全文获取类型
收费全文 | 1036篇 |
免费 | 38篇 |
国内免费 | 2篇 |
专业分类
林业 | 10篇 |
农学 | 18篇 |
基础科学 | 16篇 |
43篇 | |
综合类 | 526篇 |
农作物 | 14篇 |
水产渔业 | 11篇 |
畜牧兽医 | 263篇 |
园艺 | 23篇 |
植物保护 | 152篇 |
出版年
2022年 | 9篇 |
2021年 | 7篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 13篇 |
2016年 | 8篇 |
2015年 | 12篇 |
2014年 | 11篇 |
2013年 | 26篇 |
2012年 | 49篇 |
2011年 | 51篇 |
2010年 | 26篇 |
2009年 | 11篇 |
2008年 | 49篇 |
2007年 | 47篇 |
2006年 | 56篇 |
2005年 | 44篇 |
2004年 | 59篇 |
2003年 | 56篇 |
2002年 | 47篇 |
2001年 | 38篇 |
2000年 | 51篇 |
1999年 | 27篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 11篇 |
1994年 | 7篇 |
1993年 | 14篇 |
1992年 | 25篇 |
1991年 | 24篇 |
1990年 | 15篇 |
1989年 | 15篇 |
1988年 | 11篇 |
1987年 | 22篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 9篇 |
1982年 | 12篇 |
1981年 | 8篇 |
1980年 | 9篇 |
1976年 | 6篇 |
1973年 | 13篇 |
1972年 | 10篇 |
1971年 | 11篇 |
1970年 | 9篇 |
1969年 | 6篇 |
1968年 | 8篇 |
1967年 | 10篇 |
1966年 | 13篇 |
排序方式: 共有1076条查询结果,搜索用时 15 毫秒
21.
22.
N.D. Cohen VMD MPH PhD N.A. Faber DVM G.W. Brumbaugh DVM PhD 《Journal of Equine Veterinary Science》1995,15(11)
All horses diagnosed with duodenitis/proximal jejunitis (DPJ) at the Texas Veterinary Medican Center between January 1, 1987 and July 1, 1993 were included in a retrospective study to evaluate the therapeutic and prognostic value of bethanechol and metoclopramide as gastrointestinal prokinetic drugs in horses with DPJ treated at our clinic, and to compare the clinical outcome of horses with DPJ treated with these drugs and those with DPJ that were not treated. During the study period, 70 horses diagnosed with DPJ were admitted to the clinic. Of these 70 horses, 18(25.7%) were treated with bethanechol, metoclopramide, or both; 13 of the 18 treated horses received more than one dose of either drug. No adverse effects of treatment with these drugs were noted. A precise therapeutic plan and clinical benefit of bethanechol, metoclopramide, or both coul not be determined from this retrospective study. The use of these gastrointestinal prokinetic drugs in horses with DPJ appeared to have prognostic value. Horses that did not respond to treatment with these gastrointestinal prokinetic drugs within 24 hours were not discharged alive. 相似文献
23.
Tamara M. Cohen Shauna Blois Andrew R. Vince 《The Canadian veterinary journal. La revue veterinaire canadienne》2016,57(5):483-486
A 22-month-old indoor/outdoor neutered male domestic short-haired cat had a history of progressive lethargy, vomiting, and decreased appetite. Abdominal ultrasound revealed an irregular hyperechoic mass in the mid-abdomen. He was unresponsive to symptomatic medical management and was euthanized after 3 days of hospitalization. A diagnosis of disseminated extraintestinal toxoplasmosis was made based on the finding of intracytoplasmic protozoan parasites on histopathological examination of mesenteric lymph nodes, hepatic and intestinal samples, and on immunohistochemistry. 相似文献
24.
Nephrogenic diabetes insipidus was diagnosed in a dog with an intestinal leiomyosarcoma. The diagnosis of nephrogenic diabetes insipidus was made on the basis of results of serum biochemical tests, urinalyses, and a water-deprivation test, along with a lack of response to exogenous administration of vasopressin following the water-deprivation test. The temporal association between resection of the intestinal mass and resolution of clinical signs of diabetes insipidus (i.e., polyuria and polydipsia) and between recurrence of clinical signs and detection of metastatic disease suggests that there may have been a causal relationship, and nephrogenic diabetes insipidus may have developed as a paraneoplastic syndrome in this dog. 相似文献
25.
Cohen ND Berry SM Peloso JG Mundy GD Howard IC 《Journal of the American Veterinary Medical Association》2000,216(8):1273-1278
OBJECTIVE: To determine the association between high-speed exercise and risk of injury while racing among Thoroughbreds in Kentucky. DESIGN: Matched case-control study. ANIMALS: 206 Thoroughbreds that sustained a musculoskeletal injury while racing and 412 Thoroughbreds that were not injured during the same races. PROCEDURE: Data regarding official timed workouts and races and the Beyer's numbers for the 3 races before the race during which injury occurred were extracted from past performance charts and compared between injured horses and control horses. RESULTS: For injured horses, cumulative distance of high-speed exercise during the 1- and 2-month periods prior to the race in which injury occurred was significantly less than that of control horses; for either period, a difference of 10 furlongs was associated with approximately 2-fold greater risk of injury. Beyer's numbers were significantly higher for injured horses than for control horses. These effects remained significant after adjusting for age and results of prerace physical inspection. CONCLUSIONS AND CLINICAL RELEVANCE: In Kentucky, injured horses had significantly less cumulative high-speed exercise than did control horses during the 1- and 2-month periods prior to the race in which injury occurred. These results differ from those observed in California. The association of injury with cumulative high-speed exercise appears to vary among regions in the United States. 相似文献
26.
