全文获取类型
收费全文 | 917篇 |
免费 | 47篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 34篇 |
妇产科学 | 18篇 |
基础医学 | 125篇 |
口腔科学 | 10篇 |
临床医学 | 49篇 |
内科学 | 269篇 |
皮肤病学 | 14篇 |
神经病学 | 91篇 |
特种医学 | 13篇 |
外科学 | 65篇 |
综合类 | 2篇 |
预防医学 | 76篇 |
眼科学 | 5篇 |
药学 | 48篇 |
中国医学 | 1篇 |
肿瘤学 | 145篇 |
出版年
2024年 | 1篇 |
2023年 | 15篇 |
2022年 | 19篇 |
2021年 | 38篇 |
2020年 | 14篇 |
2019年 | 22篇 |
2018年 | 34篇 |
2017年 | 22篇 |
2016年 | 31篇 |
2015年 | 26篇 |
2014年 | 30篇 |
2013年 | 45篇 |
2012年 | 82篇 |
2011年 | 74篇 |
2010年 | 44篇 |
2009年 | 31篇 |
2008年 | 52篇 |
2007年 | 64篇 |
2006年 | 64篇 |
2005年 | 60篇 |
2004年 | 60篇 |
2003年 | 49篇 |
2002年 | 41篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1989年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1978年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有970条查询结果,搜索用时 15 毫秒
121.
122.
Tagliaferri F Zani G Iaccarino C Ferro S Ridolfi L Basaglia N Hutchinson P Servadei F 《Acta neurochirurgica》2012,154(5):919-926
Background
The aim of this article was to review the clinical practice of “bone flap decompression” in Regional Neurosurgical Units with no particular protocol in use. 相似文献123.
Ambrogio P Londero Maria Orsaria Nadia Parisi Alice Tassi Carla Pittini Lorenza Driul Laura Mariuzzi 《International journal of clinical and experimental pathology》2021,14(6):734
Objective: Accelerated placental maturation is regarded as a sign of vascular malperfusion and is often interpreted as a compensatory response by the placenta. In vitro embryo culture affects placental development. This study assessed placental maturation in spontaneous conceived and in vitro conceived pregnancies. Methods: Retrospective cohort study on a single center between 2014 and 2017. For this study, preterm placentas of singleton pregnancies between 24 and 36 weeks were considered. Routine placental examinations were retrospectively reviewed. Results: During the considered period, 423 placentas of singleton pregnancies were assessed. Three hundred ninety-six placentas were from spontaneous conception and 20 from in vitro fertilization and embryo transfer (IVF/ET). IVF/ET was significantly associated with accelerated villous maturation (AVM) and distal villous hypoplasia (DVH) (P<0.05). Conclusions: Placental AVM and DVH were significantly associated with in vitro fertilization in singleton pregnancies. This result supports the hypothesis that AVM is a compensatory response by the placenta to improve its transport capacity in specific settings such as in vitro fertilization. 相似文献
124.
125.
Aristotelis C. Papayannis MD Abdul‐Rahman R. Abdel‐Karim MD Arif Mahmood MD Bavana V. Rangan BDS MPH Lorenza B. Makke RCIS Subhash Banerjee MD FSCAI Emmanouil S. Brilakis MD PhD FSCAI 《Catheterization and cardiovascular interventions》2013,81(3):488-493
Background : Optical coherence tomography (OCT) and near‐infrared spectroscopy (NIRS) allow assessment of the anatomy (OCT) and composition (NIRS) of coronary lesions. We sought to examine the association between pre‐stenting lipid core plaque (LCP), as assessed by NIRS and post‐stenting thrombus formation, as assessed by OCT. Methods : We reviewed the angiograms of nine patients who underwent coronary stenting in association with NIRS and OCT imaging. A large LCP by NIRS was defined as at least three 2‐mm yellow blocks on the NIRS block chemogram with >200° angular extent. Intracoronary thrombus was defined as a mass of medium reflectivity protruding into the vessel lumen, discontinuous from the surface of the vessel wall. Results : Mean age was 67 ± 7 years, and all patients were men, presenting with stable angina (56%), unstable angina (11%), or acute myocardial infarction (33%). The mean vessel lipid core burden index (LCBI) was 120 ± 45, and the mean highest 6‐mm LCBI was 386 ± 190. Three patients had a large LCP and two of them (66%) developed intrastent thrombus after stent implantation compared to none of six patients without large LCPs (0%, P = 0.02). The thrombus resolved after intracoronary glycoprotein IIb/IIIa administration and balloon postdilation. Postprocedural myocardial infarction occurred in 33% versus 17% of patients with and without large LCP, respectively (P = 0.57). Conclusion : Stenting of large LCPs may be associated with intrastent thrombus formation, suggesting that more intensive anticoagulant and/or antiplatelet therapy may be beneficial in such lesions. © 2012 Wiley Periodicals, Inc. 相似文献
126.
