全文获取类型
收费全文 | 27380篇 |
免费 | 1831篇 |
国内免费 | 1678篇 |
专业分类
林业 | 2164篇 |
农学 | 2773篇 |
基础科学 | 1429篇 |
4530篇 | |
综合类 | 5715篇 |
农作物 | 1255篇 |
水产渔业 | 1550篇 |
畜牧兽医 | 8735篇 |
园艺 | 617篇 |
植物保护 | 2121篇 |
出版年
2023年 | 267篇 |
2022年 | 492篇 |
2021年 | 667篇 |
2020年 | 639篇 |
2019年 | 745篇 |
2018年 | 686篇 |
2017年 | 870篇 |
2016年 | 784篇 |
2015年 | 956篇 |
2014年 | 917篇 |
2013年 | 1284篇 |
2012年 | 1353篇 |
2011年 | 1459篇 |
2010年 | 1309篇 |
2009年 | 1214篇 |
2008年 | 1292篇 |
2007年 | 1381篇 |
2006年 | 1223篇 |
2005年 | 1205篇 |
2004年 | 731篇 |
2003年 | 672篇 |
2002年 | 587篇 |
2001年 | 992篇 |
2000年 | 975篇 |
1999年 | 953篇 |
1998年 | 465篇 |
1997年 | 435篇 |
1996年 | 356篇 |
1995年 | 397篇 |
1994年 | 332篇 |
1993年 | 322篇 |
1992年 | 491篇 |
1991年 | 477篇 |
1990年 | 414篇 |
1989年 | 348篇 |
1988年 | 338篇 |
1987年 | 371篇 |
1986年 | 279篇 |
1985年 | 202篇 |
1984年 | 177篇 |
1983年 | 158篇 |
1982年 | 105篇 |
1981年 | 88篇 |
1980年 | 85篇 |
1979年 | 141篇 |
1978年 | 94篇 |
1977年 | 73篇 |
1975年 | 77篇 |
1974年 | 79篇 |
1969年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Y Sugawara K Hirasawa M Takeda J S Han K Doi 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1991,53(3):463-468
One-month-old Syrian hamsters of the APA and Std: golden strains were inoculated intraperitoneally with 10(5) PFU/head of the D variant of encephalomyocarditis (EMC) virus and examined virologically and pathologically up to 7 days after inoculation. APA hamsters developed apparent hyperglycemia due to pancreatic islet cell damage while Std:golden hamsters did not. Hamsters of both strains showed clear histopathologic changes in the testis with prominent viral replication as well as in the brain, heart and exocrine pancreas. The susceptibility to EMC virus-infection was higher in males than in females and in APA than in Std: golden hamsters. 相似文献
82.
83.
H K Pradhan G C Mohanty W Y Lee B Patnaik 《Veterinary immunology and immunopathology》1991,29(3-4):229-238
Antibody directed against Marek's disease-associated tumor surface antigen (MATSA) was eluted from tumor cells of lymphomas and peripheral blood lymphocytes that were isolated from Marek's disease virus-infected chickens. Feather follicular Marek's disease virus (MDV) antigen could not be demonstrated with this antibody by indirect immunofluorescent (IF) staining. Monoclonal antibody directed against MATSA could completely block the activity of eluted antibody and vice versa. By indirect IF staining using eluted antibody and fluorescein isothiocyanate (FITC) labelled antichicken globulin conjugate. MATSA-bearing cells were detected in MDV infected and herpes virus of turkey (HVT) vaccinated birds. Blocking of immunoglobulin molecules present on B-cells by anti-chicken globulin is critical in this test. 相似文献
84.
为了控制疫情的发生、蔓延,防止造成重大的经济损失,保护动物及人类的安全和健康,我国在国道省际交界处设立了动物疫病监督检查站,实施对即将进入流通领域的动物及其产品的监督检查工作。这一举措在动物防疫工作中的作用是非常重要的,但是一些公路动物疫 相似文献
85.
In this paper, we consider the inverse problems for a kinds of normal matrices. Some necessary and sufficient conditions for existence of solution of these problems are given. The expression of the general solution is given. 相似文献
86.
对偏调谐类单调谐滤波器提出了非线性的束优化模型,运用大系统理论协调优化单调谐滤波器和高通滤波器,实例计算表明,该方法是对以往单调谐滤波器设计计算方法的一大改进。 相似文献
87.
