全文获取类型
收费全文 | 1714篇 |
免费 | 114篇 |
专业分类
林业 | 49篇 |
农学 | 15篇 |
基础科学 | 7篇 |
133篇 | |
综合类 | 354篇 |
农作物 | 55篇 |
水产渔业 | 34篇 |
畜牧兽医 | 1122篇 |
园艺 | 18篇 |
植物保护 | 41篇 |
出版年
2021年 | 15篇 |
2020年 | 33篇 |
2019年 | 26篇 |
2018年 | 28篇 |
2017年 | 28篇 |
2016年 | 25篇 |
2015年 | 16篇 |
2014年 | 30篇 |
2013年 | 65篇 |
2012年 | 60篇 |
2011年 | 68篇 |
2010年 | 43篇 |
2009年 | 43篇 |
2008年 | 61篇 |
2007年 | 76篇 |
2006年 | 76篇 |
2005年 | 68篇 |
2004年 | 63篇 |
2003年 | 75篇 |
2002年 | 61篇 |
2001年 | 43篇 |
2000年 | 53篇 |
1999年 | 32篇 |
1998年 | 23篇 |
1997年 | 18篇 |
1995年 | 19篇 |
1994年 | 18篇 |
1992年 | 42篇 |
1991年 | 42篇 |
1990年 | 37篇 |
1989年 | 36篇 |
1988年 | 29篇 |
1987年 | 24篇 |
1986年 | 32篇 |
1985年 | 20篇 |
1984年 | 14篇 |
1983年 | 16篇 |
1981年 | 11篇 |
1979年 | 15篇 |
1978年 | 9篇 |
1977年 | 11篇 |
1974年 | 16篇 |
1973年 | 11篇 |
1972年 | 10篇 |
1971年 | 10篇 |
1970年 | 14篇 |
1969年 | 21篇 |
1968年 | 12篇 |
1967年 | 11篇 |
1966年 | 18篇 |
排序方式: 共有1828条查询结果,搜索用时 19 毫秒
991.
Rassnick KM Gieger TL Williams LE Ruslander DM Northrup NC Kristal O Myers NC Moore AS 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2001,15(3):196-199
1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks. 相似文献
992.
Buss MS Henry CJ Tyler JW Tobias KS Daoud S Hoopes J Moore MP 《American journal of veterinary research》1999,60(3):280-283
OBJECTIVES: To determine systemic and local platinum concentrations released from subcutaneously implanted cis-diamminedichloroplatinum (cisplatin) -impregnated polymethylmethacrylate (PMMA) and to evaluate systemic or local adverse reactions. ANIMALS: 6 healthy dogs. PROCEDURE: Cisplatin (20 mg) was inserted into PMMA that was fashioned into cylinders and placed into subcutaneous tissue chambers overlying the thorax (treated site). An empty tissue chamber was placed over the opposite side (control site). Plasma samples were obtained for platinum determination before implantation, at 3, 6, and 12 hours after implantation on day 0, and once daily on days 1, 2, 3, 7, 14, 21, and 29. At similar times on similar days, tissue chamber fluid samples also were obtained for platinum determination. Complete blood count, serum urea nitrogen and creatinine concentration determinations, and urinalyses were performed on days 1, 2, 3, 7, 14, 21, and 29. Complete necropsy was performed at conclusion of the study. RESULTS: Tissue chamber platinum concentrations at the treated site were significantly greater than plasma and control site tissue chamber concentrations on days 2, 3, 7, 10. Mean plasma platinum concentration at 3 (0.735 microg/ml), 6 (0.691 microg/ml), 12 (0.534 microg/ml), 24 (0.131 microg/ml), 48 (0.2 microg/ml), 72 (0.1 microg/ml), and 158 (0.014 microg/ml) hours was significantly greater than pretreatment values (0.0 microg/ml). Plasma platinum concentration 10 days after treatment (0.011 microg/ml) did not significantly differ from pretreatment values. Local or systemic adverse reactions were not apparent. CONCLUSIONS: The route of cisplatin administration was safe. Greater concentration of platinum was released locally relative to plasma concentration for an extended period. 相似文献
993.
Bueno AC Cornick-Seahorn J Seahorn TL Hosgood G Moore RM 《American journal of veterinary research》1999,60(11):1371-1376
OBJECTIVE: To determine the cardiopulmonary and sedative effects of medetomidine hydrochloride in adult horses and to compare those effects with effects of an equipotent dose of xylazine hydrochloride. ANIMALS: 10 healthy adult female horses. PROCEDURE: 5 horses were given medetomidine (4 microg/kg of body weight, i.v.), and the other 5 were given xylazine (0.4 mg/kg, i.v.). Heart rate, respiratory rate, arterial blood pressures, pulmonary arterial blood pressures, and cardiac output were recorded, and sedation and ataxia scores were assigned before and every 5 minutes after drug administration for 60 minutes. Rectal temperature and blood gas partial pressures were measured every 15 minutes after drug administration. RESULTS: Arterial blood pressure was significantly decreased throughout the study among horses given medetomidine and was significantly decreased for 40 minutes among horses given xylazine. Compared with baseline values, cardiac output was significantly decreased 10, 20, and 40 minutes after administration of medetomidine and significantly increased 40 and 60 minutes after administration of xylazine. Despite the significant decrease in respiratory rate in both groups, results of blood gas analyses were not significantly changed over time. Ataxia and sedation scores were of similar magnitude for the 2 groups, but ataxia persisted slightly longer among horses given medetomidine. Horses resumed eating hay 10 to 55 minutes after drug administration. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that equipotent low doses of medetomidine and xylazine induce comparable levels of ataxia and sedation and similar cardiopulmonary changes in adult horses. 相似文献
994.
