全文获取类型
收费全文 | 83791篇 |
免费 | 9136篇 |
国内免费 | 6187篇 |
专业分类
耳鼻咽喉 | 778篇 |
儿科学 | 840篇 |
妇产科学 | 729篇 |
基础医学 | 8764篇 |
口腔科学 | 1767篇 |
临床医学 | 11056篇 |
内科学 | 10358篇 |
皮肤病学 | 846篇 |
神经病学 | 3759篇 |
特种医学 | 3258篇 |
外国民族医学 | 41篇 |
外科学 | 8419篇 |
综合类 | 17486篇 |
现状与发展 | 26篇 |
一般理论 | 7篇 |
预防医学 | 6921篇 |
眼科学 | 2114篇 |
药学 | 9467篇 |
133篇 | |
中国医学 | 6251篇 |
肿瘤学 | 6094篇 |
出版年
2024年 | 368篇 |
2023年 | 1447篇 |
2022年 | 3810篇 |
2021年 | 4796篇 |
2020年 | 3939篇 |
2019年 | 2881篇 |
2018年 | 2906篇 |
2017年 | 3084篇 |
2016年 | 2769篇 |
2015年 | 4288篇 |
2014年 | 5303篇 |
2013年 | 5111篇 |
2012年 | 7516篇 |
2011年 | 8096篇 |
2010年 | 5769篇 |
2009年 | 4811篇 |
2008年 | 5402篇 |
2007年 | 4868篇 |
2006年 | 4434篇 |
2005年 | 3829篇 |
2004年 | 2459篇 |
2003年 | 2102篇 |
2002年 | 1608篇 |
2001年 | 1303篇 |
2000年 | 1263篇 |
1999年 | 1094篇 |
1998年 | 614篇 |
1997年 | 597篇 |
1996年 | 476篇 |
1995年 | 436篇 |
1994年 | 345篇 |
1993年 | 231篇 |
1992年 | 225篇 |
1991年 | 169篇 |
1990年 | 176篇 |
1989年 | 137篇 |
1988年 | 117篇 |
1987年 | 109篇 |
1986年 | 87篇 |
1985年 | 47篇 |
1984年 | 16篇 |
1983年 | 16篇 |
1982年 | 12篇 |
1981年 | 11篇 |
1980年 | 6篇 |
1979年 | 10篇 |
1978年 | 4篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1926年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Xiaoguang Chen Yi Li Lei Wang Mark Katakowski Lijie Zhang Jieli Chen Yongxian Xu Subhash C. Gautam Michael Chopp 《Neuropathology》2002,22(4):275-279
Intravenous administration of human bone marrow stromal cells (hMSCs) after middle cerebral artery occlusion (MCAo) in rats provides functional benefit. We tested the hypothesis that these functional benefits are derived in part from hMSC production of growth and trophic factors. Quantitative sandwich enzyme‐linked immunosorbent assay (ELISA) of hMSCs cultured with normal and MCAo brain extracts were performed. hMSCs cultured in supernatant derived from ischemic brain extracts increased production of brain‐derived neurotrophic factor (BDNF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). These neurotrophins and angiogenic growth factors increased in a post‐ischemia time‐dependent manner. The hMSC capacity to increase expression of growth and trophic factors may be the key to the benefit provided by transplanted hMSCs in the ischemic brain. 相似文献
42.
为了探讨局部麻醉和模拟定位机引导在集束巨能刀治疗肺癌的射频治疗的适应证、治疗效果以及并发症的预防和处理,采用0.5%普鲁卡因局部浸润麻醉,模拟定位机引导下经皮穿刺集束巨能刀治疗肺癌46例。CT显示条索状瘢痕残余ll例,空洞形成或直径缩小32例,无变化1例,增大2例。治疗中患者均有不同程度的胸腔内热感及短时间内可以忍受的疼痛感。并发症包括气胸7例、皮下气肿5例、发热24例、咯血13例和慢性支气管炎急性发作4例。初步研究结果提示,集束巨能刀射频治疗周围型肺癌疗效满意,尤其适用于直径〈3cm的肿瘤。局部麻醉配合全身止痛药物应用可以很好地解决治疗中的疼痛问题,与全麻相比还具有省时省力、费用低的优势;对于周围型肺癌,模拟定位机引导经皮穿刺定位与CT引导相比,同样准确、安全,但操作更为方便。 相似文献
43.
