全文获取类型
收费全文 | 17460篇 |
免费 | 1004篇 |
国内免费 | 112篇 |
专业分类
耳鼻咽喉 | 265篇 |
儿科学 | 384篇 |
妇产科学 | 307篇 |
基础医学 | 2494篇 |
口腔科学 | 1771篇 |
临床医学 | 1464篇 |
内科学 | 3605篇 |
皮肤病学 | 419篇 |
神经病学 | 1275篇 |
特种医学 | 492篇 |
外科学 | 1846篇 |
综合类 | 65篇 |
一般理论 | 4篇 |
预防医学 | 1967篇 |
眼科学 | 178篇 |
药学 | 1303篇 |
2篇 | |
中国医学 | 183篇 |
肿瘤学 | 552篇 |
出版年
2024年 | 60篇 |
2023年 | 159篇 |
2022年 | 429篇 |
2021年 | 650篇 |
2020年 | 448篇 |
2019年 | 547篇 |
2018年 | 688篇 |
2017年 | 550篇 |
2016年 | 528篇 |
2015年 | 696篇 |
2014年 | 844篇 |
2013年 | 948篇 |
2012年 | 1416篇 |
2011年 | 1591篇 |
2010年 | 846篇 |
2009年 | 665篇 |
2008年 | 1021篇 |
2007年 | 1052篇 |
2006年 | 825篇 |
2005年 | 715篇 |
2004年 | 591篇 |
2003年 | 506篇 |
2002年 | 417篇 |
2001年 | 285篇 |
2000年 | 263篇 |
1999年 | 214篇 |
1998年 | 136篇 |
1997年 | 135篇 |
1996年 | 99篇 |
1995年 | 85篇 |
1994年 | 86篇 |
1993年 | 69篇 |
1992年 | 98篇 |
1991年 | 96篇 |
1990年 | 67篇 |
1989年 | 83篇 |
1988年 | 71篇 |
1987年 | 61篇 |
1986年 | 54篇 |
1985年 | 52篇 |
1984年 | 35篇 |
1983年 | 43篇 |
1982年 | 19篇 |
1981年 | 19篇 |
1980年 | 35篇 |
1979年 | 31篇 |
1978年 | 18篇 |
1977年 | 27篇 |
1973年 | 21篇 |
1968年 | 33篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
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
12.
13.
Medullary sponge kidney and congenital hemi-hypertrophy 总被引:2,自引:0,他引:2
14.
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
15.
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
16.
17.
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
18.
Effect of two preventive programs on oral health knowledge and habits among Brazilian schoolchildren
Yvonne A. P. Buischi Per Axelsson Luciene B. Oliveira Marcia P. A. Mayer Per Gjermo 《Community dentistry and oral epidemiology》1994,22(1):41-46
Abstract – The effect upon dental health knowledge and dental health behavior of a comprehensive and a less comprehensive preventive program was compared in a 3-yr follow up study. The comprehensive program included active participation of the students and parental involvement. The study group consisted of 186 Brazilian schoolchildren 13 yr of age at the start of the program. A reference group from another school of similar socioeconomic level was included in the analyses. The data were collected from questionnaires filled in by the children under surveillance after the completion of the program. Significant differences in knowledge as well as in reported behavior were observed. The children enrolled in the comprehensive program in general scored higher in dental health knowledge than did those in the less comprehensive program. However, the latter group of children seemed to have acquired more correct knowledge during the period than had the control and reference children. Similar results were obtained concerning reported dental health behavior. 相似文献
19.
Camila Oliveira Rodini Flávia Sirotheau Corrêa Pontes Hélder Ant?nio Rebelo Pontes Paulo Sérgio da Silva Santos Marina Gallottini Magalh?es Décio Santos Pinto 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(4):e50-e55
Leiomyosarcoma of the oral cavity is a very rare tumor associated with aggressive clinical behavior and low survival. In this paper, we report 2 cases of leiomyosarcoma, affecting the gingival mucosa of a 54-year-old female and the maxillary bone of a 63-year-old male. Histologically, the tumors were composed of variably oriented fascicles of spindle-shaped cells with cigar-shaped nuclei and eosinophilic cytoplasm. The lesions were treated by surgical resection. Immunoreactivity to anti-vimentin, anti-smooth muscle actin, anti-desmin, anti-laminin, and anti-muscle-specific actin antibodies were found; conversely, the tumor cells were negative for anti-S100 and AE1/AE3 proteins. This report emphasizes the role of immunohistochemical study for correct diagnosis of leiomyosarcoma. 相似文献
20.
Anna Letícia Soares Marinez de Oliveira Sousa Luci Maria Dusse Ana Paula Salles Moura Fernandes Marcelo Carvalho Lasmar Bethania Alves Novelli Geralda de Fátima Guerra Lages Maria das Gra?as Carvalho 《Blood coagulation & fibrinolysis》2007,18(5):395-399
This study aimed to investigate whether endothelial cells are damaged and to evaluate fibrinolytic system function in patients with type 2 diabetes. For this proposal, plasma levels of von Willebrand factor (an endothelial marker of injury), homocysteine (an inductor of endothelial injury), D-dimer (a marker of coagulation cascade activation) and plasminogen activator inhibitor-1 (a fibrinolysis marker) were measured in individuals with both type 2 diabetes and high blood pressure, with type 2 diabetes, with high blood pressure and in healthy control individuals. No significant differences among groups were observed for von Willebrand factor and homocysteine plasma levels. The type 2 diabetes and high blood pressure group presented a significant difference to the other groups for D-dimer and also presented high values for plasminogen activator inhibitor-1. The high blood pressure group and type 2 diabetes group presented separately higher values of plasminogen activator inhibitor-1 compared with the control group. High levels of D-dimer and plasminogen activator inhibitor-1 in patients with type 2 diabetes and high blood pressure with normoalbuminuria therefore indicate a state of hypercoagulability and hypofibrinolysis, despite no evident microvascular injury supported by normal levels of von Willebrand factor and homocysteine. 相似文献