharmacology》2006,31(1):90-100
Recent data suggest that Alzheimer's patients who discontinue treatment with cholinesterase inhibitors have a significantly delayed cognitive decline as compared to patients receiving placebo. Such observations suggest cholinesterase inhibitors to provide a disease-modifying effect as well as symptomatic relief and, moreover, that this benefit remains after drug withdrawal. Consistent with this suggestion, we now demonstrate that chronic administration of tacrine, nefiracetam, and deprenyl, drugs that augment cholinergic function, increases the basal frequency of dentate polysialylated neurons in a manner similar to the enhanced neuroplasticity achieved through complex environment rearing. While both drug-treated and complex environment reared animals continue to exhibit memory-associated activation of hippocampal polysialylated neurons, the magnitude is significantly reduced suggesting that such interventions induce a more robust memory pathway that can acquire and consolidate new information more efficiently. This hypothesis is supported by our findings of improved learning behavior and enhanced resistance to cholinergic deficits seen following either intervention. Furthermore, the level of enhancement of basal neuroplastic status achieved by either drug or environmental intervention correlates directly with improved spatial learning ability. As a combination of both interventions failed to further increase basal polysialylated cell frequency, complex environment rearing and chronic drug regimens most likely enhanced cognitive performance by the same mechanism(s). These findings suggest that improved memory-associated synaptic plasticity may be the fundamental mechanism underlying the disease modifying action of drugs such as cholinesterase inhibitors. Moreover, the molecular and cellular events underpinning neuroplastic responses are identified as novel targets in the search for interventive drug strategies for the treatment of neurodegenerative and neuropsychiatric disorders. 相似文献
26.
27.
28.
Pitfalls in diagnosis of aortic dissection by angiography: Algorithmic approach utilizing CT and MRI
Harold L. Mast David H. Gordon Alan M. Kantor 《Computerized medical imaging and graphics》1991,15(6):431-440
Dissection of the thoracic aorta is a life-threatening event requiring imaging studies to define the level of the tear and the intinmal flap. The “gold standard” has been angiography. This method may fail to demonstrate the dissection, however, due to overlap of the true and false lumens or a very thin flap that is imaged en face rather than tangentially. Computed tomography has a diagnostic accuracy of 95%, but can fail to image the dissection due to technical factors or a thrombosed false hunen. Magnetic resonance imaging requires a hemodynamically stable and cooperative patient. A diagnostic algorithm is proposed for diagnosis of aortic dissection based on renal function and the surgeon's imaging modality preference. 相似文献
29.
Guo-Lin Wei Juri Melnik Jing-Li Luo Alan R. Sanger Karl T. Chuang 《Journal of electroanalytical chemistry (Lausanne, Switzerland)》2005,575(2):183-193
The performances of three widely different cathode materials (Pt, strontium-doped lanthanum manganite (LSM), and NiO) have been compared for use with proton conducting Li2SO4–Al2O3 composite electrolyte, using H2S–air and H2–air fuel cells operating at 600 °C. Surface analysis and electrochemical techniques were used to characterize fresh and used electrode materials. Pt or LSM cathodes each became covered with Li2SO4 and Al2O3 and, as a consequence, the fuel cells showed poor performance. In contrast, the NiO cathode catalyst did not become covered with Li2SO4 and good fuel cell performance was achieved. Exceptionally good current densities of over 100 mA/cm2 and power densities of over 30 mW/cm2 were obtained for H2S–air fuel cells having Mo–Ni–S anode catalysts. Slight agglomeration of NiO particles during fuel cell operation had only a minor effect on performance. 相似文献
30.