首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1009篇
  免费   29篇
  国内免费   2篇
林业   130篇
农学   34篇
基础科学   1篇
  118篇
综合类   42篇
农作物   54篇
水产渔业   172篇
畜牧兽医   404篇
园艺   11篇
植物保护   74篇
  2023年   2篇
  2022年   18篇
  2021年   50篇
  2020年   21篇
  2019年   18篇
  2018年   14篇
  2017年   24篇
  2016年   29篇
  2015年   28篇
  2014年   52篇
  2013年   61篇
  2012年   50篇
  2011年   66篇
  2010年   31篇
  2009年   40篇
  2008年   62篇
  2007年   57篇
  2006年   58篇
  2005年   50篇
  2004年   48篇
  2003年   60篇
  2002年   44篇
  2001年   38篇
  2000年   21篇
  1999年   10篇
  1998年   13篇
  1996年   3篇
  1995年   3篇
  1994年   3篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1988年   3篇
  1987年   11篇
  1986年   5篇
  1985年   5篇
  1984年   11篇
  1983年   4篇
  1982年   1篇
  1981年   3篇
  1980年   5篇
  1979年   1篇
  1978年   1篇
  1976年   2篇
  1971年   4篇
  1969年   1篇
  1967年   1篇
  1964年   1篇
  1963年   1篇
排序方式: 共有1040条查询结果,搜索用时 593 毫秒
181.
Six4, a small protein secreted by Fusarium oxysporum f. sp. lycopersici (Fol) in tomato xylem sap during infection, triggers Fol race 1-specific resistance (I) in tomato. SIX4 is regarded as an avirulence gene. Although SIX4 is considered unique to Fol race 1, we detected this gene in the cabbage yellows fungus F. oxysporum f. sp. conglutinans (Foc) by PCR. Because the genes from Foc and SIX4 in Fol were >99 % identical at the nucleotide level, the Foc gene was designated FocSIX4. The expression of FocSIX4 was detected by RT-PCR in stems and roots of cabbage 8 days after infection with Foc. In contrast with Fol, disruption of FocSIX4 in Foc did not increase virulence to Foc-resistant cabbage cvs. Shutoku-SP and Koikaze. On the contrary, the disruptants had reduced virulence not only on Foc-resistant cultivars but also on Foc-susceptible cv. Shikidori. These results suggested that FocSIX4 is involved in virulence, but not in avirulence, in the cabbage yellows fungus.  相似文献   
182.
Black scurf on carrot roots was found in Hokkaido, Japan, in 2010. An isolate of a binucleate Rhizoctonia was obtained from sclerotia on the root surface. This isolate was identified as anastomosis group (AG)-U based on cultural characteristics, hyphal fusions and the sequence of ribosomal DNA-internal transcribed spacer region. The AG-U isolate caused black scurf symptoms on carrot roots in an inoculation test. The reference isolate of Rhizoctonia solani AG-2-2 IV, which causes carrot root rot, a disease with symptoms that differ from the black scurf symptom. This is the first report of carrot black scurf caused by binucleate Rhizoctonia AG-U.  相似文献   
183.
A six-month-old Japanese Black bull was found to have no left testis in the scrotum. A fist-sized mass was palpated per rectum. Two months later, hCG was injected and blood samples were collected before and after injection. No testosterone response to hCG was observed. On the cut surface of the excised mass, most of the mass was composed of homogeneous adipose-like tissue. The rest of the surface was composed of a well-circumscribed testicular parenchyma-like tissue (18 × 16 × 15 mm). Histology revealed diffusely distributed mature adipocytes and septa of fibrous connective tissue. Neither germ cells nor spermatozoa were observed in the seminiferous tubules. A diagnosis was made of fibrolipoma and aspermatogenesis of the left cryptorchid testis.  相似文献   
184.
The first epidemiological survey of Border disease virus (BDV) was undertaken in small ruminants in Japan. Ovine sera, collected from the northern prefectures of Hokkaido, Aomori and Iwate, were examined for the presence of antibodies against BDV using the neutralization peroxidase-linked antibody test. Twenty-nine (17.6%) of one hundred and sixty-five samples were seropositive for BDV. Results were specific, excluding cross-reactions with bovine viral diarrhea virus (BVDV). Only one sample (0.6%) was positive for BVDV, and was negative for BDV. Despite serological evidence of virus circulation, there have been no clinical cases of border disease in sheep in Japan. Although no diagnostic measures were performed, the infection did not appear to be associated with a reduction in ewe fertility nor with lamb mortality.  相似文献   
185.
