全文获取类型
收费全文 | 652篇 |
免费 | 30篇 |
国内免费 | 1篇 |
专业分类
林业 | 62篇 |
农学 | 24篇 |
基础科学 | 2篇 |
86篇 | |
综合类 | 54篇 |
农作物 | 31篇 |
水产渔业 | 61篇 |
畜牧兽医 | 301篇 |
园艺 | 9篇 |
植物保护 | 53篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 10篇 |
2019年 | 4篇 |
2018年 | 18篇 |
2017年 | 16篇 |
2016年 | 12篇 |
2015年 | 25篇 |
2014年 | 15篇 |
2013年 | 47篇 |
2012年 | 31篇 |
2011年 | 58篇 |
2010年 | 24篇 |
2009年 | 23篇 |
2008年 | 34篇 |
2007年 | 36篇 |
2006年 | 42篇 |
2005年 | 23篇 |
2004年 | 20篇 |
2003年 | 26篇 |
2002年 | 17篇 |
2001年 | 19篇 |
2000年 | 27篇 |
1999年 | 19篇 |
1998年 | 8篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 11篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1971年 | 4篇 |
1970年 | 3篇 |
1966年 | 1篇 |
排序方式: 共有683条查询结果,搜索用时 15 毫秒
671.
Surks HK Mochizuki N Kasai Y Georgescu SP Tang KM Ito M Lincoln TM Mendelsohn ME 《Science (New York, N.Y.)》1999,286(5444):1583-1587
Contraction and relaxation of smooth muscle are regulated by myosin light-chain kinase and myosin phosphatase through phosphorylation and dephosphorylation of myosin light chains. Cyclic guanosine monophosphate (cGMP)-dependent protein kinase Ialpha (cGKIalpha) mediates physiologic relaxation of vascular smooth muscle in response to nitric oxide and cGMP. It is shown here that cGKIalpha is targeted to the smooth muscle cell contractile apparatus by a leucine zipper interaction with the myosin-binding subunit (MBS) of myosin phosphatase. Uncoupling of the cGKIalpha-MBS interaction prevents cGMP-dependent dephosphorylation of myosin light chain, demonstrating that this interaction is essential to the regulation of vascular smooth muscle cell tone. 相似文献
672.
R. A. Bustomi Rosadi Afandi Masateru Senge Kengo Ito John T. Adomako 《Paddy and Water Environment》2005,3(4):219-223
The objective of this research was to investigate the critical water content (θ
c) and water stress coefficient (K
s) of soybean plant under deficit irrigation. This research was conducted in a plastic house at the University of Lampung,
Sumatra in Indonesia from June to September 2000. The water deficit levels were 0–20%, 20–40%, 40–60%, 60–80%, and 80–100%
of available water (AW) deficit, arranged in Randomized Completely Block (RCB) design with four replications. The results
showed that the soybean plant started to experience stress from week IV within 40–60% of AW deficit. The fraction of total
available water (TAW) that the crop can extract from the root zone without suffering water stress (p) was 0.5 and θc was 0.305 m3 m−3. The values of K
s at p=0.5 were 0.78, 0.86, 0.78, and 0.71 from week IV to week VII, respectively. The optimum yield of soybean plant with the highest
yield efficiency was reached at 40–60% of AW deficit with an average K
s value of 0.78; this level of deficit irrigation could conserve about 10% of the irrigation. The optimum yield of soybean
plant was 7.9 g/pot and crop water requirement was 372 mm. 相似文献
673.
High-speed melt spinning of syndiotactic polystyrene was carried out using high and low molecular weight polymers, HMs-PS and LMs-PS, at the throughput rates of 3 and 6 g/min. The effect of take-up velocity on the structure and properties of as-spun fibers
was investigated. Wide angle X-ray diffraction (WAXD) patterns of the as-spun fibers revealed that the orientation-induced
crystallization started to occur at the take-up velocities of 2–3 km/min. The crystal modification wasα-form. Birefringence of as-spun fibers showed negative value, and the absolute value of birefringence increased with an increase
in the take-up velocity. The cold crystallization temperature analyzed through the differential scanning calorimetry (DSC)
decreased with an increase in the take-up velocity in the low speed region, whereas as the melting temperature increased after
the on-set of orientation-induced crystallization. It was found that the fiber structure development proceeded from lower
take-up velocities when the spinning conditions of higher molecular weight and lower throughput rate were adopted. The highest
tensile modulus of 6.5 GPa was obtained for the fibers prepared at the spinning conditions of LMs-PS, 6 g/min and 5 km/min, whereas the highest tensile strength of 160 MPa was obtained for the HMs-PS fibers at the take-up velocity of 2 km/min. Elongation at break of as-spun fibers showed an abrupt increase, which was
regarded as the brittle-ductile transition, in the low speed region, and subsequently decreased with an increase in the take-up
velocity. There was a universal relation between the thermal and mechanical properties of as-spun fibers and the birefringence
of as-spun fibers when the fibers were still amorphous. The orientation-induced crystallization was found to start when the
birefringence reached — 0.02. After the starting of the orientation-induced crystallization, thermal and mechanical properties
of as-spun fibers with similar level of birefringence varied significantly depending on the processing conditions. 相似文献
674.
