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   5081篇
  免费   243篇
  国内免费   21篇
耳鼻咽喉   72篇
儿科学   398篇
妇产科学   42篇
基础医学   439篇
口腔科学   92篇
临床医学   321篇
内科学   1192篇
皮肤病学   94篇
神经病学   248篇
特种医学   160篇
外科学   1044篇
综合类   155篇
一般理论   1篇
预防医学   197篇
眼科学   234篇
药学   267篇
中国医学   23篇
肿瘤学   366篇
  2023年   30篇
  2022年   82篇
  2021年   198篇
  2020年   99篇
  2019年   121篇
  2018年   153篇
  2017年   126篇
  2016年   137篇
  2015年   152篇
  2014年   222篇
  2013年   311篇
  2012年   385篇
  2011年   343篇
  2010年   211篇
  2009年   217篇
  2008年   355篇
  2007年   251篇
  2006年   234篇
  2005年   224篇
  2004年   194篇
  2003年   166篇
  2002年   158篇
  2001年   97篇
  2000年   94篇
  1999年   84篇
  1998年   38篇
  1997年   30篇
  1996年   24篇
  1995年   19篇
  1994年   20篇
  1993年   24篇
  1992年   46篇
  1991年   53篇
  1990年   44篇
  1989年   55篇
  1988年   44篇
  1987年   24篇
  1986年   39篇
  1985年   30篇
  1984年   23篇
  1983年   13篇
  1981年   17篇
  1979年   22篇
  1978年   9篇
  1976年   12篇
  1975年   12篇
  1973年   12篇
  1971年   9篇
  1970年   10篇
  1969年   18篇
排序方式: 共有5345条查询结果,搜索用时 15 毫秒
71.
72.
73.
Opinion statement Biliary sludge is usually seen on transabdominal sonography as low-level echoes that layer in the dependent portion of the gallbladder without acoustic shadowing. Synonyms for biliary sludge include microlithiasis, biliary sand or sediment, pseudolithiasis, and microcrystalline disease. In most patients, biliary sludge is composed of calcium bilirubinate and cholesterol monohydrate crystals. A variety of predisposing factors are associated with biliary sludge formation. In most of these patients, removal of the risk factor can lead to resolution of sludge. In asymptomatic patients, biliary sludge can be managed expectantly. In patients who develop biliary-type pain, cholecystitis, cholangitis, or pancreatitis, the treatment of choice is cholecystectomy for those who can tolerate surgery. In patients who are not operative candidates, endoscopic sphincterotomy can prevent further episodes of cholangitis and pancreatitis, whereas medical therapy with ursodeoxycholic acid can prevent sludge formation and recurrent acute pancreatitis.  相似文献   
74.
The effects of oral treatment with coenzyme Q10 (120 mg/d) were compared for 28 days in 73 (intervention group A) and 71 (placebo group B) patients with acute myocardial infarction (AMI). After treatment, angina pectoris (9.5 vs. 28.1), total arrhythmias (9.5% vs. 25.3%), and poor left ventricular function (8.2% vs. 22.5%) were significantly (P < 0.05) reduced in the coenzyme Q group than placebo group. Total cardiac events, including cardiac deaths and nonfatal infarction, were also significantly reduced in the coenzyme Q10 group compared with the placebo group (15.0% vs. 30.9%, P < 0.02). The extent of cardiac disease, elevation in cardiac enzymes, and oxidative stress at entry to the study were comparable between the two groups. Lipid peroxides, diene conjugates, and malondialdehyde, which are indicators of oxidative stress, showed a greater reduction in the treatment group than in the placebo group. The antioxidants vitamin A, E, and C and beta-carotene, which were lower initially after AMI, increased more in the coenzyme Q10 group than in the placebo group. These findings suggest that coenzyme Q10 can provide rapid protective effects in patients with AMI if administered within 3 days of the onset of symptoms. More studies in a larger number of patients and long-term follow-up are needed to confirm our results.  相似文献   
75.
