全文获取类型
收费全文 | 3123篇 |
免费 | 149篇 |
国内免费 | 2篇 |
专业分类
林业 | 58篇 |
农学 | 112篇 |
基础科学 | 25篇 |
347篇 | |
综合类 | 411篇 |
农作物 | 122篇 |
水产渔业 | 160篇 |
畜牧兽医 | 1752篇 |
园艺 | 58篇 |
植物保护 | 229篇 |
出版年
2021年 | 30篇 |
2020年 | 38篇 |
2019年 | 36篇 |
2018年 | 42篇 |
2017年 | 46篇 |
2016年 | 46篇 |
2015年 | 39篇 |
2014年 | 48篇 |
2013年 | 162篇 |
2012年 | 103篇 |
2011年 | 99篇 |
2010年 | 60篇 |
2009年 | 66篇 |
2008年 | 122篇 |
2007年 | 110篇 |
2006年 | 106篇 |
2005年 | 105篇 |
2004年 | 82篇 |
2003年 | 94篇 |
2002年 | 111篇 |
2001年 | 112篇 |
2000年 | 98篇 |
1999年 | 64篇 |
1998年 | 39篇 |
1997年 | 33篇 |
1996年 | 40篇 |
1995年 | 43篇 |
1992年 | 41篇 |
1991年 | 63篇 |
1990年 | 64篇 |
1989年 | 53篇 |
1988年 | 54篇 |
1987年 | 59篇 |
1986年 | 61篇 |
1985年 | 57篇 |
1984年 | 52篇 |
1983年 | 50篇 |
1982年 | 36篇 |
1981年 | 30篇 |
1979年 | 31篇 |
1978年 | 33篇 |
1977年 | 37篇 |
1976年 | 31篇 |
1975年 | 29篇 |
1974年 | 36篇 |
1973年 | 35篇 |
1972年 | 35篇 |
1971年 | 33篇 |
1970年 | 34篇 |
1969年 | 26篇 |
排序方式: 共有3274条查询结果,搜索用时 62 毫秒
1.
2.
125I-labelling was used to characterise the surface components of five stocks of Trypanosoma evansi. Two components of 67 and 60.5 kD were labelled in two of the stocks, a single 60.5 kD component in two other stocks and no components in the remaining stock. These differences are probably related to the labelling method and biochemical differences between the stocks. 相似文献
3.
4.
DV COUSINS SN WILLIAMS R. REUTER† D. FORSHAW† B. CHADWICK§ D. COUGHRAN¶ P. COLLINS# N. GALES 《Australian veterinary journal》1993,70(3):92-97
SUMMARY Tuberculosis was diagnosed in 3 otariid seals found dead on beaches at 3 locations on the south coast of Western Australian between May 1990 and March 1991. This confirms that tuberculosis is present in the 2 native seals (Neophoca cinerea and Arctocephalus forsteri) in Western Australian waters. Mycobacterium sp isolated from the lungs of 2 of the seals were studied to determine the similarity of the strains to each other, to the strains isolated during 1986 from Australian sea lions and New Zealand fur seals kept in captivity at a marine park near Perth, Western Australia, and to a strain isolated in 1988 from a seal trainer who worked with the infected captive seals for 3 years. After restriction endonuclease analysis (REA) with the endonucleases Bst Ell, Bcl I and Pvu II, one of the wild seal strains appeared to have identical DNA fragment patterns to the strains from the captive seals and the seal trainer. The other wild seal isolate had identical REA profiles using Bst EII and Bcl I, but a minor difference was detected using Pvu II. Differences in these isolates were more clearly seen in restriction fragment length polymorphisms after hybridisation with two DNA probes. The secretory protein MPB70, present in M bovis, was not detected in wild seal isolates using sodium dodecyl sulphate polyacrylamide gel electrophoresis and Western blotting techniques. Analysis of protein and DNA fragment profiles indicated that seal tuberculosis isolates form a unique cluster within the M tuberculosis complex. 相似文献
5.
Response time of broiler chickens to cimaterol: meat tenderness, muscle composition fiber size, and carcass characteristics. 总被引:4,自引:0,他引:4
The response time to cimaterol (CIM), a beta-adrenergic agonist, by broiler chickens for carcass characteristics, muscle composition, muscle fiber size, catheptic enzyme activity, and tenderness was determined. Two trials were conducted in which chickens were fed a control diet (CON) containing 0 ppm of CIM or a diet containing 1 ppm of CIM. Trial 1 consisted of 55, 31-d-old broiler chickens individually fed for up to 48 h. At 0, 6, 12, 18, 24, and 48 h, five CON and five CIM-fed chickens were killed. Trial 2 consisted of 160, 33-d-old broiler chickens group-fed for up to 14 d. At 2, 4, 6, 8, 10, 12, and 14 d, 10 CON and 10 CIM-fed chickens were killed. The breast muscle (BM) and leg muscle (LM) weight, cathepsin B and L activities, DNA, RNA, and protein concentration, and BM shear force value (SFV) were measured in both trials. Thigh muscle (TM) SFV were measured in Trial 2 only. Fiber size of BM was measured (five birds per treatment) at d 2, 6, 10, and 14. In Trial 1, BM weight and SFV were lower in CIM-fed birds at 6 h (P less than .05). In Trial 2 BM SFV were higher at d 8 (P = .06) and d 10 (P less than .05) in CIM-fed chickens. The SFV of CIM-fed chickens were higher at d 4, 8, 10, 12, and 14 (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
6.
R. S. Jones 《The Journal of small animal practice》1992,33(9):423-429
There are a variety of factors which are likely to influence the action of muscle relaxants in canine anaesthesia. These include age, body temperature and muscle diseases. Of the anaesthetic agents it is only the inhalational anaesthetic agents which significantly increase the duration of action of muscle relaxants. Antibiotic therapy particularly with the aminoglycoside antibiotics is likely to increase their duration of action. The indications for the use of muscle relaxants and the main contraindications such as the absence of anaesthetic equipment and the inability to ensure unconsciousness are discussed. The choice of anaesthetic technique together with a discussion on the premedication induction and maintenance of anaesthesia are important factors when using relaxants as is the technique of artificial ventilation. The various advantages and disadvantages of neuromuscular block monitoring are discussed as is the reversal of neuromuscular block. 相似文献
7.
Characterization of Brucella canis protein antigens and polypeptide antibody responses of infected dogs 总被引:1,自引:0,他引:1
The cytoplasmic protein antigens (CPAg) of Brucella canis were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and analysis of 35S-labeled polypeptides. Approximate molecular weights of the immunoreactive polypeptides were determined by migration patterns of the immunoprecipitated polypeptides after SDS-PAGE or Western immunoblotting of sera collected at various times after experimental infection of dogs. Polypeptides were specifically precipitated by sera of infected dogs, but not from the sera of normal or false-positive (seropositive, non-infected) animals. During the initial month after infection, proteins with molecular weight masses (MW) of approximately 18, 22, 31, 42 and 54 kDa were commonly recognized. A 20-kDa polypeptide was first recognized at 8-10 weeks after infection, but it was detected inconsistently after 6 months. Additional polypeptides detected from 2 to 12 months post-infection had MW of 22, 66-68 and, less regularly, 42, 60, 82, 100 and greater than 200 kDa. The polypeptides most consistently recognized in sera from B. canis-infected dogs had MW of 18, 22 and 68 kDa. 相似文献
8.
L.E. Young D.H. Bartram M. Diamond A. Gregg R.S. Jones 《Veterinary anaesthesia and analgesia》1991,18(Z1):171-174
9.
10.