全文获取类型
收费全文 | 239篇 |
免费 | 8篇 |
专业分类
林业 | 16篇 |
农学 | 62篇 |
37篇 | |
综合类 | 17篇 |
农作物 | 14篇 |
水产渔业 | 5篇 |
畜牧兽医 | 68篇 |
园艺 | 6篇 |
植物保护 | 22篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2019年 | 8篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 6篇 |
2014年 | 9篇 |
2013年 | 12篇 |
2012年 | 10篇 |
2011年 | 10篇 |
2010年 | 12篇 |
2009年 | 5篇 |
2008年 | 9篇 |
2007年 | 5篇 |
2006年 | 9篇 |
2005年 | 3篇 |
2003年 | 3篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1987年 | 5篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 8篇 |
1973年 | 1篇 |
1971年 | 4篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1967年 | 4篇 |
1966年 | 4篇 |
排序方式: 共有247条查询结果,搜索用时 15 毫秒
71.
Microbial activity at gigapascal pressures 总被引:1,自引:0,他引:1
Sharma A Scott JH Cody GD Fogel ML Hazen RM Hemley RJ Huntress WT 《Science (New York, N.Y.)》2002,295(5559):1514-1516
We observed physiological and metabolic activity of Shewanella oneidensis strain MR1 and Escherichia coli strain MG1655 at pressures of 68 to 1680 megapascals (MPa) in diamond anvil cells. We measured biological formate oxidation at high pressures (68 to 1060 MPa). At pressures of 1200 to 1600 MPa, living bacteria resided in fluid inclusions in ice-VI crystals and continued to be viable upon subsequent release to ambient pressures (0.1 MPa). Evidence of microbial viability and activity at these extreme pressures expands by an order of magnitude the range of conditions representing the habitable zone in the solar system. 相似文献
72.
M. Di Vito K. B. Singh N. Greco M. C. Saxena 《Genetic Resources and Crop Evolution》1996,43(2):103-107
Summary Among the nematodes infesting chickpea (Cicer arietinum L.) plants in Syria, cyst nematode (Heterodera ciceri Vovlas, Greco et Di Vito) is the most important. It is uneconomical to grow chickpea in fields infested with cyst nematode and to control this nematode with nematicide. Therefore, investigations were conducted at ICARDA, Syria from 1987 to 1991 to identify sources of resistance to cyst nematode in 7258 lines of C. arietinum and 102 lines of eight annual Cicer species including C. bijugum K.R. Rech. (13 lines), C. chorassanicum (Bge) M. Pop. (3 lines), C. cuneatum Hochst. ex Rich. (3 lines), C. echinospermum P.H. Davis (8 lines), C. judaicum Boiss. (18 lines), C. pinnatifidum Jaub. & Sp. (18 lines), C. reticulatum Ladiz. (36 lines), and C. yamashitae Kitamura (3 lines). All lines were grown in a greenhouse at 15–25°C in pots containing soil infested with 20 eggs of the nematode g-1 soil. Nematode infestation was evaluated on a 0 to 5 scale based on number of females and cysts on roots. Resistance was found in one line of C. bijugum, six lines of C. pinnatifidum, and one line of C. reticulatum. No lines of C. arietinum, C. chorassanicum, C. cuneatum, C. echinospermum, C. judaicum, or C. yamashitae was resistant to cyst nematode. Plants with resistance have been recovered in the F3 generation from crosses between the cultigen and C. reticulatum, indicating the possibility of transfer of gene(s) for resistance to cyst nematode from wild to cultivated Cicer species.Joint contribution from Istituto di Nematologia Agraria, ICARDA and ICRISAT (International Crops Research Institute for the Semi-Arid Tropics), Patancheru P.O., A.P. 502 324, India. 相似文献
73.
Summary Natural out-crossing imposes considerable costs and inefficiencies in breeding, evaluation and commercialization of pigeonpea (Cajanus cajan (L.) Millsp.). This note reports identification of a modification of floral morphology which inhibits cross-fertilization. Floral morphology and possible mechanisms of action of this character are discussed.On leave from International Crops Research Institute for the Semi-Arid Tropics (ICRISAT). Hyderabad, India. 相似文献
74.
