全文获取类型
收费全文 | 1587篇 |
免费 | 145篇 |
国内免费 | 2篇 |
专业分类
林业 | 71篇 |
农学 | 28篇 |
基础科学 | 16篇 |
263篇 | |
综合类 | 266篇 |
农作物 | 51篇 |
水产渔业 | 88篇 |
畜牧兽医 | 768篇 |
园艺 | 40篇 |
植物保护 | 143篇 |
出版年
2023年 | 9篇 |
2022年 | 7篇 |
2021年 | 16篇 |
2020年 | 34篇 |
2019年 | 26篇 |
2018年 | 22篇 |
2017年 | 29篇 |
2016年 | 28篇 |
2015年 | 28篇 |
2014年 | 31篇 |
2013年 | 74篇 |
2012年 | 82篇 |
2011年 | 107篇 |
2010年 | 72篇 |
2009年 | 41篇 |
2008年 | 107篇 |
2007年 | 113篇 |
2006年 | 102篇 |
2005年 | 101篇 |
2004年 | 90篇 |
2003年 | 82篇 |
2002年 | 111篇 |
2001年 | 34篇 |
2000年 | 36篇 |
1999年 | 25篇 |
1998年 | 26篇 |
1997年 | 19篇 |
1996年 | 24篇 |
1995年 | 11篇 |
1994年 | 18篇 |
1993年 | 21篇 |
1992年 | 20篇 |
1991年 | 10篇 |
1990年 | 15篇 |
1989年 | 18篇 |
1988年 | 4篇 |
1987年 | 15篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1974年 | 5篇 |
1972年 | 5篇 |
1968年 | 4篇 |
1962年 | 3篇 |
排序方式: 共有1734条查询结果,搜索用时 140 毫秒
1.
The immunohistochemical detection of Mycoplasma bovis and bovine viral diarrhea virus in tissues of feedlot cattle with chronic, unresponsive respiratory disease and/or arthritis. 下载免费PDF全文
D M Haines K M Martin E G Clark G K Jim E D Janzen 《The Canadian veterinary journal. La revue veterinaire canadienne》2001,42(11):857-860
The purpose of this study was to determine the frequency of selected pathogens in the tissues of a group of feedlot cattle with chronic disease (most often respiratory disease and/or arthritis). Samples of lung and joint tissues from 49 feedlot animals that had failed to respond to antibiotic therapy were tested by immunohistochemical staining for the antigens of Mycoplasma bovis, Haemophilus somnus, Pasteurella (Mannheimia) hemolytica, and bovine viral diarrhea virus (BVDV). Mycoplasma bovis was demonstrated in over 80% of cases, including in 45% of joints and 71% of lungs tested. Mycoplasma bovis was the only bacterial pathogen identified in the joints. Haemophilus somnus and Pasteurella (Mannheimia) haemolytica were found in 14% and 23% of cases, respectively, and were confined to the lungs in all instances. Infection with BVDV was demonstrated in over 40% of cases. Mycoplasma bovis and BVDV were the most common pathogens persisting in the tissues of these animals that had failed to respond to antibiotic therapy. 相似文献
2.
Edwin H. Robinson Menghe H. Li Bruce B. Manning 《Journal of the World Aquaculture Society》2001,32(1):68-71
Abstract.— This study was conducted to evaluate corn gluten feed as an alternative feedstuff in the diet of pond-raised channel catfish Ictalurus punctatus . Three 32%-protein diets containing 0%, 25%, or 50% corn gluten feed were tested. Channel catfish fingerlings (average weight: 57 g/fish) were stocked into 15 0.04-ha ponds at a rate of 18,530 fish/ha. Five ponds were used for each dietary treatment. Fish were fed to satiation once daily for a 147-d growing period. No differences were observed in feed consumption, weight gain, feed conversion ratio, survival, or fillet protein concentration among fish fed the test diets. Fish fed diets containing 25% and 50% corn gluten feed exhibited a lower level of visceral fat and a higher carcass yield than fish fed the control diet without corn gluten feed. The diet containing 50% corn gluten feed resulted in a lower level of fillet fat and a higher level of moisture than the control diet. There were no visible differences in the coloration of skin or fillet of channel catfish fed diets with and without corn gluten feed. Results from this study indicated that channel catfish can efficiently utilize corn gluten feed at levels up to 50%n without adverse effect on feed palatability, weight gain, or feed efficiency. Corn gluten feed may be beneficial in reducing fattiness of channel catfish and improving carcass yield by reducing the digestible energy to protein ratio of the diet. 相似文献
3.
