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   137篇
  免费   5篇
林业   15篇
农学   3篇
  29篇
综合类   5篇
农作物   15篇
水产渔业   24篇
畜牧兽医   46篇
园艺   1篇
植物保护   4篇
  2022年   2篇
  2021年   8篇
  2020年   6篇
  2019年   8篇
  2018年   8篇
  2017年   4篇
  2016年   9篇
  2015年   4篇
  2014年   4篇
  2013年   14篇
  2012年   7篇
  2011年   13篇
  2010年   5篇
  2009年   6篇
  2008年   8篇
  2007年   7篇
  2006年   1篇
  2005年   3篇
  2004年   3篇
  2003年   2篇
  2002年   1篇
  2000年   3篇
  1999年   4篇
  1998年   2篇
  1997年   1篇
  1995年   1篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1968年   1篇
  1967年   2篇
  1966年   1篇
  1965年   1篇
排序方式: 共有142条查询结果,搜索用时 15 毫秒
31.
This study was carried out to evaluate the healing potential of water-soluble extract of Plantago lanceolata as a topical ointment on experimental tendinitis in burros. Tendinitis was induced by injection of 2,500 U of bacterial collagenase in the superficial digital flexor tendon of both forelimbs of six male burros. Tendinitis was confirmed ultrasonographically. 48 hours after collagenase injection, two grams of 10% P lanceolata ointment was applied on one limb (treatment group) and the same amount of eucerin (the vehicle of the ointment) on the other limb (control group), every other day for 6 weeks. Ultrasonographic examination of the tendon was performed weekly during the study and mean cross-sectional area of the superficial digital flexor tendon was measured, which was found to increase significantly after injection of collagenase in both groups. From the third week, it decreased significantly in the treatment group in comparison with the control group. At the end of the study, the animals were euthanized for histopathological study of the tendons. In control group, degenerative changes in tendon could be seen, whereas significant degree of healing was observed in the treatment group. It can thus be concluded that the P lanceolata ointment was effective in promoting the healing process of the tendon.  相似文献   
32.
The aim of this study was to identify genomic regions associated with 305-day milk yield and lactation curve parameters on primiparous (n = 9,910) and multiparous (n = 11,158) Holstein cows. The SNP solutions were estimated using a weighted single-step genomic BLUP approach and imputed high-density panel (777k) genotypes. The proportion of genetic variance explained by windows of 50 consecutive SNP (with an average of 165 Kb) was calculated, and regions that accounted for more than 0.50% of the variance were used to search for candidate genes. Estimated heritabilities were 0.37, 0.34, 0.17, 0.12, 0.30 and 0.19, respectively, for 305-day milk yield, peak yield, peak time, ramp, scale and decay for primiparous cows. Genetic correlations of 305-day milk yield with peak yield, peak time, ramp, scale and decay in primiparous cows were 0.99, 0.63, 0.20, 0.97 and −0.52, respectively. The results identified three windows on BTA14 associated with 305-day milk yield and the parameters of lactation curve in primi- and multiparous cows. Previously proposed candidate genes for milk yield supported by this work include GRINA, CYHR1, FOXH1, TONSL, PPP1R16A, ARHGAP39, MAF1, OPLAH and MROH1, whereas newly identified candidate genes are MIR2308, ZNF7, ZNF34, SLURP1, MAFA and KIFC2 (BTA14). The protein lipidation biological process term, which plays a key role in controlling protein localization and function, was identified as the most important term enriched by the identified genes.  相似文献   
33.
Supplements produced by mouse testicular cells (mTCs) and the interaction between cells can increase the differentiation rate of human umbilical cord mesenchymal stem cells (hUCMSCs) into the germ-like cells. We studied the differentiation rate of hUCMSCs into the germ-like cells under effect of mTCs co-culturing. Isolated hUCMSCs from postpartum human umbilical cords were cultured. Then, the expression of mesenchymal (CD73, CD90 and CD105) and haematopoietic (CD34 and CD45) markers of hUCMSCs were confirmed by flow cytometry. Then, the hUCMSCs were cultured in four distinct groups: (a) control, (b) co-culture until D0, (c) co-culture until D5 and (d) co-culture until D10, in order to differentiate into the germ-like cells. After 10 days, the expression of OCT4, VASA, Fragilis and SYCP3 genes were examined by Real-Time qPCR. The flow cytometry indicated a high expression of mesenchymal markers and a low expression of haematopoietic markers (CD73:98.6%, CD90: 99.1%, CD105: 99.5%, CD34: 4.22% and CD45: 2.54%). The expression of OCT4 decreased during the time while the expression of VASA, Fragilis and SYCP3 markers increased in the co-culture with testicular cells (p value <.05). Co-culture with mTCs may be used as an effective method to differentiate hUCMSCs into germ-like cells.  相似文献   
34.
The irrigation return-flow coefficient (IRFC) is based on rule of thumb estimations in most aquifers in Iran. The errors may be significant, and thus misleading for water resources management. We used lysimeters to more accurately predict IRFC. Five wheat and barley farms of different soil textures, which were irrigated using a border system, plus one with a sprinkler system, were selected for the installation of lysimeters. The practices at each farm were applied to the lysimeters. Irrigation return flows (IRF) were measured every other day over two growing seasons. The IRF time series displayed sharp peaks at the initial stages of the growing season and decreasing towards the end. IRFCs were classified into early and late stages. The average IRFC during the early stage was 29.9%, decreasing to 6.5% in the late stage. High IRFC values are due to the limitations of border irrigation to provide a small uniform amount of water, and over-irrigation due to low water demand during the early stage of growth. Variations in annual IRFCs of 0.4 to 38.7% are functions of total applied water, border length, management and soil texture. The early stage IRFC for the sprinkler system was small. Therefore, high early stage IRFCs can be reduced by changing from border irrigation to a sprinkler system.  相似文献   
35.
