全文获取类型
收费全文 | 2628篇 |
免费 | 203篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 113篇 |
妇产科学 | 28篇 |
基础医学 | 414篇 |
口腔科学 | 33篇 |
临床医学 | 282篇 |
内科学 | 567篇 |
皮肤病学 | 59篇 |
神经病学 | 295篇 |
特种医学 | 57篇 |
外科学 | 297篇 |
综合类 | 36篇 |
预防医学 | 155篇 |
眼科学 | 63篇 |
药学 | 222篇 |
中国医学 | 18篇 |
肿瘤学 | 185篇 |
出版年
2023年 | 24篇 |
2022年 | 43篇 |
2021年 | 67篇 |
2020年 | 44篇 |
2019年 | 51篇 |
2018年 | 69篇 |
2017年 | 59篇 |
2016年 | 64篇 |
2015年 | 58篇 |
2014年 | 98篇 |
2013年 | 108篇 |
2012年 | 162篇 |
2011年 | 196篇 |
2010年 | 116篇 |
2009年 | 86篇 |
2008年 | 151篇 |
2007年 | 173篇 |
2006年 | 152篇 |
2005年 | 160篇 |
2004年 | 149篇 |
2003年 | 156篇 |
2002年 | 127篇 |
2001年 | 39篇 |
2000年 | 37篇 |
1999年 | 50篇 |
1998年 | 33篇 |
1997年 | 19篇 |
1996年 | 17篇 |
1995年 | 21篇 |
1994年 | 16篇 |
1993年 | 12篇 |
1992年 | 33篇 |
1991年 | 20篇 |
1990年 | 16篇 |
1989年 | 18篇 |
1988年 | 29篇 |
1987年 | 17篇 |
1986年 | 10篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 14篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1973年 | 6篇 |
1972年 | 7篇 |
1971年 | 8篇 |
1970年 | 7篇 |
排序方式: 共有2839条查询结果,搜索用时 15 毫秒
71.
Failure of high doses of propranolol to reduce experimental myocardial ischemic damage 总被引:3,自引:0,他引:3
Myocardial creatine phosphokinase (CPK) activity and myocardial blood flow (MFB, 15 +/- mu microspheres) were measured at 24 hours after ligation of the left anterior descending coronary artery in nine untreated anesthetized dogs, in eight dogs pretreated with intravenous propranolol 5 mg/kg and in eight which had both pretreatment as well as infusion of propranolol (1.25 mg/kg/hour) after occlusion. Loss of CPK activity from the border and center zones of the myocardial infarct was similar in extent in dogs which had pretreatment but no infusion of propranolol as it was in the control group. Loss of CPK from the center zone was greater (P less than 0.005) in dogs receiving pretreatment followed by constant infusion of the drug. Propranolol had no significant effect on collateral blood flow to the border or center zone of the infarct. In separate experiments, there was no important difference in hemodynamic measurements, except a slower heart rate (P less than 0.01), when pretreated dogs were compared with control dogs up to 2 hours after coronary ligation. We conclude that propranolol given in this dose does not influence nyocardial damage, on the basis of regional myocardial blood flow or tissue CPK depletion values at 24 hr after coronary occlusion. 相似文献
72.
73.
74.
AIMS: To determine the percentage of children and young adults who are obese or overweight within different ethnic and socioeconomic groups. METHODS: Secondary analysis of data on 5689 children and young adults aged 2-20 years from the 1999 Health Survey for England. RESULTS: Twenty three per cent of children (n = 1311) were overweight, of whom 6% (n = 358) were obese. More girls than boys were overweight (24% v 22%). Afro-Caribbean girls were more likely to be overweight (odds ratio 1.73, 95% CI 1.29 to 2.33), and Afro-Caribbean and Pakistani girls were more likely to be obese than girls in the general population (odds ratios 2.74 (95% CI 1.74 to 4.31) and 1.71 (95% CI 1.06 to 2.76), respectively). Indian and Pakistani boys were more likely to be overweight (odds ratios 1.55 (95% CI 1.12 to 2.17) and 1.36 (95% CI 1.01 to 1.83), respectively). There were no significant differences in the prevalence of obese and overweight children from different social classes. CONCLUSION: The percentage of children and young adults who are obese and overweight differs by ethnic group and sex, but not by social class. British Afro-Caribbean and Pakistani girls have an increased risk of being obese and Indian and Pakistani boys have an increased risk of being overweight than the general population. These individuals may be at greater combined cumulative risk of morbidity and mortality from cardiovascular disease and so may be a priority for initiatives to target groups of children at particular risk of obesity. 相似文献
75.
Westman E Ambler GR Royle M Peat J Chan A 《Journal of pediatric endocrinology & metabolism : JPEM》1999,12(3):433-442
We aimed to assess the growth, diabetes control, dietary intake and compliance with a gluten-free diet in children with insulin dependent diabetes mellitus (IDDM) and coeliac disease in a major paediatric and adolescent diabetes clinic. Children with IDDM and biopsy-proven coeliac disease aged <18 years were included and compared with IDDM controls matched for age, sex and duration of diabetes. Twenty patients with coeliac disease and IDDM participated (15 female, age 7.4-17.3 yr), with two matched IDDM controls for each (age 6.9-17.4 yr). The prevalence of coeliac disease in this diabetes clinic population was 2.6%. All patients completed a 3 day food record (3DFR) and a 7 day food frequency questionnaire (FFQ) to assess dietary intake and gluten-free compliance. Diabetes control measured by HbA1c was not different between groups or compared to the overall clinic population (8.48 +/- 0.98% for coeliac patients vs 8.87 +/- 1.46 for IDDM controls vs 8.60 +/- 1.30 for overall clinic population aged 5.0-17.9 yr). Height, weight and BMI standard deviation scores were not different between coeliac patients and IDDM controls. No clinically significant differences were found in intake of energy, macronutrients or micronutrients. The proportion of energy intake from carbohydrate, protein and fat was within recommended ranges, except for a higher saturated fat intake. Only 30% of coeliac patients complied with a strict gluten-free diet, but growth parameters were unaffected by dietary compliance. Thus, we found that children and adolescents with coexisting IDDM and coeliac disease have normal growth, equivalent diabetes control and no differences in energy or nutrient intake compared to matched IDDM controls in our clinic population. 相似文献
76.
