全文获取类型
收费全文 | 19444篇 |
免费 | 1669篇 |
国内免费 | 625篇 |
专业分类
耳鼻咽喉 | 70篇 |
儿科学 | 675篇 |
妇产科学 | 312篇 |
基础医学 | 2776篇 |
口腔科学 | 284篇 |
临床医学 | 1360篇 |
内科学 | 2992篇 |
皮肤病学 | 592篇 |
神经病学 | 1413篇 |
特种医学 | 281篇 |
外国民族医学 | 1篇 |
外科学 | 1588篇 |
综合类 | 2094篇 |
现状与发展 | 2篇 |
预防医学 | 2924篇 |
眼科学 | 229篇 |
药学 | 2449篇 |
3篇 | |
中国医学 | 630篇 |
肿瘤学 | 1063篇 |
出版年
2023年 | 216篇 |
2022年 | 692篇 |
2021年 | 899篇 |
2020年 | 637篇 |
2019年 | 708篇 |
2018年 | 708篇 |
2017年 | 696篇 |
2016年 | 686篇 |
2015年 | 706篇 |
2014年 | 1108篇 |
2013年 | 1555篇 |
2012年 | 932篇 |
2011年 | 1152篇 |
2010年 | 882篇 |
2009年 | 851篇 |
2008年 | 854篇 |
2007年 | 909篇 |
2006年 | 892篇 |
2005年 | 723篇 |
2004年 | 694篇 |
2003年 | 628篇 |
2002年 | 519篇 |
2001年 | 456篇 |
2000年 | 354篇 |
1999年 | 280篇 |
1998年 | 291篇 |
1997年 | 241篇 |
1996年 | 239篇 |
1995年 | 201篇 |
1994年 | 168篇 |
1993年 | 137篇 |
1992年 | 121篇 |
1991年 | 120篇 |
1990年 | 128篇 |
1989年 | 92篇 |
1988年 | 101篇 |
1987年 | 90篇 |
1986年 | 68篇 |
1985年 | 135篇 |
1984年 | 125篇 |
1983年 | 91篇 |
1982年 | 123篇 |
1981年 | 93篇 |
1980年 | 75篇 |
1979年 | 64篇 |
1978年 | 48篇 |
1977年 | 42篇 |
1976年 | 40篇 |
1975年 | 46篇 |
1973年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Tobias Forschner Stefan Buchholtz Eggert Stockfleth 《Journal der Deutschen Dermatologischen Gesellschaft》2007,5(6):467-475
Vitiligo is a skin disease with a worldwide prevalence ranging from 0.5% to 4%. Conservative therapies include photochemotherapy, phototherapy with UVB radiation (broadband UVB 290–320 nm, narrow band UVB 311 nm), systemic steroids and pseudocatalase. Modern therapeutic options include treatment with topical immunomodulators (tacrolimus, pimecrolimus), analogues of vitamin D3, excimer laser and surgery/transplantation. Our analysis compares these therapies for vitiligo and the evidence levels supporting their effectiveness. Conclusions: The face and neck respond best to all therapeutic approaches, while the acral areas are least responsive. For generalized vitiligo, phototherapy with UVB radiation is most effective with the fewest side effects; PUVA is the second best choice.Topical corticosteroids are the preferred drugs for localized vitiligo. They may be replaced by topical immunomodulators which display comparable effectiveness and fewer side effects.The effectiveness of vitamin D analogues is controversial with limited data. Surgical therapy can be very successful, but requires an experienced surgeon and is very demanding of time and facilities, thus limiting its widespread use. L-phenylalanine therapy appears effective on the face but enjoys neither widespread use nor extensive data support. No single therapy for vitiligo can be regarded as the most effective as the success of each treatment modality depends on the type and location of vitiligo. 相似文献
82.
E. Lanke A. M. Johansson A. Hillarp S. Lethagen B. Zller B. Dahlbck C. Halldn 《Journal of thrombosis and haemostasis》2004,2(11):1918-1923
Inherited deficiency of protein S constitutes an important risk factor of venous thrombosis. Many reports have demonstrated that causative mutations in the protein S gene are found only in approximately 50% of the cases with protein S deficiency. It is uncertain whether the protein S gene is causative in all cases of protein S deficiency or if other genes are involved in cases where no mutation is identified. The aim of the current study was to determine whether haplotypes of the protein S gene cosegregate with the disease phenotype in cases where no mutations have been found. Eight protein S-deficient families comprising 115 individuals where previous DNA sequencing had failed to detect any causative mutations were analyzed using four microsatellite markers in the protein S gene region. Co-segregation between microsatellite haplotypes and protein S deficiency was found in seven of the investigated families, one family being uninformative. This suggests that the causative genetic defects are located in or close to the protein S gene in a majority of such cases where no mutations have been found. 相似文献
83.
