全文获取类型
收费全文 | 1891篇 |
免费 | 81篇 |
国内免费 | 1篇 |
出版年
2024年 | 4篇 |
2023年 | 16篇 |
2022年 | 15篇 |
2021年 | 65篇 |
2020年 | 54篇 |
2019年 | 55篇 |
2018年 | 51篇 |
2017年 | 63篇 |
2016年 | 81篇 |
2015年 | 86篇 |
2014年 | 112篇 |
2013年 | 136篇 |
2012年 | 150篇 |
2011年 | 149篇 |
2010年 | 97篇 |
2009年 | 75篇 |
2008年 | 107篇 |
2007年 | 113篇 |
2006年 | 94篇 |
2005年 | 83篇 |
2004年 | 74篇 |
2003年 | 62篇 |
2002年 | 53篇 |
2001年 | 18篇 |
2000年 | 17篇 |
1999年 | 18篇 |
1998年 | 14篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1977年 | 3篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1973年 | 10篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1970年 | 5篇 |
排序方式: 共有1973条查询结果,搜索用时 15 毫秒
101.
The simple and effective choice for treatment of chronic calcaneal osteomyelitis: neurocutaneous flaps 总被引:9,自引:0,他引:9
Yildirim S Gideroğlu K Aköz T 《Plastic and reconstructive surgery》2003,111(2):753-60; discussion 761-2
The authors describe their experience with the use of distally based saphenous and sural neurofasciocutaneous flaps for the treatment of calcaneal osteomyelitis in nine cases. Aggressive débridement of all nonviable and poorly vascularized tissue and coverage with a distally based neurofasciocutaneous flap were coupled with a thorough antibiotic course in all cases. The deepithelized peripheral parts of all flaps were buried in the bone cavities after bone débridement. Follow-up periods ranged from 15 to 27 months. All flaps survived completely. All of the wounds except one healed completely. These flaps have adequate blood flow for the management of chronic bone infections. They also have many advantages, such as easy quick elevation, short operative time, and acceptable donor-site morbidity. Moreover, patients treated with neurocutaneous flaps do not require debulking procedures or special shoes. Reconstruction with neurocutaneous flaps after radical débridement is a versatile alternative to the use of local or distant muscle flaps and calcanectomy procedures for patients with osteomyelitis of the os calcis. 相似文献
102.
Short-term (2–30 min) cyclic stretch activates the Na pump in cultured aortic smooth muscle cells (ASMCs). This effect of
stretch involves the phosphotidylinositol 3-kinase (PI 3-kinase) participation. Presently, we investigated whether this stimulation
is the result of translocation of Na+,K+-ATPase from endosomes to the plasma membrane. ASMCs were stretched 20% for 5 min using the Flexercell Strain Unit. The plasma
membrane and endosome fractions were isolated and Western blotted to localize the Na+,K+-ATPase α-1-subunit protein. Membrane marker enzyme, 5′ nucleotidase activity, and the early and recycling endosome markers
Rab4 and Rab11 were used to verify the enrichment of these fractions. Stretch increased Na+,K+-ATPase α-1 expression in plasma membrane fractions and decreased it in endosomes. PI 3-kinase inhibitors LY294002 and wortmannin
blocked the stretch-induced translocation of the Na+,K+-ATPase α-1-subunit. Rab4 and Rab11 were enriched in the endosomal fraction, whereas 5′ nucleotidase activity was enriched
in the plasma membrane fraction. We conclude that stimulation of the Na pump activity by shortterm cyclic stretch is the result,
at least in part, of transport of the α-subunit of the enzyme from endosomes to the plasma membrane. 相似文献
103.
104.
Thomson M Mustafa T Ali M 《Prostaglandins, leukotrienes, and essential fatty acids》2000,63(4):217-221
We have shown previously that fresh garlic extract is effective in reducing thromboxane formation by platelets both in vivo and in vitro animal models of thrombosis. In the present study, the effect of different concentrations of a single dose of aqueous extracts of garlic and onion were evaluated on serum thromboxane-B(2)synthesis in rabbits. Different concentrations of garlic and onion were administered as single doses in the ear vein of rabbits. Rabbits were bled before and at different intervals after the infusion of garlic or onion extracts. Venous blood was collected and allowed to clot at 37 degrees C for 1 h. Thromboxane-B(2)level was measured in the serum by radioimmunoassay. It was observed that garlic inhibits the thrombin-induced platelet synthesis of TXB(2)in a dose-and time-dependent manner. Maximum inhibition of TXB(2)occurred between 0.5 h and 6 h at 25 and 100 mg kg(-1)garlic. At 24 h post-garlic infusion TXB(2)inhibition was reduced to 15% of the control and TXB(2)levels were comparable to that of the control values at 72 h pots-garlic infusion. Infusion of 100 mg kg(-1)onion extract did not elicit any inhibitory effect on TXB(2)synthesis in the serum of rabbit during the treatment period. The rapid recovery of platelet cyclooxygenase activity after infusion of a single dose of garlic suggests that garlic should be taken more frequently in order to achieve beneficial effects in the prevention of thrombosis. 相似文献
105.
