全文获取类型
收费全文 | 755篇 |
免费 | 28篇 |
国内免费 | 2篇 |
专业分类
林业 | 49篇 |
农学 | 56篇 |
209篇 | |
综合类 | 52篇 |
农作物 | 100篇 |
水产渔业 | 25篇 |
畜牧兽医 | 234篇 |
园艺 | 11篇 |
植物保护 | 49篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 14篇 |
2019年 | 18篇 |
2018年 | 21篇 |
2017年 | 16篇 |
2016年 | 16篇 |
2015年 | 23篇 |
2014年 | 30篇 |
2013年 | 38篇 |
2012年 | 54篇 |
2011年 | 50篇 |
2010年 | 30篇 |
2009年 | 28篇 |
2008年 | 52篇 |
2007年 | 49篇 |
2006年 | 39篇 |
2005年 | 35篇 |
2004年 | 24篇 |
2003年 | 32篇 |
2002年 | 33篇 |
2001年 | 26篇 |
2000年 | 17篇 |
1999年 | 17篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1983年 | 2篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 4篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1965年 | 2篇 |
1964年 | 2篇 |
1963年 | 3篇 |
排序方式: 共有785条查询结果,搜索用时 15 毫秒
101.
Journal of Soils and Sediments - Soil loss by rainfall is a serious problem in civil and environmental engineering. In this study, microbially induced calcite precipitation (MICP) was applied to... 相似文献
102.
Organic farming (OF) is a fast growing alternative for sustainable agriculture in Korea. However, information on the effects of OF on the soil properties and environmental conservation is limited. In order to determine the effects of OF on the soil properties, 31 fields under OF (hereafter referred to as "OF fields") and 61 fields under conventional farming (CF) (hereafter referred to as "CF fields") in plastic film houses were selected throughout Korea and the soil chemical properties were investigated, including the P distribution characteristics. Average organic matter (OM) content was significantly higher (44 g kg-1) in the OF fields then in the CF fields (24 g kg-1). Bray-2 P values were 986 and 935 mg kg-1 in the OF and CF soils, respectively, markedly exceeding the optimum range. Average total P (T-P) values were 2,973 mg kg-1 in the OF fields and 1,830 mg kg-1 in the CF fields. The high T-P values were due to repeated application of manure compost with a low N/P ratio. Inorganic P was the dominant fraction with 62–65% of T-P. The amounts of residual and organic P were significantly lower. The level of OF organic P was significantly higher (453 mg kg-1) compared to the 106 mg kg-1 value for the CF fields. Fractionation of soil inorganic P showed that Ca-P predominated with 1,332 mg kg-1 in the OF fields, which was associated with soil pH values over 6.0. The main inorganic P fraction in the CF soils whose pH values were generally less than 6.0 consisted of Al-/Fe-P. The levels of water-soluble P was significantly higher (65 mg kg-1) in the OF fields than in the CF fields (24 mg kg-1). These results indicated that the OF system may lead to a serious degradation of the soil environment due to the accumulation of phosphorus and may be an important source of water pollution compared to the CF systems in Korea. 相似文献
103.
D. U. Han C. Choi J. Kim W.‐S. Cho H.‐K. Chung S.‐K. Ha K. Jung C. Chae 《Zoonoses and public health》2002,49(7):346-348
The in vitro susceptibilities of 128 isolates of east1+Escherichia coli from pre‐weaned and post‐weaned pigs with diarrhoea were tested with nine commonly used anti‐microbial agents by an agar dilution minimal inhibitory concentration (MIC) procedure according to National Committee for Clinical Laboratory Standards guidelines. For the isolates from pre‐weaned and post‐weaned pigs, most of them were susceptible to low concentrations (MIC90) of tetracycline (4 and 2 μg/ml), ceftiofur (2 and 2 μg/ml), and colistin (4 and 2 μg/ml). Marked resistance was found in others. 相似文献
104.
D.J. Chung A. Wong K. Hayashi C.E. Yellowley 《Veterinary journal (London, England : 1997)》2014,199(1):123-130
Adipose tissue-derived mesenchymal stromal cells (AT-MSCs) are good candidates for cell therapy due to the accessibility of fat tissue and the abundance of AT-MSCs therein. Neurospheres are free-floating spherical condensations of cells with neural stem/progenitor cell (NSPC) characteristics that can be derived from AT-MSCs. The aims of this study were to examine the influence of oxygen (O2) tension on generation of neurospheres from canine AT-MSCs (AT-cMSCs) and to develop a hypoxic cell culture system to enhance the survival and therapeutic benefit of generated neurospheres.AT-cMSCs were cultured under varying oxygen tensions (1%, 5% and 21%) in a neurosphere culture system. Neurosphere number and area were evaluated and NSPC markers were quantified using real-time quantitative PCR (qPCR). Effects of oxygen on neurosphere expression of hypoxia inducible factor 1, α subunit (HIF1A) and its target genes, erythropoietin receptor (EPOR), chemokine (C-X-C motif) receptor 4 (CXCR4) and vascular endothelial growth factor (VEGF), were quantified by qPCR. Neural differentiation potential was evaluated in 21% O2 by cell morphology and qPCR.Neurospheres were successfully generated from AT-cMSCs at all O2 tensions. Expression of nestin mRNA (NES) was significantly increased after neurosphere culture and was significantly higher in 1% O2 compared to 5% and 21% O2. Neurospheres cultured in 1% O2 had significantly increased levels of VEGF and EPOR. There was a significant increase in CXCR4 expression in neurospheres generated at all O2 tensions. Neurosphere culture under hypoxia had no negative effect on subsequent neural differentiation. This study suggests that generation of neurospheres under hypoxia could be beneficial when considering these cells for neurological cell therapies. 相似文献
105.
