全文获取类型
收费全文 | 5910篇 |
免费 | 420篇 |
国内免费 | 87篇 |
专业分类
耳鼻咽喉 | 38篇 |
儿科学 | 114篇 |
妇产科学 | 212篇 |
基础医学 | 750篇 |
口腔科学 | 156篇 |
临床医学 | 558篇 |
内科学 | 1141篇 |
皮肤病学 | 94篇 |
神经病学 | 379篇 |
特种医学 | 270篇 |
外科学 | 822篇 |
综合类 | 380篇 |
一般理论 | 2篇 |
预防医学 | 367篇 |
眼科学 | 108篇 |
药学 | 453篇 |
4篇 | |
中国医学 | 122篇 |
肿瘤学 | 447篇 |
出版年
2023年 | 60篇 |
2022年 | 127篇 |
2021年 | 203篇 |
2020年 | 114篇 |
2019年 | 143篇 |
2018年 | 214篇 |
2017年 | 132篇 |
2016年 | 137篇 |
2015年 | 212篇 |
2014年 | 252篇 |
2013年 | 310篇 |
2012年 | 471篇 |
2011年 | 468篇 |
2010年 | 277篇 |
2009年 | 255篇 |
2008年 | 336篇 |
2007年 | 355篇 |
2006年 | 329篇 |
2005年 | 271篇 |
2004年 | 241篇 |
2003年 | 240篇 |
2002年 | 208篇 |
2001年 | 124篇 |
2000年 | 147篇 |
1999年 | 99篇 |
1998年 | 34篇 |
1997年 | 29篇 |
1996年 | 22篇 |
1995年 | 32篇 |
1994年 | 22篇 |
1993年 | 18篇 |
1992年 | 63篇 |
1991年 | 45篇 |
1990年 | 32篇 |
1989年 | 35篇 |
1988年 | 36篇 |
1987年 | 28篇 |
1986年 | 28篇 |
1985年 | 36篇 |
1984年 | 31篇 |
1983年 | 25篇 |
1982年 | 22篇 |
1981年 | 26篇 |
1980年 | 13篇 |
1979年 | 18篇 |
1978年 | 13篇 |
1977年 | 16篇 |
1976年 | 14篇 |
1975年 | 11篇 |
1974年 | 10篇 |
排序方式: 共有6417条查询结果,搜索用时 15 毫秒
31.
El-Harazi SM Feldman RM Villanueva G Carter-Dawson L Mietz H Chuang AZ 《Journal of glaucoma》1999,8(6):374-379
PURPOSE: Mitomycin C (MMC) is commonly administered during filtering surgery to enhance the success of the procedure. Unfortunately, the increased success rate is associated with complications, including late bleb leaks, endophthalmitis, and ciliary epithelial toxicity. The purpose of this study was to investigate a safe and effective dose regimen for MMC to reduce incidence of those complications. METHODS: Trabeculectomy was performed in 36 rabbits. MMC was applied only during surgery, only one day after surgery, or once daily after surgery for 3 days at lower concentrations. Balanced salt solution (BSS) was administered during surgery to one group as a placebo. The time to bleb failure was determined and the eyes were evaluated histopathologically. Success and toxicity were compared for the different treatment groups. RESULTS: The mean time until trabeculectomy failure was 2.83 days for the placebo group, 6.33 days with administration of MMC 0.5 mg/mL during surgery, 7.83 days with administration of MMC 0.5 mg/mL once after surgery, and 11, 9, and 4.83 days with administration of MMC 0.1 mg/mL, 0.05 mg/mL, or 0.025 mg/mL, respectively, once a day for 3 consecutive days. On electron microscopic examination of the ciliary epithelium, toxic effects were greatest with MMC concentrations of 0.5 mg/mL and were less with lower concentrations. CONCLUSION: The effect of MMC on trabeculectomy survival was dependent on both the concentration and the method of administration. Lower concentrations with multiple postoperative administrations were as effective as but caused less ciliary body toxicity than intraoperative administration of higher concentrations. 相似文献
32.
Effects of nonsteroidal anti-inflammatory drugs and prostaglandins on osteoblastic functions. 总被引:3,自引:0,他引:3
It has been reported that nonsteroidal anti-inflammatory drugs (NSAIDs) suppress bone repair and bone remodeling but only mildly inhibit bone mineralization at the earlier stage of the repair process. We proposed that the proliferation and/or the earlier stage of differentiation of osteoblasts may be affected by NSAIDs. This study was designed to investigate whether NSAIDs affect the proliferation and/or differentiation of osteoblasts and whether these effects are prostaglandin (PG) mediated. The effects of PGE1 and PGE2, indomethacin, and ketorolac on thymidine incorporation, cell count, intracellular alkaline phosphatase (ALP) activity, and Type I collagen content in osteoblast-enriched cultures derived from fetal calvaria were evaluated. The results showed that both PGs and NSAIDs inhibited DNA synthesis and cell mitosis in a time- and concentration-dependent manner. However, intracellular ALP activity and Type I collagen content were stimulated at an earlier stage of differentiation in osteoblasts. These results suggested that (i) the inhibitory effect of ketorolac on osteoblastic proliferation contributes to its suppressive effects on bone repair and remodeling in vivo; (ii) PGEs and NSAIDs may be involved in matrix maturation and biologic bone mineralization in the earlier stage of osteoblast differentiation; and (iii) the effects of ketorolac and indomethacin on cell proliferation and differentiation may not be through the inhibition of the synthesis of PGE1 or PGE2. 相似文献
33.
