全文获取类型
收费全文 | 141554篇 |
免费 | 11159篇 |
国内免费 | 5596篇 |
专业分类
耳鼻咽喉 | 581篇 |
儿科学 | 2681篇 |
妇产科学 | 1522篇 |
基础医学 | 26934篇 |
口腔科学 | 1706篇 |
临床医学 | 10124篇 |
内科学 | 26894篇 |
皮肤病学 | 2838篇 |
神经病学 | 8107篇 |
特种医学 | 2204篇 |
外国民族医学 | 26篇 |
外科学 | 9320篇 |
综合类 | 18667篇 |
现状与发展 | 26篇 |
预防医学 | 8997篇 |
眼科学 | 1206篇 |
药学 | 19730篇 |
25篇 | |
中国医学 | 5618篇 |
肿瘤学 | 11103篇 |
出版年
2024年 | 262篇 |
2023年 | 1945篇 |
2022年 | 4152篇 |
2021年 | 4776篇 |
2020年 | 4142篇 |
2019年 | 4812篇 |
2018年 | 4483篇 |
2017年 | 4352篇 |
2016年 | 4503篇 |
2015年 | 5192篇 |
2014年 | 8169篇 |
2013年 | 9050篇 |
2012年 | 8207篇 |
2011年 | 9507篇 |
2010年 | 7961篇 |
2009年 | 7801篇 |
2008年 | 7591篇 |
2007年 | 7292篇 |
2006年 | 6645篇 |
2005年 | 5755篇 |
2004年 | 5048篇 |
2003年 | 4437篇 |
2002年 | 3523篇 |
2001年 | 2926篇 |
2000年 | 2572篇 |
1999年 | 2195篇 |
1998年 | 2105篇 |
1997年 | 1754篇 |
1996年 | 1551篇 |
1995年 | 1518篇 |
1994年 | 1284篇 |
1993年 | 1072篇 |
1992年 | 960篇 |
1991年 | 805篇 |
1990年 | 681篇 |
1989年 | 607篇 |
1988年 | 488篇 |
1987年 | 454篇 |
1986年 | 403篇 |
1985年 | 914篇 |
1984年 | 1041篇 |
1983年 | 744篇 |
1982年 | 806篇 |
1981年 | 701篇 |
1980年 | 620篇 |
1979年 | 553篇 |
1978年 | 460篇 |
1977年 | 340篇 |
1976年 | 334篇 |
1975年 | 273篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
71.
Ali Samii Debra D Dahlen Alexander M Spence Nicole C Maronian Eric E Kraus Vanda A Lennon 《Movement disorders》2003,18(12):1556-1558
The paraneoplastic autoantibody, collapsin response-mediator protein (CRMP)-5 immunoglobulin G (IgG), is specific for neuronal cytoplasmic CRMP-5, and is usually associated with small-cell lung carcinoma or thymoma. We report on details of a movement disorder that followed anti-B-cell therapy in a patient with lymphoma, and was accompanied by CRMP-5 IgG. 相似文献
72.
临床上对于乙型肝炎的诊断主要是依据病人的 HBV- M结果进行判断 ,对于单项抗 HBc阳性的临床意义 ,目前有不同的争议。通过在临床工作中搜集整理的有关资料进行总结分析 ,认为单项抗 HBc阳性的意义与其在血清中的滴度有关。 相似文献
73.
S G Beck 《Synapse (New York, N.Y.)》1992,10(4):334-340
In the presence of spiperone to block the 5-HT1A-mediated inhibition of pyramidal cell activity, 5-hydroxytryptamine (serotonin, 5-HT) produces a rapid transient increase in amplitude of the extracellularly recorded population spike from area CA1 of the hippocampus. Intracellular recording techniques in area CA1 of rat hippocampal slices were used to identify the ionic mechanism and to characterize the 5-HT receptor mediating this excitatory response to 5-HT. Most of the experiments were conducted in the presence of spiperone to block the 5HT1A hyperpolarization. Since spiperone also has high affinity for 5-HT2 receptors, any response mediated by 5-HT2 receptors would also be blocked. Bath perfusion of the slice with 5-HT increased the rectification of pyramidal cells in the subthreshold region, increased the resistance, and increased the amplitude of subthreshold excitatory postsynaptic potentials (EPSPs) to initiate spike firing. The 5-HT2,1C-selective agonist DOI mimicked this effect of 5-HT, and the 5-HT2,1C antagonist ketanserin (1 microM) blocked the effect of DOI. There was no change in the amplitude of the slow afterhyperpolarization (sAHP) or the amplitude of evoked inhibitory postsynaptic potentials (IPSPs). The increase in rectification and EPSP amplitude by 5-HT occurred even in the presence of the 5-HT4-selective antagonist BRL 24924 to prevent the decrease in amplitude of the sAHP by 5-HT. We conclude that 5-HT produces a fast excitatory response by increasing subthreshold conductance in CA1 hippocampal pyramidal cells. The identity of the receptor mediating this response was not conclusively identified, but resembled the 5-HT1C receptor. 相似文献
74.
75.
76.
