全文获取类型
收费全文 | 78780篇 |
免费 | 4246篇 |
国内免费 | 93篇 |
专业分类
林业 | 3184篇 |
农学 | 2042篇 |
基础科学 | 461篇 |
8557篇 | |
综合类 | 15393篇 |
农作物 | 3124篇 |
水产渔业 | 3414篇 |
畜牧兽医 | 41661篇 |
园艺 | 844篇 |
植物保护 | 4439篇 |
出版年
2019年 | 718篇 |
2018年 | 1091篇 |
2017年 | 1211篇 |
2016年 | 1046篇 |
2015年 | 902篇 |
2014年 | 1188篇 |
2013年 | 2618篇 |
2012年 | 2111篇 |
2011年 | 2570篇 |
2010年 | 1614篇 |
2009年 | 1726篇 |
2008年 | 2592篇 |
2007年 | 2402篇 |
2006年 | 2282篇 |
2005年 | 2133篇 |
2004年 | 2075篇 |
2003年 | 2134篇 |
2002年 | 1921篇 |
2001年 | 2384篇 |
2000年 | 2438篇 |
1999年 | 1868篇 |
1998年 | 719篇 |
1997年 | 711篇 |
1996年 | 711篇 |
1995年 | 805篇 |
1993年 | 740篇 |
1992年 | 1553篇 |
1991年 | 1750篇 |
1990年 | 1634篇 |
1989年 | 1646篇 |
1988年 | 1472篇 |
1987年 | 1534篇 |
1986年 | 1596篇 |
1985年 | 1547篇 |
1984年 | 1184篇 |
1983年 | 1057篇 |
1982年 | 704篇 |
1979年 | 1152篇 |
1978年 | 894篇 |
1977年 | 755篇 |
1975年 | 774篇 |
1974年 | 1024篇 |
1973年 | 1024篇 |
1972年 | 1043篇 |
1971年 | 993篇 |
1970年 | 987篇 |
1969年 | 903篇 |
1968年 | 810篇 |
1967年 | 799篇 |
1966年 | 732篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
221.
Eighty-nine cats and 38 dogs naturally infested with the ear mite Otodectes cynotis were randomly allocated into two treatment groups. One group was treated with a product containing miconazole nitrate, polymyxin B sulphate and prednisolone acetate, the other with a combination of diethanolamine fusidate, framycetin sulphate, nystatin and prednisolone. The treatment (five drops in each ear) was applied twice daily for 14 days, and its efficacy was evaluated on days 7, 14 and 21 on the basis of an otoscopic examination of the external ear canal, a microscopical examination of scrapings for the presence of ear mites and clinical signs of pruritus, pain, erythema and/or exudate. Both treatments were highly effective, and there were no significant differences between the two products, either in efficacy or in the clinical improvements observed. Apart from an allergic reaction in one cat treated with the second product, no adverse effects were observed. 相似文献
222.
Swaim SF Gillette RL Sartin EA Hinkle SH Coolman SL 《American journal of veterinary research》2000,61(12):1574-1578
OBJECTIVE: To determine the effects of a hydrolyzed bovine collagen dressing (HBCD) on healing of open wounds in healthy dogs. ANIMALS: 9 female Beagles. PROCEDURES: 2 full-thickness skin wounds were made bilaterally on the trunk of each dog. Wounds on 1 side were treated with powdered HBCD covered with a semiocclusive nonadherent bandage. Wounds on the other side (control wounds) were covered with a semiocclusive nonadherent bandage only. Wound healing was subjectively assessed, and percentage increase in tissue perfusion was assessed by use of laser Doppler perfusion imaging (LDPI). Planimetry was performed to determine the percentages of contraction, epithelialization, and total wound healing. Biopsy specimens were examined microscopically to evaluate histologic changes. RESULTS: The HBCD did not induce a strong inflammatory reaction, as reflected by results of LDPI and histologic examination. Moreover, HBCD appeared hydrophilic and provided an environment to keep wounds clean and enhance early epithelialization. After treatment for 7 days, treated wounds had a significantly greater percentage of epithelialization than control wounds (12.13 vs. 7.03%). CONCLUSION AND CLINICAL RELEVANCE: The hydrophilic property of HBCD may cleanse contaminated wounds with the body's homeostatic fluids and enhance early wound epithelialization. 相似文献
223.
M M Otremba M E Dikeman G A Milliken S L Stroda J A Unruh E Chambers 《Journal of animal science》1999,77(4):865-873
224.
