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   35111篇
  免费   3339篇
  国内免费   2099篇
耳鼻咽喉   302篇
儿科学   570篇
妇产科学   150篇
基础医学   1955篇
口腔科学   483篇
临床医学   4107篇
内科学   2725篇
皮肤病学   358篇
神经病学   680篇
特种医学   1090篇
外科学   3646篇
综合类   10239篇
现状与发展   9篇
预防医学   4355篇
眼科学   310篇
药学   4249篇
  36篇
中国医学   3652篇
肿瘤学   1633篇
  2024年   169篇
  2023年   383篇
  2022年   1009篇
  2021年   1339篇
  2020年   1193篇
  2019年   627篇
  2018年   666篇
  2017年   886篇
  2016年   706篇
  2015年   1251篇
  2014年   1771篇
  2013年   2250篇
  2012年   3389篇
  2011年   3428篇
  2010年   3220篇
  2009年   2781篇
  2008年   2939篇
  2007年   2803篇
  2006年   2517篇
  2005年   2013篇
  2004年   1378篇
  2003年   1106篇
  2002年   817篇
  2001年   784篇
  2000年   603篇
  1999年   231篇
  1998年   30篇
  1997年   52篇
  1996年   35篇
  1995年   20篇
  1994年   49篇
  1993年   22篇
  1992年   15篇
  1991年   15篇
  1990年   8篇
  1989年   12篇
  1988年   2篇
  1987年   14篇
  1986年   9篇
  1985年   5篇
  1982年   1篇
  1931年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Candida krusei发酵生产甘油过程中,菌体生长由玉米浆限制,菌体对玉米浆的得率为1.63g/g,培养其中玉米浆浓度相同时,增加渗透压或通过流加补料限制生长阶段的菌体生长,可使甘油生产阶段的比耗糖速率减慢,比耗糖速率保持在不很高的水平,可以因消耗的葡萄糖用于生长,维持,甘油和副产物形成所占比例的变化而提高甘油得率。  相似文献   
22.
目的:观察督脉敷贴利斯的明透皮贴剂治疗轻中度阿尔茨海默病(AD)的临床疗效。方法:采用随机数字表法将90例轻中度AD患者分为督脉敷贴组、常规敷贴组、多奈哌齐组各30例。多奈哌齐组给予多奈哌齐片治疗,常规敷贴组给予常规敷贴利斯的明透皮贴剂治疗,督脉敷贴组给予督脉敷贴利斯的明透皮贴剂治疗。比较3组治疗前后老年性痴呆认知评定量表(ADAS-Cog)、简易智力状态检查量表(MMSE)、老年性痴呆临床总体印象量表(ADAS-CGIC)、老年性痴呆日常生活活动量表(ADAS-ADL)评分,并记录3组不良反应发生情况。结果:治疗12周、24周后,3组ADAS-CGIC、ADAS-Cog评分均较治疗前降低(P<0.05),MMSE、ADAS-ADL评分升高(P<0.05),且督脉敷贴组治疗12周、24周后ADAS-CGIC、ADAS-Cog评分低于常规敷贴组、多奈哌齐组(P<0.05),MMSE、ADAS-ADL评分高于低于常规敷贴组、多奈哌齐组(P<0.05)。常规敷贴组治疗24周后ADAS-CGIC、ADAS-Cog评分低于多奈哌齐组(P<0.05),MMSE、ADA...  相似文献   
23.
王彩云  蔡慧君  况琦 《新中医》2023,55(13):208-211
慢性非特异性腰痛是康复科门诊常见疾病之一,由于其具体病理机制还未完全阐明,目前临床治疗多以对症治疗为主。张海峰主任结合自身临证经验,根据非特异性腰痛的疾病特点,认为其多是以人体体用关系失和所致。人体以一元之气为“体”,脏腑经络的外在功能为“用”。脾肾亏虚,运化失职,气化失常,气血不充,一元之气虚衰,不荣则痛,发为腰痛;气虚血瘀,阻滞经络,又或再受邪气侵犯,寒湿阻滞,不通则痛,而成本虚标实之证。张主任据此提出通补元气、化瘀止痛的治疗法则,并且结合中西医及康复物理治疗等方法,疗效甚佳。  相似文献   
24.
