全文获取类型
收费全文 | 1182篇 |
免费 | 58篇 |
国内免费 | 1篇 |
专业分类
林业 | 51篇 |
农学 | 48篇 |
基础科学 | 7篇 |
206篇 | |
综合类 | 71篇 |
农作物 | 158篇 |
水产渔业 | 101篇 |
畜牧兽医 | 513篇 |
园艺 | 19篇 |
植物保护 | 67篇 |
出版年
2023年 | 12篇 |
2022年 | 10篇 |
2021年 | 49篇 |
2020年 | 21篇 |
2019年 | 25篇 |
2018年 | 33篇 |
2017年 | 31篇 |
2016年 | 51篇 |
2015年 | 47篇 |
2014年 | 48篇 |
2013年 | 63篇 |
2012年 | 88篇 |
2011年 | 102篇 |
2010年 | 60篇 |
2009年 | 43篇 |
2008年 | 87篇 |
2007年 | 68篇 |
2006年 | 55篇 |
2005年 | 52篇 |
2004年 | 49篇 |
2003年 | 48篇 |
2002年 | 55篇 |
2001年 | 47篇 |
2000年 | 33篇 |
1999年 | 15篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 4篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有1241条查询结果,搜索用时 31 毫秒
101.
Lee Y Lee O Cho J Shin H Choi Y Shim Y Choi W Shin H Lee D Lee G Shin S 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(5):497-502
The objective of this study was to determine relationship of gestational age with measurement of diameter of head, orbit, trunk, long and short axis of heart, aorta, placentome, umbilical cord and umbilical vein in Korean black goats. In this study, ten pregnant Korean black goats (Capra hircus aegagrus) were used. Pregnancy diagnosis was performed with a 5 MHz linear transducer and ultrasonographic scan were performed at 60, 75, 90, 105, 120 and 135 days after mating with a 4-9 MHz convex transducer. For accurate measurement, all fetal organs were measured at least 3 times. The diameter of head, orbit, trunk, long and short axis of heart, aorta, placentome, umbilical cord and umbilical vein were significantly increased with the gestational age (p<0.05). Of these parameters, trunk (r=0.8876; p<0.001), long axis of heart (r=0.9168; p<0.001) and short axis of heart (r=0.8819; p<0.001) proved to be the more effective measurements than other parameters, as it correlated well with gestational age. Results indicate that ultrasonic measurements of these parameters were useful methods to estimate gestational age in Korean black goat. 相似文献
102.
103.
Choi US Jeong SM Kang MS Jung IS Kim DY Lee CW 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2004,33(1):47-49
Abstract: An 18-month-old male Doberman Pinscher was referred to the Veterinary Medical Teaching Hospital of the College of Veterinary Medicine for an erythemic nodular mass on the right forelimb. The mass was diagnosed as cutaneous lymphoma, based on cytologic examination of a mass aspirate and histopathology. Using immunohistochemistry the neoplastic cells were positive for CD3 but negative for CD79a, E-cadherin, and pancytokeratin, confirming their origin as T lymphocytes. No tumor recurrence was noted 18 months after surgery. To our knowledge, this is the first report of a solitary nodular form of cutaneous lymphoma in a young dog. 相似文献
104.
OBJECTIVE: To examine clinical signs, virus infection and shedding, and transmission of swine influenza virus (SIV) subtype H1N2 among seropositive pigs. ANIMALS: Eighteen 3-week-old pigs with maternal antibodies against SIV subtypes H1N1, H3N2, and H1N2. PROCEDURE: Ten pigs (principal) were inoculated intranasally with subtype H1N2 and 2 groups of contact pigs (n = 4) each were mixed with principal pigs on day 7 (group 1) or 28 (group 2). Two principal pigs each were necropsied on days 4, 14, 21, 28, and 42 days after inoculation. Four pigs in each contact group were necropsied 35 and 14 days after contact. Virus excretion was evaluated after inoculation or contact. Lung lesions and the presence of SIV in various tissues were examined. RESULTS: Mild coughing and increased rectal temperature were observed in principal pigs but not in contact pigs. Nasal virus shedding was detected in all principal pigs from day 2 for 3 to 5 days, in group 1 pigs from day 2 for 4 to 9 days after contact, and in group 2 pigs from day 4 for 2 to 6 days after contact. Trachea, lung, and lymph node specimens from infected pigs contained virus. Antibody titers against all 3 subtypes in all pigs gradually decreased. CONCLUSIONS AND CLINICAL RELEVANCE: Protection from viral infection and shedding was not observed in pigs with maternal antibodies, but clinical disease did not develop. Vaccination programs and good management practices should be considered for control of SIV subtype H1N2 infection on swine farms. 相似文献
105.
