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   72篇
  免费   7篇
  国内免费   2篇
基础医学   12篇
临床医学   2篇
内科学   18篇
皮肤病学   1篇
特种医学   4篇
外科学   1篇
综合类   4篇
预防医学   35篇
药学   1篇
中国医学   3篇
  2023年   1篇
  2022年   4篇
  2021年   3篇
  2019年   3篇
  2018年   1篇
  2017年   2篇
  2016年   3篇
  2015年   6篇
  2014年   3篇
  2013年   1篇
  2012年   3篇
  2011年   5篇
  2010年   3篇
  2009年   2篇
  2008年   1篇
  2007年   3篇
  2006年   1篇
  2005年   1篇
  2004年   3篇
  2003年   2篇
  2002年   3篇
  2001年   4篇
  2000年   4篇
  1999年   2篇
  1998年   4篇
  1997年   1篇
  1996年   4篇
  1995年   2篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1986年   1篇
排序方式: 共有81条查询结果,搜索用时 15 毫秒
1.
中国野生獐资源保护与饲养   总被引:7,自引:0,他引:7  
关磊  苏铁 《中药材》2004,27(1):5-6
我国现存的四大野生獐种群不容乐观,它们的分布区已大为缩小并分割成块,栖息地遭到破坏,种群数量过少.因而保护应以栖息地为重点,人工饲养可以成为解决目前野生獐种群保护与利用之间平衡的一种有效手段.  相似文献   
2.
3.
[摘要] 目的 分析环境和气候因子对我国长角血蜱适生区分布的影响,并预测不同气候模式下长角血蜱的潜在分布区。方法 从文献中获取我国长角血蜱分布点信息,结合环境和气候因子数据,运用MaxEnt最大熵模型,分析年均温、昼夜温差日均值、等温性、温度季节性变化标准差、最暖月最高温、最冷月最低温、年均温变化范围、最湿季度平均温度、最干季度平均温度、最暖季度平均温度、最冷季度平均温度、年均降水量、最湿月降水量、最干月降水量、降水量变异系数、最湿季度降水量、最干季度降水量、最暖季度降水量、最冷季度降水量等19个气候因子及海拔、坡度、坡向、植被覆盖率等4个环境因子对长角血蜱潜在分布的影响,并预测当前和未来不同气候模式下(RCP 2.6和RCP 8.5)长角血蜱潜在地理分布区。结果 在影响我国长角血蜱地理分布的环境和气候因子中,贡献率均超过10%的因子主要包括最干月降水量(26.0%)、年均温(11.2%)、年均降水量(10.0%)和海拔(24.2%)。当前气候模式下,我国长角血蜱高、中、低适生区面积分别为123.19万、169.62万、185.44万km2。在RCP 2.6气候模式下,2050和2070年我国长角血蜱分布区面积分别增加33.61万km2和36.73万km2;在RCP 8.5气候模式下,2050年和2070年我国长角血蜱分布区面积分别增加38.10万km2 和35.80万km2。结论 降水、温度和海拔等气候和环境因子对我国长角血蜱分布区影响较大;在未来不同气候模式下,我国长角血蜱适生区面积均可能增加。  相似文献   
4.
Tick saliva plays a vital role in blood-feeding, including manipulation of the host response to tick infestation. Furthermore, a diverse number of tick-borne pathogens are transmitted to vertebrate hosts via tick saliva, some of which exploit the immunomodulatory activities of their vector's saliva. We report that salivary gland extracts (SGE) derived from Dermacentor reticulatus adult ticks induce a decrease in the natural killer (NK) activity of effector cells obtained from healthy human blood donors. The decrease was observed with SGE from both female and male D. reticulatus fed for either 3 or 5 days on mice, but no significant effect was observed with SGE from unfed ticks or ticks that had fed for 1 day. These results indicate that the tick anti-NK factor(s) is only active after blood-feeding has commenced. Microscopic examination revealed that the first step of NK activity, namely effector/target cell conjugate formation, was affected by SGE. The observed reduction in conjugate formation occurred when effector (but not target) cells were treated with SGE for 30 min, and the effect persisted after 12 h of treatment. Similar but less potent anti-NK activity was detected for SGE from Amblyomma variegatum and Haemaphysalis inermis. By contrast, SGE derived from Ixodes ricinus and Rhipicephalus appendiculatus female ticks did not decrease NK activity. The apparent absence of such activity in these two important vectors of tick-borne viruses suggests that control of NK cells does not play an important role in promoting virus transmission, at least for these particular species.  相似文献   
5.
