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   4473篇
  免费   337篇
  国内免费   16篇
耳鼻咽喉   38篇
儿科学   66篇
妇产科学   96篇
基础医学   691篇
口腔科学   15篇
临床医学   773篇
内科学   1087篇
皮肤病学   81篇
神经病学   349篇
特种医学   164篇
外科学   473篇
综合类   16篇
一般理论   2篇
预防医学   371篇
眼科学   32篇
药学   286篇
中国医学   7篇
肿瘤学   279篇
  2023年   15篇
  2022年   45篇
  2021年   73篇
  2020年   32篇
  2019年   77篇
  2018年   92篇
  2017年   51篇
  2016年   85篇
  2015年   112篇
  2014年   178篇
  2013年   208篇
  2012年   352篇
  2011年   371篇
  2010年   195篇
  2009年   178篇
  2008年   347篇
  2007年   329篇
  2006年   291篇
  2005年   355篇
  2004年   342篇
  2003年   309篇
  2002年   260篇
  2001年   39篇
  2000年   32篇
  1999年   51篇
  1998年   67篇
  1997年   31篇
  1996年   37篇
  1995年   33篇
  1994年   25篇
  1993年   32篇
  1992年   19篇
  1991年   25篇
  1990年   17篇
  1989年   11篇
  1988年   17篇
  1987年   14篇
  1986年   5篇
  1985年   8篇
  1984年   5篇
  1983年   6篇
  1982年   11篇
  1981年   8篇
  1980年   9篇
  1979年   3篇
  1978年   4篇
  1977年   5篇
  1974年   5篇
  1972年   3篇
  1971年   3篇
排序方式: 共有4826条查询结果,搜索用时 15 毫秒
71.
72.
The first aim of this study was to assess the diagnostic performance of presepsin (sCD14-ST) in postmortem serum from femoral blood compared to procalcitonin (PCT) to detect sepsis-related fatalities. The second aim was to compare sCD14-ST levels found in postmortem serum to the values in pericardial fluid to investigate the usefulness of the latter as an alternative biological fluid. Two study groups were formed, a sepsis-related fatalities group and a control group. Radiology (unenhanced CT scans and postmortem angiographies), autopsies, histology, neuropathology, and toxicology as well as other postmortem biochemistry investigations were performed in all cases. Microbiological investigations on right cardiac blood were carried out exclusively in septic cases. The results of this study indicated that postmortem serum PCT and sCD14-ST levels, individually considered, allowed septic cases to be identified. Even though increases in both PCT and sCD14-ST concentrations were observed in the control cases, coherent PCT and sCD14-ST results in cases with suspected sepsis allowed the diagnosis to be confirmed. Conversely, no relevant correlation was identified between postmortem serum and pericardial fluid sCD14-ST levels in either the septic or control groups.  相似文献   
73.
Antiphospholipid syndrome (APS) is characterized by recurrent thrombosis and pregnancy morbidity in association with the persistent presence of circulating antiphospholipid antibodies (aPL). APS remains the most frequent cause of acquired hypercoagulability and recurrent miscarriage. Long-term anticoagulation therapy is the only treatment with proven benefit in the APS. Anticoagulation is not effective in all patients and carries a risk of bleeding. Recent improvements in the understanding of the pathogenic mechanisms have led to the identification of potential targets and future therapies for APS. In contrast to non-specific anticoagulation, the emergence of immunomodulatory drugs provides the possibility of interfering with specific pathogenic pathways. Novel therapies might be used in the future for APS.  相似文献   
74.