127.
Hydrophilic and Amphiphilic Forms of Drosophila Choline Acetyltransferase are Encoded by a Single mRNA 总被引:1,自引:0,他引:1
Natalie Salem Jana Medilanski Nathalie Pellegrinelli Lorenza Eder-Colli 《The European journal of neuroscience》1994,6(5):737-745
We have previously shown that the enzyme choline- O -acetyltransferase (ChAT) exists in a hydrophilic and an amphiphilic form in Drosophila head. A complementary DNA clone of 4.2 kb containing the entire coding region of ChAT was isolated from a cDNA library of Drosophila heads. The cDNA was subcloned in an expression vector and injected into the nucleus of Xenopus oocytes. Injected oocytes expressed high levels of ChAT activity. This activity was inhibited by bromoacetylcholine, a specific inhibitor of the enzyme. In the present study the non-ionic detergent Triton X-114 was used to analyse whether the expression of hydrophilic and amphiphilic ChAT was or was not directed by a single cDNA. The two forms of ChAT were found to be synthesized in injected oocytes. Approximately 9% of the recombinant enzyme partitioned as amphiphilic activity. This value was similar to that found for native amphiphilic ChAT in Drosophila heads. Sedimentation in sucrose gradients of amphiphilic enzyme was found to be influenced by the type of detergent present in the gradient whereas this was not the case for hydrophilic ChAT. Hydrophilic and amphiphilic enzyme activities differed in some of their biochemical properties. Amphiphilic ChAT was less sensitive to inhibition by the product acetylcholine than was hydrophilic ChAT. Moreover, amphiphilic ChAT was found to be more resistant than hydrophilic ChAT to heat inactivation at 45°C. These properties were observed for the native as well as for recombinant ChAT. These results demonstrate that the hydrophilic and amphiphilic forms of ChAT are derived from one mRNA. 相似文献
128.
Enzo Porteri Damiano Rizzoni Alfonso Piccoli Maurizio Castellano Giorgio Bettoni Maria Lorenza Muiesan Giancarlo Pasini Daniele Guelfi Roberto Zulli Enrico Agabiti Rosei 《Blood pressure》1998,7(5):324-330
Objective: We have evaluated the effects of a new calcium channel blocker, manidipine, given at both high, hypotensive and low, non-hypotensive doses, on vascular morphology, response to endothelin-1 and ICAM-1 production in mesenteric small resistance arteries of spontaneously hypertensive rats (SHR). Methods: Ten SHR were treated with manidipine 3 mg/kg per day (high dose) and 10 with manidipine 0.3 mg/kg/ per day (low dose). The drug was administered by gavage from the 4th to 12th weeks of age. Eighteen Wistar-Kyoto (WKY) rats and 18 SHR were kept untreated as controls. Rats were killed at 13 weeks. Mesenteric small arteries were dissected and mounted on a micromyograph for determination of indexes of vascular structure (media thickness, wall thickness, media/lumen ratio). Results: Systolic blood pressure was significantly reduced by the high dose of the drug, while no effect was observed with low-dose manidipine. A reduction in the media/lumen ratio was observed only in SHR treated with high-dose manidipine. The response to endothelin-1 in untreated SHR was significantly lower in comparison with WKY; a significant reduction was observed in SHR treated with high-dose manidipine. ICAM-1 vascular concentrations were higher in untreated SHR than in WKY controls. Both high- and low-dose manidipine reduced ICAM-1 concentrations toward normalization. Conclusions: Manidipine at high, hypotensive, but not at low, non-hypotensive doses has been proven to reduce structural alterations in mesenteric small resistance arteries, and to normalize vascular responses to endothelin-1. In addition, manidipine, at both low and high doses, may reduce ICAM-1 vascular production, thus suggesting a possible anti-atherogenic effect. 相似文献
129.
