收费全文 | 103813篇 |
免费 | 8045篇 |
国内免费 | 4753篇 |
耳鼻咽喉 | 323篇 |
儿科学 | 2643篇 |
妇产科学 | 664篇 |
基础医学 | 7424篇 |
口腔科学 | 715篇 |
临床医学 | 14162篇 |
内科学 | 10600篇 |
皮肤病学 | 447篇 |
神经病学 | 7896篇 |
特种医学 | 5474篇 |
外国民族医学 | 10篇 |
外科学 | 24093篇 |
综合类 | 18859篇 |
现状与发展 | 8篇 |
一般理论 | 1篇 |
预防医学 | 4865篇 |
眼科学 | 974篇 |
药学 | 10126篇 |
55篇 | |
中国医学 | 4826篇 |
肿瘤学 | 2446篇 |
2024年 | 197篇 |
2023年 | 1539篇 |
2022年 | 2257篇 |
2021年 | 4163篇 |
2020年 | 3865篇 |
2019年 | 3239篇 |
2018年 | 3242篇 |
2017年 | 3588篇 |
2016年 | 3901篇 |
2015年 | 3831篇 |
2014年 | 6738篇 |
2013年 | 8411篇 |
2012年 | 6150篇 |
2011年 | 6678篇 |
2010年 | 5677篇 |
2009年 | 5407篇 |
2008年 | 5402篇 |
2007年 | 5482篇 |
2006年 | 5151篇 |
2005年 | 4568篇 |
2004年 | 3751篇 |
2003年 | 3277篇 |
2002年 | 2775篇 |
2001年 | 2445篇 |
2000年 | 2023篇 |
1999年 | 1661篇 |
1998年 | 1417篇 |
1997年 | 1351篇 |
1996年 | 1170篇 |
1995年 | 1136篇 |
1994年 | 875篇 |
1993年 | 715篇 |
1992年 | 603篇 |
1991年 | 502篇 |
1990年 | 430篇 |
1989年 | 408篇 |
1988年 | 318篇 |
1987年 | 302篇 |
1986年 | 245篇 |
1985年 | 326篇 |
1984年 | 258篇 |
1983年 | 154篇 |
1982年 | 169篇 |
1981年 | 178篇 |
1980年 | 139篇 |
1979年 | 100篇 |
1978年 | 96篇 |
1977年 | 67篇 |
1976年 | 76篇 |
1975年 | 48篇 |
Objective
Hypertonic saline (HTS) has potent immune and vascular effects. We assessed recipient pretreatment with HTS on allograft function in a porcine model of heart transplantation and hypothesized that HTS infusion would limit endothelial and left ventricular (LV) dysfunction following transplantation.Methods
Heart transplants were performed after 6 hours of cold ischemic storage. Recipient pigs were randomized to treatment with or without HTS (7.5% NaCl) before cardiopulmonary bypass (CPB). Using a myograft apparatus, coronary artery endothelial-dependent (Edep) and -independent (Eind) relaxation was assessed. LV performance was determined using pressure-volume loop analysis. Pulmonary interleukin (IL)-2, IL-6, and tumor necrosis factor (TNF)-α expression was measured.Results
Weaning from CPB and LV performance after transplantation were improved in HTS-treated animals. Successful weaning from CPB was greater in the HTS-treated hearts (8 of 8 vs 2 of 8; P < .05). Mean LV functional recovery was improved in the HTS-treated animals, as assessed by preload recruitable stroke work (65 ± 10% vs 27 ± 10%; P < .001) and end-systolic elastance (55 ± 7% vs 37 ± 4%; P < .001). Treatment with HTS resulted in improved Edep (mean maximum elastance [Emax], 56 ± 5% vs 37 ± 7%; P < .001) and Eind (mean Emax%, 77 ± 6% vs 52 ± 4%; P < .001) vasorelaxation compared with control. Pulmonary expression of IL-2, IL-6, and TNF-α increased following transplantation, whereas HTS therapy attenuated IL production (P < .001). Transplantation increased plasma TNF-α levels and LV TNF-α expression, whereas HTS prevented this up-regulation (P < .001).Conclusions
Recipient HTS pretreatment preserves allograft vasomotor and LV function, and HTS therapy limits CPB-induced injury. HTS may be a novel recipient intervention to prevent graft dysfunction. 相似文献Background
Partial nephrectomy (PN) is generally favored for cT1 tumors over radical nephrectomy (RN) when technically feasible. However, it can be unclear whether the additional risks of PN are worth the magnitude of renal function benefit.Objective
To develop preoperative tools to predict long-term estimated glomerular filtration rate (eGFR) beyond 30 d following PN and RN, separately.Design, setting, and participants
In this retrospective cohort study, patients who underwent RN or PN for a single nonmetastatic renal tumor between 1997 and 2014 at our institution were identified. Exclusion criteria were venous tumor thrombus and preoperative eGFR <15 ml/min/1.73 m2.Intervention
RN and PN.Outcome measurements and statistical analysis
Hierarchical generalized linear mixed-effect models with backward selection of candidate preoperative features were used to predict long-term eGFR following RN and PN, separately. Predictive ability was summarized using marginal , which ranges from 0 to 1, with higher values indicating increased predictive ability.Results and limitations
