全文获取类型
收费全文 | 46077篇 |
免费 | 4350篇 |
国内免费 | 3317篇 |
专业分类
耳鼻咽喉 | 359篇 |
儿科学 | 516篇 |
妇产科学 | 326篇 |
基础医学 | 4212篇 |
口腔科学 | 905篇 |
临床医学 | 5951篇 |
内科学 | 5209篇 |
皮肤病学 | 339篇 |
神经病学 | 1689篇 |
特种医学 | 1780篇 |
外国民族医学 | 18篇 |
外科学 | 4541篇 |
综合类 | 10257篇 |
现状与发展 | 9篇 |
一般理论 | 1篇 |
预防医学 | 4200篇 |
眼科学 | 863篇 |
药学 | 5381篇 |
57篇 | |
中国医学 | 3805篇 |
肿瘤学 | 3326篇 |
出版年
2024年 | 255篇 |
2023年 | 742篇 |
2022年 | 1846篇 |
2021年 | 2120篇 |
2020年 | 1781篇 |
2019年 | 1242篇 |
2018年 | 1291篇 |
2017年 | 1347篇 |
2016年 | 1221篇 |
2015年 | 1955篇 |
2014年 | 2433篇 |
2013年 | 2657篇 |
2012年 | 3739篇 |
2011年 | 4033篇 |
2010年 | 3271篇 |
2009年 | 2661篇 |
2008年 | 2983篇 |
2007年 | 2930篇 |
2006年 | 2659篇 |
2005年 | 2329篇 |
2004年 | 1532篇 |
2003年 | 1512篇 |
2002年 | 1132篇 |
2001年 | 971篇 |
2000年 | 904篇 |
1999年 | 827篇 |
1998年 | 471篇 |
1997年 | 485篇 |
1996年 | 346篇 |
1995年 | 310篇 |
1994年 | 327篇 |
1993年 | 176篇 |
1992年 | 217篇 |
1991年 | 187篇 |
1990年 | 155篇 |
1989年 | 153篇 |
1988年 | 130篇 |
1987年 | 106篇 |
1986年 | 79篇 |
1985年 | 85篇 |
1984年 | 28篇 |
1983年 | 21篇 |
1982年 | 15篇 |
1981年 | 11篇 |
1980年 | 6篇 |
1979年 | 20篇 |
1959年 | 4篇 |
1958年 | 12篇 |
1957年 | 5篇 |
1955年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
HSP27在大肠癌及癌旁组织中的表达及其意义 总被引:2,自引:0,他引:2
目的 :探讨热休克蛋白 2 7(HSP2 7)在大肠癌及癌旁组织中的表达及意义。方法 :应用免疫组化S P法检测 72例大肠癌组织和癌旁组织HSP2 7表达情况。结果 :HSP2 7在癌组织与癌旁组织的表达率分别是 4 0 2 8%和 18 75 % ,二者差异有统计学意义 (P <0 0 1)。HSP2 7在高、中、低分化腺癌组织中表达分别是 6 3 6 4 %、31 5 8%和 10 0 0 % ,统计学分析三者之间存在显著性差异 (P <0 0 1)。在大肠癌组织、癌旁组织中HSP2 7表达率与年龄、性别、淋巴结转移、临床分期无相关性 ,但在 >5 0岁组中有 9例呈过表达 (9/ 2 3) ,而≤ 5 0岁组中则无过表达者 ;在伴有淋巴结转移癌组织中HSP2 7表达率为4 3 4 8%。无淋巴结转移者为 38 78% ,统计学分析虽然无显著性差异 (P >0 0 5 ) ,但无淋巴结转移组中HSP2 7有 9例过表达 ,有淋巴结转移组则无 1例过表达。结论 :HSP2 7表达在大肠癌发生过程中发挥重要作用 ,并可能具有抑制肿瘤细胞的恶性转型及防止其侵袭发展作用。 相似文献
82.
