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   5668篇
  免费   263篇
  国内免费   11篇
耳鼻咽喉   48篇
儿科学   219篇
妇产科学   139篇
基础医学   571篇
口腔科学   61篇
临床医学   340篇
内科学   1399篇
皮肤病学   115篇
神经病学   419篇
特种医学   276篇
外科学   1093篇
综合类   155篇
一般理论   1篇
预防医学   179篇
眼科学   270篇
药学   393篇
中国医学   15篇
肿瘤学   249篇
  2023年   46篇
  2022年   86篇
  2021年   186篇
  2020年   87篇
  2019年   124篇
  2018年   158篇
  2017年   108篇
  2016年   147篇
  2015年   166篇
  2014年   220篇
  2013年   255篇
  2012年   412篇
  2011年   427篇
  2010年   244篇
  2009年   200篇
  2008年   332篇
  2007年   355篇
  2006年   327篇
  2005年   281篇
  2004年   297篇
  2003年   244篇
  2002年   212篇
  2001年   118篇
  2000年   100篇
  1999年   75篇
  1998年   53篇
  1997年   31篇
  1996年   23篇
  1995年   21篇
  1994年   18篇
  1993年   20篇
  1992年   44篇
  1991年   38篇
  1990年   44篇
  1989年   35篇
  1988年   28篇
  1987年   31篇
  1986年   36篇
  1985年   26篇
  1984年   34篇
  1983年   26篇
  1982年   20篇
  1979年   14篇
  1978年   16篇
  1977年   15篇
  1975年   13篇
  1974年   13篇
  1973年   13篇
  1968年   13篇
  1967年   13篇
排序方式: 共有5942条查询结果,搜索用时 15 毫秒
31.
A reply     
S. Malhotra  S. M. Yentis 《Anaesthesia》2007,62(12):1298-1298
  相似文献   
32.
Community-acquired viral respiratory tract infections (RTI) in lung transplant recipients may have a high rate of progression to pneumonia and can be a trigger for immunologically mediated detrimental effects on lung function. A cohort of 100 patients was enrolled from 2001 to 2003 in which 50 patients had clinically diagnosed viral RTI and 50 were asymptomatic. All patients had nasopharyngeal and throat swabs taken for respiratory virus antigen detection, culture and RT-PCR. All patients had pulmonary function tests at regular intervals for 12 months. Rates of rejection, decline in forced expiratory volume (L) in 1 s (FEV-1) and bacterial and fungal superinfection were compared at the 3-month primary endpoint. In the 50 patients with RTI, a microbial etiology was identified in 33 of 50 (66%) and included rhinovirus (9), coronavirus (8), RSV (6), influenza A (5), parainfluenza (4) and human metapneumovirus (1). During the 3-month primary endpoint, 8 of 50 (16%) RTI patients had acute rejection versus 0 of 50 non-RTI patients (p=0.006). The number of patients experiencing a 20% or more decline in FEV-1 by 3 months was 9 of 50 (18%) RTI versus 0 of 50 non-RTI (0%) (p=0.003). In six of these nine patients, the decline in FEV-1 was sustained over a 1-year period consistent with bronchiolitis obliterans syndrome (BOS). Community-acquired respiratory viruses may be associated with the development of acute rejection and BOS.  相似文献   
33.
Calcineurin inhibitor (CNI) withdrawal has been used as a strategy to improve renal allograft function, however, it also carries risk of acute rejection. We conducted a systematic review of randomized trials that involved CNI withdrawal from a sirolimus-based immunosuppressive regimen. The search strategy yielded six trials (n = 1047 patients) reported in eight publications. CNI withdrawal from sirolimus-based therapy, was associated with an increased risk of acute rejection (risk difference, 6%; 95% CI 2-10%, p = 0.002) but a higher creatinine clearance (mean difference, 7.49 mL/min; 95% CI 5.08-9.89 mL/min, p < 0.00001) at 1 year compared to continued CNI and sirolimus therapy. Graft loss (relative risk, 0.87; 95% CI 0.46-1.64, p = 0.66) and death (relative risk, 0.88; CI 0.40-1.96, p = 0.76) were similar in both groups at 1 year. Hypertension was significantly reduced in the CNI withdrawal group (relative risk, 0.56; 95% CI 0.40-0.78, p = 0.0006). CNI withdrawal from sirolimus-based therapy is associated with an increased risk of acute rejection in the short term with a significant improvement in renal function and a reduction in hypertension. Longer follow-up is needed to determine if these changes will result in a significant improvement in patient and graft survival.  相似文献   
34.
35.
Aberrant epididymal tissue: a significant clinical entity   总被引:1,自引:0,他引:1  
  相似文献   
36.
37.
Cryptococcus neoformans is an opportunistic pathogen in AIDS patients causing disseminated disease and lethal meningitis after inhalation of acapsular or sparsely encapsulated yeast cells. In this study we have investigated whether a recently described family of primitive opsonins, termed collectins, contribute to innate resistance against C. neoformans. The pulmonary surfactant proteins SP-A and SP-D as well as the serum collectins mannose-binding protein and CL-43 bound in a calcium-dependent manner to acapsular C. neoformans in vitro. Binding was concentration dependent and abolished by competition with defined mono- and oligosaccharides. In contrast, no binding of the collectins was observed with the encapsulated form of the yeast. Furthermore, binding of purified collectin SP-D, but not SP-A, mannose-binding protein, or CL-43, led to a concentration-dependent agglutination of acapsular C. neoformans. These data indicate that collectins recognize carbohydrate structures in the cell wall of an initial infectious form of C. neoformans and may play a role in early antifungal defenses in the lung.  相似文献   
38.
Summary Serum samples from eight endogamous Indian tribal populations of Madhya Pradesh (Dhurwa, Halba, Bhatra, Muria, Maria) and Orissa (Deshia Khond, Binjhal, Kisan) with a total of n=731 unrelated individuals were typed for G1M (1,2,3,17), G3M (5,10,11,13,14,15,16,21,26), and KM (1). In seven of these populations five different GM haplotypes were found:GM*1,17;21,26; GM*1,17;10,11,13,15,16; GM*1,2,17;21,26; GM*1,3;5,10,11,13,14,26; andGM*3;5,10,11,13,14,26. In the Kisan sample the haplotypeGM*1,2,17; 21,26 is absent. The intergroup variability in the distribution of these haplotypes is considerable and statistically highly significant. The reasons for that can be attributed to the ethnohistory and to the genetic isolation of these eight endogamous tribal populations. The GM haplotype distribution pattern of all these groups is quite different from that of the non-tribal populations of India, whereas it is in good agreement with that of the so far tested other tribal populations from India. This can be explained by different origin and history of the Indian tribal and non-tribal populations. In the KM system, too, remarkable variability is seen in the distribution of phenotype and allele frequencies among the eight tribal populations under study.  相似文献   
39.
40.
Renal involvement as the first manifestation of sarcoidosis is rare and has never been reported in India. This report describes a 35 year old man who was admitted to the emergency department with a clinical diagnosis of acute on chronic renal failure, secondary to obstructive uropathy. Postmortem examination unexpectedly revealed disseminated sarcoidosis.  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