全文获取类型
收费全文 | 864篇 |
免费 | 41篇 |
专业分类
林业 | 146篇 |
农学 | 64篇 |
基础科学 | 5篇 |
95篇 | |
综合类 | 116篇 |
农作物 | 16篇 |
水产渔业 | 34篇 |
畜牧兽医 | 387篇 |
园艺 | 15篇 |
植物保护 | 27篇 |
出版年
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 11篇 |
2018年 | 15篇 |
2017年 | 21篇 |
2016年 | 13篇 |
2015年 | 18篇 |
2014年 | 18篇 |
2013年 | 31篇 |
2012年 | 39篇 |
2011年 | 36篇 |
2010年 | 15篇 |
2009年 | 25篇 |
2008年 | 35篇 |
2007年 | 33篇 |
2006年 | 30篇 |
2005年 | 25篇 |
2004年 | 19篇 |
2003年 | 35篇 |
2002年 | 23篇 |
2001年 | 27篇 |
2000年 | 28篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 8篇 |
1994年 | 9篇 |
1992年 | 12篇 |
1991年 | 15篇 |
1990年 | 10篇 |
1989年 | 20篇 |
1988年 | 18篇 |
1987年 | 11篇 |
1985年 | 10篇 |
1984年 | 9篇 |
1983年 | 11篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 10篇 |
1977年 | 14篇 |
1975年 | 8篇 |
1974年 | 10篇 |
1973年 | 6篇 |
1972年 | 11篇 |
1971年 | 9篇 |
1969年 | 8篇 |
1967年 | 8篇 |
1966年 | 14篇 |
1924年 | 5篇 |
1921年 | 9篇 |
排序方式: 共有905条查询结果,搜索用时 281 毫秒
31.
32.
Seguin BE Zhang TQ Buoen LC Weber AF Ruth GR 《Journal of the American Veterinary Medical Association》2000,216(1):65-67
OBJECTIVE: To determine prevalence of Holstein bulls with chromosomal anomalies, particularly the 1/21 centric fusion (CF), at a commercial artificial insemination (AI) company in the United States. DESIGN: Cross-sectional cytogenetic prevalence study. ANIMALS: All 606 Holstein bulls at a commercial AI company were cytogenetically screened to detect CF, chimerism, and other chromosomal abnormalities. PROCEDURE: Lymphocytes from heparinized blood samples were cultured by standard cytogenetic techniques, and chromosome spreads were prepared for microscopic examination. Chromosomal abnormalities were detected by examining 10 chromosome spreads per bull. Pedigree analysis was performed. RESULTS: None of the bulls had any type of CF. However, 6 bulls were identified as chimeras (i.e., contained lymphocytes with male [XY] and female [XX] chromosomes). One bull was sire or maternal grandsire to 85 of the bulls tested, and 739 of 1,212 (61%) sire and maternal-grandsire possibilities were accounted for by just 18 bulls. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of these results supports previous indications that CF is extremely rare in Holstein bloodlines available commercially via AI in the United States. However, chimeric bulls are more common, and they reportedly have decreased reproductive performance. Therefore, identification of chimeric sires in the AI facility reported here and the possibility of de novo onset of CF at any time indicates that early cytogenetic screening should be encouraged for prospective bulls intended for use in AI programs. 相似文献
33.
F. Tanno U. Weber Ch. Wacker L. Gaschen V. Schmid J. Lang 《The Journal of small animal practice》1998,39(9):432-436
Ultrasonography was used to compare adhesions induced by two different methods of gastropexy in 16 dogs. An incisional gastropexy technique was used in eight dogs (group 1) and a 'modified' gastropexy technique in the remaining eight (group 2). The length and thickness of the gastropexy and the peristaltic activity of the stomach were measured ultrasonographically and compared between groups. Measurements for the two groups were taken in the early postoperative interval (two to four days), intermediate postoperative interval (eight to 20 days) and late postoperative interval (57 to 79 days). Both techniques were equally successful in forming permanent adhesions at two months postoperatively and there was no recurrence of gastric dilatation and volvulus. The length and thickness of the gastropexy were similar for both groups at two months postoperatively and there were no surgical complications with either technique. The modified gastropexy provides a technique that can easily be performed by a single surgeon , with no increased operative time or duration of anaesthesia, and with the formation of a permanent adhesion. 相似文献
34.
ULTRASONOGRAPHIC DETECTION OF ADRENAL GLAND TUMOR AND URETEROLITHIASIS IN A GUINEA PIG 总被引:1,自引:0,他引:1
Lorrie Gaschen DVM Cornelia Ketz Dr. med. vet. Johann Lang Dr. med. vet Urs Weber Dr. med. vet. L. Bacciarini Dr. med. vet. Ingrid Kohler med. vet. 《Veterinary radiology & ultrasound》1998,39(1):43-46
A 5-year-old guinea pig was presented to the University of Berne Small Animal Radiology Department for an ultrasound examination of the abdomen to confirm a suspected diagnosis of Cushing's syndrome. The patient had bilateral alopecia, was apathic and obese. Ultrasonographically, a tumor of the left adrenal gland, obstruction of the left ureter by an ureterolith, as well as hydronephrosis of the left kidney were detected. During surgery to relieve the ureteral obstruction the adrenal gland tumor was removed. The guinea pig died post-operatively due to blood loss. The left adrenal gland tumor was found histopathologically to be an adenoma and the right adrenal gland also had multiple small adenomas, but grossly appeared normal. The ureterolith was analyzed and found by x-ray diffraction to consist of calcium carbonate. 相似文献
35.
Weber 《Forstwissenschaftliches Centralblatt》1904,26(11):621-629
Ohne Zusammenfassung 相似文献
36.
Heinrich Wilhelm Weber 《Forstwissenschaftliches Centralblatt》1922,44(6):214-224
Ohne Zusammenfassung 相似文献
37.
38.
T. Weber 《Journal of pest science》1964,37(4):59-60
Ohne Zusammenfassung 相似文献
39.
40.
Trutz Weber 《Journal of pest science》1965,38(2):26-26
Ohne ZusammenfassungHerrn Professor Dr. F. Schwerdtfeger zum 60. Geburtstag gewidmet. 相似文献