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   1919篇
  免费   78篇
  国内免费   18篇
耳鼻咽喉   29篇
儿科学   80篇
妇产科学   51篇
基础医学   139篇
口腔科学   60篇
临床医学   180篇
内科学   360篇
皮肤病学   86篇
神经病学   235篇
特种医学   98篇
外科学   315篇
综合类   21篇
一般理论   1篇
预防医学   67篇
眼科学   99篇
药学   128篇
中国医学   5篇
肿瘤学   61篇
  2023年   16篇
  2022年   28篇
  2021年   55篇
  2020年   28篇
  2019年   46篇
  2018年   53篇
  2017年   46篇
  2016年   56篇
  2015年   85篇
  2014年   70篇
  2013年   120篇
  2012年   147篇
  2011年   137篇
  2010年   98篇
  2009年   96篇
  2008年   144篇
  2007年   182篇
  2006年   139篇
  2005年   113篇
  2004年   102篇
  2003年   93篇
  2002年   63篇
  2001年   18篇
  2000年   16篇
  1999年   11篇
  1998年   13篇
  1997年   5篇
  1996年   4篇
  1995年   4篇
  1994年   1篇
  1992年   2篇
  1991年   3篇
  1990年   3篇
  1987年   1篇
  1982年   2篇
  1976年   1篇
  1974年   2篇
  1973年   1篇
  1972年   6篇
  1971年   4篇
  1964年   1篇
排序方式: 共有2015条查询结果,搜索用时 15 毫秒
81.

Purpose

The aim of this study was to evaluate the effect of breast magnetic resonance imaging (MRI) on preoperative or intraoperative surgical planning.

Methods

One hundred and sixty females with breast cancer were enrolled in the study. The contribution of MRI compared to MMG and USG, their histopathological concordance, and their impact on surgical treatment were evaluated prospectively.

Results

In 48 (30.0%) of the patients, MRI identified suspicious lesions that were not detected by MMG and USG. The diagnosis by MRI was accurate in 17 (10.6%) of them, while in remaining 31 patients (19.4%) the additional lesions found by MRI and interpreted as malignant were found not to be malignant. The pathological accordance of MRI and MMG compared with USG were 69.3 and 70.0%, respectively, whereas individually, MMG and USG were in accordance with the pathological examination in 52.9 and 67.9% of the cases, respectively.

