首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   11043篇
  免费   519篇
  国内免费   91篇
耳鼻咽喉   105篇
儿科学   206篇
妇产科学   95篇
基础医学   1203篇
口腔科学   167篇
临床医学   592篇
内科学   3132篇
皮肤病学   223篇
神经病学   753篇
特种医学   371篇
外科学   2433篇
综合类   70篇
预防医学   238篇
眼科学   123篇
药学   530篇
中国医学   27篇
肿瘤学   1385篇
  2023年   91篇
  2022年   176篇
  2021年   301篇
  2020年   135篇
  2019年   208篇
  2018年   244篇
  2017年   221篇
  2016年   265篇
  2015年   288篇
  2014年   399篇
  2013年   440篇
  2012年   800篇
  2011年   830篇
  2010年   438篇
  2009年   410篇
  2008年   683篇
  2007年   743篇
  2006年   777篇
  2005年   733篇
  2004年   755篇
  2003年   711篇
  2002年   707篇
  2001年   110篇
  2000年   77篇
  1999年   139篇
  1998年   146篇
  1997年   113篇
  1996年   108篇
  1995年   82篇
  1994年   79篇
  1993年   88篇
  1992年   40篇
  1991年   42篇
  1990年   37篇
  1989年   33篇
  1988年   25篇
  1987年   24篇
  1986年   26篇
  1985年   13篇
  1984年   14篇
  1983年   9篇
  1982年   14篇
  1981年   13篇
  1980年   13篇
  1979年   9篇
  1978年   10篇
  1977年   8篇
  1976年   5篇
  1974年   3篇
  1972年   3篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
We explored the circaseptan variation in 28-day case-fatalities for patients with subarachnoid hemorrhage (SAH) across days of the week. Data were obtained from the Takashima Stroke Registry, which covers approximately 50 000 residents of central Japan. There were 169 first-ever SAH cases registered during the period 1988–2003 (68 in males, 101 in females). We divided the SAH cases into two groups according to the day on which the SAH occurred: “weekend” and “weekday”. The 28-day case-fatality rate and 95% confidence interval (CI) were calculated. Multiple logistic regression analysis was used to calculate the adjusted odds ratio (95% CI) for weekday fatalities by entering all relevant patient-level variables into the model. The 28-day case-fatality rate for SAH was higher on weekdays (51.7%) than on weekends (32.6%; odds ratio 2.19; 95% CI: 1.10–4.49). The differences in fatality rate persisted after adjustment for age, sex, severity, family history of stroke and patient history of hypertension, diabetes mellitus, dyslipidemia, drinking and smoking. We observed a circaseptan variation in fatalities from SAH, with higher fatality rates during weekdays in our study population.  相似文献   
992.
The purpose of this study was to determine whether femoral neck fracture after cemented resurfacing hip arthroplasty (RHA) arises from intraosseous vascularity around the femoral head-neck junction. We implanted a replica of the femoral head component into osteoarthritic femoral heads and compared the intraosseous vascularity network between the femoral heads with and without the RHA procedure using microangiography through a retinacular artery with micro–computed tomography. Our results showed no significant difference in the vascularity around the femoral head-neck junction between the groups with and without the RHA procedure. These results suggest that deterioration of the intraosseous vascular network around the head-neck junction after RHA was not severe enough to induce complete avascularity.  相似文献   
993.
The existence of inorganic polyphosphates [poly(P)] in human cells has been demonstrated. In osteoblasts, it is suggested that the concentration of cellular poly(P) is relatively high. In this study, we examined whether poly(P) accelerates the differentiation of human mesenchymal stem cells (hMSCs) from patients with osteoarthritis (OA) and rheumatoid arthritis (RA) into osteoblastic cells. Alkaline phosphatase (ALP) activity was induced by poly(P) in hMSCs from both OA and RA. In Alizarin Red S and osteocalcin EIA, there was a significant difference between the control and poly(P) group. In real-time PCR, there was a significant difference in ALP, collagen type 1A, osteocalcin, and bone sialoprotein between the control and poly(P) group. Our findings suggest that poly(P) have the potent role of differentiating hMSCs into osteoblastic cells at the early and later stages of osteoblastic differentiation.  相似文献   
994.
The number of reports describing osteoporotic vertebral fracture has increased as the number of elderly people has grown. Anterior decompression and fusion alone for the treatment of vertebral collapse is not easy for patients with comorbid medical problems and severe bone fragility. The purpose of the present study was to evaluate the efficacy of one-stage posterior instrumentation surgery for the treatment of osteoporotic vertebral collapse with neurological deficits. A consecutive series of 21 patients who sustained osteoporotic vertebral collapse with neurological deficits were managed with posterior decompression and short-segmental pedicle screw instrumentation augmented with ultra-high molecular weight polyethylene (UHMWP) cables with or without vertebroplasty using calcium phosphate cement. The mean follow-up was 42 months. All patients showed neurologic recovery. Segmental kyphotic angle at the instrumented level was significantly improved from an average preoperative kyphosis of 22.8–14.7 at a final follow-up. Spinal canal occupation was significantly reduced from an average before surgery of 40.4–19.1% at the final follow-up. Two patients experienced loosening of pedicle screws and three patients developed subsequent vertebral compression fractures within adjacent segments. However, these patients were effectively treated in a conservative fashion without any additional surgery. Our results indicated that one-stage posterior instrumentation surgery augmented with UHMWP cables could provide significant neurological improvement in the treatment of osteoporotic vertebral collapse.  相似文献   
995.
To determine the role of percutaneous vertebroplasty (PVP) in bone formation and the union of vertebral pseudarthrosis, we analyzed 14 patients with an average follow-up duration of 21 months. Evaluation methods included back pain (visual analog scale: VAS), wedge angle, dynamic mobility, radiographic remodeling including callus and spur formation, and union status. The Student's t test was used for statistical analysis and a probability of less than 0.05 was determined as a significant difference. Back pain improved in all 14 patients with a VAS score of 57.8 ± 23.5 mm (average ± standard deviation) preoperatively and 14.7 ± 16.4 mm at the final follow-up (P < 0.001). The wedge angle decreased from 21.6° ± 8.3° (average ± standard deviation) preoperatively to 13.2° ± 6.9° at the final follow-up (P < 0.001). Callus formation was seen in four patients. Bony spurs were seen in the affected vertebra in preoperative radiographs in all patients, and were further developed to a solidified form during follow up after PVP. Dynamic mobility of the affected vertebrae was 6.9 ± 2.9 mm preoperatively, which decreased to 1.1° ± 0.7° at the final follow-up (P < 0.001). Notably, all patients showed the dynamic vertebral mobility of 2 mm or less. Nevertheless, only two patients exhibited the dynamic vertebral mobility of 0 mm at the final follow-up, which is referred to as bone union. These findings indicate that PVP serves as a mechanical stabilizer for vertebral pseudarthrosis, which leads to immediate pain relief and segmental bony responses.  相似文献   
996.

