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   39618篇
  免费   3729篇
  国内免费   2657篇
耳鼻咽喉   203篇
儿科学   508篇
妇产科学   603篇
基础医学   4920篇
口腔科学   711篇
临床医学   4841篇
内科学   6527篇
皮肤病学   364篇
神经病学   2349篇
特种医学   1335篇
外国民族医学   23篇
外科学   4348篇
综合类   5899篇
现状与发展   12篇
一般理论   4篇
预防医学   2316篇
眼科学   980篇
药学   4062篇
  15篇
中国医学   1898篇
肿瘤学   4086篇
  2024年   102篇
  2023年   568篇
  2022年   1341篇
  2021年   1702篇
  2020年   1393篇
  2019年   1231篇
  2018年   1320篇
  2017年   1212篇
  2016年   1154篇
  2015年   1784篇
  2014年   2137篇
  2013年   1876篇
  2012年   2979篇
  2011年   3102篇
  2010年   1884篇
  2009年   1529篇
  2008年   2153篇
  2007年   2131篇
  2006年   1963篇
  2005年   2044篇
  2004年   1407篇
  2003年   1354篇
  2002年   1109篇
  2001年   905篇
  2000年   1029篇
  1999年   1083篇
  1998年   646篇
  1997年   692篇
  1996年   513篇
  1995年   486篇
  1994年   438篇
  1993年   301篇
  1992年   319篇
  1991年   329篇
  1990年   297篇
  1989年   256篇
  1988年   227篇
  1987年   218篇
  1986年   189篇
  1985年   139篇
  1984年   106篇
  1983年   80篇
  1982年   34篇
  1981年   46篇
  1980年   29篇
  1979年   33篇
  1978年   25篇
  1977年   19篇
  1976年   18篇
  1973年   13篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
4-Aminopyridine (4-AP) induced an atropine- and tetrodotoxin (TTX)-insensitive contraction (resistant contraction), in a concentration-dependent manner, in the isolated jejunum of rabbits. The failure of specific antagonists of histamine, serotonin and substance P to affect this resistant contraction ruled out the participation of histamine, serotonin and/or substance P. Antiserum against neuropeptide Y (NPY) reduced this resistant contraction in a concentration-dependent manner and inhibited the action of 4-AP totally at a high concentration (1.25% dilution) whereas normal serum lacked this ability. This suggested that the release of NPY was involved in this 4-AP-induced resistant contraction. Radioimmunoassay of NPY-like immunoreactivity in isolated synaptosomal preparations indicated that 4-AP possessed the ability to induce the release of NPY. However, guanethidine did not affect the actions of 4-AP, indicating that NPY is released mainly from non-adrenergic nerves. Our results indicate that 4-AP induces the release of NPY from non-adrenergic nerves to produce an atropine- and TTX-resistant contraction in the isolated jejunum of rabbits.  相似文献   
102.
103.
本文报告40例癫痫病人采用手术治疗。30例作了CT检查、脑电图检查,6例作脑电地形图检查,对手术定位有较大帮助。术中用脑皮层电图监测,有效地提高了癲痫源灶的切除率,手术有效者34例(85.0%)。作者还应用了胼胝体切开术,从病灶切除的病理所见,癫痫的外科治疗应引起神经外科的重视。  相似文献   
104.
We have previously reported that the J774A.1 macrophage-like tumor cell line produces two potent monokines which stimulate the growth of osteoblasts and chondrocytes. These growth factors, which have an affinity for heparin-agarose, have been termed HEP I (a 30 Kd PDGF-like molecule) and HEP II (an approximately 20 Kd molecule), respectively, based on their elution profile. Unlike HEP I, HEP II does not stimulate the growth of fibroblasts. Extensive biological and chromatographic studies disclosed that HEP II appears to be a unique bone cell mitogen unlike any known growth factor, including the FGFs, IL-1s, and TNFs, EGF, IGF-I and -II, TGF-beta, beta 2 microglobulin, G-CSF, CSF-1 and GM-CSF. To characterize more fully the effects of the macrophage-derived monokines on osteoblast growth and function, clones were derived from calvaria explant cultures. Two clones, SDFRC-2.05 and SDFRC-3, were developed and found to exhibit osteoblastic characteristics, including high levels of alkaline phosphatase, synthesis of type I but not type III collagen, and an increased intracellular cAMP production in response to PTH. The SDFRC-3 cells exhibited a polygonal morphology like that of the explant-derived cells while SDFRC-2.05 cells exhibited a more fibroblastic morphology. When tested on the explant cultures and clones, HEP I and HEP II were found to stimulate DNA synthesis and increase protein per culture, but decreased alkaline phosphatase activity. Clone SDFRC-3 was found to be more responsive to HEP II than clone SDFRC-2.05. Both monokines were found to be more potent mitogens for bone cells than TGF-beta. HEP II, but not HEP I or TGF-beta, induced a transformation of bone cells from a polygonal to a fibroblastic morphology, suggesting the induction of migration prior to proliferation. Thus, macrophages may be responsible not only for bone repair but also for ensuring the linkage of bone formation to resorption during physiological remodeling.  相似文献   
105.
