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   3587篇
  免费   441篇
  国内免费   224篇
耳鼻咽喉   10篇
儿科学   20篇
妇产科学   17篇
基础医学   268篇
口腔科学   18篇
临床医学   110篇
内科学   198篇
皮肤病学   44篇
神经病学   55篇
特种医学   43篇
外科学   98篇
综合类   551篇
预防医学   108篇
眼科学   24篇
药学   1591篇
  2篇
中国医学   1073篇
肿瘤学   22篇
  2024年   24篇
  2023年   59篇
  2022年   103篇
  2021年   135篇
  2020年   143篇
  2019年   116篇
  2018年   101篇
  2017年   148篇
  2016年   182篇
  2015年   188篇
  2014年   352篇
  2013年   274篇
  2012年   285篇
  2011年   297篇
  2010年   198篇
  2009年   186篇
  2008年   170篇
  2007年   202篇
  2006年   160篇
  2005年   145篇
  2004年   113篇
  2003年   98篇
  2002年   70篇
  2001年   60篇
  2000年   37篇
  1999年   34篇
  1998年   28篇
  1997年   30篇
  1996年   23篇
  1995年   19篇
  1994年   18篇
  1993年   19篇
  1992年   14篇
  1991年   15篇
  1990年   15篇
  1989年   10篇
  1988年   20篇
  1987年   12篇
  1986年   19篇
  1985年   18篇
  1984年   12篇
  1983年   14篇
  1982年   8篇
  1981年   16篇
  1980年   15篇
  1979年   6篇
  1978年   6篇
  1977年   8篇
  1976年   9篇
  1970年   5篇
排序方式: 共有4252条查询结果,搜索用时 15 毫秒
91.
BACKGROUND Interdigestive migrating motor complexes(MMC)produce periodic contractions in the gastrointestinal tract,but the exact mechanism of action still remains unclear.Intramuscular interstitial cells of Cajal(ICC-IM)participate in gastrointestinal hormone and neuromodulation,but the correlation between ICCIM and MMC is also unclear.We found that xiangbinfang granules(XBF)mediated the phase III contraction of MMC.Here,the effects of XBF on gastric antrum motility in W/Wv mice and the effects of ICC-IM on gastric antrum MMC are reported.AIM To observe the effects of ICC-IM on gastric antrum motility and to establish the mechanism of XBF in promoting gastric antrum motility.METHODS The density of c-kit-positive ICC myenteric plexus(ICC-MP)and ICC-IM in the antral muscularis of W/Wv and wild-type(WT)mice was examined by confocal microscopy.The effects of XBF on gastric antrum slow waves in W/Wv and WT mice were recorded by intracellular amplification recording.Micro-strain-gauge force transducers were implanted into the gastric antrum to monitor the MMC and the effect of XBF on gastric antrum motility in conscious W/Wv and WT mice.RESULTS In the gastric antrum of W/Wv mice,c-kit immunoreactivity was significantly reduced,and no ICC-IM network was observed.Spontaneous rhythmic slow waves also appeared in the antrum of W/Wv mice,but the amplitude of the antrum slow wave decreased significantly in W/Wv mice(22.62±2.23 mV vs 2.92±0.52 mV,P<0.0001).MMCs were found in 7 of the 8 WT mice but no complete MMC cycle was found in W/Wv mice.The contractile frequency and amplitude index of the gastric antrum were significantly increased in conscious WT compared to W/Wv mice(frequency,3.53±0.18 cpm vs 1.28±0.12 cpm;amplitude index,23014.26±1798.65 mV·20 min vs 3782.16±407.13 mV·20 min;P<0.0001).XBF depolarized smooth muscle cells of the gastric antrum in WT and W/Wv mice in a dose-dependent manner.Similarly,the gastric antrum motility in WT mice was significantly increased after treatment with XBF 5 mg(P<0.05).Atropine(0.1 mg/kg)blocked the enhancement of XBF in WT and W/Wv mice completely,while tetrodotoxin(0.05 mg/kg)partially inhibited the enhancement by XBF.CONCLUSION ICC-IM participates in the regulation of gastric antrum MMC in mice.XBF induces MMC III-like contractions that enhance gastric antrum motility via ICCIM in mice.  相似文献   
92.
