全文获取类型
收费全文 | 43126篇 |
免费 | 3014篇 |
国内免费 | 209篇 |
专业分类
耳鼻咽喉 | 404篇 |
儿科学 | 1314篇 |
妇产科学 | 1102篇 |
基础医学 | 5991篇 |
口腔科学 | 1130篇 |
临床医学 | 4736篇 |
内科学 | 8871篇 |
皮肤病学 | 977篇 |
神经病学 | 4491篇 |
特种医学 | 1040篇 |
外科学 | 4183篇 |
综合类 | 354篇 |
一般理论 | 47篇 |
预防医学 | 4948篇 |
眼科学 | 564篇 |
药学 | 2953篇 |
1篇 | |
中国医学 | 141篇 |
肿瘤学 | 3102篇 |
出版年
2024年 | 53篇 |
2023年 | 566篇 |
2022年 | 946篇 |
2021年 | 1709篇 |
2020年 | 1076篇 |
2019年 | 1528篇 |
2018年 | 1777篇 |
2017年 | 1332篇 |
2016年 | 1429篇 |
2015年 | 1634篇 |
2014年 | 1991篇 |
2013年 | 2530篇 |
2012年 | 3768篇 |
2011年 | 3822篇 |
2010年 | 1904篇 |
2009年 | 1602篇 |
2008年 | 2609篇 |
2007年 | 2548篇 |
2006年 | 2392篇 |
2005年 | 2175篇 |
2004年 | 1988篇 |
2003年 | 1721篇 |
2002年 | 1544篇 |
2001年 | 289篇 |
2000年 | 256篇 |
1999年 | 254篇 |
1998年 | 207篇 |
1997年 | 196篇 |
1996年 | 173篇 |
1995年 | 142篇 |
1994年 | 104篇 |
1993年 | 106篇 |
1992年 | 124篇 |
1991年 | 129篇 |
1990年 | 128篇 |
1989年 | 97篇 |
1988年 | 98篇 |
1987年 | 96篇 |
1986年 | 106篇 |
1985年 | 92篇 |
1984年 | 110篇 |
1983年 | 69篇 |
1982年 | 72篇 |
1981年 | 86篇 |
1980年 | 70篇 |
1979年 | 64篇 |
1978年 | 51篇 |
1977年 | 45篇 |
1974年 | 50篇 |
1972年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Sara Mondini Francesca Borgo Biagio Cotticelli Patrizia Bisiacchi 《Journal of the International Neuropsychological Society》2006,12(2):275-284
The evolution of the progressive loss of semantic knowledge of a patient, VZ, with lesions mainly affecting the infero-medial temporal lobes, was followed for two years. At the beginning of the study VZ's performance was mainly characterized by a category-specific deficit for living things and a modality-specific deficit for perceptual attribute knowledge. As time went on, VZ's disorder affected all categories by changing the relationship between category and attribute knowledge. Data show that dissociations may change in the course of progressive cognitive breakdown, depending on both degeneration stage and task demands. VZ's performance is discussed in the light of the most influential theoretical accounts. Methodological suggestions regarding longitudinal studies of degenerative patients are also put forward. 相似文献
62.
63.
