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排序方式: 共有490条查询结果,搜索用时 31 毫秒
71.
Kawashima C Matsui M Shimizu T Kida K Miyamoto A 《The Journal of reproduction and development》2012,58(1):10-16
During recent decades, milk production per cow has increased drastically due to improved management, nutrition, and genetic selection; however, the reproductive performance of high-producing dairy cows has been declining. One of the factors responsible for this low reproductive performance is negative energy balance (NEB). NEB affects the onset of first ovulation in early postpartum cows. It is generally accepted that early first ovulation positively relates to the resumption of normal ovarian function, first service, and conception rate in dairy cows. Hence, delayed first ovulation has a negative impact on subsequent fertility. The metabolic condition of cows in NEB shifts to catabolic metabolism, which in turn causes increased plasma growth hormone and non-esterified fatty acid concentrations and decreased plasma insulin-like growth factor-1, insulin, and glucose concentrations. On the other hand, plasma β-carotene concentrations decrease throughout the dry period and reach their nadir in about the first week postpartum, and this change reflects energy balance during the peripartum period. β-Carotene plays a role independently of vitamin A in the reproductive performance of dairy cows, and the positive relationship between supplemental β-carotene and reproductive function has been demonstrated in many studies during the past decades. However, β-carotene content in corn silage, which is a popular main feed in high-producing dairy cows, is very low. This review describes nutritional factors related to ovulation during the first follicular wave postpartum in dairy cows. 相似文献
72.
Yutaka SUZUKI Sang‐Houn SONG Katsuyoshi SATO Kyoung‐Ha SO Astrid ARDIYANTI Shun KITAYAMA Yeon‐Hee HONG Sung‐Dae LEE Ki‐Choon CHOI Akihiko HAGINO Kazuo KATOH Sang‐gun ROH 《Animal Science Journal》2012,83(3):263-267
Accumulating data suggest a relationship between chemerin and energy metabolism. Our group previously described gene cloning, expression analysis and the regulatory mechanism of chemerin and its own receptor in mice and cattle. The objective of the present study was to investigate the physiological effect of chemerin on endocrine changes and energy metabolism in sheep using a biologically stable chemerin analog. The chemerin analog was intravenously administrated (100 or 500 µg/head) to sheep, and plasma insulin and metabolites (glucose, nonesterified fatty acids (NEFA), triglyceride, total cholesterol and high‐density lipoprotein (HDL) cholesterol) were analyzed. The chemerin analog dramatically increased the insulin levels, and glucose levels were decreased. NEFA levels were slightly decreased at 20 min but then increased gradually from 60 to 180 min after analog administration. In addition, injection of the chemerin analog immediately increased triglyceride and total cholesterol but not HDL levels. These results suggested that chemerin analog regulated insulin secretion related to glucose metabolism and the release of triglycerides in sheep in vivo. This study provides new information about endocrine and metabolic changes in response to chemerin in sheep. 相似文献
73.
Both stem and crown mass affect tree resistance to uprooting 总被引:1,自引:0,他引:1
Tsutomu Urata Masato Shibuya Akio Koizumi Hiroyuki Torita JooYoung Cha 《Journal of Forest Research》2012,17(1):65-71
To examine the hypothesis that both stem and crown mass affect the resistance of a tree to uprooting and that tree resistance
increases with increasing crown mass, we conducted tree-pulling experiments on three Picea glehnii plantations (stands A, B, and C: 27–32 years old) that differed in tree density and slenderness ratio. Allometries between
crown and stem masses and between the critical uprooting moment and stem mass differed significantly among the three stands,
with the crown mass and critical moment significantly larger in stand C than in stands A or B, despite the same stem mass.
These results quantitatively verified our hypothesis. Allometries between crown and stem masses and between critical uprooting
moment and stem mass were highly significant in each stand but were stand specific. Therefore, these allometries can be used
to estimate tree resistance to uprooting in a given stand but not for data compiled from stands of various conditions and
tree shapes. The allometry between critical moment and aboveground mass did not differ among the three Picea stands; thus, it is not stand specific and is generally appropriate to use for estimating tree resistance. To increase tree
resistance to uprooting, we recommend light management for Picea glehnii plantations and probably other coniferous plantations as well. 相似文献
74.
75.
Rasoul KOWSAR Nina HAMBRUCH Jinghui LIU Takashi SHIMIZU Christiane PFARRER Akio MIYAMOTO 《The Journal of reproduction and development》2013,59(5):470-478
This study aimed to investigate the role of epithelial cells in regulating innate
immunity in bovine oviduct epithelial cell (BOEC) culture. We studied the effect of
Escherichia coli lipopolysaccharide (LPS) and its interaction with
ovarian steroids, estradiol (E2) and progesterone (P4), and luteinizing hormone (LH) at
concentrations observed during the preovulatory period on immune responses in BOEC
culture. Immunohistochemistry of oviduct tissue showed intensive expression of Toll-like
receptor-4 (TLR-4) and TLR-2 in epithelial cells. A dose of 10 ng/ml LPS stimulated
TLR-4, cyclooxygenase-2 (COX-2), nuclear factor kappa
B inhibitor A (NFKBIA), interleukin 1β (IL-1β) and tumor
necrosis factor α (TNF-α) expression, indicating an early
pro-inflammatory response. A dose of 100 ng/ml LPS did not induce expression of these
genes but stimulated TLR-2, IL-10,IL-4
and microsomal prostaglandin E synthase-1 (mPGES-1) expression and PGE2
secretion, indicating an anti-inflammatory response. Ovarian steroids and LH completely
block LPS (10 ng/ml)-induced TLR-4, IL-1β and
TNF-α expression as well as LPS (100 ng/ml)-induced
TLR-2 expression. Taken together, this study suggests the existence of
an early signaling system to respond to infection in the BOEC. In addition, ovarian
steroids and LH may play a critical role in inducing homeostasis and in controlling
hyperactive pro-inflammatory responses detrimental to epithelial cells, sperm and the
embryo. 相似文献
76.
77.
Transgenic rice lines that include barley genes have increased tolerance to low iron availability in a calcareous paddy soil 总被引:2,自引:0,他引:2
78.
79.
Yasu-Taka AZUMA Sho SUZUKI Kazuhiro NISHIYAMA Taro YAMAGUCHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(4):622
Excessive stress response causes disability in social life. There are many diseases caused by stress, such as gastrointestinal motility disorders, depression, eating disorders, and cardiovascular diseases. Transient receptor potential (TRP) channels underlie non-selective cation currents and are downstream effectors of G protein-coupled receptors. Ca2+ influx is important for smooth muscle contraction, which is responsible for gastrointestinal motility. Little is known about the possible involvement of TRP channels in the gastrointestinal motility disorders due to stress. The purpose of this study was to measure the changes in gastrointestinal motility caused by stress and to elucidate the mechanism of these changes. The stress model used the water immersion restraint stress. Gastrointestinal motility, especially the ileum, was recorded responses to electric field stimulation (EFS) by isometric transducer. EFS-induced contraction was significantly reduced in the ileum of stressed mouse. Even under the conditions treated with atropine, EFS-induced contraction was significantly reduced in the ileum of stressed mouse. In addition, carbachol-induced, neurokinin A-induced, and substance P-induced contractions were all significantly reduced in the ileum of stressed mouse. Furthermore, the expression of TRPC3 was decreased in the ileum of stressed mouse. These results suggest that the gastrointestinal motility disorders due to stress is associated with specific non-selective cation channel. 相似文献
80.