Immunoblot analysis of calpastatin degradation: evidence for cleavage by calpain in postmortem muscle. 总被引:6,自引:0,他引:6
A negative correlation exists between calpastatin activity and meat tenderness. Therefore, it is important to determine the mechanism of calpastatin inactivation in postmortem skeletal muscle. Western immunoblot analysis was performed to determine the protease(s) responsible for degradation of muscle calpastatin during postmortem storage. To accomplish this, purified calpastatin was digested with different proteases in vitro, and their pattern of calpastatin degradation was compared with that of calpastatin degradation in postmortem muscle. Polyclonal antibodies raised in mice against recombinant bovine skeletal muscle calpastatin were used to monitor calpastatin degradation. Lamb longissimus was stored at 4 degrees C and sampled at 0, 6, 12, 24, 72, 168, and 336 h postmortem. Postmortem storage produced a discrete pattern of calpastatin degradation products that included immunoreactive bands at approximately 100, 80, 65, 54, 32, and 29 kDa. Undegraded calpastatin (130 kDa) was barely detectable after 72 h of postmortem storage at 4 degrees C, and no immunoreactive calpastatin was observed by 336 h postmortem. For in vitro proteolysis, lamb longissimus calpastatin (0 h postmortem) was purified using Affi-Gel Blue chromatography. Calpastatin was digested with m-calpain, mu-calpain, cathepsin B, proteasome, trypsin, or chymotrypsin. Each of these enzymes degraded calpastatin. Immunoreactive fragments resulting from digestion of calpastatin with m- and mu-calpain were similar to each other and closely resembled those observed during postmortem aging of lamb longissimus at 4 degrees C. Digestion of calpastatin with mu-calpain reduced calpastatin activity. Degradation of calpastatin by other proteases resulted in unique patterns of immunoreactive fragments, distinct from that observed in longissimus. Thus, m- and(or) mu-calpain seem to be responsible for calpastatin degradation during postmortem storage of meat. 相似文献
225.
Duration of anesthesia onset (time to intubation) and recovery (time to extubation, sternal and standing) and quality of recovery were compared for sevoflurane and isoflurane in 10 adult psittacines. Both agents were initially administered at an equal volume percentage (2%) rather than at equal minimum alveolar concentrations (MACs), therefore the initial concentration was above the isoflurane MAC for dogs and birds (1.3%) but below the sevoflurane MAC for dogs (2.3%). The time to intubation was significantly longer with sevoflurane because of initially delivering the sevoflurane below suspected MAC for birds. Although recovery times (time to extubation, sternal, and standing) were not significantly different, birds recovering from sevoflurane were less ataxic. Sevoflurane is a suitable inhalant agent for use in these psittacines and merits further study. 相似文献
226.
Penzhorn BL Lewis BD López-Rebollar LM Swan GE 《Journal of the South African Veterinary Association》2000,71(1):53-57
The efficacy of 5 drugs was tested against experimental Babesia felis infection in domestic cats. Two of the drugs, rifampicin and a sulphadiazine-trimethoprim combination, appeared to have an anti-parasitic effect, but were inferior to primaquine. The other 3 drugs, buparvaquone, enrofloxacin and danofloxacin, had no significant anti-babesial effect. 相似文献
227.
228.
229.
W. Lilenbaum J. C. Schettini G. N. Souza E. R. Ribeiro E. C. Moreira L. S. Fonseca 《Zoonoses and public health》1999,46(5):353-358
Bovine tuberculosis is a major problem in Brazil. The intradermal tuberculin test is the standard test for detection of bovine tuberculosis in Brazil but can lack both sensitivity and specificity. The purpose of this study was to compare a bovine γ-IFN assay with the tuberculin test under field conditions in Brazil. A total of 1632 animals from 13 dairy farms were tested using the single cervical tuberculin test (SCTT). Among those animals, about 15% of each herd, 220 in total, represented a high-risk group and were selected to be tested using the γ-IFN test. Of the 1632 animals tested, 207 presented significant reactions representing 12.7% of the cattle studied. In the selected group the number of animals positive by the γ-IFN assay was 126/220 (57.3%) and the total number of reactive cows on SCTT was 106/220 (48.2%). The real number of infected cattle, following standards, was 120/220 (54.5%). From these results the relative sensitivity rate of γ-IFN test was 100% including the false-positive results and 88.3% for the SCTT — a significant (P < 0.01) difference in favour of the γ-IFN test of 11.7%. The γ-IFN assay also identified some positive animals 60–120 days earlier than the SCTT. In conclusion, we believe that the γ-IFN assay can be used alone or in combination with the SCTT, as a valuable tool for the control of bovine tuberculosis in the Brazilian national herd. 相似文献
230.