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   3135篇
  免费   177篇
  国内免费   18篇
耳鼻咽喉   24篇
儿科学   107篇
妇产科学   33篇
基础医学   261篇
口腔科学   100篇
临床医学   230篇
内科学   777篇
皮肤病学   43篇
神经病学   150篇
特种医学   150篇
外科学   662篇
综合类   76篇
一般理论   1篇
预防医学   256篇
眼科学   56篇
药学   208篇
中国医学   16篇
肿瘤学   180篇
  2023年   29篇
  2022年   12篇
  2021年   106篇
  2020年   59篇
  2019年   77篇
  2018年   101篇
  2017年   59篇
  2016年   67篇
  2015年   59篇
  2014年   132篇
  2013年   151篇
  2012年   182篇
  2011年   230篇
  2010年   134篇
  2009年   131篇
  2008年   162篇
  2007年   173篇
  2006年   165篇
  2005年   163篇
  2004年   140篇
  2003年   153篇
  2002年   150篇
  2001年   64篇
  2000年   68篇
  1999年   50篇
  1998年   20篇
  1997年   10篇
  1996年   19篇
  1995年   18篇
  1994年   17篇
  1993年   14篇
  1992年   33篇
  1991年   36篇
  1990年   35篇
  1989年   27篇
  1988年   30篇
  1987年   35篇
  1986年   26篇
  1985年   27篇
  1984年   14篇
  1983年   10篇
  1981年   8篇
  1979年   15篇
  1978年   13篇
  1973年   11篇
  1970年   9篇
  1969年   13篇
  1968年   8篇
  1967年   7篇
  1966年   9篇
排序方式: 共有3330条查询结果,搜索用时 31 毫秒
1.
The expression of ras oncogene in normal and pathological liver disease   总被引:1,自引:0,他引:1  
Activation of the ras oncogene is associated with overproduction of the normal gene product (p21). Ninety one paraffin-embedded specimens were used to map the distribution of the normal form of p21 in normal, inflamed, cirrhotic and carcinomatous liver parenchyma. Monoclonal antibodies (Mo-RAP) were raised against the normal form of the ras-oncogene product and histological sections were stained by the peroxidase-antiperoxidase technique. Normal, inflamed and cirrhotic liver showed either minimal or moderate cytoplasmic staining. By contrast primary (n = 13) and secondary (n = 41) liver carcinomas exhibited intense staining. The differential pattern observed in p21 distribution could have useful clinical applications.  相似文献   
2.
3.
4.
PURPOSE: To report the use of regional anesthesia and iv nitroglycerin to provide anesthesia and uterine relaxation for three Cesarean deliveries (CD) involving ex utero intrapartum treatment (EXIT) of potentially life-threatening airway obstruction in the newborn. CLINICAL FEATURES: Case 1--a 36-yr-old woman at 38 weeks' gestation was scheduled for an elective CD for fetal skeletal dysplasia and micrognathia. Case 2--a 34-yr-old woman at 35 weeks gestation had a fetal ultrasound revealing fixed neck flexion and micrognathia consistent with fetal arthrogryposis. Case 3--a 27-yr-old woman presented at 38 weeks gestation for CD for severe fetal micrognathia, with mandibular growth below the fifth percentile. For each case, a combined spinal epidural anesthetic was performed with 0.75% bupivacaine, fentanyl and morphine intrathecally followed by placement of a multiorifice epidural catheter. Prior to uterine incision patients received a loading dose followed by an iv infusion of nitroglycerin. Uterine relaxation was sufficient in all cases for delivery of the fetus, and allowed for evaluation by direct laryngoscopy and intubation while maintaining fetal-placental circulation. The surgical procedures were completed without incident. CONCLUSIONS: Anesthesia and uterine relaxation for CD and EXIT procedures can be safely provided with regional anesthesia and iv nitroglycerin.  相似文献   
5.
Over a 15-year period we observed seven children (four girls, three boys) who presented within the first months of life with severe renal failure and acidosis, associated with hypertension in five patients and polyuria in four. In addition, one patient had a severe cholestatic liver disease. In two families, a similarly affected sibling had died previously. Four patients were referred with the clinical diagnosis of polycystic kidney disease because of moderate enlargement of kidneys, but renal imaging (intravenous pyelography and ultrasonography) did not confirm this diagnosis. A renal biopsy, performed in all patients, showed similar features characterized by a diffuse chronic tubulo-interstitial nephritis (TIN) and particularly by the presence of microcystic dilatation of proximal tubules and Bowman's space. Liver pathology was normal in two patients, including one with hepatomegaly. However, in the patient with cholestasis there was inflammatory portal fibrosis with mild duct proliferation. Progression of the renal disease was extremely rapid and all patients reached end-stage renal failure (ESRF) before the age of 2 years (11–22 months). Two children had successful renal transplants. Although this chronic TIN shares some features with nephronophthisis, we suggest that it represents a distinct entity both on clinical and morphological grounds. The specific clinical features of this disease are its early onset and rapid progression to ESRF. Pathologically, it differs from nephronophthisis by the absence of medullary cysts and thickened tubular basement membranes and by the presence of cortical microcysts.  相似文献   
6.