Morphologic features and S-100 protein immunoreactivity of a benign and malignant peripheral nerve sheath tumor were studied in two Wistar rats. Neoplasms that developed in untreated control rats from tumor bioassays were S-100 protein positive and had similar histopathologic features. Each peripheral nerve sheath tumor was encapsulated and composed of spindle cells arranged around small thin-walled blood vessels. Palisaded tumor cells were in the benign peripheral nerve sheath tumor while cells of the malignant peripheral nerve sheath tumor had cellular atypia and moderate numbers of mitoses. Ultrastructural examination of the malignant peripheral nerve sheath tumor revealed cells with external lamina and interdigitation of cytoplasmic processes. Intracytoplasmic concentric lamellae were seen; they were regularly spaced with a periodicity of about 15 nm. Such structures, indistinguishable from myelin sheaths, have not been commonly associated with peripheral nerve sheath tumors in man. Electron microscopy and immunohistochemistry were useful in the diagnosis of these tumors as Schwannomas and in differentiation from other spindle cell tumors. 相似文献
995.
Epizootiology, diagnosis, and control of Brucella canis 总被引:1,自引:0,他引:1
996.
Peripheral lymph node enlargement was found in 14 of a series of 132 feline lymph node biopsy specimens. Six of nine cats tested had antibodies for feline leukemia virus (FeLV). Half of the cats were clinically normal while the remainder had fever, lethargy, anorexia, and hepatosplenomegaly. There was severe distortion of lymph nodal architecture with variable loss of discernible follicles and sinuses. Histiocytes, lymphocytes, immunoblasts, and plasma cells were present in expanded paracortical regions which encroached on, and occasionally effaced, lymphoid follicles. Postcapillary venules were numerous and prominent throughout the paracortex. The lymphadenopathy was most commonly transient (86% of cases) with subsequent development of lymphoma in one cat. Lymph nodes from seven kittens with experimental FeLV infection were compared with spontaneously enlarged lymph nodes; four of seven had B and T lymphocyte hyperplasia with normal nodal architecture. Three had partial loss of nodal architecture as a result of expanded paracortical regions populated largely by histiocytes and lymphocytes. Proliferation of postcapillary venules was not prominent in nodes from FeLV-infected cats. The cause of spontaneous lymph node hyperplasia of young cats was not determined. However, the similarity of lesions to those of kittens with experimental FeLV infection and the association with FeLV by serologic tests in six of nine cats suggest that this retrovirus may be involved in the pathogenesis of the lesion. 相似文献
997.
Changes in leukocyte populations in pulmonary lavage fluids of calves after inhalation of Pasteurella haemolytica 总被引:7,自引:0,他引:7
R D Walker F M Hopkins T W Schultz M D McCracken R N Moore 《American journal of veterinary research》1985,46(12):2429-2433
The distribution of leukocytes in bovine bronchoalveolar lavage fluids was determined in 15 calves at various times after aerosol exposure to Pasteurella haemolytica. For comparison, 10 calves were exposed to aerosols of phosphate-buffered saline solution; 15 calves, to Staphylococcus epidermidis; and 10 calves, to Salmonella typhimurium endotoxin. At 10 minutes after inhalation exposure for each group, the predominant cell type was the macrophage. Macrophages remained the predominant cell type throughout each lavage interval for calves exposed to phosphate-buffered saline solution and Staph epidermidis. For calves exposed to P haemolytica, there was a decrease in the percentage of macrophages detectable by 30 minutes after exposure, with a corresponding increase in the percentage of neutrophils. Sixty minutes after the inhalation exposure to P haemolytica, the percentages of macrophages and neutrophils in the lavage fluid were equal. By 240 minutes after exposure to P haemolytica, greater than 90% of the cells in the lavage fluids was neutrophils. The increase in the percentage of neutrophils in lavage fluids from calves exposed to S typhimurium endotoxin was similar to that seen for the calves exposed to P haemolytica. 相似文献
998.
999.
Antileukotoxin antibody produced in the bovine lung after aerosol exposure to viable Pasteurella haemolytica 总被引:6,自引:0,他引:6
R N Moore R D Walker G A Shaw F M Hopkins E P Shull 《American journal of veterinary research》1985,46(9):1949-1952
Experiments were performed to determine the in vivo immunogenicity of Pasteurella haemolytica leukotoxin. Calves were exposed twice to aerosol mists of viable P haemolytica, using a treatment regimen previously shown to induce a resistant state. Pulmonary lavage fluids and serum samples from these calves were assayed for leukotoxin-neutralizing antibodies. Before aerosol exposure, neutralizing antibody titers were routinely found in serum samples, but were not detectable in pulmonary lavage concentrates before exposure. After aerosol exposure, titers of toxin-neutralizing immunoglobulin (Ig)A and IgG antibodies were found in pulmonary lavage concentrates and were accompanied by increased serum toxin neutralization titers. 相似文献