Most of plant growth regulators are known to alleviate negative effects of osmotic stress on crop growth. To evaluate the effects of cycocel (CCC), as a growth regulator, on crop seed germination, early growth, and vegetative growth under osmotic stress conditions, a study was conducted under controlled conditions. Six crops, wheat, barley, maize, sunflower, safflower, and rapeseed were grown under five osmotic potentials (0, as non-stress, ?0.5, ?1.0, ?1.5, and ?2.0 MPa), which were raised from seeds treated with three CCC concentrations (0, 2.5, and 3.5 g l?1). Reduced germination, seedling and vegetative growth as well as enhanced leaf free proline and chlorophyll content index were observed under osmotic stress. The extent of these changes depended on the type of the used crops. Priming with optimum CCC concentration mitigated to great extent stress-induced adverse effects on these crops. The positive effect of CCC priming on wheat, maize, and rapeseed was observed only at moderate osmotic levels, whereas on barley and safflower the priming effects were found in all levels of osmotic stress. However, sunflower did not respond to CCC priming treatments which might have been due to its thick achene coat. CCC priming was found to be effective in diverting a major proportion of assimilates to root, because root to shoot dry weight ratio increased due to CCC application under all osmotic stress regimes. Since barley and safflower were found to be most responsive to CCC priming, further research for better understanding of mechanisms of CCC priming on their germination and vegetative growth is recommended.  相似文献   
36.
Post cesarean (CS) pain is a challenging problem for the obstetricians, because it may interfere with mother and baby's well-being. Many approaches have been ever proposed to diminish this pain, each one with particular benefits and limitations. Aromatherapy is a complementary therapy especially for controlling pain. This study aimed at evaluating the effect of lavender essence on post CS pain. In a single-blind clinical trial, 200 term pregnant women with planned elective CS were recruited in a 12 month period of time. They were randomized in two 100-patient groups; received either lavender essence (the case group) or a similar clinically neutral aromatic material (the control group) thorough oxygen mask for 3 min 3 h after receiving similar intravenous analgesics. The Visual Analogue Scale (VAS) was employed to determine the level of post CS pain. The VAS was documented half hour after first intervention. Eight and 16 h later, the aromatherapy was repeated and half hour after each intervention, corresponding VAS was documented. The two groups were matched for demographics and obstetrical history. The baseline VAS was comparable between the two groups. The mean VAS decreased significantly by 16 h after the first intervention in both groups (p < 0.001). However, this amelioration of pain was significantly more prominent in the cases group comparing with that in the controls in all documented stages half hour, 8 and 16 h after the first intervention (p < 0.001 for all measurements). In conclusion, aromatherapy by using lavender essence is a successful and safe complementary therapy in reducing pain after CS.  相似文献   
37.
The aim of this study was to evaluate the effects of different doses of dietary soy meals (with or without isoflavone) on dementia in ovariectomized (OVX) animal model of Alzheimer's disease. Female Wistar's rats with the exception of intact group were ovariectomized at the first line of study. Animals were divided into 2 main groups: control (c) and pre-treatment groups. Animals in pre-treatment groups received one of five types of diet during four weeks prior Nucleus Basalis Magnocellularis (NBM) electrical lesion normal diet (0), 10 g soy with isoflavone (10), 20 g soy with isoflavone (20), 10 g soy without isoflavone (-10) and 20 g soy without isoflavone (-20) in 30 g daily diet. The spatial learning and memory were tested using Morris water maze after electrical lesion. Rats were trained in water maze to find a hidden escape Platform. Rats received 6 blocks that each block consisted of 3 trials. Following acquisition trials, one probe trial was conducted in which the platform was removed. Soy meal diet (with or without isoflavone) in ovariectomized rats with Alzheimer's disease caused improvement of performance across 18 trials of Acquisition. Our results suggest that soy meal is a potential alternative to estrogen in the prevention and treatment of Alzheimer's disease.  相似文献   
38.
New phenantrene alkaloids from Cryptocarya crassinervia   总被引:1,自引:0,他引:1  
The bark of Cryptocarya crassinervia provided two new phenantrene alkaloids, 2-hydroxyatherosperminine (1) and N-demethyl-2-methoxyatherosperminine (2).  相似文献   
39.
40.
The present study was conducted to investigate the effects of the activator factor of the WNT pathway, chir98014, leading to the in vitro sheep oocyte maturation medium, on the cumulus cell development, different nuclear maturation stages and the following process of embryonic development. Experiments included (a) addition of different concentrations (0, 0.1, 0.5, 1 µm) of chir98014 to the maturation medium and evaluation of the cumulus cell expansion, (b) addition of different concentrations of chir98014 to the maturation medium and investigation of different nuclear maturation stages, (c) addition of different concentrations of chir98014 to the maturation medium and examination of the subsequent embryonic maturation process and (d) addition of different concentrations of chir98014 to the embryonic development culture medium (the first 48 hr) and investigation of the subsequent embryonic development process. The extracted data were analysed using the SPSS software, considering the significance level of p < .05 and making the mean comparisons. The results showed that the addition of the 0.1 µM concentration of chir98014 to the maturation medium had no significant effects on the oocyte maturation and embryo development post-fertilization but it enhanced the Cumulus-oocyte complexes (COCs) expansion. In the fourth experiment, the low concentration of chir98014 in the embryo culture media improved the embryo development process, whereas the high one had a detrimental effect on it, as compared to the control group. Thus, the presence of the lower concentrations of this compound in the embryonic culture medium had favourable effects on the development of embryos.  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