Summary Microsporogenesis and anther wall development of male-sterile and fertile lines in pigeon pea (Cajanus cajan (L.) Millsp.) was examined microscopically. Male-sterility was complete and was caused by breakdown at the young tetrad stage. Degeneration of the tapetum by vacuolation occurred during the first division of meiosis and appeared responsible for pollen mother cell breakdown. Sterile plants also differed from the fertile plants in the enlargement of the inner middle layer of the anther wall, and in the lack of development of the endothecium. 相似文献
75.
76.
3,4-Dichloroaniline (DCA), a biodegradation intermediate of numerous herbicides, binds covalently to soil humus to form persistent complexes. Prompted by the possibility that, upon repeated treatments, xenobiotic residues may accumulate in humus, the turnover rates of intact, solvent-extracted, and hydrolyzed humic complexes of 14C-DCA were compared with that of similarly-treated soil organic matter fractions. The turnover rate of intact humic-DCA complexes was considerably faster than the average turnover of soil organic matter. Humic-DCA complexes, that had been washed in solvents to remove adsorbed DCA or hydrolyzed to break susceptible chemical bonds, had turnover rates that were equal to or slower than that of the average soil organic matter, respectively. However, the turnover rates of the solvent-washed and hydrolyzed humic-DCA complexes were similar to that of identically-treated humic acid. The evidence indicates that an extensive accumulation of DCA or similar herbicide-derived halogenated anilines in soil organic matter is unlikely. 相似文献
77.
Mishra SK Khan AA Narayan R Singh SP Pratap SO Saxena D Chaudhuri D 《British poultry science》2011,52(6):686-693
1. The inheritance of various plumage colour variants and their underlying interactions were investigated in a large flock of Japanese quail maintained at CARI (India) by conducting reciprocal crosses between four breeding stocks inheriting Pharaoh, White Breasted, White and Brown plumages, followed by test crosses. 2. Based on the proportion of plumage-colour types in the progeny, putative genotypes were determined for parents and offspring for each of the crosses. 3. The White and Brown phenotypes were attributed to the Panda (S) and Roux (Br) loci respectively in agreement with contemporary quail stocks. 4. The White Breasted plumage type present in our stock was caused by a novel mutation with dominant gene action at an autosomal locus that was not allelic to either Panda or the White feather locus. 5. A recessive epistatic action of the Panda locus (S) on White Breasted (Wb) resulted in a White colour phenotype. 6. A novel phenotype, White Breasted-Brown was co-expressed with the Br and Wb loci. 7. It was concluded that breeding for customized feather colour phenotypes in Japanese quail using colour mutations was feasible and would be advantageous in order to overcome the limitations of legislation to protect wildlife in India. 相似文献
78.
Bhawna Saxena Rajinder Kaur Satya Vrat Bhardwaj 《Journal of Crop Science and Biotechnology》2011,14(3):191-196
Genetic relationship and diversity among seven cabbage cultivars were analyzed using RAPD and SSR markers. These cultivars
are of great commercial value in India and are confirmed for their reaction to black rot caused by Xanthomonas campestris pv. campestris. However, so far the extent of genetic diversity and relatedness has not been studied in these cultivars. A total of 17 selected
RAPD primers generated 90 bands, 76 of which were polymorphic (84.44%). In addition, 27 selected SSR primers generated 67
amplified bands with 59 of which were polymorphic (87.6%). Though both the marker techniques were able to discriminate the
cultivars effectively, analysis of combined data of markers (RAPD and SSR) resulted in better distinction of cultivars. By
combining both the markers, a total of 157 bands were detected of which 135 bands (85.98%) were polymorphic, i.e. an average
of 5.95 bands per primer. High level of polymorphism (> 85%) recorded with two different marker systems indicated a high level
of genetic variation existing among the cultivars. Genetic relationship estimated using similarity co-efficient (Jaccard’s)
values between different pairs of cultivars varied from 0.21 to 0.77 in RAPD, 0.42 to 0.82 in SSR, and 0.43 to 0.89 with combined
markers. A high correspondence had been recorded between the values of genetic variations generated by UPGMA, clustering,
and scatter plot diagrams. The cultivars ‘January King Sel. Improved’ and ‘Golden Acre’ are highly divergent cultivars as
demonstrated by both the marker systems. 相似文献
79.