Mannan components of C. albicans (5 mg/kg, i.p.) and S. cerevisiae (2.5 mg/kg, i.p.) cell walls produced pyrogenic responses which were completely inhibited by indomethacin (5 mg/kg, s.c.) pretreatment in rats. A non-selective NOS inhibitor, L-NAME (10 mg/kg, s.c.), also inhibited the pyrogenic effectiveness of C. albicans mannan, whereas it was ineffective on the fever induced by S. cerevisiae mannan. A selective elevation in the serum TNF-alpha levels was observed at the initial phase of the fever due to S. cerevisiae mannan, whereas there was no significant change on the serum levels of TNF-alpha, IL-1beta and IFN-gamma during the latent period or at the initial phase of the fever induced by C. albicans mannan. Injections of N-linked and/or O-linked oligomannosides of the either mannan did not cause any significant change in the body temperature and serum cytokine levels. These data suggest that the mannan components of C. albicans and S. cerevisiae cell walls produce a prostaglandin-dependent fever in rats. The initial signal for fever seems to be different for each mannan. Data also indicate that integrity of the mannans is necessary for the pyrogenic response. 相似文献
106.
107.
108.
109.
Ahmet Yesildağ Ahmet Özden H. Ramazan Yılmaz Efkan Uz Yetkin Ağackıran Mihrican Yesildağ Nigar Yılmaz Rana Sırmalı Hüseyin Vural Mustafa Nazıroğlu 《Cell biochemistry and function》2009,27(3):142-147
It has been suggested that reactive oxygen species (ROS) plays an important role in radio contrast media (RCM)‐induced ischemia reperfusion tissue injury although antioxidants may have protective effects on the injury. We investigated the effects of erdosteine as an antioxidant agent on RCM‐induced liver toxicity in rats by evaluation of lipid peroxidation (as TBARS), catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH) and glutathione peroxidase (GSH‐Px) values and histological evaluation. Twenty‐one rats were equally divided into three groups as follows: control, RCM, and RCM plus erdosteine. RCM was intraperitoneally administered for 1 day. Erdosteine was administered orally for 2 days after RCM administration. Liver samples were taken from the rats and they homogenized in a motor‐driven tissue homogenizer. TBARS levels were significantly (p < 0.005) higher in RCM group than in control although SOD activities significantly (p < 0.05) decreased in RCM group. TBARS levels were lower in RCM plus erdosteine group than in control although SOD activity and GSH level increased (p < 0.05) in liver as compared to RCM alone. Erdosteine showed also histopathological protection (p < 0.0001) against RCM induced hepatotoxicity. GSH‐Px and CAT activities were not statistically changed by the erdosteine. According to our results, it can be concluded that radiocontrast media can induce oxidative stress in liver as suggested by previous studies. Erdosteine seems to be protective agent on the radiocontrast media‐induced liver toxicity by inhibiting the production of ROS via the enzymatic antioxidant system. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
110.
Synthesis,Characterization, and Biological Activities of Pendant Arm‐Pyridyltetrazole Copper(II) Complexes: DNA Binding/Cleavage Activity and Cytotoxic Studies 下载免费PDF全文
Shaik Mustafa Bommuluri Umamaheswara Rao Manubolu Surya Surendrababu Kalidindi Krishnam Raju Gollapalli Nageswara Rao 《化学与生物多样性》2015,12(10):1516-1534
2‐(1H‐Tetrazol‐5‐yl)pyridine ( L ) has been reacted separately with Me2NCH2CH2Cl?HCl and ClCH2CH2OH to yield two regioisomers in each case, N,N‐dimethyl‐2‐[5‐(pyridin‐2‐yl)‐1H‐tetrazol‐1‐yl]ethanamine ( L1 )/N,N‐dimethyl‐2‐[5‐(pyridin‐2‐yl)‐2H‐tetrazol‐2‐yl]ethanamine ( L2 ) and 2‐[5‐(pyridin‐2‐yl)‐1H‐tetrazol‐1‐yl]ethanol ( L3 )/2‐[5‐(pyridin‐2‐yl)‐2H‐tetrazol‐2‐yl]ethanol ( L4 ), respectively. These ligands, L1 – L4 , have been coordinated with CuCl2?H2O in 1 : 1 composition to furnish the corresponding complexes 1 – 4 . EPR Spectra of Cu complexes 1 and 3 were characteristic of square planar geometry, with nuclear hyperfine spin 3/2. Single X‐ray crystallographic studies of 3 revealed that the Cu center has a square planar structure. DNA binding studies were carried out by UV/VIS absorption; viscosity and thermal denaturation studies revealed that each of these complexes are avid binders of calf thymus DNA. Investigation of nucleolytic cleavage activities of the complexes was carried out on double‐stranded pBR322 circular plasmid DNA by using a gel electrophoresis experiment under various conditions, where cleavage of DNA takes place by oxidative free‐radical mechanism (OH ? ). In vitro anticancer activities of the complexes against MCF‐7 (human breast adenocarcinoma) cells revealed that the complexes inhibit the growth of cancer cells. The IC50 values of the complexes showed that Cu complexes exhibit comparable cytotoxic activities compared to the standard drug cisplatin. 相似文献