全文获取类型
收费全文 | 105894篇 |
免费 | 5554篇 |
国内免费 | 52篇 |
专业分类
林业 | 4320篇 |
农学 | 3046篇 |
基础科学 | 730篇 |
11743篇 | |
综合类 | 20815篇 |
农作物 | 4302篇 |
水产渔业 | 4648篇 |
畜牧兽医 | 54539篇 |
园艺 | 1205篇 |
植物保护 | 6152篇 |
出版年
2018年 | 1210篇 |
2017年 | 1336篇 |
2016年 | 1298篇 |
2015年 | 1100篇 |
2014年 | 1270篇 |
2013年 | 3951篇 |
2012年 | 2582篇 |
2011年 | 3206篇 |
2010年 | 2094篇 |
2009年 | 2058篇 |
2008年 | 3214篇 |
2007年 | 2960篇 |
2006年 | 2817篇 |
2005年 | 2651篇 |
2004年 | 2762篇 |
2003年 | 2693篇 |
2002年 | 2633篇 |
2001年 | 3280篇 |
2000年 | 3302篇 |
1999年 | 2452篇 |
1998年 | 1073篇 |
1997年 | 1083篇 |
1995年 | 1258篇 |
1994年 | 1168篇 |
1993年 | 1122篇 |
1992年 | 2370篇 |
1991年 | 2537篇 |
1990年 | 2447篇 |
1989年 | 2495篇 |
1988年 | 2281篇 |
1987年 | 2356篇 |
1986年 | 2493篇 |
1985年 | 2400篇 |
1984年 | 1922篇 |
1983年 | 1775篇 |
1982年 | 1168篇 |
1981年 | 1124篇 |
1980年 | 1027篇 |
1979年 | 1764篇 |
1978年 | 1425篇 |
1977年 | 1147篇 |
1976年 | 1132篇 |
1975年 | 1168篇 |
1974年 | 1528篇 |
1973年 | 1615篇 |
1972年 | 1595篇 |
1971年 | 1526篇 |
1970年 | 1413篇 |
1969年 | 1266篇 |
1967年 | 1096篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
43.
44.
45.
46.
47.
48.
Disseminated Aspergillus terreus infection was diagnosed in ten previously healthy adult dogs--nine German shepherds and one dalmatian. The disease was characterized by the presence of multiple granulomas and infarcts in a wide range of organs. The kidney, spleen, and skeletal system were most commonly and severely affected. Fungal hyphae were demonstrated in large numbers within granulomas and thrombi, and A. terreus was readily isolated by culture. This disseminated mycosis appears unique; in this series of cases there was no apparent predisposing factor, portal of entry, or primary focus for dissemination of the infection. 相似文献
49.
M P Yang R Goitsuka H Tsujimoto M Onuma A Hasegawa 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1992,54(4):757-761
The association of tumor-associated antigen (TAA) on the proliferation of BLV-infected lymphoblastoid B-cell lines (BL2M3 and BL312) was investigated. Flow cytometric analysis of the expression of TAA with monoclonal antibody (mAb) c143 showed high expression of TAA on the surfaces of BL2M3 and BL312 cells. A large amount of TAA was found in the culture supernatant of BL2M3 and BL312 cells as well as in the lysates of BL2M3 and BL312 cells. Culture supernatant but not lysates of BL2M3 and BL312 cells promoted the growth of either BL2M3 cells or BL312 cells. Furthermore, this growth promoting activity in culture supernatants of BL2M3 and BL312 cells was inhibited in a dose-dependent manner when cultured with mAb c143. These results suggested that TAA may be involved in the growth factor-mediated cell growth of bovine B-lymphoblastoid cell lines expressing TAA on their cell surface. 相似文献
50.
Estrogen and progesterone receptor status of mammary carcinomas and correlation with clinical outcome in dogs. 总被引:3,自引:0,他引:3
E A Sartin S Barnes R P Kwapien L G Wolfe 《American journal of veterinary research》1992,53(11):2196-2200
Estrogen and progesterone receptors (ER, PR) were measured in cytosol fractions from 18 primary canine mammary carcinomas by use of biochemical assays. One or both receptors were detected (> 10 fmol/mg of cytosol protein) in 11 tumors: 5 ER and PR; 2 ER only; 4 PR only. Mean cytoplasmic receptor concentrations (fmol/mg of cytosol protein) were 22.8 +/- 2.9 (SEM) for ER and 51.0 +/- 10.3 for PR in tumors containing ER and PR, 28.8 +/- 12.1 for ER in tumors containing only ER and 13.2 +/- 1.5 for PR in tumors containing only PR. Estrogen or progesterone receptors or both were identified in 6 of 9 tubular adenocarcinomas, 4 of 5 papillary adenocarcinomas, and 1 of 1 squamous cell carcinoma. These receptors were not identified in solid carcinomas (n = 2) or a single spindle cell carcinoma. Although the number of cases was limited, survival times of dogs tended to be longest in those with tumors containing ER alone or in combination with PR, intermediate in those with tumors containing only PR, and shortest in those with tumors without ER or PR. A correlation was not apparent between receptor status and age, presence of ovaries, tumor size, or histologic classification of the tumor. In the analysis of this series, the extent of surgery (mastectomy of the involved gland vs unilateral or bilateral mastectomy) did not appear to influence the outcome of the disease, and metastasis to regional lymph nodes did not appear to be a reliable prognostic indicator. 相似文献