全文获取类型
收费全文 | 7190篇 |
免费 | 351篇 |
国内免费 | 6篇 |
专业分类
林业 | 529篇 |
农学 | 149篇 |
基础科学 | 36篇 |
1316篇 | |
综合类 | 1227篇 |
农作物 | 230篇 |
水产渔业 | 560篇 |
畜牧兽医 | 2739篇 |
园艺 | 197篇 |
植物保护 | 564篇 |
出版年
2023年 | 59篇 |
2022年 | 75篇 |
2021年 | 148篇 |
2020年 | 152篇 |
2019年 | 181篇 |
2018年 | 187篇 |
2017年 | 153篇 |
2016年 | 186篇 |
2015年 | 166篇 |
2014年 | 190篇 |
2013年 | 273篇 |
2012年 | 477篇 |
2011年 | 607篇 |
2010年 | 297篇 |
2009年 | 246篇 |
2008年 | 498篇 |
2007年 | 527篇 |
2006年 | 469篇 |
2005年 | 437篇 |
2004年 | 413篇 |
2003年 | 383篇 |
2002年 | 393篇 |
2001年 | 75篇 |
2000年 | 55篇 |
1999年 | 65篇 |
1998年 | 51篇 |
1997年 | 52篇 |
1996年 | 43篇 |
1995年 | 47篇 |
1994年 | 45篇 |
1993年 | 47篇 |
1992年 | 35篇 |
1991年 | 36篇 |
1990年 | 33篇 |
1989年 | 38篇 |
1988年 | 30篇 |
1987年 | 30篇 |
1986年 | 27篇 |
1985年 | 39篇 |
1984年 | 27篇 |
1983年 | 29篇 |
1982年 | 20篇 |
1981年 | 15篇 |
1980年 | 23篇 |
1979年 | 24篇 |
1978年 | 14篇 |
1977年 | 17篇 |
1975年 | 15篇 |
1974年 | 13篇 |
1973年 | 20篇 |
排序方式: 共有7547条查询结果,搜索用时 0 毫秒
121.
Peters SM Yancy H Deaver C Jones YL Kenyon E Chiesa OA Esparza J Screven R Lancaster V Stubbs JT Yang M Wiesenfeld PL Myers MJ 《Veterinary immunology and immunopathology》2012,148(3-4):236-242
Non-steroidal anti-inflammatory drugs (NSAID) are a family of chemicals that function to reduce pain, fever, and inflammation, and they are commonly used in people and animals for this purpose. Currently there are no NSAIDs approved for the management of inflammation in swine due to a lack of validated animal models and suitable biomarkers to assess efficacy. A previous in vitro study examining biomarkers of inflammation identified fourteen genes that were significantly altered in response to Escherichia coli lipopolysaccharide (LPS)-induced inflammation. In the present study, five of those fourteen genes were tested in vivo to determine if the same effects observed in vitro were also observed in vivo. Plasma levels of prostaglandin E(2) (PGE(2)), an essential mediator of fever and inflammation, were also determined. Two groups of swine were stimulated with LPS with the second group also treated with flunixin meglumine. Blood was collected at 0, 1, 3, 6, 8, 24, and 48h post LPS-stimulation. The RNA was extracted from the blood and quantitative real-time-PCR (qRT-PCR) was utilized to determine the expression patterns of CD1, CD4, serum amyloid A2 (SAA2), Caspase 1, and monocyte chemoattractant protein 1 (MCP-1). The LPS-stimulated animals demonstrated a statistically significant alteration in expression of SAA2 and CD1 at 3h post-stimulation. Flunixin meglumine treated animals' demonstrated reduced expression of CD1 in comparison to the LPS-stimulated swine at 24 and 48h post LPS-stimulation. Flunixin meglumine treated animals exhibited reduced expression of SAA2 at 48h post-stimulation compared to LPS-stimulated swine. Swine treated with LPS demonstrated statistically significant increases in plasma PGE(2) at 1h post-stimulation. Swine treated with flunixin meglumine had no increase in plasma PGE(2) levels at any time. These results demonstrate that PGE(2) production, along with two out of five genes (SAA2 and CD1) have the potential to serve as early biomarkers of inflammation as well as indicators of NSAID efficacy. 相似文献
122.