106.
107.
Choi EW Lee CW 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2004,66(2):169-174
To develop an experimental animal model for immune-mediated glomerulonephritis and nephrotic syndrome, nine healthy dogs were sensitized by intravenous injection with 1 microg of endotoxin and 5 mg of native bovine serum albumin. After 1 week, 120 mg of cationized bovine serum albumin was injected intravenously 5 times a week. Among nine dogs, five dogs were confirmed as having developed glomerulonephritis and nephrotic syndrome by increase of urine protein-to-creatinine ratio (>1.0), hypoalbuminemia (<1.5 g/dl), hypercholesterolemia (>240 mg/dl), and edema. This model should be useful for studying immune-mediated glomerulonephritis and nephrotic syndrome. 相似文献
108.
Most studies of oocyte apoptosis have been performed in vitro and have employed the method of artificial induction of apoptosis by an anti-cancer agent. However, the process of oocyte death in vivo has not been clearly identified. To investigate the death process in unfertilized oocytes in vivo, we examined the cytochemical change of oocytes collected by oviduct flushing at various intervals after hCG injection. At each collection time, the collected oocytes were phenotypically classified under the microscope into four groups: single-cell oocytes (non-activated and without a nucleus and cytokinesis), activated oocytes (single-, 2- or 4-cell with a nucleus), fragmented oocytes, and dead oocytes. The number of single oocytes decreased and dead oocytes increased with the lapse of time, but the number of activated oocytes or fragmented oocytes did not. Also, most of the dead oocytes observed were single cell. At each time point, single oocytes were stained with anti-tubulin antibody to examine their spindle status. At 24 h after hCG injection, all ovulated oocytes had a normal bipolar spindle, while at 64 h all single-cell oocytes had no spindle. From these observations, we concluded that most oocyte deaths in vivo occur in the single oocyte stage, not in activated or fragmented oocytes. 相似文献
109.
Genotypic prevalence of the adhesin involved in diffuse adherence in Escherichia coli isolates in pre-weaned pigs with diarrhoea in Korea 总被引:1,自引:0,他引:1
Ha SK Choi C Jung K Kim J Han DU Ha Y Lee SD Kim SH Chae C 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2004,51(4):166-168
A total of 1002 Escherichia coli strains isolated from pre-weaned pigs with diarrhoea on 1114 swine farms were screened for the presence of the adhesin involved in diffuse adherence (AIDA) gene by polymerase chain reaction (PCR). Escherichia coli isolates that carried AIDA genes were also tested by PCR for the detection of five fimbriae (F4, F5, F6, F18 and F41), heat-stable (STa, STb) and heat-labile (LT) enterotoxin, enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1), and Shiga toxin 2 oedema disease (Stx2e) genes. Twenty-three (2.3%) of the 1002 E. coli isolates carried the gene for AIDA. Among 23 isolates shown to carry genes for AIDA, three carried the AIDA gene as the only shown virulence factor. Other isolates carried other virulence factor genes in addition to AIDA. Four isolates carried genes for at least one of the fimbrial adhesins and enterotoxins. Sixteen isolates carried genes for enterotoxins only. The AIDA may represent an additional virulence determinant in pre-weaned pigs with diarrhoea. 相似文献
110.
The effect of spraying exogenous plant hormone methyl jasmonate (MeJA) upon radish sprout (Raphanus sativus L.) was investigated in aspects of total phenolic content (TPC), isothiocyanate content, antioxidant activity of the radish extract, and enzymatic activities of phenylalanine ammonia lyase (PAL) and myrosinase. The MeJA treatment significantly increased the TPC that resulted in the increased DPPH* (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging capacity. In addition, the PAL activity also increased by 60% at 24 h after MeJA treatment. However, the same treatment decreased the amount of 4-methylthio-3-butenylisothiocyanate (MTBITC), a major isothiocyanate in radish sprout and the activity of myrosinase, an enzyme related to produce isothiocyanates. 相似文献