首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   50629篇
  免费   4309篇
  国内免费   1664篇
耳鼻咽喉   755篇
儿科学   762篇
妇产科学   538篇
基础医学   7006篇
口腔科学   726篇
临床医学   6099篇
内科学   7545篇
皮肤病学   803篇
神经病学   2422篇
特种医学   890篇
外国民族医学   13篇
外科学   4374篇
综合类   8209篇
现状与发展   11篇
一般理论   1篇
预防医学   4843篇
眼科学   544篇
药学   3901篇
  45篇
中国医学   3525篇
肿瘤学   3590篇
  2024年   148篇
  2023年   963篇
  2022年   1582篇
  2021年   2260篇
  2020年   2064篇
  2019年   1782篇
  2018年   1888篇
  2017年   1711篇
  2016年   1800篇
  2015年   1664篇
  2014年   3218篇
  2013年   3231篇
  2012年   2911篇
  2011年   3117篇
  2010年   2477篇
  2009年   2279篇
  2008年   2315篇
  2007年   2379篇
  2006年   2046篇
  2005年   1856篇
  2004年   1602篇
  2003年   1506篇
  2002年   1287篇
  2001年   1384篇
  2000年   1180篇
  1999年   1035篇
  1998年   760篇
  1997年   717篇
  1996年   625篇
  1995年   517篇
  1994年   535篇
  1993年   451篇
  1992年   363篇
  1991年   309篇
  1990年   356篇
  1989年   244篇
  1988年   218篇
  1987年   179篇
  1986年   150篇
  1985年   300篇
  1984年   244篇
  1983年   180篇
  1982年   177篇
  1981年   124篇
  1980年   125篇
  1979年   82篇
  1978年   76篇
  1977年   44篇
  1976年   44篇
  1974年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
肺系疾病从脾胃论治的探讨   总被引:5,自引:1,他引:4  
本文论述与肺与脾胃在生理,病理诸方面的密切关系;提出了肺系疾病从脾胃治疗的必要性和重要性;讨论了肺病从脾胃论治之常用7法:即健脾化痰法,芳香醒脾法,健脾利水法,通腑降气法,健脾补肺法,养胃益肺法,补益脾肾法等,对肺系疾病的临床治疗有一定的启发作用和应用价值。  相似文献   
92.
Introduction: Suramin is a synthetic polysulfonated naphthylurea which has been used for the treatment of African trypanosomiasis and onchocerciasis, but since the mid-1980s has received attention as a possible antiretroviral and antineoplastic agent. Objective: This clinical trial of suramin was undertaken as a phase I/II study in patients with hormone-refractory prostate cancer, with the hypothesis that the intensity of therapy with suramin could be increased significantly if measures were undertaken to maintain the plasma concentrations of the drug under 300 μg/ml. Methods: We report the clinical results of this trial, wherein patients were treated at three different targeted plasma suramin concentrations (275, 215 and 175 μg/ml) for varying periods of time (2, 4 or 8 weeks), with delivery of the drug by continuous intravenous infusion. Results: The major toxicity observed in this trial was neurologic, consisting of a motor and sensory peripheral neuropathy that resulted in both paresis and paralysis of the limbs. Nearly all of this severe (CTEP grade III, IV) neurologic toxicity was observed in the patients treated at a plasma suramin concentration of 275 μg/ml for 4 or more weeks. A single patient treated at 215 μg/ml for 8 weeks developed moderate (CTEP grade III) proximal lower extremity weakness, and no patient treated at 175 μg/ml developed this toxicity. The second most common toxicity observed was infection of the central venous catheter. The overall response rate for all of the evaluable patients was 17% (13 of 75 patients). In addition, prostate-specific antigen (PSA)-defined responses were observed in six patients receiving therapy at 175 μg/ml, but these responses were confounded by cessation of therapy with flutamide during suramin treatment. Conclusions: In summary, although plasma suramin concentrations were maintained below 300 μg/ml, neurologic toxicity nonetheless occurred with high frequency in patients treated at 275 μg/ml for 4 or more weeks. Therapy at 215 and 175 μg/ml was in general well tolerated, but central venous catheter-related infection, as well as the inconvenience and expense of continuous infusional therapy, make this method of drug delivery impractical. Only moderate antitumor activity was observed during this trial, but it is possible that both continuation of flutamide and flutamide withdrawal during suramin therapy confounded the assessment of suramin’s activity in hormone-refractory prostate cancer. Received: 9 June 1995/Accepted: 18 March 1996  相似文献   
93.
