全文获取类型
收费全文 | 23482篇 |
免费 | 1519篇 |
国内免费 | 112篇 |
专业分类
耳鼻咽喉 | 228篇 |
儿科学 | 630篇 |
妇产科学 | 494篇 |
基础医学 | 2727篇 |
口腔科学 | 500篇 |
临床医学 | 1912篇 |
内科学 | 5121篇 |
皮肤病学 | 354篇 |
神经病学 | 1249篇 |
特种医学 | 628篇 |
外国民族医学 | 4篇 |
外科学 | 3970篇 |
综合类 | 802篇 |
一般理论 | 19篇 |
预防医学 | 1828篇 |
眼科学 | 613篇 |
药学 | 2283篇 |
中国医学 | 269篇 |
肿瘤学 | 1482篇 |
出版年
2023年 | 249篇 |
2022年 | 680篇 |
2021年 | 942篇 |
2020年 | 568篇 |
2019年 | 705篇 |
2018年 | 819篇 |
2017年 | 585篇 |
2016年 | 543篇 |
2015年 | 698篇 |
2014年 | 929篇 |
2013年 | 1148篇 |
2012年 | 1708篇 |
2011年 | 1693篇 |
2010年 | 961篇 |
2009年 | 744篇 |
2008年 | 1281篇 |
2007年 | 1200篇 |
2006年 | 1156篇 |
2005年 | 1065篇 |
2004年 | 951篇 |
2003年 | 835篇 |
2002年 | 729篇 |
2001年 | 568篇 |
2000年 | 521篇 |
1999年 | 422篇 |
1998年 | 176篇 |
1997年 | 137篇 |
1996年 | 126篇 |
1995年 | 139篇 |
1994年 | 82篇 |
1993年 | 97篇 |
1992年 | 220篇 |
1991年 | 197篇 |
1990年 | 187篇 |
1989年 | 196篇 |
1988年 | 153篇 |
1987年 | 180篇 |
1986年 | 136篇 |
1985年 | 142篇 |
1984年 | 118篇 |
1983年 | 102篇 |
1982年 | 72篇 |
1981年 | 71篇 |
1979年 | 103篇 |
1978年 | 68篇 |
1977年 | 76篇 |
1975年 | 68篇 |
1974年 | 56篇 |
1973年 | 58篇 |
1972年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
Reconstitution of T-cell repertoire after autologous stem cell transplantation: influence of CD34 selection and cytomegalovirus infection. 总被引:6,自引:0,他引:6
Karl S Peggs Stephanie Verfuerth Arnold Pizzey Naeem Khan Paul Moss Anthony H Goldstone Kwee Yong Stephen Mackinnon 《Biology of blood and marrow transplantation》2003,9(3):198-205
The period of immunodeficiency following autologous hematopoietic stem cell transplantation is characterized by transient expansions of CD8+CD45RO+CD57+ T lymphocytes, displaying markers of an activated phenotype. Most evidence suggests that this early reconstitution results from proliferation of mature T cells that have survived conditioning or were transferred with the graft. Although homeostatic mechanisms are thought to act in maintaining total T-cell numbers, the degree to which antigen-driven expansions contribute and the nature of the stimulating antigens remain unclear. CD34 selection of stem cell grafts reduces the available T-cell pool, potentially delaying immune reconstitution and resulting in increased infective complications. In the allogeneic transplantation setting, lymphopenia has been associated with cytomegalovirus (CMV) infection risk and, if persistent, with adverse outcome. We prospectively studied patients undergoing CD34-selected (n = 13) or unselected (n = 13) autologous hematopoeitic stem cell transplantation for immune reconstitution and CMV infection. No significant differences were demonstrated between graft types with respect to lymphocyte subset recovery, T-cell receptor beta-chain variable region spectratype diversity, or CMV DNA detection rates (45% versus 40%). CMV infection was associated with a trend toward higher rather than lower CD8+ counts at 6 weeks posttransplantation (P =.08) that became significant by 3 months (P=.007), and that was associated with decreased T-cell receptor beta-chain variable region spectratype diversity (P =.01). CMV-specific HLA-tetramer analysis demonstrated transient expansions with CDR3 lengths corresponding to those of some of the major posttransplantation T-cell expansions demonstrated by spectratype analysis suggesting that CMV-specific T cells contribute to the pattern of immune reconstitution. 相似文献
64.
