全文获取类型
收费全文 | 79968篇 |
免费 | 4323篇 |
国内免费 | 48篇 |
专业分类
林业 | 3813篇 |
农学 | 2811篇 |
基础科学 | 481篇 |
10596篇 | |
综合类 | 9939篇 |
农作物 | 2912篇 |
水产渔业 | 4311篇 |
畜牧兽医 | 43870篇 |
园艺 | 962篇 |
植物保护 | 4644篇 |
出版年
2018年 | 1298篇 |
2017年 | 1451篇 |
2016年 | 1385篇 |
2015年 | 1131篇 |
2014年 | 1391篇 |
2013年 | 3160篇 |
2012年 | 2469篇 |
2011年 | 2980篇 |
2010年 | 2016篇 |
2009年 | 1949篇 |
2008年 | 2844篇 |
2007年 | 2806篇 |
2006年 | 2611篇 |
2005年 | 2389篇 |
2004年 | 2211篇 |
2003年 | 2231篇 |
2002年 | 2047篇 |
2001年 | 2953篇 |
2000年 | 2827篇 |
1999年 | 2248篇 |
1998年 | 918篇 |
1997年 | 865篇 |
1996年 | 787篇 |
1995年 | 891篇 |
1994年 | 770篇 |
1993年 | 764篇 |
1992年 | 1627篇 |
1991年 | 1847篇 |
1990年 | 1816篇 |
1989年 | 1677篇 |
1988年 | 1589篇 |
1987年 | 1585篇 |
1986年 | 1476篇 |
1985年 | 1436篇 |
1984年 | 1200篇 |
1983年 | 970篇 |
1982年 | 731篇 |
1979年 | 1124篇 |
1978年 | 876篇 |
1977年 | 720篇 |
1976年 | 793篇 |
1975年 | 783篇 |
1974年 | 927篇 |
1973年 | 874篇 |
1972年 | 888篇 |
1971年 | 815篇 |
1970年 | 778篇 |
1969年 | 795篇 |
1967年 | 791篇 |
1966年 | 729篇 |
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
11.
W W Chan K Y Chen H Liu L S Wu J H Lin 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2001,63(10):1057-1062
Since the International Society of Veterinary Acupuncture (IVAS) was founded in 1974, acupuncture (AP) has received greater acceptance by veterinary professionals throughout the world. This article introduces some important animal diseases that respond well to AP therapy. These include resuscitation of small animals, treatment of anoestrous gilts and sows, bovine reproductive disease, canine vertebral problems and equine backpain, etc. Conventional medicine considers these to be difficult cases to treat. Veterinarians have become more aware of the benefits of AP especially for those diseases, thanks to the efforts of experienced practitioners and scientists, and the many published reports on veterinary AP that have introduced some good indications for AP therapy in veterinary practice. Possible mechanisms behind the effectiveness of AP are discussed. This article aims to introduce veterinarians to good indications for AP to initiate their interest in the practice of AP. Although this is a rapidly expanding field, a long march must begin with one step. We wish this article to be the shoes for such a march. For more information on veterinary AP, contact IVAS , P.O. Box 1478, Longmont, CO.. 80502, USA (http://www.ivas.org), or your national veterinary acupuncture society (http://www.komvet.at/ ivadkom/vapsocs.htm). 相似文献
12.
13.
14.
T Sekizaki Y Nakasato I Nonomura 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1992,54(3):493-499
Chicken pathogenic Escherichia coli strains were found to autoagglutinate in a static culture of trypticase soy broth (TSB). One strain, designated PDI-386, was further studied for its autoagglutinating property. Acidity in the cultured medium caused by glucose degradation induced the autoagglutination. The bacterial cells grown in a glucose-free L-broth could be aggregated by adding acid, which suggests a potentiality of autoagglutination of the strain grown in the L-broth. The autoagglutinating parent (Agg) formed small colonies with irregular edges like rough colonies on the TS agar, whereas its non-autoagglutinating variant (Nag) formed larger smooth colonies with a perfectly round edge. The Nag colony was easily generated from the Agg colony on the TS agar. The autoagglutinating property was very unstable when the bacteria was passed in the TSB, but rather stable in the L-broth. Under electron microscope, the Agg were found to possess pili of more than 20 microns in length. However, the phenotypic expression of autoagglutination did not correlate with that of mannose-sensitive hemagglutination against guinea pig erythrocytes. Incubation of the Nag in the L-broth at room temperature for more than 10 days provoked the reversion of the autoagglutination. There was no difference between the Agg and the Nag in terms of surface hydrophobicity, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns of membrane proteins and LPS, and plasmid profiles. The virulence of the Agg was higher than that of the Nag. The autoagglutination property is, however, so unstable that the pathogenicity of E. coli isolates from chickens should be carefully evaluated. 相似文献
15.