Ranjithkumar M Kamili NM Saxena A Dan A Dey S Raut SS 《Veterinary parasitology》2011,180(3-4):349-353
Oxidant/antioxidant equilibrium disturbance has already been reported in trypanosome infections by several authors. The present study was aimed to explore the possible oxidant/antioxidant disturbance in surra of naturally infected horses before and after treatment. Fifteen naturally infected horses were chosen to analyse erythrocytic indices, platelet counts, lipid peroxides (LPO), nitric oxide (NO), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) while six healthy animals acted as control. There was a highly significant (P<0.001) reduction in red blood cell (RBC) count, haemoglobin (Hb), packed cell volume (PCV) and platelet levels and a significant reduction in mean corpuscular haemoglobin concentration (MCHC) (P<0.05) was noticed. A highly significant increase in NO (P<0.001), a significant increase in LPO (P<0.05) and a significant decrease in GSH, SOD and CAT (P<0.05) were found. A negative correlation of RBC count with LPO (r=-0.844) and nitrate (r=-0.702) while a positive correlation with GSH (r=0.489), SOD (r=0.580) and CAT (r=0.689) was observed. All the animals were treated with Quinapyramine sulphate (3mg/kg s.c.) only once. Nine animals recovered completely without any side effects. The recovered animals were monitored and samples were collected every seven days for up to 21 days and parameters were analysed. After treatment, a significant increase in haematological parameters was noticed whereas the oxidative indices varied without any statistical significance. To conclude, the increase in oxidant parameters and decrease in antioxidant enzymes in infected horses indicates the disturbance of oxidant/antioxidant indices. There was a significant increase in post therapy haematological values, while the oxidant/antioxidant indices changed insignificantly indicating that antioxidants might be supplemented in the therapeutic regimen. 相似文献
80.
BB Saxena A Clavio M Singh P Rathnam Y Bukharovich T Reimers Jr A Saxena & Scott Perkins 《Reproduction in domestic animals》2002,37(1):9-17
Adult female dogs were immunized with 0.5 mg bovine luteinizing hormone receptor (LH-R) encapsulated in a silastic subdermal implant and subsequently with four intramuscular booster injections of 0.1 mg LH-R each. Circulating LH-R antibody was detected in the sera 3 weeks post-implant. The appearance of LH-R antibody was associated with a decline in the serum progesterone concentrations to a range of 0–0.5 ng/ml until day 365 in the immunized dogs in comparison with a range of 5–10 ng in the control animals, suggesting a lack of ovulation and corpus luteum function in immunized dogs. The immunized dogs did not show signs of `standing heat' and failed to ovulate when induced by LH-RH challenge. Serum oestradiol levels, however, remained in the range of 30–40 pg/ml in both the immunized and the control dogs. With the decline in the antibody titres, the hormonal profile and vaginal cytology returned to a fertile state and the dogs exhibited signs of `standing heat', as well as vaginal bleeding. Dogs immunized with LH-R did not show any serious metabolic, local or systemic adverse effects. The hypothalamic–pituitary gonadal axis remained intact as indicated by little difference in pituitary LH levels between control and immunized animals, and by the release of LH by LH-RH challenge. These studies demonstrate that active immunization of female dogs with LH-R could immunomodulate ovarian function to cause a reversible state of infertility. It may be postulated that, due to extensive interspecies homology, a recombinant LH receptor-based immunocontraceptive vaccine may also be effective in other vertebrates. 相似文献