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排序方式: 共有207条查询结果,搜索用时 218 毫秒
191.
192.
Jaume Arnó Alexandre Escolà Josep M. Vallès Jordi Llorens Ricardo Sanz Joan Masip Jordi Palacín Joan R. Rosell-Polo 《Precision Agriculture》2013,14(3):290-306
Estimation of grapevine vigour using mobile proximal sensors can provide an indirect method for determining grape yield and quality. Of the various indexes related to the characteristics of grapevine foliage, the leaf area index (LAI) is probably the most widely used in viticulture. To assess the feasibility of using light detection and ranging (LiDAR) sensors for predicting the LAI, several field trials were performed using a tractor-mounted LiDAR system. This system measured the crop in a transverse direction along the rows of vines and geometric and structural parameters were computed. The parameters evaluated were the height of the vines (H), the cross-sectional area (A), the canopy volume (V) and the tree area index (TAI). This last parameter was formulated as the ratio of the crop estimated area per unit ground area, using a local Poisson distribution to approximate the laser beam transmission probability within vines. In order to compare the calculated indexes with the actual values of LAI, the scanned vines were defoliated to obtain LAI values for different row sections. Linear regression analysis showed a good correlation (R 2 = 0.81) between canopy volume and the measured values of LAI for 1 m long sections. Nevertheless, the best estimation of the LAI was given by the TAI (R 2 = 0.92) for the same length, confirming LiDAR sensors as an interesting option for foliage characterization of grapevines. However, current limitations exist related to the complexity of data process and to the need to accumulate a sufficient number of scans to adequately estimate the LAI. 相似文献
193.
194.
Sabrina Gacem Marion Papas Jaime Catalan Jordi Miró 《Reproduction in domestic animals》2020,55(2):181-188
The accessory sex glands play a major role in the production of seminal plasma, and testicular artery blood flow seems to strongly influence testicular function. However, very little ultrasound imaging of these organs has been undertaken in donkeys. The present work reports the results of such examinations in five jackasses along the year. The accessory glands were inspected by B-mode ultrasound while the testicular artery blood flow was assessed by colour pulsed-wave Doppler ultrasound. The testicular artery was examined at pampiniform plexus (PPT), supratesticular area (ST) and capsular artery (CA). Values were recorded for the total arterial blood flow (TABF), peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI), pulsatility index (PI) and time average maximum velocity (TAMV). Semen was obtained and assessed for sperm concentration, viability, abnormalities and motility using a CASA system. The bulbourethral glands, prostate and ductus deferens ampullae were relatively larger than in the stallion. Bulbourethral glands and ampullae sizes were inversely correlated with sperm motility. An reduction in blood flow between the level the PPP and the CA was observed, helping to reduce testis temperature and oxygen pressure. Blood flow at the CA showed the strongest correlation with semen production. PI and RI were positively correlated with the CASA motility variable STR (p = .02, p = .06) and sperm viability (p = .01), while sperm concentration (p = .05) correlated inversely with PSV, EDV, TAMV and TABF. EDV also correlated negatively with the CASA variables VSL, LIN, STR and VAP (p ≤ .05). PI and RI were also negatively correlated with testis length (p = .0093, p = −.0438). 相似文献
195.
196.
Fluctuations of landings and environmental conditions in the north-western Mediterranean Sea 总被引:12,自引:1,他引:12
Josep Lloret Jordi Lleonart Ignasi Solé & Jean-Marc Fromentin 《Fisheries Oceanography》2001,10(1):33-50
Most of the monthly catches and CPUE of 13 studied commercial species in the coastal waters of the north-western Mediterranean were significantly positively correlated with run-off of local rivers (Rhône and Muga) and the wind mixing index during the spawning season, with time lags of less than a year (transfer function analyses). Rhône and Ebre interannual fluctuations in run-off were synchronous and were related to the North Atlantic Oscillation (NAO), river run-offs being negatively correlated to high NAO episodes. The fluctuations of river discharges and the wind mixing index were cyclic but not related. The results showed that enhanced hydroclimatic conditions in the NW Mediterranean were favourable for the productivity of the fish and invertebrate stocks, and suggest the presence of linkage between recruitment of Mediterranean species and local (river discharges, wind conditions) and global (NAO) environmental conditions. 相似文献
197.
Eva BLANCH Cristina TOMáS Marta HERNáNDEZ Jordi ROCA Emilio A. MARTíNEZ Juan M. VáZQUEZ Eva MOCé 《The Journal of reproduction and development》2014,60(2):143-149
Egg yolk (EY) and glycerol are common constituents of extenders used for sperm
cryopreservation. It has been demonstrated that using cholesterol-loaded cyclodextrins
(CLC) improves sperm cryosurvival in several species. However, standard freezing extenders
might not be the most appropriate for CLC-treated sperm. This study evaluated the EY and
glycerol requirements for freezing CLC-treated boar spermatozoa. Semen samples from 34
ejaculates coming from 4 boars were used. Each ejaculate was split into three aliquots:
one was used untreated (control), and the other two were treated with 1 mg of CLC or
methyl-β-cyclodextrin/120 × 106 sperm for 15 min at 22 C prior to
cryopreservation. Our results indicated that reducing the concentration of EY was
detrimental for sperm viability after thawing (31.57 ± 2 vs. 19.89% ± 2
for 20 and 10% EY, respectively; P <0.05), even in semen treated with CLC. On the other
hand, it was observed that the traditional concentration of glycerol (3%) was not the
appropriate for freezing CLC-treated sperm (61.10 ± 3 vs. 47.87% ± 3 viable sperm for
control and CLC-treated sperm, respectively; P <0.05). Thus, CLC-treated sperm showed a
higher tolerance to high glycerol concentrations (5%) in terms of sperm viability (59.19%
± 3) than non-treated sperm (45.58% ± 3; P<0.05). Therefore, it could be necessary to
modify the freezing extenders for CLC-treated sperm. Nevertheless, additional studies will
be needed to evaluate alternative cryoprotectants and to determine the effect of high
glycerol concentrations on sperm functionality. 相似文献
198.
