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   5845篇
  免费   354篇
  国内免费   53篇
耳鼻咽喉   30篇
儿科学   179篇
妇产科学   122篇
基础医学   837篇
口腔科学   250篇
临床医学   458篇
内科学   1605篇
皮肤病学   132篇
神经病学   584篇
特种医学   144篇
外科学   483篇
综合类   8篇
一般理论   1篇
预防医学   301篇
眼科学   26篇
药学   376篇
中国医学   5篇
肿瘤学   711篇
  2024年   27篇
  2023年   60篇
  2022年   141篇
  2021年   187篇
  2020年   123篇
  2019年   136篇
  2018年   169篇
  2017年   114篇
  2016年   147篇
  2015年   171篇
  2014年   247篇
  2013年   304篇
  2012年   474篇
  2011年   440篇
  2010年   257篇
  2009年   226篇
  2008年   412篇
  2007年   405篇
  2006年   384篇
  2005年   386篇
  2004年   314篇
  2003年   304篇
  2002年   315篇
  2001年   47篇
  2000年   27篇
  1999年   26篇
  1998年   52篇
  1997年   53篇
  1996年   34篇
  1995年   40篇
  1994年   29篇
  1993年   14篇
  1992年   20篇
  1991年   17篇
  1990年   19篇
  1989年   9篇
  1988年   10篇
  1987年   4篇
  1986年   20篇
  1985年   8篇
  1984年   11篇
  1983年   10篇
  1982年   11篇
  1981年   10篇
  1980年   5篇
  1974年   3篇
  1972年   3篇
  1971年   3篇
  1969年   3篇
  1968年   3篇
排序方式: 共有6252条查询结果,搜索用时 15 毫秒
21.
At the European Institute of Oncology, Milan, Italy, we have focused our interest on the use of intraoperative radiation therapy (IORT) in limited-stage breast cancer that is conservatively treated. A new technique to perform IORT was applied in 185 patients from July 1, 1999, to October 31, 2001. As the surgeon plays a crucial role in this procedure in selecting the patients, performing the breast resection, preparing the gland as a target to receive IORT, delivering the radiation directly to the mammary gland via a dedicated applicator, and, finally, reconstructing the breast, each phase of the surgical technique has been completely standardized and is described herein. The use of IORT in the conservative treatment of breast cancer could allow the course of external fractionated-dose radiation therapy to be completely avoided; IORT dramatically reduces radiation exposure of the skin, lung, and subcutaneous tissues and avoids the irradiation of the contralateral breast, which contributes to a very low incidence of radiation-induced sequelae. In our experience, IORT for limited-stage breast carcinoma is easy to perform and only briefly prolongs the duration of the surgical procedure.  相似文献   
22.

Objective

Frey's syndrome is a frequent sequela of parotidectomy, causing facial sweating and flushing because of gustatory stimuli. Although botulinum toxin type A has become first-line therapy for Frey's syndrome, some patients become resistant. In this study, we investigated whether another serotype, botulinum toxin type B, might be an effective alternative.

Study Design

Case series with planned data collection.

Setting

Otolaryngology department in a university hospital.

Subjects and Methods

Seven patients aged 30 to 68 years, with severe Frey's syndrome, underwent the Minor test and had 80 U of botulinum toxin type B per cm2 (mean total dose, 2354 U) injected intracutaneously in the mapped area of gustatory sweating. All patients were followed up for 12 months.

Results

One month after treatment, six of the seven patients reported that gustatory sweating and flushing had resolved, and, in the remaining patient, these symptoms had decreased. The Minor test confirmed a significant improvement. The subjective benefits remained stable for six months in four patients and for nine months in the remaining three patients; 12 months after treatment, all patients still reported some improvement.

