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   121338篇
  免费   11069篇
  国内免费   8700篇
耳鼻咽喉   1007篇
儿科学   1112篇
妇产科学   1168篇
基础医学   14305篇
口腔科学   1994篇
临床医学   16248篇
内科学   17899篇
皮肤病学   1229篇
神经病学   6456篇
特种医学   4341篇
外国民族医学   79篇
外科学   12368篇
综合类   21083篇
现状与发展   41篇
一般理论   6篇
预防医学   8079篇
眼科学   3413篇
药学   12383篇
  131篇
中国医学   7378篇
肿瘤学   10387篇
  2025年   35篇
  2024年   1773篇
  2023年   2720篇
  2022年   5251篇
  2021年   6559篇
  2020年   5135篇
  2019年   4384篇
  2018年   4217篇
  2017年   3777篇
  2016年   3645篇
  2015年   5479篇
  2014年   6714篇
  2013年   5871篇
  2012年   8558篇
  2011年   9419篇
  2010年   5942篇
  2009年   4683篇
  2008年   6066篇
  2007年   5999篇
  2006年   5805篇
  2005年   5867篇
  2004年   3817篇
  2003年   3501篇
  2002年   3010篇
  2001年   2670篇
  2000年   2813篇
  1999年   3007篇
  1998年   2005篇
  1997年   2024篇
  1996年   1555篇
  1995年   1475篇
  1994年   1275篇
  1993年   795篇
  1992年   989篇
  1991年   797篇
  1990年   666篇
  1989年   629篇
  1988年   522篇
  1987年   459篇
  1986年   402篇
  1985年   298篇
  1984年   137篇
  1983年   116篇
  1982年   68篇
  1981年   74篇
  1980年   48篇
  1979年   54篇
  1974年   1篇
  1965年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
W M Xu 《中华肿瘤杂志》1992,14(2):116-118
This report is to demonstrate the antigen-dependent activity of human lung cancer transfer factor (Sp-TF). Sp-TFM was prepared from spleen of mice immunized with the human lung cancer cell line A549. [3H]-leu leukocyte adherence inhibition assay ([3H]-leu-LAI) was modified to identify activity of Sp-TFM. Leukocytes obtained from non-immunized mice were divided into eight groups as follows: 1. Control without TF or antigen; 2. Sp-TFM and antigen of cell line A549 (A549 Ag); 3. Sp-TFM alone; 4. Sp-TFM and ascitic tumor cell H22 antigen of mice (H22Ag); 5. Sp-TFM and antigen of human gastric cancer cell (HGCCAg); 6. Sp-TFM and antigen of human normal lung tissue (NLTAg); 7. Nor special TF of mice (N-TFM) and A549Ag; 8. A549Ag alone. When normal leukocytes were incubated with Sp-TFM and A549 antigen, the leukocytes adherence inhibition index (LAII) was significantly higher than those of the other groups. The different LAII of Sp-TFM to A549Ag and other experimental groups were highly significant (P less than 0.001). The results demonstrated that Sp-TFM could transfer specific cell mediated immunity to non-immune leukocytes. The TF prepared from spleen of goat immunized with antigen from lung cancer of patients (Sp-TFG) showed antigen specific activity as well as Sp-TFM.  相似文献   
42.
人脑胶质瘤逃避免疫监视机制的研究   总被引:2,自引:0,他引:2  
为研究胶质瘤逃避免疫监视的机制,检测了胶质瘤体外细胞系培养上清(SN)抗PHA-P刺激正常人及胶质瘤患者外周血淋巴细胞增殖的作用。证实了胶质瘤可自分泌免疫抑制因子。经抗TGFβ2单抗中和SN试验,TGFβ2免疫组化染色及Northern杂交进一步表明该因子主要成分为TGFβ2并对胶质瘤患者血浆皮质醇,生长激素及儿茶酚胺含量及细胞免疫功能进行检测,发现血浆去甲肾上腺素显著降低,其水平与CD8亚群%呈负相关,与CD4/CD8比值及淋巴细胞增殖率呈正相关。初步提示存在胶质瘤的情况下,神经-免疫调控紊乱,可能起着抑制性调节作用。  相似文献   
43.
Little is known about the quality of pharmacy services provided to the rural elderly population. This exploratory study examines rural/urban and ethnic differences in perceived access to ancillary pharmacy services among elderly people. Two telephone surveys were conducted using directory listings in West Texas to generate a longitudinal sample. Persons aged 65 years and older who were not cognitively impaired were asked to complete the survey. The number of participants in both rounds of the survey was 3,689. Seven ancillary pharmacy services were examined: delivery of medications, medication counseling, written medication information, blood pressure monitoring, blood glucose monitoring, osteoporosis screening, and immunization. The sample was stratified by county of residence (urban, rural, or frontier) and racial/ethnic background. Chi-square tests were performed to detect rural/urban and racial/ethnic differences in access to the seven ancillary services. The association between proficiency in English and access to the services was also examined. Rural residents were more likely than urban residents to report that their pharmacies provide delivery of medications, medication counseling, and immunization services, but they were less likely than their urban counterparts to report that their pharmacies provide blood pressure monitoring. Access to ancillary pharmacy services was reported as poorer by older Hispanic people compared with non-Hispanics. Deficiency in English was significantly related to inequality in reported access to ancillary pharmacy services. It is essential to consider the special needs of rural and Hispanic elderly people to ensure equitable access to ancillary pharmacy services.  相似文献   
44.
45.
Smooth muscle relaxant effect of dehydroindicolactone   总被引:1,自引:0,他引:1  
Dehydroindicolactone, a novel linear furanocoumarin with an 8-substituted side chain carrying a 5-member ring lactone, showed spasmolytic activity in a number of smooth muscle preparations. The spasmolytic activity seems to lie in its ability to block the dihydropyridine-sensitive calcium channel.  相似文献   
46.
47.
Roentgeno-pathological investigation of skeletal fluorosis in rabbits   总被引:3,自引:1,他引:2  
  相似文献   
48.
癌症为深危重疾,对于绝大部分癌症患者,临床普遍采用手术、中医、化疗、放疗、生物等综合方法进行治疗。由于癌症的种类、所处阶段、先前采用的治疗方法以及病人体质等等的不同,求诊时病人的证  相似文献   
49.
A new DRB1 allele, DRB1*0902, has been identified in an individual of the Jing ethnic minority. Its sequence was confirmed by sequencing of PCR products and clones. This allele differed by three nucleotides from DRB1*09012 at positions 157, 161 and 166, and resulted in amino acid motif substitution from VAES to DAEY.  相似文献   
50.
本文建立了体液中右旋儿茶素的RP-HPLC测定方法。采用C_(18)键合相硅胶为填料的固相提取柱进行样品预处理,右旋儿茶素的提取回收率为79.8%.应用二极管阵列检测器对色谱峰纯度进行鉴定。该法精密度好,方法回收率近100%,日内、日间的变异系数为2.4~5.6%,血浓69.6~1160 ng/ml范围内呈线性关系,r=0.9993。家兔静注右旋儿茶素18mg/kg,其药代动力学过程符合二室模型,分布相半衰期为0.129 h,消除相半衰期为1.19h。  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