从人膀胱上皮癌细胞株T24的亚克隆株T24-8的无血清培养上清液经55%硫酸铵沉淀,再对无离子水透析,得到了有诱导LAK 细胞活性的粗提品。有此作用的因子称为LAK 细胞诱导因子(LAK-IF)。它的分子量为67KD,等电点为pH3.1~3.5。抗人IL-6单抗不能阻断LAK-IF 的作用。LAK-IF 粗提品经Mono-Q 柱快速蛋白液相层析见3个峰。第2峰蛋白质有LAK-IF 活性。  相似文献   
25.
Objective To analyse the relationship between age and treatment with captopril after acute myocardial infarction (AMI). Methods In a randomized trial, 822 patients with a first AMI received conventional medic al treatment, including intravenous thrombolytic therapy and oral aspirin or metoprolol, and then were randomly allocated to captopril [dosage fr om the first 6.25 mg to 25 mg/t.i.d, 209 younger patients (≤64 years), 269 elderly patients (65-75 years)] or conventional treatment only (131 younger p atients, 213 elderly). Survival in the four groups was calculated with the Kapl an-Meier method. Multivariate analysis was performed to understand the degree that multi-variables (including age) affect survival in patients taking captopr il in the hospital or during long term follow-up. Results The survival of patients who took captopril correlated significantly with age ( P&lt;0.001). The survival of the elderly patients on captopril treatment did increase (P&lt;0.0001), but not of the younger ones (P&gt;0.05) during hosp italization. During follow-up, the survival of patients who took captopril cor related insignificantly with age (P&gt;0.05), but both the elderly and the you n ger patients have good survival rates (all P&lt;0.01) and lower cardiac events (all P&lt;0.01) when they took captopril.Conclusions Captopril exerts a weak effect on the younger patients but a beneficial effect o n the elderly patients during hospitalization after AMI. However, there is no d ifference between the younger and the elderly in the prognosis, both having good survival and lower cardiac events when they take captopril long term during fol low-up.  相似文献   
26.
Background Previous studies have shown conflicting results on the relation between clinicopathologic features and prognosis of patients with colorectal mucinous, signet-ring cell, or non-mucinous adenocarcinoma; only few such studies have been performed in China. This retrospective study analyzed data from our department to investigate clinicopathologic characteristics, prognosis and possible correlations of three histologic types -- colorectal mucinous,signet-ring cell, and non-mucinous adenocarcinoma, to clarity the bases for observed differences which may lead to development of targeted therapies Methods Of 2079 patients diagnosed with colorectal cancer between 1994 and 2007, 144 had mucinous, 25 had signet-ring cell, and 1837 had non-mucinous adenocarcinoma. Their clinicopathologic parameters and survival were analyzed using established statistical methodologies.Results Mucinous and signet-ring cell adenocarcinomas were common in younger patients (P <0.001). Location, size and disease stage differed significantly among the three types. Signet-ring cell tumors were more commonly found in the rectum than mucinous and non-mucinous adenocarcinoma (P <0.001). Mucinous and signet-ring cell tumors presented in a later stage in life more often than non-mucinous adenocarcinoma, with lymph node involvement, serosal infiltration, peritoneal dissemination, and adjacent organ invasion (P <0.01). The rate of radical resection, hepatic metastasis and local recurrence did not differ among types (P >0.05). Compared with patients with non-mucinous adenocarcinoma, patients with mucinous and signet-ring cell tumors who underwent potentially curative resections or stage Ⅱ/Ⅲ disease had poorer long-term overall survival. Survival did not differ by type for patients with either stage Ⅰor Ⅳ disease (P >0.05). Conclusions Mucinous and signet-ring cell adenocarcinoma have unique carcinogenesis and similar biologic behavior.Our study confirms that both histologic types, especially signet-ring cell tumors, are independent, negative prognostic factors for patients with colorectal cancer. Type does not appear to have a significant effect on survival when disease is either stage Ⅰ or Ⅳ at presentation.  相似文献   
27.
