全文获取类型
收费全文 | 11354篇 |
免费 | 688篇 |
国内免费 | 73篇 |
专业分类
耳鼻咽喉 | 163篇 |
儿科学 | 405篇 |
妇产科学 | 398篇 |
基础医学 | 1028篇 |
口腔科学 | 361篇 |
临床医学 | 965篇 |
内科学 | 2436篇 |
皮肤病学 | 193篇 |
神经病学 | 543篇 |
特种医学 | 396篇 |
外科学 | 2217篇 |
综合类 | 359篇 |
现状与发展 | 1篇 |
一般理论 | 12篇 |
预防医学 | 709篇 |
眼科学 | 259篇 |
药学 | 915篇 |
中国医学 | 75篇 |
肿瘤学 | 680篇 |
出版年
2023年 | 119篇 |
2022年 | 346篇 |
2021年 | 537篇 |
2020年 | 302篇 |
2019年 | 382篇 |
2018年 | 473篇 |
2017年 | 276篇 |
2016年 | 376篇 |
2015年 | 382篇 |
2014年 | 503篇 |
2013年 | 652篇 |
2012年 | 896篇 |
2011年 | 856篇 |
2010年 | 484篇 |
2009年 | 378篇 |
2008年 | 609篇 |
2007年 | 666篇 |
2006年 | 620篇 |
2005年 | 540篇 |
2004年 | 480篇 |
2003年 | 400篇 |
2002年 | 382篇 |
2001年 | 127篇 |
2000年 | 111篇 |
1999年 | 101篇 |
1998年 | 67篇 |
1997年 | 53篇 |
1996年 | 43篇 |
1995年 | 34篇 |
1994年 | 41篇 |
1993年 | 27篇 |
1992年 | 87篇 |
1991年 | 52篇 |
1990年 | 66篇 |
1989年 | 58篇 |
1988年 | 43篇 |
1987年 | 47篇 |
1986年 | 24篇 |
1985年 | 41篇 |
1984年 | 29篇 |
1983年 | 37篇 |
1982年 | 20篇 |
1980年 | 19篇 |
1979年 | 33篇 |
1978年 | 20篇 |
1977年 | 26篇 |
1976年 | 18篇 |
1974年 | 34篇 |
1973年 | 32篇 |
1972年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Mohamed Sabbahi Bruce Etnyre Ibrahim Al-Jawayed Joseph Jankovic 《Clinical neurophysiology》2003,114(2):288-294
OBJECTIVE: The purpose of this study was to examine neurophysiological characteristics of dystonia patients using electromyographic soleus H-reflex methods. METHODS: Thirty normal healthy individuals were compared to 27 patients with focal (cervical) or generalized dystonia. Three H-reflex assessment methods were included: the ratio of maximum H-reflex to direct muscle potential (H/M ratio); vibration inhibition (H(v)/H(c) ratio); and H-reflex recovery curves (HRRC). RESULTS: Average H/M ratios between groups were not statistically significant. The average H(v)/H(c) ratio for the generalized dystonia group was significantly greater than the focal dystonia and normal groups. Average values of the HRRC showed the generalized dystonia group had significantly greater disinhibition than the focal dystonia and control groups during the early inhibition phase. The HRRC for the focal dystonia group was greater than normal and more similar to the generalized dystonia group during the late phases of the recovery curve. The average value of the localized late facilitation phase for the focal dystonia group was significantly greater than the control group and less than the generalized dystonia group. No differences were observed between groups for the average localized late inhibition phase of the recovery curve. CONCLUSIONS: Soleus H-reflex measures identified neurophysiologic differences between generalized dystonia, cervical dystonia and normal conditions. SIGNIFICANCE: This methodology enables analysis of the underlying characteristics of dystonic pathologies using soleus H-reflex methods rather than upper extremity H-reflex techniques. 相似文献
12.