Conclusions

Assessment of the tumor size, multifocality, multicentricity, and presence of ductal carcinoma in situ by MRI may lead to misinterpretations in the majority of patients. The surgical approach should not be changed based solely on MRI findings. An accurately interpreted MMG combined with USG may be sufficient in most cases.  相似文献   
82.
Context: Recurrent priapism is characterized by repetitive episodes of erections which are unrelated to sexual interest or stimulation. It is extremely rare in patients with spinal cord injury (SCI). There are a number of conservative agents used in the treatment.Findings: We describe the case of a 20-year-old male with cervical-5 American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade A tetraplegia as a result of a diving accident 2 years ago. He declared that the recurrent penile erections occurred up to 15–20 times day and night every day and lasted up to 20 min each time unrelated to sexual interest or stimulation. He was prescribed baclofen 10 mg, twice daily. The frequency and duration of erections decreased to 3–5 times/day lasting for about 5 min each and the patient reported a high treatment satisfaction.Conclusion: The presentation of this case is to remind clinicians this rare but distressing condition of recurrent priapism seen in men with complete spinal cord lesions and to summarize the use of medications, most commonly baclofen, to alleviate the condition.  相似文献   
83.
Fibroblast growth factor‐23 (FGF23) is a bone‐derived hormone regulating vitamin D hormone production and renal handling of minerals by signaling through an FGF receptor/αKlotho (Klotho) receptor complex. Whether Klotho has FGF23‐independent effects on mineral homeostasis is a controversial issue. Here, we aimed to shed more light on this controversy by comparing male and female triple knockout mice with simultaneous deficiency in Fgf23 and Klotho and a nonfunctioning vitamin D receptor (VDR) (Fgf23/Klotho/VDR) with double (Fgf23/VDR, Klotho/VDR, and Fgf23/Klotho) and single Fgf23, Klotho, and VDR mutants. As expected, 4‐week‐old Fgf23, Klotho, and Fgf23/Klotho knockout mice were hypercalcemic and hyperphosphatemic, whereas VDR, Fgf23/VDR, and Klotho/VDR mice on rescue diet were normocalcemic and normophosphatemic. Serum levels of calcium, phosphate, and sodium did not differ between 4‐week‐old triple Fgf23/Klotho/VDR and double Fgf23/VDR or Klotho/VDR knockout mice. Notably, 3‐month‐old Fgf23/Klotho/VDR triple knockout mice were indistinguishable from double Fgf23/VDR and Klotho/VDR compound mutants in terms of serum calcium, serum phosphate, serum sodium, and serum PTH, as well as urinary calcium and sodium excretion. Protein expression analysis revealed increased membrane abundance of sodium‐phosphate co‐transporter 2a (NaPi‐2a), and decreased expression of sodium‐chloride co‐transporter (NCC) and transient receptor potential cation channel subfamily V member 5 (TRPV5) in Fgf23/Klotho/VDR, Fgf23/VDR, and Klotho/VDR mice, relative to wild‐type and VDR mice, but no differences between triple and double knockouts. Further, ex vivo treatment of live kidney slices isolated from wild‐type and Klotho/VDR mice with soluble Klotho did not induce changes in intracellular phosphate, calcium or sodium accumulation assessed by two‐photon microscopy. In conclusion, our data suggest that the main physiological function of Klotho for mineral homeostasis in vivo is its role as co‐receptor mediating Fgf23 action. © 2017 American Society for Bone and Mineral Research.  相似文献   
84.

Purpose

Humeral capitellum fractures comprise approximately 1% of all elbow fractures. In this study, we examined the clinical, radiographic, and functional outcomes following operative stabilization of Bryan and Morrey type IV fractures of the capitellum in adolescents. We applied headless cannulated screws in a posteroanterior direction without damaging the articular cartilage surface of the fractures.

Methods

Eight adolescent patients (six male, two female) with a mean age of 15 ± 2.1 years (range 13–18 years) were treated for type IV (McKee) humerus capitellum fractures. In the preoperative radiological evaluation, anteroposterior and lateral radiographs and computed tomography (CT) images were performed. A lateral surgical approach was used, and cannulated fully threaded headless screws were applied in a posteroanterior direction as fixation materials in the fracture reduction. The Mayo Elbow Performance Score was used in the evaluation of elbow joint functions.

Results

Patients were followed up for a mean of 24.6 months. Fracture union was achieved at a mean of 5 ± 0.92 weeks (range 4–6 weeks). The mean elbow extension flexion arc was 135° ± 13.47° (range 110°–150º) and the mean pronation supination arc was 156° ± 4.43° (150°–160°). In one patient, there was nonconformity in the humerus trochlea and in another patient, there was keloid formation on the surgical scar. All patients attained excellent results according to the Mayo Elbow Performance Score.

