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   11020篇
  免费   905篇
  国内免费   165篇
耳鼻咽喉   87篇
儿科学   445篇
妇产科学   315篇
基础医学   1471篇
口腔科学   239篇
临床医学   1126篇
内科学   2484篇
皮肤病学   146篇
神经病学   711篇
特种医学   361篇
外科学   1402篇
综合类   383篇
一般理论   10篇
预防医学   763篇
眼科学   274篇
药学   788篇
中国医学   205篇
肿瘤学   880篇
  2023年   62篇
  2022年   105篇
  2021年   255篇
  2020年   148篇
  2019年   246篇
  2018年   267篇
  2017年   216篇
  2016年   219篇
  2015年   285篇
  2014年   355篇
  2013年   462篇
  2012年   761篇
  2011年   773篇
  2010年   440篇
  2009年   417篇
  2008年   692篇
  2007年   664篇
  2006年   688篇
  2005年   613篇
  2004年   536篇
  2003年   462篇
  2002年   410篇
  2001年   395篇
  2000年   396篇
  1999年   315篇
  1998年   118篇
  1997年   86篇
  1996年   86篇
  1995年   74篇
  1994年   54篇
  1993年   65篇
  1992年   178篇
  1991年   149篇
  1990年   138篇
  1989年   145篇
  1988年   129篇
  1987年   119篇
  1986年   114篇
  1985年   93篇
  1984年   64篇
  1983年   45篇
  1982年   37篇
  1981年   30篇
  1980年   25篇
  1979年   33篇
  1978年   17篇
  1977年   19篇
  1976年   14篇
  1974年   14篇
  1972年   11篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
A proinflammatory role for IL-18 in rheumatoid arthritis   总被引:63,自引:0,他引:63       下载免费PDF全文
IL-18 is a novel cytokine with pleiotropic activities critical to the development of T-helper 1 (Th1) responses. We detected IL-18 mRNA and protein within rheumatoid arthritis (RA) synovial tissues in significantly higher levels than in osteoarthritis controls. Similarly, IL-18 receptor expression was detected on synovial lymphocytes and macrophages. Together with IL-12 or IL-15, IL-18 induced significant IFN-gamma production by synovial tissues in vitro. IL-18 independently promoted GM-CSF and nitric oxide production, and it induced significant TNF-alpha synthesis by CD14(+) macrophages in synovial cultures; the latter effect was potentiated by IL-12 or IL-15. TNF-alpha and IFN-gamma synthesis was suppressed by IL-10 and TGF-beta. IL-18 production in primary synovial cultures and purified synovial fibroblasts was, in turn, upregulated by TNF-alpha and IL-1beta, suggesting that monokine expression can feed back to promote Th1 cell development in synovial membrane. Finally, IL-18 administration to collagen/incomplete Freund's adjuvant-immunized DBA/1 mice facilitated the development of an erosive, inflammatory arthritis, suggesting that IL-18 can be proinflammatory in vivo. Together, these data indicate that synergistic combinations of IL-18, IL-12, and IL-15 may be of importance in sustaining both Th1 responses and monokine production in RA.  相似文献   
992.
Mouse B7-H3 induces antitumor immunity   总被引:16,自引:0,他引:16  
Sun X  Vale M  Leung E  Kanwar JR  Gupta R  Krissansen GW 《Gene therapy》2003,10(20):1728-1734
Members of the B7 family costimulate the proliferation of lymphocytes during the initiation and maintenance of antigen-specific humoral and cell-mediated immune responses. While B7-1 and -2 are restricted to lymphoid tissues, and activate na?ve T cells, recently identified members including B7-H2 and -H3 are widely expressed on nonlymphoid tissues, and regulate effector lymphocytes in the periphery. B7-H3 has properties that suggested it may display antitumor activity, including the ability to stimulate Th1 and cytotoxic T-cell responses. Here, we test this notion by determining whether intratumoral injection of an expression plasmid encoding a newly described mouse homologue of B7-H3 is able to eradicate EL-4 lymphomas. Intratumoral injection of a mouse B7-H3 pcDNA3 expression plasmid led to complete regression of 50% tumors, or otherwise significantly slowed tumor growth. Mice whose tumors completely regressed resisted a challenge with parental tumor cells, indicating systemic immunity had been generated. B7-H3-mediated antitumor immunity was mediated by CD8(+) T and NK cells, with no apparent contribution from CD4(+) T cells. In summary, the results indicate that B7-H3 interactions may play a role in regulating cell-mediated immune responses against cancer, and that B7-H3 is a potential therapeutic tool.  相似文献   
993.
