全文获取类型
收费全文 | 1757篇 |
免费 | 117篇 |
专业分类
林业 | 102篇 |
农学 | 32篇 |
基础科学 | 11篇 |
266篇 | |
综合类 | 361篇 |
农作物 | 72篇 |
水产渔业 | 114篇 |
畜牧兽医 | 812篇 |
园艺 | 36篇 |
植物保护 | 68篇 |
出版年
2023年 | 16篇 |
2022年 | 29篇 |
2021年 | 44篇 |
2020年 | 51篇 |
2019年 | 56篇 |
2018年 | 41篇 |
2017年 | 37篇 |
2016年 | 52篇 |
2015年 | 27篇 |
2014年 | 50篇 |
2013年 | 71篇 |
2012年 | 106篇 |
2011年 | 126篇 |
2010年 | 71篇 |
2009年 | 53篇 |
2008年 | 115篇 |
2007年 | 92篇 |
2006年 | 99篇 |
2005年 | 72篇 |
2004年 | 59篇 |
2003年 | 73篇 |
2002年 | 71篇 |
2001年 | 19篇 |
2000年 | 13篇 |
1999年 | 18篇 |
1996年 | 13篇 |
1995年 | 9篇 |
1994年 | 11篇 |
1993年 | 8篇 |
1992年 | 15篇 |
1991年 | 13篇 |
1990年 | 11篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 11篇 |
1986年 | 19篇 |
1985年 | 15篇 |
1984年 | 10篇 |
1983年 | 9篇 |
1979年 | 11篇 |
1978年 | 12篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 10篇 |
1974年 | 10篇 |
1973年 | 12篇 |
1971年 | 13篇 |
1969年 | 12篇 |
1968年 | 7篇 |
1967年 | 13篇 |
排序方式: 共有1874条查询结果,搜索用时 0 毫秒
61.
Results of a Preliminary Trial with Sphaerophorus necrophorus Toxoids to Control Liver Abscesses in Feedlot Cattle 总被引:1,自引:1,他引:0 下载免费PDF全文
M. M. Garcia D.C. Alexander K. A. McKay W. J. Dorward S. E. Magwood 《Canadian journal of veterinary research》1974,38(3):222-226
A preliminary field experiment was undertaken to evaluate the efficacy of alum precipitated toxoids of Sphaerophorus necrophorus prepared from sonicated whole cells and cell fractions to reduce the incidence of bovine abscesses. A total of 108 calves were divided into five groups and treated as follows: I. uninoculated control, II. adjuvant inoculated control, III. 15.5 mg protein of sonicated (fragmented cells) toxoid, IV. 10.5 mg protein of cytoplasmic toxoid. V. 15.5 mg protein of cytoplasmic toxoid. All animals were maintained under similar conditions to those prevailing in feedlots in Alberta. Livers were examined at slaughter. The most promising result was achieved with the injection of 15.5 mg protein of cytoplasmic toxoid. In this treatment group, no scars (healed lesions) were found in the liver and the incidence of liver abscesses was reduced to 10% from the average 35% liver abscesses and scars found in the uninoculated and adjuvant inoculated groups. The toxoid from sonicated whole cells did not reduce liver abscess incidence. These data suggest that the incidence of liver abscesses in cattle fattened in feedlots may be reduced by immunization. 相似文献
62.
A bacteriological survey of meat pies, frozen prepared dinners and entrees indicated that their bacterial populations were related to the components, the environment and handling in manufacture. Results were correlated with microbiological examinations of ingredients, line samples and plant environmental samples. Total bacterial counts, coliform counts and Staphylococcus counts of the finished product were low. Coliform organisms found were primarily Aerobacter spp. originating with the frozen vegetables. Enterococci were also found in the frozen vegetables and finished product. Both enterococci and Aerobacter organisms were recovered from the plant environment where they appeared to multiply. Many of the plant personnel carried coagulase-positive staphylococci in the throat or nasal cavity, and this was indicated as a possible source for these organisms found in low numbers in the finished product. Cooking of the products produced sterility except for the survival of some spore forming Bacillus spp. The presence of a poultry slaughtering operation adjacent to the manufacturing area was considered to contribute to microbial contamination of the air in the plant. 相似文献
63.