Conclusions

In the treatment of type IV capitellum fractures in adolescents, open reduction with a lateral surgical approach and fixation using posteroanterior directed, cannulated, fully threaded, headless screws is a reliable method to achieve a pain-free functional elbow joint.  相似文献   
85.
86.
Aims: To demonstrate the benefit of the combination amlodipine/valsartan 5/160 mg over amlodipine 10 mg, in producing a lower incidence of peripheral oedema for a comparable mean sitting systolic blood pressure (MSSBP) reduction. Methods: After a 4‐week amlodipine 5 mg run‐in phase, inadequately controlled hypertension patients (aged ≥ 55 years, MSSBP ≥ 130 and ≤ 160 mmHg) were randomised to receive amlodipine/valsartan 5/160 mg or amlodipine 10 mg for 8 weeks, followed by amlodipine/valsartan 5/160 mg for 4 weeks for all patients. Primary variables were MSSBP change from baseline to week 8 and incidence of peripheral oedema reported as an AE. Resolution of peripheral oedema was assessed 4 weeks after switching patients from amlodipine 10 mg to amlodipine/ valsartan 5/160 mg. Results: At week 8, MSSBP showed greater reduction with amlodipine/valsartan 5/160 mg than amlodipine 10 mg (least square mean: ?8.01 vs.?5.95 mmHg, p < 0.001 for non‐inferiority and p = 0.002 for superiority). Systolic control, overall BP control and systolic response rate at week 8 were significantly higher with combination than amlodipine 10 mg (34 vs. 26%; 57 vs. 50%; 36.57 vs. 27.77%, respectively). Incidence of peripheral oedema was significantly lower with the combination than amlodipine 10 mg (6.6 vs. 31.1%, p < 0.001). Peripheral oedema resolved in 56% patients who switched from amlodipine 10 mg to the combination, without the loss of effect on BP reduction. Conclusion: In non‐responders to amlodipine 5 mg, treatment with amlodipine/valsartan 5/160 mg induced significantly less peripheral oedema than amlodipine 10 mg for similar BP reduction. Peripheral oedema resolved in > 50% patients switching from amlodipine 10 mg to the combination.  相似文献   
87.
88.
Organophosphorus insecticides may induce oxidative stress leading to generation of free radicals and alteration in antioxidant system. The aim of this study was to examine the potency of trichlorfon, an organophosphate insecticide, to induce oxidative stress response in human erythrocytes in vitro. For this purpose trichlorfon solutions in different concentrations and erythrocyte solutions were incubated at 37 °C for 60 min. At the end of the incubation time, malondialdehyde (MDA), an end product of lipid peroxidation, total glutathione, reduced glutathione (GSH) levels, activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) enzymes were determined by spectrophotometric methods. Trichlorfon increased MDA formation depended on the concentration. On the other hand, decreases in the GSH-Px activity, GSH levels and increases in the total glutathione levels, SOD and CAT activities were seen in the studied concentrations. The present findings indicate that the in vitro toxicity of trichlorfon may be associated with oxidative stress.  相似文献   
89.
Neuroprotective effects of propofol following global cerebral ischemia in rats   总被引:15,自引:0,他引:15  
Propofol has cerebral vascular and metabolic effects similar to those of barbiturates, and it is used to maintain neurosurgical anesthesia because it reduces cerebral metabolic rate, cerebral blood flow, and intracranial pressure. Although the use of propofol as a cerebral protectant during certain neurosurgical procedures has been advocated, consensus has not been reached as to a protective effect of propofol on cerebral ischemia. In this study we observed the neuroprotective effects of propofol during global cerebral ischemia-reperfusion injury by the use of four-vessel occlusion method in a rat model. We measured the levels of malondialdehyde as a marker of lipid peroxidation in ischemic tissue, and the results indicate that propofol plays a role in the inhibition of neuronal death induced by brain ischemia. Electronic Publication  相似文献   
90.
The authors describe a study in which groin flaps from 20 Wistar rats were transplanted to another group of 20 Wistar rats and, after various time intervals, the groin flaps were re-transplanted back to the original animals. The goal of the first transfers was to preserve the flap in the second group of animals (isopreservation). During the isopreservation period, the second rat (the preserver) was treated with steroids or FK506 for immunosuppression. Thirty-three free groin flap transfers were performed between 40 rats. If possible, the same flap was transferred twice between two animals, one as an isograft, and other as an autograft following an isopreservation period in 13 pairs of animals. (A second transfer was not possible in seven pairs of animals.) The period for isopreservation varied between 2 days and 1 week. The survival of the flap was observed by visual inspection, laser Doppler flowmeter measurements, and was correlated with serial histopathologic examinations of skin and vessel biopsy specimens, including the anastomosis site. The severity of histopathologic signs that might be related to developing rejection was increased by the preservation time, and was more noticeable after the second transfer. The authors showed that successful secondary transplantation of the rat groin flap with a 1-week follow-up could be achieved, following isopreservation of at least up to 5 days.  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