Population-based case-control study of CYP11A gene polymorphism and breast cancer risk. 总被引:9,自引:0,他引:9
Wei Zheng Yu-Tang Gao Xiao-Ou Shu Wanqing Wen Qiuyin Cai Qi Dai Jeffrey R Smith 《Cancer epidemiology, biomarkers & prevention》2004,13(5):709-714
The CYP11A gene encodes the cholesterol side-chain cleavage enzyme (P450scc) that catalyzes the first and rate-limiting step for the biosynthesis of sex hormones. A pentanucleotide repeat [(TAAAA)n] polymorphism in the 5' of the CYP11A gene has been reported to be related to the risk of polycystic ovary syndrome, an inherited endocrine disorder characterized by hyperandrogenemia. We investigated the association of this polymorphism with breast cancer risk in a population-based case-control study conducted among Chinese women in Shanghai. Genotype assays were completed for 1015 incident breast cancer cases and 1082 community controls. Three common alleles with 4, 6, or 8 TAAAA repeats were identified in the study population. The frequency of the 8 repeat allele was more common in cases (12.6%) than controls (8.5%) (odds ratio = 1.6, 95% confidence interval = 1.3-1.9; P < 0.0001). Compared to subjects who did not carry this allele, adjusted odds ratios were 1.5 (95% confidence interval = 1.2-1.9) and 2.9 (1.3-6.7) (P for trend, <0.001), respectively, for those who carried one and two copies of this allele. This positive association was observed in both pre- and postmenopausal women and all strata defined by major breast cancer risk factors, including years of menstruation, body mass index, and waist-to-hip ratio. The results from this study indicate that the TAAAA repeat polymorphism near the promoter region of the CYP11A gene may be an important susceptibility factor for breast cancer risk. 相似文献
83.
OBJECTIVE: The goal of this study was to investigate the clinical and paraclinical features, treatment, and outcomes of patients with multiple sclerosis (MS) and coexisting spinal cord compression secondary to either cervical spondylosis or cervical disc disease. Patients with MS commonly experience neurological disabilities that present as myelopathy associated with bladder dysfunction. For some patients with MS, however, this neurological deterioration may result from coexisting spinal cord compression attributable to either spondylosis or a herniated disc. Overlapping symptoms of the two conditions do not allow clear clinical determination of the underlying cause of worsening. METHODS: Patients with MS who underwent cervical decompression surgery were selected. Medical records were retrospectively reviewed, to collect data on their pre- and postoperative clinical courses. RESULTS: Nine women and five men with definite MS were selected for cervical decompression surgery to treat neurological deterioration considered to be at least partially attributable to spinal cord compression. The most common symptoms were progressive myelopathy (n = 13), neck pain (n = 11), and cervical radiculopathy (n = 10). Bladder dysfunction was notably absent among these patients with MS with moderate disabilities. Surgical intervention was frequently delayed because the neurological deterioration was initially thought to be attributable to MS. The majority of patients experienced either improvement or stabilization of their preoperative symptoms in the immediate postoperative period; three subjects (21%) maintained this improvement after a mean follow-up period of 3.8 years. No MS relapses, permanent neurological worsening, or serious complications resulting from surgery or general anesthesia were noted. CONCLUSION: Carefully selected patients with MS and cervical spinal cord compression secondary to either spondylosis or disc disease may benefit from surgical decompression, with minimal associated morbidity. Clinical features (especially neck pain and cervical radiculopathy) and magnetic resonance imaging may assist clinicians in differentiating between the two conditions and may guide appropriate treatment without undue delay. 相似文献
84.
HPLC测定消食止泻散中橙皮苷的含量 总被引:5,自引:0,他引:5
赵彩云 《现代中药研究与实践》2003,17(1):37-38
目的 建立消食止泻散中橙皮苷的含量测定方法。方法 超声提取 ,HPL C测定消食止泻散中橙皮苷的含量。 C1 8柱 ,乙腈 -水 -磷酸 (180∶ 82 0∶ 0 .1)为流动相 ,检测波长为 2 83nm,柱温 :2 8℃。结果 橙皮苷含量测定的线性范围为 0 .197μg~ 1.182μg,r=0 .9999,n=6 ,平均加样回收率为 99.8 ,RSD为 1.3%。结论 本方法准确 ,简便 ,快速 ,可用于消食止泻散的质量控制。 相似文献
85.
