全文获取类型
收费全文 | 8410篇 |
免费 | 514篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 84篇 |
妇产科学 | 126篇 |
基础医学 | 1073篇 |
口腔科学 | 102篇 |
临床医学 | 854篇 |
内科学 | 1926篇 |
皮肤病学 | 242篇 |
神经病学 | 589篇 |
特种医学 | 677篇 |
外国民族医学 | 5篇 |
外科学 | 1564篇 |
综合类 | 38篇 |
一般理论 | 2篇 |
预防医学 | 410篇 |
眼科学 | 48篇 |
药学 | 385篇 |
中国医学 | 29篇 |
肿瘤学 | 789篇 |
出版年
2023年 | 50篇 |
2022年 | 80篇 |
2021年 | 173篇 |
2020年 | 124篇 |
2019年 | 161篇 |
2018年 | 205篇 |
2017年 | 164篇 |
2016年 | 216篇 |
2015年 | 215篇 |
2014年 | 276篇 |
2013年 | 382篇 |
2012年 | 549篇 |
2011年 | 620篇 |
2010年 | 380篇 |
2009年 | 370篇 |
2008年 | 562篇 |
2007年 | 580篇 |
2006年 | 605篇 |
2005年 | 605篇 |
2004年 | 508篇 |
2003年 | 518篇 |
2002年 | 455篇 |
2001年 | 120篇 |
2000年 | 91篇 |
1999年 | 95篇 |
1998年 | 118篇 |
1997年 | 102篇 |
1996年 | 65篇 |
1995年 | 52篇 |
1994年 | 36篇 |
1993年 | 25篇 |
1992年 | 31篇 |
1991年 | 26篇 |
1990年 | 24篇 |
1989年 | 34篇 |
1988年 | 28篇 |
1987年 | 32篇 |
1986年 | 33篇 |
1985年 | 22篇 |
1984年 | 23篇 |
1983年 | 15篇 |
1982年 | 11篇 |
1981年 | 21篇 |
1980年 | 16篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1977年 | 6篇 |
1976年 | 14篇 |
1975年 | 6篇 |
1974年 | 8篇 |
排序方式: 共有8970条查询结果,搜索用时 15 毫秒
51.
52.
F. De Geeter F. R. Franken F. F. Knapp Jr A. Bossuyt 《European journal of nuclear medicine and molecular imaging》1994,21(4):283-291
Contradictory data have been published on the relative behaviour of fatty acids and flow tracers during the subacute stage of myocardial infarction. Therefore, the present study was set up (1) to investigate the potential occurrence of mismatches between -methyl-iodophenyl pentadecanoic acid (BMIPP), a fatty acid analogue, and Sestamibi, and to describe their nature, and (2) to relate these mismatches to clinical characteristics such as whether or not thrombolysis or percutaneous transluminal coronary angioplasty (PTCA) had been performed. Twenty-six patients were studied within 2 weeks after myocardial infarction. Sestamibi and BMIPP single-photon emission tomography (SPET) were performed within 4 days of one another. Activity of both tracers was scored in 16 basal, 16 midventricular and 8 apical segments, using a four-point grading system: 3 = normal (65% of maximum activity), 2 = mildly decreased (45%–64%), 1 = moderately decreased (25%–44%), 0 = severely decreased (0%–24%). Coronary arteriography was obtained during the same hospital stay. Four hundred and seventy-seven segments out of 1040 studied were abnormal for at least one tracer: 197 with higher Sestamibi activity (group I), 226 with equal scores for Sestamibi and BMIPP (group II) and 54 with higher BMIPP activity (group III). Seventy-five percent of group I segments and 84% of group III segments were found in infarct-related artery territories. Group I segments were associated with acute thrombolysis and/or PTCA (P < 0.01), and with the absence of prior infarction in the territory of the infarct-related artery (P < 0.001). Group III segments were associated with the absence of thrombolysis or PTCA (P < 0.001), with occlusion of the infarct-related artery (P < 0.001), with previous infarction in the same territory (P < 0.001) and with a- or dyskinesia in this territory (P < 0.001). These data could support the interpretation that areas in which the uptake of BMIPP is more decreased than that of Sestamibi (group I) are due to delayed recovery of fatty acid metabolism after reperfusion, whereas those with higher BMIPP than Sestamibi activity (group III) are accounted for by the enhanced metabolism induced by passive systolic wall stretch. 相似文献
53.
