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991.
P. K. O'Connor B. Reich M. A. Sheridan 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1993,163(5):427-431
Rainbow trout were used to characterize the direct influence of growth hormone on hepatic lipid mobilization in vitro. Liver was removed from fish fasted 72 h, sliced into 1-mm3 pieces and incubated in Hanks' medium containing ovine or salmon growth hormone (0.28 ng·ml-1–28 g·ml-1). Lipid mobilization, resulting from triacylglycerol hydrolysis, was evaluated by fatty acid and glycerol release into culture medium. Control rates of fatty acid release and glycerol release were 0.95±0.16 (mean ± SE) and 0.88±0.28 mol·l-1·mg fresh weight, respectively. Both ovine growth hormone (28 ng·ml-1) and salmon growth hormone (28 ng·ml-1) stimulated fatty acid release into culture medium, increasing rates by 112% and 97%, respectively, during the course of a 24-h incubation. Glycerol release was similarly augmented by growth hormone treatment. Growth hormone-stimulated metabolite release became evident within 12 h and persisted for up to 72 h. The presence of amino acids in the culture medium potentiated the lipolytic action of growth hormone. Ovine growth hormone (28 ng·ml-1) in the presence of amino acids stimulated a 53% increase in fatty acid, and a 108% increase in glycerol, release over rates observed in the absence of amino acids. Salmon growth hormone (28 ng·ml-1) in the presence of amino acids stimulated a 53% increase in fatty acid, and a 44% increase in glycerol, release over rates observed in the absence of amino acids. Ovine growth hormone (28 ng·ml-1) also stimulated gluconeogenesis, as indicated by a 75% increase in phosphoenolpyruvate carboxykinase activity in liver pieces incubated in the presence of amino acids. These results indicate that growth hormone directly stimulates lipid breakdown in the liver of trout and that amino acids potentiate growth hormone-stimulated lipolysis.Abbreviations AA
amino acid(s)
- dGDP
deoxy-guanosine diphosphate
-
ED
50
50% effective dose
- FA
fatty acid(s)
- fw
fesh weight
- GH
growth hormone
- Hepes
4-(2-hydroxyethyl)-1-piperazineethanesulphonic acid
- MS-222
tricaine methanesulfonate
- MEM
minimum essential medium
- oGH
ovine growth hormone
- PEPCK
phosphoenolpyruvate carboxykinase
- PKc
protein kinase C
- rpm
revolutions per minute
- sGH
salmon growth hormone
- TG
triacylglycerol
- w/v
weight per volume
This paper was presented in abstract form at the Annual Meeting of the American Society of Zoologists, Dec. 26–30, 1991, Atlanta, GA 相似文献
992.
E. A. Santos R. Keller 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1993,163(5):374-379
The effects of glutamate, aspartate, glycine, proline, alanine, taurine, glycerol, glucose and lactate injections on the haemolymph levels of the crustancean hyperglycemic hormone and/or glucose and lactate in the shore crab, Carcinus maenas, were investigated. Only glucose and lactate caused significant changes of hyperglycaemic hormone levels. Glucose injections resulted in a drop of both hormone and lactate, while lactate had an opposite effect, i.e. it raised both crustacean hormone and glucose levels. The results suggest that during increases in glycolytic flux, lactate may cause a release of hormone by a positive feedback mechanism. The hormone would then stimulate glycogenolysis, thus increasing glucose availability. If more glucose is released than is metabolized, excess glucose may leak from the cells and suppress crustancean hyperglycemic hormone release from the X-organ/sinus gland complex by negative feedback.Abbreviations ABTS
2,2-azino-bis (3-ethylbenzthiazoline sulphonic acid)
- ANOVA
one-way analysis of variance
- BSA
bovine serum albumin
- BW
body weight
- CHH
crustacean hyperglycemic hormone
- ELISA
cnzyme-liked immunosorbent assay
- GIH
gonadinhibiting hormone
- IgG
immunoglobin G
- MIH
moult-inhibiting hormone
- MTGXO
medulla terminalis X-organ
- PB
sodium phosphate buffer
- PBS
phosphate buffered saline
- Pi
inorganic phosphate
- XO-SG
X-organ-sinus gland complex 相似文献
993.
