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   2055篇
  免费   136篇
  国内免费   45篇
耳鼻咽喉   16篇
儿科学   95篇
妇产科学   26篇
基础医学   142篇
口腔科学   42篇
临床医学   284篇
内科学   331篇
皮肤病学   44篇
神经病学   59篇
特种医学   288篇
外科学   310篇
综合类   205篇
预防医学   139篇
眼科学   16篇
药学   117篇
  2篇
中国医学   32篇
肿瘤学   88篇
  2022年   30篇
  2021年   33篇
  2020年   31篇
  2018年   22篇
  2017年   24篇
  2016年   18篇
  2015年   35篇
  2014年   52篇
  2013年   76篇
  2012年   77篇
  2011年   86篇
  2010年   90篇
  2009年   107篇
  2008年   67篇
  2007年   80篇
  2006年   81篇
  2005年   53篇
  2004年   49篇
  2003年   50篇
  2002年   46篇
  2001年   37篇
  2000年   28篇
  1999年   28篇
  1998年   82篇
  1997年   74篇
  1996年   72篇
  1995年   67篇
  1994年   41篇
  1993年   50篇
  1991年   19篇
  1990年   14篇
  1989年   30篇
  1988年   42篇
  1987年   39篇
  1986年   29篇
  1985年   33篇
  1984年   19篇
  1983年   24篇
  1982年   16篇
  1980年   16篇
  1977年   15篇
  1976年   14篇
  1963年   17篇
  1960年   14篇
  1959年   22篇
  1958年   29篇
  1957年   19篇
  1956年   30篇
  1955年   42篇
  1954年   35篇
排序方式: 共有2236条查询结果,搜索用时 0 毫秒
61.
目的观察半导体激光联合药物治疗带状疱疹的疗效。方法将97例带状疱疹患者随机分成2组。对照组45例单纯药物治疗(静脉注射5%葡萄糖注射液250 ml加入阿昔洛韦0.5 g,每日2次;本院自制中药冷湿敷患处,每次15 min,每日2次)。治疗组在上述药物治疗基础上加用半导体激光照射受损的神经根部和皮损部位。疗程7 d。结果治疗组与对照组治疗后病情积分均有所下降(P<0.01),治疗组的病情积分下降明显大于对照组(P<0.01);治疗组的疼痛积分明显下降(P<0.01);对照组的疼痛积分无明显下降,治疗组有效率大于对照组,后遗神经痛发生率低于对照组。结论半导体激光联合药物治疗带状疱疹疗效优于单纯药物治疗,且可明显减轻疼痛症状,降低后遗神经痛发生率。  相似文献   
62.
63.
Chronic granulocytic leukaemia (CGL) cells which contained a high concentration of unsaturated folate binding protein were incubated in suspension culture for a period of 5 h. Cell samples were periodically assayed for binder and these demonstrated active synthesis which was inhibited by puromycin, cyclo heximide, N-ethylmaleimide, and by incubation at 4 degrees C, but not by actinomycin D. Folate binding activity could also be demonstrated in the culture medium and this increased with the duration of incubation. This release of binder was inhibited by culturing the cells at 4 degrees C and by the addition of N-ethylmaleimide, but not by actinomycin D, puromycin, or cycloheximide. When the pre- and post-culture cell lysates were saturated with tritiated folic acid ([3H]PteGlu) and subjected to chromatography on DEAE-agrarose, approximately half of the bound folate eluted with 0.001 M phosphate buffer at pH 6.0 and the other half eluted with 0.2 M buffer at pH 7.2. The culture medium and plasma from this patient with CGL was well as serum from two normal subjects saturated with [3H]PteGlu and similarly chromatographed contained primarily the acidic binder and much less of the binder eluting with the low molarity buffer. Since a folate binding protein immunochemically similar to the binder in CGL cells has been identified in the serum of non-leukaemic subjects, these experiments suggest that the source of circulating folate binding protein may be the immature granulocyte.  相似文献   
64.
The kidneys in paroxysmal nocturnal hemoglobinuria   总被引:6,自引:0,他引:6  
Long-term study of 21 PNH patients revealed an unexpectedly high incidence of functional and anatomic renal abnormalities. Most patients demonstrated varying degrees of hematuria and proteinuria distinct from hemoglobinuria. Evaluation of renal function revealed hyposthenuria, abnormal tubular function, and declining creatinine clearance. Radiologically these patients had enlarged kidneys, cortical infarcts, cortical thinning, and papillary necrosis which were confirmed by autopsy studies. Hypertension developed in eight patients. Urinary tract infection was uncommon. The renal findings bear striking similarity to those of sickle cell anemia. Contrary to the usual opinion, out studies clearly showed evidence of widespread renal pathology in PNH most likely due to repeated microvascular thrombosis similar to the venous thrombosis involving other organs in this disorder.  相似文献   
65.
