全文获取类型
收费全文 | 2129篇 |
免费 | 189篇 |
国内免费 | 2篇 |
专业分类
林业 | 74篇 |
农学 | 26篇 |
基础科学 | 33篇 |
254篇 | |
综合类 | 372篇 |
农作物 | 78篇 |
水产渔业 | 174篇 |
畜牧兽医 | 1214篇 |
园艺 | 31篇 |
植物保护 | 64篇 |
出版年
2023年 | 16篇 |
2022年 | 17篇 |
2021年 | 40篇 |
2020年 | 66篇 |
2019年 | 61篇 |
2018年 | 49篇 |
2017年 | 48篇 |
2016年 | 36篇 |
2015年 | 36篇 |
2014年 | 49篇 |
2013年 | 90篇 |
2012年 | 84篇 |
2011年 | 128篇 |
2010年 | 58篇 |
2009年 | 52篇 |
2008年 | 107篇 |
2007年 | 108篇 |
2006年 | 83篇 |
2005年 | 81篇 |
2004年 | 72篇 |
2003年 | 84篇 |
2002年 | 74篇 |
2001年 | 40篇 |
2000年 | 41篇 |
1999年 | 33篇 |
1998年 | 14篇 |
1995年 | 16篇 |
1993年 | 13篇 |
1992年 | 31篇 |
1991年 | 38篇 |
1990年 | 28篇 |
1989年 | 36篇 |
1988年 | 43篇 |
1987年 | 31篇 |
1986年 | 31篇 |
1985年 | 39篇 |
1984年 | 28篇 |
1983年 | 30篇 |
1982年 | 13篇 |
1979年 | 19篇 |
1978年 | 15篇 |
1976年 | 11篇 |
1975年 | 14篇 |
1974年 | 23篇 |
1973年 | 15篇 |
1972年 | 11篇 |
1971年 | 12篇 |
1970年 | 16篇 |
1968年 | 10篇 |
1967年 | 10篇 |
排序方式: 共有2320条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Michelle S Schulte Agnes E Rupley 《Veterinary Clinics of North America: Exotic Animal Practice》2004,7(2):315-50, vi-vii
Birds are becoming more popular as pets, and the need for veterinary professionals to learn more about these pets is crucial. This article introduces the veterinary staff to basic information required to provide high-quality care to avian patients. High-quality nutrition for a variety of species and ages is included in this article. The importance of proper husbandry and intellectual stimulation with toys is also discussed. Special emphasis is placed on instructions for clients when making appointments, as well as recognizing signs of illness for both clients and veterinary staff. Capture, restraint, and sample collection are an important part of this article, as well as medication administration, anesthesia, supportive care, preventive care and grooming. A variety of aspects concerning the care of the avian patient are covered for the benefit of the client and veterinary technician. 相似文献
5.
Charlie M. Culpepper III Peter J. Allen 《Journal of the World Aquaculture Society》2016,47(3):314-326
Extensive crappie, Pomoxis spp., culture has been practiced for decades, however, knowledge of crappie aquaculture methods is limited. The following review synthesizes existing research on crappie aquaculture and identifies knowledge gaps where further research is needed. Topics such as life history, tank culture, feeding, reproduction and spawning, larval rearing, transport and harvest, triploidy, hybridization, and out‐of‐season spawning were reviewed. The outcome is a better understanding of hindrances preventing crappie aquaculture development in the past, particularly tank culture and induced spawning techniques, and specific research objectives with potential to enhance recreational and commercial production. 相似文献
6.
Review of chromatographic methods for chloramphenicol residues in milk, eggs, and tissues from food-producing animals 总被引:7,自引:0,他引:7
E H Allen 《Journal of the Association of Official Analytical Chemists》1985,68(5):990-999
Although chloramphenicol is not approved for use in food-producing animals in the United States, this broad spectrum antibiotic has been widely used to treat diseases in such animals including the lactating dairy cow. Extremely low ophthalmologic doses of chloramphenicol are known to cause aplastic anemia in humans. The residues in meat, milk, and eggs intended for human consumption cause particular public health concern because the bone marrow aplasia is not dose dependent. Furthermore, chloramphenicol, a known inhibitor of protein synthesis, also retards erythropoiesis, a condition that is dose dependent and may cause allergic hypersensitivity reactions. This paper is a review of sensitive methods that use gas, liquid, thin layer, and simple column chromatography as both determinative and cleanup steps for detecting and quantitating chloramphenicol in edible animal tissues, milk, and eggs. 相似文献
7.