Derosa G Cicero AF D'Angelo A Tinelli C Ciccarelli L Piccinni MN Pricolo F Salvadeo S Montagna L Gravina A Ferrari I Galli S Paniga S Fogari R 《Journal of cardiovascular pharmacology》2006,47(4):508-512
Inflammation has been hypothesized to play a role in the development of hypertension. The high-sensitivity C-reactive protein (hs-CRP) is a well-studied marker of systemic inflammation that has a predictive power with regard to the development of hypertension. This study was designed to test the hypothesis that hs-CRP plasma levels are altered in hypertension. Moreover, the study was to assess whether chronic antihypertensive treatment with doxazosin would normalize hs-CRP and nitrites/nitrates. We measured plasma levels of hs-CRP and nitrites/nitrates in 44 normotensive subjects and in 44 patients with hypertension before and after doxazosin therapy for 4 months. hs-CRP plasma levels were significantly higher (P < 0.007) in untreated hypertensive group compared to controls. Significant decrease was observed for hs-CRP (P < 0.05) in hypertensive patients after antihypertensive treatment. Nitrites/nitrates were significantly lower (P < 0.0001) in the untreated hypertensive group compared to controls. A significant increase was observed for nitrites/nitrates (P < 0.05) in hypertensive patients after antihypertensive treatment. These results suggest that doxazosin treatment exerts anti-inflammatory effects in addition to its antihypertensive properties in hypertensive patients. 相似文献
130.
Antagonism of sphingosine-1-phosphate receptors by FTY720 inhibits angiogenesis and tumor vascularization 总被引:12,自引:0,他引:12
LaMontagne K Littlewood-Evans A Schnell C O'Reilly T Wyder L Sanchez T Probst B Butler J Wood A Liau G Billy E Theuer A Hla T Wood J 《Cancer research》2006,66(1):221-231
FTY720, a potent immunomodulator, becomes phosphorylated in vivo (FTY-P) and interacts with sphingosine-1-phosphate (S1P) receptors. Recent studies showed that FTY-P affects vascular endothelial growth factor (VEGF)-induced vascular permeability, an important aspect of angiogenesis. We show here that FTY720 has antiangiogenic activity, potently abrogating VEGF- and S1P-induced angiogenesis in vivo in growth factor implant and corneal models. FTY720 administration tended to inhibit primary and significantly inhibited metastatic tumor growth in a mouse model of melanoma growth. In combination with a VEGFR tyrosine kinase inhibitor PTK787/ZK222584, FTY720 showed some additional benefit. FTY720 markedly inhibited tumor-associated angiogenesis, and this was accompanied by decreased tumor cell proliferation and increased apoptosis. In transfected HEK293 cells, FTY-P internalized S1P1 receptors, inhibited their recycling to the cell surface, and desensitized S1P receptor function. Both FTY720 and FTY-P apparently failed to impede VEGF-produced increases in mitogen-activated protein kinase activity in human umbilical vascular endothelial cells (HUVEC), and unlike its activity in causing S1PR internalization, FTY-P did not result in a decrease of surface VEGFR2 levels in HUVEC cells. Pretreatment with FTY720 or FTY-P prevented S1P-induced Ca2+ mobilization and migration in vascular endothelial cells. These data show that functional antagonism of vascular S1P receptors by FTY720 potently inhibits angiogenesis; therefore, this may provide a novel therapeutic approach for pathologic conditions with dysregulated angiogenesis. 相似文献