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   430篇
  免费   76篇
  国内免费   2篇
  2024年   1篇
  2023年   19篇
  2022年   24篇
  2021年   36篇
  2020年   33篇
  2019年   32篇
  2018年   21篇
  2017年   19篇
  2016年   16篇
  2015年   34篇
  2014年   32篇
  2013年   45篇
  2012年   27篇
  2011年   21篇
  2010年   24篇
  2009年   17篇
  2008年   15篇
  2007年   12篇
  2006年   14篇
  2005年   7篇
  2004年   8篇
  2003年   7篇
  2002年   6篇
  2001年   1篇
  1999年   3篇
  1998年   3篇
  1997年   4篇
  1996年   4篇
  1995年   3篇
  1993年   1篇
  1992年   2篇
  1991年   2篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1983年   2篇
  1982年   2篇
  1981年   1篇
  1977年   1篇
  1972年   1篇
排序方式: 共有508条查询结果,搜索用时 171 毫秒
121.
摘要 目的:探讨射频消融术对胃癌肝转移患者胃肠功能、酪氨酸激酶下游蛋白(downstream of tyrosinekinase3, DOK3)、酪氨酸激酶下游蛋白(downstream of tyrosinekinase2, DOK2)水平的影响。方法:选取2017年1月-2020年10月我院收治的90例胃癌肝转移患者作为研究对象,随机将其分为两组,对照组45例,给予原发灶和肝转移切除手术治疗;研究组45例,给予肝转移灶射频消融术治疗,观察两组患者的疗效及并发症率,检测治疗后两组患者胃肠功能、DOK3、DOK2水平。结果:研究组的治疗有效率为88.89 %,高于对照组的71.11 %(P<0.05);研究组患者腹胀腹痛缓解时间、肠鸣音恢复时间、排气时间、排便时间均短于对照组的相应时间(P<0.05);两组患者手术前DOK3、DOK2低表达率对比无明显差异(P>0.05),手术后,研究组患者DOK3、DOK2低表达率明显低于对照组,差异具有统计学意义(P<0.05);研究组患者的并发症发生率为11.11 %,低于对照组的26.67 %(P<0.05);两组患者复发率对比无统计学差异(P>0.05)。结论:对于胃癌肝转移患者采取射频消融术治疗,其效果明显优于传统手术,可促使胃肠功能恢复,改善DOK3、DOK2的表达水平, 降低并发症风险发生。  相似文献   
122.
Loss of Dexras1 in gene-targeted mice impairs circadian entrainment to light cycles and produces complex changes to phase-dependent resetting responses (phase shifts) to light. The authors now describe greatly enhanced and phase-specific nonphotic responses induced by arousal in dexras1?/? mice. In constant conditions, mutant mice exhibited significant arousal-induced phase shifts throughout the subjective day. Unusual phase advances in the late subjective night were also produced when arousal has little effect in mice. Bilateral lesions of the intergeniculate leaflet (IGL) completely eliminated both the nonphotic as well as the light-induced phase shifts of circadian locomotor rhythms during the subjective day, but had no effect on nighttime phase shifts. The expression of FOS-like protein in the suprachiasmatic nucleus (SCN) was not affected by either photic or nonphotic stimulation in the subjective day in either genotype. Therefore, the loss of Dexras1 (1) enhances nonphotic phase shifts in a phase-dependent manner, and (2) demonstrates that the IGL in mice is a primary mediator of circadian phase-resetting responses to both photic and nonphotic events during the subjective day, but plays a different functional role in the subjective night. Furthermore, (3) the change in FOS level does not appear to be a critical step in the entrainment pathways for either light or arousal during the subjective day. The cumulative evidence suggests that Dexras1 regulates multiple photic and nonphotic signal-transduction pathways, thereby playing an essential role modulating species-specific characteristics of circadian entrainment. (Author correspondence: )  相似文献   
123.
Summary

Implantation of ovarian tissue into androgenic gland ablated male prawns, Macrobrachium rosenbergii (de Man) induced the development of ovigerous and ovipositing setae and brood chambers, suggesting that in females, these secondary sexual characteristics are induced by the ovary. This model system has potential for the study of morphological changes associated with breeding in the Decapoda.  相似文献   
124.
125.
A multi‐joystick robotic laser microscope system used to control two optical traps (tweezers) and one laser scissors has been developed for subcellular organelle manipulation. The use of joysticks has provided a “user‐friendly” method for both trapping and cutting of organelles such as chromosomes in live cells. This innovative design has enabled the clean severing of chromosome arms using the laser scissors as well as the ability to easily hold and pull the severed arm using the laser tweezers. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
126.