Conclusion

Botulinum toxin type B afforded symptomatic relief in a small sample of patients with Frey's syndrome and might be considered a potential alternative to botulinum toxin type A.  相似文献   
23.
Solid organ transplantation is the standard treatment to improve both the quality of life and survival in patients with various end-stage organ diseases. The primary barrier against successful transplantation is recipient alloimmunity and the need to be maintained on immunosuppressive therapies with associated side effects. Despite such treatments in renal transplantation, after death with a functioning graft, chronic allograft dysfunction (CAD) is the most common cause of late allograft loss. Recipient recognition of donor histocompatibility antigens, via direct, indirect, and semidirect pathways, is critically dependent on the antigen-presenting cell (APC) and elicits effector responses dominated by recipient T cells. In allograft rejection, the engagement of recipient and donor cells results in recruitment of T-helper (Th) cells of the Th1 and Th17 lineage to the graft. In cases in which the alloresponse is dominated by regulatory T cells (Tregs), rejection can be prevented and the allograft tolerated with minimum or no immunosuppression. Here, we review the pathways of allorecognition that underlie CAD and the T-cell effector phenotypes elicited as part of the alloresponse. Future therapies including depletion of donor-reactive lymphocytes, costimulation blockade, negative vaccination using dendritic cell subtypes, and Treg therapy are inferred from an understanding of these mechanisms of allograft rejection.  相似文献   
24.
PURPOSE: To study the effect of the antiepileptic drug levetiracetam (LEV) on the patterns of intrinsic optical signals (IOSs) generated by slices of the somatosensory cortex obtained from 3- and 6-month-old WAG/Rij and age-matched, nonepileptic control (NEC) rats. METHODS: WAG/Rij and NEC animals were anesthetized with enfluorane and decapitated. Brains were quickly removed, and neocortical slices were cut coronally with a vibratome, transferred to a submerged tissue chamber, and superfused with oxygenated artificial cerebrospinal fluid (aCSF). Slices were illuminated with a dark-field condensor and examined with a x2.5 objective; images were processed with a real time digital video image-enhancement system. Images were acquired before (background) and during electrical stimulation with a temporal resolution of 10 images/s and were displayed in pseudocolors. Extracellular stimuli (200 micros; <4 V) were delivered through bipolar stainless steel electrodes placed in the white matter. RESULTS: IOSs recorded in NEC slices bathed in control aCSF became less intense and of reduced size with age (p < 0.05); this trend was not seen in WAG/Rij slices. Age-dependent decreases in IOS intensity and area size were also seen in NEC slices superfused with aCSF containing the convulsant 4-aminopyridine (4-AP, 5 microM); in contrast, significant increases in both parameters occurred with age in 4-AP-treated WAG/Rij slices (p < 0.05). Under any of these conditions, the IOS intensity and area size slices were larger in WAG/Rij than in NEC slices. LEV (50-500 microM) application to WAG/Rij slices caused dose-dependent IOS reductions that were evident both in control and in 4-AP-containing aCSF and were more pronounced in 6-month-old tissue. CONCLUSIONS: These data demonstrate age-dependent IOS modifications in NEC and WAG/Rij rat slices and identify a clear pattern of hyperexcitability that occurs in 6-month-old WAG/Rij neocortical tissue, an age when absence seizures occur in all animals. The ability of LEV to reduce these patterns of network hyperexcitability supports the potential use of this new antiepileptic drug in primary generalized epileptic disorders.  相似文献   
25.
The gold standard procedure for the evaluation of vesicoureteral reflux (VUR) is the radiographic voiding cystourethrography (VCUG); direct radionuclide voiding cystography (DRVC) is an alternative method for detecting VUR. A new imaging procedure, voiding urosonography (VUS) with contrast medium, has recently been introduced. We have carried out a comparative study of these three techniques in 157 patients (aged 6 weeks–4.7 years). VUS showed the presence of VUR in 91 of 311 renal units; VCUG detected reflux in 64 of 233 renal units, and the DRVC in 23 of 78 renal units. VCUG and VUS were compared in 118 patients, and both procedures showed the same grade of reflux in 56 refluxing units (kappa value 0.92); in six cases the reflux grade was greater at VUS than at VCUG. Seven cases of reflux detected by VUS were not identified on VCUG. VCUG did not show a grade of VUR that was higher than in VUS in any patient. In the identification of 4°–5° grade reflux, the sensitivity of VUS reached 100%. VUS and DRVC were found to be equally effective in the detection of VUR (kappa value 0.85). In conclusion, we found that VUS is a useful method for the diagnosis and grading of patients with VUR.  相似文献   
