全文获取类型
收费全文 | 17362篇 |
免费 | 1136篇 |
国内免费 | 114篇 |
专业分类
耳鼻咽喉 | 267篇 |
儿科学 | 405篇 |
妇产科学 | 293篇 |
基础医学 | 2488篇 |
口腔科学 | 1765篇 |
临床医学 | 1385篇 |
内科学 | 3675篇 |
皮肤病学 | 419篇 |
神经病学 | 1238篇 |
特种医学 | 524篇 |
外科学 | 1831篇 |
综合类 | 137篇 |
一般理论 | 4篇 |
预防医学 | 1970篇 |
眼科学 | 175篇 |
药学 | 1309篇 |
中国医学 | 177篇 |
肿瘤学 | 550篇 |
出版年
2023年 | 152篇 |
2022年 | 416篇 |
2021年 | 657篇 |
2020年 | 449篇 |
2019年 | 549篇 |
2018年 | 686篇 |
2017年 | 568篇 |
2016年 | 539篇 |
2015年 | 697篇 |
2014年 | 869篇 |
2013年 | 976篇 |
2012年 | 1425篇 |
2011年 | 1585篇 |
2010年 | 868篇 |
2009年 | 665篇 |
2008年 | 1019篇 |
2007年 | 1068篇 |
2006年 | 837篇 |
2005年 | 712篇 |
2004年 | 599篇 |
2003年 | 500篇 |
2002年 | 415篇 |
2001年 | 291篇 |
2000年 | 261篇 |
1999年 | 207篇 |
1998年 | 141篇 |
1997年 | 117篇 |
1996年 | 101篇 |
1995年 | 84篇 |
1994年 | 94篇 |
1993年 | 68篇 |
1992年 | 94篇 |
1991年 | 92篇 |
1990年 | 71篇 |
1989年 | 78篇 |
1988年 | 73篇 |
1987年 | 47篇 |
1986年 | 59篇 |
1985年 | 53篇 |
1984年 | 33篇 |
1983年 | 43篇 |
1982年 | 18篇 |
1980年 | 34篇 |
1979年 | 34篇 |
1978年 | 19篇 |
1977年 | 21篇 |
1976年 | 21篇 |
1975年 | 21篇 |
1973年 | 20篇 |
1968年 | 32篇 |
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
41.
M B Ferraz R M Ciconelli P M Araujo L M Oliveira E Atra 《The Journal of hand surgery》1992,17(6):1099-1103
Grip strength is one of the traditional outcome measures commonly used in rheumatoid arthritis trials. This study evaluated the degree of morning variation and the effect of elbow flexion in the assessment of grip strength in patients with rheumatoid arthritis. Grip strength was measured in 37 patients (1987 American Rheumatism Association criteria) at 8, 10, and 12 AM with a sphygmomanometer cuff folded on itself, taped permanently, and inflated to 20 mm Hg, with the elbow flexed at 90 degrees. At 10 AM grip strength was also measured with the elbow flexed at 30 and 130 degrees. Mean values for grip strength at 8, 10, and 12 AM were, respectively, 69, 79, and 83 mm Hg. Mean grip strength values with the elbow flexed at 30, 90, and 130 degrees were, respectively, 78, 79, and 75 mm Hg. There was a statistically significant correlation between grip strength and morning stiffness, grip strength and hand function, and grip strength and number of active joints. In rheumatoid arthritis trials, grip strength should be assessed at the same time of the day. Elbow flexion does not play a role in grip strength measurement. 相似文献
42.
43.
44.
Medullary sponge kidney and congenital hemi-hypertrophy 总被引:2,自引:0,他引:2
45.
46.
Raquel Carreira Ana Duarte Pedro Monteiro Maria Sancha Santos Ana Cristina Rego Catarina R Oliveira Lino M Gon?alves Luís A Providência 《Revista portuguesa de cardiologia》2004,23(11):1447-1455
Ischemia negatively affects mitochondrial function by inducing the mitochondrial permeability transition (MPT). The MPT is triggered by oxidative stress, which occurs in mitochondria during ischemia as a result of diminished antioxidant defenses and increased reactive oxygen species production. It causes mitochondrial dysfunction and can ultimately lead to cell death. Therefore, drugs able to minimize mitochondrial damage induced by ischemia may prove to be clinically effective. We analyzed the effect of carvedilol, a beta-blocker with antioxidant properties, on mitochondrial dysfunction. Carvedilol decreased levels of TBARS (thiobarbituric acid reactive substances), an indicator of oxidative stress, which is consistent with its antioxidant properties. Regarding cell death by apoptosis, although ischemia did increase caspase-8-like activity, there were no changes in caspase-3-like activity, which is activated downstream of caspase-8; this may indicate that the apoptotic cascade is not activated by 60 minutes of ischemia. We conclude that carvedilol protects ischemic mitochondria by preventing oxidative mitochondrial damage, and, by so doing, it may also inhibit the formation of the MPT pore. 相似文献
47.