Shinichi Nishimura Sang-bong Lee Kengo Ito Masateru Senge 《Paddy and Water Environment》2005,3(3):149-154
In the absence of a reservoir on the downstream side, a river flow that increases temporarily by rainfall cannot be stored
and discharged apart from requirements in a command area. This unused water (excess water) occurs to some extent even in a
drought year and making effective use of this supply is considered as one of the countermeasures for water shortage. Setting
up a regulating reservoir on the upstream side of head works is regarded as one of the methods for making effective use of
excess water. The inflow to the river and water delivery loss occurred from rainfall are stored in the regulating reservoir
and supplied to the command area on the downstream side as agricultural water. An operational method for the regulating reservoir
to effectively utilize the excess water was examined for a canal system by simulation. In an investigated area, there was
excess water even in drought years, and making use of it through the regulating reservoir whose capacity is smaller compared
to that of a dam can become one of the countermeasures for the drought period. The simulation in this study could estimate
quantitatively the effect of the regulating reservoir to make the excess water effective. 相似文献
675.
Hydrolyzable tannins, including ellagitannins, occur in foods such as berries and nuts. Various biological activities, including antioxidant, antiviral, and antitumor activities, have been noted and reported for ellagitannins, but the absorption and metabolism of purified ellagitannins are poorly understood. We describe herein the characterization of urinary and intestinal microbial metabolites in rats after the ingestion of ellagitannins. Urine samples were collected after oral administration of ellagitannins such as geraniin ( 1), corilagin ( 2), and their related polyphenols. The suspension of rat intestinal microflora was anaerobically incubated with ellagitannins. Each sample was separated by column chromatography and/or preparative HPLC to give seven metabolites, M1- M7. The structures of these metabolites were determined on the basis of spectroscopic data and chemical evidence. These compounds, except for M1, were characterized as ellagitannin metabolites for the first time. Furthermore, among four major metabolites ( M1- M4) in urine, M2 showed an antioxidant activity comparable to intact geraniin and related polyphenols. 相似文献
676.
Shimoda H Tanaka J Kikuchi M Fukuda T Ito H Hatano T Yoshida T 《Journal of agricultural and food chemistry》2008,56(12):4444-4449
The polyphenol-rich fraction (WP, 45% polyphenol) prepared from the kernel pellicles of walnuts was assessed for its hepatoprotective effect in mice. A single oral administration of WP (200 mg/kg) significantly suppressed serum glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) elevation in liver injury induced by carbon tetrachloride (CCl 4), while it did not suppress d-galactosamine (GalN)-induced liver injury. In order to identify the active principles in WP, we examined individual constituents for the protective effect on cell damage induced by CCl 4 and d-GalN in primary cultured rat hepatocytes. WP was effective against both CCl 4- and d-GalN-induced hepatocyte damages. Among the constituents, only ellagitannins with a galloylated glucopyranose core, such as tellimagrandins I, II, and rugosin C, suppressed CCl 4-induced hepatocyte damage significantly. Most of the ellagitannins including tellimagrandin I and 2,3- O-hexahydroxydiphenoylglucose exhibited remarkable inhibitory effect against d-GalN-induced damage. Telliamgrandin I especially completely suppressed both CCl 4- and d-GalN-induced cell damage, and thus is likely the principal constituent for the hepatoprotective effect of WP. 相似文献
677.
