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   208480篇
  免费   37014篇
  国内免费   2539篇
耳鼻咽喉   5616篇
儿科学   7131篇
妇产科学   3801篇
基础医学   11602篇
口腔科学   2872篇
临床医学   34021篇
内科学   59645篇
皮肤病学   8526篇
神经病学   20328篇
特种医学   8054篇
外国民族医学   4篇
外科学   48048篇
综合类   626篇
现状与发展   72篇
一般理论   30篇
预防医学   12514篇
眼科学   4074篇
药学   5144篇
中国医学   72篇
肿瘤学   15853篇
  2024年   739篇
  2023年   5329篇
  2022年   1705篇
  2021年   4269篇
  2020年   7099篇
  2019年   3653篇
  2018年   9314篇
  2017年   9023篇
  2016年   10159篇
  2015年   10019篇
  2014年   17405篇
  2013年   18822篇
  2012年   9726篇
  2011年   9814篇
  2010年   12717篇
  2009年   16231篇
  2008年   9550篇
  2007年   7802篇
  2006年   9985篇
  2005年   7099篇
  2004年   6069篇
  2003年   4829篇
  2002年   4816篇
  2001年   4987篇
  2000年   4360篇
  1999年   4118篇
  1998年   4122篇
  1997年   3845篇
  1996年   3656篇
  1995年   3499篇
  1994年   2247篇
  1993年   1831篇
  1992年   1708篇
  1991年   1722篇
  1990年   1336篇
  1989年   1456篇
  1988年   1323篇
  1987年   1104篇
  1986年   1162篇
  1985年   1032篇
  1984年   860篇
  1983年   774篇
  1982年   750篇
  1981年   592篇
  1980年   518篇
  1979年   492篇
  1978年   473篇
  1977年   544篇
  1975年   393篇
  1972年   378篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Objective. The objective of this study was to compare blood pressure (BP) measured by the sphygmooscillographic method with that measured by the direct and auscultatory methods.Methods. In 15 adult patients undergoing cardiac surgery, blood pressure was measured by the sphygmooscillographic and direct methods simultaneously on the same upper extremity. In another group of 86 children and 11 adults, blood pressure was measured by the sphygmooscillographic and auscultatory methods simultaneously, with one cuff. For the sphygmooscillographic measurement, we used sphygmomanometer-S, which measures blood pressure on the basis of the amplitude height (oscillometric) and the morphology (sphygmographic) of pulse waves recorded by a transducer placed in the cuff.Results. The systolic and diastolic blood pressure measured by the sphygmooscillographic method were both 2 mm Hg higher than those from the direct method; the mean blood pressure was 0.6 mm Hg higher. These differences were not significant. Compared with the auscultatory method, sphygmooscillographic systolic values were higher by 7 mm Hg, while diastolic values were lower by 9 mm Hg. These differences were significant.Conclusions. Blood pressure measurements obtained by the sphygmooscillographic method correlate well with the direct method for measuring blood pressure in children and adults; but, they do not correlate well with the auscultatory method.  相似文献   
992.
993.
994.
There has been considerable progress in the treatment of chronic hepatitis C since the first report that interferon (IFN) monotherapy was effective in 1989. Early results were meager, with sustained loss of hepatitis C virus from blood in fewer than 10% of cases. The combination of IFN with the oral nucleoside analogue ribavirin was a major breakthrough in clinical hepatology; it led to dramatic increases in treatment responses, with 30% to 40% of patients clearing virus. Pegylated IFNs that have prolonged activity and can be dosed once a week have now replaced standard IFNs. The combination of pegylated IFN with ribavirin is the new standard of care; it causes sustained loss of virus in more than half of treated patients. Treatment responses continue to be highly dependent on viral genotype. Patients with genotype 1, the most common type in the United States, have a sustained clearance rate of 42% to 46%, whereas those with genotype 2 or 3 have a response rate approaching 80%.  相似文献   
995.
Background: Studies have consistently confirmed the benefit of liver resection for metastatic colorectal cancer. Few reports, however, have a long enough followup or sufficient 5-year survivors to study the clinical course of patients beyond 5 years.

Study Design: From July 1985 through December 1991, 456 patients underwent liver resection for colorectal metastases. Ninety-six actual 5-year survivors (21%) were identified and their clinical course retrospectively reviewed.

Results: Five-year survivors (n = 96) were more likely to have a Duke’s B primary colorectal carcinoma, fewer than four metastatic lesions, unilobar disease, and a negative histologic margin when compared with patients not surviving 5 years (n = 298). Forty-four (46%) of the 96 five-year survivors had a recurrence after hepatectomy. Of these 44, 19 (43%) were rendered disease free after further treatment. Overall, 71 of the 96 five-year survivors were free of disease at last followup. The actuarial 10-year survival of this group was 78%.

Conclusions: Patients that are disease free 5 years after liver resection are likely to have been cured by liver resection. Patients should be aggressively followed for recurrence because of the potential for further treatment and longterm survival.  相似文献   

996.
997.
Background: We examined alternative methods of delivering cytokines as an adjunct for priming lymph node (LN) cells draining sites of vaccine inoculation for the purpose of generating immune cells for adoptive immunotherapy. Methods: Using syngeneic murine tumors we examined the ability of IL-2, IL-4, or GM-CSF delivered locally to a site of tumor inoculum to induce antitumor reactive draining LN cells. Mice were inoculated subcutaneously with tumor cells transduced to secrete cytokine; tumor cells admixed with fibroblasts transduced to secrete cytokine; or intralesional inoculation of cytokine in established tumor to induce sensitized LN cells capable of mediating tumor regression in adoptive transfer. Results: Both IL-4 and GM-CSF cytokines were effective in enhancing the antitumor reactivity of vaccine-primed LN cells compared to IL-2, which was ineffective. The local delivery of GM-CSF by autocrine or paracrine secretion of genetically engineered cells, as well as direct intratumoral delivery was capable of upregulating LN sensitization compared to systemic administration, which did not. Conclusions: The local delivery of GM-CSF as an adjuvant for tumor vaccination can be accomplished by various methods, including direct injection, which avoids the need for gene transfer.  相似文献   
998.
999.
1000.
We report studies on the complement sensitivity of four strains of Yersinia enterocolitica , serotypes O:3, O:9, O:5,27, and O:20, isolated from blood units involved in transfusion fatalities. Complement in fresh CPD plasma killed Y. enterocolitica within 4 h at 22°C in 100% of the experiments. The bactericidal action was serotype and complement activation pathway dependent. Both classic and alternate pathways seemed to be active, but the latter to a lesser degree. When the classic pathway was blocked by chelation of Ca2+ no complete killing was obtained. Complement did not enhance or condition Yersinia for leucocyte filter retention. Direct removal of Yersinia by filtration was also related to serotype; all strains were reduced by filtration in heat-inactivated plasma, and all except serotype O:5,27 were reduced in Ca2+ -chelated plasma. Our findings may explain why plasma products and platelet concentrates are rarely involved in Yersinia sepsis related to transfusion.  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