全文获取类型
收费全文 | 170408篇 |
免费 | 9366篇 |
国内免费 | 93篇 |
专业分类
林业 | 7200篇 |
农学 | 5625篇 |
基础科学 | 1177篇 |
20247篇 | |
综合类 | 30580篇 |
农作物 | 6689篇 |
水产渔业 | 8397篇 |
畜牧兽医 | 87580篇 |
园艺 | 2136篇 |
植物保护 | 10236篇 |
出版年
2018年 | 2343篇 |
2017年 | 2693篇 |
2016年 | 2512篇 |
2015年 | 2132篇 |
2014年 | 2543篇 |
2013年 | 6552篇 |
2012年 | 4670篇 |
2011年 | 5766篇 |
2010年 | 3853篇 |
2009年 | 3778篇 |
2008年 | 5738篇 |
2007年 | 5291篇 |
2006年 | 5103篇 |
2005年 | 4586篇 |
2004年 | 4578篇 |
2003年 | 4546篇 |
2002年 | 4329篇 |
2001年 | 5633篇 |
2000年 | 5525篇 |
1999年 | 4242篇 |
1998年 | 1769篇 |
1997年 | 1830篇 |
1996年 | 1632篇 |
1995年 | 1945篇 |
1994年 | 1812篇 |
1993年 | 1780篇 |
1992年 | 3622篇 |
1991年 | 3837篇 |
1990年 | 3766篇 |
1989年 | 3742篇 |
1988年 | 3388篇 |
1987年 | 3422篇 |
1986年 | 3553篇 |
1985年 | 3431篇 |
1984年 | 2758篇 |
1983年 | 2480篇 |
1982年 | 1696篇 |
1981年 | 1574篇 |
1979年 | 2533篇 |
1978年 | 2006篇 |
1977年 | 1629篇 |
1976年 | 1648篇 |
1975年 | 1782篇 |
1974年 | 2189篇 |
1973年 | 2210篇 |
1972年 | 2127篇 |
1971年 | 2076篇 |
1970年 | 1979篇 |
1969年 | 1840篇 |
1967年 | 1642篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
A Yabuki S Suzuki M Matsumot M Kurohmaru Y Hayashi H Nishinakagawa 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2001,63(12):1339-1342
The proximal straight tubules of the female mouse kidney exhibit heavy periodic acid Schiff (PAS) staining in their brush borders and numerous cytoplasmic granules. In the present study, the female DBA/2Cr mouse kidney was examined, using various fixatives (formalin, PFA, PLP, Zamboni's, Bouin, or Carnoy solution) and various staining methods (HE, PAS, alcian blue, periodic acid methenamine-silver (PAM), toluidine blue, azan, or Congo red). Under azan and PAM, the staining pattern of the brush border was similar to that of PAS, and few effects of the fixative were observed. Cytoplasmic granules were clearly detected with PAM as well as PAS. However, these granules were not detected with Carnoy solution. Furthermore, distribution of granules differed between PAS and PAM. 相似文献
2.
R K?stlin 《Tier?rztliche Praxis》1988,16(4):351, 436-351, 437
3.
The crossreactivity of mouse monoclonal antibodies (MoAbs) (Tab. I) prepared against human HLA-DR and HLA-DP antigens was studied in various bovine cells: lymphocytes from lymph nodes and peripheral blood, adherent (B) and nonadherent (T) lymphocytes, monocytes, granulocytes and platelets. In the immunofluorescence test, MoAbs Bra13, Bra14, Bra20, Bra22, Bra30, Bra70, HL-38 reacted with bovine B lymphocytes and monocytes, but not with other tested cells (Tab. III, IV). These antibodies, except Bra22, were positive with B lymphocytes in the complement dependent cytotoxic test (Tab. II). The similarity of the bovine antigens and HLA-DR antigens determined by used MoAbs was also proved by immunoblotting. Monoclonal antibodies Bra38 and BraFB6 did not react with the bovine cells and separated antigens. The epitope (HLA-DR) recognized by the antibody Bra38 is probably absent in cattle. The presence of HLA-DP analogue determined by the antibody BraFB6 has not been confirmed. The crossreactive MoAbs could be used for the detection of B lymphocytes and macrophages in veterinary immunology. 相似文献
4.
5.