Axel Stäbler M.D. Richard G. H. Baumeister M.D. Ulrike Szeimies Ulrich Fink M.D. Hermann Berger M.D. 《Skeletal radiology》1994,23(2):103-106
Post-traumatic ulnar carpal translocation is a rare, severe ligamentous injury to the wrist. Radiologic findings include widening of the radiocarpal joint space at the radial styloid process and ulnar displacement of the carpus. Less than 50% of the lunate articulates with the radius in the neutral position; the lunate is tilted dorsally with palmar subluxation due to a ruptured radioscapholunate (RSL) ligament. This malposition should be called rotatory palmar subluxation of the lunate (RPSL), by analogy to rotatory subluxation of the scaphoid (RSS). In contrast to dorsiflexed intercalated segment instability (DISI), in RPSL the RSL ligament is ruptured and, in the majority of cases, the scapholunate ligament remains intact. A prompt diagnosis should lead to successful treatment. 相似文献
54.
Birgit?BittorfEmail author Susanne?Merkel Klaus?E.?Matzel Axel?Wein Arno?Dimmler Werner?Hohenberger 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2004,389(3):178-183
Background Objective of the study was to investigate particular clinicopathological features of colorectal signet-ring cell carcinoma.Methods The data of 34 patients with primary colorectal signet-ring cell carcinoma were compared with those of 4,458 consecutive patients with primary non-signet-ring cell colorectal adenocarcinoma between 1978 and 1999. For outcome analysis patients, after curative resection of signet-ring cell cancer, were matched for age, gender, tumour site and stage with patients suffering from poorly differentiated non-signet-ring cell colorectal adenocarcinoma.Results Signet-ring cell carcinoma patients were significantly younger than patients with non-signet-ring cell colorectal adenocarcinoma (median age 60 years vs 64 years, P=0.033). The most common tumour sites were the rectum (47%) and the right hemicolon (29%). They presented with significantly more advanced tumour stages and a significantly higher frequency of distant metastases (44% vs 21%, P=0.002). The rate of curative resections was significantly lower (35% vs 79%, P<0.001). However, the prognosis after curative resection of signet-ring cell cancer was as poor as in poorly differentiated non-signet-ring cell colorectal adenocarcinoma of the same stage (5-year survival rate 46% vs 57%, p=0.935).Conclusions Colorectal signet-ring cell carcinoma is characterized by diagnosis in more advanced tumour stages resulting in lower rates of curative resection. Prognosis is as poor as in non-signet-ring cell colorectal cancer of low differentiation in the same stage. 相似文献
55.
Wirth MP Weissbach L Marx FJ Heckl W Jellinghaus W Riedmiller H Noack B Hinke A Froehner M 《European urology》2004,45(3):267-70; discussion 270
OBJECTIVE: To assess the efficacy and the tolerability of flutamide as adjuvant treatment after radical prostatectomy for locally advanced, lymph node-negative prostate cancer. METHODS: Men with locally advanced, lymph node-negative prostate cancer were randomized after radical prostatectomy to receive either flutamide 750mg daily or no adjuvant treatment. Recurrence-free and overall survival were the study end points. Recurrence was defined as a PSA value greater than 5ng/ml or two values greater than 2ng/ml more than three months apart with increasing tendency or three values greater than 1ng/ml more than three months apart with increasing tendency or any clinical recurrence. RESULTS: 309 patients (157 in the control arm and 152 in the flutamide arm) were eligible for efficacy analysis. The median follow-up was 6.1 years. Recurrence-free survival was better in the flutamide group ( P=0.0041), there was, however, no detectable difference in overall survival ( p=0.92 ). Moreover, there was a considerable toxicity reported in the flutamide group. CONCLUSION: Although having some effect on disease recurrence, adjuvant flutamide treatment does not improve median-term overall survival after radical prostatectomy for locally advanced, lymph node-negative prostate cancer. 相似文献
56.