复合维生素E,C,B组合物面膜治疗寻常痤疮117例的疗效和安全性(英文) 总被引:1,自引:0,他引:1
目的:了解维生素E,C,B组合物面膜治疗寻常痤疮的疗效及安全性。方法:117例13a以上、痤疮严重程度分级在2级以上且主要表现于脸部的病人,予维生素E,C,B组合物面膜治疗,每日1次,共8wk。观察治疗前后痤疮数量及性质,包括粉刺、丘疹、脓疱及囊肿之数目,并评估整体疗效。结果:治疗后,粉刺、丘疹、脓疱及囊肿数目下降了13±s13,10±12,5±7及3±3,均P<0.01。7例(6.0%)病人症状完全改善,44例(37.6%)中度改善,56例(47.9%)轻度改善,10例(8.6%)无改善。59例(50.4%)病人无红肿、搔痒、灼热及脱皮等现象发生。结论:维生素E,C,B组合物面膜治疗痤疮有效,超过半数的受试者无不良反应发生,可作为传统治疗寻常痤疮药物的替代。 相似文献
84.
内皮细胞生长因子诱导大鼠血管内皮细胞增殖过程中FKBP12的表达 总被引:1,自引:1,他引:0
目的探讨内皮细胞生长因子(Endothelial cell growth factor,ECGF)诱导的血管内皮细胞(Vascular endothelial cell,VEC)增殖过程中FK506结合蛋白12(FK506 binding protein 12,FKBP12)表达的变化,为VEC的鉴定提供新的方法。方法培养大鼠VEC并传代。倒置显微镜下观察其在ECGF作用下的增殖情况,检测Ⅷ因子相关抗原、FKBP12和不同时期FKBP12 mRNA水平的表达。结果VEC表达FKBP12;VEC传代后第4天FKBP12 mRNA表达水平达到最高,6—8d下降。结论FKBP12既可作为VEC的标志物,又可反映VEC的增殖情况。 相似文献
85.
白细胞介素-12基因修饰对树突状细胞表面分子表达及细胞因子分泌的影响 总被引:1,自引:0,他引:1
目的 观察白细胞介素(IL)-12基因修饰对树突状细胞(DC)表面分子及细胞因子分泌的影响.方法 采用重组逆转录病毒介导IL-12基因修饰人外周血单个核细胞(PBMC)来源的Dc;ELISA法检测各组DCs和各组T细胞上清中IL-12、IL-10、IFN-γ因子的分泌水平;流式细胞仪(FACS)分析各组DC表面CD83、CD86的表达;MTT法检测DC刺激同源T淋巴细胞增殖的能力;统计学分析比较各组间的差异.结果 IL-12基因修饰使得DC高表达CD83和CD86分子,分泌高水平IL-12及IFN-γ,但对IL-10因子的分泌无明显影响,刺激同源T淋巴细胞增殖明显,诱导激活的T细胞上清中IFN-γ水平显著增高、IL-10分泌水平显著降低.结论 经IL-12基因修饰后的DC表型成熟,分泌IL-12及IFN-γ的能力增强,对IL-10因子的分泌无影响,能抑制T细胞分泌IL-10因子,优化抗原提呈的微环境. 相似文献
86.
Summary The effect of vitamin A deficiency was studied in chickens infected with 500 Ascaridia galli eggs and controls. Diet 1 (deficient, 500 IU vitamin A or 172 μg retinol acetate per kg diet), Diet 2 (deficient, 1000 IU
vitamin A or 344 μg retinol acetate per kg diet) and Diet 3 (sufficient, 1500 IU vitamin A or 516 μg retinol acetate per kg
diet) were assigned to 46 chickens each. Clinical signs, weight gains, livers’ weights, vitamin A levels, worm burdens and
parasite eggs’ excretions were recorded.