Khurana KK Loosmann A Numann PJ Khan SA 《Archives of pathology & laboratory medicine》2000,124(3):378-381
BACKGROUND: According to recently published data, prophylactic mastectomy (PM) appears to prevent about 90% of the expected malignant neoplasms in women with a family history of breast cancer. OBJECTIVES: To identify the frequency of high-risk lesions in PM specimens and to determine occurrence of any new primary breast cancer following PM. DESIGN: We performed a retrospective study of women undergoing unilateral or bilateral PM. Medical charts and pathologic findings of 35 patients who underwent bilateral mastectomies at University Hospital, Syracuse, NY, from 1989 to 1996 were reviewed. Patients with biopsy-proven bilateral breast cancer were excluded. Patients were divided into 3 groups: (A) positive family history and no known breast cancer (n = 9), (B) positive family history and contralateral neoplasia (n = 13), and (C) negative family history and contralateral neoplasia (n = 13). These findings were compared with those found in reduction mammoplasty specimens from 10 women at standard risk of breast cancer. RESULTS: The mean age of the control group of women undergoing reduction mammoplasty was 38 years. The pathologic specimens demonstrated no significant pathologic findings in 9 and fibrocystic change in 1. In group A, the mean number of affected relatives was 3.1, and the mean age was 38 years. Two of these 9 women had atypical duct hyperplasia and 1 had atypical lobular hyperplasia in their breasts (ie, 33% with high-risk pathologic findings). Of the 13 group B women (mean age, 46.6 years; mean of 2.5 affected relatives and unilateral breast cancer), the contralateral PM specimen contained duct carcinoma in situ in one and invasive ductal cancer in a second (15% with occult malignant neoplasms). In 13 group C patients (mean age, 47.1 years), 3 (23.1%) of the contralateral PM specimens displayed atypical duct hyperplasia or atypical lobular hyperplasia. At a mean follow-up of 4.8 years, there have been no new breast malignant neoplasms in these 45 women. CONCLUSIONS: The occurrence of unilateral cancer in patients with family history of breast cancer is associated with a 15.4% probability of simultaneous occult malignant neoplasms in the contralateral breast. Patients with a strong family history but no evidence of breast cancer have a substantially similar rate of proliferative disease in their PM specimens as those women who have unilateral cancer but no significant family history. 相似文献
65.
Genetics of rheumatoid arthritis 总被引:4,自引:0,他引:4
H. Payami G. Thomson M. A. Khan D. M. Grennan P. Sanders P. Dyer C. Dostal 《Tissue antigens》1986,27(2):57-63
The haplotype sharing distribution in affected sib pairs are used to demonstrate the linkage of a susceptibility gene for rheumatoid arthritis (RA) to the HLA region. Family and population studies suggest heterogeneity in the etiology of RA. 相似文献
66.
67.
Krishna M Banner BF Puyana JC Khan A 《Archives of pathology & laboratory medicine》1996,120(10):981-984
Intraductal papillary mucinous neoplasms are rare pancreatic exocrine tumors with distinct clinicopathologic features. They usually present with a long history of chronic pancreatitis-like symptoms, which are often associated with weight loss, diarrhea, and malabsorption. We report a case of benign intraductal papillary mucinous neoplasm with focal squamous metaplasia presenting as acute necrotizing pancreatitis. The clinicopathologic features are discussed in a brief review of the literature. 相似文献
68.
Gamborino E Carrilho C Ferro J Khan MS Garcia C Suarez MC Yokoyama H Schmitt FC 《Diagnostic cytopathology》2000,23(5):322-325
Fine-needle aspiration (FNA) cytology was performed on 15 patients with peripheral lymphadenopathy and/or skin lesions referred to the Department of Pathology of the Hospital Central of Maputo, Maputo, Mozambique. Epitrochlear lymph nodes were the most frequently aspirated site. All aspirates allowed diagnoses of Kaposi's sarcoma (KS). Smears contained loosely cohesive clusters of bland spindle cells, with a radial arrangement and nuclear crush artifacts. These diagnostic clues have not been described in other spindle-cell intranodal lesions that should be considered in differential diagnoses. Taking into consideration the high prevalence of AIDS and limited resources for diagnosis in Africa, FNA cytology appears to be a useful method for the diagnosis of KS in developing countries, reducing the necessity for surgical lymph node excision. 相似文献
69.
Haseeb Khan Ahmad Saleh Al Deeb Khalaf Al Moutaery Mohammad Tariq 《Experimental and toxicologic pathology》2003,55(2-3):181-186
A direct association between aging and drug-induced dyskinesia has been reported by several investigators. Iminiodipropionitrile (IDPN), a prototype nitrile compound produces a motor syndrome in rodents, which resembles neuroleptic drug induced dyskinesia. In this investigation attempt has been made to study the effect of age on IDPN induced vestibular hair cell degeneration and resulting dyskinetic syndrome. Male Wistar rats aged 3, 6 and 12 weeks received IDPN in the doses of 0, 200 and 400 mg/kg, intraperitoneally for 3 consecutive days. IDPN-induced dyskinesia was assessed using a behavioral testing battery on days 3, 4, 5, 6, 7, 14, 21 and 28. The rats were sacrificed on day 28; temporal bones were excised for vestibular histopathology and sera were collected for measuring the indices of oxidative stress (glutathione and conjugated dienes). IDPN in the dose of 200 mg/kg produced dyskinesia in 12 weeks old rats, but failed to do so in 3 and 6 weeks old rats. The high dose of IDPN (400 mg/kg) caused dyskinesia in all age groups, however, its onset and severity were age-dependent. Older rats showed an early onset and significantly high incidence of dyskinesia as compared to younger rats. The susceptibility of rats to IDPN-induced behavioral deficits was proportional to oxidative stress and degeneration of sensory hair cells in the crista ampullaris. 相似文献
70.