全文获取类型
收费全文 | 3435篇 |
免费 | 184篇 |
国内免费 | 1篇 |
专业分类
林业 | 126篇 |
农学 | 129篇 |
基础科学 | 8篇 |
581篇 | |
综合类 | 370篇 |
农作物 | 464篇 |
水产渔业 | 248篇 |
畜牧兽医 | 1493篇 |
园艺 | 40篇 |
植物保护 | 161篇 |
出版年
2022年 | 32篇 |
2021年 | 87篇 |
2020年 | 50篇 |
2019年 | 56篇 |
2018年 | 90篇 |
2017年 | 86篇 |
2016年 | 90篇 |
2015年 | 95篇 |
2014年 | 131篇 |
2013年 | 184篇 |
2012年 | 199篇 |
2011年 | 245篇 |
2010年 | 131篇 |
2009年 | 116篇 |
2008年 | 207篇 |
2007年 | 208篇 |
2006年 | 141篇 |
2005年 | 151篇 |
2004年 | 149篇 |
2003年 | 133篇 |
2002年 | 114篇 |
2001年 | 77篇 |
2000年 | 69篇 |
1999年 | 48篇 |
1998年 | 17篇 |
1997年 | 26篇 |
1996年 | 18篇 |
1994年 | 14篇 |
1993年 | 12篇 |
1992年 | 37篇 |
1991年 | 40篇 |
1990年 | 37篇 |
1989年 | 31篇 |
1988年 | 22篇 |
1987年 | 34篇 |
1986年 | 30篇 |
1985年 | 35篇 |
1984年 | 30篇 |
1983年 | 21篇 |
1979年 | 20篇 |
1978年 | 12篇 |
1977年 | 21篇 |
1976年 | 12篇 |
1974年 | 17篇 |
1973年 | 23篇 |
1972年 | 18篇 |
1971年 | 14篇 |
1970年 | 18篇 |
1969年 | 20篇 |
1968年 | 13篇 |
排序方式: 共有3620条查询结果,搜索用时 15 毫秒
951.
Jae Hoon Shin Je Kyung Seong Sun Shin Yi 《Journal of veterinary science (Suw?n-si, Korea)》2014,15(1):19-26
Type 1 diabetes is a common metabolic disorder accompanied by increased blood glucose levels along with glucocorticoid and cognitive deficits. The disease is also thought to be associated with environmental changes in brain and constantly induces oxidative stress in patients. Therefore, glucocorticoid-mediated negative feedback mechanisms involving the glucocorticoid receptor (GR) binding site are very important to understand the development of this disease. Many researchers have used streptozotocin (STZ)-treated diabetic animals to study changes in GR expression in the brain. However, few scientists have evaluated the hyperglycemic period following STZ exposure. In the present study, we found GR expression in the hippocampus varied based on the period after STZ administration for up to 4 weeks. We performed immunohistochemistry and Western blotting to validate the sequential alterations of GR expression in the hippocampus of STZ-treated type 1 diabetic rats. GR protein expression increased significantly until week 3 but decreased at week 4 following STZ administration. GR expression after 70 mg/kg STZ administration was highest at 3 weeks post-treatment and decreased thereafter. Although STZ-induced increase in GR expression in diabetic animals has been described, our data indicate that researchers should consider the sequential GR expression changes during the hyperglycemic period following STZ exposure. 相似文献
952.
Shin‐ichi Tagawa Ken‐ichi Horiguchi Norio Yoshida Toshiyoshi Takahashi 《Animal Science Journal》2014,85(7):787-791
A fermented total mixed ration (TMR) was prepared by adding a vitamin premix containing vitamin A and enzyme to reed canarygrass roughage. The vitamin A levels were then determined after 30 days of fermentation at 20 or 30°C. The vitamin A contents had decreased in roughage fermented at both storage temperatures, and decreased further when an enzyme supplement was included. Because the majority of the added vitamin A was destroyed during fermentation and storage, the addition of vitamin A at the beginning of preparation of fermented TMR is not recommended. 相似文献
953.