Michael Klotsman Gayatri Sathyan Wayne H. Anderson Oliver A. Garden Padmaja Shivanand 《Journal of veterinary pharmacology and therapeutics》2019,42(2):127-138
Mycophenolic acid (MPA), a noncompetitive, selective and reversible inhibitor of inosine 5′‐monophosphate dehydrogenase (IMPDH), is an immunosuppressive agent that has a long history in medicine. Mechanistically, the inhibition of IMPDH leads to the selective and eventual arrest of T‐ and B‐lymphocyte proliferation. Mycophenolate mofetil (MMF), the first MPA‐based product to receive marketing approval over two decades ago, was originally indicated for the prophylaxis of organ rejection in human transplant patients. Given its broad immunosuppressive properties and ability to selectively inhibit lymphocyte division and effector functions, the clinical utility of MPA was subsequently explored in a host of autoimmune diseases. Human clinical studies have shown MPA to be safe and effective and support its off‐label administration for immune‐mediated diseases such as lupus, myasthenia gravis and atopic dermatitis. MMF became generically available in the United States in 2008, and its clinical utility is increasingly being explored as a treatment option for dogs with immune‐mediated diseases. This review summarizes the available literature for MPA pharmacokinetics and pharmacodynamics, and the current status of MPA as a treatment for client‐owned dogs diagnosed with immune‐mediated diseases. 相似文献
123.
124.
Mitchell A. Crystal DVM Dominique G. Penninck DVM Michael E. Matz DVM Susan H. Pearson BA Greg O. Freden DVM Richard M. Jakowski DVM 《Veterinary radiology & ultrasound》1993,34(6):438-444
The purpose of this study was to evaluate the usefulness of ultrasound-guided fine-needle aspiration biopsy and core biopsy in the diagnosis of infiltrative gastrointestinal diseases. Six dogs and seven cats with clinical signs of gastrointestinal disease underwent ultrasonography and intestinal lesions were identified. One or more ultrasound-guided fine-needle aspiration biopsy and/or core biopsy procedures were performed in each patient. Each patient also underwent one of the following additional procedures for comparison of results: 1) surgery (n=4), 2) endoscopy (n=2), 3) post mortem exam (n=3), and, 4) for lymphoma diagnosed with ultrasound-guided procedures, response to chemotherapy (n=4). Correct diagnoses were obtained in nine of the 13 patients, incorrect diagnoses in two of the 13 patients, and inconclusive diagnoses in two of the thirteen patients. Of the 16 total ultrasound-guided procedures performed, ten were confirmed as correct, three as incorrect, and three were non-diagnostic. Intestinal lesions with bowel wall thickness greater than 2.0 cm had a higher percentage of correct diagnoses than lesions of lesser wall thickness. Gastric lesions had a higher percentage of correct diagnoses than small and large intestinal lesions. Malignant lesions had a higher percentage of correct diagnoses than benign lesions. There were no complications. Ultrasound-guided gastrointestinal fine-needle aspiration biopsy and core biopsy appears to be a safe, accurate, and rapid procedure for use in the diagnosis of infiltrative gastrointestinal disease. 相似文献
125.
Shuhei ENJOJI Ryotaro YABE Nobuyuki FUJIWARA Shunya TSUJI Michael P. VITEK Takuya MIZUNO Takayuki NAKAGAWA Tatsuya USUI Takashi OHAMA Koichi SATO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(11):1451-1456
Canine melanoma is one of the most important diseases in small animal medicine.
Protein phosphatase 2A (PP2A), a well conserved serine/threonine phosphatase, plays a
critical role as a tumor suppressor. SET/I2PP2A is an endogenous inhibitor for PP2A, which
directly binds to PP2A and suppresses its phosphatase activity. Elevated SET protein
levels have been reported to exacerbate human tumor progression. The role of SET in canine
melanoma, however, has not been understood. Here, we investigated the potential
therapeutic role for SET inhibitors in canine melanoma. The expression of SET protein was
observed in 6 canine melanoma cell lines. We used CMeC-1 cells (primary origin) and CMeC-2
cells (metastatic origin) to generate cell lines stably expressing SET-targeting shRNAs.
Knockdown of SET expression in CMeC-2, but not in CMeC-1, leads to decreased cell
proliferation, invasion and colony formation. Phosphorylation level of p70 S6 kinase was
decreased by SET knockdown in CMeC-2, suggesting the involvement of mTOR (mammalian target
of rapamycin)/p70 S6 kinase signaling. The SET inhibitors, OP449 and FTY720, more
effectively killed CMeC-2 than CMeC-1. We observed PP2A activation in CMeC-2 treated with
OP449 and FTY720. These results demonstrated the potential therapeutic application of SET
inhibitors for canine melanoma. 相似文献
126.
127.
Cortez Alcobedes Maria M. Boggio Gonzalo Guerra Ma. de Lourdes de Gavidia Magda Rodríguez Rojas Reyes Glenda C. Ferrer Elizabeth Lares Maria Alviarez Yenny Harrison Leslie J. S. Parkhouse R. Michael E. 《Tropical animal health and production》2010,42(3):531-537
There is a paucity of quantitative data on the status of porcine cysticercosis in Venezuela, information which is essential
for understanding the level of disease transmission. This study was, therefore, conducted in a typical small rural community
in Yaracuy State, Venezuela, where previous cases of human Taenia solium taeniasis/cysticercosis had been reported and where the free-ranging pig management practices and the lack of rudimentary
sanitary facilities indicated an obvious risk for transmission of the disease. Serum samples from 52 village pigs were screened
by enzyme-linked immunosorbent assays for anti-cysticercal antibodies (Ab-ELISA), using T. solium cyst fluid as the antigen and the HP10, monoclonal antibody-based, antigen trapping ELISA for parasite antigen (HP10 Ag-ELISA).
