全文获取类型
收费全文 | 443篇 |
免费 | 37篇 |
出版年
2022年 | 6篇 |
2021年 | 9篇 |
2020年 | 3篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 9篇 |
2015年 | 10篇 |
2014年 | 15篇 |
2013年 | 13篇 |
2012年 | 15篇 |
2011年 | 25篇 |
2010年 | 15篇 |
2009年 | 11篇 |
2008年 | 12篇 |
2007年 | 18篇 |
2006年 | 14篇 |
2005年 | 16篇 |
2004年 | 18篇 |
2003年 | 14篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 12篇 |
1999年 | 14篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1993年 | 5篇 |
1992年 | 11篇 |
1991年 | 13篇 |
1990年 | 9篇 |
1989年 | 16篇 |
1988年 | 4篇 |
1987年 | 12篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 3篇 |
1981年 | 9篇 |
1980年 | 3篇 |
1979年 | 7篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1974年 | 7篇 |
1973年 | 7篇 |
1972年 | 6篇 |
1970年 | 3篇 |
1969年 | 4篇 |
1967年 | 3篇 |
1966年 | 2篇 |
排序方式: 共有480条查询结果,搜索用时 15 毫秒
471.
472.
Density gradient ultracentrifugation of human serum high density lipoproteins (HDL) from both normolipemic males and females results in a distribution of HDL concentration versus subfraction hydrated density which has three maxima. Gradient gel electrophoresis of total HDL is characterized by three banding maxima, the positions of which suggest the presence of three particle size ranges: I. 10.8-12.0 nm, II. 9.7-10.7 nm, and III. 8.5-9.6 nm. Gradient gel electrophoresis of density gradient subfractions established an inverse relationship between particle size and particle hydrated density which was corroborated by electron microscopy and analytic ultracentrifugation. Comparison of male HDL from size ranges I, II, and III with female HDL from the same size ranges showed only small differences in the mean value of the peak F degrees 1.20 rate, size, molecular weight, protein weight percent, and weight protein/weight phospholipid. Major differences between males and females were seen in the relative amounts of HDL in density gradient subfractions 1-3 (size range I material) and 11-12 (size range III material); the percent total HDL in the group of subfractions 1-3 was greatly increased in female HDL while that of the group of subfractions 11-12 was increased in the male HDL. These studies indicate the presence of at least three major components in HDL instead of two (HDL2 and HDL3) and that peak F degrees 1.20 rate differences in HDL schlieren patterns between males and females are a function of the relative levels of these three components. 相似文献
473.
Stefania Pagliari Vladimir Vinarsky Fabiana Martino Ana Rubina Perestrelo Jorge Oliver De La Cruz Guido Caluori Jan Vrbsky Pamela Mozetic Antonio Pompeiano Andrea Zancla Sri Ganji Ranjani Petr Skladal Dan Kytyr Zbynk Zdrhal Gabriele Grassi Maurilio Sampaolesi Alberto Rainer Giancarlo Forte 《Cell death and differentiation》2021,28(4):1193
474.
Fuoco Natalia Langenfeld de Oliveira Rafael Guilen Marcelino Monica Yonashiro Stessuk Talita Sakalem Marna Eliana Medina Denis Aloisio Lopes Modotti Waldir Pereira Forte Andresa Ribeiro-Paes João Tadeu 《Molecular biology reports》2020,47(4):2475-2486
Molecular Biology Reports - Classical methods used for culture of adipose-derived mesenchymal stromal cells (ADSCs) use xenobiotic components, which may present a potential risk for biological... 相似文献
475.
476.
Ezrin-calpain I interactions in gastric parietal cells 总被引:5,自引:0,他引:5
477.
Leonard R. Forte David L. Carnes G. Allen Nickols Constantine S. Anast 《Journal of cellular biochemistry》1978,9(2):179-188
Rats fed a diet deficient in vitamin D were found to exhibit a refractory cyclic AMP response of kidney slices to parathyroid hormone and a marked decrease in membrane parathyroid hormone-dependent adenylate cyclase activity. Both the characteristic calcium deficiency (hypocalcemia) and secondary elevation of circulating parathyroid hormone appeared before the first noticeable decrease in hormone-dependent enzyme activity. After repletion of D-deficient rats with vitamin D2, we found that serum calcium and parathyroid hormone were both restored to normal levels before the depressed enzyme response to the hormone was reversed. Moreover, infusion of parathyroid hormone into vitamin D-replete rats led to a marked reduction in parathyroid hormone-dependent adenylate cyclase activity, which was partly restored to control level 3 hours after discontinuing the hormone infusion. Taken as a whole, this study suggests that the elevated endogenous parathyroid hormone in the vitamin D-deficient rat is involved in the “down-regulation” of renal cyclic AMP responsiveness to the hormone. However, these experiments do not rule out the possibility that calcium deficiency and/or vitamin D per se participate in the regulation of the renal cyclic AMP response to parathyroid hormone. 相似文献
478.