Hepatocyte regeneration has been widely investigated, with the mitotic index and the incorporation of [3H]thymidine being used as regeneration markers. We focused on the induction of DNA replication enzymes, particularly DNA polymerases (pol) α, δ, and ε. Using rat models, we have shown that the activity of pol α in crude liver extract well represents the regenerating capacity of hepatocytes. Using pol α as an indicator, we analyzed liver regeneration in rat models under various conditions: obstructive jaundice, external or internal biliary drainage, and the obstruction of portal vein branches. It has been revealed that the ligation of the common bile duct alone induces a certain amount of hepatocyte proliferation. It was striking that external biliary drainage suppressed regeneration capacity in cholestatic rat liver after partial hepatectomy. The strong regeneration in nonligated lobes induced by portal branch ligation was similar to the liver regeneration seen after partial hepatectomy with respect to the induction of DNA polymerases. Taken together, the aspects of DNA replication, particularly the induction of DNA polymerases, may contribute to shedding new light on the regeneration of human liver. This work was supported in part by a Grant-in-Aid for General Scientific Research and for Cancer Research from the Ministry of Education, Science and Culture, Japan, and by grants from the Uehara Memorial Foundation  相似文献   
94.
Background: Oncogenes and other molecular tumor markers that predict tumor aggressiveness may allow individualization and optimization of surgical therapy of intermediate-thickness malignant melanoma. We examined the expression of selected markers, including the HLA-DR antigen, the heat shock protein-70 (HSP-70), and the c-myc oncogene in primary melanoma and regional nodes and related these findings to metastatic potential and survival. Methods: Forty patients with primary melanoma (1.5–4.0 mm) were studied, all of whom had prophylactic lymph node dissection and were followed for 18 months to 7 years. The primary tissue and nodes were examined using immunohistochemical techniques for the presence of HLA-DR antigen and HSP-70 protein and the expression of the c-myc oncogene. Results: Of 40 patients, there were 23 with lesions 1 to 2.9 mm thick and 17 with lesions 3 to 4 mm thick. Nodal metastases were present in 25 of the 40 patients who had elective node dissection. HLA-DR antibody stained the primary tumor in 10 patients (25%), but there was no correlation with survival in this group. HLA-DR antibody stained the stroma and cellular infiltrates surrounding the primary tumor in 28 of 40 patients; in this group there was a correlation of HLA-DR staining of the peritumoral stroma with improved survival overall. HLA-DR staining of the peritumoral stroma also influenced survival when patients were stratified by tumor thickness groups 1 to 2.9 mm and 3 to 4 mm and presence of nodal metastases. HSP-70 was demonstrated in the primary tumor in 25% of patients, who were also shown to have significantly improved survival when compared with those whose primary tumor did not stain with HSP-70. C-myc was expressed in the primary tumor in 25%, but showed no correlation with survival. None of these proteins correlated with or predicted the presence of nodal metastases. Conclusion: We conclude that the use of specific molecular-oncogene markers in intermediate-thickness primary melanoma may identify patients at high risk for conventional treatment failure and reduced survival who may profit from more aggressive surgery, adjuvant therapy, or both.Presented at the 48th Annual Cancer Symposium of The Society of Surgical Oncology, Boston, Massachusetts, March 23–26, 1995.  相似文献   
95.
应用放射免疫测定法,对20例胃肠癌患者进行了血清癌胚抗原(CEA)测定,并应用免疫组化法对其中16例癌组织中的CEA进行了检测.检测结果,血清CEA阳性6例,癌组织CEA阳性9例.低分化癌的血清CEA显著高于高分化癌(P<0.05).血清CEA与癌灶部位、癌组织CEA与分化程度及血清CEA均无关(P>0.05).提示血清CEA的含量与癌组织的分化程度有关,血清CEA与癌组织内的CEA无平行关系.作者并对其机制及检测CEA的意义进行讨论.  相似文献   
96.