目的分析5例脊髓延髓肌萎缩症患者的临床特征,以便临床医生对该病的认识。方法收集基因确诊的5例脊髓延髓肌萎缩症患者的临床资料,分析其临床特点及血清性激素、各生化指标水平、脑脊液及肌电图特点。结果脊髓延髓肌萎缩症患者青年发病,病情进展缓慢。神经系统表现为以肢体近端和延髓部受累为主的瘫痪。舌肌受累较早,运动功能损害较轻。血清睾酮(969.3±234.9ng/dl)、雌二醇(57.1±5.3pg/ml)水平增高,男性乳腺发育出现在病史较长的患者。三核苷酸(CAG)重复序列数目43~51(平均47.2±3.6pg/ml)。患者的肌酸激酶(CK,481.8±264.8 IU/L)均增高,脑脊液检查均正常。肌电图为广泛神经源性损害。结论脊髓延髓肌萎缩症患者的早期症状不典型,易误诊,临床特征为青年起病,缓慢加重,以肢体近端无力为主的瘫痪。  相似文献   
66.
67.
Sixteen patients with suspected cerebral metastases were studied with magnetic resonance (MR) imaging before and after the intravenous administration of 0.1 mmol/kg of gadolinium diethylenetriaminepenta-acetic acid. The images were interpreted blindly by two neuroradiologists; all clinical, radiologic (computed tomographic and MR imaging), and pathologic data were reviewed to arrive at a final "best diagnosis," which was then compared with the prior blinded interpretations. Of seven patients found to have multiple metastases, six (86%) had at least one tumor nodule depicted by postinfusion MR imaging that was missed by one or both observers on review of preinfusion images alone. Lesions missed on preinfusion studies were usually small nodules hidden by or not detected next to regions of high-signal edema thought to be related to the adjacent tumor nodule. The authors believe that contrast enhancement improves detection of metastatic foci with MR imaging and that the findings indicate broader implications for the detection of multiple lesions from other causes.  相似文献   
68.
目的研究MR氢质子波谱(^1H-MRS)成像在神经上皮组织肿瘤分级中的价值。方法52例颅内神经上皮组织肿瘤患者,低级别29例,高级别23例,均行MRI及^1H-MRS检查。结果52例中,Ⅱ级9例,Ⅲ级11例,Ⅳ级12例,将Ⅱ级列为低级别组,Ⅲ级、Ⅳ级为高级别组,脂质(Lip)[乳酸(Lac)]/肌酸(Cr)、Lip(Lac)/N-乙酰天门冬氨酸(NAA)、Lip(Lac)/胆碱化合物(Cho),Lip(Lac)在组间差异有统计学意义,低级别组各代谢物比值中位数分别为0.14、0.16、0.09、0.32,高级别组各代谢物中位数分别为1.64、1.24、0.87、1.68。Lip(Lac)/Cr≤0.425为低级别肿瘤,Lip(1ac)/Cr>0.425为高级别肿瘤,诊断敏感度、特异度、阳性予测值、阴性预测值分别为87.0%、96.6%、95.2%、90.3%。常规MR图像诊断肿瘤级别敏感度、特异度、阳性予测值、阴性预测值分别为87.0%、82.8%、80.0%、88.9%。结论^1H-MRS在神经上皮组织肿瘤分级中有一定的价值,常规MR图像结合MRS可明显提高诊断准确率。  相似文献   
69.
70.
目的:检测急性非淋巴细胞白血病患者白血病细胞表面MHC—Ⅱ类分子和共刺激分子的表达情况。方法:采集骨髓中白血病细胞大于70%的27例初诊或复发息者骨髓细胞。荧光抗体标记。应用流式细胞仪进行HLA—DR、CD80(B7-1)和CI)和(B7—2)免疫标记检测。结果:27例病人除M3型表达明显低于其他各型外。HLA—DR抗原的表达均较高。其中M2型最高为90%;CD80阳性率很低,最高为M1型只有5%。其余均在l%~3%之间。CD86的表达高于CD80,最高为M5型为48%,最低为M6型为11%。结论:白血病细胞表面共刺激分子表达以CD80缺乏为主。  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