Harsha Galkanda‐Arachchige Luke A. Roy Sunni Dahl Jesse James Anita M. Kelly Donald Allen Davis 《Aquaculture Research》2020,51(8):3460-3471
The current study evaluates the efficacy of a low‐cost salt mixture (LCSM) to replace expensive reconstituted sea salt (RSS) in the salinity acclimation and nursery phase of Pacific white shrimp under laboratory and farm conditions. LCSM was formulated to yield sodium, potassium, calcium and magnesium concentrations closely comparable to that of diluted seawater. Laboratory‐based nursery trials were conducted at 2, 6 and 15 g/L salinities, incrementally replacing RSS with LCSM (25%, 50%, 75% and 100%) at four replicates per treatment. Thirty postlarvae were reared for 7 days in 24‐L aquaria during the 2 and 6 g/L trials, while the nursery trial for 15 g/L salinity was conducted for 21 days with 400 postlarvae stocked in 150‐L tanks. On‐farm evaluation of LCSM was carried out in two tank‐based systems installed on levees adjacent to shrimp production ponds. RSS was incrementally replaced with LCSM (0%, 50%, 75% and 100%) and 100 postlarvae stocked into each 800‐L tank. Salinity acclimation was done from 30 g/L to 6 or 1.5 g/L within 2–3 days by pumping water from adjacent shrimp production ponds. Following salinity acclimation, the S4 system maintained flow‐through at 1.5 g/L, while N10 system was maintained static at 6 g/L salinity. At the conclusion, no significant differences were observed for either survival or growth of shrimp postlarvae between RSS and LCSM treatments at all salinities examined. Results reflect the potential use of LCSM to replace RSS, which could be an excellent solution to bring down the cost of production in inland shrimp aquaculture. 相似文献
8.
Olivier M Aggarwal A Allen J Almendras AA Bajorek ES Beasley EM Brady SD Bushard JM Bustos VI Chu A Chung TR De Witte A Denys ME Dominguez R Fang NY Foster BD Freudenberg RW Hadley D Hamilton LR Jeffrey TJ Kelly L Lazzeroni L Levy MR Lewis SC Liu X Lopez FJ Louie B Marquis JP Martinez RA Matsuura MK Misherghi NS Norton JA Olshen A Perkins SM Perou AJ Piercy C Piercy M Qin F Reif T Sheppard K Shokoohi V Smick GA Sun WL Stewart EA Fernando J Tejeda Tran NM Trejo T Vo NT Yan SC Zierten DL Zhao S 《Science (New York, N.Y.)》2001,291(5507):1298-1302
We have constructed a physical map of the human genome by using a panel of 90 whole-genome radiation hybrids (the TNG panel) in conjunction with 40,322 sequence-tagged sites (STSs) derived from random genomic sequences as well as expressed sequences. Of 36,678 STSs on the TNG radiation hybrid map, only 3604 (9.8%) were absent from the unassembled draft sequence of the human genome. Of 20,030 STSs ordered on the TNG map as well as the assembled human genome draft sequence and the Celera assembled human genome sequence, 36% of the STSs had a discrepant order between the working draft sequence and the Celera sequence. The TNG map order was identical to one of the two sequence orders in 60% of these discrepant cases. 相似文献
9.
Allen GJ Chu SP Schumacher K Shimazaki CT Vafeados D Kemper A Hawke SD Tallman G Tsien RY Harper JF Chory J Schroeder JI 《Science (New York, N.Y.)》2000,289(5488):2338-2342
Cytosolic calcium oscillations control signaling in animal cells, whereas in plants their importance remains largely unknown. In wild-type Arabidopsis guard cells abscisic acid, oxidative stress, cold, and external calcium elicited cytosolic calcium oscillations of differing amplitudes and frequencies and induced stomatal closure. In guard cells of the V-ATPase mutant det3, external calcium and oxidative stress elicited prolonged calcium increases, which did not oscillate, and stomatal closure was abolished. Conversely, cold and abscisic acid elicited calcium oscillations in det3, and stomatal closure occurred normally. Moreover, in det3 guard cells, experimentally imposing external calcium-induced oscillations rescued stomatal closure. These data provide genetic evidence that stimulus-specific calcium oscillations are necessary for stomatal closure. 相似文献
10.
Results show that PuO(2+x), a high-composition (x = 0.27) phase containing Pu(VI), is the stable binary oxide in air. This nonstoichiometric oxide forms by reaction of dioxide with water and by water-catalyzed reaction of dioxide with oxygen. The PuO(2) + H(2)O reaction rate is 0.27 nanomoles per meter squared per hour at 25 degrees C; the activation energy at 25 degrees to 350 degrees C is 39 kilojoules per mole. Slow kinetics and a low lattice parameter-composition dependence for fluorite-related PuO(2+x) are consistent with a failure to observe the phase in earlier studies. Perplexing aspects of plutonium oxide chemistry can now be explained. 相似文献