Infected chickens had lower weight gains than the controls fed alike. Chickens given Diet 1 stored lesser vitamin A in liver
than those fed Diet 3. Although worm counts in the 3 groups did not differ significantly, chickens fed Diet 1 excreted more
A. galli eggs than those fed the 2 other diets. Female worms harboured by chickens fed Diet 1 had higher fecundity at week 5 pi than
those of chickens fed Diet 2. Results indicated that Vitamin A is important for poultry in the moderation of the infection
with A. galli. 相似文献
87.
Biological properties of interleukin-12 and its therapeutic use in persistent hepatitis B virus and hepatitis C virus infection 总被引:2,自引:0,他引:2
Summary. Interleukin (IL)-12 is a pleiotropic cytokine produced by antigen-presenting cells in response to diverse stimuli. IL-12 is a key molecule in the regulation of host's immune responses. In particular, IL-12 influences the balance between the T-helper cells type 1 (TH1 ) and type 2 (TH2 ); it modulates macrophage responses through the control of interferon-gamma synthesis by TH1 cells; and, suppresses IgE class antibody production (has a suppressive effect on allergic reactions) and promotes a shift in the IgG subclasses. IL-12 enhances resistance to several infectious diseases, is a powerful antitumor agent in vivo , and acts as a vaccine adjuvant. The biological properties of IL-12 point to the potential therapeutic use in persistent hepatitis B virus and hepatitis C virus infection. 相似文献
88.
Marlon Normandin Joel Gagn Julie Bernard Robert lie Dom Miceli Michel Baudry Guy Massicotte 《Brain research》1996,730(1-2):40-46
Low-frequency stimulation is associated with long-term depression (LTD) of synaptic efficacy in various brain structures. Like long-term potentiation (LTP), homosynaptic LTD in area CA1 of the hippocampus appears to require NMDA receptor activation, changes in postsynaptic calcium concentration and phospholipase A2 (PLA2) activation. Arachidonic acid (AA) is released after the activation of calcium-dependent phospholipases and free AA is rapidly metabolized to a family of bioactive products (the eicosanoids) which are thought to be both intracellular and extracellular messengers. In the present study, we investigated the involvement of the cyclooxygenase and lipoxygenase pathways of AA metabolism in the formation of homosynaptic LTD in the rat hippocampus. Stimulation at 1 Hz for 15 min was used to produce homosynaptic depression in area CA1 of hippocampal slices. LTD induction was partially blocked by bromophenacyl bromide (50–100 μM), a selective PLA2 inhibitor, and by the a nonselective lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA; 100 μM). In contrast, the specific cyclooxygenase blocker indomethacin (100 μM) did not significantly reduce hippocampal LTD. Since NDGA interferes with LTD formation, we examined whether specific inhibitors of 5- and 12-lipoxygenases were capable of blocking LTD expression. The 12-lipoxygenase inhibitor baicalein at a concentration of 50 μM reduced LTP formation when given in the bath, an effect that was less pronounced with the 5-lipoxygenase inhibitor AA-861. These data suggest that the activation of endogenous PLA2 and the formation of 12-lipoxygenase metabolites of AA may be important factors controlling the expression of hippocampal LTD. 相似文献
89.
Chromaffin cells of the adrenal medulla and their tumor counterparts, the pheochromocytoma (PC12) cells, are well-established
model systems in neurobiology. The development of sympathoadrenal progenitor cells to chromaffin cells can be studied with
regard to developmental signals which trigger the differentiation. With regard to potential treatments of neurological disorders
like Parkinson’s disease chromaffin cell grafting can be used as one therapeutical approach. The beneficial effect of chromaffin
cell grafts is possibly not only related to the release of dopamine but may also be linked to the release of growth factors.
One of the growth factors that is synthesized by chromaffin and PC12 cells is basic fibroblast growth factor (FGF-2). The
experimental data available so far, are in agreement with different functional roles of FGF-2. This article summarizes the
putative physiological functions of FGF-2 in the adrenal medulla. Three differential functional roles of FGF-2 are discussed:
(1) as a differentiation factor for sympathoadrenal progenitor cells; (2) as a target-derived neurotrophic factor for preganglionic
sympathetic neurons which innervate adrenal medullary cells; (3) as an auto-/paracrine factor in the adrenal medulla.
Accepted: 21 August 1996 相似文献
90.