26.
Aim: To study the immune-modulating and anti-oxidant effects of beta-glucan, papaya, lactoferrin, and vitamins C and E on sperm characteristics of patients with asthenoteratozoospermia associated with leucocytosis. Methods: Fifty-one patients referred to our Sterility Center for semen analysis were selected. Sperm parameters were assessed before and after patient's treatment with beta-glucan, lactoferrin, papaya, and vitamins C and E. DNA damage was assessed by the acridine orange test and sperm structural characteristics were evaluated by transmission electron microscopy. Results: After 90 days of treatment, an increase in the percentage of morphologically normal sperm (17.0 ± 5.2 vs. 29.8 ± 6.5) and total progressive motility (19.0± 7.8 vs. 34.8 ± 6.8) were detected. Structural sperm characteristics as well as chromatin integrity were also improved after treatment. In terms of leukocyte concentration in seminal fluid, a significant reduction was recorded (2.2 ± 0.9 vs. 0.9± 0.2). Conclusion: The treatment of an inflammatory process by the synergic action of immune modulators and anti-oxidants could protect sperm during maturation and migration, leading to improved sperm function. (Asian JAndrol 2008 Mar;. 10: 201-206)  相似文献   
27.
Parotid neoplasms represent 3% of all head and neck tumours, and most are benign. Malignant tumours account for 14-25% of cases. Surgery is the treatment of choice, with options ranging from simple enucleation to radical parotidectomy. Sixteen patients presented with a history of a painless parotid lump. Diagnosis was achieved by ultrasound scan and MRI. Fifteen superficial parotidectomies and 1 nerve-sparing total parotidectomy were carried out. At histology, 10 pleomorphic adenomas, 4 Warthin's tumours, 1 lymphoepithelial cyst and 1 sebaceous adenocarcinoma were detected. In the single case of carcinoma, the 6 peri-glandular lymph nodes included in the specimen were metastasis-free. In 3 patients (20%) a transient paresis of the facial nerve was noted. The capsule appeared breached in only 1 case of pleomorphic adenoma. Four patients (26%) were diagnosed as suffering from Frey's syndrome. A salivary fistula was recorded in 2 patients (13%). During follow-up ranging from 3 to 96 months no tumour recurrence was recorded. Superficial parotidectomy seems to be the best choice of treatment for benign parotid tumours, since it allows complete excision of the tumour with sparing of the facial nerve. A radical procedure is, however, needed if malignancy is confirmed at frozen section.  相似文献   
28.
29.
Hypofractionated radiotherapy (HF) in 15 or 16 daily fractions is well established as an alternative in early breast cancer after breast‐conserving surgery. Evidences for a whole‐breast treatment even shorter, in 5‐10 fractions, are still scarce. Women 50 years or older, with early breast tumor (pT1‐2pN0), after breast‐conserving surgery were eligible to enter in this phase II trial and received whole breast once‐weekly hypofractionated radiotherapy (wHF‐RT) to a total dose of 30 Gy, in 5 fractions of 6 Gy. During treatment and in post‐treatment follow‐up the toxicity was assessed and graduated according to the “Common Terminology Criteria for Adverse Events” (CTCAE), v3.0. Breast pictures for esthetic comparison were taken in 5 timepoints and 2 breast surgeons independently graduated the cosmetics changes. The trial was registered with ClinicalTrials.gov, number NCT01965483. From October 2013 to November 2015, 44 patients were enrolled in the trial and treated according to the protocol of wHF‐RT. The median age was 70.5 years (51‐88 years), and the median follow‐up was 22 months (9‐33 months). Skin erythema was the most common acute adverse event. At the end of radiation, 30 patients (68.2%) had any grade of radiation dermatitis. Concerning cosmetic appearance, there was no significant difference between pretreatment and 1 year assessments. The 2‐year overall survival and disease‐free survival were, respectively 96.8% and 97.7%. There was only one distant recurrence and no local or regional recurrence. Once‐weekly hypofractionated radiotherapy is a feasible and well tolerated alternative for early breast cancer adjuvant management with acceptable acute toxicity and esthetic outcomes.  相似文献   
30.
Abstract Amyotrophic lateral sclerosis (ALS) is the most common form of motor neuron disease. We describe the case of a patient with a rapidly progressive form of ALS characterized by both upper and lower motor neuron impairment, no early bulbar signs and severe pain in all four extremities. The patient had a heterozygous c.271G > A mutation in SOD1, leading to an amino acids substitution of asparagine to aspartate at position 90 of the protein chain (p.D90N). Our report confirms that ALS patients with D90 codon heterozygous mutations may be associated with rapid progression and a prominent pain syndrome.  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