全文获取类型
收费全文 | 31335篇 |
免费 | 2723篇 |
国内免费 | 85篇 |
专业分类
耳鼻咽喉 | 200篇 |
儿科学 | 1127篇 |
妇产科学 | 980篇 |
基础医学 | 4222篇 |
口腔科学 | 499篇 |
临床医学 | 3945篇 |
内科学 | 5984篇 |
皮肤病学 | 374篇 |
神经病学 | 3363篇 |
特种医学 | 844篇 |
外国民族医学 | 1篇 |
外科学 | 2884篇 |
综合类 | 534篇 |
一般理论 | 48篇 |
预防医学 | 4183篇 |
眼科学 | 697篇 |
药学 | 2212篇 |
中国医学 | 36篇 |
肿瘤学 | 2010篇 |
出版年
2023年 | 237篇 |
2022年 | 306篇 |
2021年 | 615篇 |
2020年 | 424篇 |
2019年 | 685篇 |
2018年 | 746篇 |
2017年 | 563篇 |
2016年 | 598篇 |
2015年 | 673篇 |
2014年 | 959篇 |
2013年 | 1449篇 |
2012年 | 2033篇 |
2011年 | 2124篇 |
2010年 | 1163篇 |
2009年 | 1088篇 |
2008年 | 1736篇 |
2007年 | 1979篇 |
2006年 | 1874篇 |
2005年 | 1804篇 |
2004年 | 1795篇 |
2003年 | 1637篇 |
2002年 | 1532篇 |
2001年 | 492篇 |
2000年 | 452篇 |
1999年 | 427篇 |
1998年 | 343篇 |
1997年 | 289篇 |
1996年 | 235篇 |
1995年 | 237篇 |
1994年 | 199篇 |
1993年 | 204篇 |
1992年 | 298篇 |
1991年 | 297篇 |
1990年 | 267篇 |
1989年 | 255篇 |
1988年 | 204篇 |
1987年 | 233篇 |
1986年 | 188篇 |
1985年 | 217篇 |
1984年 | 186篇 |
1983年 | 204篇 |
1982年 | 179篇 |
1981年 | 175篇 |
1980年 | 151篇 |
1979年 | 165篇 |
1976年 | 152篇 |
1975年 | 141篇 |
1974年 | 179篇 |
1973年 | 165篇 |
1972年 | 141篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Gaston R Vergara William F Wallace Kenneth R Bennett 《Catheterization and cardiovascular interventions》2007,69(2):300-302
Thromboembolic disease accounts for thousands of hospitalizations every year in the US. Its primary management consists of anticoagulation. However, in certain instances this may be contraindicated or not sufficient. Mechanic occlusion of the inferior vena cava (IVC) becomes then a viable alternative. In this case a 35-year-old man presented with a saddle pulmonary embolus but was unable to be anticoagulated due to intestinal bleed. A removable IVC filter was then placed. The filter spontaneously migrated into the right atrium causing severe tricuspid regurgitation, perforation of the atrial wall, and cardiac tamponade. The device was successfully retrieved percutaneously and the patient discharged from the hospital in stable condition. This case illustrates the potentially lethal complications associated with the use of IVC filters, as well as the possibility to percutaneously recover them from within the right atrium. 相似文献
102.
Crystal deposits in the human intervertebral disc: implications for disc degeneration. 总被引:1,自引:0,他引:1
BACKGROUND CONTEXT: Although crystal deposition in cartilage and synovial fluid has received much attention, crystal formation and the role that crystal deposits play are virtually unexplored in the intervertebral disc. In articular cartilage matrix, crystal deposits are associated with altered extracellular matrix (ECM) and cell phenotypic features, but crystal deposition in the human intervertebral disc has received much less attention. PURPOSE: To determine the incidence of crystal deposits in the annulus and to evaluate associated disc cell and ECM features. STUDY DESIGN/SETTING: Human intervertebral disc annulus tissue was obtained in a prospective study of the presence of crystals in the disc ECM. Human Subjects Institutional Review Board approved experimental studies. PATIENT SAMPLE: Two hundred eight sequential disc specimens were submitted from surgical disc procedures performed on individuals with herniated discs, degenerative disc disease, or recurrent disc herniation. During this same time period, three disc specimens were received from nonsurgical donors and added to the study population. OUTCOME MEASURES: Histologic features with special attention to crystal deposition. METHODS: Specimens were processed undecalcified and examined for the histologic presence of crystal deposits and ECM features around the crystals. RESULTS: The proportion of specimens containing crystals was determined to be 14.7%; crystals displayed varying sizes, morphology, and polarized light birefringence features. Pyrophosphate crystals were most common, but oxalate-like crystals were also present. ECM in crystal regions showed previously recognized alterations. CONCLUSIONS: This study shows that the incidence of crystal deposits in discs is approximately 15% and is thus a relatively common occurrence. These data are important because masses of crystals not only disrupt disc ECM but may also accelerate preexisting degenerative changes via an elevation in matrix metalloproteinases (as previously recognized in cartilage). Because failure of the structural integrity of the disc can result in annular tears and subsequent disc herniation, the mechanisms of crystal formation and the relationship between crystals and disc degeneration merit further investigations. 相似文献
103.