106.
From June 1979 to July 1987, 84 acute burned patients with localized deep wounds involving tendon, nerve, vessel, bone and joint were treated by utilising 26 types of island axial-pattern cutaneous or musculocutaneous flaps. All flaps survived completely with a primary healing rate of 91.4%. All patients were divided into 'urgent' (within 48 hours), 'early' (within 2 weeks), or 'infected' groups according to the time interval between the burn injury and the surgery conducted. The primary healing rates for each groups were 100%, 94%, and 86% respectively. No significant differences exist between the axial-pattern cutaneous flap and musculo-cutaneous groups. The measures for minimizing infection including thorough debridement, groups. The measures for minimizing infection including thorough debridement, avoiding of circulatory compromises of the flaps, effectively postoperative drainage, and the use of antibiotics were discussed. Four types of newly developed axial-pattern cutaneous flaps as well as a super-long latissimus dorsi-external oblique abdominis-rectus abdominis combined musculocutaneous flaps were presented.  相似文献   
107.
高浓度瘦素自分泌诱导脂肪细胞瘦素抵抗的研究   总被引:1,自引:0,他引:1  
李小林  赵锋  巫国辉  袁铿 《中国美容医学》2007,16(12):1696-1699
目的:观察高浓度瘦素对人脂肪细胞分解代谢及脂肪蓄积的直接影响,探讨瘦素自分泌调节在肥胖发生中的作用。方法:取正常成人皮下脂肪组织,常规提取和培养前脂肪细胞,待细胞融合后诱导分化为脂肪细胞后分为二组:低浓度组、高浓度组;分别培养于瘦素终浓度为100ng/ml、1000ng/ml的培养液a中。于培养48h、72h收集培养液检测游离脂肪酸和甘油的浓度,取脂肪细胞行油红O染色并图像分析计算脂肪细胞中脂肪颗粒的积分光密度。结果:与低浓度组相比,瘦素作用48h、72h后,高浓度组培养液中游离脂肪酸浓度均下降[(0.16711±0.011900)mmol/L VS(0.20589±0.008738)mmol/L,(0.17544±0.013920)mmol/L VS(0.23567±0.026220)mmol/L,甘油含量均减少(28.1733±0.91377)μmol/L VS(30.2456±0.30084)μmol/L,(28.9367±0.79530)μmol/L VS(31.8567±0.79024)μmol/L],而脂肪颗粒积分光密度则升高(461136.89±12049.947 VS418570.33±5668.129,441566.56±5921.602 VS 390133.67±7001.304)。结论:高浓度瘦素长时程作用脂肪细胞,可延缓脂肪分解代谢,增加脂肪蓄积。高浓度瘦素经自分泌诱导脂肪细胞产生瘦素抵抗,可能对肥胖发生有重要影响。  相似文献   
108.
目的 应用交联处理的胶原支架,来减缓其降解过多、易收缩变形、机械性能不足等缺点.方法 采用冷冻-冻干法构建胶原/壳聚糖多孔支架,并通过戊二醛交联构建具有良好抗细胞收缩稳定性和细胞相容性的胶原支架.通过测定不同培养时间各类支架的尺寸变化,研究了戊二醛交联对支架抗细胞收缩能力的影响.结果 戊二醛交联后的胶原/壳聚糖支架未见明显收缩,其细胞活性也始终高于干热交联支架.结论 戊二醛能有效地提高胶原基支架的抗细胞收缩能力,并保持其良好的生物相容性.  相似文献   
109.
110.
谢芳  丛莘 《护理研究》2005,19(28):2576-2577
[目的]观察针灸结合刺络放血法治疗骨性膝关节炎的临床疗效和护理效果.[方法]对52例骨性膝关节炎病人采用针灸结合刺络放血治疗,并给予活动与功能锻炼指导,将治疗前和治疗20 d后病人疼痛程度、晨僵、肿胀、日常步行活动能力以及疼痛缓解时间进行分级评分比较.[结果]治疗前后各项指标的差异均有统计学意义(P<0.01).[结论]针灸配合刺络放血法结合活动指导及功能锻炼治疗骨性膝关节炎,能够快速缓解病人关节疼痛、肿胀、晨僵,改善步行能力,从而提高生活质量.  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