全文获取类型
收费全文 | 25106篇 |
免费 | 1299篇 |
国内免费 | 10篇 |
专业分类
林业 | 878篇 |
农学 | 757篇 |
基础科学 | 154篇 |
3623篇 | |
综合类 | 3568篇 |
农作物 | 913篇 |
水产渔业 | 1354篇 |
畜牧兽医 | 13334篇 |
园艺 | 272篇 |
植物保护 | 1562篇 |
出版年
2019年 | 252篇 |
2018年 | 418篇 |
2017年 | 510篇 |
2016年 | 471篇 |
2015年 | 339篇 |
2014年 | 459篇 |
2013年 | 968篇 |
2012年 | 805篇 |
2011年 | 958篇 |
2010年 | 690篇 |
2009年 | 674篇 |
2008年 | 969篇 |
2007年 | 926篇 |
2006年 | 814篇 |
2005年 | 741篇 |
2004年 | 652篇 |
2003年 | 716篇 |
2002年 | 613篇 |
2001年 | 809篇 |
2000年 | 803篇 |
1999年 | 638篇 |
1998年 | 274篇 |
1997年 | 283篇 |
1995年 | 259篇 |
1994年 | 232篇 |
1993年 | 233篇 |
1992年 | 435篇 |
1991年 | 525篇 |
1990年 | 440篇 |
1989年 | 419篇 |
1988年 | 404篇 |
1987年 | 417篇 |
1986年 | 365篇 |
1985年 | 389篇 |
1984年 | 341篇 |
1983年 | 289篇 |
1982年 | 243篇 |
1979年 | 386篇 |
1978年 | 296篇 |
1977年 | 290篇 |
1976年 | 300篇 |
1975年 | 319篇 |
1974年 | 335篇 |
1973年 | 309篇 |
1972年 | 294篇 |
1971年 | 248篇 |
1969年 | 296篇 |
1968年 | 275篇 |
1967年 | 329篇 |
1966年 | 306篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
The literature mostly indicates that docking fat-tailed lambs initially reduces growth but that post-weaning growth and feed
conversion efficiency then increase. The amount of fat deposited, the total separable lean meat to fat ratio and the meat
quality all increase, while the percentage of bone in the carcase either decreases or does not change in the carcases of the
docked lambs. Wool growth and characteristics are, in general, not affected and reproductive traits in ewes and lambs are
improved by docking. The rectal temperature, respiration rate and pulse rate are decreased following docking. The concentrations
of immunoreactive beta-endorphin and cortisol in the plasma and the incidence of foot stamping and restlessness, as indicators
of stress, increase after docking. Other constituents of the blood are not significantly altered following docking or by the
methods of docking. Docking of fat-tailed sheep using rubber rings at one day of age can be recommended.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
83.
Klejbor I Luczyńska A Ludkiewicz B Domaradzka-Pytel B Moryś J 《Polish journal of veterinary sciences》2003,6(3):201-207
The thalamic nuclei with their defined set of input-output connections are the primary channel for information flow to the cerebral cortex. Several data suggest that neurons of that area are involved in the response to various aversive stimulations. However the pattern of activation seems to depend on the stress model as well as the stage of maturation. In the present study we would like to check which nuclei of the thalamus show expression of c-fos in the response to the "open field test", and how this response pattern changes during the maturation process. 30 rats of age ranged from P0 to P120 (P-postnatal day) were studied. The experimental group was exposed to the "open field test" for 10 minutes. After perfusion and fixation, brains were cut and stained for c-fos with immunohistochemical method. Our results showed that during development the pattern of c-fos activity in the thalamic nuclei after stress stimulation undergoes significant changes. Distinct c-fos expression was observed in the paraventricular nucleus, intergeniculate leaflet and ventral lateral geniculate nucleus. These findings suggest that these nuclei may play a direct role in the stress reaction involved in the response to the "open field test". 相似文献
84.
The department of National Parks and Protection of Wild Nature sent five (two males, three females) adult long-legged buzzards for investigation of their deaths to Ankara University Veterinary Faculty. Facial bones of buzzards were evaluated. Distinguishing facial features such as strong os premaxillare, cavum nasale filled with spider webbing-like structures, prominent os prefrontalis and processes, H-shaped paraglossum were determined. In this study, we investigated the anatomic properties of facial bones in long-legged buzzard. We also aimed to identify the data using these bones in order to separate different bird species. 相似文献
85.