Zaquer Suzana Munhoz Costa-Ferro Fernanda de Borba Cunha Bruno Solano de Freitas Souza Marcos Maurício Tosta Leal Adelson Alves da Silva Telma Ingrid Borges de Bellis Kühn Andresa Forte Eliseo Joji Sekiya Milena Botelho Pereira Soares Ricardo Ribeiro dos Santos 《Cytotechnology》2014,66(2):193-199
Status epilepticus (SE) is a condition of persistent seizure that leads to brain damage and, frequently, to the establishment of chronic epilepsy. Cord blood is an important source of adult stem cells for the treatment of neurological disorders. The present study aimed to evaluate the effects of human umbilical cord blood mononuclear cells (HUCBC) transplanted into rats after induction of SE by the administration of lithium and pilocarpine chloride. Transplantation of HUCBC into epileptic rats protected against neuronal loss in the hippocampal subfields CA1, CA3 and in the hilus of the dentate gyrus, up to 300 days after SE induction. Moreover, transplanted rats had reduced frequency and duration of spontaneous recurrent seizures (SRS) 15, 120 and 300 days after the SE. Our study shows that HUCBC provide prominent antiepileptic and neuroprotective effects in the experimental model of epilepsy and reinforces that early interventions can protect the brain against the establishment of epilepsy. 相似文献
479.
Marcus B. S. Forte Marcio A. Mazutti Francisco Maugeri Filho Maria Isabel Rodrigues 《Biotechnology and Bioprocess Engineering》2011,16(6):1223-1230
This work investigates the adsorption of clavulanic acid using natural six cationic forms (Na+, Ca+2, Ba+2, Sr2+, K+, and Mg2+) of the X and NZ zeolites in a stirred tank reactor since the separation is an important step of the biomolecule production.
A mathematical model was proposed taking into account the transport of CA molecules from the liquid phase to the surface of
the adsorbent and after diffusion into the particles. The estimated kinetic and mass transfer parameters were used to evaluate
adsorption rates and mass transfer resistances involved in the separation of clavulanic acid from the broth. It has been shown
that mass-transfer phenomena were a limiting step in the clavulanic acid adsorption process and that the adsorption rate should
be considered to evaluate the system. Amongst the materials, the synthetic zeolite NaX was selected as the most appropriate
material to separate clavulanic acid because this material presented the highest values for the observed reaction rate, compensating
for the external mass transfer resistance. Modeling and simulation of clavulanic acid purification using the zeolite NaX showed
a satisfactory fitting of experimental data. The model was used to simulate the process and it was evaluated for its technical
and economical viability by comparisons considering the influence of the solid:liquid ratio on the adsorption equilibrium
time and on the hydrolysed mass of biomolecule. 相似文献
480.
L R Forte 《Regulatory peptides》1999,81(1-3):25-39
The guanylin family of bioactive peptides consists of three endogenous peptides, including guanylin, uroguanylin and lymphoguanylin, and one exogenous peptide toxin produced by enteric bacteria. These small cysteine-rich peptides activate cell-surface receptors, which have intrinsic guanylate cyclase activity, thus modulating cellular function via the intracellular second messenger, cyclic GMP. Membrane guanylate cyclase-C is an intestinal receptor for guanylin and uroguanylin that is responsible for stimulation of Cl- and HCO3- secretion into the intestinal lumen. Guanylin and uroguanylin are produced within the intestinal mucosa to serve in a paracrine mechanism for regulation of intestinal fluid and electrolyte secretion. Enteric bacteria secrete peptide toxin mimics of uroguanylin and guanylin that activate the intestinal receptors in an uncontrolled fashion to produce secretory diarrhea. Opossum kidney guanylate cyclase is a key receptor in the kidney that may be responsible for the diuretic and natriuretic actions of uroguanylin in vivo. Uroguanylin serves in an endocrine axis linking the intestine and kidney where its natriuretic and diuretic actions contribute to the maintenance of Na+ balance following oral ingestion of NaCl. Lymphoguanylin is highly expressed in the kidney and myocardium where this unique peptide may act locally to regulate cyclic GMP levels in target cells. Lymphoguanylin is also produced in cells of the lymphoid-immune system where other physiological functions may be influenced by intracellular cyclic GMP. Observations of nature are providing insights into cellular mechanisms involving guanylin peptides in intestinal diseases such as colon cancer and diarrhea and in chronic renal diseases or cardiac disorders such as congestive heart failure where guanylin and/or uroguanylin levels in the circulation and/or urine are pathologically elevated. Guanylin peptides are clearly involved in the regulation of salt and water homeostasis, but new findings indicate that these novel peptides have diverse physiological roles in addition to those previously documented for control of intestinal and renal function. 相似文献