目的:观察按阴阳辨证分类组方联合拉米夫定治疗慢性乙型肝炎(CHB)的临床疗效。方法:90例CHB患者,随机分治疗组及对照组各45例,对照组除一般保肝、对症治疗外,加用拉米夫定抗病毒治疗,疗程6个月。治疗组在对照组用药基础上,按阴阳辨证法则分类组方治疗。口苦、便干、尿黄、苔黄腻、舌尖红、脉弦数或滑数均为有热属阳,用肝炎I号方治疗(茵陈,栀子,滑石,公英,二花,连翘,贯众,虎杖,柴胡,赤芍,郁金,当归,川芎,枳壳,甘草),无阳热征象即按阴湿类用肝炎II号方治疗(党参,白术,茯芩,黄芪,仙灵脾,山药,熟地,山萸肉,柴胡,升麻,干姜,甘草,虎杖),疗程与对照组相同,前3个月每天1剂,后3个月隔日1剂,水煎2次取汁400ml,分早晚服。疗程结束时,观察两组患者肝功能、乙肝病毒标志物及HBVDNA的变化。结果:治疗组与对照组患者血清谷丙转氨酶(ALT)正常率分别为91%与75.5%,两组相比,差异有显著性(P<0.05);HBeAg、HBVDNA阴转率分别为29%、14%及31%、21%,两组相比差异有显著性(P<0.01或P<0.05);未见明显不良反应。结论:按阴阳辨证分类组方联合拉米夫定治疗CHB有改善肝功能和抑制乙肝病毒复制的功效,且辨证指标明确,易于在临床推广。 相似文献
44.
RNA干扰基因敲除MAGE-1在恶性胶质瘤U87细胞中的初步研究 总被引:4,自引:4,他引:0
目的:通过构建抑制MAGE-1的短片段双链核糖核酸(siRNA)表达载体,鉴定其在人恶性胶质瘤细胞系U87细胞中对MAGE.1基因表达的干涉作用。方法:化学合成2对编码短发夹RNA序列的靶向MAGE—1基因寡核苷酸链,克隆至经BglⅡ、HindⅢ双酶切的pSUPER载体上,重组构建核糖核酸干扰(RNAi)质粒载体。利用RT-PCR、流式细胞术和荧光显微镜,检测经稳定转染后胶质瘤U87细胞中MAGE-1的表达,以了解siRNA的干涉效果。结果:重组构建的pSUPER—MAGE—1载体经双酶切、电泳及插入基因片段序列分析,表明寡核苷酸链成功地插入至预计位点,且序列与预期完全一致。稳定转染后G418筛选出的U87多克隆细胞MAGE-1的表达经RT—PCR、流式细胞术和荧光显微镜检测,2对siRNA均有较明显的干扰作用。结论:载体的成功构建并能对U87细胞中的MAGE—1分子进行RNAi,为进一步研究MAGE—1在肿瘤中的作用,分析基因功能,展开肿瘤基因治疗奠定了基础。 相似文献
45.
本文试图阐明不同情期大鼠血浆神经降压素含量的变化。血浆神经降压素以无水乙醇提取后采用放射免疫分析法测定。间情期、动情前期和动情期大鼠血浆内神经降压素样免疫活性物质的含量依次分别为92.1±7.7ng/L,118.0±9.4ng/L 和144.3±10.2ng/L。动情期大鼠血浆神经降压素样免疲活性物质的含量较间情期大鼠有极显著差异(P<0.01)。 相似文献
46.
