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   5561篇
  免费   372篇
  国内免费   8篇
耳鼻咽喉   68篇
儿科学   299篇
妇产科学   100篇
基础医学   705篇
口腔科学   182篇
临床医学   581篇
内科学   1236篇
皮肤病学   86篇
神经病学   476篇
特种医学   507篇
外科学   546篇
综合类   91篇
一般理论   10篇
预防医学   384篇
眼科学   95篇
药学   263篇
  1篇
中国医学   1篇
肿瘤学   310篇
  2021年   45篇
  2019年   36篇
  2018年   59篇
  2017年   48篇
  2016年   75篇
  2015年   64篇
  2014年   112篇
  2013年   163篇
  2012年   206篇
  2011年   231篇
  2010年   124篇
  2009年   104篇
  2008年   177篇
  2007年   223篇
  2006年   238篇
  2005年   199篇
  2004年   218篇
  2003年   210篇
  2002年   188篇
  2001年   165篇
  2000年   201篇
  1999年   145篇
  1998年   72篇
  1997年   65篇
  1996年   72篇
  1995年   91篇
  1994年   61篇
  1993年   62篇
  1992年   166篇
  1991年   155篇
  1990年   169篇
  1989年   165篇
  1988年   152篇
  1987年   135篇
  1986年   140篇
  1985年   135篇
  1984年   98篇
  1983年   86篇
  1982年   49篇
  1981年   47篇
  1980年   38篇
  1979年   80篇
  1978年   60篇
  1976年   47篇
  1975年   40篇
  1974年   44篇
  1973年   57篇
  1972年   51篇
  1971年   41篇
  1970年   40篇
排序方式: 共有5941条查询结果,搜索用时 15 毫秒
31.
The present study documents the characteristics of innervation of the rhinarium or hairless rat snout skin by light and electron microscopy. The outer glabrous surface is covered with a stratified squamous epithelium that forms both rete pegs and rete ridges, the latter on the inferior border near the philtrum. The glabrous skin contains numerous presumptive epidermal and dermal free nerve endings (FNE's), Merkel terminals at the base of the rete ridges and pegs, and simple, nonencapsulated corpuscles. A second region of dense innervation, found on an elevation of the inner wall of the vestibule, contains similar components of innervation, with the exception that no Merkel terminals were identified. Since no Merkel terminals were present in this area of the vestibule, intraepidermal as well as dermal FNE's could be identified with certainty. This skin is covered by a thin squamous epithelium overlying dense connective tissue. The simple corpuscles are similar to those in the rhinarium, as well as resembling those described in other species. FNE's were frequently observed intimately associated with simple corpuscles. Several examples of large FNE's with two to three layers of cytoplasmic lamellae were found, suggestive of transitional forms between FNE's and simple corpuscles. Thus, the pattern of sensory innervation in the glabrous rat snout skin is similar to that found in other furred species described to date, but in addition, the sensory innervation of ridged skin in the rat also resembles that of epidermis organized into rete pegs. This dense sensory innervation may be correlated with whisking behavior of the predominantly nocturnal rat.  相似文献   
32.
The fine-needle aspiration (FNA) cytology of two cases of granulocytic sarcoma involving the breast is reported along with the FNA cytology of one case of myeloid metaplasia (extramedullary hematopoiesis) involving an axillary lymph node. Two patients had known myeloproliferative disorders, while granulocytic sarcoma of the breast was the initial presentation of an unsuspected acute granulocytic leukemia in the other patient. Diff-Quik-stained preparations aided in the diagnosis of all three cases. Immunoperoxidase stains for factor VIII-related antigen helped confirm the megakaryocytic differentiation of the cells in the FNA cytology of myeloid metaplasia. Electron microscopic (EM) examination performed on the aspirated material also showed megakaryocytic differentiation of the bizarre cells. FNA cytology can make a specific diagnosis of granulocytic sarcoma and myeloid metaplasia. The workup of these unusual extramedullary myeloproliferative masses was aided when immunocytochemistry and EM were performed on the aspirated material.  相似文献   
33.