CT-based delineation of lymph node levels and related CTVs in the node-negative neck: DAHANCA, EORTC, GORTEC, NCIC,RTOG consensus guidelines. 总被引:25,自引:0,他引:25
Vincent Grégoire Peter Levendag Kian K Ang Jacques Bernier Marijel Braaksma Volker Budach Cliff Chao Emmanuel Coche Jay S Cooper Guy Cosnard Avraham Eisbruch Samy El-Sayed Bahman Emami Cai Grau Marc Hamoir Nancy Lee Philippe Maingon Karin Muller Hervé Reychler 《Radiotherapy and oncology》2003,69(3):227-236
BACKGROUND AND PURPOSE: The appropriate application of 3-D CRT and IMRT for HNSCC requires a standardization of the procedures for the delineation of the target volumes. Over the past few years, two proposals--the so-called Brussels guidelines from Grégoire et al., and the so-called Rotterdam guidelines from Nowak et al.--emerged from the literature for the delineation of the neck node levels. Detailed examination of these proposals however revealed some important discrepancies. MATERIALS AND METHODS: Within this framework, the Brussels and Rotterdam groups decided to review their guidelines and derive a common set of recommendations for delineation of neck node levels. This proposal was then discussed with representatives of major cooperative groups in Europe (DAHANCA, EORTC, GORTEC) and in North America (NCIC, RTOG), which, after some additional refinements, have endorsed them. The objective of the present article is to present the consensus guidelines for the delineation of the node levels in the node-negative neck. RESULTS AND CONCLUSIONS: First a short discussion of the discrepancies between the previous Brussels and the Rotterdam guidelines is presented. The general philosophy of the consensus guidelines and the methodology used to resolve the various discrepancies are then described. The consensus proposal is then presented and representative CTVs that are consistent with these guidelines are illustrated on CT sections. Last, the limitations of the consensus guidelines are discussed and some concerns about the direct applications of these guidelines to the node-positive neck and the post-operative neck are described. 相似文献
86.
Kobayashi N Ito M Nakamura J Cai J Cao C Hammel JM Fox IJ 《Transplantation proceedings》2000,32(7):2287-2288
87.
88.
肾上腺素诱导兔血小板聚集的实践与理论探讨 总被引:1,自引:0,他引:1
目的创建以Adr诱导兔血小板聚集的方法,并对受体分子特性作初步探讨。方法以高K+缓冲液等取代兔PRP中血浆,以Adr诱导聚集,以Apyr证实结果。结果兔血小板悬浮于高K+缓冲液时Adr能单独诱导真正的聚集。结论由此推测血小板膜上α2肾上腺素受体分子可能为由两种亚单位组成:促聚亚单位和辅助亚单位。人辅助亚单位当Adr浓度高达聚集阈值以上时可被激活,与促聚亚单位结合为活性的二聚体,与Adr进一步结合发生聚集作用。兔辅助亚单位则还需要高K+方能被激活 相似文献
89.
氯硝安定与安定溶液直肠给药用于惊厥急救的对照研究 总被引:21,自引:1,他引:21
目的以安定为对照,探讨氯硝安定溶液直肠给药对惊厥急救的实用价值。方法在28例儿童中对比观察直肠注入氯硝安定与安定溶液的吸收速度和对脑电活动的影响,并比较两药对大鼠实验性惊厥的疗效。结果氯硝安定与安定溶液均能从直肠迅速吸收,皆于用药5分钟后达有效血浓度,分别于3~8分钟及2~8分钟对脑电活动产生显著影响,明显抑制癫痫样波发放,使美解眠诱发的惊厥致死率从对照组的70%降为0。结论氯硝安定与安定溶液直肠给药,均能作为小儿惊厥抢救的有效措施。 相似文献
90.
喉腔及喉咽部平滑肌肉瘤3例报告 总被引:3,自引:0,他引:3
为了解发生于喉腔及喉咽部的平滑肌肉瘤的临床特点,报告1例喉咽部平滑肌肉瘤和2例喉腔平滑肌肉瘤患者早期症状都不明显,且无特异性,临床表现与该部常见鳞癌极为相似,术前明确诊断有一定困难。 相似文献