目的在大肠埃希菌中高效表达及纯化弓形虫GRA6抗原,为制作弓形虫感染基因工程诊断试剂盒奠定基础.方法将重组pGEX-GRA6表达载体转化大肠埃希菌BL21-Codon Plus(DE3)-RP菌株,在异丙基硫代-β-D半乳糖苷(IPTG)诱导下表达.超声破壁后,通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)分析表达产物的表达形式,并对表达产物以硫酸铵沉淀、Sephedax G50脱盐和GST亲和层析柱进行目的蛋白的纯化.通过Western blotting检测其纯化的重组抗原的免疫反应性.结果GRA6以融合蛋白(GST-GRA6)的形式在大肠埃希菌中得到了高效表达.对表达产物可溶性分析表明,表达蛋白在上清液中和包涵体中均有表达.在上清液中表达的可溶性蛋白经纯化后蛋白纯度可达90%以上.Western blotting分析表明纯化蛋白能被弓形虫感染的人血清所识别.结论GRA6在大肠埃希菌中得到了高效表达,重组抗原经纯化后能特异性地被弓形虫感染者血清所识别.  相似文献   
93.
目的 探讨清热理气冲剂对实验性胆汁反流性胃炎(BRG)大鼠血浆内皮素(ET)和降钙素基因相关肽(CGRP)的影响。方法 60只大鼠随机分为A组(中药等效剂量组),B组(中药大剂量组),C组(西沙必利等效剂量组),D组(枸橼酸铋钾等效剂量组),E组(病理对照组)和F组(正常对照组)。除F组外,其余各组大鼠应用胆汁灌胃导致胃黏膜损害。2W后分别应用清热理气冲剂等效剂量、大剂量、西沙必利、枸橼酸铋钾处理。实验第4周观察胆汁反流性胃炎胃黏膜病理形态和应用放免法测定血浆ET和CGRP含量。结果 F组可见黏膜下层充血水肿,胃小凹增生,肠上皮化生,炎性细胞浸润等,而A组和B组胃黏膜组织形态显著改善。F组电镜观察到胃黏膜细胞问的紧密连接受损,线粒体肿胀,粗面内质网扩张,微绒毛变短或丢失,A组和B组的超微结构明显的改善。A组和B组血浆ET明显低于E组(P〈0.01)。A组和B组血浆CGRP明显高于E组(P〈0.01)。结论 清热理气冲剂可以减轻胃黏膜损伤,通过影响血浆ET和CGRP相关肽含量而达到治疗BRG目的。  相似文献   
94.
目的分析裸花紫珠颗粒联合替硝唑氯化钠注射液、头孢呋辛钠抗菌药物治疗慢性盆腔炎(CPID)患者的临床效果。方法选取2017年1月~2018年12月某院CPID患者126例,随机分为研究组(n=63)与对照组(n=63),对照组予以替硝唑氯化钠注射液、头孢呋辛钠治疗,研究组在对照组基础上加用裸花紫珠颗粒。对比两组疗效、临床症状改善时间(发热、白带异常、下腹痛)及治疗前后血清炎性因子水平[白细胞介素-1β(IL-1β)、单核细胞趋化蛋白-1(MCP-1)]变化。结果研究组总有效率92.06%(58/63)较对照组79.37%(50/63)高(P<0.05);研究组发热、白带异常、下腹痛改善时间较对照组短(P<0.05);治疗后,研究组血清IL-1β、MCP-1水平较对照组低(P<0.05)。结论裸花紫珠颗粒联合替硝唑氯化钠注射液、头孢呋辛钠抗菌药物治疗CPID患者效果显著,可减轻炎症反应,改善患者临床症状。  相似文献   
95.