Abdulbaqi Al-Toma Marije S Goerres Jos W R Meijer B Mary E von Blomberg Peter J Wahab Jo A M Kerckhaert Chris J J Mulder 《Clinical gastroenterology and hepatology》2006,4(11):1322-7; quiz 1300
BACKGROUND & AIMS: Refractory celiac disease (RCD) may be subdivided into RCD types I and II with phenotypically normal and aberrant intraepithelial T-cell populations, respectively. In RCD II, transition into enteropathy-associated T-cell lymphoma (EATL) is seen frequently. We have evaluated the effect of cladribine (2-CDA), a purine analogue inducing T-cell depletion, on clinical, histopathologic, and immunologic parameters, as well as the toxicity and side effects in a group of RCD II patients. METHODS: Between 2000 and 2005, 17 patients were included (8 men, 9 women). All patients had a clonal rearrangement of the T-cell receptor gamma gene and immunophenotyping showed an aberrant T-cell population lacking surface expression of CD3, CD8, and T-cell receptor alphabeta, in the presence of expression of surface CD103 and intracytoplasmic CD3. Treatment consisted of 2-CDA (0.1 mg/kg/day) intravenously for 5 days, given in 1-3 courses every 6 months depending on the response. RESULTS: All patients tolerated 2-CDA without serious side effects. Six patients (35.8%) showed a clinical improvement (weight gain, improvement of diarrhea, and hypoalbuminemia). In 10 patients (58.8%) a significant histologic improvement and in 6 patients (35.2%) a significant decrease in aberrant T cells was seen. Seven patients (41.1%) developed EATL and died subsequently. One patient died of progressive refractory state with emaciation. CONCLUSIONS: Treatment with 2-CDA in RCD II is feasible, well tolerated, and can induce clinical and histologic improvement as well as a significant decrease of aberrant T cells in a subgroup of patients, albeit it does not prevent EATL development. However, the earlier reported potential risk of precipitating an overt lymphoma should be taken into consideration. 相似文献
64.
Kirsten M Robertson Maria Norg?rd Sara H Windahl Kjell Hultenby Claes Ohlsson G?ran Andersson Jan-Ake Gustafsson 《Journal of bone and mineral research》2006,21(8):1276-1287
The liver X receptor (alpha,beta) is responsible for regulating cholesterol homeostasis in cells. However, our studies using the LXRalpha-/-, LXRbeta-/-, and LXRalpha-/-beta-/- mice show that both LXRalpha and beta are also important for bone turnover, mainly by regulating osteoclast differentiation/activity. Introduction: The liver X receptors (alpha,beta) are primarily responsible for regulating cholesterol homeostasis within cells and the whole body. However, as recent studies show that the role for this receptor is expanding, we studied whether the LXRs could be implicated in bone homeostasis and development. MATERIALS AND METHODS: pQCT was performed on both male and female LXRalpha-/-, LXRbeta-/-, LXRalpha-/-beta-/-, and WT mice at 4 months and 1 year of age. Four-month-old female mice were additionally analyzed with reference to qPCR, immunohistochemistry, histomorphometry, transmission electron microscopy, and serum bone turnover markers. RESULTS: At the mRNA level, LXRbeta was more highly expressed than LXRalpha in both whole long bones and differentiating osteoblast-like MC3T3-E1 and osteoclast-like RAW 264.7 cells. Four-month-old female LXRalpha-/- mice had a significant increase in BMD because of an increase in all cortical parameters. No difference was seen regarding trabecular BMD. Quantitative histomorphometry showed that these mice had significantly more endosteal osteoclasts in the cortical bone; however, these cells appeared less active than normal cells as suggested by a significant reduction in serum levels of cross-linked carboxyterminal telopeptides of type I collagen (CTX) and a reduction in bone TRACP activity. Conversely, the female LXRbeta-/- mice exhibited no change in BMD, presumably because a significant decline in the number of the trabecular osteoclasts was compensated for by an increase in the expression of the osteoclast markers cathepsin K and TRACP. These mice also had a significant decrease in serum CTX, suggesting decreased bone resorption; however, in addition presented with an increase in the expression of osteoblast associated genes, bone formation markers, and serum leptin levels. CONCLUSIONS: Our findings show that both LXRs influence cellular function within the bone, with LXRalpha having an impact on osteoclast activity, primarily in cortical bone, whereas LXRbeta modulates trabecular bone turnover. 相似文献
65.