SA、F/TPSA及PSAD在前列腺癌诊断中的作用   总被引:1,自引:0,他引:1  
目的 :探讨血清前列腺特异抗原 (PSA) ,血清总PSA及游离PSA比值 (F/TPSA)及前列腺特异性抗原密度(PSAD)在前列腺癌诊断中的作用。方法 :对 5 1例前列腺癌患者及 14 5例良性前列腺增生症患者PSA、F/TPSA及PSAD值的差异进行分析、比较。结果 :前列腺癌组血清PSA及PSAD高于良性前列腺增生组 ;而F/TPSA值低于良性前列腺增生组 ,差异均有显著性。结论 :PSA >4ng·ml-1作为筛选前列腺癌的临界值存在一定缺陷 ;当PSA <10ng·ml-1,F/T值有助于鉴别前列腺癌和良性前列腺增生 ;而PSAD对于筛选前列腺活检病例亦有一定价值。  相似文献   
97.
逆转录-聚合酶链反应检测胃癌淋巴结微转移   总被引:1,自引:0,他引:1  
目的 检测胃癌常规病理检查阴性的淋巴结微转移的发生及与其它临床参考指标的关系。方法 利用逆转录-聚合酶链反应(RT-PCR)方法检测68枚胃癌胃周淋巴结癌胚抗原(CEA)mRNA基因表达,同时比较RT-PCR与免疫组化(IHC)方法的检测敏感性。结果 CEAmRNA RT-PCR是一种很敏感的方法,可以检测1/10^6个转移的癌细胞;检测19例胃癌患者取材的68枚胃周淋巴结,IHC阳性率28%(19/68),RT-PCR阳性率57%(39-68),两组之间差异有非常显著性意义(P<0.01);RT-PCR阳性率与胃部临床参考指标密切相关,且随着病期进展而增大。结论 CEA mRNA RT-PCR是比免疫组化更敏感的方法,可以预测胃癌淋巴结微转移,能够有效地避免已有微小转移的患者被漏诊。  相似文献   
98.
目的探讨镍钛记忆合金带膜内支架在治疗食管癌术后胸内吻合口瘘中的应用价值。方法在X线电视透视下对22例食管癌术后胸内吻合口瘘患者进行镍钛记忆合金带膜内支架植入治疗。结果19例一次植入成功,成功率86%,恢复正常饮食;不完全封堵瘘口3例(14%);16例术后出现轻度的胸骨后疼痛不适或胃液反流的症状;1例出现上消化道大出血。22例病人均治愈出院,治愈率100%。结论镍钛记忆合金带膜内支架植入治疗食管癌术后胸内吻合口瘘成功率高,治愈率高,操作简单,安全,见效快,并发症少,有效解除患者痛苦,宜在临床上推广使用。  相似文献   
99.
静脉输液加药后的微粒变化   总被引:7,自引:1,他引:6  
本文对我院急诊病人常用的供静脉给药的22种药物、42组配伍情况,制成静脉加药输液,在超净工作台条件下,用KF—4型微粒计数器,测定了168次微粒数,结果显示输液加药后微粒虽有增加,但均在药典规定范围内。输液中加1种、2种、3种药物后所产生的微粒数分别为x_1=5.52(n_1=16);x_2=8.17(n_2=18)、x_3=10.25(n_3=8),经统计处理,三组间无显著差异(P<0.05)。本文对产生微粒的药物、注射器、操作环境等因素进行了分析。  相似文献   
100.
为探讨临床中使用钙制剂抢救链霉素过敏休克病人有良好效果的原因,由被动血凝试验、被动皮肤过敏试验和ELISA法证实,Ca~( )可以抑制链霉素抗原-抗体的反应。这种抑制作用是通过Ca~( )链霉素抗原结合,封闭链霉素抗原决定簇来加以实现的。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号