This study was aimed at investigating the long‐term effects of provision of liquid milk replacer (MR) and solid starter diet (SD) during lactation on post‐weaning (PW) growth of pigs. In experiment 1, 33 cross‐bred litters were allotted to four treatments: no supplement (CON), MR ad libitum, SD ad libitum and 100 g SD/litter/day from lactation day 4 through weaning at day 21 during late fall. In experiment 2, 40 litters received MR or none in July. PW pigs received commercial diets to marketing. In experiment 1, weaning weight (WW), pre‐weaning average daily gain (ADG) and mortality (2.4%) were not influenced by creep‐feeding MR or SD. ADG was greater (P < 0.05) in the MR group versus CON during days 21–54, but did not differ across the treatments during days 54–162. In experiment 2, ADG during lactation and WW were greater in the MR group versus CON, with mortality lower in the former (5.6 vs. 10.3%). However, PW ADG to day 175 did not differ between the two groups. Results suggest that creep‐feeding MR or SD has no effect on PW growth. However, it remains possible that MR reduces PW mortality during the hot season. 相似文献
954.
Applications of zeolite films benefit from alignment of the integrated channels, but methods for film growth have nearly always introduced orientational randomization in the direction normal to the substrate. We now report facile methods to grow silicalite-1 films and pure silica beta zeolite films on substrates with straight or sinusoidal channels positioned uniformly upright at a thickness of up to 8 micrometers. Precise gel compositions and processing temperatures are critical to promote secondary growth on pre-formed oriented crystal monolayers while suppressing self-crystallization in the bulk medium. Preliminary results highlight the potential of these uniformly oriented films in the nonlinear optical response and separation of xylene isomers. 相似文献
955.
956.
Australian Bat Lyssavirus (ABLV) is a fatal rabies‐like disease spread to humans from bats. All people who report bat bites or scratches in Queensland are considered potentially exposed to ABLV and are followed up and treated to prevent ABLV. Preventing members of the public intentionally interacting with bats will reduce the number of potential exposures to ABLV. In order to target public health messaging, this study examines the epidemiology of potential ABLV exposures in Metro North Hospital and Health Service (HHS), a region of Queensland that encompasses metro and rural areas in the south‐east of the state. People who intentionally handled bats during the study period were more likely to be adult (93%), male (60%), scratched (51%) by a megabat (72%) and been potentially exposed while rescuing the bat when it was trapped or injured (72%). The number of potential exposures reported in Queensland has increased since 2013; the same year, a Queensland child died of ABLV. Seasonally, exposures are more common during bat breeding and nursing periods when bats are more active (summer to autumn). Although there were more notifications in a band stretching north from the inner city to northern metro suburbs, notification rates were higher in large rural statistical areas in the north of the HHS. These data will be used to develop geographically targeted ABLV prevention messaging for the general public. 相似文献
957.
958.
Blood forms of human vivax malaria infected splenectomized night monkeys (Aotus trivirgatus). Anopheles albimanus mosquitoes transmitted the in fection from a monkey to two human volunteers; parasites and symptoms ap peared 11 days later. Blood forms of vivax malaria from each of the two humans infected other night monkeys. 相似文献
959.
The traditional view that quantal release of neurotransmitter results from the fusion of transmitter-containing vesicles with the neuronal membrane has been recently challenged. Although various alternative mechanisms have been proposed, a common element among them is the release of cytoplasmic transmitter, which, in one view, could occur through large conductance channels on the presynaptic membrane. Six nerve-muscle cell pairs were examined with a whole-cell patch clamp for the presence of such channels that are associated with the production of miniature end-plate potentials. Examination of the neuronal membrane current during the occurrence of 822 miniature end-plate potentials produced no evidence of large channels. Thus it is unlikely that quantal release is mediated by such channels in the neuromuscular junction. 相似文献
960.
1988~1989年,作者在开化、临安、龙泉3县试验点,采用8种除草剂,以不同剂量,混用或单用,对1~3年生杉木幼龄林作化学除草试验。结果表明:草甘膦+盖灌能除草除灌效果最好。化学除草与人工除草相比,每年可节约费用81.8~101.6元/hm~2. 相似文献