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291.
Rabies is a zoonotic disease caused by the rabies virus. While the salivary glands are important as exit and propagation sites for the rabies virus, the mechanisms of rabies excretion remain unclear. Here, we investigated the histopathology of the salivary glands of rabid dogs and analyzed the mechanism of excretion into the oral cavity. Mandibular and parotid glands of 22 rabid dogs and three control dogs were used. Mild to moderate non-suppurative sialadenitis was observed in the mandibular glands of 19 of the 22 dogs, characterized by loss of acinar epithelium and infiltration by lymphoplasmacytic cells. Viral antigens were detected in the mucous acinar epithelium, ganglion neurons and myoepithelium. Acinar epithelium and lymphocytes were positive for anti-caspase-3 antibodies and TUNEL staining. In contrast, no notable findings were observed in the ductal epithelial cells and serous demilune. In the parotid gland, the acinar cells, myoepithelium and ductal epithelium all tested negative. These findings confirmed the path through which the rabies virus descends along the facial nerve after proliferation in the brain to reach the ganglion neurons of the mandibular gland, subsequently traveling to the acinar epithelium via the salivary gland myoepithelium. Furthermore, the observation that nerve endings passing through the myoepithelium were absent from the ductal system suggested that viral proliferation and cytotoxicity could not occur there, ensuring that secretions containing the virus are efficiently excreted into the oral cavity.  相似文献   
292.
The effects on agonistic interactions of installing a tire in a pen with 24 weanling pigs allocated to six pens, with four animals in each, were determined. At the first grouping, two pigs were transferred from each pen to another pen where non‐littermates existed. Then half of the pens were equipped with a tire (Grouping 1). After one week, the pigs transferred at Grouping 1 were again transferred to other pens were non‐littermates existed (Grouping 2). At Grouping 2, any pen was not newly equipped with a tire and no pig was exposed to a tire for the first time. After another week, the pigs transferred at the previous groupings were once more transferred to other pens where non‐littermates existed (Grouping 3). At Grouping 3, the pigs in the pens with a tire were transferred to pens without a tire, and the pigs in the pens without a tire were transferred to pens with a tire. Then all pens were equipped with a tire. In Grouping 1, the effects on agonistic interactions of installing a tire were not significant. However, the injury score (less the score, less the number and damage of injury) was higher in the pens without a tire than in the pens with a tire (P < 0.05). In Grouping 2, pigs in the pens with a tire were attacked more than pigs in the pens without a tire (P < 0.05). The number of agonistic behaviors positively correlated with access to the tire (rs = 0.31; P < 0.01). In Grouping 3, the number of attacks received by pigs with no experience in using a tire was larger on the first day after grouping than on the 4th day (P < 0.05). The injury score was higher for pigs being transferred than for pigs not being transferred (P < 0.05). In conclusion: (i) installing a tire in a pen did not reduce the agonistic interactions of pigs, but it could change the style of their attacks, and (ii) initially having pigs experienced in using a tire can be useful for reducing the damage caused by agonistic interactions.  相似文献   
293.
To examine the tumor modification activity of kojic acid (KA) by sodium ascorbic acid (AA), 5-week-old male ICR mice were administered intraperitoneally with N-diethylnitrosamine (DEN) as an initiation treatment. Two weeks after the initiation treatment, animals were fed basal diet containing 0 (Group 1: DEN alone) or 3% KA (Group 3: DEN+KA), drinking water containing 5,000 ppm AA (Group 2: DEN+AA) or 3% KA and 5,000 ppm AA (Group 4: DEN+KA+AA) for 6 weeks. One week after the administration of KA and/or AA, all mice were subjected to two-thirds partial hepatectomy. At the end of the experimental period, all surviving mice were sacrificed and removed the liver. The liver weights of the Groups 3 and 4 were significantly increased, and the number of proliferating cell nuclear antigen positive hepatocytes and the gene expressions of Ccnc, Ccnd1, Ercc and Cyp7a1 were significantly increased in the Group 4, as compared to the Group 1. These results of the present study suggest that AA enhances the hepatocellular proliferative activity of KA in mice.  相似文献   
294.
295.
Dourine, caused by infection with Trypanosoma equiperdum, is one of the trypanosomiasis in equids. The clinical course of dourine is long-term, ranging from 1–2 months to several years. Since the pathogenesis of dourine has not yet been elucidated, experimental studies using mouse infection models are needed. Although mice are not susceptible to most T. equiperdum strains, some strains can infect mice. Even in such strains, infected mice develop rapidly transient parasitemia and die within 2–8 days. Therefore, mice experimentally infected with these T. equiperdum strains are not suitable for mouse infection models to analysis the pathogenesis of dourine. A sequential method of isolating parasites from dourine-affected horses and adapting them to in vitro cultures using soft agarose media was recently developed. Various T. equiperdum strains adapted to in vitro conditions have been established using this technique. We used one of these strains, the T. equiperdum IVM-t2 strain. In the present study, T. equiperdum IVM-t2 strain inoculated mice developed periodic parasitemia during the experimental period of 60 days. Histopathologically, vaginitis and dermatitis were observed. These findings were comparable to those of dourine-affected horses. Therefore, mice infected with T. equiperdum IVM-t2 strain may be a valuable tool for pathological, immunological, and parasitological in vivo research, and will contribute to investigations on the mechanisms underlying the disease process and the host-parasite relationship.  相似文献   
296.