Huang J Fan G Zhong Y Gatter K Braziel R Gross G Bakke A 《American journal of clinical pathology》2005,123(6):826-832
The diagnosis of B-cell chronic lymphoproliferative disorders is a great challenge when made in a background of polyclonal B cells. We studied the diagnostic usefulness of aberrant CD22 expression for differentiating neoplastic from benign B cells by 4-color flow cytometry. Of 56 cases of B-cell chronic lymphoproliferative disorders, we found that neoplastic cells showed aberrant CD22 expression in 39 (70%) of 56 cases, including chronic lymphocytic leukemia, mantle cell lymphoma, marginal zone lymphoma, hairy cell leukemia, and follicular lymphoma. In 4 cases, monoclonality was detected definitively only by evaluating the immunoglobulin light chain restriction in B cells with aberrant CD22 expression because numerous polyclonal B cells were present. Aberrant CD22 expression is a useful marker for detection of monoclonal B cells admixed with numerous benign polyclonal B cells. 相似文献
77.
Shinichiro Hirose Yukiko Umetani Misato Amitani Rie Hosoi Sotaro Momosaki Jun Hatazawa Antony Gee Osamu Inoue 《Neuroscience letters》2007
The effect of inhibition of glial metabolism by infusion of fluorocitrate (FC, 1 nmol/μl, 2 μl) into the right striatum of the rat brain on the glucose metabolism was studied. Significant increases in [18F]fluorodeoxyglucose ([18F]FDG) uptake (45 min) in the right cerebral cortex and striatum were observed 4 h after the infusion of FC, both as determined by the tissue dissection method and autoradiography. No significant increase in the initial uptake of [18F]FDG (1 min) was seen in the striatum. Pretreatment with dizocilpine (MK-801), an N-methyl-d-aspartate (NMDA) receptor antagonist, reduced [18F]FDG uptake in not only FC infused hemisphere but also in the contralateral hemisphere (saline-infused side). The radioactivity concentrations in plasma at 1, 5 and 45 min after the [18F]FDG injection were not altered by MK-801. This effect of MK-801 on glucose metabolism observed in the rat brain infused with FC was different from previous reports which indicated an increase in glucose metabolism in some areas of normal rat brain. In addition, the enhancement of glucose metabolism in the striatum induced by FC was almost completely abolished by pretreatment with MK-801. In the cerebral cortex, the relative ratio of radioactivity concentration in the right hemisphere to that in the left hemisphere still remained 1.37 (tissue dissection method) or 1.55 (autoradiography), which indicated that MK-801 partially blocked the effect of FC of enhancing glucose metabolism in this region. These results indicate an important role of NMDA-mediated signal transmission on the increase of glucose utilization induced by inhibition of glial metabolism. 相似文献
78.
Chinese medicine has been used to treat a variety of cancer-related conditions. This study aims to examine the prevalence and patterns of Chinese medicine usage by cancer patients. We reviewed articles written in English and found only the Chinese medicine usage from the studies on complementary and alternative medicine (CAM). Seventy four (74) out of 81 articles reported rates of CAM usage ranging from 2.6 to 100%. Acupuncture was reported in 71 out of 81 studies. Other less commonly reported modalities included Qigong (n = 17), Chinese herbal medicine (n = 11), Taichi (n = 10), acupressure (n = 6), moxibustion (n = 2), Chinese dietary therapy (n = 1), Chinese massage (n = 1), cupping (n = 1) and other Chinese medicine modalities (n = 19). This review also found important limitations of the English language articles on CAM usage in cancer patients. Our results show that Chinese medicine, in particular Chinese herbal medicine, is commonly used by cancer patients. Further research is warranted to include studies not written in English. 相似文献
79.
80.
The study examined odour identification ability in healthy older adults at increased risk for developing Alzheimer's disease (AD). We recruited a sample (n = 24) of siblings related to probable AD cases and an age-matched control sample (n = 47). All participants were genotyped for the presence of the ApoE epsilon4 allele. Performance on a simple olfactory task of odour identification was compared according to positive family history of AD and ApoE epsilon4 status. The sibling group showed an odour identification deficit compared to the control group. Whilst there was no independent influence of ApoE epsilon4 status on odour identification, there was a significant interaction between positive family history and ApoE epsilon4 status. Sibling epsilon4 carriers showed the greatest odour identification deficit and their performance was significantly poorer than both the sibling non-epsilon4 carrier and control epsilon4 carrier groups. Odour identification deficits like those reported here are considered to be early cognitive markers of incipient AD. In this respect, these findings support the need to both monitor individuals at increased risk of the disease and introduce olfactory-mediated cognitive tasks into the diagnostic setting. 相似文献