Amplification and restriction endonuclease digestion of a large fragment of genes coding for rRNA as a rapid method for discrimination of closely related pathogenic bacteria. 总被引:5,自引:4,他引:1 下载免费PDF全文
By use of primers specific to conserved regions of the rRNA gene cluster, a discrete amplicon of approximately 5 kb was amplified by PCR from all 21 bacterial genera investigated. Subsequent endonuclease digestion of the PCR product with HaeIII distinguished between the three species of the human pathogen Francisella spp. on the one hand and four clinically relevant genomic groups of Acinetobacter spp. on the other hand. The described technique has the potential as a rapid method for discriminating between closely related species that are of clinical importance. 相似文献
13.
14.
Mechanisms by which Candida albicans induces endothelial cell prostaglandin synthesis. 总被引:1,自引:5,他引:1 下载免费PDF全文
S G Filler B O Ibe A S Ibrahim M A Ghannoum J U Raj J E Edwards Jr 《Infection and immunity》1994,62(3):1064-1069
One strategy for improving resistance to opportunistic pathogens is to determine host cellular responses during the invasion process and upregulate those responses that are relevant to host defense mechanisms. Within this context, we have shown previously that invasion of endothelial cells by Candida albicans in vitro causes increased production of prostaglandins. As a prerequisite for modulating endothelial cell prostaglandin production, we now characterize the mechanisms through which this process occurs. Endothelial cell invasion by C. albicans appeared to stimulate the conversion of arachidonic acid into prostaglandins by upregulating the synthesis of endothelial cell cyclooxygenase and increasing the activity of the endothelial cell phospholipase. The enhanced activities of these two enzymes were independent of calphostin C-sensitive protein kinase C and resulted in the increased production and extracellular secretion of prostaglandin I2 (PGI2), PGF2 alpha, and PGE2. The secretion of these prostaglandins had no effect on the amount of endothelial cell injury induced by C. albicans. The role of the increased prostaglandin secretion by endothelial cells is likely related to modulation of the leukocyte response at the candida-leukocyte-endothelial cell interface. 相似文献
15.
Sawsan Ibrahim Kreydiyyeh Rana Al-Sadi 《Journal of interferon & cytokine research》2002,22(10):1041-1048
The effect of interleukin-1beta (IL-1beta) on urine flow rates and Na(+)/K(+)-ATPase activity and expression was studied in rat intestinal and renal epithelia. The cytokine produced a significant diuretic effect and increased urine flow rate by around 10-fold compared with the control. This effect was considered to be secondary to the well-documented natriuretic effect of the cytokine described in the literature. On the other hand, we have shown previously that IL-1beta inhibits glucose absorption from the jejunum. As sodium excretion and glucose absorption are both dependent on Na(+)/K(+)-ATPase activity, the effect of the cytokine on the renal and intestinal pump was investigated. IL-1beta inhibited, in a dose-dependent manner, the activity of Na(+)/K(+)-ATPase in villus and crypt jejunal cells and in medullary and cortical kidney cells. Western blot analysis revealed a decrease in the protein expression of the enzyme, which was confirmed by the radiolabeled ouabain binding assay. The results suggest that the diuretic and natriuretic effect of IL-1beta and its inhibitory effect on glucose absorption are all due to downregulation of the Na(+)/K(+) pump in the kidney and jejunum. 相似文献
16.