Gall bladder hydatid cyst is a rare entity. Concurrent occurrence of gall blader hydatid cysts along with liver cysts, especially with the biliary channels clear of cysts, is very rare. We report a 27-year-old man with a gall bladder hydatid cyst that was diagnosed only after opening the resected specimen of the gall bladder.  相似文献   
7.
Treatment defaulting is one of the major causes of the failure of TB control programs. In Bethania Hospital. Sialkot, defaulting rates are high: 72% for the standard 12 months course and 56% for the 8 months course. Attrition is especially important in the first weeks of treatment: < 70% of the patients start the 10th week of treatment. A focus group discussion study has been carried out to gain a better understanding of the impact of social stigmatization, treatment cost and pregnancy on defaulting. The study population consisted of 3 male and 3 female groups each with 8 hospitalized TB patients. The study shows that TB is perceived as a very dangerous, infectious and incurable disease. This perception has many social consequences: stigmatization and social isolation of TB patients and their families; diminished marriage prospects for young TB patients, and even for their family members; TB in one of the partners may lead to divorce. Due to fear patients often deny the diagnosis and reject the treatment. While both male and female TB patients face many social and economical problems, female patients are more affected. Divorce and broken engagements seem to occur more often in female patients. Females are usually economically dependent on their husbands and family in law, and need their cooperation to avail of treatment. The belief that pregnancy enhances the risk for relapse decreases their marriage prospects. Pregnancy is also a reason for stopping TB treatment as both are considered as incompatible. The findings of this study reveal the urgent need for a health education campaign to convince the general population that tuberculosis is curable. All health care providers should act as destigmatizers.  相似文献   
8.
Over the last five years a policy of systematic screening for small hepatocellular carcinomas (HCC) in patients at risk has led to an increasing number of resections in patients with cirrhosis. Remarkable progress in the surgery of HCC in cirrhosis has been accomplished through: (a) a better understanding of the surgical anatomy of the liver, (b) the definition of new types of liver resection aimed at reducing the amount of parenchyma removed while still being oncologically satisfactory, (c) the reduction of intraoperative blood loss by various techniques of clamping afferent and efferent vessels, (d) the systematic use of intraoperative ultrasonography, and (e) the prevention of postoperative variceal bleeding and the formation of ascites. Results of resection of small HCC in cirrhosis have been quite impressive in Japanese series, with a low operative mortality and above 50% three-year survivals. Results in the West have been somewhat less good. Differences in the pathology of these tumours and particularly in the rate of encapsulation could account for these differences. Clearly, surgical resection has become an established treatment for small HCC in cirrhosis. More information is needed on the results of surgery in operated patients and this should be compared with the natural history of small HCC in cirrhosis in order to better define the patients who will most benefit from these operations and which tests performed at which intervals, are most reliable in screening patients at risk.  相似文献   
9.
Ulcerative colitis (UC) and Crohn's disease (CD) are heterogeneous disorders characterized by chronic intestinal inflammation. Genetic predisposition is a major risk factor in both diseases. The CARD15 (NOD2) gene has been implied as a candidate gene in the pathogenesis CD. Our aim was to delineate the frequency of three missense and one frameshift variant of CARD15 in Israeli Jewish CD and UC patients. DNA was extracted from blood samples from 238 unrelated inflammatory bowel disease (IBD) patients, 68 with UC and 170 with CD. The DNA was genotyped for two missense mutations, R675W and G881R, and one frameshift mutation, 980FS981X. Mutations in CARD15 were observed with significantly greater frequency in CD patients (46/170, 27%) than in UC patients (7/68, 10%) (P = 0.005). Homozygous and compound heterozygous carriers were restricted to seven (4%) patients with CD as compared to none of the UC patients (P = 0.01). Similar rates in Ashkenazi and non-Ashkenazi Jewish patients were observed. Age-of-onset of disease was lower in Ashkenazi mutation carriers as compared to non-carriers of Ashkenazi origin (18.7 +/- 8.6 years vs. 25.8 +/- 13.4 years, respectively, P = 0.03). No other phenotypic characteristics could distinguish mutation carriers from non-carriers. We conclude that germline mutations in the CARD15 gene are more frequently found in CD than UC patients and appear to predict an earlier age-of-onset in Ashkenazi Jewish patients. No association could be demonstrated between CARD15 mutations and specific disease course or behavior.  相似文献   
10.
Sjogren's syndrome (SS) describes xeropthalmia and xerostomia due to lymphocytic infiltrates of lacrimal and salivary glands. SS may occur alone (primary SS) or in association with several other autoimmune diseases (secondary SS). The clinical features involve a wide variety of organs, including skin, eyes, oral cavity and salivary glands, and systems, including nervous, musculoskeletal, genitourinary and vascular. Sicca symptoms can be found in a number of other disorders including rheumatoid arthritis, systemic lupus erythematosus, scleroderma, primary biliary cirrhosis, and other rheumatic disorders.  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