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   4752篇
  免费   285篇
  国内免费   24篇
耳鼻咽喉   51篇
儿科学   131篇
妇产科学   78篇
基础医学   580篇
口腔科学   442篇
临床医学   374篇
内科学   1054篇
皮肤病学   77篇
神经病学   312篇
特种医学   249篇
外科学   536篇
综合类   17篇
预防医学   534篇
眼科学   83篇
药学   336篇
中国医学   25篇
肿瘤学   182篇
  2023年   41篇
  2022年   133篇
  2021年   175篇
  2020年   134篇
  2019年   148篇
  2018年   188篇
  2017年   126篇
  2016年   118篇
  2015年   185篇
  2014年   233篇
  2013年   239篇
  2012年   346篇
  2011年   425篇
  2010年   237篇
  2009年   156篇
  2008年   264篇
  2007年   287篇
  2006年   215篇
  2005年   219篇
  2004年   152篇
  2003年   120篇
  2002年   116篇
  2001年   86篇
  2000年   84篇
  1999年   64篇
  1998年   31篇
  1997年   35篇
  1996年   48篇
  1995年   23篇
  1994年   30篇
  1993年   19篇
  1992年   39篇
  1991年   40篇
  1990年   23篇
  1989年   36篇
  1988年   31篇
  1987年   17篇
  1986年   30篇
  1985年   29篇
  1984年   22篇
  1983年   15篇
  1982年   16篇
  1981年   7篇
  1980年   6篇
  1979年   6篇
  1978年   8篇
  1977年   11篇
  1976年   11篇
  1975年   9篇
  1971年   6篇
排序方式: 共有5061条查询结果,搜索用时 46 毫秒
51.
52.
53.
The PstS1 antigen is highly immunogenic, principally when combined with CFP10 during both latent and active TB infection. In the present study, a selected pstS1 gene fragment was cloned, fused with CFP10, and expressed in Escherichia coli. The product [PstS-1(285-374):CFP10] was compared to the recombinant fused RD1 (region of deletion 1) protein (ESAT-6:CFP10) in detecting Mycobacterium tuberculosis infection in 108 recent contacts of pulmonary tuberculosis (TB) cases, considering a positive tuberculin skin test (TST) to be the baseline. The release of gamma interferon (IFN-γ) in 22-h whole-blood and 5-day lymphocyte stimulation assays primed with each antigen was determined. All contacts were clinically followed for up to 1 year, and 87% of the tuberculin skin test-positive (TSTpositive) patients accepted preventative treatment. Concerning the IFN-γ response to PstS-1(285-374):CFP10 in the 22-h and 5-day assays, a slight increase in contact-TSTpositive detection was observed (23/54 and 26/54) compared to the level seen with the RD1 protein (18/54 and 24/54) whereas in the TSTnegative group, similarly lower numbers (≤5/48) of responders were achieved for both antigens, except for RD1 in the 5-day assay (8/48). By combining the IFN-γ responders to both antigens in the 5-day assays, slightly higher increases in positivity were found in the TSTpositive (32/54) and TSTnegative (10/48) groups. Two of 12 untreated TSTpositive contacts progressed to active TB and were concordantly positive in all assays, except for one contact who lacked positivity in the RD1 5-day assay. We demonstrated for the first time that PstS-1(285-374):CFP10 slightly increased contact positivity and detection of active disease progression, suggesting its potential application as a TB infection marker.  相似文献   
54.
Cutaneous larva migrans is a pruritic dermatitis due to the inoculation of helminths larvae in the skin, and it often occurs in children in tropical and subtropical areas. The authors describe an atypical case of cutaneous larva migrans in a 11 year-old child with scalp involvement, an unusual topography for this lesion.  相似文献   
55.
56.
57.
Homocysteine is a sulfur-containing amino acid derived from methionine metabolism. When plasma homocysteine levels exceed 10–15 μM, there is a condition known as hyperhomocysteinemia, which occur as a result of an inborn error of methionine metabolism or by non-genetic causes. Mild hyperhomocysteinemia is considered a risk factor for development of neurodegenerative diseases. The objective of the present study was to evaluate whether acetylsalicylic acid has neuroprotective role on the effect of homocysteine on inflammatory, oxidative/nitrative stress, and morphological parameters in cerebral cortex of rats subjected to chronic mild hyperhomocysteinemia. Wistar male rats received homocysteine (0.03 μmol/g of body weight) by subcutaneous injections twice a day and acetylsalicylic acid (25 mg/Kg of body weight) by intraperitoneal injections once a day from the 30th to the 60th postpartum day. Control rats received vehicle solution in the same volume. Results showed that rats subjected to chronic mild hyperhomocysteinemia significantly increased IL-1β, IL-6, and acetylcholinesterase activity and reduced nitrite levels. Homocysteine decreased catalase activity and immunocontent and superoxide dismutase activity, caused protein and DNA damage, and altered neurons ultrastructure. Acetylsalicylic acid totally prevented the effect of homocysteine on acetylcholinesterase activity and catalase activity and immunocontent, as well as the ultrastructural changes, and partially prevented alterations on IL-1β levels, superoxide dismutase activity, sulfhydryl content, and comet assay. Acetylsalicylic acid per se increased DNA damage index. In summary, our findings showed that chronic chemically induced model of mild hyperhomocysteinemia altered some parameters and acetylsalicylic acid administration seemed to be neuroprotective, at least in part, on neurotoxicity of homocysteine.  相似文献   
58.
Prostatic artery embolization requires a refined technique to achieve good imaging and clinical success. The PErFecTED (Proximal Embolization First, Then Embolize Distal) technique has produced greater prostate ischemia and infarction than previously described methods with clinical improvement of lower urinary symptoms and lower recurrence rates. The microcatheter should cross any collateral branch to the bladder, rectum, corpus cavernosum, gonad, or penis and be placed distally into the prostatic artery before its branching to the central gland and peripheral zone. This technique allows better distribution of embolic material in the intraprostatic arteries and reduces risk of spasm or thrombus. Because benign prostatic hyperplasia develops primarily in the periurethral region of the prostate, the urethral group of arteries should be embolized first. Subsequent distal investigation and embolization completes occlusion and stasis of blood flow to the prostatic parenchyma. Since we added the second step to the PErFecTED technique, we have observed infarcts in all patients submitted to prostatic artery embolization.  相似文献   
59.
60.
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