Purpose

To evaluate the frequency and prognostic importance of neuroendocrine differentiation (NED) in Japanese breast cancer patients.

Methods

We used standard immunohistochemical techniques to examine 50 patients who underwent resection of breast cancer between 1988 and 1993 at the Department of Surgery II, Nagoya University Hospital, for NED, defined as positive reactivity for four markers: neuron-specific enolase (NSE), synaptophysin, CD57, and chromogranin A (CGA). Neuroendocrine differentiation was defined by the presence of at least one marker including CGA, CD57, and synaptophysin, or at least two markers when one was positive for NSE.

Results

Neuroendocrine differentiation was found in 13 (26%) of the 50 patients examined. There were no significant differences in the distribution of patients with positive or negative NED in terms of age, menopausal status, tumor size, lymph node metastasis, histological grade, ER, PgR, and HER2. We calculated the cumulative survival rates of patient groups according to NED status, and found no significant difference in overall or disease-free survival between patients with and those without NED.

Conclusion

Neuroendocrine differentiation was identified in a subset (26%) of Japanese breast cancer patients, but this appeared to have no relationship with established prognostic factors or patient outcome.  相似文献   
997.
998.
Higher complication rates and lower survivorship are still seen for total elbow arthroplasties compared to total knee and hip arthroplasties. This is partly due to polyethylene wear of the articular surface induced by excessive articular contact stress during elbow motion. The aim of this study was to dynamically evaluate in vivo three-dimensional elbow motion after total elbow arthroplasty. Twelve patients (15 elbows) who underwent operation with the Osaka University Model Total Elbow System were analysed using X-ray fluoroscopic imaging and a two-dimensional/three-dimensional registration technique, which could accurately estimate the three-dimensional spatial position of components. Valgus/varus angle and rotation between humeral and ulnar components showed wide variations among patients. Elbows with valgus angle and internal rotation >10° could induce edge-loading of the articular surface. Component alignment, articular configuration, and soft-tissue balance can affect the kinematics of total elbow arthroplasty.  相似文献   
999.
Aim: Several studies have reported that insulin resistance raises the risk of primary hepatocellular carcinoma (HCC). We conducted a prospective, case series study to test the impact of insulin resistance on the recurrence after curative radiofrequency ablation (RFA) of stage I HCC in HCV‐positive patients. Methods: From January 2006 to December 2007, 226 consecutive patients underwent treatment for primary HCC at our institutions, including 37 stage I cases. Among them, 33 were HCV‐positive, and three, six and 24 received curative surgery, transarterial chemoembolization or RFA, respectively. In the 24 patients treated with RFA, recurrence‐free survival was analyzed using the Kaplan–Meier method. The factors contributing to recurrence of HCC were subjected to univariate and multivariate analyses using the Cox proportional hazards model. Insulin resistance was estimated by the Homeostatic Model Assessment of Insulin Resistance (HOMA‐IR). Results: Kaplan–Meier analysis showed that the recurrence‐free survival was lower in patients with higher HOMA‐IR (>2.3, P = 0.0252) or with lower serum albumin level (<3.3 g/dL, P = 0.0004). In the univariate analysis, HOMA‐IR (P = 0.0420) and albumin (P = 0.0036) were significantly associated with recurrence of HCC. Multivariate analysis revealed albumin (odds ratio = 0.01, 95% confidence interval = 0.0002–0.015, P = 0.0001) and HOMA‐IR (odds ratio = 3.85, 95% confidence interval = 1.57–14.2, P = 0.0015) to be independent predictors for recurrence of HCC. Conclusion: Serum albumin level and HOMA‐IR were independent risk factors for recurrence of stage I HCC after curative RFA in HCV‐positive patients. Patients with these factors require closer surveillance.  相似文献   
1000.
A 60-year-old man who had been diagnosed as rheumatoid arthritis admitted to our hospital by dysesthesia on his legs with edema. Nerve conduction velocity test led to diagnosis of mononeuritis multiplex. Magnetic resonance imaging (MRI) of lower legs showed high intensity in slow tau inversion recovery. Typical vasculitis with neutrophil-dominant cell infiltration was observed by muscle biopsy without inflammatory myopathy or fascitis. Diagnosis was made by rheumatoid vasculitis found in crural muscles. Intravenous cyclophosphamide with oral tacrolimus effectively improved dysesthesia with reduction of inflammatory response.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号