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661.
L L Anderson J J Ford J Klindt J R Molina W W Vale J Rivier 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1991,196(2):194-202
Control of growth hormone (GH) and prolactin (PRL) release was investigated in hypophysial stalk-transected (HST) and stalk-intact pigs by determining the effects of analogs of GH-releasing factors (GHRF), somatostatin (SRIF), arginine, thyrotropin-releasing hormone, alpha-methyl-rho-tyrosine, and haloperidol. HST and control gilts were challenged with intravenous injections of human pancreatic GHRF(1-40)OH, thyrotropin-releasing hormone, and analogs of rat hypothalamic GHRF. HST animals remained acutely responsive to GHRF by releasing 2-fold greater quantities of GH than seen in controls. This occurred in spite of a 38% reduction in pituitary gland weight and a 32 and 55% decrease in GH concentration and total content. During SRIF infusion, GH remained at similar basal concentrations in HST and control gilts, but increased immediately after stopping SRIF infusion only in the controls. Releasable pituitary GH appears to accumulate during SRIF infusion. GHRF given during SRIF infusion caused a 2-fold greater release of GH than seen in animals receiving only GHRF. Arginine increased (P less than 0.05) GH release in controls, but not in HST gilts, which suggests that it acts through the central nervous system. Basal PRL concentrations were greater (P less than 0.05) in HST gilts than in control gilts. TRH acutely elevated circulating PRL (P less than 0.001) in HST gilts, suggesting that it acts directly on the pituitary gland. Haloperidol, a dopamine receptor antagonist, increased circulating PRL in controls but not in HST animals. alpha-Methyl-rho-tyrosine did not consistently increase circulating PRL, however, suggesting that it did not sufficiently alter turnover rate of the tyrosine hydroxylase pool. The results indicate that the isolated pituitary after HST remains acutely responsive to hypothalamic releasing and inhibiting factors for both GH and PRL release in the pig. 相似文献
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While the concept of a nonsteroidal entity of gonadal origin, which specifically regulates FSH secretion, was proposed over 50 years ago, problems linked to the assay, isolation and characterization of this protein have only recently been solved. The structure of inhibin from follicular fluid origin has been established as a heterodimer consisting of two subunits (alpha and beta) linked by disulfide bridges. The development of antisera specifically directed against the N-terminus part of the alpha-chain of inhibin has allowed the measurement of plasma levels of inhibin, as well as the evaluation of the biological effect of removal of endogenous inhibin. These studies have demonstrated age-related changes in the circulating levels of inhibin in the female rat and support the hypothesis that inhibin represents an important modulator of FSH secretion in this species. 相似文献
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667.
Ana Flávia do Vale Neves Machado Cleonice Maria Cardoso Lobato Rafael Rodrigues Gusmão Luciano Fogaça de Assis Montag Bruno Silveira Prudente 《Zeitschrift fur angewandte Ichthyologie》2020,36(5):745-747
The length-weight relationship is important for the study of populational dynamics. This study aimed to describe the length-weight relationships (LWR) of 11 fish species sampled on 18 streams of the Capim river basin on eastern Amazon. Specimens were captured in 2014, 2015 and 2017, using sieve nets with 2 mm of mesh size. Fixed specimens were fixed in 10% formalin and conserved in alcohol 70%, measured for standard length (SL, 0.1 cm) and total weight (W, 0.01 g). The 11 species analysed were: Hemigrammus bellottii, Hemigrammus ocellifer, Hyphessobrycon heterorhabdus, Iguanodectes rachovii, Copella arnoldi, Nannostomus trifasciatus, Apistogramma regani, Apistogramma agassizii, Gymnorhamphichthys rondoni, Hypopygus lepturus, Anablepsoides urophthalmus. 相似文献
668.
Carmen Vale Eva Alonso Juan A. Rubiolo Mercedes R. Vieytes Frank M. LaFerla Lydia Giménez-Llort Luis M. Botana 《Cellular and molecular neurobiology》2010,30(4):577-590
Advances in transgenic technology as well as in the genetics of Alzheimer disease (AD) have allowed the establishment of animal
models that reproduce amyloid-beta plaques and neurofibrillary tangles, the main pathological hallmarks of AD. Among these
models, 3xTg-AD mice harboring PS1
M146V, APP
Swe and tau
P301L human transgenes provided the model that most closely mimics human AD features. Although cortical cultures from 3xTg-AD mice
have been shown to present disturbances in intracellular [Ca2+] homeostasis, the development of AD pathology in vitro has not been previously evaluated. In the current work, we determined
the temporal profile for amyloid precursor protein, amyloid-β and tau expression in primary cortical cultures from 3xTg-AD
mice. Immunocytochemistry and Western blot analysis showed an increased expression of these proteins as well as several phosphorylated
tau isoforms with time in culture. Alterations in calcium homeostasis and cholinergic and glutamatergic responses were also
observed early in vitro. Thus, 3x-TgAD cortical neurons in vitro provide an exceptional tool to investigate pharmacological
approaches as well as the cellular basis for AD and related diseases. 相似文献
669.
670.
G C Doelle R M Evans A N Alexander J Rivier W Vale D Rabin 《Hormones et métabolisme》1986,18(3):201-202
The agonist analogue of gonadotropin-releasing hormone (GnRH), [(imBz1)-D-His6,Pro9-NEt]GnRH, has a potency 200 times that of the native hormone in vitro. In single dose studies in man, this analogue resulted in 2- to 4-fold elevation of LH and FSH, and demonstrated a prolonged duration of activity. [(imBz1)-D-His6,Pro9-NEt]GnRH appears to be safe and, as with other analogues of GnRH, may have application to clinical medicine. 相似文献