Rosemary S. Gray David P. Muehleisen Eva J. Katahira Walter E. Bollenbacher 《Cellular and molecular neurobiology》1993,13(1):39-58
1. | A 28-kDa peptide from the brain of the tobacco hornworm,Manduca sexta, was purifiedvia HPLC. The peptide copurified with the insect neurohormone, prothoracicotropic hormone (PTTH), through two HPLC columns. |
2. | Immunocyctochemistry using polyclonal antibodies against the 28-kDa peptide revealed that the peptide was produced in the same protocerebral neurons that produce PTTH. Western blot analysis demonstrated that the 28-kDa peptide and big PTTH are different molecules. |
3. | A PTTHin vitro bioassay indicated that despite having chromatographic properties similar to those of big PTTH and being produced by the same neurons, the 28-kDa peptide did not have PTTH activity. |
4. | Amino acid sequence analysis yielded a 27 N-terminal amino acid sequence that had no similarity with known peptides. |
5. | Immunocytochemical studies revealed that the 28-kDa peptide is present as early as 30% embryonic development and is absent by adult eclosion. This is in contrast to big PTTH, which is expressed throughout theManduca life cycle. |
6. | These data suggest that the 28-kDa peptide is another secretory phenotype of the lateral neurosecretory cell group III (L-NSC III) which may have functions distinct from those for big PTTH or may act synergistically with big PTTH. |
994.
Effects of light and temperature on gibberellin (GA)-induced seed germination were studied in Arabidopsis thaliana (L.) Heynh. with the use of GA-deficient ( gal ) mutants, mutants with a strongly reduced sensitivity to GA ( gai ) and with the recombinant gai/gal . Seeds of the gal mutant did not germinate in the absence of exogenous GAs, neither in darkness, nor in light, indicating that GAs are absolutely required for germination of this species. Wild-type and gai seeds did not always require applied GAs in light. The conclusion that light stimulates GA biosynthesis was strengthened by the antagonistic action of tetcyclacis, an inhibitor of GA biosynthesis. In wild-type, gal and gai/gal seeds light lowered the GA requirement, which can be interpreted as an increase in sensitivity to GAs. In gai and gai/gal seeds light became effective only after dormancy was broken by either a chilling treatment of one week or a dry after-ripening period at 2°C during some months. The present genetic and physiological evidence strongly suggests that temperature regulates the responsiveness to light in A. thaliana seeds. The responsiveness increases during dormancy breaking, whereas the opposite occurs during induction of dormancy (8 days at 15°C pre-incubation). Since light stimulates the synthesis of GAs as well as the responsiveness to GAs, temperature-induced changes in dormancy may indirectly change the capacities to synthesize GAs and to respond to GAs. GA sensitivity is also directly controlled by temperature. It is concluded that both GA biosynthesis and sensitivity to GAs are not the primary controlling factors in dormancy, but are essential for germination. 相似文献
995.
E. J. Eisen M. Fortman W. Y. Chen J. J. Kopchick 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1993,87(1-2):161-169
The effects of a high-growth genetic background on the growth of mice hemizygous for one of two growth hormone transgenes were examined. Male mice hemizygous for wild-type (W) and dwarf mutant (M) bovine growth hormone (bGH) transgenes were crossed with females of a high-growth selected (S) and control (C) line as follows: W x S, W x C, M x S and M x C. Body weights of progeny were recorded weekly from 2 to 10 weeks of age. F1 progeny were classified as carriers (P) or non-carriers (N) of the transgene by assaying tail DNA for bGH using the polymerase chain reaction and agarose gel electrophoresis. A deficiency in the number of f1 progeny carrying the W (P<0.05) and M (P<0.01) bGH transgene was most likely due to differential prenatal and early postnatal mortality. Bodyweight means of wild-type transgenic mice were larger (P < 0.05) than those of non-transgenic littermates by 3 weeks of age in a C background in contrast to 5 weeks in S. The wild-type bGH transgene increased adult body weights more in the C (155%) than in the S (136%) background, indicating transgene expression by selection background interaction (P < 0.05). However, the growth response to the wild-type transgene in the S background was still large. The dwarf mutant transgene had a greater effect on growth reduction in the S (70%) than in the C (84%) background, thus causing transgene expression by selection background interaction (P < 0.05). Gender by wild-type transgene effect interactions (P < 0.001) for adult body weight were caused by the transgene reducing the gender difference for body weight in C and eliminating it in S. The dwarf mutant caused a larger negative effect on growth in males than in females, resulting in a gender by dwarf mutant transgene interaction (P < 0.001) for adult body weights. Results indicate that the effect of a GH transgene on growth can be affected both by a high-growth genetic background and the gender of progeny. 相似文献
996.
