全文获取类型
收费全文 | 23185篇 |
免费 | 2208篇 |
国内免费 | 547篇 |
专业分类
耳鼻咽喉 | 131篇 |
儿科学 | 1181篇 |
妇产科学 | 1000篇 |
基础医学 | 2406篇 |
口腔科学 | 578篇 |
临床医学 | 1908篇 |
内科学 | 2784篇 |
皮肤病学 | 285篇 |
神经病学 | 1726篇 |
特种医学 | 704篇 |
外国民族医学 | 2篇 |
外科学 | 1439篇 |
综合类 | 2740篇 |
一般理论 | 3篇 |
预防医学 | 3680篇 |
眼科学 | 719篇 |
药学 | 2720篇 |
16篇 | |
中国医学 | 898篇 |
肿瘤学 | 1020篇 |
出版年
2024年 | 61篇 |
2023年 | 338篇 |
2022年 | 712篇 |
2021年 | 1040篇 |
2020年 | 937篇 |
2019年 | 858篇 |
2018年 | 795篇 |
2017年 | 921篇 |
2016年 | 955篇 |
2015年 | 875篇 |
2014年 | 1474篇 |
2013年 | 1759篇 |
2012年 | 1260篇 |
2011年 | 1416篇 |
2010年 | 1138篇 |
2009年 | 1052篇 |
2008年 | 989篇 |
2007年 | 940篇 |
2006年 | 901篇 |
2005年 | 804篇 |
2004年 | 634篇 |
2003年 | 586篇 |
2002年 | 523篇 |
2001年 | 437篇 |
2000年 | 354篇 |
1999年 | 350篇 |
1998年 | 305篇 |
1997年 | 305篇 |
1996年 | 268篇 |
1995年 | 234篇 |
1994年 | 255篇 |
1993年 | 214篇 |
1992年 | 224篇 |
1991年 | 198篇 |
1990年 | 181篇 |
1989年 | 184篇 |
1988年 | 164篇 |
1987年 | 133篇 |
1986年 | 130篇 |
1985年 | 166篇 |
1984年 | 124篇 |
1983年 | 90篇 |
1982年 | 100篇 |
1981年 | 80篇 |
1980年 | 96篇 |
1979年 | 81篇 |
1978年 | 62篇 |
1977年 | 65篇 |
1976年 | 50篇 |
1975年 | 43篇 |
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
61.
《The Journal of arthroplasty》2021,36(12):3825-3830
BackgroundDemographic factors, including age, sex, body mass index (BMI), race, and ethnicity have great effects on the outcomes of patients undergoing total joint arthroplasty. A portion of this data is included in nearly every study, but the completeness with which it is reported is variable. The purpose of this study is to investigate the frequency at which demographic information is reported and analyzed through formal statistical methods in randomized controlled trials (RCTs) published in the Journal of Arthroplasty (JOA).MethodsA systematic review was conducted of RCTs published in JOA between 2015 and 2019. For each study, we determined if age, sex, weight, height, BMI, race, and ethnicity were reported and/or analyzed. The overall frequency was assessed, along with the rates of reporting by individual year. Studies were evaluated using Cochrane risk-of-bias tool.ResultsAge (96.7%), sex (96.7%), and BMI (80.4%) were reported by the majority of studies. There was very little information provided regarding race (6.2%) and ethnicity (3.8%); although both were reported at the highest frequency in 2019, the final year of articles reviewed. Sex was the most frequently analyzed variable at 11.5%. Only 1 study (0.5%) analyzed ethnicity and no studies analyzed race.ConclusionAlthough age, sex, and BMI are reported at a high rate, RCTs published in JOA rarely reported information on patient race and ethnicity. Demographics were infrequently included as part of statistical analysis. The importance of this information should be recognized and included in the analysis and interpretation of future studies. 相似文献
62.
63.
64.
Summary The genetic polymorphism of transferrin (Tf) was studied in a sample of 385 healthy unrelated subjects of both sexes resident in the province of Cádiz (southern Spain). Isoelectric focusing was carried out in polyacrylamide gels, followed by staining with Coomassie Blue R250. The gene frequencies obtained were as follows: Tf C1, 0.7922; Tf C2, 0.1883; Tf C3, 0.0195. 相似文献
65.
Age of onset heterogeneity in Alzheimer's disease families was modelled by allowing for different liability classes for affected individuals according to their age of onset when calculating lod scores to chromosome 21 and chromosome 19 markers. Linkage to chromosome 21 was supported in the Boston data set, and the method of age correction did not greatly change the lod scores when only affected individuals were analyzed. The location of a gene on chromosome 19 for late age of onset illness was affected by the assumptions about early onset individuals. © 1993 Wiley-Liss, Inc. 1 This article is a US Government work and, as such, is in the public domain in the United States of America. 相似文献
66.
Objective To analyse the relationship between age and treatment with captopril after acute myocardial infarction (AMI). Methods In a randomized trial, 822 patients with a first AMI received conventional medic al treatment, including intravenous thrombolytic therapy and oral aspirin or metoprolol, and then were randomly allocated to captopril [dosage fr om the first 6.25 mg to 25 mg/t.i.d, 209 younger patients (≤64 years), 269 elderly patients (65-75 years)] or conventional treatment only (131 younger p atients, 213 elderly). Survival in the four groups was calculated with the Kapl an-Meier method. Multivariate analysis was performed to understand the degree that multi-variables (including age) affect survival in patients taking captopr il in the hospital or during long term follow-up. Results The survival of patients who took captopril correlated significantly with age ( P<0.001). The survival of the elderly patients on captopril treatment did increase (P<0.0001), but not of the younger ones (P>0.05) during hosp italization. During follow-up, the survival of patients who took captopril cor related insignificantly with age (P>0.05), but both the elderly and the you n ger patients have good survival rates (all P<0.01) and lower cardiac events (all P<0.01) when they took captopril.Conclusions Captopril exerts a weak effect on the younger patients but a beneficial effect o n the elderly patients during hospitalization after AMI. However, there is no d ifference between the younger and the elderly in the prognosis, both having good survival and lower cardiac events when they take captopril long term during fol low-up. 相似文献
67.
