首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3022篇
  免费   132篇
  国内免费   16篇
耳鼻咽喉   34篇
儿科学   55篇
妇产科学   52篇
基础医学   361篇
口腔科学   416篇
临床医学   197篇
内科学   750篇
皮肤病学   33篇
神经病学   249篇
特种医学   63篇
外科学   405篇
综合类   19篇
预防医学   232篇
眼科学   36篇
药学   173篇
中国医学   21篇
肿瘤学   74篇
  2024年   3篇
  2023年   34篇
  2022年   83篇
  2021年   166篇
  2020年   77篇
  2019年   116篇
  2018年   150篇
  2017年   84篇
  2016年   96篇
  2015年   131篇
  2014年   154篇
  2013年   182篇
  2012年   287篇
  2011年   301篇
  2010年   162篇
  2009年   118篇
  2008年   181篇
  2007年   194篇
  2006年   182篇
  2005年   132篇
  2004年   104篇
  2003年   93篇
  2002年   69篇
  2001年   11篇
  2000年   5篇
  1999年   8篇
  1998年   6篇
  1997年   2篇
  1996年   5篇
  1995年   3篇
  1994年   3篇
  1991年   3篇
  1989年   4篇
  1987年   1篇
  1985年   1篇
  1982年   1篇
  1981年   2篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
  1977年   2篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1964年   1篇
  1963年   1篇
  1962年   1篇
  1936年   2篇
  1935年   1篇
  1934年   1篇
排序方式: 共有3170条查询结果,搜索用时 15 毫秒
11.
We investigated the effects of oral L-glutamine (Gln) supplementation, associated or not with physical exercises, in control of glycemia, oxidative stress, and strength/power of knee muscles in elderly women. Physically active (n = 21) and sedentary (n = 23) elderly women aged 60 to 80 years were enrolled in the study. Plasma levels of D-fructosamine, insulin, reduced (GSH) and oxidized (GSSG) glutathione, iron, uric acid, and thiobarbituric acid-reactive substances (TBARs) (lipoperoxidation product), as well as knee extensor/flexor muscle torque peak and average power (isokinetic test), were assessed pre- and post-supplementation with Gln or placebo (30 days). Higher plasma D-fructosamine, insulin, and iron levels, and lower strength/power of knee muscles were found pre-supplementation in the NPE group than in the PE group. Post-supplementation, Gln subgroups showed higher levels of GSH, GSSG, and torque peak, besides lower D-fructosamine than pre-supplementation values. Higher muscle average power and plasma uric acid levels were reported in the PE + Gln group, whereas lower insulin levels were found in the NPE + Gln than pre-supplementation values. TBARs levels were diminished post-supplementation in all groups. Gln supplementation, mainly when associated with physical exercises, improves strength and power of knee muscles and glycemia control, besides boosting plasma antioxidant capacity of elderly women.  相似文献   
12.
Lasers in Medical Science - Photobiomodulation therapy (PBMT) has been indicated for enforcement on healing skin wounds. This study evaluated the effects of PBMT on the healing of skin wounds...  相似文献   
13.
Background/PurposeThe aim of the study was to evaluate the postoperative quality of life (QoL) of patients who underwent minimally invasive repair of pectus excavatum (MIRPE) with a newly designed bar and bar stabilizers.MethodsWe conducted a prospective randomized study in which patients were operated either with standard perpendicular stabilizers (control group) or with the newly designed oblique stabilizers (intervention group). All patients were evaluated 6 months after the operation with the Pectus Excavatum Evaluation Questionnaire (PEEQ).ResultsThere were 16 patients in the control group and 14 in the intervention group. Mean age was 17 (SD: 3.3, range 14–27) years. There were no demographic differences between groups. Two patients in the control group and one in the intervention group were repaired with two bars instead of one. There was one reoperation in each group. There was a significant difference between the pre- and postoperative scores, in both groups, in the patient body image domain (control group: 9.5 to 3; p < 0.01; intervention group 10 to 3; p < 0.01), as well as in the psychosocial domain (control group: 13.5 to 24, p < 0.01; intervention group: 15 to 24, p < 0.01). With regards to the patients' perception of physical difficulties before and after MIRPE, the difference between pre- and postoperative scores was greater in the intervention group (8 to 12, p < 0.01) than in the control group (10 to 11, p = 0.04). The mean length of stay was 4.5 and 5 days in the intervention group and the control group, respectively.ConclusionOur study showed that patients who underwent MIRPE with the newly designed bars and stabilizers had non-inferior outcomes than patients reported in the literature who underwent MIRPE with standard bars and stabilizers. We found slightly better outcomes in patients in the intervention group compared to the control group, but larger studies will be needed to confirm if those differences are statistically significant.Level of evidenceII  相似文献   
14.
