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   27634篇
  免费   2777篇
  国内免费   1927篇
耳鼻咽喉   172篇
儿科学   346篇
妇产科学   384篇
基础医学   3322篇
口腔科学   497篇
临床医学   3734篇
内科学   4441篇
皮肤病学   257篇
神经病学   1612篇
特种医学   953篇
外国民族医学   21篇
外科学   2829篇
综合类   4278篇
现状与发展   5篇
一般理论   1篇
预防医学   2044篇
眼科学   655篇
药学   2832篇
  24篇
中国医学   1530篇
肿瘤学   2401篇
  2024年   401篇
  2023年   566篇
  2022年   1268篇
  2021年   1610篇
  2020年   1209篇
  2019年   1050篇
  2018年   1060篇
  2017年   978篇
  2016年   851篇
  2015年   1297篇
  2014年   1525篇
  2013年   1386篇
  2012年   2004篇
  2011年   2196篇
  2010年   1265篇
  2009年   991篇
  2008年   1377篇
  2007年   1289篇
  2006年   1288篇
  2005年   1288篇
  2004年   899篇
  2003年   731篇
  2002年   703篇
  2001年   561篇
  2000年   613篇
  1999年   703篇
  1998年   417篇
  1997年   409篇
  1996年   319篇
  1995年   284篇
  1994年   199篇
  1993年   160篇
  1992年   229篇
  1991年   180篇
  1990年   155篇
  1989年   155篇
  1988年   132篇
  1987年   124篇
  1986年   110篇
  1985年   98篇
  1984年   45篇
  1983年   34篇
  1982年   20篇
  1981年   18篇
  1980年   17篇
  1979年   18篇
  1978年   12篇
  1974年   9篇
  1971年   10篇
  1970年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
目的 探讨醒脑静对急性重症一氧化碳 (CO)中毒的催醒作用。方法 在急性重症CO中毒常规综合抢救中加入醒脑静并与常规方法进行对比研究。结果 醒脑静治疗组较常规治疗组清醒时间明显缩短 (P <0 .0 1)。结论 醒脑静可作为急性重症CO中毒病人综合抢救中常规用药。  相似文献   
52.
53.
Tea is a famous beverage that is produced from leaves of Camellia sinensis. Amongst the six major tea categories in China, dark tea is the only one that involves microbial fermentation in the manufacturing process, which contributes unique flavors and functions for the tea. In the recent decade, the reports about the biofunctions of dark teas have increased rapidly. Therefore it may be the proper time to consider dark tea as one potential homology of medicine and food. In this viewpoint, our current understanding of the chemical constituents, biological activities and possible health beneficial effects of dark teas were introduced. Some future directions and challenges to the development perspectives of dark teas were also discussed.  相似文献   
54.

Air samples were collected around industrial parks in Jiangsu, China, to allow the concentrations, profiles, and risk assessment of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), polychlorinated naphthalenes (PCNs), and metals to be investigated. The concentrations of ΣPBDD/Fs and ΣPCNs were 1324.26–2080.98 fg/m3 (11.35–42.57 fg I-TEQ/m3) and 10,404.9–29,322.9 fg/m3 (1.32–7.19 fg I-TEQ/ m3), respectively. The highest concentration of ΣPBDD/Fs and ΣPCNs were observed at site C. PBDD/Fs were mainly dominated by PBDFs. The main contributor to the ΣPBDD/Fs in all samples was 1,2,3,4,6,7,8-HpBDF, which accounted for 25.75%–39.4%. For PCNs, the predominating homologues were tetra-, tri- and penta-CNs, which contributed 30.7%–43.3%, 24.7%–31.0%, and 10.6%–21.6%, respectively. As for metals, the pollution of As, Mn, Cr, and Ni in most samples exceeded National Ambient Air Quality Standards of China. Assessing the risk of inhalation exposure showed that there were potential carcinogenic risks to local residents.

  相似文献   
55.
五种免疫相关性心血管疾病的免疫学研究   总被引:4,自引:0,他引:4  
董波  任忠水 《免疫学杂志》1995,11(3):176-178
对扩张型心肌病、风湿性心脏病,原发性高血压,冠心病及肥厚型心肌病进行外周血清可溶性白细胞介素2受体,T淋巴细胞亚群及自然杀伤细胞活性的检测,并与健康对照组比较,结果显示:DCM组,RHD组及EHT组的sIL-2R明显高于NC组,而DCM、RHD风湿活动组的NK活性低于NC组,EHT组NK活性高于NC组。  相似文献   
56.