Olivier M Aggarwal A Allen J Almendras AA Bajorek ES Beasley EM Brady SD Bushard JM Bustos VI Chu A Chung TR De Witte A Denys ME Dominguez R Fang NY Foster BD Freudenberg RW Hadley D Hamilton LR Jeffrey TJ Kelly L Lazzeroni L Levy MR Lewis SC Liu X Lopez FJ Louie B Marquis JP Martinez RA Matsuura MK Misherghi NS Norton JA Olshen A Perkins SM Perou AJ Piercy C Piercy M Qin F Reif T Sheppard K Shokoohi V Smick GA Sun WL Stewart EA Fernando J Tejeda Tran NM Trejo T Vo NT Yan SC Zierten DL Zhao S 《Science (New York, N.Y.)》2001,291(5507):1298-1302
We have constructed a physical map of the human genome by using a panel of 90 whole-genome radiation hybrids (the TNG panel) in conjunction with 40,322 sequence-tagged sites (STSs) derived from random genomic sequences as well as expressed sequences. Of 36,678 STSs on the TNG radiation hybrid map, only 3604 (9.8%) were absent from the unassembled draft sequence of the human genome. Of 20,030 STSs ordered on the TNG map as well as the assembled human genome draft sequence and the Celera assembled human genome sequence, 36% of the STSs had a discrepant order between the working draft sequence and the Celera sequence. The TNG map order was identical to one of the two sequence orders in 60% of these discrepant cases. 相似文献
106.
Mao JH Kim IJ Wu D Climent J Kang HC DelRosario R Balmain A 《Science (New York, N.Y.)》2008,321(5895):1499-1502
The enzyme mTOR (mammalian target of rapamycin) is a major target for therapeutic intervention to treat many human diseases, including cancer, but very little is known about the processes that control levels of mTOR protein. Here, we show that mTOR is targeted for ubiquitination and consequent degradation by binding to the tumor suppressor protein FBXW7. Human breast cancer cell lines and primary tumors showed a reciprocal relation between loss of FBXW7 and deletion or mutation of PTEN (phosphatase and tensin homolog), which also activates mTOR. Tumor cell lines harboring deletions or mutations in FBXW7 are particularly sensitive to rapamycin treatment, which suggests that loss of FBXW7 may be a biomarker for human cancers susceptible to treatment with inhibitors of the mTOR pathway. 相似文献
107.
An adult female Eastern Grey kangaroo (Macropus giganteus) was examined for lameness due to a mass located at the right tibiotarsal joint. Radiographs revealed a metal arrowhead‐shaped foreign body within the mass alongside a pathologic fracture. Grossly, at necropsy, there was a multilobulated and haemorrhagic mass with intralesional metal fragments, associated osteolysis of the tibiotarsus and pulmonary metastatic nodules. Histologically the neoplasm was composed of plump elongated and fusiform cells that often formed concentrically around small vessels. The pulmonary nodules were composed of similar neoplastic cells, necrosis and haemorrhage. Neoplastic cells were positive immunohistochemically for vimentin and smooth muscle actin. The histological features, immunohistochemical profiles and behaviour of this tumour support a diagnosis of a primary angioleiomyosarcoma with lung metastasis associated with a metal foreign body. 相似文献
108.
Hyun-Jung Suh Dai Jung Chung A-Jin Lee Hyo-Jin Chung Dae-Hyun Kim Ki-Dong Eom Sun Hee Do Hwi-Yool Kim 《The Canadian veterinary journal. La revue veterinaire canadienne》2015,56(10):1025-1028
A 10-year-old Maltese dog was presented with a firm mass on the left side of his neck. Physical examination confirmed a firm mass in the left and a submandibular swelling in the right cervical region. Sialolithiasis and associated sialocele in both mandibular salivary glands were suspected and bilateral sialoadenectomy was performed. The stones were identified as non-mineral sialoliths. 相似文献
109.
110.
Coupling of stress in the ER to activation of JNK protein kinases by transmembrane protein kinase IRE1 总被引:2,自引:0,他引:2
Urano F Wang X Bertolotti A Zhang Y Chung P Harding HP Ron D 《Science (New York, N.Y.)》2000,287(5453):664-666
Malfolded proteins in the endoplasmic reticulum (ER) induce cellular stress and activate c-Jun amino-terminal kinases (JNKs or SAPKs). Mammalian homologs of yeast IRE1, which activate chaperone genes in response to ER stress, also activated JNK, and IRE1alpha-/- fibroblasts were impaired in JNK activation by ER stress. The cytoplasmic part of IRE1 bound TRAF2, an adaptor protein that couples plasma membrane receptors to JNK activation. Dominant-negative TRAF2 inhibited activation of JNK by IRE1. Activation of JNK by endogenous signals initiated in the ER proceeds by a pathway similar to that initiated by cell surface receptors in response to extracellular signals. 相似文献