H N Qian J Feng H Cui B S Gao S L Qin T Y Fu P Wei Z Y Fu S M Gao Z Y Yang 《中华医学杂志(英文版)》1991,104(2):109-113
Monoclonal antibody 131I-COC183B2, developed in our laboratory and proved to fit for human treatment was injected intraperitoneally or subcutaneously in 13 patients. In 8 cases with i.p. injection the disease corresponded with the image, i.e. 3 primary ovarian epithelial cancers showed positive images, 1 ovarian Krukenberg tumor was negative and the other 4 negative images included 1 uterine myoma and 3 ovarian teratomas. In the subcutaneous injection group, 4 cases had ovarian carcinoma, surgery and chemotherapy. Two negative images corresponded with the clinical status-in good health, another negative case had metastatic left supraclavicular lymph node due to ovarian mucinous adenocarcinoma. The last negative image in this group was a case of benign ovarian teratoma which was proved after surgery. The 1 positive case was waiting to be proved by a scheduled third operation. The computer scintigram calculation of T/NT was 5.35 to 13.7. The results suggest that this monoclonal antibody can be used for radioimmunoimaging for the localization of ovarian carcinoma, which is not only helpful for clinical staging and differential diagnosis but is also a good follow-up method.
相似文献
47.
BACKGROUND: As a non-invasive technique which can provide comprehensive biological information, 1H-magnetic resonance spectroscopy (1H-MRS) may provide valuable reference data for irreversible recovery or reversible changes in ischemic tissue after stroke.
OBJECTIVE: To monitor and evaluate the effect of the urokinase thrombolytic therapy after experimental acute cerebral ischemia by 1H-MRS technology and investigate its adaptability.
DESIGN: Randomly controlled animal study.
SETTINGS: Shenzhen Hospital of Peking University and National Key Laboratory of Pattern and Atom & Molecular Physics, Wuhan Physics and Mathematics Institute, Chinese Academy of Science.
MATERIALS: Eleven healthy adult Sprague-Dawley (SD) rats, weighing 260–300 g and of both genders, were supplied by Experimental Animal Center of Tongji Medical Collage, Huazhong University of Science and Technology [SCXK (e) 2004-007]. 4.7T superconducting nuclear magnetic resonance meter was provided by Brucker Company.
METHODS: The experiment was carried out in Shenzhen Hospital of Peking University and National Key Laboratory of Pattern and Atom & Molecular Physics, Wuhan Physics and Mathematics Institute, Chinese Academy of Science from August 2003 to December 2005. ① The rats were randomly divided into 30-minute self-thrombo-embolism group (n =6) and 60-minute self-thrombo-embolism group (n =5). Six rats in 30-minute self-thrombo-embolism group were occluded with clot embolus for 30 minutes and 5 rats in 60-minute self-thrombo-embolism group were occluded for 60 minutes. 10 000 U/kg urokinase was dissolved in 2 mL saline and the operation lasted for 5 minutes. ② 1H-MRS was performed before thrombolysis and at 3 hours and 24 hours after successful embolization. The metabolic changes of N-acetyl-L-aspartic acid (NAA)/phosphocreatine (PCr) + creatine (Cr), choline phosphate (Cho)/PCr+Cr and lactic acid (Lac)/PCr+Cr in the region of interests were analyzed. ③ The T2W image was conducted 24 hours after the thrombolytic therapy with TR=500 ms and TE=25 ms. ④ The subjects were sacrificed immediately after 1H-MRS and the brain tissues were cut into pieces and stained with HE method; in addition, pathological changes were observed under optic microscope.
MAIN OUTCOME MEASURES: ① Metabolic changes of NAA/PCr+Cr, Cho/PCr+Cr and Lac/PCr+Cr in the region of interests; ② T2W image at 24 hours after the thrombolysis; ③ pathological observation of brain tissue.