目的:探讨智能分布式药品柜管控系统在儿童重症监护病房(PICU)药品管理中的作用。方法:临床药师参与完善智能分布式药品柜管控系统的组成功能、工作流程并比较使用前后的工作模式及数据。结果:智能分布式药品柜管控系统与医院信息系统(HIS)对接后,实现了药品补充、取药、盘点、监控等信息化的管理。与使用前比较,智能分布式药品柜管控系统的应用降低了库存误差率(P<0.05),提高了账物相符率(P<0.05),节约了盘点时间(P<0.01)。结论:智能分布式药品柜管控系统确保了药品的存储安全,降低了用药错误,明确了责任分工,提高了经济效益,为病区的药品管理提供了新的方式与思路。  相似文献   
96.
Two cases of small cell “undifferentiated” carcinoma (oat cell carcinoma) of the lung with dual neurosecretory and squamous differentiation are reported. One was treated with various regimens of chemotherapy and radiotherapy; the other was untreated at the time of biopsy. By electron microscopy, the same tumor cells showed membrane-bound, dense-core, neurosecretory-type granules and bundles of tonofibrils denoting squamous differentiation. This dual differentiation underlies the difficulty of ascribing an exclusively neural histogenesis to small cell carcinomas with neurosecretory-type granules. It is possible that entoderm-associated neuroectodermal tumors develop features of autochthonous entodermal tumors as a result of microenvironmental influences. An alternative hypothesis would be that small cell tumors are derived from basal reserve bronchoepithelial cells with pluripotentialities.  相似文献   
97.
《Ultrastructural pathology》2013,37(3-4):279-286
Classically, ultrastructural examination of alveolar soft part sarcoma reveals large, dramatic, rhomboid to needlelike crystals with a characteristic substructure. In this study of four cases of alveolar soft part sarcoma, only two exhibited large crystals, which were rare. All four cases, however, exhibited round, electron-dense granules, and in the two cases without large crystals these granules rarely exhibited elongation with the characteristic substructure of alveolar soft part sarcoma that permits definitive diagnosis. Two of these cases had been previously studied at other institutions, where crystals were not identified ultrastructurally and electron microscopy was considered noncontributory. Large crystals, then, may be rare or absent in alveolar soft part sarcoma. Careful search may be necessary to find granules with the characteristic periodic substructure.  相似文献   
98.
99.
Abnormal expression of long interspersed element-1 (LINE-1) has been implicated in drug resistance, while our previous study showed that chemotherapy drug paclitaxel (PTX) increased LINE-1 level with unknown mechanism. Bioinformatics analysis suggested the regulation of LINE-1 mRNA by drug-induced stress granules (SGs). This study aimed to explore whether and how SGs are involved in drug-induced LINE-1 increase and thereby promotes drug resistance of triple negative breast cancer (TNBC) cells. We demonstrated that SGs increased LINE-1 expression by recruiting and stabilizing LINE-1 mRNA under drug stress, thereby adapting TNBC cells to chemotherapy drugs. Moreover, LINE-1 inhibitor efavirenz (EFV) could inhibit drug-induced SG to destabilize LINE-1. Our study provides the first evidence of the regulation of LINE-1 by SGs that could be an important survival mechanism for cancer cells exposed to chemotherapy drugs. The findings provide a useful clue for developing new chemotherapeutic strategies against TNBCs.  相似文献   
100.
目的:分析小儿肺咳颗粒联合孟鲁司特钠治疗小儿肺炎的疗效。方法:选取2018年1月至2019年6月广州中医药大学第一附属医院白云医院儿科收治的小儿肺炎患儿50例作为研究对象,随机分为观察组和对照组,每组25例。对照组行常规治疗+孟鲁司特钠,观察组在其基础上联用小儿肺咳颗粒,比较2组疗效。结果:治疗前比较,2组睡眠质量评分比较差异无统计学意义(P>0.05),观察组体温恢复时间、咳嗽咳痰改善和肺部啰音消失时间均短于对照组(P<0.05);治疗后2周、4周2组PSQI得分较治疗前明显下降且观察组PSQI得分低于对照组(P<0.05)。结论:在小儿肺炎治疗中联合小儿肺咳颗粒和孟鲁司特钠可以缩短患者症状恢复时间,提高睡眠质量,值得应用。  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