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   438篇
  免费   32篇
  国内免费   12篇
  2023年   3篇
  2022年   1篇
  2021年   9篇
  2020年   12篇
  2019年   14篇
  2018年   12篇
  2017年   8篇
  2016年   16篇
  2015年   9篇
  2014年   18篇
  2013年   24篇
  2012年   15篇
  2011年   25篇
  2010年   23篇
  2009年   26篇
  2008年   17篇
  2007年   26篇
  2006年   27篇
  2005年   21篇
  2004年   18篇
  2003年   13篇
  2002年   22篇
  2001年   13篇
  2000年   18篇
  1999年   13篇
  1998年   9篇
  1997年   11篇
  1996年   4篇
  1995年   1篇
  1994年   9篇
  1993年   8篇
  1992年   6篇
  1991年   4篇
  1990年   3篇
  1989年   4篇
  1988年   2篇
  1987年   1篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1981年   2篇
  1980年   2篇
  1978年   1篇
  1977年   1篇
  1973年   2篇
  1972年   1篇
排序方式: 共有482条查询结果,搜索用时 15 毫秒
11.
目的探讨四黄散外敷治疗竹叶青蛇咬伤肿胀的临床疗效。方法选择2017年10月~2020年4月我院收治的112例竹叶青蛇咬伤肿胀患者为研究对象,采用随机数字表法将患者分为观察组和对照组,每组56例。对照组采用常规蛇咬伤处理方案,包括清创、引流、注射抗蛇毒血清及对症治疗等。观察组在对照组治疗基础上采用四黄散外敷治疗。观察比较两组患者的有效止痛时间、肿胀开始消退时间、肿胀完全消退时间,并对两组患者治疗7d时的临床疗效进行比较。结果观察组在有效止痛时间、肿胀开始消退时间、肿胀完全消退时间方面均显著低于对照组,两组比较差异具有统计学意义(均P<0.05)。两组治疗后的总体疗效比较,观察组的治愈率为89.3%(50/56),对照组的治愈率为69.6%(39/56),两组比较差异有统计学意义(P<0.05)。结论四黄散外敷治疗竹叶青蛇咬伤肿胀的疗效确切,能有效减轻患者的疼痛感,促进肿胀消退,减轻炎症反应,值得临床应用。  相似文献   
12.
胡庆峰  罗毅  雷卓异  翟崇宇  王琦  吴雪 《蛇志》2021,(1):10-12,16
目的探讨动物学、临床医学跨界研究成果联合运用于快速准确诊断不明蛇类咬伤中的作用及效果。方法通过回顾性分析1例不明蛇类咬伤患者的临床资料,从病史、动物学生活习性、咬痕鉴别、流行病学、临床表现、蛇类动物学分布6个方面进行剖析不明蛇类咬伤的诊断思路与方法。结果该例蛇伤患者的病史特征以及诊断与鉴别诊断:(1)病史特征符合银环蛇生活习性;(2)咬痕特征首先符合毒蛇咬痕,其次与银环蛇咬痕特征高度吻合;(3)蛇伤流行病学研究支持被咬地域存在银环蛇致伤病种;(4)临床表现首先符合毒蛇咬伤,其次与银环蛇/金环蛇咬伤临床表现高度吻合;(5)依据桂中毒蛇种类分布研究成果结合银环蛇咬痕特征确诊为银环蛇咬伤。结论将蛇类动物学、临床医学跨界研究成果联合运用于不明蛇类咬伤的快速准确诊断是一种切实有效的方法。  相似文献   
13.
A phosphodiesterase I (EC 3.1.4.1; PDE-I) was purified from Walterinnesia aegyptia venom by preparative native polyacrylamide gel electrophoresis (PAGE). A single protein band was observed in analytical native PAGE and sodium dodecyl sulfate (SDS)-PAGE. PDE-I was a single-chain glycoprotein with an estimated molecular mass of 158 kD (SDS-PAGE). The enzyme was free of 5′-nucleotidase and alkaline phosphatase activities. The optimum pH and temperature were 9.0 and 60°C, respectively. The energy of activation (Ea) was 96.4, the Vmax and Km were 1.14 µM/min/mg and 1.9 × 10?3 M, respectively, and the Kcat and Ksp were 7 s?1 and 60 M ?1 min?1 respectively. Cysteine was a noncompetitive inhibitor, with Ki = 6.2 × 10?3 M and an IC50 of 2.6 mM, whereas adenosine diphosphate was a competitive inhibitor, with Ki = 0.8 × 10?3 M and an IC50 of 8.3 mM. Glutathione, o-phenanthroline, zinc, and ethylenediamine tetraacetic acid (EDTA) inhibited PDE-I activity whereas Mg2+ slightly potentiated the activity. PDE-I hydrolyzed thymidine-5′-monophosphate p-nitrophenyl ester most readily, whereas cyclic 3′-5′-AMP was least susceptible to hydrolysis. PDE-I was not lethal to mice at a dose of 4.0 mg/kg, ip, but had an anticoagulant effect on human plasma. These findings indicate that W. aegyptia PDE-I shares various characteristics with this enzyme from other snake venoms.  相似文献   
14.
ABSTRACT

Background : Cobra bite is frequently reported across the Indian subcontinent and is associated with a high rate of death and morbidity. In eastern India (EI) Naja naja and Naja kaouthia are reported to be the two most abundant species of cobra.