Characteristics of very poor outcome schizophrenia   总被引:2,自引:0,他引:2  
The authors compared 21 "Kraepelinian" schizophrenic patients who had been ill and dependent on others for the past 5 years with 76 chronic schizophrenic patients in remission or with exacerbations requiring hospitalization. The Kraepelinian patients met the criteria for schizophrenia by more diagnostic systems than the exacerbated patients, were less responsive to haloperidol, had more severe negative symptoms, and had similarly severe positive symptoms. They had cerebral ventricles that were more asymmetrical and a greater family history of schizophrenia spectrum disorders than the other chronic patients. These data suggest that patients with 5 years of illness and complete dependency on others may represent a subgroup of schizophrenia.  相似文献   
34.
Annals of Surgical Oncology - The aim of this study was to report outcomes following percutaneous microwave and cryoablation of lung metastases from adenoid cystic carcinoma (ACC) of the head and...  相似文献   
35.
There has been clinical speculation that parents of young stuttering children have expectations of their children's communication abilities that are not well-matched to the children's actual skills. We appraised the language abilities of 15 children close to the onset of stuttering symptoms and 15 age-, sex-, and SES-matched fluent children using an array of standardized tests and spontaneous language sample measures. Parents concurrently completed two parent-report measures of the children's communicative development. Results indicated generally depressed performance on all child speech and language measures by the children who stutter. Parent report was closely attuned to child performance for the stuttering children; parents of nonstuttering children were less accurate in their predictions of children's communicative performance. Implications for clinical advisement to parents of stuttering children are discussed.  相似文献   
36.
Localized scleroderma is distinct from the diffuse form of scleroderma and does not show Raynaud's phenomenon and visceral involvement. The imaging features in 23 patients ranging from 2 to 17 years of age (mean 11.1 years) were reviewed. Leg length discrepancy and muscle atrophy were the most common findings (five patients), with two patients also showing modelling deformity of the fibula. One patient with lower extremity involvement showed abnormal bone marrow signals on MR. Disabling joint contracture requiring orthopedic intervention was noted in one patient. In two patients with en coup de sabre facial deformity, CT and MR scans revealed intracranial calcifications and white matter abnormality in the ipsilateral frontal lobes, with one also showing migrational abnormality. In a third patient, CT revealed white matter abnormality in the ipsilateral parietal lobe. In one patient with progressive facial hemiatrophy, CT and MR scans showed the underlying hypoplastic left maxillary antrum and cheek. Imaging studies of areas of clinical concern revealed positive findings in half our patients.  相似文献   
37.
38.
A 71-year-old male presented with a large pituitary adenoma with superior extension into the optic chiasm and suprasellar cistern. He was treated with stereotactic radiosurgery to a dose of 16 Gy. Approximately 1 h after radiosurgery he developed fever; his temperature peaked at 105.1 degrees F and normalized about 20 h later. This case demonstrates that acute hyperthermia is a potential complication following high dose stereotactic radiosurgery for large pituitary tumours.  相似文献   
39.
OBJECTIVES: To determine if compression of the vitreous by an intraocular gas bubble diminishes the concentration of hyaluronic acid (NaHA). MATERIALS AND METHODS: Eighteen albino rabbits had air, xenon or perfluoroethane (C2F6) injected into the vitreous to displace 12.5% to 90% of the vitreous volume. After the gas was absorbed, the vitreous was analyzed for NaHA by the Carbazole method (1, 13). RESULTS: A 90% displacement diminished the NaHA concentration by 18.6%. Lesser displacements caused a lesser loss, but the differences are not significant. CONCLUSION: Intraocular gas injections, both large and small, reduce the concentration of NaHA and destabilize the vitreous structure.  相似文献   
40.
The high incidence of cancer in the rapidly expanding geriatric population presents a major challenge to the health care field. Since most cancers present and behave similarly in both older and younger persons, similar approaches to management must be considered in both. The elderly, however, are a heterogeneous group with individuals demonstrating varying degrees of comorbidity and physiologic change. Decisions, therefore, should be based on a sound knowledge of geriatric assessment and the factors important for "successful" aging rather than on chronological age alone.  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