The prevalence of footpad dermatitis (FPD) in broiler chickens in Japan was investigated. In the first examination at slaughterhouses, lesions were commonly observed on the footpads of a total of 8,985 broiler chickens from 45 flocks on 36 farms. In 3 flocks, all the birds examined had lesions. In the other 42 flocks, the incidence of FPD ranged from 31.9% (81/254) to 99.5% (1/222). The footpad lesions were classified into 4 categories according to the severity of dermatitis as follows; score 0, 1,181 birds (13.1%); score 1, 2,992 birds (33.3%); score 2, 3,000 birds (33.4%); and score 3, 1,812 birds (20.2%). The mean scores of the flocks varied widely from 0.31 to 2.69. Males had higher mean scores than females. No significant differences were found between the mean scores of birds reared in windowless houses and those in open-sided houses. On 4 farms, the investigation was carried out in different seasons, and 3 of them showed higher mean scores in winter than in summer. Next, observation of 2,255 birds from 15 flocks on 5 farms during a 4-week rearing period revealed that FPD was already produced at 7 days of age and worsened with age.  相似文献   
186.
A single non-synonymous nucleotide substitution of guanine (G) for adenine (A) at position 2254 in the viral DNA polymerase gene (encoded by open reading frame [ORF] 30) of equine herpesvirus type 1 (EHV-1) has been significantly associated with neuropathogenic potential in strains of this virus. To estimate the prevalence of EHV-1 strains with the neuropathogenic genotype (ORF30 G(2254)) in the Hidaka district--a major horse breeding area in Japan--we analyzed the ORF30 genomic region in cases of EHV-1 infection in this area during the years 2001-2010. Of the 113 cases analyzed, 3 (2.7%) were induced by ORF30 G(2254) strains. This prevalence is lower than those observed in the U.S.A. (10.8-19.4%), Argentina (7.4%), France (24%), and Germany (10.6%).  相似文献   
187.
The present study investigated the basal levels and GnRH-induced responses of peripheral testosterone and estrogen in Holstein bulls with poor semen quality. On the basis of semen parameters, bulls (n=5) having poor semen quality were selected as experimental bulls, and good semen quality bulls (n=4) were used as control bulls. Both groups were treated intramuscularly once with GnRH (250 μg of fertirelin acetate). Blood samples were collected at -1 day (d), -30 min and 0 h (treatment) followed by every 30 min for 5 h and 1, 3 and 5 d post-GnRH treatment (PGT), and LH, testosterone and estradiol-17β (E(2)) concentrations were measured. The pretreatment concentrations were used as basal levels. The percentage increments based on the 0-h levels were calculated per bull for each sampling time until 5 h PGT, and differences were compared between the experimental and control groups. The PGT concentrations of testosterone and basal and PGT concentrations of E(2) were significantly lower in the experimental group. The testosterone increment in the experimental group was delayed and significantly lower from 1 to 5 h PGT than those in the control group. It can be suggested that bulls with poor semen quality have delayed and lower GnRH-induced testosterone response and may also have lower estrogen levels.  相似文献   
188.
In dogs injected intravenously with 400mg/m(2) cyclophosphamide (CPA), the peripheral neutrophil count decreased to less than 1000 cells/μL in 5-9 days. Treatment with purified recombinant canine granulocyte colony-stimulating factor (rcG-CSF), produced by brevibacillus expression system, at the nadir of the granulocyte count accelerated recovery from the CPA-induced neutropenia by 1-3 days. Therapeutic administration of rcG-CSF at doses of 2.5-10 μg/kg did not show any significant difference on the severity of neutropenia (the period that granulocyte counts were less than 2000 cells/μL). Administration of 2.5 μg/kg rcG-CSF 3 times per day 2-4 days or 3-5 days after CPA treatment not only accelerated recovery but also decreased the severity of neutropenia. No clinical signs of the rcG-CSF were observed. These results showed that the rcG-CSF is effective for treatment of neutropenia in dogs.  相似文献   
189.
Objective: To describe surgical repair of a large atrial septal defect (ASD) in a cat. Study Design: Clinical report. Animal: A 3‐year‐old, 3.3 kg, intact male Japanese domestic short‐haired cat. Methods: A 10.2‐mm‐diameter ASD detected by echocardiography was surgically corrected because pulmonary vascular resistance‐to‐systemic vascular resistance ratio (Qp/Qs) was 3.2. Using cardiopulmonary bypass (CPB), open surgical repair was achieved with an expanded polytetrafluoroethylene (e‐PTFE) graft. The priming volume of the CPB circuit was minimized by cutting the CPB tubing, and partially replacing the priming fluid with whole cat blood. To prevent hemodilution associated with use of cardioprotective agents, surgery was performed on the beating heart. Results: At 1‐year echocardiographic evaluation, the repair was intact, and at 3 years, the cat was alive without need of medication. Conclusions: Large ASD in a cat can be repaired using e‐PTFE under CPB.  相似文献   
190.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号