细辛脑片剂的生物利用度 总被引:17,自引:0,他引:17
吴闯 《中国医院药学杂志》2003,23(10):597-598
目的 :比较两种不同生产工艺的细辛脑片剂生物利用度。方法 :18名健康志愿者单剂量随机交叉口服不同生产工艺的片剂 1和片剂 2 16 0mg ,及静脉注射细辛脑针剂 16mg后 ,用反相高效液相色谱法测定细辛脑血清浓度 ,对AUC0~∞ ,Cmax和Tmax3个参数进行等效性检验。结果 :片剂 1和片剂 2的绝对生物利用度分别为 (5 .4± 1.6 ) %和 (9.7± 2 .5 ) % ,片剂 2对片剂 1的相对生物利用度为 (181.9± 15 .2 ) %。结论 :经生产工艺改造后的片剂 2生物利用度比原生产工艺片剂 1提高81.9% ,但是 ,细辛脑片剂的绝对生物利用度仍很低。 相似文献
34.
目的在简介磷脂的基础上 ,概括了磷脂类似物和磷脂聚合物的合成方法及其在医药领域中的应用。方法在参阅国内外相关文献的基础上 ,进行分析、整理和归纳。结果磷脂聚合物的合成方法已经发展的比较成熟 ,但是在医药方面的应用主要限于磷脂聚合物型脂质体、聚乙二醇(PEG)修饰型脂质体和磷脂修饰型聚合物。结论具有两亲性和生物相容性的磷脂及其聚合物在医药领域具有广泛的发展前景 相似文献
35.
针刺手法的运用是针灸临床治疗的一个关键环节。针刺手法的基本功锻炼是提高针刺手法操作技术的重要途径。本文详细介绍了针刺手法基本功锻炼的步骤和方法。 相似文献
36.
PURPOSE: We describe the establishment and preliminary characterization of a cell line designated SCRC-1, which was derived from a primary renal small cell carcinoma. MATERIALS AND METHODS: Continuous cultures of a primary stage IVa renal small cell carcinoma and a xenograft in nude mice derived therefrom were characterized by immunohistology, electron microscopy, immunofluorescence/flow cytometry, cytogenetic analysis, and an in vitro drug resistance assay. RESULTS: SCRC-1 cells were reactive with antibodies to NSE, chromogranin-A, bombesin, Bcl-2, CD44s, CD44v6, CD44v7 to 8, vimentin and S100 protein (predominantly beta-subunit), and were unreactive with antibodies to EMA, CD54, EGFR(R1), URO-5, URO-7, URO-8 and URO-10. A similar immunoprofile was also found in both the primary tumor and the xenograft. Cytogenetic analysis revealed the following common clonal aberrations in all 50 metaphases analyzed: 45, XX, t (X;10;18) (p11;p11;q11), -der(18)t(X;10;18), indicating the clonal nature of this neoplasm. SCRC-1 cells showed low drug resistance to cyclophosphamide, doxorubicin, gemcitabine and fluorouracil, intermediate resistance to carmustine and mitomycin-C, and extreme resistance to cisplatin. CONCLUSION: We have documented the initial characterization of SCRC-1, which may be the first cell line reported to be derived from a primary small cell carcinoma of the kidney. This cell line can be used for further studies uncovering the biology and histogenesis of this rare cancer and delineating differences among small cell carcinomas of the kidney and other histological types. 相似文献
37.
Risk factors for wound infection after cholecystectomy. 总被引:3,自引:0,他引:3
Shih-Chang Chuang King-Teh Lee Wen-Tsan Chang Shen-Nien Wang Kung-Kai Kuo Jong-Shyong Chen Pai-Ching Sheen 《台湾医志》2004,103(8):607-612
BACKGROUND AND PURPOSE: Surgical site infection (SSI) after cholecystectomy is a common problem. The aim of this study was to identify the possible risk factors for the development of SSI. METHODS: 545 consecutive patients who received open (125) or laparoscopic (420) cholecystectomy due to gallbladder disease during the years 1998 to 2000 were included in the study. Potential risk factors including clinical features, biochemical data, and operative types were analyzed by univariate and multivariate analysis. RESULTS: The overall incidence of SSI was 4.4% (24/545). The wound complication rate was significantly lower in the laparoscopic group than in the open group (1.4% vs 14.4%, respectively). Factors associated with SSI found by univariate analysis (p < 0.05) included age, gender, acute cholecystitis, white blood cell count, serum albumin, blood glucose and bilirubin level, type of surgery, operative time and positive bile culture. Stepwise logistic regression analysis showed that abnormal blood glucose [odds ratio (OR), 4.7; 95% confidence interval (CI), 1.6 to 13.5], positive bile culture (OR, 3.5; 95% CI, 1.2 to 10.4), and open cholecystectomy (OR, 4.3; 95% CI, 1.3 to 13.6) were the most significant predictors of SSI. CONCLUSION: Poor control of diabetes mellitus before surgery, positive bile culture and open cholecystectomy significantly increased the rate of SSI. These findings indicate that better control of diabetes mellitus, and appropriate selection of surgical procedure and antibiotic regimen in the management of high-risk patients may reduce the incidence of postoperative SSI. 相似文献
38.