Pan J  Zhang QG  Zhang GY 《Neuroscience》2005,131(1):147-159
It has been well documented that the activation of c-Jun N-terminal protein kinase (JNK) pathway and caspase-3 signal are involved in the delayed neuronal cell death in cerebral ischemia. In this study, we first detected the activation pattern of JNK signaling including mixed lineage kinase (MLK)3, mitogen-activated protein kinase kinase (MKK)7 and JNK3 in hippocampal CA1 and CA3/DG regions at various time points after 15 min of ischemia. These results indicated that cerebral ischemia induced the continuous activation of MLK3/MKK7/JNK3 cascade, which all had two active waves only in the CA1 region. We also detected the phosphorylation of JNK substrates c-Jun and Bcl-2, and the activation of a key protease of caspase-3 in CA1 region, which only had one active peak, respectively. Because K252a has recently been shown to be a potent inhibitor of MLK3 activity both in vivo and in vitro, we further examined the possible effects and mechanism of this interesting drug in cerebral ischemia. In our present paper, we found that administration of K252a 20 min prior to ischemia inhibited MLK3/MKK7/JNK3 signaling, Bcl-2 phosphorylation, the activation of c-Jun and caspase-3, but had no significant effects on these protein expressions. Additionally, pretreatment of K252a significantly increased the number of the surviving CA1 pyramidal cells at 5 days of reperfusion. Our results suggest that K252a play a neuroprotective role in ischemic injury via inhibition of the JNK pathway, involving the death effector of caspase-3. Thus, JNK signaling may eventually emerge as a prime target for novel therapeutic approaches to treatment of ischemic stroke, and K252a may serve as a potential and important neuroprotectant in therapeutic aspect in ischemic stroke.  相似文献   
57.
目的:观察鼻咽癌组织中微血管的分布及存在状况,探讨其与鼻咽癌的临床病理联系。方法:采用免疫组织化学S-P法,检测血栓调节蛋白在鼻咽癌血管内皮细胞的表达,进行微血管的定性半定量研究。结果:鼻咽癌组织中微血管的分布不均匀。极性消失。血管呈分支芽状弥漫分布于癌组织中,或呈条索状围绕癌细胞团。微血管的数目与癌细胞的增殖指数屯预后正相关。结论:鼻咽癌组织中微血管数与患者的生存期有关。  相似文献   
58.
Osteopontin is an acidic phosphoprotein containing casein kinase II (CKII) phosphorylatable sites and an acidic amino acid cluster. The metabolically 32P-labelings of both serines and threonines in vitro in osteopontin immunoprecipitated from rat osteoblast-like ROS 17/2.8 cells may suggest that casein kinase II catalyzes this modification. The enzyme occurs in microsomal fractions of rat osteoblast-like ROS 17/2.8 cells. Subcellular fractions containing endoplasmic reticulum and Golgi apparatus were isolated by differential centrifugation and were identified according to their ultrastructures and the presence of marker enzymes such as glucose-6-phosphatase and thiamine pyrophosphatase, respectively. Both fractions phosphorylated the partially dephosphorylated osteopontin and the specific substrate peptide RRREEETEEE. Endoplasmic reticulum-catalyzed peptide phosphorylation was 2.7 times lower than that of Golgi although both endoplasmic reticulum- and Golgi-catalyzed peptide reactions were 50% inhibited by 20 and 100 ng/ml heparin, respectively. Western blot analysis revealed that both fractions contained osteopontin and microsomal CKII. Furthermore, microsomal CKII was immunogold-labeled in endoplasmic reticulum and Golgi apparatus. Heparin inhibition and utilization of [-32P]GTP as a phosphate donor by both fractions confirmed their capacity to phosphorylate osteopontin. The results suggest that microsomal CKII modifies the acidie matrix proteins during transportation. These matrix phosphoproteins may participate in the mineralization process of hard tissues.  相似文献   
59.
王盼 《中国卫生经济》1999,18(11):34-36
本文从产权的角度出发,对当前的医疗机构改革进行了分析,并对医疗机构自主经营、企业化经营过程中可能出现的一些问题,提出了政府作为财产的最终所有者应加强对医疗机构经营状况的监管。  相似文献   
60.
目的观察尿红细胞平均体积(MCV)和尿红细胞分布曲线鉴别血尿来源和性质。方法用COULTER-JT全自动血球计数仪检测40例肾小球性血尿、40例非肾小球性血尿MCV和分布曲线。结果肾小球肾炎MCV为61±14fl,非肾小球肾炎MCV为89±18fl,以MCV<80fl鉴别为肾小球性血尿,敏感性和特异性分别为97.5%和88.2%。分布曲线的特点不同,峰值差异很大。结论测定尿MCV及分布曲线对鉴别血尿来源和性质有重要意义。  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