全文获取类型
收费全文 | 8089篇 |
免费 | 362篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 157篇 |
儿科学 | 143篇 |
妇产科学 | 313篇 |
基础医学 | 1626篇 |
口腔科学 | 182篇 |
临床医学 | 599篇 |
内科学 | 1427篇 |
皮肤病学 | 156篇 |
神经病学 | 613篇 |
特种医学 | 388篇 |
外国民族医学 | 1篇 |
外科学 | 1534篇 |
综合类 | 130篇 |
一般理论 | 2篇 |
预防医学 | 241篇 |
眼科学 | 206篇 |
药学 | 379篇 |
中国医学 | 9篇 |
肿瘤学 | 370篇 |
出版年
2022年 | 42篇 |
2021年 | 102篇 |
2020年 | 48篇 |
2019年 | 98篇 |
2018年 | 105篇 |
2017年 | 104篇 |
2016年 | 132篇 |
2015年 | 158篇 |
2014年 | 176篇 |
2013年 | 246篇 |
2012年 | 387篇 |
2011年 | 420篇 |
2010年 | 250篇 |
2009年 | 244篇 |
2008年 | 416篇 |
2007年 | 409篇 |
2006年 | 388篇 |
2005年 | 445篇 |
2004年 | 411篇 |
2003年 | 400篇 |
2002年 | 382篇 |
2001年 | 187篇 |
2000年 | 141篇 |
1999年 | 141篇 |
1998年 | 75篇 |
1997年 | 78篇 |
1996年 | 71篇 |
1995年 | 57篇 |
1994年 | 51篇 |
1992年 | 48篇 |
1991年 | 76篇 |
1990年 | 52篇 |
1989年 | 51篇 |
1988年 | 63篇 |
1987年 | 52篇 |
1986年 | 50篇 |
1985年 | 49篇 |
1984年 | 36篇 |
1982年 | 44篇 |
1979年 | 36篇 |
1977年 | 37篇 |
1976年 | 38篇 |
1975年 | 44篇 |
1974年 | 50篇 |
1973年 | 51篇 |
1939年 | 36篇 |
1937年 | 38篇 |
1936年 | 35篇 |
1931年 | 38篇 |
1926年 | 38篇 |
排序方式: 共有8476条查询结果,搜索用时 0 毫秒
81.
Functional deficits are important factors influencing treatment tolerability and prognosis in elderly cancer patients. Measurement and quantification of these deficits are essential for successful planning and sustaining therapy. Comprehensive geriatric assessment (CGA) offers a systematic approach to assess and classify individual deficits. Due to the broad range of patient capabilities, types of neoplasm and treatment strategies it is important to make a sensible choice of instruments to obtain relevant information. Performing CGA successfully in daily practice is efficient and feasible. 相似文献
82.
83.
84.
Friedrich Boettner MD Eric I. Altneu BA Brendan A. Williams AB Matthew Hepinstall MD Thomas P. Sculco MD 《HSS journal》2010,6(1):66-70
To avoid the potential risks of allogeneic transfusion during total hip arthroplasty (THA), the use of preoperative autologous blood donation (PABD) has been utilized. We performed a retrospective chart review of 283 patients undergoing THA that either donated 1 U of autologous blood (188 patients) or did not donate autologous blood before surgery (95 patients) in order to investigate the difference in postoperative transfusion rate (autologous and allogeneic), the incidence of allogeneic transfusion, and the difference in cost of each protocol. In addition, the study compared transfusion rates in patients with and without preoperative anemia (hemoglobin (Hb) ≤ 12.5 g/dL). At 0.75 transfusions per patient versus 0.22 transfusions per patient, the PABD patients had a significantly higher overall transfusion rate. PABD significantly reduced the need for allogeneic blood in anemic patients (Hb ≤ 12.5 g/dL) from 52.6% to 11.8%. PABD did not have the same affect in nonanemic patients (allogeneic transfusion rate 5.7% versus 4.0%). The study demonstrated that nonanemic patients undergoing THA do not benefit from PABD, but it is effective for anemic patients. 相似文献
85.