Gender differences in informal caring 总被引:1,自引:0,他引:1
Men have hitherto largely been invisible in research on informal care. This paper examines gender differences in informal caring, focusing on gender differences according to the relationship between the carer and care-recipient and the location of caring. The paper uses secondary analysis of the 1990–91 General Household Survey, which identified over 2700 adults as informal carers. Four per cent of men and women provide care for someone living in the same household. More women than men, 13% compared with 10%, provide care for someone living in another household. Men carers are less involved in care provision than women, providing fewer hours of care each week, and are less likely to be the main carer. However, gender differences are most marked among married carers, apart from those caring for their spouse, and least among unmarried carers. Married men can often rely on their wives to perform caring roles rather than performing them personally. Women carers are more likely to provide personal care than men carers, but the gender difference is least among those caring for their spouse or for disabled children. Cross-sex personal care is performed within the marital relationship and by parents caring for disabled children, but seldom by adult children caring for their parents or in more distant caring relationships. Evidence of cross-sex taboos in giving personal care is largely restricted to care provided in another household. Since the majority of elderly people in need of care are women, such cultural taboos may reinforce the pressure on mid-life women to care for mothers and mothers-in-law. 相似文献
66.
BACKGROUND: Anaphylaxis must be recognized and treated promptly to avoid significant morbidity and mortality. In this clinical setting, electrocardiographic changes can be multifactorial. OBJECTIVE: To discuss vasospasm as a cause of myocardial ischemia and its possible triggering by anaphylaxis itself or by the administration of epinephrine. METHODS: We describe a patient with multiple previous allergies who received intravenous epinephrine to treat suspected anaphylaxis. She immediately developed crushing chest pain with ST-segment elevations in the inferior leads. Throughout the discussion, we address differential diagnoses, physiologic features, and treatment. RESULTS: Her symptoms and electrocardiographic changes were consistent with vasospasm, which resolved after treatment with sublingual nitroglycerin. However, the reaction was sufficient to cause an elevation in the troponin T level and, therefore, myocardial damage on the cellular level. CONCLUSIONS: Cardiovascular complications, including electrocardiographic changes, may be induced by anaphylactic mediators or by medications used for its treatment. 相似文献
67.
The trajectory, mass fluxes, and deposition of aerosolized particles in a complex tubular system have been predicted. A procedure based on Lagrangian stochastic modeling is proposed to enable the anticipation of such phenomena, taking advantage of experimental results to characterize the air flow. The predictions have been obtained for pharmaceutical aerosols delivered by dry powder inhalers. A critical assessment of the dispersion model has been carried out using data available in the literature. The procedure assumes a low volume fraction of particles in the simulation of turbulent dispersion, but deposition is physically based on the interaction between the particles and both solid and liquid surfaces. The results were confirmed by experimental tests of powder deposition, run according to the European Pharmacopoeia. A parametric study was also carried out with the aim of providing a more complete evaluation of the model’s performance. The comparison between predictions and experimental results has shown that the model properly describes the deposition of aerosolized particles. 相似文献
68.
Virginia L Willour Peter P Zandi Judith A Badner Jo Steele Kuangyi Miao Victor Lopez Dean F MacKinnon Francis M Mondimore Barbara Schweizer Melvin G McInnis Erin B Miller J Raymond Depaulo Elliot S Gershon Francis J McMahon James B Potash 《Neuropsychopharmacology》2007,61(5):725-727
BACKGROUND: We are interested in identifying susceptibility genes that predispose subjects to attempted suicide. METHODS: We conducted a secondary analysis of genome-wide linkage data from 162 bipolar pedigrees that incorporated attempted suicide as a clinical covariate. RESULTS: The strongest covariate-based linkage signal was seen on 2p12 at marker D2S1777. The logarithm of odds (LOD) score at marker D2S1777 rose from 1.56 to 3.82 after inclusion of the suicide covariate, resulting in significant chromosome-wide empirically derived p-values for the overall linkage finding (p = .01) and for the change in LOD score after the inclusion of the covariate (p = .02). CONCLUSIONS: The finding on chromosome 2 replicates results from two previous studies of attempted suicide in pedigrees with alcohol dependence and in pedigrees with recurrent early-onset depression. Combined, these three studies provide compelling evidence for a locus influencing attempted suicide on 2p12. 相似文献
69.
70.