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   1352491篇
  免费   97240篇
  国内免费   3022篇
耳鼻咽喉   19945篇
儿科学   40586篇
妇产科学   39079篇
基础医学   189915篇
口腔科学   40178篇
临床医学   114258篇
内科学   266485篇
皮肤病学   30475篇
神经病学   108220篇
特种医学   54400篇
外国民族医学   435篇
外科学   210606篇
综合类   31214篇
现状与发展   6篇
一般理论   475篇
预防医学   93495篇
眼科学   32110篇
药学   101142篇
  2篇
中国医学   3013篇
肿瘤学   76714篇
  2018年   12132篇
  2015年   12239篇
  2014年   17229篇
  2013年   25997篇
  2012年   34149篇
  2011年   36149篇
  2010年   21468篇
  2009年   20912篇
  2008年   34727篇
  2007年   37905篇
  2006年   38357篇
  2005年   37186篇
  2004年   36117篇
  2003年   35074篇
  2002年   34561篇
  2001年   63872篇
  2000年   65552篇
  1999年   55657篇
  1998年   14863篇
  1997年   13682篇
  1996年   13114篇
  1995年   12374篇
  1994年   11586篇
  1992年   42922篇
  1991年   41437篇
  1990年   40691篇
  1989年   39665篇
  1988年   37089篇
  1987年   36536篇
  1986年   35034篇
  1985年   33245篇
  1984年   24952篇
  1983年   21179篇
  1982年   12803篇
  1981年   11721篇
  1980年   10900篇
  1979年   24025篇
  1978年   17154篇
  1977年   14922篇
  1976年   13451篇
  1975年   15364篇
  1974年   18161篇
  1973年   17649篇
  1972年   16867篇
  1971年   15766篇
  1970年   14965篇
  1969年   14368篇
  1968年   13474篇
  1967年   12028篇
  1966年   11275篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
996.
997.
AIM: The complication of nerve injury after greater saphenous vein stripping for varicosity is subjective, and a method for objective evaluation has never been established. The aim of this study was to evaluate postoperative sensory changes by quantitative assessment of current perception threshold (CPT), and to clarify the relation between CPT and symptoms. PATIENTS AND METHODS: Between January 2003 and August 2005, 27 limbs in 18 patients were enrolled. Quantitative sensory function was determined through CPT using a Neurometer (Neurotron, Inc., USA), with which saphenous nerve neural fiber selective minimum sensing values against three electrical stimuli (2000, 250, 5 Hz) were measured. CPT measurements were scheduled on the day before the operation, and 2-7 days, 1, 3, and 6 months after the operation. RESULTS: An increase in CPT value of more than 20% or decrease to below 50% compared to the preoperative value with at least two stimuli was defined as CPT abnormality. Subjective symptoms were observed in 13 limbs in the early postoperative period, and 10 limbs showed CPT abnormality. In 6 limbs with a CPT increase over 20% with all three stimuli, neurological symptoms continued for 6 months. CONCLUSIONS: CPT evaluation provides an objective indication of neurological symptoms in the lower limb following varicose vein surgery.  相似文献   
998.
Extubation difficulties after long-term endotracheal intubation in neonates and infants require immediate re-intubation with a somewhat thinner endotracheal tube, continuation of long-term intubation for another 7–14 days with antibiotic and antiphlogistic therapy including antireflux treatment as well as a subtile endoscopic examination. A tracheostomy is not indicated before several attempts of extubation have failed. An anterior cricoid split should be indicated with great care and in premature neonates only. In manifest cicatrical stenoses, subtile endoscopic diagnostics are an essential prerequisite for the choice of surgical method and time of surgery. In rather mild stenoses (grade II), laryngotracheal reconstruction (LTR) with anterior wall cartilage grafting is presently regarded as method of choice. For subglottic stenoses of higher degrees (grade III and IV), partial cricotracheal resection (PCTR) is felt to be the most successful procedure. For all scarred stenoses involving the glottic level, LTR with posterior and anterior wall cartilage grafting appears to be the only suitable treatment. LTR with anterior wall grafting only as well as the PCTR can be performed as a single stage procedure with postoperative long-term intubation on an intensive care unit for one or more days. LTR with posterior and anterior wall grafting requires long-term stenting for several weeks or months depending upon the individual condition. For long-term stenting, our so-called double-tube-technique using a modified Montgomery T silicon tube together with a perforated tracheal cannula has proved to be the safest and least irksome technique.  相似文献   
999.
Background Diagnosis of brainstem lesions in children based on magnetic resonance imaging alone is a challenging problem. Magnetic resonance spectroscopy (MRS) is a noninvasive technique for spatial characterization of biochemical markers in tissues and gives information regarding cell membrane proliferation, neuronal damage, and energy metabolism. Methods We measured the concentrations of biochemical markers in five children with brainstem lesions and evaluated their potential diagnostic significance. Images and spectra were acquired on a 1.5-T imager. The concentrations of N-acetylaspartate, tetramethylamines (e.g., choline), creatine, phosphocreatine, lactate, and lipids were measured within lesions located at the brainstem using Point-resolved spectroscopy sequences. Results Diagnosis based on localized proton spectroscopy included brainstem glioma, brainstem encephalitis, demyelination, dysmyelination secondary to neurofibromatosis type 1 (NF 1), and possible infection or radiation necrosis. In all but one patient, diagnosis was confirmed by biopsy or by clinical follow-up. Conclusions This small sample of patients suggests that MRS is important in the differential diagnosis between proliferative and nonproliferative lesions in patients without neurofibromatosis. Unfortunately, in cases of NF 1, MRS can have a rather misdiagnosis role.  相似文献   
1000.
The authors present a case of amyloid infiltration involving the trigeminal nerve that mimicked a malignant cavernous sinus tumor with perineural tumor infiltration. A 64-year-old man presented with trigeminal nerve numbness. Imaging revealed a plaque-like enhancing lesion along the right lateral cavernous sinus extending anteriorly into Meckel's cave and involving the proximal V2 and V3 branches of the trigeminal nerve. The patient underwent an extradural frontotemporal craniotomy with middle fossa exposure of the cavernous sinus to diagnose and treat the presumed malignant cavernous sinus tumor. A reddish mass involving the lateral dural wall of the cavernous sinus was resected. The gasserian ganglion, V2, and V3, the latter of which was biopsied, were enlarged. Permanent histopathological studies showed microscopic eosinophilic, amorphous material, which stained positive for Congo red, and an absence of neoplastic cells. The final diagnosis was amyloidoma. Thus, amyloidomas can involve the trigeminal nerve or ganglia and should be considered in the differential diagnosis of a cavernous sinus lesion mimicking a tumor. Patients may have symptomatic improvement of trigeminal neuropathy with resection of the amyloidoma outside the nerve capsule that is compressing the nerve, while resection of the lesion from within the capsule may result in permanent trigeminal nerve dysfunction.  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