Observer variation in the histopathological classification of thymoma: correlation with prognosis. 下载免费PDF全文
AIMS--To assess the ability of three histopathologists, experienced in thoracic surgical reporting, consistently to classify thymomas as cortical, medullary, or mixed pattern tumours. METHODS--Three histopathologists classified 74 thymomas (none frank carcinomas) as of either cortical, medullary, or mixed pattern, on two separate occasions. Kappa statistics were used to assess inter- and intra-observer agreement. Tumour type was compared with surgical stage as a predictor of biological behaviour. RESULTS--Inter- and intra-observer agreement were only moderate (kappa 0.48 and 0.52, respectively). For only 26 of 74 tumours could a categorisation be consistently agreed on. Follow up information was obtained for 73 cases, with a mean follow up period of five years. The prognoses for those 26 of 74 cases appeared to be at variance from previously reported studies, and showed internal inconsistency, with the mixed pattern category showing a worse survival than the cortical category. For the group as a whole, however, stage at presentation was related to survival, with an overall five year survival of 78% (100% for stage I, 84% for stage II, 27% for stage III and 0% for stage IV). CONCLUSIONS--The classification of thymomas into cortical, medullary, or mixed pattern tumours is difficult to apply. Surgical stage remains a better guide to prognosis. 相似文献
17.
Dose-intensive therapy for extensive-stage small cell lung cancer and extrapulmonary small cell carcinoma: long-term outcome. 总被引:1,自引:0,他引:1
Anthony D Elias Arthur T Skarin Paul Richardson Joseph Ibrahim Mary McCauley Emil Frei 《Biology of blood and marrow transplantation》2002,8(6):326-333
Treatment for extensive-stage small cell lung cancer (ES SCLC) or extrapulmonary small cell carcinoma (EPSC) is typically palliative. We set out to determine progression-free survival (PFS) and overall long-term survival of ES SCLC and EPSC patients, physiologically aged < or = 60 years, responding to first-line chemotherapy followed by high-dose combination alkylating agents with hematologic stem cell support. Patients in first-line chemotherapy response underwent stem cell collection (marrow, peripheral blood progenitor cells, or both) followed by high-dose therapy with 1 of 2 regimens: CBP (cyclophosphamide, cisplatin, and carmustine) or ICE (ifosfamide, carboplatin, and etoposide) with or without etanidazole. Involved-field radiotherapy was given to selected patients with oligometastatic disease distributed in sites allowing for reasonable radiation ports, and prophylactic cranial radiotherapy was given upon recovery to patients in complete response (CR) or near-CR. A total of 36 patients were treated. Of 29 patients with ES SCLC, 6 (21%) had achieved CR, 18 near-CR, and 5 partial response prior to high-dose therapy. Of 7 patients with EPSC, 3 (43%) had achieved CR, 3 had achieved near-CR, and 1 had progression of disease prior to high-dose therapy. Thirteen ES SCLC patients received high-dose CBP. Of the remaining 23 patients with SCLC or EPSC, 17 were treated with ICE and 6 with ICE plus etanidazole, a hypoxic cell sensitizer. Treatment-related mortality was 11% (4 of 36 patients). For all patients, the median event-free survival (EFS) was 5 months. The 2- and 5-year survivals after intensification were 12% (95% confidence interval [CI], 5%-31%) and 9% (95% CI, 3%-27%), respectively. Of the 30 patients in or near CR prior to high-dose therapy, 5 remain continuously progression-free (2 ES SCLC, 3 EPSC) for a median of 55 months (range, 1-96 months) after high-dose therapy. By multivariate analysis, factors associated with more favorable EFS were the use of a more aggressive induction regimen (ICE), and the EPSC histology. These factors were also associated with more favorable overall survival. Other factors associated with more favorable overall survival were the use of short induction therapy (< or = 4 cycles) and younger age (<50 years). Except for high-dose ICE with etanidazole, the use of high-dose systemic therapy in ES SCLC and EPSC was associated with low treatment-related morbidity and mortality over the past 5 years. Late complications were infrequent, and most patients returned to full-time work and activity, barring disease recurrence. Nonetheless, few patients with ES SCLC have progression-free long-term survival. We conclude that high-dose therapy is not indicated as an approach for ES SCLC, except as part of an investigative trial. Conversely, 3 of the 7 patients with EPSC remain relapse-free (range, 1-96 months), warranting further phase II evaluation of this approach in this population. 相似文献
18.