BackgroundThe influence of genetic predictors of inflammation and atopy on occupational asthma in apprentices is not known.ObjectivesTo assess the influence of genetic polymorphisms of IL4RA, IL13, TNFA, IL1A, and IL5 on the decline of lung function and bronchial hyperresponsiveness in a prospective follow-up study of baker/pastry maker and hairdresser apprentices.MethodsA total of 351 apprentices were included in the study. We performed skin testing, spirometry, fractional exhaled nitric oxide measurement, and methacholine hyperreactivity testing at the initial visit and during and at the end of the 18-month training period. Gene variants of IL4RA, IL13, TNFA, IL1A, and IL5 were determined in DNA from nasal lavage.ResultsIL13 R130Q/IL4RA S478P or IL13 R130Q//IL4RA Q551R were significant predictors of the decrease of forced expiratory volume and forced vital capacity (P ≤ .006). Genotype GG of TNFAG308A was associated with bronchial hyperresponsiveness in the whole population and in nonatopic individuals (90.63% vs 9.38%; odds ratio, 3.78; 95% confidence interval, 1.10-12.83). TNFA GA and IL5 CC and TNFA GA and IL1A CC were 2 epistatic predictors of exhaled nitrogen monoxide decrease during follow-up (P = .02 and P = .004, respectively). The association with TNFA GA and IL1A CC was the most significant in nonatopic bakers (P < .001).ConclusionWe evidenced a predicting influence of IL13/IL4RA and TNFA in the early exposure to allergens and irritants that precedes occupational asthma. The significance of the associations in the absence of atopy suggests an influence of the genetics predictors related to inflammatory pathways.  相似文献   
75.
76.
Cysteamine is approved for the treatment of cystinosis and is being evaluated for Huntington's disease and non‐alcoholic fatty liver disease. Little is known about the bioavailability and biodistribution of the drug. The aim was to determine plasma, cerebrospinal fluid (CSF), and tissue (liver, kidney, muscle) cysteamine levels following intraduodenal delivery of the drug in rats pretreated and naïve to cysteamine and to estimate the hepatic first‐pass effect on cysteamine. Healthy male rats (n = 66) underwent intraduodenal and portal (PV) or jugular (JVC) venous catheterization. Half were pretreated with cysteamine, and half were naïve. Following intraduodenal cysteamine (20 mg/kg), serial blood samples were collected from the PV or the JVC. Animals were sacrificed at specific time points, and CSF and tissue were collected. Cysteamine levels were determined in plasma, CSF, and tissue. The Cmax was achieved in 5–10 min from PV and 5–22.5 min from JVC. The PV‐Cmax (P = 0.08), PV‐AUC0–t (P = 0.16), JVC‐Cmax (P = 0.02) and JVC‐AUC0–t (P = 0.03) were higher in naive than in pretreated animals. Plasma cysteamine levels returned to baseline in ≤120 min. The hepatic first‐pass effect was estimated at 40%. Peak tissue and CSF cysteamine levels occurred ≤22.5 min, but returned to baseline levels ≤180 min. There was no difference in CSF and tissue cysteamine levels between naïve and pretreated groups, although cysteamine was more rapidly cleared in the pretreated group. Cysteamine is rapidly absorbed from the small intestine, undergoes significant hepatic first‐pass metabolism, crosses the blood brain barrier, and is almost undetectable in plasma, CSF, and body tissues 2 h after ingestion. Sustained‐release cysteamine may provide prolonged tissue exposure.  相似文献   
77.
78.
The process of “adaptive suckling” has evolved appropriate to the needs of different mammal species. It is related to the maturity of the newborn, nutritional requirements, the number of offspring, the need for sensory stimulation, etc. Examples are given of the following species—the echidna, the kangaroo, the blue whale and.the seal. Its relevance to modern man is discussed.  相似文献   
79.
A prospective survey was conducted on 862 Enterobacteriaceae isolates with reduced susceptibility to carbapenems. The Carba NP test, UV spectrophotometry, and a DNA microarray were used to detect carbapenemase producers, and the results were compared to those from PCR and sequencing. The 172 carbapenemase producers were detected using the Carba NP test and UV spectrophotometry, whereas the DNA microarray failed to detect IMI producers. The use of the Carba NP test as a first screening, followed by the use of molecular techniques, has been determined to be an efficient strategy for identifying carbapenemase-producing Enterobacteriaceae.  相似文献   
80.
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