RESULTS: Eleven rats were all involved in the final analysis. ① Metabolic changes in the region of interests : In 30-minute self-thrombo-embolism group, the Lac peak emerged immediately after the embolism, but the ischemic zone decreased 3 hours after the thrombolytic therapy (0.252±0.01, 0.603±0.01, P < 0.01). Lac/(PCr+Cr) ratio was 0.290±0.01 at 24 hours after thrombolysis, which was higher than that at 3 hours after thrombolysis (P < 0.01). The NAA/ (PCr+Cr) ratio decreased significantly at 3 hours after the thrombolysis as compared with that before thrombolysis (0.922±0.16, 1.196±0.01, P < 0.05). In 60-minute self-thrombo-embolism group, the Lac/(PCr+Cr) ratio was higher at 3 hours after thrombolysis than that before thrombolysis (0.846±0.12, 0.601±0.11, P < 0.05) and the NAA/(PCr+Cr) decreased at 3 hours after the embolism. Fluctuation of NAA/ (PCr+Cr) ranged from 0.68 to 0.75 before thrombolysis and from 0.71 to 0.75 at 3 hours after thrombolysis. ② T2W image: T2W image showed that 2 subjects in 30-minute self-thrombo-embolism group whose Lac/NAA was higher than 0.7 suffered from intracranial hemorrhage. This meant that the subjects with Lac/NAA > 0.7 were more likely to suffer from intracranial hemorrhage. ③ Histological and morphological examinations: Optic microscope demonstrated that interspace surrounding nerve cells was widened at ischemic center; neurons were swelling; nucleus was stained lightly; pyknosis and mesenchymal edema were mainly observed in lateral cortex of brow and vertex and in lateral part of corpus striatum.
CONCLUSION: ①Compound parameters in ischemic area before thrombolysis should be regarded as an important predicting marker for thrombolytic therapy, effect evaluation and termination. ② 1H-MRS combining with other imaging technique is a detecting way for screening cases who are suitable for thrombolytic therapy. 相似文献
48.
547例垂体腺瘤延迟诊断原因及影像诊断分析 总被引:2,自引:0,他引:2
目的:提高垂体腺瘤特别是微腺瘤早期影像诊断率。方法:通过对所搜集病史资料完整,经医学影像学确诊和手术病理证实的547例垂体腺瘤(内有251例微腺瘤)延迟诊断原因的分析,找到影响垂体腺瘤早期诊断的因素。结果:296例垂体大腺瘤蝶鞍X线平片、CT、MR常规检查即可诊断。CT骨窗蝶鞍片有助于垂体微腺瘤的诊断,251例微腺瘤经高分辨力CT薄层冠状强化扫描和高场强MR薄层强化扫描得以明确诊断。结论:熟悉垂体腺瘤的首发症状,及时行CT、MR常规扫描可明确大腺瘤的诊断,CT骨窗片可发现垂体微腺瘤的佐证。高场强MR薄层强化扫描是目前诊断垂体微腺瘤的最佳方法,高分辨力CT冠状薄层强化扫描次之,结合神经内分泌学检查是提高垂体腺瘤影像学早期诊断率的主要措施。 相似文献
49.
Lidong Zhang James E Littlejohn Yu Cui Xiaobo Cao Chander Peddaboina W Roy Smythe 《Molecular cancer》2010,9(1):110
Background
Bortezomib, a proteasome-specific inhibitor, has emerged as a promising cancer therapeutic agent. However, development of resistance to bortezomib may pose a challenge to effective anticancer therapy. Therefore, characterization of cellular mechanisms involved in bortezomib resistance and development of effective strategies to overcome this resistance represent important steps in the advancement of bortezomib-mediated cancer therapy. 相似文献50.
Varatharaj Mounasamy Christopher Dawson Quanjun Cui William M. Mihalko Khaled J. Saleh Thomas Brown 《European journal of orthopaedic surgery & traumatology : orthopedie traumatologie》2007,17(3):313-315
Direct vascular injury after primary total knee arthroplasty is rare. This case report illustrates a 65-year-old female who was diagnosed with a pseudoaneurysm of the popliteal artery when she was investigated for increased leg swelling and pain 1 week after total knee arthroplasty. She had a percutaneous endovascular repair with a stent after thrombectomy. 相似文献