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   5287篇
  免费   441篇
  国内免费   4篇
耳鼻咽喉   49篇
儿科学   236篇
妇产科学   109篇
基础医学   724篇
口腔科学   157篇
临床医学   559篇
内科学   980篇
皮肤病学   96篇
神经病学   315篇
特种医学   158篇
外科学   835篇
综合类   365篇
一般理论   2篇
预防医学   560篇
眼科学   49篇
药学   263篇
  1篇
中国医学   2篇
肿瘤学   272篇
  2022年   26篇
  2021年   99篇
  2020年   37篇
  2019年   74篇
  2018年   78篇
  2017年   58篇
  2016年   80篇
  2015年   96篇
  2014年   149篇
  2013年   204篇
  2012年   229篇
  2011年   239篇
  2010年   190篇
  2009年   168篇
  2008年   256篇
  2007年   239篇
  2006年   265篇
  2005年   252篇
  2004年   256篇
  2003年   217篇
  2002年   190篇
  2001年   172篇
  2000年   161篇
  1999年   179篇
  1998年   74篇
  1997年   68篇
  1996年   70篇
  1995年   69篇
  1994年   69篇
  1993年   54篇
  1992年   109篇
  1991年   117篇
  1990年   101篇
  1989年   108篇
  1988年   89篇
  1987年   70篇
  1986年   84篇
  1985年   68篇
  1984年   65篇
  1983年   48篇
  1982年   42篇
  1981年   32篇
  1980年   30篇
  1979年   45篇
  1978年   47篇
  1977年   27篇
  1976年   30篇
  1974年   35篇
  1973年   30篇
  1971年   26篇
排序方式: 共有5732条查询结果,搜索用时 15 毫秒
131.

Context

Patients triggering rapid response team (RRT) intervention are at high risk for adverse outcomes. Data on symptom burden of these patients do not currently exist, and current symptom management and communication practices of RRT clinicians are unknown.

Objectives

We sought to identify the symptom experience of RRT patients and observe how RRT clinicians communicate with patients and their families.

Methods

We conducted a prospective observational study from August to December 2015. Investigators attending RRT events measured frequencies of symptom assessment, communication, and supportive behaviors by RRT clinicians. As the rapid response event concluded, investigators measured patient-reported pain, dyspnea, and anxiety using a numeric rating scale of 0 (none) to 10 (most severe), with uncontrolled symptoms defined as numeric rating scale score of ≥4.

Results

We observed a total of 52 RRT events. RRT clinicians assessed for pain during the event in 62% of alert patients, dyspnea in 38%, and anxiety in 21%. Goals of care were discussed during 3% of events and within 24 hours in 13%. For the primary outcome measure, at the RRT event conclusion, 44% of alert patients had uncontrolled pain, 39% had uncontrolled dyspnea, and 35% had uncontrolled anxiety.