Albers P Weissbach L Krege S Kliesch S Hartmann M Heidenreich A Walz P Kuczyk M Fimmers R;German Testicular Cancer Study Group 《The Journal of urology》2004,171(5):1835-1838
PURPOSE: We evaluated the prognostic parameters of necrotic residual tumors after chemotherapy of advanced germ cell tumors to improve on the current indications for surgery. MATERIALS AND METHODS: Between January 1996 and January 2000, in 8 centers of the German Testicular Cancer Study Group, preoperative parameters were assessed to predict necrosis in the residual tumors of 261 patients with retroperitoneal residual tumor resection after first (92%) and second line (8%) chemotherapy. RESULTS: Of 232 evaluable patients 39 had pure seminoma and 5 had viable cancer (1 with seminoma) in the residual tumor. Of the remaining 193 patients with nonseminoma 35% had necrosis, 34% teratoma and 31% had viable carcinoma in the residual tumor. After multivariate analysis and exclusion of patients with seminoma, the 3 parameters independently predictive of necrosis were alpha-fetoprotein before chemotherapy less than 20 ng/ml, and tumor volume before and after chemotherapy. A mathematical model to predict necrosis yielded a test accuracy of 75%, a sensitivity to predict necrosis of 52% and a specificity of 87%. CONCLUSIONS: Patients with pure seminoma should not undergo residual tumor resection because 97% of patients who received adequate chemotherapy were found to have no residual seminoma. In cases of nonseminoma alpha-fetoprotein values before chemotherapy less than 20 ng/ml and a high percentage of shrinkage during chemotherapy reliably predicted only 19% of cases of necrosis. Therefore, this model is clinically irrelevant and patients with minimal residual disease should undergo surgery. New methods are necessary to improve the preoperative selection of patients after chemotherapy. 相似文献
57.
Induced adiposity and adipocyte hypertrophy in mice lacking the AMP-activated protein kinase-alpha2 subunit 总被引:4,自引:0,他引:4
AMP-activated protein kinase (AMPK) is considered as a cellular energy sensor that regulates glucose and lipid metabolism by phosphorylating key regulatory enzymes. Despite the major role of adipose tissue in regulating energy partitioning in the organism, the role of AMPK in this tissue has not been addressed. In the present study, we subjected AMPKalpha2 knockout (KO) mice to a high-fat diet to examine the effect of AMPK on adipose tissue formation. Compared with the wild type, AMPKalpha2 KO mice exhibited increased body weight and fat mass. The increase in adipose tissue mass was due to the enlargement of the preexisting adipocytes with increased lipid accumulation. However, we did not observe any changes in adipocyte marker expression, such as peroxisome proliferator-activated receptor-gamma, CCAAT/enhancer-binding protein alpha (C/EBPalpha) and adipocyte fatty acid-binding protein (aFABP/aP2), or total cell number. Unlike impaired glucose homeostasis observed on normal diet feeding, when fed a high-fat diet AMPKalpha2 KO mice did not show differences in glucose tolerance and insulin sensitivity compared with wild-type mice. Our results suggest that the increase in lipid storage in adipose tissue in AMPKalpha2 KO mice may have protected these mice from further impairment of glucose homeostasis that normally accompanies high-fat feeding. Our study also demonstrates that lack of AMPKalpha2 subunit may be a factor contributing to the development of obesity. 相似文献
58.
