全文获取类型
收费全文 | 73284篇 |
免费 | 4132篇 |
国内免费 | 32篇 |
专业分类
林业 | 3175篇 |
农学 | 2397篇 |
基础科学 | 466篇 |
8669篇 | |
综合类 | 12016篇 |
农作物 | 2818篇 |
水产渔业 | 3522篇 |
畜牧兽医 | 38582篇 |
园艺 | 835篇 |
植物保护 | 4968篇 |
出版年
2018年 | 966篇 |
2017年 | 1073篇 |
2016年 | 1000篇 |
2015年 | 845篇 |
2014年 | 1046篇 |
2013年 | 2745篇 |
2012年 | 1943篇 |
2011年 | 2268篇 |
2010年 | 1534篇 |
2009年 | 1558篇 |
2008年 | 2321篇 |
2007年 | 2220篇 |
2006年 | 2035篇 |
2005年 | 1969篇 |
2004年 | 1846篇 |
2003年 | 1989篇 |
2002年 | 1806篇 |
2001年 | 2239篇 |
2000年 | 2190篇 |
1999年 | 1748篇 |
1998年 | 714篇 |
1997年 | 776篇 |
1996年 | 685篇 |
1995年 | 865篇 |
1994年 | 734篇 |
1993年 | 734篇 |
1992年 | 1493篇 |
1991年 | 1634篇 |
1990年 | 1602篇 |
1989年 | 1606篇 |
1988年 | 1493篇 |
1987年 | 1456篇 |
1986年 | 1536篇 |
1985年 | 1449篇 |
1984年 | 1270篇 |
1983年 | 1063篇 |
1982年 | 748篇 |
1979年 | 1171篇 |
1978年 | 887篇 |
1977年 | 840篇 |
1976年 | 799篇 |
1975年 | 829篇 |
1974年 | 1030篇 |
1973年 | 1070篇 |
1972年 | 1018篇 |
1971年 | 951篇 |
1970年 | 927篇 |
1969年 | 899篇 |
1968年 | 754篇 |
1967年 | 844篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
Ginder GD 《Science (New York, N.Y.)》1985,228(4701):865-866
122.
123.
124.
Straus LG 《Science (New York, N.Y.)》1985,230(4725):501-507
The Vasco-Cantabrian region of Spain is one of the few areas of the world where a large sample of archeological sites has yielded a detailed record of the changes in the human condition in the period spanning Neanderthal times from about 125,000 years ago until the adoption of food production, less than 6000 years ago in this area. During this time, human adaptations underwent a series of crucial transformations involving profound changes in cultural systems and perthaps also in aspects of the biological basis for culture. 相似文献
125.
126.
127.
128.
Wobeser G Gajadhar AA Hunt HM 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(8):241-244
Infection with Fascioloides magna, the large American liver fluke, was diagnosed in two moose (Alces alces) and six wapiti (Cervus elaphus) from central Saskatchewan. This is believed to be the first record of the parasite in the province. Fecal samples collected from wild wapiti at five sites in the commercial forest zone in Saskatchewan contained eggs believed to be those of F. magna. Trematode eggs were not found in feces from five captive herds of wapiti in the province, nor in samples from wild wapiti in Moose Mountain Provincial Park. Operculate eggs were found in feces of wild wapiti from Cypress Hills, but these were believed to be from trematodes other than F. magna. The distribution and significance of F. magna in Canada, based partially on responses to a mail questionnaire, are reviewed. 相似文献
129.
Harasen GL 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(6):193-194
Two cases of noninfectious, nonerosive arthritis are presented. The diagnostic features, clinical course and treatment are reviewed. Potential etiologies are discussed in the light of relatively little current material on this subject in the veterinary literature. 相似文献
130.
Blue MG 《New Zealand veterinary journal》1985,33(1-2):17-19
A developmental anomaly, resulting from partial segmental aplasia of the Mullerian ducts, was present in a Clydesdale mare. She had complete double cervices and a divided uterine body. In this mare, bilateral pregnancies were destroyed in sequence by squeezing them per rectum 25 and 29 days after insemination. 相似文献