Conclusion

Hospitalized patients triggering RRT events have a high degree of uncontrolled symptoms that are infrequently assessed and treated. Although these patients experience an acute change in medical status and are at high risk for adverse outcomes, goals-of-care discussions with RRT patients or families are rarely documented in the period after the events.  相似文献   
132.
Journal of Thrombosis and Thrombolysis - Acute coronary collateralisation of an infarct-related arterial (IRA) territory may be identified during angiography for ST elevation myocardial infarction...  相似文献   
133.
A new automatic external defibrillator was tested first against a tape-recorded data base of rhythms and then during use by first-responding fire fighters in a tiered emergency system. The sensitivity for correctly classifying ventricular fibrillation and ventricular tachycardia was substantially less during clinical testing in 298 patients than would have been predicted from preclinical results: 52% of ventricular fibrillation analyses in patients were correctly classified versus 88% of episodes in the data base, and 22 versus 86%, respectively, for ventricular tachycardia (p less than 0.001). The detection algorithm was modified and evaluated further in another 322 patients. The modified detector performed substantially better than did the one that had been designed from prerecorded rhythms: with its use, 118 (94%) of 125 patients in ventricular fibrillation were counter-shocked compared with 91 (77%) of 118 similar patients with use of the initial algorithm (p less than 0.001). No inappropriate shocks were delivered. This improvement resulted in a shorter time to first shock (p less than 0.01) and more shocks being delivered for persistent or recurrent episodes of ventricular fibrillation (p less than 0.05). Of 620 patients treated with the automatic defibrillator, 243 (39%) had ventricular fibrillation; 57 (23%) of the 243 regained pulse and blood pressure before paramedics arrived, 141 (58%) were admitted to hospital and 71 (29%) were discharged.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
134.
Risk of Second Cancers in Patients with Colorectal Carcinoids   总被引:10,自引:0,他引:10  
INTRODUCTION: It is often stated that patients with colorectal carcinoid tumors have an increased risk of developing other malignancies. However, this risk has not been conclusively documented. A comprehensive evaluation is needed to more thoroughly assess the risk of second cancers in patients with colorectal carcinoids. METHODS: A search of the National Cancer Institute Surveillance, Epidemiology, and End Result database from 1973 to 1996 revealed 2,086 patients with colorectal carcinoids. This subset of patients was examined for occurrence of second cancers. The observed incidence of cancer for each site was compared with the expected incidence based on the gender-adjusted and age-adjusted cancer rates in the remaining Surveillance, Epidemiology, and End Result file. A Poisson distribution probability was used to determine the significance of these comparisons. RESULTS: Patients with colorectal carcinoids had an increased rate of cancer in the colon and rectum (P < 0.001), small bowel (P < 0.001), esophagus/stomach (P = 0.02), lung/bronchus (P < 0.001), urinary tract (P = 0.005), and prostate (P < 0.001), when compared with a control population. Most of the gastrointestinal tract cancers were synchronous cancers, whereas lesions outside the gastrointestinal tract were most commonly metachronous tumors. CONCLUSIONS: A significantly increased risk of synchronous colorectal, small-bowel, gastric, and esophageal cancers and metachronous lung, prostate, and urinary tract neoplasms is clearly demonstrated. After the diagnosis of colorectal carcinoid tumors, patients should undergo appropriate screening and surveillance for cancer at these sites.  相似文献   
135.
Acquired granular pool defect in stored platelets   总被引:1,自引:0,他引:1  
Rao  AK; Niewiarowski  S; Murphy  S 《Blood》1981,57(2):203-208
Platelets stored as concentrates (PC) for 72 h at 22 degrees C develop a functional defect. Alterations in adenine nucleotides of platelets have been shown to affect platelet function. Adenine nucleotide content of platelets was measured before and after storage and a decrease of 27.1 /+- 1.7% (mean /+- SE) in ATP and 39.1 /+- 2.6% in ADP were found in 34 PC stored with final volume of 50 ml. In 11 PC with 30 ml volume. ATP and ADP decreased by 39.4 /+- 3.2% and 49.4 /+- 2.1%, respectively. The mean ATP to ADP ratio of stored platelets was significantly higher than of fresh platelets in both groups, suggesting a relatively greater decrease in granular than metabolic pool nucleotides. Levels of low affinity platelet factor 4 measured by radioimmunoassay in plasma from 0.86 /+- 0.08 microgram/ml in the fresh PC to 8.59 /+- 0.39 microgram/ml in stored PC, indicating a concomitant alpha-granular secretion. Labeling of metabolic pool with 14C-adenine revealed a mean decrease in the adenylate energy charge of 2.0 /+- 0.4% in 12 of 16 stored PC, with a lower ATP and higher hypoxanthine labeling in stored as compared to fresh platelets. These observations suggest that stored platelets develop an acquired defect in both dense and alpha granules and in their ability to maintain ATP homeostasis.  相似文献   