Significantly, a high proportion of the animals (65.4% for the Ab-ELISA and 42.3% for the HP10 Ag-ELISA) were sero-positive.
Five of the pigs, which were selected on that basis of positive tongue palpation, were killed for autopsy, and large numbers
of viable cysticerci were found in the carcases. This unequivocal documentation of porcine cysticercosis in Venezuelan pigs
presents clear evidence that T. solium is actively transmitted in Venezuela. Further detailed studies and implementation of appropriate control measures are therefore
indicated. 相似文献
128.
To estimate the prevalence of enteric parasites and selected vector-borne agents of dogs and cats in San Isidro de El General, Costa Rica, fecal and serum samples were collected from animals voluntarily undergoing sterilization. Each fecal sample was examined for parasites by microscopic examination after fecal flotation and for Giardia and Cryptosporidium using an immunofluorescence assay (IFA). Giardia and Cryptosporidium IFA positive samples were genotyped after PCR amplification of specific DNA if possible. The seroprevalence rates for the vector-borne agents (Dirofilaria immitis, Borrelia burgdorferi, Ehrlichia canis, and Anaplasma phagocytophilum) were estimated based on results from a commercially available ELISA. Enteric parasites were detected in samples from 75% of the dogs; Ancylostoma caninum, Trichuris vulpis, Giardia, and Toxocara canis were detected. Of the cats, 67.5% harbored Giardia spp., Cryptosporidium spp., Ancylostoma tubaeforme, or Toxocara cati. Both Cryptosporidium spp. isolates that could be sequenced were Cryptosporidium parvum (one dog isolate and one cat isolate). Of the Giardia spp. isolates that were successfully sequenced, the 2 cat isolates were assemblage A and the 2 dog isolates were assemblage D. D. immitis antigen and E. canis antibodies were identified in 2.3% and 3.5% of the serum samples, respectively. The prevalence of enteric zoonotic parasites in San Isidro de El General in Costa Rica is high in companion animals and this information should be used to mitigate public health risks. 相似文献
129.
Reichard MV Tiernan KE Paras KL Interisano M Reiskind MH Panciera RJ Pozio E 《Veterinary parasitology》2011,182(2-4):368-371
We determined the prevalence and mean intensity of Trichinella sp. infection in coyotes from six counties in Oklahoma and one in northern Texas. Tongues from 77 coyotes were examined using histology and artificial tissue digestion. Histological examination showed a prevalence of 3.9% (3 of 77) whereas the prevalence was 6.5% (5 of 77) based on artificial digestion of 5.0 g of muscle from coyote tongues. One sample was positive for Trichinella sp. on histology but negative by artificial digestion. Combining data from both diagnostic techniques showed that six of 77 (7.8%) coyotes were infected with Trichinella spp. The mean intensity of Trichinella sp. larvae ranged from 0.2 to 66.2 with an average of 16.0 larvae per gram (LPG) of tongue. Genotyping results demonstrated that the coyotes were infected with Trichinella murrelli. This is the first report of T. murrelli infection in coyotes in Oklahoma. T. murrelli had previously been isolated from coyotes in Texas. 相似文献
130.
Bennett AD Gunn-Moore DA Brewer M Lappin MR 《Journal of Feline Medicine and Surgery》2011,13(8):553-557
The objective of this study was to determine the prevalence rates for select infectious agents of cats presented to the Royal (Dick) School of Veterinary Studies at the University of Edinburgh, Scotland. Whole blood, serum, and oral mucosal and nail bed swabs were collected. While Ehrlichia species, Anaplasma species or Rickettsia felis DNA were not amplified from any cat, 44.2% of the cats had evidence of infection or exposure to either a Bartonella species (15.3% were seropositive and 5.8% polymerase chain reaction (PCR) positive), a haemoplasma (28.6% PCR positive), and/or Toxoplasma gondii (19.2% seropositive). No Bartonella species DNA was amplified from the nail or oral mucosal swabs despite a 5.8% amplification rate from the blood samples. This finding likely reflects the absence of Ctenocephalides felis infection from our study population, as this organism is a key component for Bartonella species translocation in cats. The results from this study support the use of flea control products to lessen exposure of cats (and people) to Bartonella species and support discouraging the feeding of raw meat to cats and preventing them from hunting to lessen T gondii infection. 相似文献