Intravenous frusemide (1.0 mg/kg bwt) or phentolamine (0.33 mg/kg bwt) was given to 7 horses 1 h before exercise and their effects on pulmonary artery and aortic pressure changes during strenuous exercise were examined. Short-term near-maximal treadmill exercise (10 m/sec, 3 degrees incline) produced increases in heart rate, mean pulmonary artery pressure (PAP), mean aortic pressure (AP), and packed cell volume (PCV). Frusemide did not affect heart rate, PAP or PCV during exercise. Frusemide significantly decreased mean AP by 10 to 15 mmHg during exercise. Phentolamine produced an increase in heart rate relative to control only early in exercise but not during later, more strenuous, exercise. Phentolamine had no statistically significant effect on AP, PAP, or PCV, but a significant reduction was observed between 180 and 230 sec of exercise when PAP and AP were standardised against heart rate. Frusemide did not prevent horses from haemorrhaging during exercise in this study. Treatment with phentolamine did not sufficiently reduce the PAP and AP to test our hypothesis that a reduction in PAP and AP would eliminate EIPH. 相似文献
6.
S A Dee 《Veterinary Clinics of North America: Food Animal Practice》1992,8(3):641-660
Porcine urogenital disease is the result of an imbalance of the normal microflora of the urinary and reproductive tracts brought about by hormonal, environmental, and management-related stress factors. Production and economic losses can be substantial, and diagnosing and treating the problem can be frustrating. Through proper hygiene, facility design, and culling procedures, the severity of the problem can be minimized. 相似文献
7.
M Onuma Y Yasutomi M Yamamoto S Watarai T Yasuda Y Kawakami 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1989,36(2):139-147
Monoclonal antibody c143 against tumor-associated antigen (TAA) expressed on bovine leukemia cells was conjugated to liposomes containing adriamycin (ADM), and therapeutic effects of conjugates were examined in leukemic or preleukemic cows to prevent the progression of the disease. Five cows with TAA-positive in their peripheral blood lymphocytes were divided into two groups. Each group of cows received 4 injections of ADM alone (0.4 mg/kg) or c143-conjugated liposomes containing the same dose of ADM (L-AMD-c143) through the jugular vein at about 4 day intervals. In three animals treated with L-ADM-c143, the TAA-positive cells gradually decreased with treatment and finally two animals became TAA-negative during a 6 week period and a 14 week period after treatment, respectively. In the control, two animals treated with ADM alone showed only a slight decrease of TAA-positive cells. 相似文献
8.
Kevin R. Stuart Arnold G. Eversole David E. Brune 《Journal of the World Aquaculture Society》2001,32(1):105-111
Abstract.— The freshwater mussel Elliptio complanata was provided water containing green algae and cyanobacteria delivered from the Partitioned Aquaculture System (PAS) at eight flow rates to determine algal filtration rates as mg of particulate organic carbon (POC)/kg wet tissue weight per h. The dominant taxon in cyanobacterial waters was Microcystis while the dominant taxa in green algal waters were Scenedesmus and Ankistrodesmus . The cell counts of Scenedesmus and Ankistrodesmus were the only algal taxa that were significantly different between the incoming water and water filtered by mussels. Filtration rates of POC obtained from green algal water were significantly greater than from cyanobacteria-dominated waters at all flow rates. A significant increase in mean filtration rate was observed as flow rates increased. The filtration rate of green algae increased as POC concentration increased, peaking at 28 mg C/L. A maximum filtration rate was not observed with cyanobacterial waters. 相似文献
9.
Y Nagashima H Hirao S Furukawa K Hoshi M Akahane R Tanaka Y Yamane 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2001,63(11):1199-1202
Fifteen and eight mature beagles, without (normal group) and with experimental mitral regurgitation (MR group), respectively, were given 0.02 mg/kg/day digoxin powder for 10 days orally. The optimum time for sample collection after administration of digoxin was observed to be 8-18 hr and 10-22 hr in the normal and MR groups, respectively. In both groups, a stable concentration was reached after 3-5 days of treatment. No differences in plasma level were observed between sexes. The optimum concentration of digoxin was attained at an earlier stage than has been previously reported for both dogs and humans. 相似文献
10.
E Oohashi K Yagi Y Uzuka S Tanabe T Sarashina T Ishida 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2001,63(11):1241-1243
The purpose of this study was to evaluate seasonal influences on thyroid hormone levels of healthy outdoor dogs in Hokkaido. We surveyed serum basal total thyroxine (tT4), free thyroxine (fT4), and canine thyroid-stimulating hormone (cTSH) levels, and tT4 levels after administration of TSH for a year. Basal tT4 levels decreased in January, and increased in August and September. fT4 levels increased in January and November. No significant seasonal variation was found in cTSH. tT4 levels after administration of TSH in August and November increased. These results suggested that the thyroid gland may have been activated in November. We should take seasonal variation into consideration when thyroid function is tested. 相似文献