Intestinal failure is a condition in which inadequate digestion or absorption of fluid, electrolytes, and nutrients leads to dehydration or malnutrition. The most common cause of intestinal failure is short bowel syndrome (SBS) defined as <200 cm of functional small intestine. SBS may result from congenital abnormalities or from surgical resection. For the past 3 decades, patients with severe SBS were managed with home parenteral nutrition (HPN). With the emergence of new therapies, the clinician now has multiple options to treat these patients. These include intestinal rehabilitation regimens whereby patients are treated with specialized oral diets, soluble fiber, oral rehydration solutions (ORS), and trophic factors to enhance absorption. There are also a variety of surgical techniques available to preserve intestinal length. Small bowel and multivisceral transplantation has evolved during the last decade to be a valid therapeutic option for those patients who cannot be rehabilitated or who fail HPN. These are interrelated services designed to offer the patient the best therapeutic options to meet their individual needs. This article reviews the principles associated with the nutrition management of this very complex and diverse group of patients.  相似文献   
15.
Brazil is blessed with a great biodiversity, which constitutes one of the most important sources of biologically active compounds, even if it has been largely underexplored. As is the case of the Amazon and Atlantic rainforests, the Brazilian marine fauna remains practically unexplored in the search for new biologically active natural products. Considering that marine organisms have been shown to be one of the most promising sources of new bioactive compounds for the treatment of different human diseases, the 8000 km of the Brazilian coastline represents a great potential for finding new pharmacologically active secondary metabolites. This review presents the status of marine natural products chemistry in Brazil, including results reported by different research groups with emphasis on the isolation, structure elucidation, and evaluation of biological activities of natural products isolated from sponges, ascidians, octocorals, and Opistobranch mollusks. A brief overview of the first Brazilian program on the isolation of marine bacteria and fungi, directed toward the production of biologically active compounds, is also discussed. The current multidisciplinary collaborative program under development at the Universidade de S?o Paulo proposes to establish a new paradigm toward the management of the Brazilian marine biodiversity, integrating research on the species diversity, ecology, taxonomy, and biogeography of marine invertebrates and microorganisms. This program also includes a broad screening program of Brazilian marine bioresources, to search for active compounds that may be of interest for the development of new drug leads.  相似文献   
16.
17.
The occurrence of complications during pregnancy depends less on the degree of human development than differences in the way complications in pregnancy are detected and managed. It is the quick diagnosis and correct management that really contribute to the enormous differences in maternal mortality ratios between countries and regions. Understanding of the determinants of maternal mortality may be improved by studying cases of severe maternal morbidity. In this paper, various approaches to the concept of severe maternal morbidity and near-misses are discussed, and the relationship between these and maternal deaths. Although no consensus has been reached on a strict definition of near-miss or severe maternal morbidity, we show that the definitions used may be tailored to support diverse objectives, including monitoring progress, epidemiological surveillance and auditing of health care. We conclude that the versatility of the concept, the greater frequency of cases available for study and the possibility of interviewing the survivors of severe complications all support the value of studying severe maternal morbidity to help guide local efforts to reduce maternal mortality. Although this may almost be a reality in developed countries, it continues to represent an important and difficult challenge to overcome in places where its benefits would be most evident.  相似文献   
18.
19.
ObjectiveTo estimate the nutritional risk in children 2 to 6 y old.MethodsThe sample consisted of 3058 children enrolled in public and private schools in nine Brazilian cities. The assessment of nutrient intake was based on 1-d data combining direct individual weighing of foods and a food diary. A second evaluation of food consumption was conducted in a subsample to estimate the usual intake.ResultsThere was low prevalence of inadequate intake of vitamin B6 (<0.001%), riboflavin (<0.001%), niacin (<0.001%), thiamin (<0.001%), folate (<0.001%), phosphorus (<0.1%), magnesium (<0.1%), iron (<0.5%), copper (<0.001%), zinc (<0.5%), and selenium (<0.001%). However, 22% of children younger than 4 y and 5% of children older than 4 y consumed fiber quantities larger than the adequate intake. Approximately 30% of the sample consumed more saturated fat than recommended. The prevalence of inadequate vitamin E intake ranged from 15% to 29%. More than 90% of the children had an inadequate vitamin D intake. In children older than 4 y, the prevalence of inadequate calcium intake was approximately 45%. Sodium intake was higher than the upper intake level in 90% of children younger than 4 y and 73% of children older than 4 y.ConclusionsThe prevalence of inadequate dietary intake was low for most nutrients. However, fiber, calcium, and vitamin D and E intakes were lower than recommended. Moreover, children consumed large amounts of sodium and saturated fat.  相似文献   
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号