86.
87.
Strains of the bacterium Ornithobacterium rhinotracheale (ORT), a causal agent of respiratory diseases in birds, were microbiologically isolated, identified, and molecularly characterized. Blood-enriched culture media and biochemistry tests were used for microbiologic identification. Polymerase chain reaction (PCR) and repetitive extragenic palindromic PCR (rep-PCR) techniques were used for molecular identification and characterization, respectively, of the microorganism. ORT strains were isolated in enriched media from the trachea and air sacs of broilers, breeders, and layers from several geographic zones of Peru. Of the original 75 strains isolated from 75 clinical samples from which ORT was recovered during 1998-2000, 25 were selected for further study based on ORT as the primary pathogenic isolate (no other pathogens were detected). Selected isolates were molecularly identified and characterized by PCR using specific primers designed from the conserved zones of the 16S ribosomal genes. Primers used for the identification of ORT produced a specific fragment of 784 base pair (bp), which did not appear in Haemophilus paragallinarum or Pasteurella multocida, microorganisms with similar morphologic and biochemical characteristics that produce dinical signs identical to those of ORT. All 25 strains of ORT tested with rep-PCR had a genetic profile similar to that of ORT American Type Culture Collection 51463, indicating the presence of only one genotype in the ORT strains studied. 相似文献
88.
Van de Maele I Rogier N Daminet S 《The Canadian veterinary journal. La revue veterinaire canadienne》2005,46(8):718-723
Home monitoring of blood glucose (HMBG) concentrations has been recommended in the monitoring of human diabetics for 3 decades. During the last number of years, it also gained popularity in long-term follow-up of diabetic cats and dogs. The aim of this retrospective study was to evaluate the practical feasibility of and identify the major problems encountered with HMBG in diabetic pets. A standard questionnaire was filled in by owners of 9 diabetic pets monitored with HMBG. The need for more than 1 puncture to obtain a blood drop, the creation of a sufficient blood drop, the need for assistance in restraining the pet, and the resistance of the pet were the most frequently encountered problems during HMBG. The major obstacles for the owners to start with HMBG were also identified. In conclusion, HMBG is a practical and simple technique for most owners and, overall, owners were satisfied. 相似文献
89.
Carrillo JM Sopena JJ Rubio M Redondo JI Serra I Soler C 《Veterinary surgery : VS》2005,34(4):387-392
OBJECTIVE: To evaluate the use of polyamide bands, manufactured for securing electrical cables, for repair of oblique femoral fractures in rabbits. STUDY DESIGN: Experimental study. ANIMALS: Twelve nulliparous, 21-25-week-old, California female rabbits. METHODS: Rabbits were divided into 3 groups (n=4) and studied for 14, 28, or 56 days. A Z-shaped mid-diaphyseal femoral osteotomy was repaired with a 2.5 mm intramedullary pin and a polyamide 6.6 cerclage band. Healing was evaluated at intervals by physical examination, limb use, femoral radiographs, and callus histology. RESULTS: Rabbits had early limb use with good wound healing. From the 1st day, movement of the hip and stifle joints was satisfactory. Radiographically, fractures were healed at 28 days. Histologically, there was no foreign body reaction and bone healing was normal. CONCLUSION: Nylon cerclage band application was accomplished easily, maintained reduction, and resulted in good healing and limb use. CLINICAL RELEVANCE: Sterilized nylon bands, manufactured for electrical use, can be used for cerclage in rabbits. 相似文献
90.
The arterial supply to the retina and lens of 10 fetal, 10 neonatal and four adult Zavot-bred cattle of both sexes was studied macroscopically and by stereoscopic microscopy by means of vascular perfusion with latex, giving special emphasis on the hyaloid artery. The central retinal artery ramified in four major retinal arterioles, which formed a compact network throughout the retina (holangiotic or euangiotic pattern). The hyaloid artery was patent in all fetal stages and extended through the vitreous cavity of the eye to the caudal surface of the capsule of the lens. Atrophy of the hyaloid artery began immediately after birth and was completed on day 17 after parturition. No remnant of the hyaloid artery in the vitreous cavity was observed in the adult cattle examined at stereoscopic microscopic level. 相似文献