Axon-oligodendrocyte relations of Rip-immunolabelled and dye-injected oligodendrocyte units are characterised in the adult rat anterior medullary velum (AMV). Each oligodendrocyte unit comprised the oligodendrocyte cell body, processes and the internodal myelin segments they support. Oligodendrocyte units corresponded to classically described type I/II or type III/IV unit phenotypes which respectively myelinated discrete populations of small and large diameter axons, delineated by a myelinated fire diameter of 2-4 microns (diameter of the axon plus its myelin sheath). Within units, mean fibre diameter was directly related to mean internodal length and inversely related to the number of myelin sheaths in the unit. The relationship between fibre diameter and internodal length was retained in units which myelinated axons of different diameters, indicating that axon diameter was an important determinant of the longitudinal dimensions of myelin sheaths. We also show that type III/IV units maintained a far greater volume of myelin than type I/II units. It was concluded that type I/II and III/IV oligodendrocytes represent two functionally and morphologically distinct phenotypes whose distribution densities were determined by the diameter and spatial dispersion of axons. 相似文献
19.
Khalid Ibrahim Bzeizi Richard Smith Ali Albenmousa Madhukar Dama Faisal Aba-Alkhail Rajiv Jalan Dieter Broering 《Transplantation proceedings》2021,53(1):148-158
BackgroundRisk of nephrotoxicity in liver transplant patients on calcineurin inhibitors (CnIs) is a concern. Several controlled trials reported benefit of everolimus (EVR) in minimizing this risk when combined with a reduced CnI dose.BackgroundTo systematically review the efficacy and safety of EVR, alone or with reduced CnI dose, as compared to CnI alone post-liver transplantation.MethodsWe searched MEDLINE, Scopus, and the Cochrane Library for randomized controlled trials comparing EVR- and CnI-based regimens post-liver transplantation. Assessment of studies and data extraction were undertaken independently.ResultsEight studies were selected, describing 769 patients. Cockcroft-Gault GFR was higher at one (P = .05), 3, and 5 years (P = .030) in patients on EVR compared to those receiving CnI therapy. The composite endpoint of efficacy failure was similar between the 2 arms after 1, 3, and 5 years of study. More patients discontinued EVR due to adverse effects in 1 year; however, no difference was noted after 3 or 5 years. A higher rates of proteinuria, peripheral edema, and incisional hernia occurred in patients on EVR.ConclusionsThe analysis confirms noninferiority of EVR and reduced CnI combination. Combination regimen resulted in better renal function compared to standard CnI therapy. 相似文献
20.
Ali Yildiz Ekrem Islamoglu Mustafa Yuksel Ibrahim Erol Kaan Karamik Tuncay Cakir Mutlu Ates Murat Savas 《Current Urology》2021,15(2):111
Background:To evaluate the changes in penile sensation by electrophysiological tests in patients who underwent radical prostatectomy (RP) and to demonstrate the role of dorsal penile nerve injury in postoperative erectile dysfunction.Materials and methods:Twenty-six volunteer patients who were eligible for RP were included in the study. Preoperative penile sensory electromyography and the International Index of Erectile Function-5 (IIEF-5) questionnaire were done for each patient. Erectile function assessment and electrophysiological evaluation of penile sensation were repeated at postoperative 3rd and 6th months.Results:Postoperative IIEF-5 scores and electromyography values were significantly lower than preoperative findings (p < 0.05). The IIEF-5 scores in the nerve sparing-RP (NS-RP) group were significantly higher than the non-nerve sparing-RP (NNS-RP) group in the postoperative period. Nerve conduction velocity values in the NS-RP group were also higher than the NNS-RP group at the postoperative 3rd and 6th months. However, these changes were not statistically significant (p > 0.05).Conclusions:Patients who underwent RP have decreased penile sensation due to cavernous nerve damage and a possible dorsal penile nerve injury. The decrease of penile sensation may be associated with postoperative erectile dysfunction. 相似文献