Feline leukemia virus detection by immunohistochemistry and polymerase chain reaction in formalin-fixed, paraffin-embedded tumor tissue from cats with lymphosarcoma. 下载免费PDF全文
M L Jackson D M Haines S M Meric V Misra 《Canadian journal of veterinary research》1993,57(4):269-276
The prevalence of feline leukemia virus (FeLV) antigen and DNA was assessed in formalin-fixed, paraffin-embedded tumor tissues from 70 cats with lymphosarcoma (LSA). Tissue sections were tested for FeLV gp70 antigen using avidinbiotin complex (ABC) immunohistochemistry (IHC); DNA was extracted and purified from the same tissue blocks for polymerase chain reaction (PCR) amplification of a 166 base pair region of the FeLV long terminal repeat (LTR). Results were related to antemortem FeLV enzyme-linked immunosorbent assay (ELISA) for serum p27 antigen, anatomic site of LSA, and patient age. Viral DNA was detected by PCR in 80% of cases and viral antigen by IHC in 57% of cases. Seventeen cases were PCR-positive and IHC-negative; one case was PCR-negative and IHC-positive. Clinical records included FeLV ELISA results for 30 of 70 cats. All 19 ELISA-positive cats were positive by PCR and IHC; of the 11 ELISA-negative cats that were negative by IHC, seven were positive by PCR. When evaluated according to anatomic site, FeLV DNA and antigen were detected less frequently in intestinal LSAs than in multicentric and mediastinal tumors. Lymphosarcoma tissues from cats < 7 yr were several fold more likely to be positive for FeLV antigen by IHC than were tumors from cats > or = 7 yr. However, there was no significant difference in PCR detection of FeLV provirus between LSAs from cats < 7 yr and those > or = 7 yr.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
4.
Hematology and serum biochemistry values are reported for 33 Attwater's prairie chickens (Tympanuchus cupido attwateri) that were captive-reared at the San Antonio Zoo as part of a federal reintroduction program in Texas. Hematologic values include packed cell volume, and total and differential white blood cell counts. The biochemical values include concentrations of serum calcium, total protein, albumin, phosphorus, glucose, uric acid, and cholesterol. Mathematic computation of globulin concentration and albumin: globulin ratios were conducted. Also, determination of the serum activities of creatine kinase and aspartate aminotransferase was done. 相似文献
5.
Olson ME Bruce J 《The Canadian veterinary journal. La revue veterinaire canadienne》1986,27(12):523-527
This article describes the surgical procedures for the ovariectomy, ovariohysterectomy and orchidectomy in rodents and rabbits. The indications for each procedure are outlined and effective and safe anesthetics are described. Preoperative and postoperative care is also discussed. 相似文献
6.
Mitcham SA McGillivray SR Haines DM 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(3):98-100
Lytic lesions occurring in conjunction with plasma cell sarcoma (multiple myeloma) have rarely been reported in cats.
A plasma cell sarcoma was diagnosed in a 13 year old castrated male Siamese cat with hind limb paresis resulting from osteolysis of the second lumbar vertebra. Serum electrophoresis showed a monoclonal gammopathy. A uniform population of plasma cells was found in and around the second lumbar vertebra and in the bone marrow of the femora, humeri, pelvis and the fifth lumbar vertebra. The neoplastic cells were identified as IgA and kappa chain specific by direct immunofluorescence.
相似文献7.
Twenty-seven compounds were screened as potential inhibitors of juvenile hormone esterases. Of these compounds O-ethyl-S-phenyl phosphoramidothiolate provided the best inhibition for the cabbage looper, Trichoplusia ni (Hubner), and the yellow mealworm, Tenebrio molitor L., while the juvenile hormone esterases of the house fly, Musca domestica L., were best inhibited by a juvenoid carbamate (1-(m-phenoxy-N-ethyl carbamate)-3,7-dimethyl-7-methoxy-2E-octene). The inhibition patterns of T. ni and T. molitor are similar, while those of M. domestica are relatively different. Further studies on the juvenile hormone and α-napthyl acetate esterases of T. ni showed that they could be differentially inhibited. Diisopropyl phosphorofluoridate and an alkyl trifluoromethyl ketone selectively inhibit the hydrolysis of α-naphthyl acetate and juvenile hormone, respectively, while O-ethyl-S-phenyl phosporamidothiolate inhibits both enzymes. The juvenile hormone esterases of T. ni also appear to be unique enzymes that are selective for juvenile-hormone-like molecules. The in vivo inhibition of T. ni juvenile hormone esterases by O-ethyl-S-phenyl phosphoramidothiolate slows the in vivo hydrolysis of juvenile hormone and results in delayed pupation and malformed larvae that resemble larval-pupal intermediates. Thus, the esterases involved in juvenile hormone metabolism appear to be important in juvenile hormone regulation. 相似文献
8.