Background Although the indication and the timing for surgery in fulminant acute pancreatitis (FAP) are still controversial, our experience of surgical treatment for fulminant acute pancreaUtis may help improve the outcome for patients.Methods The clinical data of twenty-six patients with FAP from January 1, 2001 to October 1,2005 were analyzed. The diagnostic criteria fitted the 2007 Guidelines for the Management of Severe Acute Pancreatitis by the Chinese Medical Association.Results Twenty-six patients with FAP received surgical debridement, with a mortality rate of 42.3% (11/26). The postoperative mortalities in the >72 hour operation group and the <72 hour operation group were highly significantly different (7/8 vs 22.2% (4/18), respectively).Conclusions Early surgery may reduce the intraabdominal pressure and prevent the deterioration of FAP. An operation within 72 hours from the onset of symptoms might decrease the mortality of the disease.  相似文献   
28.
目的 研究降低无轨运输方式施工隧道中空气污染的措施。方法 采用燃油添加剂 ,定期对施工机械进行维修和保养 ,减少发动机空档排气 ,将压入式通风口设置于距掌子面 8~ 10m处 ,保持通风管道密闭通畅致使有效送风。结果 隧道中有害气体CO、NOx及黑烟浓度至少降低 4 6 % ,55%和 4 2 %。结论 采取以上措施能明显改善施工环境的污染状况并减轻对施工人员身体健康的危害  相似文献   
29.
目的 探讨梨状窝癌局部扩展的规律 ,为梨状窝癌的手术治疗提供病理学依据。方法 应用石蜡包埋大体标本连续切片的方法 ,对 2 6例梨状窝癌全喉及次全喉切除的标本进行了观察。结果 位于梨状窝外侧壁的肿瘤 ( 4例 )主要向外侧咽侧壁扩展 ,位于梨状窝内侧壁的肿瘤 ( 5例 )容易向喉腔及对侧梨状窝扩展。累及整个梨状窝 17例。声门旁间隙及甲状软骨是最易受侵犯的喉结构 ,环状软骨受侵较少 ;会厌及会厌前间隙的侵犯未见超过中线 ,声门旁间隙及会厌前间隙的侵犯途径有2个 ,肿瘤沿杓会厌襞向前及在甲状软骨板内侧直接向前侵犯声门旁间隙 ;肿瘤沿杓会厌襞向内上方及在甲状软骨板内侧上部侵入会厌前间隙。结论 会厌前间隙的受侵并不是喉部分切除的禁忌证 ,大部分位于梨状窝外侧壁的肿瘤及部分梨状窝内侧壁的肿瘤保留喉功能是可行的 ;位于梨状窝内侧壁及环后区的肿瘤易在环后区向对侧侵犯 ,对累及环后区的梨状窝癌 (Ⅰ ,Ⅲ型 ) ,应注意肿瘤在环后区粘膜下向对侧侵犯。  相似文献   
30.
胆汁泡蛋白ELISA检测法的建立与初步临床应用   总被引:1,自引:0,他引:1  
目的 建立胆汁泡蛋白快速检测法,筛选有效的胆石症防治手段。方法 获取33.5kd胆汁泡蛋白,通过微量抗原免疫法获得高效价抗体,建立ELISA标准曲线;并应用ELISA法测定正常人、胆石症患者胆汁和血清中泡蛋白含量,同时观察不同溶石防药和利胆冲剂、胆酸钠等对泡蛋白的影响。结果 建立了ELISA标准曲线,其曲线方程为Y=0.035X(r=0.99);正常人胆汁和血清中33.5kd泡蛋白含量都明显较胆固  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