27.
Estimating the Sensitivity and Specificity of Real‐Time Quantitative PCR of Fecal Samples for Diagnosis of Rhodococcus equi Pneumonia in Foals 下载免费PDF全文
S.D. Shaw N.D. Cohen M.K. Chaffin G.P. Blodgett M. Syndergaard D. Hurych 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(6):1712-1717
Background
Real‐time, quantitative PCR (qPCR) methods for detecting Rhodococcus equi in feces have been developed as a noninvasive, rapid diagnostic test for R. equi pneumonia, but have not been evaluated in a large population of foals.Objective
The objective of this study was to evaluate the clinical utility of fecal PCR as a diagnostic test for R. equi pneumonia in foals using receiver operating characteristic (ROC) methods.Animals
186 foals born in 2011 at an R. equi‐endemic ranch in Texas.Methods
Fecal samples were collected at the time of onset of clinical signs for pneumonic foals (n = 31). Foals with pneumonia were matched by age and birth date to healthy (n = 31) and subclinical (n = 124) control foals; fecal samples were collected from these controls. DNA was extracted from feces using commercial kits and concentration of virulent R. equi in feces was determined by qPCR.Results
Concentration of R. equi in feces differed significantly (P < .05) among groups. The area under the ROC curve for fecal qPCR for diagnosis of R. equi pneumonia was 89% (95% CI, 83–99), with a sensitivity of 94% and specificity of 72%.Conclusions and Clinical Importance
qPCR of feces can be useful as an alternative to tracheobronchial aspiration for the diagnosis of R. equi in foals with clinical signs of pneumonia. Caution should be used in extrapolating results of this study to other populations because fecal concentration of R. equi might vary by geographic location or management practices. 相似文献28.
29.
Y. Burger N. Katzir G. Tzuri V. Portnoy U. Saar S. Shriber R. Perl-Treves R. Cohen † 《Plant pathology》2003,52(2):204-211
Screening of genotypes of melon ( Cucumis melo ) for resistance to wilt caused by Fusarium oxysporum f.sp. melonis is often characterized by wide variability in their responses to inoculation, even under carefully controlled conditions. The variability at the seedling stage of 17 genotypes susceptible to race 1 was examined in growth-chamber experiments. Disease incidence varied from 0 to 100% in a genotype-dependent manner. Using four combinations of light (60 and 90 µ E m−2 s−1 ) and temperatures of (27 and 31°C), only light intensity showed a statistically significant effect. Marker-assisted selection for fusarium resistance breeding using cleaved amplified polymorphic sequence (CAPS) and sequence-characterized amplified region (SCAR) markers were compared using a single set of genotypes that included 24 melon accessions and breeding lines whose genotype regarding the Fom-2 gene was well characterized. The practical value of the markers for discriminating a range of genotypes and clarifying the scoring of phenotypes was also tested using a segregating breeding population which showed codominant SCAR markers to be useful in marker-assisted selection. 相似文献
30.
Roussel AJ Cohen ND Hooper RN 《Journal of the American Veterinary Medical Association》2000,216(5):730-733
OBJECTIVE: To assess signalment, history, results of clinical and laboratory testing, and outcome for beef cattle with a left displaced abomasum (LDA), right displaced abomasum (RDA), or abomasal volvulus (AV). DESIGN: Retrospective study. ANIMALS: 19 beef cattle with an AV, LDA, or RDA. PROCEDURE: Signalment; history; results of physical examination, diagnostic testing, and surgical exploration; and condition of the animal at discharge were obtained from medical records. RESULTS: Fourteen cattle had an AV, 4 had an RDA, and 1 had an LDA. Duration of clinical signs ranged from 1 to 21 days. Eighteen cattle had an AV or RDA; 7 were Brahmans, 12 were males, and median age was 10 months. Abdominal distention was observed in 11 cattle, heart rate of > or = 100 beats/minute was detected in 14, and the abomasum was palpable per rectum in all cattle in which per rectal examination was performed. Leukocytosis, neutrophilia, hyperglycemia, azotemia, hypochloremia, and hypokalemia were common laboratory findings. At surgery, 3 cattle with an AV or RDA had a ruptured abomasum. Of the remaining 15 cattle, 12 survived. CONCLUSIONS: Clinical course in beef cattle with an AV or RDA was more protracted than that typically associated with these conditions in dairy cattle, but survival rate in beef cattle that did not have rupture of the abomasum was similar to that of dairy cattle. CLINICAL RELEVANCE: Abomasal displacement should be considered for beef cattle with abdominal distention. Prognostic indicators recommended for use in dairy cattle may not be useful for beef cattle. 相似文献