用随机扩增多态DNA(RAPD)区分青海血蜱与日本血蜱   总被引:2,自引:0,他引:2  
目的用随机扩增多态DNA(RAPD)技术确定青海血蜱与日本血蜱的分类地位。方法分别提取青海血蜱与日本血蜱的DNA,确定聚合酶链反应(PCR)总体积、反应条件。选取8条不同的随机排列碱基顺序的多聚核苷酸单链为引物,进行RAPD—PCR扩增反应。将扩增产物制备成DNA图谱,比较青海血蜱与日本血蜱基因组DNA多态性,从DNA水平鉴定这2种蜱。结果2种蜱仅有少部分DNA条带相同,大部分条带不同。结论RAPD技术可准确地鉴别青海血蜱与日本血蜱这2种形态特征十分相似的蜱种。  相似文献   
6.
目的:检测台湾角血蜱携带莱姆病螺旋体情况。方法:直接荧光抗体法(DFA)和病原分离培养。结果:该蜱是粤东丰溪自然保护区优势蜱种,用采集的该蜱50只取中肠涂片,DFA检测8只为阳性,阳性率16%;从115只(23组)该蜱中分离出1株莱姆病螺旋体,命名为MD6。经单克隆抗体鉴定,结果与国内M7菌种反应相同。结论:从媒介蜱类分离出莱姆病螺旋体,在广东尚属首次,证实该地为莱姆病流行区  相似文献   
7.
The ethanol extract of Lawsonia inermis (200 mg/kg/day) was used to evaluate the wound healing activity on rats using excision, incision and dead space wound models. The animals were divided into three groups of six each in the excision model and two groups of six each in the incision model and dead space models. The topical application was made in the case of excision wound model, whereas, oral treatment was done with incision and dead space wound models. The following differences were noted in the group of experimental animals which were treated with an extract of L. inermis when compared with the control and reference standard animals: a high rate of wound contraction (p < 0.001), a decrease in the period of epithelialization (p < 0.001), high skin breaking strength (p < 0.001), a significant increase in the granulation tissue weight (p < 0.001) and hydroxyproline content (p < 0.05). The extract-treated animals showed 71% reduction in the wound area when compared with controls which was 58%. Histological studies of the tissue obtained on day 10 from the extract-treated group showed increased well organized bands of collagen, more fibroblasts and few inflammatory cells when compared with the controls which showed inflammatory cells, scanty collagen fibres and fibroblasts. Enhanced wound contraction, increased skin breaking strength, hydroxyproline and histological findings suggest the use of L. inermis in the management of wound healing.  相似文献   
8.
目的研究长角血蜱两性生殖株和孤雌生殖株幼蜱在不同温度下的发育零点和有效积温。方法将长角血蜱两性生殖株和孤雌生殖株饱血幼蜱置于不同温度的环境中,观察发育历期和积温,采用拟合模型方程求出两性株和孤雌株幼蜱发育的零点温度,计算幼蜱发育的有效积温。结果长角血蜱两性株和孤雌株的发育零点分别为14.89℃和14.95℃,平均积温分别为(265.08±99.37)日度和(306.90±176.24)日度,有效积温分别为(101.44±147.66)日度和(116.51±116.79)日度。结论长角血蜱饱血幼蜱的发育历期随温度升高而缩短,两性株比孤雌株发育快,研究结果可以作为长角血蜱生物学的基础理论参数之一。  相似文献   
9.
56 adult ticks D. marginatus and 38 adult ticks H. punctata were sampled by the flagging method, transferred to the laboratory, dissected and tested for infection with Lyme disease spirochetes. 3 (7.9%) of the adult H. punctata and 2 (3.57%) of the adult D. marginatus were infected with B. burgdorferi (Bb). This report also presents the case of a patient, who developed Lyme disease symptoms after he had been bitten by a D. marginatus tick. The clinical diagnosis was confirmed by serological testing and by a biopsy, taken from the patient's skin lesion. The skin biopsy was examined under an electron microscope and Bb was found in the sections of the deeper strata of the dermis in two structural forms: (a) cylindrical bodies (protoplasm cylinder) with circular ends covered with a three-layered membrane; (b) granules, situated among the collagenous fibres either closely adhered to them or covered with a membrane. The result of the study demonstrates that in single cases in some ecosystems, ticks D. marginatus might be implicated in Bb transmission to humans as secondary vectors.  相似文献   
10.
历经三年,分别在三个区试点进行了区域试验。试验结果表明,乌苏1号(104.1-2.4)无芒雀麦饲草产量高,丰产性能好且稳定,属丰产刈草型耐旱无性系组合,已具备无芒雀麦新品种的标准和条件,达到了育种目标,在各区试点推广种植是适宜的。  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