Ito A Hattori M Yoshida T Watanabe A Sato R Takahashi K 《Journal of agricultural and food chemistry》2006,54(26):10191-10196
The binding of an amino acid, glycine (Gly), alanine (Ala), epsilon-aminocaproic acid (-AC), monosodium glutamate (GluNa), or lysine (Lys), to starch was examined by a biomolecular interaction analyzer (IAsys). A starch sample (ATS) hydrolyzed to an extent of 1% hydrolysis rate with 15% sulfuric acid was used as a model starch for the binding examination. The reducing end of ATS was oxidized by the Somogyi reagent, and the conversion of the reducing end to the carboxyl group of ATS was confirmed by a carboxylic acid fluorescence labeling reagent. The oxidized ATS was immobilized to the amino group of a sensor cuvette by using water-soluble carbodiimide and N-hydroxysuccinimide through an amide bond. The IAsys examination showed that Gly, Ala, and epsilon-AC scarcely bound to the immobilized starch chains but that GluNa and Lys favorably bound with their increasing concentrations. The relative binding index (RBI) of each amino acid was defined by the ratio of the slope of the linear regression equation between the binding response and the concentration for each amino acid to that for Gly. Because the relationships between the RBI and the pasting characteristics (pasting temperature, peak viscosity, breakdown, and swelling index) could each be expressed by a linear regression equation with a high correlation coefficient, it is concluded that the regulation of the pasting behavior of starch with an amino acid is caused by binding of the amino acid to the starch chains. 相似文献
678.
Takeshi Ito Yudai Iino Shizuko Nakai Shiro Itoi Haruo Sugita Noriyuki Takai 《Fisheries Science》2018,84(4):627-640
The early life history of girellid fishes in Japanese waters is unclear, and little is known about their species-specific reproductive strategies. We examined seasonal changes of distribution patterns for settlement-stage juveniles of Girella punctata and Girella leonina on the rocky shore in the regions of Kanto and Izu, Japan, to infer the influence of the Kuroshio Current on their reproduction. We collected 813 settlement-stage juveniles mainly in Sagami Bay and genetically identified the species. The juveniles of G. punctata were collected on the rocky shore in Sagami Bay during April to August, with the abundant catch in May and June. Thus, we infer that juvenile G. punctata ubiquitously inhabit the rocky shore in the area in spring and summer. By contrast, juveniles of G. leonina were rarely collected in Sagami Bay, with a total catch of only 66. Notably, no juveniles were collected during the wintertime in Sagami Bay, although an abundant catch of G. leonina had been previously reported for Sagami Nada off Sagami Bay during January to March. This clear-cut difference between the areas likely reflects the difference in proximity to the path of the Kuroshio Current. We expect that the Kuroshio Current strongly influences the reproductive success of G. leonina. 相似文献
679.
The association between planktonic larval and benthic stages of Manila clam Ruditapes philippinarum and factors determining successful recruitment were studied in Akkeshi-ko estuary and Akkeshi Bay, Hokkaido, northern Japan. The field study showed that planktonic larvae were localized mainly in the bay after dispersal from the estuary and recruitment to the estuarine fishing grounds was not always successful. A numerical analysis suggested that estuarine circulation transported tracers, used to simulate planktonic larva, from the estuary to the bay but the number of returning tracers varied depending on the river discharge and wind direction. The planktonic larvae were affected by unsuitable conditions for survival in the estuary, such as high turbidity. We conclude that most larvae develop within the bay, where conditions are more saline and less turbid, and that although return to the estuary is essential for recruitment, it is not necessarily related to the abundance of larvae. 相似文献
680.
The effect of pelleting on in situ rumen degradability of compound feed containing brown rice for dairy cows
下载免费PDF全文
![点击此处可从《Animal Science Journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Shin‐ichi Tagawa Norio Yoshida Yukihiro Iino Ken‐ichi Horiguchi Toshiyoshi Takahashi Maria Watanabe Kei Takemura Syuhei Ito Toyoji Mikami 《Animal Science Journal》2017,88(1):185-189
This study was conducted to determine the effect of pelleting on in situ dry matter degradability of pelleted compound feed containing brown rice for dairy cows. Mash feed of the same composition was used as a control and the in situ study was conducted using three non‐lactating Holstein steers fitted with a rumen cannula. The feeds contained 32.3% brown rice, 19.4% rapeseed meal, 11.4% wheat bran and 10.6% soybean meal (fresh weight basis). Except for moisture content, the chemical composition of the feed was not affected by pelleting. In situ dry matter disappearance of the feed increased from 0 to 2 h and after 72 h of incubation with pellet processing. Integration of the dry matter disappearance values over time revealed that degradability parameter a (soluble fraction) increased with pellet processing, whereas parameter b (potentially degradable fraction) decreased. Parameter c (fractional rate of degradation) and effective degradability (5% passage rate) were not affected by pellet processing. We concluded that pellet processing promotes rumen degradability at early incubation hours when the pelleted feed contains brown rice. 相似文献