Calciphylaxis – a topical overview 总被引:3,自引:0,他引:3
G Arseculeratne† AT Evans‡ SM Morley† 《Journal of the European Academy of Dermatology and Venereology》2006,20(5):493-502
'Calciphylaxis', a calcification syndrome associated with ischaemic cutaneous necrosis, is acquired naturally in humans in disease states. It is a life and limb-threatening complication, usually observed in patients with renal disease and secondary hyperparathyroidism, but known to occur in the absence of renal or parathyroid disease. The reported mortality rate, which ranges from 60-80%, relates to wound infection, sepsis and organ failure. It is a small-vessel vasculopathy, which is estimated to occur in about 4% of haemodialysis patients. Clinically, violaceous, reticulate areas of cutaneous necrosis and eschar may be evident, particularly in the extremities. In addition to the clinical picture, a raised calcium phosphorous product, an elevated parathyroid hormone level, radiographic evidence of vessel and soft-tissue calcification and the finding of mural calcification affecting small arteries and arterioles on histopathology help to confirm the diagnosis of this entity which generally has a poor prognosis. A high index of suspicion and an active multidisciplinary management approach, with rigorous attention to wound care and prevention of sepsis, are vital in the management of these patients. In this overview, we discuss the pathophysiology, clinical features and associations, risk factors, diagnosis and management issues relating to calciphylaxis. 相似文献
48.
Sandra Guerra A Teixeira Pinto José Ribeiro José Oliveira José Duarte Jorge Mota 《Revista portuguesa de cardiologia》2003,22(2):167-182
An important aspect of preventive medicine is to identify subjects at risk as soon as possible, so preventive strategies can be introduced at early ages. The justification for this strategy is twofold: firstly, the assumption that children maintain a particular high value of a risk factor for disease throughout life; and secondly, the assumption that lowering the level of the risk factor in early life will have a greater impact on the disease than will risk factor changes in later life. In epidemiology the analysis of such factors over time is referred to as tracking. Tracking analysis has been applied to risk factors for cardiovascular diseases (CVD) in pediatric years. The aims of this study were: I) to analyze the stability of biological risk factors [high blood pressure (BP), high percentage of fat mass (%FM) and high total cholesterol (TC)] and lifestyle risk factors [low physical activity index (PAI)] in isolation; and II) to analyze the stability of zero, one, two or three biological risk factors. There were two evaluations in 692 children and adolescents (325 boys and 367 girls), aged between 8 and 15 years. The quartiles, adjusted for age and gender, were the criterion used to identify subjects with biological risk factors (fourth quartile) and with lifestyle risk factors (first quartile) for CVD. The stability was calculated through the relative frequency of subjects who maintained or changed quartile between the two evaluations. There is stability for biological risk factors as well as for behavioral and/or lifestyle risk factors. However, the highest stability is seen in biological risk factors. 相似文献
49.
L A D'Albuquerque A de Oliveira e Silva T Genzini M P de Miranda F Roldan-Molina 《Arquivos de gastroenterologia》1991,28(4):124-131
In the period of January 1978 to October 1988, 32 Le Veen shunts (LVS) were implanted in 20 patients, out of which 16 were alcoholic cirrhotics and 4 postnecrotic cirrhotics. In the present study, we correlated preoperative laboratory data of these patients with their postoperative evolution, comparing the clinical results of patients who survived more than 30 days (13 patients = 65%) with the results of those who died within the same period (7 patients = 35%). For that matter, 14 laboratory tests were performed in order to measure the serum levels of hematocrit, hemoglobin, urea, creatinine, sodium, potassium, bilirubin, albumin, AST, ALT, alkaline phosphatase, fibrinogen, gamma GT and prothrombin activity. After statistical analysis, we observed that 6 of the 14 tests performed could be considered of prognostic value in the following decreasing order of importance: fibrinogen, alkaline phosphatase, prothrombin activity, urea, gamma GT and bilirubin. We observed that all the 7 patients who died prematurely presented 3 or more of these levels altered, when compared with standard values. Based on these data, we concluded that serum levels of fibrinogen, alkaline phosphatase, urea, gamma GT, bilirubin and activity of prothrombin proved to be important factors in determining the prognosis of immediate survival in cirrhotic patients who underwent LVS implantation. We also concluded that when 3 or more of these factors are altered, the implant of LVS is contraindicated, whatever clinical criteria for indication and contraindication were taken into account. 相似文献
50.
Luciana Dias de Oliveira Elsa Regina Justo Giugliani Lílian Córdova do Espírito Santo Maristela Cavalheiro Tamborindeguy Fran?a Enilda Maria Lara Weigert Celina Valderez Feijó Kohler Ana Lúcia de Lourenzi Bonilha 《Journal of human lactation》2006,22(3):315-321
This randomized clinical trial compared frequencies of exclusive breastfeeding and lactation-related problems during the first 30 days among 74 mothers who received a 30-minute counseling session on breastfeeding technique in the maternity ward, and 137 controls. The frequency of exclusive breastfeeding among mothers who had received intervention was similar to controls by 7 days (79.7% vs 82.5%, respectively) and 30 days (60.8% vs 53.3%). There was no difference between groups in the frequency of sore nipples at 7 and 30 days, in breast engorgement and mastitis, and in the quality of breastfeeding technique at 30 days. Therefore, a single intervention at maternity was not sufficient to improve breastfeeding technique, increase exclusive breastfeeding rates, and reduce the incidence of breastfeeding problems during the first month. 相似文献