Y Takahashi M Iida Y Nishida Y Kido 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1989,51(5):995-1001
Eight calves, weighing 50-150 kg, were given intramuscularly 5 ml of ampicillin (ABPC) aqueous suspensions (200 mg potency/ml) in their right and left gluteal and femoral regions. All calves were sacrificed one hour later to confirm the location of injected drug. The drug was found in a muscle layer when injected with a needle 15 mm long to the following positions, 1. the midpoint between the central position of the gluteal region (CG) and the tuber coxae (M-CTc), 2. the midpoint between CG and the tuber ossis ischii (M-CTo), 3. the central position of M. semimembranaceus in the femoral region (CF). Seven calves, weighing 130-150 kg, were given intramuscularly 5 ml of ABPC suspensions at M-CTo and CF and sacrificed one hour (4 calves) and 3 days (3 calves) later. ABPC diffused along the long axis of the muscle fibers but not to the radial direction. ABPC was detected only in the injected muscle layer even after 3 days indicating that the drug did not diffuse to the neighboring muscles. In the injected muscle layer, concentration of ABPC was remarkably different from part to part. From these results, sampling of the injected muscle for the drug residue study was proposed as follows: 1. isolate about 100 g of muscle just under the stick point marked on the skin considering the direction of drug diffusion, and 2. isolate separately about 200 g of the surrounding muscle to confirm if the sampling is appropriate. 相似文献
88.
用提纯的OPPV细胞抗原免疫BALB/c小鼠脾脏与SP2/0小鼠骨髓细胞融合,融合率为70%,以ELISA双抗体夹心法进行检测,阳性率为20%,经过有限稀释法克隆出1A6、2B8、1G3、2G44株分泌抗OPPV抗原的单克隆体杂交瘤细胞株.选择抗体分泌滴度高的1A6细胞进行了较详细的研究,结果表明,其核内染色体数为96~110条,抗体属性为IgG1,轻链为K链,IFA试验表明产生的McAb对OPPV有特异性,细胞传30代并在液氮中保存半年后复苏仍能稳定地分泌抗OPPV McAb,细胞分泌抗体的ELISA滴度腹水为6.4×104,上清为640,McAb经硫基乙醇还原后在SDS-PAG上呈现2条区带,一条为重链部分,MW50000,另一条为轻链部分,MW为25000. 相似文献
89.
Cellular injury and lipid peroxidation induced by hexavalent chromium in isolated rat hepatocytes 总被引:1,自引:0,他引:1
S Ueno N Susa Y Furukawa K Aikawa I Itagaki 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1989,51(1):137-145
In order to elucidate the relationship between cellular injury and lipid peroxidation induced by hexavalent chromium (CrVI), isolated rat hepatocytes treated with any one of scavengers of active oxygen species, antioxidants or antichromium agent were incubated with K2Cr2O7 as CrVI (1 mM Cr). After the incubation, the development of lipid peroxidation was determined as thiobarbituric acid (TBA)-reacting materials in total lipid extracts from the incubated hepatocytes. Cellular injury was observed as a leakage of lactate dehydrogenase (LDH) from hepatocytes into incubation medium. The contents of reduced glutathione (GSH) in hepatocytes were also assessed. Results obtained were as follows: (1) CrVI facilitated lipid peroxidation in isolated hepatocytes after 20 min of incubation. On the other hand, the cellular injury induced by CrVI was barely observed even after 60 min of incubation. (2) The CrVI-induced lipid peroxidation was inhibited by catalase and mannitol as scavengers of active oxygen species, or N,N'-diphenyl-p-phenylenediamine and alpha-tocopherol as antioxidants. However the cytotoxicity of CrVI could not be prevented by these chemicals. (3) CrVI depleted the contents of intracellular GSH and diminished the activities of glutathione reductase (GR) and glutathione-S-transferase (GST) except glutathione peroxidase. (4) The scavengers of active oxygen species and the antioxidants could not prevent the depletion of intracellular GSH induced by CrVI. (6) Ascorbic acid, antichromium agent, prevented all of the lipid peroxidation, the cellular injury and intracellular GSH depletion induced by CrVI.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
90.