Research design and methods : The venom proteome composition of N. naja (NnV) and N. kaouthia (NkV) from Burdwan districts of EI were compared by separation of venom proteins by 1D-SDS-PAGE followed by LC-MS/MS analysis of protein bands. The potency of commercial polyantivenom (PAV) was assessed by neutralization, ELISA, immuno-blot and venom-PAV immunoaffinity chromatography studies.

Results : Proteomic analysis identified 52 and 55 proteins for NnV and NkV, respectively, when searched against the Elapidae database. A small quantitative difference in venom composition between these two species of cobra was observed. PAVs exhibited poor cross-reactivity against low molecular mass toxins (<20 kDa) of both cobra venoms, which was substantiated by a meager neutralization of their phospholipase A2 activity. Phospholipase A2 and 3FTx, the two major classes of nonenzymatic and enzymatic proteins, respectively, were partially recognized by PAVs.

Conclusions : Efforts must be made to improve immunization protocols and supplement existing antivenoms with antibodies raised against the major toxins of these venoms.  相似文献   
15.
16.
17.
Summary

Five structural types of the adult ovary were distinguished in a parthenogenetic viviparous scorpion Liocheles australasiae based on the presence or absence of swollen ovarian diverticula (SD) containing embryos and/or empty ones (ED) as remnants of past pregnancies. These structural types seem to correspond to the following ovarian functional phases: the ovary (1) with SD and without ED corresponds to the first pregnancy; (2) without SD and with ED to after the first parturition; (3) with SD and ED to the second pregnancy; (4) without SD and with old and new ED to after the second parturition; and (5) with SD and old and new ED to the third pregnancy. Such correspondence indicates that a female can repeat pregnancies at least three times. Some possible cases in which the present structural types correspond to other functional phases were also discussed.  相似文献   
18.
Mangshan pitviper, Protobothrops mangshanensis(formerly Zhaoermia mangshanensis) is endemic to China. Unfortunately, due to the decreasing size of its wild populations, this snake has been listed as critically endangered. Research carried out on the Mangshan pitviper's population ecology and captive reproduction has revealed that the unique head patch patterns of different individuals may potentially be used as a noninvasive recognition biometric character. We collected head patch pattern images of 40 individuals of P. mangshanensis between 1994 and 2011. By comparing each pitviper's head patch pattern, we found that the head patch pattern of individual snakes was different and unique. Additionally, we observed and recorded the head patch pattern characters of four adults and five juveniles before and after ecdysis. Our findings confirmed that head patch patterns of Mangshan pitvipers are unique and stable, remaining unchanged after ecdysis. Thus, individuals can be quickly identified by examining the head patch pattern within a specific recognition area on the head. This method may be useful for noninvasive individual recognition in many other species that display color patch pattern variations, especially in studies of endangered species where the use of invasive marking techniques is undesirable.  相似文献   
19.
Getting precise locations of target tumors can help to ensure ablation of cancerous tissues and avoid unwanted destruction of healthy tissues in high-intensity focused ultrasound (HIFU) treatment system. Because of speckle noise and spurious boundaries in ultrasound images, traditional image segmentation methods are not suitable for achieving the precise locations of target tumors in HIFU ablation. In this paper, a multi-step directional generalized gradient vector flow snake model is introduced for target tumor segmentation. In the first step, the traditional generalized gradient vector flow (GGVF) snake is used to obtain an approximate contour of the tumor. According to the approximate contour, a new distance map is generated. Subsequently, a new directional edge map is created by calculating a scalar product of the gradients of the distance map and the initial image. In this process, the gradient directional information and the magnitude information of the distance map are used to attenuate unwanted edges and highlight the real edges in the new directional edge map. Finally, a refined GGVF field is derived from a diffusion operation of the gradient vectors of the directional edge map. The GGVF field is used to refine the tumor's contour, by directing the approximate contour to edges with the desired gradient directionality. Based on the newly developed snake model, the influences of the spurious boundaries and the speckle noise are significantly reduced in the ultrasound image segmentation. Experimental results indicate that this technique is greatly useful for target tumor segmentation in HIFU treatment system  相似文献   
20.
Decisions relating to the orientation of movement by animals and how this translates into movement patterns can occur at multiple spatial scales simultaneously, but this interaction is poorly understood for many groups of animals. Using the tracks left by moving snakes in their sandy habitat, we studied the movement paths of the African snake Bitis schneideri (Namaqua dwarf adder) for evidence of broad‐scale directional persistence and short‐range avoidance of exposure. Although snakes clearly displayed directional persistence, they preferentially moved to nearby shrubs, thereby minimizing exposure to solar and thermal radiation and/or predation. Thus, snakes made decisions relating to orientation at a minimum of two scales, the interaction of which resulted in snakes moving ≈17% (mean straightness index = 0.85) further than the simple broad‐scale straight‐line distance. We assert that the actual path chosen by moving snakes represents a trade‐off of various costs and risks that include risk of predation, exposure to the elements, time and energy expenditure. Our study highlights the need for cognizance of the possibility of the scale dependence of orientation and movement in studies of snake movement, and adds to a growing literature demonstrating previously unrecognized behavioural complexity in snakes.  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