Judith K. Brown Perla Subbaiah Therese Sarah 《Journal of cross-cultural gerontology》1994,9(2):231-254
Our cross-cultural study of the relationship between older women and their younger female kin examines women's hierarchies based on age and focuses on the exercise of authority by women, when such authority is traditional and accepted. Data were collected for two world-wide samples each consisting of 30 societies, varying in complexity, subsistence base, geographic location, and in customs related to women's lives. Three hypotheses were tested. The findings, which are statistically significant, suggest that the relationships between older women and their younger female kin are patterned and predictable, determined by the role of women in subsistence activities, by rules for post-marital residence, and by descent.When domination can only be exercised... directly, between one person and another, it can not take place overtly and must be disguised under the veil of enchanted relationships, the official model of which is presented by the relations between kinsmen.The gentle, invisible form of violence, which is never recognized as such... can not fail to be seen as the most economical mode of domination...The system is such that the dominant agents have a vested interest in virtue. (Bourdieu 1991191, 192, 194) 相似文献
68.
Histological and enzyme histochemical parameters for the age estimation of human skin wounds 总被引:6,自引:0,他引:6
P. Betz 《International journal of legal medicine》1994,107(2):60-68
Routine histological staining techniques form the basis of a forensic age estimation of human skin wounds and the determination of vitality is aided by the detection of neutrophilic granulocytes which appear earliest about 20–30 min after wounding. A clear granulocyte infiltration and a significant increase in the number of macrophages indicates a post infliction interval of at least several hours. Macrophages containing incorporated particles such as lipophages, erythrophages or siderophages appear earliest at a wound age of 2–3 days similarly to extracellular deposits of hemosiderin, whereas the rarely detectable iron-free pigment hematoidin and spot-like lymphocytic infiltrates in the granulation tissue appear approximately one week or more after wounding. A complete reepithelialization of surgically treated and primarily healing human skin lesions can be expected earliest 5 days after wound infliction and the absence of a complete new epidermal layer indicates a survival time of less than 21 days. Enzyme histochemical methods allow a wound age differentiation especially in the range of a few hours. An increase in nonspecific esterases can be observed earliest approximately 1 hour after wounding followed by other enzymes such as acid phosphatase ( 2 h), ATPase ( 4 h), aminopeptidase ( 4 h) or alkaline phosphatase ( 4 h). Positive results, however, cannot be regularly found. Therefore, the detection of reactive changes is useful for a wound age estimation whereas negative findings, which in general must be interpreted with caution, can provide information only in a limited number of histological parameters.Dedicated to Prof. Dr. W. Eisenmenger on the occasion of his 50th birthday 相似文献
69.
Effect of age and disease duration on parkinsonian motor scores under levodopa therapy 总被引:1,自引:0,他引:1
G. Ransmayr G. Künig M. Neubauer M. Wagner M. Falk 《Journal of neural transmission (Vienna, Austria : 1996)》1995,9(2-3):177-188
Summary One hundred and fifty patients suffering from Parkinson's disease were analysed for the expression of the motor symptoms during optimum response to levodopa therapy (subscale III of the Unified Parkinson's Disease Rating Scale). Patients were grouped according to age (64, 65–74, 75 years). Disease duration and daily levodopa dosage were similar in the three groups. Pooled residual scores for posture and gait impairment (PGI), tremor (T), rigidity (R) and distal motor impairment (DMI; hand and foot movements) increased with age (Kruskal-Wallis ANOVA). The parkinsonian scores were significantly higher than the scores of 150 age-matched normal controls (Mann-Whitney U test). The differences between the patients' scores and the scores of the age-matched controls increased with age. In spite of a significant increase in the daily levodopa dosage with disease duration (linear regression), PGI aggravated age-dependently, and DMI age-independently with symptom duration (Spearman rank correlation). In contrast, T and R did not increase with disease duration. 相似文献
70.
Yorghos Remvikos Henri Magdelenat Bernard Dutrillaux 《Breast cancer research and treatment》1995,34(1):25-33
The influence of age on the occurrence of phenotypic features of prognostic significance was studied in relation to the DNA index values, measured on DNA histograms from a series of 1019 breast cancer patients. Globally, the distributions of all parameters showed variations with age, the most prominent being the decreases in the percentage of estrogen receptor-negative and high proliferative activity cases with increasing age. When analyzed according to the DNA index classes, all parameters were found to some extent linked with the stage of genetic evolution. However, the associations varied with age, defining two extreme groups. The younger patients (less than 40 years) presented a more complete acquisition of the aggressive phenotype and near-triploid tumors from this group were very frequently steroid hormone receptor-negative, high proliferation, and grade III. By contrast, near-triploid tumors in patients above 65 presented relatively frequently as receptor-positive, low proliferative activity, and even grade I. The correlation of the proliferative status with steroid hormone receptor content led to similar conclusions, high proliferation being more strongly correlated with the absence of estrogen and progesterone receptors in younger patients. Interestingly, the association between high proliferation and negative progesterone receptors was much weaker in patients above 55. Our results suggest that the currently established biological prognostic factors, including DNA profile, steroid hormone receptors, and histopathological grade, show patterns of association which vary with age. Of these, only progesterone receptor could be influenced by menopausal status. These findings have to be taken into consideration for future prognostic factor-related treatment decisions, but also for future methodological improvements of multivariate survival analyses. 相似文献