Discrimination of three trachurus species using both mitochondrial- and nuclear-based DNA approaches
Karaiskou N Triantafyllidis A Triantaphyllidis C 《Journal of agricultural and food chemistry》2003,51(17):4935-4940
A double-DNA approach was developed to discriminate the three Trachurus species that abide in European waters: T. trachurus, T. mediterraneus, and T. picturatus. The analysis aimed at both mitochondrial and nuclear loci. Polymerase Chain Reaction (PCR) amplification of the cytochrome b gene of mtDNA was followed by restriction analysis with three species-specific enzymes: NlaIII, NciI, and BsmAI. Digestion with these endonucleases yielded species-specific electrophoretic profiles. The universality of the results was verified by screening a large number of individuals from 12 geographical regions covering most of the distribution of the species. Additionally, the nuclear multicopy 5S rRNA gene was selected as an alternative candidate for the discrimination of the three Trachurusspecies. A simple agarose gel electrophoretic analysis of the amplicons proved to be capable of leading to unambiguous identification of the three Trachurus species. Thus, the double-DNA methodology presented here allows the accurate discrimination of Trachurus fish species and the detection of commercial fraud. 相似文献
64.
Werner AH 《Journal of the American Veterinary Medical Association》2003,223(7):1013-6, 986
Cyclosporine has been reported to be effective for the treatment of various cutaneous autoimmune disorders in dogs. Adverse reactions have generally been limited to gastrointestinal tract disturbances and cutaneous eruptions. The article describes antimicrobial-responsive cutaneous reactions in 3 dogs being treated with microemulsified cyclosporine A because of various dermatologic conditions. Cutaneous reactions in these dogs were similar to psoriasiform-lichenoid dermatitis and may represent an atypical staphylococcal infection. 相似文献
65.
66.
Biondo AW Liu ZL Wiedmeyer CE de Morais HS Sisson DD Solter PE 《American journal of veterinary research》2002,63(2):236-240
OBJECTIVE: To determine the nucleotide and amino acid sequence of atrial natriuretic peptide (ANP) in cats and its typical regions of cardiac expression. ANIMALS: 5 healthy adult mixed-breed cats. PROCEDURE: Total RNA was extracted from samples obtained from the left and right atrium, left and right ventricle, and interventricular septum of each cat. The RNA was used to produce cDNA for sequencing and northern blot analysis. Genomic DNA was extracted from feline blood samples. Polymerase chain reaction primers designed from consensus sequences of other species were used to clone and sequence the feline ANP gene. RESULTS: The feline ANP gene consists of 1,072 nucleotides. It consists of 3 exons (123, 327, and 12 nucleotides) separated by 2 introns (101 and 509 nucleotides). It has several typical features of eukaryotic genes and a putative steroid-response element located within the second intron. Preprohormone ANP consists of 153 amino acids. The amino acid sequence of the active form of feline ANP (ANP-30) is identical to that of equine, bovine, and ovine ANP-30 and differs from that of human, canine, and porcine ANP-28 only by 2 carboxy-terminal arginine residues. The ANP mRNA was detected only in the left and right atria. CONCLUSIONS AND CLINICAL RELEVANCE: The genetic and protein structure and principal regions of cardiac expression of feline ANP are similar to those of other species. Results of this study should be helpful in future studies on the natriuretic response in cats to diseases that affect cardiovascular function. 相似文献
67.
68.
69.
70.
Hoenig M Alexander S Holson J Ferguson DC 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2002,16(5):529-532
Intravenous glucose tolerance tests (IVGTTs) are used in cats and other species to assess insulin sensitivity. Several dosages have been reported but the dosage that maximally stimulates insulin secretion in cats has not been determined nor has it been compared in lean and obese animals. IVGTTs were performed in 4 lean and 4 obese spayed female cats with 5 glucose dosages: 0.3 (A), 0.5 (B), 0.8 (C), 1.0 (D). and 1.3 (E) g/kg body weight (BW). Each cat received each dosage in a random design. The glucose disposal rate was significantly different only between lean and obese cats at the highest glucose dosage. The area under the curve for insulin increased significantly among A, B, C, and D in lean and among A, B, and C in obese cats but not between D and E in lean and among C, D, and E in obese cats. Baseline insulin secretion was significantly higher (P = .03) and 1st peak insulin secretion was approximately 50% lower in obese as compared to lean cats (P = .03). Lean but not obese cats reached baseline insulin concentrations at all dosages at 120 minutes. We conclude that the glucose dosage for maximal insulin secretion is 1.0 g/ kg BW in lean and 0.8 g/kg BW in obese cats, supporting routine use of 1 g/kg BW to maximally stimulate insulin secretion regardless of body composition. Obese cats showed an abnormal insulin secretion pattern, indicating a defect in insulin secretion with obesity and insulin resistance. 相似文献