目的:探讨肝动脉化疗栓塞(TACE)联合射频消融(RFA)对中晚期肝癌患者血清肿瘤活性因子、肝功能和预后的影响。方法:选取2012年2月~2016年6月期间我院收治的中晚期肝癌患者103例,根据随机数字表法将患者分为对照组(n=51)和研究组(n=52),对照组患者给予RFA治疗,研究组给予TACE联合RFA治疗,比较两组临床总有效率,比较两组治疗前后肝功能、血清肿瘤活性因子水平,统计两组患者并发症情况和预后。结果:治疗后研究组临床总有效率为53.85%(28/52),高于对照组患者的33.33%(17/51)(P0.05)。两组患者治疗后总胆红素(TBIL)、丙氨酸转氨酶(ALT)、氨基酸转氨酶(AST)较治疗前降低(P0.05),但两组治疗后TBIL、ALT、AST比较差异无统计学意义(P0.05)。两组患者治疗后甲胎蛋白(AFP)、糖类抗原199(CA199),基质金属蛋白酶(MMP)均较治疗前降低,且研究组低于对照组(P0.05)。两组患者并发症发生率比较无差异(P0.05)。研究组患者治疗后1年、2年复发率低于对照组,生存率高于对照组(P0.05)。结论:TACE联合RFA治疗中晚期肝癌,疗效确切,可有效降低血清肿瘤活性因子水平,未加重肝功能损伤,且可改善患者的预后。  相似文献   
127.
目的:探讨等离子低温射频消融术联合鼻内镜对慢性鼻窦炎(CRS)患者嗅觉功能及血清炎症介质的影响。方法:选取2016年3月~2018年7月期间我院收治的CRS患者127例,根据手术方式的不同将患者分为A组(n=62,鼻内镜手术)和B组(n=65,等离子低温射频消融术联合鼻内镜手术),术后随访1年,比较两组患者临床疗效、症状评分、嗅觉功能、血清炎症介质及并发症情况。结果:B组术后1年的临床总有效率为87.69%(57/65),高于A组的72.58%(45/62)(P0.05);术后3个月B组的嗅觉功能分布优于A组(P0.05);两组患者术后3个月鼻塞、头面部胀痛、流脓涕、鼻涕倒流、头痛等症状评分均降低,且B组低于A组(P0.05)。两组患者术后1周血清白介素-5(IL-5)、白介素-17(IL-17)以及肿瘤坏死因子-α(TNF-α)均降低,且B组低于A组(P0.05)。两组术后并发症发生率比较无差异(P0.05)。结论:CRS在鼻内镜的基础上联合等离子低温射频消融术治疗的疗效显著,能够有效改善患者嗅觉功能和临床症状,抑制机体炎性反应的同时不增加并发症发生率。  相似文献   
128.
摘要 目的:研究超声造影在甲状腺结节鉴别诊断及良性结节微波消融治疗中的应用价值。方法:选取2015年1月~2018年2月我院收治的甲状腺结节患者100例作为研究对象,所有纳入对象均进行超声造影检查,分析甲状腺结节的超声造影特征,并与病理诊断结果进行对照。此外,将甲状腺良性结节患者以随机抽签法分成超声造影组31例和常规超声组30例。超声造影组微波消融治疗前后均予以超声造影配合,常规超声组微波消融治疗前后均予以常规超声配合。比较两组治疗前后甲状腺结节造影情况以及术后1年结节复发情况。结果:甲状腺恶性结节增强强度为低增强、增强模式为不均匀、无环绕增强占比均高于良性结节(均P<0.05)。以病理诊断为金标准,超声造影诊断恶性甲状腺结节的灵敏度为92.31%、特异度为78.69%、准确度为84.00%。治疗后超声造影组甲状腺结节最长径、体积均低于常规超声组(均P<0.05)。超声造影组术后1年结节复发率为0.00%,低于常规超声组的16.67%(P<0.05)。结论:超声造影应用于甲状腺结节鉴别诊断的价值较高,且结合微波消融治疗良性结节的效果明显,预后理想,值得临床推广应用。  相似文献   
129.
The role of antennae and maxillary palps in mediating food preferences by Manduca sexta (Johan.) (Lepidoptera: Sphingidae) was examined. Fifth‐instar larvae, having different chemosensory organs remaining after microsurgery, were tested in two‐choice feeding assays using three solanaceous host species Lycopersicon esculentum (Mill.), Datura innoxia (Mill.), and Solanum pseudocapsicum (L.), an acceptable non‐host Raphanus sativus (L.) (Cruciferae), and an unacceptable non‐host Pelargonium hortorum (L.H. Bailey) (Geraniaceae). Larvae had a choice between leaf discs of two plant species or between one species and moist filter paper discs (water). The antennae are fully competent in mediating normal (unimpaired) food preferences for S. pseudocapsicum vs. water and P. hortorum vs. water. Thus, the antennae alone can mediate both acceptance and rejection behaviour. The latter is the first report of such a function in M. sexta. The antennae are partly competent (reduced preference) for S. pseudocapsicum vs. P. hortorum. No antennal competence could be demonstrated using the other plant species tested. The antennae alone are either partly needed (R. sativus vs. water) or not necessary to elicit normal food preferences for the plant species tested. The maxillary palps are fully competent in mediating normal food preference for S. pseudocapsicum vs. water, and D. innoxia vs. water. The palps are partly competent for S. pseudocapsicum vs. P. hortorum and incompetent for the other plant species tested. Thus, the maxillary palps alone could only mediate acceptance behaviour in this study. The need of the maxillary palps in normal food preferences could not be demonstrated. Interestingly, the maxillary palps alone can mediate food preferences for two normally rejected plants, R. sativus and P. hortorum. Similar results are reported for two other non‐host plant species, Vigna unguiculata (Walp.) (Leguminosae) and Vinca rosea (L.) (Apocynaceae). Perhaps, the maxillary palps inform M. sexta mostly about feeding stimulatory chemicals common to most plant species.  相似文献   
130.
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