136.
137.
The primary identified function of complement receptor 1 (CR1/CD35) on primate erythrocytes is to bind complement-tagged inflammatory particles including microbes and immune complexes. When erythrocytes circulate through liver and spleen, sinusoidal phagocytes remove CR1-adherent particles and erythrocytes return to the circulation. This process of immune adherence clearance is important for host defense and prevention of autoimmunity. CR1 was previously described as clustered in the human erythrocyte membrane, which was thought to be necessary for binding complement-opsonized particles. In contrast, we demonstrate that on erythrocytes CR1 is not clustered, but dispersed, and able to bind complement-tagged particles. When fresh erythrocytes are solubilized by nonionic detergent, CR1 partitions to the cytoskeleton fraction. Using a PDZ-peptide array, CR1's cytoplasmic tail, which contains 2 PDZ-motifs, binds PDZ domains 2, 3, and 5 of Fas-associated phosphatase 1 (FAP-1), a scaffolding protein. We show that FAP-1, not previously recognized as an erythroid protein, is expressed on circulating erythrocytes. CR1 and FAP-1 coimmunoprecipitate, which confirms their molecular association. Disperse CR1 on erythrocytes may be advantageous for capturing immune-complexes, while ligation-induced CR1 clustering may prevent ingestion of the erythrocyte during the immune-complex transfer to the macrophages by keeping the opsonic stimulus localized thus preventing phagocyosis.  相似文献   
138.
A prehospital computer-interpreted electrocardiogram (ECG) was obtained in 1,189 patients with chest pain of suspected cardiac origin during an ongoing trial of prehospital thrombolytic therapy in acute myocardial infarction. Electrocardiograms were performed by paramedics 1.5 +/- 1.2 h after the onset of symptoms. Of 391 patients with evidence of acute myocardial infarction, 202 (52%) were identified as having ST segment elevation (acute injury) by the computer-interpreted ECG compared with 259 (66%) by an electrocardiographer (p less than 0.001). Of 798 patients with chest pain but no infarction, 785 (98%) were appropriately excluded by computer compared with 757 (95%) by an electrocardiographer (p less than 0.001). The positive predictive value of the computer- and physician-interpreted ECG was, respectively, 94% and 86% and the negative predictive value was 81% and 85%. Prehospital screening of possible candidates for thrombolytic therapy with the aid of a computerized ECG is feasible, highly specific and with further enhancement can speed the care of all patients with acute myocardial infarction.  相似文献   
139.
Between 1976 and 1981 Haemophilus influenzae was identified in 16 women with postpartum bacteremia and 36 neonates with bacteremia or meningitis. H. influenzae was also recovered from neonatal or genital cultures of 50 additional patients. By counter-immunoelectrophoresis 17% of neonatal isolates from blood or cerebrospinal fluid (CSF) were type b. All remaining strains (94% overall) were nontypable (NT). Of the NT blood or CSF isolates, 38% belonged to biotype 4. Of all the NT biotype 4 isolates referred to the Centers for Disease Control during the study, 82% were of genital, neonatal, or maternal origin, a finding that suggests that this isolate is a genital biotype. Clinical disease was similar to that observed in patients infected with group B Streptococcus except for the infrequent (11%) occurrence of meningitis. Maternal bacteremia resulted in mild febrile illness, while neonatal bacteremia was associated with a high incidence of shock, respiratory distress (50%), and death (30%). H. influenzae bacteremia in these two patient groups was rare in Houston before 1976, but since then it has been responsible for 2.5% of cases of significant bacteremia. NT H. influenzae should be recognized as a definite neonatal, maternal, and genital pathogen.  相似文献   
140.
Ventricular fibrillation causes sudden death in Southeast Asian immigrants   总被引:4,自引:0,他引:4  
Young, male, Southeast Asian immigrants living in the United States have a high incidence of unexplained, sudden, nocturnal death. We report the cases of three patients, two Laotians and one Filipino, who were resuscitated and subsequently studied extensively. Each patient was having ventricular fibrillation when first examined by paramedics outside the hospital, and episodes of fibrillation recurred in the early hospital course. Clinical evaluation found no significant coronary atherosclerosis or structural cardiac disease. One patient is asymptomatic after 2 years; the second patient died suddenly at 4 months; and the third is asymptomatic but had inducible ventricular tachycardia on electrophysiologic testing 6 months after resuscitation. The mechanism of sudden death in young Southeast Asian men appears to be ventricular fibrillation. The cause of the arrhythmia is unclear, although in our patients the arrhythmia was not an isolated event; underlying predispositions to further cardiac arrest persisted.  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