The analysis included 1152 patients (13 206 eGFR observations) who underwent RN and 1920 patients (18 652 eGFR observations) who underwent PN, with mean preoperative eGFRs of 66 ml/min/1.73 m2 (standard deviation [SD] = 18) and 72 ml/min/1.73 m2 (SD = 20), respectively. The model to predict eGFR after RN included age, diabetes, preoperative eGFR, preoperative proteinuria, tumor size, time from surgery, and an interaction between time from surgery and age (marginal ). The model to predict eGFR after PN included age, presence of a solitary kidney, diabetes, hypertension, preoperative eGFR, preoperative proteinuria, surgical approach, time from surgery, and interaction terms between time from surgery and age, diabetes, preoperative eGFR, and preoperative proteinuria (marginal ). Limitations include the lack of data on renal tumor complexity and the single-center design; generalizability needs to be confirmed in external cohorts.Conclusions
We developed preoperative tools to predict renal function outcomes following RN and PN. Pending validation, these tools should be helpful for patient counseling and clinical decision-making.Patient summary
We developed models to predict kidney function outcomes after partial and radical nephrectomy based on preoperative features. This should help clinicians during patient counseling and decision-making in the management of kidney tumors. 相似文献Findings: A 30-year-old man with complete paraplegia used the HAL® for 1 month (10 sessions) using his remaining muscle activity, including hip flexor and upper limb activity. Electromyography was used to evaluate muscle activity of the gluteus maximus, tensor fascia lata, quadriceps femoris, and hamstring muscles in synchronization with the Vicon motion capture system. A HAL® session included a knee extension session with the hip flexor and voluntary gait with upper limb activity. After using the HAL® for one month, the patient’s manual muscle hip flexor scores improved from 1/5 to 2/5 for the right and from 2/5 to 3/5 for the left knee, and from 0/5 to 1/5 for the extension of both knees.
Conclusion/clinical relevance: Knee extension sessions with HAL®, and hip flexor and upper-limb-triggered HAL® ambulation seem a safe and feasible option in a patient with complete paraplegia due to spinal cord injury. 相似文献
Methods: A retrospective analysis was performed to identify patients with isolated PCL injuries that underwent reconstruction between 2001 and 2014. Patients with multi-ligamentous injury or another concomitant knee pathology were excluded. Medical records were reviewed for demographic, clinical and operative data. Patients were contacted for administration of a telephone-based questionnaire which included the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation form, Lysholm-Tegner scales, Marx activity scale (MAS), return to sport status, and patient satisfaction instruments.
Results: A total of 15 isolated PCL reconstructions in 14 patients with a mean age of 27.5 years (range 17–43) met the study inclusion criteria; mean follow up was 6.3 years (range 1.4–15.2). Pre-operatively, the primary complaint was knee instability in all patients; on physical examination, lack of a firm end point during posterior drawer testing was found in 93% (14/15) of the knees. In total, 12 of 15 knees underwent transtibial, single-bundle PCLR and three of 15 underwent tibial inlay, double bundle PCLR. Graft types included: quadriceps autograft (7/15), Achilles allograft (6/15), and hamstring autograft (2/15). There were no graft failures in our patient cohort. At most recent follow up the mean scores respectively on the IKDC form, Lysholm-Tegner scales and MAS were (standard deviation): 77.3 (16.5), 83.1 (17.9), 6.13 (2.6), and 7.1 (6.0). All fourteen patients were athletes prior to their injury and 79% (11/14) returned to sport and overall patient satisfaction was 9.2/10.
Conclusions: Isolated PCLR provides good outcomes at mean medium-term follow up with restoration of function, high rate of return to sport and overall patient satisfaction. 相似文献