Group A β-hemolytic streptococcal pharyngitis in children   总被引:2,自引:0,他引:2  
Group A β-hemolytic streptococcus (GABHS) is the most common bacterial cause of acute pharyngitis in children. Because clinical findings can be nonspecific, even experienced physicians cannot reliably diagnose GABHS pharyngitis solely on the basis of clinical presentation. Suspected cases should be confirmed by a throat culture or a rapid antigen detection test before antibiotic therapy is initiated. Microbiologic testing is generally not necessary in patients with pharyngitis whose clinical and epidemiologic findings are not suggestive of GABHS. Clinical score systems have been developed to help physicians decide which patients should undergo diagnostic testing and to reduce the unnecessary use of antibiotics. Antibiotic therapy should be initiated as soon as the diagnosis is confirmed. Penicillin V remains the drug of choice. Alternative therapy, eg, with cephalosporin or macrolide, is often sought because of penicillin allergy, noncompliance, and treatment failure.  相似文献   
994.
995.
996.
997.
998.
OBJECTIVE AND SAMPLE: This paper reports on the learning experience of 88 Chinese older adults who attended a health Web-navigating workshop. DESIGN: Through a 3-hr training workshop, participants were guided to browse through seven health Web sites that provide authoritative health information by the Hong Kong government, academic institutions, or professional bodies. METHODS: Upon completion of the workshop, an evaluation was made of the participants' confidence in navigating health Web sites by themselves at home and in utilizing the health information sources. RESULTS: The findings indicated that participants' confidence in seeking health information via the Internet was not associated with their age, educational level, or experience of using computers before the workshop but was significantly associated with their satisfaction with the workshop (p<.05). Significant change of source of health information was noted at follow-up, suggesting that the workshop was successful. CONCLUSIONS: Implications of the results for running health Web-navigating programs among Chinese older adults are discussed.  相似文献   
999.
Hematopoietic stem cell transplantation (HSCT) is the only curative option for a subset of patients with high-risk or relapsed acute lymphoblastic leukemia (ALL). Given evolving practices, it is important to continually evaluate outcomes for pediatric ALL following HSCT. Outcomes after HSCT are influenced by the type of donor used as this determines the degree and method of T cell depletion used and, consequently, specific transplant-related morbidities. We retrospectively analyzed HSCT data from our center for transplants performed between January 2008 and May 2016, comparing outcomes among different donor types. One hundred and twenty-four pediatric patients underwent HSCT from a matched sibling donor (MSD; n?=?48), an unrelated matched donor (UMD; n?=?56), or a haploidentical donor (n?=?20). We observed a similar 3-year event-free survival (EFS) for MSD recipients (of .64) and for UMD recipients (.62), but a significantly lower EFS for recipients of haploidentical transplants (.35; P?=?.01). Relapse was the main cause of HSCT failure and was significantly higher in the haploidentical donor group (.47 versus .19 for MSD and .24 for UMD; P?=?.02). Treatment-related mortality was evenly distributed among the donor groups (.17, .16, and .15 for the MSD, UMD, and haploidentical groups, respectively). Rates of infection-related mortality were lower than previously reported. Relapse is the main obstacle for successful HSCT in the contemporary era, and this effect is most evident in recipients of haploidentical donor grafts. Newer methods to improve graft-versus-leukemia effect are being evaluated and will need to be incorporated into the management of high-risk patients.  相似文献   
1000.
Common variable immunodeficiency (CVID) is a primary B-cell immunodeficiency disorder, characterized by remarkable hypogammaglobulinemia. The disease can develop at any age without gender predominance. The prevalence of CVID varies widely worldwide. The underlying causes of CVID remain largely unknown; primary B-cell dysfunctions, defects in T cells and antigen-presenting cells are involved. Although some monogenetic defects have been identified in some CVID patients, it is likely that CVID is polygenic. Patients with CVID develop recurrent and chronic infections (e.g., bacterial infections of the respiratory or gastrointestinal tract), autoimmune diseases, lymphoproliferation, malignancies, and granulomatous lesions. Interestingly, autoimmunity can be the only clinical manifestation of CVID at the time of diagnosis and may even develop prior to hypogammaglobulinemia. The diagnosis of CVID is largely based on the criteria established by European Society for Immunodeficiencies and Pan-American Group for Immunodeficiency (ESID/PAGID) and with some recent modifications. The disease can affect multiple organs, including the liver. Clinical features of CVID patients with liver involvement include abnormal liver biochemistries, primarily elevation of alkaline phosphatase (ALP), nodular regenerative hyperplasia (NRH), or liver cirrhosis and its complications. Replacement therapy with immunoglobulin (Ig) and anti-infection therapy are the primary treatment regimen for CVID patients. No specific therapy for liver involvement of CVID is currently available, and liver transplantation is an option only in select cases. The prognosis of CVID varies widely. Further understanding in the etiology and pathophysiology will facilitate early diagnosis and treatments to improve prognosis.  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