Jacek Najda Jan Gmiński Marian Dróżdż Franciszek Zych 《Biological trace element research》1993,37(2-3):101-106
The influence of silicon-treatment on the levels of TSH and thyroid hormones was studied in rats. Concentrations of thyrotropin
(TSH), triiodothyronine (T3), and thyroxine (T4) were estimated in sera of rats receiving per os a soluble silicon compound—sodium metasilicate nonahydrate (Na2SiO3·9H2O), dissolved in the animals' drinking water. An increase in the TSH level in the tested group was observed, without statistically
significant differences in T3 and T4 concentrations between the two groups of animals. The results provide evidence for the influence of silicon on the endocrine
balance. They could also prove that this chemical element is capable of modifying the rate of some hormones' synthesis. 相似文献
997.
Morphometric studies were made on corpora allata of the cockroach Diploptera punctata from animals in which increasing gland size is not coupled to hormone synthesis (ovariectomized mated females; last-instar larvae) and in which gland size is coupled to hormone synthesis (normal mated and virgin females; penultimate-instar larvae). Cell number, gland volume, and juvenile hormone synthesis were measured. From electron micrographs, nuclear, cytoplasmic, and extracellular volumes; and cell membrane area were calculated; and fine structure described. Low-activity glands of ovariectomized mated females resembled high-activity glands from mated females in high cell number, large overall and cytoplasmic volume, and low nuclear-cytoplasmic ratio; they differed in having organelles typical of low-activity glands, mitochondria with dense matrices and large whorls of smooth endoplasmic reticulum. Inactive lastinstar larval glands resembled mated ovariectomized, female glands in increased cell number and organelles characteristic of inactive glands; however, their nuclearcytoplasmic volume ratio was much higher. Penultimate cytoplasmic volume ratio was much higher. Penultimate larval glands with high activity per cell resembled active glands of normal mated females. Ovariectomy did not change morphometric parameters of virgin female glands; thus mating results in increase in size of adult female glands whereas the growing ovary is needed for changes in mitochondria and endoplasmic reticulum associated with high juvenile hormone synthesis. 相似文献
998.
Simon Y. C. Wong Geoffrey R. Guile Thomas W. Rademacher Raymond A. Dwek 《Glycoconjugate journal》1993,10(3):227-234
Glycopeptides can be valuable tools in determining the influence of carbohydrate moieties on the intrinsic properties of glycoproteins. However, glycopeptides of sufficient quantity and purity are as yet not readily available from biological sources. The chemical coupling of a -glycosylamino group of an unprotected carbohydrate with an activated aspartic acid residue of an unprotected peptide is a simple method for synthesizing asparagine-linked glycopeptides. In this report we demonstrate that the use of this method is not restricted to -glycosylamines of simple monosaccharides or short aspartic acid-containing pentapeptides. This is illustrated by the syntheses of several glycopentapeptides containingN,N-diacetylchitobiose, a glutamine-linked glycopentapeptide containing a biantennary complex oligosaccharide, and glycosylated variants of two analogs of a polypeptide hormone, atriopeptin, containingN,N-diacetylchitobiose.Abbreviations Ac
acetyl
- Bzl
benzyl
- DMF
dimethylformamide
- Fmoc
9-fluorenylmethoxycarbonyl
- Fuc
fucose
- Gal
galactose
- GlcNAc
N-acetylglucosamine
- HBTU
O-benzotriazol-1-yl-N,N,N,N-tetramethyluroniumhexa-fluorophosphate
- HOBt
1-hydroxybenzotriazole
- Man
mannose
-
m/z
mass/charge
- NMR
nuclear magnetic resonance
- Xyl
xylose
- Z
benzyloxycarbonyl; unless otherwise specified, amino acids are abbreviated using their one-letter codes. 相似文献
999.
在繁殖季节,将哺乳动物促性腺激素注射到性腺正在成熟文昌鱼体内,注射36小时后,检查促性腺激素的生理效应,结果表明这两种激素均有效地诱发卵母细胞成熟和产卵。从而认为雌性文昌鱼的生殖活动,像脊椎动物一样,可能受促性腺激素的调控。 相似文献
1000.
The solution structure of melanoma growth stimulating activity (MGSA) has been investigated using proton NMR spectroscopy. Sequential resonance assignments have been carried out, and elements of secondary structure have been identified on the basis of NOE, coupling constant, chemical shift, and amide proton exchange data. Long-range NOEs have established that MGSA is a dimer in solution. The secondary structure and dimer interface of MGSA appear to be similar to those found previously for the homologous chemokine interleukin-8 [Clore et al. (1990) Biochemistry 29, 1689-1696]. The MGSA monomer contains a three stranded anti-parallel β-sheet arranged in a ‘Greek-key’ conformation, and a C-terininal -helix (residues 58 69). 相似文献