Miguel Angel ANGEL Maria Antonia GIL Cristina CUELLO Jonatan SANCHEZ-OSORIO Jesus GOMIS Inmaculada PARRILLA Jordi VILA Ignacio COLINA Marta DIAZ Josep REIXACH Jose Luis VAZQUEZ Juan Maria VAZQUEZ Jordi ROCA Emilio A. MARTINEZ 《The Journal of reproduction and development》2014,60(5):371-376
This study aimed to evaluate the effect of recipient-donor estrous cycle synchrony on recipient reproductive performance
after nonsurgical deep-uterine (NsDU) embryo transfer (ET). The transfers (N=132) were conducted in recipients sows that
started estrus 24 h before (–24 h; N=9) or 0 h (synchronous; N=31), 24 h (+24 h; N=74) or 48 h (+48 h; N=18) after the
donors. A total of 30 day 5 morulae or day 6 blastocysts (day 0=onset of estrus) were transferred per recipient. The highest
farrowing rates (FRs) were achieved when estrus appeared in recipients 24 h later than that in the donors (81.1%), regardless
of the embryonic stage used for the transfers. The FR notably decreased (P<0.05) when recipients were –24 h asynchronous
(0%), synchronous (61.3%) or +48 h asynchronous (50%) relative to the donors. No differences in litter size (LS) and piglet
birth weights were observed among the synchronous and +24 h or +48 h asynchronous groups. While a +24 h asynchronous
recipient was suitable for transfers performed with either morulae (FR, 74.3%; LS, 9.2 ± 0.6 piglets) or blastocysts (FR,
84.6%; LS, 9.8 ± 0.6 piglets), a + 48 h asynchronous recipient was adequate for blastocysts (FR, 87.5%; LS, 10.4 ± 0.7
piglets) but not for morulae (FR, 30.0%; LS, 7.3 ± 2.3 piglets). In conclusion, this study confirms the effectiveness of the
NsDU-ET technology and shows that porcine embryos tolerate better a less advanced uterine environment if they are
nonsurgically transferred deep into the uterine horn. 相似文献
199.
Tulipani S Urpi-Sarda M Garcı́a-Villalba R Rabassa M López-Uriarte P Bulló M Jáuregui O Tomás-Barberán F Salas-Salvadó J Espı́n JC Andrés-Lacueva C 《Journal of agricultural and food chemistry》2012,60(36):8930-8940
Walnuts ( Juglans regia L.), hazelnuts ( Corylus avellana L.), and almonds ( Prunus dulcis Mill.) are rich sources of ellagitannins and proanthocyanidins. Gut microbiota plays a crucial role in modulating the bioavailability of these high molecular weight polyphenols. However, to date there are no studies evaluating the capacity to produce nut phenolic metabolites in subjects with metabolic syndrome (MetS), a pathology associated with an altered gut bacterial diversity. This study applied a LC-MS targeted approach to analyze the urinary excretion of nut phenolic metabolites in MetS subjects following 12 weeks of nut consumption, compared to sex- and age-matched individuals given a nut-free control diet. Metabolites were targeted in both hydrolyzed and nonhydrolyzed urine by LC-PDA-QqQ-MS/MS analysis, and identification of metabolites lacking available standards was confirmed by LC-ESI-ITD-FT-MS. Ellagitannin-derived urolithins A and B significantly increased after the nut-enriched-diet, urolithins C and D were also detected, and a complex combination of urolithin-conjugated forms was observed in nonhydrolyzed urine, confirming an extensive phase II metabolism after absorption. In contrast, no significant increases in proanthocyanidin microbial metabolites were observed in urine following nut consumption. Because the intestinal microbiota of the subjects in this study could catabolize ellagitannins into a wide range of urolithins, further research is strongly warranted on the in vivo potential of these microbial metabolites in reducing cardiometabolic risk. 相似文献
200.
Miralda-Escudé J 《Science (New York, N.Y.)》2003,300(5627):1904-1909
The Dark Age is the period between the time when the cosmic microwave background was emitted and the time when the evolution of structure in the universe led to the gravitational collapse of objects, in which the first stars were formed. The period of reionization started with the ionizing light from the first stars, and it ended when all the atoms in the intergalactic medium had been reionized. The most distant sources of light known at present are galaxies and quasars at redshift z congruent with 6, and their spectra indicate that the end of reionization was occurring just at that time. The Cold Dark Matter theory for structure formation predicts that the first sources formed much earlier. 相似文献