C. Rusterucci Z. Zhao K. Haines D. Mellersh M. Neumann R.K. Cameron 《Physiological and Molecular Plant Pathology》2005,66(6):120
As plants mature it has been observed that some become more resistant to normally virulent pathogens. The ability to manifest the Age-Related Resistance (ARR) response in Arabidopsis to Pseudomonas syringae pathovars tomato (Pst) coincided with the transition to flowering in plants both delayed and accelerated in the transition to flowering. ARR was also associated with a change in PR-1 gene expression, such that young plants expressed PR-1 abundantly at 3 days post inoculation (dpi) while mature plants expressed much less. The Arabidopsis ARR response requires SA accumulation via isochorismate synthase (ICS1) [24]. ICS1 was expressed one dpi with virulent and avirulent Pst in both young and mature plants. The ARR response was also effective versus avirulent Pst providing an additional 4-fold limitation in bacterial growth. Arabidopsis ARR was found to be ineffective against two necrotrophs, Erwinia carotovora subspecies carotovora (bacterium) and Botrytis cinerea (fungus) and one obligate biotroph, Erysiphe cichoracearum (fungus). However, mature wild type, SA-deficient sid2 and NahG plants supported little growth of the obligate biotrophic oomycete, Peronospora parasitica. Therefore ARR to P. parasitica appears to be SA-independent, however the level of ARR resistance was somewhat reduced in these mutants in some experiments. Thus, there may be numerous defence pathways that contribute to adult plant resistance in Arabidopsis. 相似文献
9.
C. Jacyn Baker Daniel P. Roberts Norton M. Mock Bruce D. Whitaker Kenneth L. Deahl Andrey A. Averyanov 《Physiological and Molecular Plant Pathology》2005,67(6):1322
The plant apoplast is an important mediator of communication between the cell cytoplasm and its surroundings. Plant cell suspensions offer a convenient model system to gain insight into apoplastic physiology. Here, we describe a novel phenomenon that took place when two naturally occurring phenolics were added together to either soybean or tobacco cell suspensions. Acetosyringone (AS) and/or hydroxyacetophenone (HAP), phenolics found in the extracellular/apoplast of tobacco cells, were added to soybean or tobacco cell suspensions undergoing an oxidative burst. Individually, AS appeared to be utilized as a typical peroxidase substrate to scavenge hydrogen peroxide, while HAP was utilized at a much lower rate. However, when added together the rate of utilization of both phenolics increased and surprisingly resulted in the production of hydrogen peroxide. We have further characterized this novel phenomenon in suspension cells. This study demonstrates that certain phenolics in plants can cause co-oxidation which, as in animals, could alter the structure and bioactivity of surrounding phenolics. 相似文献
10.
Clovis S. Palmer Jennifer A. Saleeba Bruce R. Lyon 《Physiological and Molecular Plant Pathology》2005,67(6):427
A phytotoxic protein that evokes the typical symptoms of Verticillium wilt disease in seedlings of Gossypium hirsutum L. (Upland cotton) was isolated from culture filtrates of Verticillium dahliae. The protein was purified by ammonium sulfate precipitation, Sephadex-G100 fractionation, and native PAGE. The 18.5 kDa protein, designated VD18.5, appears to be a single subunit protein with an isoelectric point between 3 and 5. VD18.5 induces symptoms of leaf dehydration, chlorosis, necrosis and stem discoloration in seedlings of the disease susceptible cotton cultivar Siokra 1–4. The LD50 of VD18.5 on protoplasts of Siokra 1–4 was 18 μg mL−1. VD18.5 had no noticeable effect on Pima S-7, which is a disease resistant cultivar. Phytotoxic activity was partially destroyed at high temperature and was abolished by digestion with proteinase K. Mass spectrometry fingerprinting and protein sequence data from VD18.5 yielded no significant matches when submitted to the Mascot search engine and NCBI non-redundant protein databases, respectively. These results suggest that VD18.5 is a novel protein that may be involved in the development of some of the symptoms associated with Verticillium wilt disease in the cotton plant. 相似文献