Replacement of the aortic root for acute prosthetic valve endocarditis: prosthetic composite versus aortic allograft root replacement 总被引:2,自引:0,他引:2
Leyh RG Knobloch K Hagl C Ruhparwar A Fischer S Kofidis T Haverich A 《The Journal of thoracic and cardiovascular surgery》2004,127(5):1416-1420
OBJECTIVE: Aortic root replacement for prosthetic aortic valve endocarditis with accompanying destruction of the aortic root is a well-established surgical intervention. However, there is still no consensus whether prosthetic material or allogeneic material should be used. Here we report on our experience with prosthetic composite and aortic allograft root replacement in such patients during a 10-year interval. METHODS: From 1991 through 2001, 29 patients with prosthetic aortic valve endocarditis combined with aortic root destruction underwent reoperation at our institution. Sixteen patients received aortic root replacement with a cryopreserved aortic root allograft (group A) and 13 with a prosthetic composite graft (group B). The interval between the initial operation and reoperation was 29 months (range, 5-168 months) in group A and 55 months (range, 7-248 months) in group B. RESULTS: Hospital mortality was 18.5% (n = 5 patients, 3 in group A and 2 in group B). Median follow-up was 21 months (range, 1-48 months) for group A and 34 months (range, 1-152 months) for group B (P >.2). Survival at 1 and 5 years was 81% +/- 10% and 81% +/- 10% in group A and 85% +/- 10% and 85% +/- 10% in group B, respectively. No patient underwent reoperation for recurrent prosthetic aortic valve endocarditis. CONCLUSIONS: Our results indicate that excellent long-term results can be achieved regardless of the material used for aortic root replacement in patients with prosthetic aortic valve endocarditis. 相似文献
59.
The Vista system: a new bipolar resection device for endourological procedures: comparison with conventional resectoscope 总被引:1,自引:0,他引:1
OBJECTIVE: Conventional transurethral resection of the prostate (TURP) uses a monopolar electrocautery system in which the current passes from the active electrode through the patient's body towards the return plate and may cause distant negative effects. In this study a new developed resection device, the Vista system, using a bipolar electrocautery system and 0.9% sodium chloride solution for irrigation, was evaluated in an ex-vivo model. METHODS: The modified model of the isolated blood perfused kidney was used to determine cutting qualities, ablation rate, blood loss and coagulation depth of the bipolar resectoscope. After ablating the renal tissue of a perfused kidney in a surface area, blood loss was semiquantitatively determined. Afterwards samples were taken and processed for histological evaluation of the coagulation depth. We compared the new bipolar resection device against a conventional monopolar resectoscope. RESULTS: We found good cutting qualities of the bipolar resectoscope although it is more difficult to start a cut. The ablation rate is determined by the width of the electrode and is similar to the standard device (30 cm(2)/min). The bleeding is reduced with increasing output powers (26.13 +/- 6.15 g/min (level 5); 20.49 +/- 5,47 g/min (level 6); 13.16 +/- 5,47 g/min (level 7); 10.43 +/- 4.76 g/min (level 8) and lower compared to a conventional monopolar resectoscope (17.08 +/- 4.47 g/min). The coagulation depth increases with higher output powers but is reduced compared to the standard device (118 +/- 22 microm (level 5); 121 +/- 23 microm (level 6); 141 +/- 62 microm (level 7); 163 +/- 30 microm (level 8) versus 287 +/- 57 (monopolar resectoscope)). CONCLUSION: Our results with the bipolar resection device for TURP suggest that it may offer an alternative to conventional TURP. As active and the return electrode are placed on the resectoscope, high current densities are achieved locally and complications caused by distant negative effects of the current are theoretically reduced in vivo. Furthermore the risk of TUR syndrome is theoretically eliminated by using physiological sodium chloride solution for irrigation. To prove the clinical significance of our ex-vivo findings, clinical studies including large numbers of patients have to be performed. 相似文献
60.