Helene Z. Hill Maimu Ohanian George J. Hill Richard Winne 《Journal of surgical oncology》1987,34(4):264-267
Intraoperative radiation therapy (IORT) research is limited by the lack of small-animal models. We have implanted B16 melanoma into mouse kidneys, which we subsequently operated upon and irradiated with beta rays from a 90Sr ophthalmic applicator. The IORT has effectively prolonged survival and produced some cures. The strategy should be applicable to other murine tumors and to other internal implantation sites. 相似文献
77.
O. JOHNSTON J. CRAWFORD H. SHORT T. RAYMOND SMYTH J. MOLLER 《Journal of paediatrics and child health》1987,23(3):157-161
A simple standardized screening test (South Australian Motor Co-ordination Screening Test, SAM Test) was developed to screen for poor co-ordination in 5 year olds; This SAM Test, which can be used by teachers, nurses and doctors, has explicit pass/fail criteria and has classified correctly 90% of children. The McCarthy Motor Scales, which are time consuming and limited to use by psychologists, were used to categorize 60 poorly co-ordinated and 60 normal children. The 120 children thus selected were tested on 19 items covering gross and fine motor skills. Statistical analysis to determine which items best discriminated between the two groups found the following five gross motor items to be most effective: one leg balancing, hopping, heel-toe walking on line, jumping Over ribbon and dropping ball and catching. 相似文献
78.
Summary We have identified cells which secrete human chorionic gonadotropin (HCG) of cultures if first trimester placental villi. As a first step, we identified epithelial cells using a new monoclonal antibody. We then added HCG antibodies to the cultured cells. We found that syncytiotrophoblast (and not cytotrophoblast), Hofbauer cells and some mesenchymal cells stained with HCG antibodies. 相似文献
79.
Corinna S. Bowser Jean Kaye Rauno O. Joks Cascy-Arnoux Charlot H. Jack Moallem 《Pediatric allergy and immunology》2007,18(4):298-303
Elevated serum immunoglobulin E (IgE) and increased prevalence of atopy is reported in patients infected with human immunodeficiency virus (HIV). The elevated serum IgE may be attributed to polyclonal stimulation of B cells or IgE production against allergens, viruses, fungi and bacteria. This study investigates the prevalence of atopy in perinatally HIV-infected children, and the relationships between serum IgE (and other serum immunoglobulins) with atopy, CD4+ cell count and HIV-disease stage. Serum immunoglobulin levels, epicutaneous skin test for common aeroallergens, clinical Centers for Disease Control and Prevention (CDC) classification, CD4+ cell counts and allergy history were extracted from the charts of perinatally HIV-infected children on highly active antiretroviral therapy. The prevalence of atopy (52%) and the pattern of aeroallergen sensitivity were comparable with the US pediatric population. Serum IgE levels did not correlate with clinical disease stage. However, in non-atopic patients, serum IgE levels increased with disease progression (p = 0.02). There was an inverse relationship between the prevalence of elevated serum IgE levels and atopy with progression of disease (p = 0.019). Serum IgE did not correlate with atopy, CD4+ cell count, or duration of HIV infection or levels of serum immunoglobulins. This is the first study to show no increased prevalence of atopy in perinatally HIV-infected children compared with the general population. In advanced stages of HIV, elevated serum IgE may be specific for antigens other than those known as allergens. 相似文献
80.
BACKGROUND: Reduced Th1 and elevated Th2 cytokine responses are considered to be a principal mechanism in the generation of the inflammation leading to the manifestations of atopic disease in the skin of atopic dermatitis and in the airways of asthma. If reduced Th1 and elevated Th2 responses are principal determinants of the manifestation of atopic disease it might be expected that subjects with established disease would exhibit differences in their cytokine profiles as compared with atopic patients without clinical disease. OBJECTIVE: To determine whether asymptomatic atopic children exhibit a cytokine imbalance similar to that seen in patients with established atopic disease or if they behave like non-atopic controls. Cytokine responses in a group of children with elevated IgE but no clinical manifestations of disease, atopic children with established disease and non-atopic controls were compared. METHODS: We examined allergen-induced (house dust mite, HDM, rye grass pollen and RYE) cytokine responses in parallel with polyclonal (staphylococcal enterotoxin B, SEB) cytokine responses in a group of children with elevated serum IgE levels without current or past evidence of atopic disease (median age 6.6 years) and compared these with a non-atopic control group (median age 6.5 years) and a group of children with atopic disease (median age 6.7 years). RESULTS: Symptomatic atopic children had reduced SEB-induced IFN-gamma and increased SEB-induced IL-4 and IL-5 as compared with non-atopic controls. In contrast, SEB-induced IFN-gamma, IL-4 and IL-5 production in asymptomatic atopics was not significantly different from the non-atopic control subjects. Allergen-induced Th1 (IFN-gamma) and Th2 (IL-5 and IL-13) cytokine production was increased in both symptomatic atopics and asymptomatic atopics when compared with non-atopic controls. CONCLUSION: The defect in polyclonally induced IFN-gamma production was associated with the clinical manifestation of atopic disease but not the atopic stateper se. This suggests that the global reduction in IFN-gamma is the key determinant of the development of overt atopic disease. In contrast, elevated allergen-induced Th2 cytokine responses in children related to the atopic state per se irrespective of the presence of clinical atopic disease. 相似文献