76.
Titanium carbide (TiC) reinforced nickel (Ni) matrix composites were processed via mechanical alloying (MA) followed by spark plasma sintering (SPS) process. Mechanical alloying has gained special attention as a powerful non-equilibrium process for fabricating amorphous and nanocrystalline materials, whereas spark plasma sintering (SPS) is a unique technique for processing dense and near net shape bulk alloys with homogenous microstructure. TiC reinforcement varied from 5 to 50 wt.% into nickel matrix to investigate its effect on the microstructure and mechanical behavior of Ni-TiC composites. All Ni-TiC composites powder was mechanically alloyed using planetary high energy ball mill with 400 rpm and ball to powder ratio (BPR) 15:1 for 24 h. Bulk Ni-TiC composites were then sintered via SPS process at 50 MPa pressure and 900–1200 °C temperature. All Ni-TiC composites exhibited higher microhardness and compressive strength than pure nickel due to the presence of homogeneously distributed TiC particles within the nickel matrix, matrix grain refinement, and excellent interfacial bonding between nickel and TiC reinforcement. There is an increase in Ni-TiC composites microhardness with an increase in TiC reinforcement from 5 to 50 wt.%, and it reaches the maximum value of 900 HV for Ni-50TiC composites.  相似文献   
77.
Malaria and dengue are the two most important vector-borne human diseases caused by mosquito vectors Anopheles stephensi and Aedes aegypti, respectively. Of the various strategies adopted for eliminating these diseases, controlling of vectors through herbs has been reckoned as one of the important measures for preventing their resurgence. Artemisia annua leaf chloroform extract when tried against larvae of A. stephensi and A. aegypti has shown a strong larvicidal activity against both of these vectors, their respective LC50 and LC90 values being 0.84 and 4.91 ppm for A. stephensi and 0.67 and 5.84 ppm for A. aegypti. The crude extract when separated through column chromatography using petroleum ether-ethyl acetate gradient (0–100 %) yielded 76 fractions which were pooled into three different active fractions A, B and C on the basis of same or nearly similar R f values. The aforesaid pooled fractions when assayed against the larvae of A. stephensi too reported a strong larvicidal activity. The respective marker compound purified from the individual fractions A, B and C, were Artemisinin, Arteannuin B and Artemisinic acid, as confirmed and characterized through FT-IR and NMR. This is our first report of strong mortality of A. annua leaf chloroform extract against vectors of two deadly diseases. This technology can be scaled up for commercial exploitation.  相似文献   
78.
CytoSorb® (CytoSorbents Corporation, USA) is a novel sorbent hemoadsorption device for cytokine removal. The aim of this study was to examine the clinical use of CytoSorb® in the management of patient with septic shock. We used this device as an adjuvant to stabilize a young patient with multi-organ failure and severe sepsis with septic shock. A 36-year-old female patient was hospitalized with the complaints of malaise, general body ache, and breathing difficulty and had a medical history of diabetes mellitus type II, hypertension, obstructive sleep apnea, hypothyroidism and morbid obesity. She was diagnosed to have septic shock with multi-organ dysfunction (MODS) and a low perfusion state. CytoSorb® hemoadsorption column was used as an attempt at blood purification. Acute physiology and chronic health evaluation score, MODS score, and sequential organ failure assessment score were measured before and after the device application. CytoSorb application as an adjuvant therapy could be considered in septic shock.  相似文献   
79.
Cherubism (OMIM : 118400) is an autosomal dominant disorder affecting mainly facial bones leading to disfigurement of face needing medical and surgical attention besides impairing the self esteem of person. At present, there is no medical cure and there is limited indication for surgery in such cases. So, correct diagnosis is of paramount importance to both treating physician and family. Here, the authors report a family with two affected members (mother and daughter) who were tested positive for a known pathogenic mutation and thus offered timely treatment and adequate genetic counseling.  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