29 samples of commonly used surfaces were tested for their water characteristics (litre weight, water capacity, water binding, water evaporation) and their contribution to airborne fungal spores (dust formation, dust setting). The results are discussed in comparison to the literature with regard to the environment. The results are: 1. Any surface--no matter of what material--eventually causes air pollution with fungal spores and dust. 2. Correct watering prevents air pollution by any surface. 3. Artificial products have no advantage over natural materials in the parameters tested. 4. The question of proper disposal of old surface material has to be clarified before purchase. The results show that a mixture of sand and wood shavings should be recommended as a surface for indoor arenas, especially in regard to environmental protection and proper disposal. 相似文献
16.
Abstract. In field and laboratory experiments the conditioner‘Agri-SC’has shown improvements in the structure of loamy sand soils in east Shropshire, UK. It resulted in statistically significant decreases in soil bulk density values and increases in soil porosity and aggregate stability. Further experiments are in progress on both loamy sand and silt loam soils. 相似文献
17.
The study describes plumage modifications and specific feather malformations, as related to the domestication process of different poultry species. The modifications include naked necks, leg feathering, frizzle feathering, silky feathering, fat quills, and feather abnormalities caused by behavioural hypertrophies. Most of these plumage modifications correspond to the breed standard for exhibition poultry fancy. However, they impair the normal function of these animals. The negative influences comprise disorders in social behaviour, loss of typical plumage functions and disabilities of normal mobility, as well as genetic defects and pathogenic predispositions. 相似文献
18.
Anthony S. Moore BVSc MVSc Gregory K. Ogilvie David M. Vail 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1994,8(5):343-344
Twenty-five dogs with malignant lymphoma refractory to chemotherapy were treated with actinomycin D at a median dose of 0.7 mg/m2 (range, 0.5 to 0.9 mg/m2 ) every 3 weeks. The dogs treated had received between 2 and 8 chemotherapeutic agents (median 7), for a median of 266 days before being treated with actinomycin D. For 23 of the 25 dogs, previous chemotherapy included doxorubicin. No dog responded to actinomycin D chemotherapy. 相似文献
19.
N Machida T Nakamura K Kiryu S Haramaki K Too 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1992,54(6):1213-1216
A 20-year-old pony mare with persistent ventricular tachycardia (VT) was examined cardiopathologically. At necropsy, the heart was enlarged and rounded with both ventricular dilatation. In a longitudinal section of the ventricular septum, a large grayish white patchy lesion (5 x 25 mm) was detected in the relatively higher portion. Microscopically, the lesion was extensive myocardial fibrosis located in the vicinity of the proximal part of the left bundle branch. Partially the fibrotic lesion was in contact with the branch. Such a lesion might play an important role in creating a suitable background for the development of VT via automaticity or reentry mechanism. 相似文献
20.
The use of phytotherapy to treat human diseases has its roots in pre-historical times. Despite the modern advances achieved in the field of synthetic chemistry, the most efficient drugs available have their genesis directly or indirectly related with the vegetal kingdom. Indigenous communities have long used plant extracts to treat illnesses. Many of these extracts have shown effective action, with new bioactive compounds being extracted and screened every year. These extracts have also proven to be good sources of therapeutic agents to the treatment of Leishmaniasis. This work highlights some of these agents, while trying to emphasize the importance of plants as a source of new and powerful drugs against this widespread disease. 相似文献