Lorraine N Clark Eneli Haamer Helen Mejia-Santana Juliette Harris Suzanne Lesage Alexandra Durr Sabine Janin Bs Katja Hedrich Elan D Louis Lucien J Cote Howard Andrews Stanley Fahn Cheryl Waters Blair Ford Steven Frucht William Scott Christine Klein Alexis Brice Hanno Roomere Ruth Ottman Karen Marder 《Movement disorders》2007,22(7):932-937
Parkin mutations account for the majority of familial and sporadic early onset Parkinson's disease (EOPD) cases with a known genetic association. More than 100 mutations have been described in the Parkin gene that includes homozygous, compound heterozygous, and single heterozygous mutations. We have designed a Parkin mutation genotyping array (gene chip) that includes published Parkin sequence variants and allows their simultaneous detection. The chip was validated by screening 85 PD cases and 47 controls previously tested for Parkin mutations. Similar genotyping microarrays have been developed for other genetically heterogeneous diseases including age-related macular degeneration. Here, we show the utility of a genotyping array for Parkinson's disease by analysis of 60 subjects from the Genetic Epidemiology of Parkinson Disease (GEPD) study that includes 15 early-onset PD case probands and 45 relatives. 相似文献
104.
Sharon A Cook Robert Rosser Helen Toone M Ian James Peter Salmon 《Journal of plastic, reconstructive & aesthetic surgery》2006,59(1):54-64
PURPOSE: Elective cosmetic surgery is expanding in the UK in both the public and private sectors. Because resources are constrained, many cosmetic procedures are being excluded within the National Health Service. If guidelines on who can receive such surgery are to be evidence-based, information is needed about the level of dysfunction in patients referred for elective surgery and whether this is related to their degree of physical abnormality. METHOD: Consecutive patients referred to a regional plastic surgery and burns unit for assessment for elective cosmetic surgery completed standardised measures of physical and psychosocial dysfunction, and indicated their perception of the degree of their abnormality and their preoccupation with it. We distinguished between patients referred for physical reasons or appearance reasons only, and compared levels of physical and psychosocial dysfunction in each with published values for community and clinical samples. Surgeons indicated patients' degree of objective abnormality, and we identified the relationship of dysfunction with perceived and objective abnormality and preoccupation. RESULTS: Whether patients sought surgery for physical or appearance reasons, physical function was normal. Those seeking surgery for appearance reasons only had moderate psychosocial dysfunction, but were not as impaired as clinical groups with psychological problems. Patients seeking the correction of minor skin lesions for purely appearance reasons reported excellent physical and psychosocial function. Level of function was related (negatively) to patients' preoccupation with abnormality rather than to their perceived or objective abnormality. CONCLUSIONS: In general, patients referred for elective cosmetic surgery did not present with significant levels of dysfunction. Moreover, levels of functioning were related to preoccupation rather than to objective abnormality. Therefore, for most patients, whether surgical treatment is generally appropriate is questionable. Future guidelines must seek to identify the small minority who do have a clinical need for surgery. 相似文献
105.
The intra-operative histological assessment of fresh tissue can provide valuable diagnostic information and guide surgical
management, however, even a limited exposure to standard fixation agents can potentially compromise analysis. Defined handling
strategies should exist to facilitate the receipt of all specimens, in their optimal state, by the laboratory. 相似文献
106.
107.
108.
109.
Changes in the design of hospital wards have usually been determined by architects and members of the nursing and medical professions, the views and preferences of patients have seldom been sought directly The Hospital Anxiety and Depression scale and the Disturbance Due to Hospital Noise questionnaire were administered to 64 female patients on bay and Nightingale wards together with a questionnaire designed for this study Perceptions of social and physical factors of ward design were examined, and their relationship to psychological well-being and sleep patterns The results show that the bay ward seemed to offer a more favourable environment for patients but some of the disadvantages of bay wards are balanced by better staffing levels and better and more modern facilities Visibility to nurses was lower on the bay ward The Nightingale ward was perceived as significantly noisier than the bay ward and noise levels were significantly correlated to anxiety scores Paradoxically the increase in noise levels appeared to improve the perceived level of privacy on the Nightingale ward Seventy-five per cent of patients were found to prefer the bay ward design, and since neither design appears to have major disadvantages their continued introduction should be encouraged However, recommendations are made concerning the optimizing of patients' well-being within the bay ward setting 相似文献
110.