拉米夫定对不同中医证型的慢性乙型肝炎疗效辨析 总被引:2,自引:0,他引:2
丛川 《浙江中医药大学学报》2006,30(3):251-251,253
拉米夫定是一种有效的抗乙肝病毒药物,它对病毒的逆转录酶有明显的抑制作用,可抑制乙肝病毒的复制,降低血液和肝脏中的病毒数量,改善肝脏生化功能和组织学病变,从而提高患者生存质量。为进一步提高拉米夫定治疗慢性乙型肝炎的疗效,本文收集统计了近4年的80例相关病例,从中医辨证的角度,分析应用拉米夫定治疗不同证型的慢性乙型肝炎的疗效。现报告如下。1临床资料1·1一般资料收集本院肝炎科门诊慢性乙型肝炎患者80名,其中男性47名,女性33名,年龄17~64岁,平均35岁。诊断标准依据2000年全国传染病与寄生虫病学会和肝病学会修订的病毒性肝炎诊… 相似文献
39.
Brain undergoes neurodegeneration when excess free radicals overwhelm antioxidative defense systems during senescence, head trauma and/or neurotoxic insults. A site-specific accumulation of ferrous citrate-iron complexes in the substantia nigra dopaminergic neurons could lead to exaggerated dopamine turnover, dopamine auto-oxidation, free radical generation, and oxidant stress. Eventually, this iron-catalyzed dopamine auto-oxidation results in the accumulation of neuromelanin, a progressive loss of nigral neurons, and the development of Parkinson's disease when brain dopamine depletion is greater than 80%. Emerging evidence indicates that free radicals such as hydroxyl radicals ((.-)OH) and nitric oxide ((.-)NO) may play opposite role in cell and animal models of parkinsonism. (.-)OH is a cytotoxic oxidant whereas oNO is an atypical neuroprotective antioxidant. (.-)NO and S-nitrosoglutathione (GSNO) protect nigral neurons against oxidative stress caused by 1-methyl-4-phenylpyridinium (MPP(+)), dopamine, ferrous citrate, hemoglobin, sodium nitroprusside and peroxynitrite. MPP(+), the toxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), increases the nigral uptake of iron complexes and dopamine overflow leading to the generation of (.-)OH, protein oxidation, lipid peroxidation, and associated retrograde degeneration. In addition to GSNO, MPP(+)-induced oxidative neurotoxicity can be prevented by antioxidants including selegiline, 7-nitroindazole, 17beta-estradiol, melatonin, alpha-phenyl-tert-butylnitrone and U78517F. Similar to selegiline, 7-nitroindazole is a MAO-B inhibitor, which blocks the bio-activation of MPTP and oxidative stress. Freshly prepared but not light exposed, (.-)NO-exhausted GSNO is about 100 times more potent than the classic antioxidant glutathione. Via S-nitrosylation, GSNO also inhibits proteolysis and cytotoxicity caused by caspases and HIV-1 protease. Furthermore, in addition to protection against serum deprivation stress, the induction of neuronal NOS1 in human cells increases tolerance to MPP(+)-induced neuro-toxicity since newly synthesized (.-)NO prevents apoptosis possibly through up-regulation of bcl-2 and down regulation of p66(shc). In conclusion, reactive oxygen species are unavoidable by-products of iron-catalyzed dopamine auto-oxidation, which can initiate lipid peroxidation, protein oxidation, DNA damage, and nigral loss, all of which can be prevented by endogenous and exogenous (.-)NO. Natural and man-made antioxidants can be employed as part of preventative or neuroprotective treatments in Parkinson's disease and perhaps dementia complexes as well. For achieving neuroprotection and neuro-rescue in early clinical parkinsonian stages, a cocktail therapy of multiple neuroprotective agents may be more effective than the current treatment with extremely high doses of a single antioxidative agent. 相似文献
40.
目的:比较不同提取方法制备的石菖蒲挥发油中的挥发性化学成分。方法:采用传统的水蒸气蒸馏提取挥发油,超临界流体萃取挥发油和顶空进样直接采集挥发性成分3种方法,对石菖蒲中的挥发性成分进行GC-MS分析。结果:顶空进样技术鉴定出44种挥发性化学成分;水蒸气蒸馏法可鉴定出23种挥发性化学成分;超临界流体萃取可鉴定出25种化合物,经GC-MS分析,水蒸气蒸馏法与粉末顶空进样有14种化合物相同,超临界流体萃取与粉末顶空进样有8种化合物相同,相对含量均有一定的差异。结论:顶空进样技术分析石菖蒲中挥发性成分更简单、快速、无溶剂残留并节省药材。 相似文献