Manuel Kramer Eleftherios Vairaktaris Emeka Nkenke Karl Andreas Schlegel Friedrich Wilhelm Neukam Michael Lell 《Journal of oral and maxillofacial surgery》2008,66(2):302-307
PURPOSE: The aim of the study was to compare multislice computed tomography angiography (MSCTA) to digital subtraction angiography (DSA) for vascular mapping of the head and neck. PATIENTS AND METHODS: In 50 patients who were scheduled for microvascular reconstruction of the mandible with osteomyocutaneous flaps, MSCTA was carried out before surgery. DSA served as the method of reference. Selective common carotid angiograms were acquired in 2 projections for both sides of the neck. A 64-slice spiral computed tomography (CT) was carried out with a dual-phase protocol, using the arterial phase images for 3-dimensional CTA reconstruction. Volume rendering was used to visualize MSCTA data. RESULTS: No adverse reactions or complications occurred during or after the procedures. All CT angiograms were of diagnostic quality. No statistically significant differences between MSCTA and DSA were found for the detection of branches of the external carotid artery that are relevant host vessels for microsurgery neither in the group of 26 patients who had not had surgical treatment before (P = .687), nor in the group of 24 patients who were affected by either a tumor recurrence or an infected osteoradionecrosis (P = .508). CONCLUSION: MSCTA proved to be a reliable alternative to DSA in vascular mapping for planning of microvascular reconstruction of the mandible. 相似文献
86.
Determination of erythrocyte antioxidant capacity in haemodialysis patients using electron paramagnetic resonance. 总被引:2,自引:1,他引:2
A Klemm C Voigt M Friedrich R Fünfstück H Sperschneider E G J?ger G Stein 《Nephrology, dialysis, transplantation》2001,16(11):2166-2171
BACKGROUND: The increased oxidative stress of uraemia is caused both by an increased generation of oxygen-free radicals and a decrease of antioxidative forces. There are, however, conflicting data concerning disturbances of the radical-scavenging power of red blood cells (RBCs) in uraemic patients. METHODS: The antioxidant capacities of the RBCs of 10 haemodialysis (HD) patients and 10 controls were examined after treatment with 0.324 mM tert-butylhydroperoxide (t-BOOH) in phosphate-buffered saline at 37 degrees C using electron paramagnetic resonance (EPR) with 5,5-dimethylpyrroline-N-oxide (DMPO) as a spin trap and glutathione (GSH) regeneration as an indicator of hexose monophosphate shunt (HMPS) activity. EPR investigations were also done after pre-incubation with N-ethylmaleimide (NEM) to inhibit the GSH system. Furthermore, we determined the RBC redox state in 15 HD patients and 15 controls. RESULTS: There was no difference between HD patients and controls in the elimination of t-BOOH-generated free radicals in the RBCs. A more than 20-fold increase in radical concentration was observed after GSH trapping with NEM. In this case, we found a delayed decrease of the relative radical concentration in HD patients compared with controls with a significant difference after 7 min (2.2+/-0.26 vs 1.60+/-0.21; P=0.005) and after 10 min (1.82+/-0.41 vs 0.83+/-0.44; P=0.001). GSH regeneration via HMPS did not differ between the RBCs of HD patients (99.5+/-13.5 nmol/min x ml RBC) and those of the controls (94.2+/-16.9 nmol/min x ml RBC). There were no differences in the RBC concentrations of GSH, GSSG, NADP, NADPH, and in the GSH/GSSG and NADP/NADPH ratios between HD patients and controls. CONCLUSIONS: These data suggest a strong antioxidant potential in the GSH system of erythrocytes without any evidence of a disturbance in HD patients. The HMPS pathway also appears not to be impaired in the RBCs of HD patients. However, the slower radical elimination in the RBCs of HD patients after inhibition of GSH-depending radical scavengers as compared with controls indicates a defect in the antioxidant forces outside the GSH system, and could be one reason for the reduced lifespan of RBCs in HD patients. 相似文献
87.