To understand the viscoelasticity of wood three dimensionally, a longitudinal tensile creep test for 12 species was conducted to examine the changes with time in the lateral strain and the viscoelastic, i.e., apparent Poisson’s ratio. The changes in the lateral strain (ɛ T and ɛ R) were similar to those in the longitudinal strain (ɛ L). That is, during creep, the absolute value of lateral strain continued to increase with the gradual reduction in the increase rate; immediately after the removal of the load, it recovered abruptly; then, it recovered slowly and finally reached a certain value. The rate of increase in the longitudinal strain during creep was smaller than that in the absolute value of lateral strains. The apparent Poisson’s ratio became large during creep because the lateral strain increased more than the longitudinal strain. The analysis of lateral strain by decomposition into three components, that is, instantaneous strain, delayed elastic strain, and permanent strain, has revealed that the lateral permanent strain in the transverse direction contributes most to the increase in the apparent Poisson’s ratio during creep.  相似文献   
297.
298.
Twelve basic taxoids and 22 neutral taxoids were isolated from basic and polar neutral fractions of the extracts of needles and twigs of Taxus cuspidata. Among them, taxine NA-13, 3,11-cyclotaxinine NN-1, taxinine NN-6, 11(15→1)abeo-taxinine NN-1, taxine NA-8, and taxine NA-4 were isolated first from natural sources by us. The cytotoxic activity of isolated compounds was evaluated against three human cell lines: normal human fibroblast cells (WI-38), malignant tumor cells induced from WI-38 (VA-13), and human liver tumor cells (HepG2). 7-Epitaxol, 7-epicephalomannine, taxinine NN-6, taxine NA-2, taxuspine H, and taxagifine were active toward VA-13 cells and 7-epitaxol, 7-epicephalomannine, taxinine NN-1, 9,10-deacetyltaxinine, and taxagifine were active toward HepG2 cells. The multidrug-resistant (MDR) cancer reversal activity of isolated compounds was evaluated on the basis of the amount of vincristine (VCR) accumulated in MDR human ovarian cancer 2780 AD. Taxine NA-8, taxine NA-2, 5-cinnamoyl-10-acetyltaxicin II, and taxinine NN-1 indicated stronger MDR cancer reversal activity than verapamil. The result of primary screening based on 39 human cancer cell lines suggests that taxinine NN-1 belongs to a new mechanistic class and is a new anticancer agents. 7-Epicephalomannine was found to be an effective anticancer agent with tubulin as its molecular target, which is the same as paclitaxel. Part of this work was presented at the 74th Annual Meeting of the Chemical Society of Japan, Tanabe, March 1998, and the 41st Symposium on the Chemistry of Terpenes, Essential Oils, and Aromatics, Gifu, December 1998. The results of this work were also presented as patent documents at PCT Int: Appl WO 2001007040 A1, February 2001; Appl WO 2000-Jp 5036, 27 July 2000. Priority: JP 1999-214273, 28 July 1999; JP 1999-224652, 6 August 1999; JP 2000-76404, 14 March 2000  相似文献   
299.
以大花蕙兰(Cymbidium hookerianum)为试材,在外施CO_2条件下使用CP培养容器,比较不同光照度(14.4,30.6,54.0 μmol·m~(-2)·s~(-1))对大花蕙兰试管苗生长和叶片气孔特征的影响.结果显示,改善CP容器内CO_2浓度水平后,提高光照度可明显促进大花蕙兰试管苗的生长.高光照度(54.0 μmol·m~(-2)·s~(-1))下培养的试管苗与标准光照度(30.6 μmol·m~(-2)·s~(-1))相比,气孔密度虽较低,但其形态指标、叶绿素指数、气孔器大小和面积等重要测定指标却有明显提高;与低光照度(14.4 μmol·m~(-2)·s~(-1))相比,高光照度下培养的试管苗除株高、叶数、根长和气孔密度外,其它重要指标也均有明显提高,表明外施CO_2条件下高光照度对促进大花蕙兰试管苗的生长和提高其品质效果明显.  相似文献   
300.
In order to determine the population dynamics of juvenile Apostichopus japonicus, successive surveys were conducted in the stony intertidal zone of Hirao Bay, Seto Inland Sea. The juveniles of the green and black types of this species grew well from January to June. Before this high growing season, zero year old juveniles were too small to be readily detected by visual observations during field surveys. During the high water temperature season from August to November, juveniles over 1 year of age estivated underneath rocks. They awakened from their estivation in November, and it took another month before they could eat and discharge. The juveniles mainly migrated from the intertidal zone before they reached 3 years of age. In the present work, three patterns of juvenile growth were found. It is suggested that these differences in juvenile growth are mainly caused by differences in their start times for growth initiation when they are zero years old.  相似文献   
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