Thomas Hernandez-Richter Martin K. Angele Thomas Helmberger Karl-Walter Jauch Lutz Lauterjung Friedrich W. Schildberg 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2001,386(4):261-266
OBJECTIVE: In 1962, the procedure of arterial thrombembolectomy with the Fogarty catheter was established. Numerous studies have been published studying thrombembolectomies of the lower extremities. Limited information, however, is available following thrombembolectomy of the upper extremity after arterial occlusion. The aim of the present study, therefore, was to determine long-term results (3-5 years after thrombembolectomy) following thrombembolectomy of the upper extremity with the Fogarty catheter in a large retrospective clinical study. DESIGN: In the present study, 251 patients were encountered. Over a period of 20 years, 283 thrombembolectomies with the Fogarty catheter were performed on the upper extremity at the surgical department of the University of Munich. MAIN OUTCOME MEASUREMENTS: The appearance of local and general complications in the postoperative phase, as well as long-term results, were evaluated. RESULTS: The results indicate that general complications - i.e., cardiac insufficiency, cerebral ischemia, etc. - occurred in 18 patients (7.2%). Local complications - i.e., wound infection, persistence of ischemia, or hematoma - were evident in 51 patients (20.3%). Re-occlusion following thrombembolectomy was found in 21 patients (8.8%). The affected extremity had to be amputated in five cases (2.0%), and 14 patients (5.6%) died during the postoperative phase. As a result of multimorbidity of the patients and average age at the time of surgery (73 years), 40% of the patients had died before the date of examination. Nonetheless, 111 patients of the 117 living patients showed no complaints or minor coldness and pain following heavy exercise. CONCLUSIONS: The results of the present study indicate that, in most cases, thrombembolectomy with the Fogarty catheter represents a successful surgical method for the acute treatment of arterial occlusion of the upper extremity. 相似文献
88.
Resveratrol neuroprotective effects during focal cerebral ischemia injury via nitric oxide mechanism in rats 总被引:7,自引:0,他引:7
Tsai SK Hung LM Fu YT Cheng H Nien MW Liu HY Zhang FB Huang SS 《Journal of vascular surgery》2007,46(2):346-353
BACKGROUND: Our prior study showed that resveratrol could suppress infarct volume and exert neuroprotective effect on rats subjected to focal cerebral ischemia (FCI) injury. Recently, it has been reported in some literature that resveratrol protects the spinal cord, kidney, and heart from ischemia-reperfusion injury through upregulation of nitric oxide (NO). Therefore, this study was designed to investigate the role of nitric oxide on the neuroprotective mechanisms of resveratrol on rats after FCI injury. METHODS: The FCI injury was induced by the middle cerebral artery (MCA) occlusion for 1 hour and then a 24-hour reperfusion followed in the anesthetized Long-Evans rats. Resveratrol was intravenously injected after 1 hour MCA occlusion. RESULTS: Treatment of resveratrol (0.1 and 1 microg/kg) decreased the lactate dehydrogenase (LDH) in plasma and malondialdehyde (MDA) in FCI injury brain tissue, whereas the level of NO in plasma was increased. In addition, resveratrol downregulated protein and mRNA expression of inducible nitric oxide synthase (iNOS), and upregulated protein and mRNA expression of endothelial nitric oxide synthase (eNOS), while the expression of protein and mRNA of neuronal nitric oxide synthase (nNOS) was unchanged. Pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME, the nonselective NOS inhibitor) or L-N(5)-(1-iminoethyl)-ornithine (L-NIO, the eNOS selective inhibitor) completely blocked the effect of resveratrol in decreasing infarction volumes. CONCLUSIONS: This study demonstrated the important role of NO in the neuroprotective effect of resveratrol in FCI injury. 相似文献
89.
Battellini R Rastan AJ Fabricius A Moscoso-Luduena M Lachmann N Mohr FW 《The Annals of thoracic surgery》2007,83(3):1206-1209
Re-sternotomy for aortic valve replacement (AVR) in patients with a patent internal mammary artery (IMA) graft may present a challenging surgical problem. Thus, strategies to prevent IMA graft injury include avoiding its dissection and leaving the graft open. However, when aortic cross clamping and cardioplegia are required, this approach may be associated with cardioplegia washout, suboptimal myocardial protection, and anterior myocardial wall injury. We herein describe an alternative technique for AVR on the beating heart in 4 patients with patent IMA grafts. The IMA was left unclamped and continuous retrograde coronary sinus perfusion (RCSP) was administered. Additional simultaneous antegrade venous bypass graft perfusion was established according to the extent of native coronary artery disease as well as patency and level of aortic proximal anastomoses. Using additional coronary ostia backflow control, the aortic valve was successfully replaced on the beating heart in all four cases without perivalvular leak. Postoperatively, low creatine kinase-MB fraction levels and preserved or improved ventricular function suggested very good myocardial protection. No myocardial infarction occurred in any patient. In our experience, aortic valve replacement on the beating heart using simultaneous antegrade-retrograde blood perfusion is a safe and effective method in this challenging subset of patients to prevent myocardial injury and to minimize the risk of patent IMA injury. 相似文献
90.