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   1397篇
  免费   91篇
  国内免费   17篇
耳鼻咽喉   30篇
儿科学   57篇
妇产科学   9篇
基础医学   163篇
口腔科学   88篇
临床医学   150篇
内科学   225篇
皮肤病学   16篇
神经病学   65篇
特种医学   135篇
外科学   234篇
综合类   113篇
一般理论   1篇
预防医学   87篇
眼科学   7篇
药学   53篇
中国医学   1篇
肿瘤学   71篇
  2021年   20篇
  2020年   10篇
  2019年   15篇
  2018年   14篇
  2017年   16篇
  2016年   16篇
  2015年   30篇
  2014年   49篇
  2013年   47篇
  2012年   58篇
  2011年   43篇
  2010年   42篇
  2009年   47篇
  2008年   62篇
  2007年   51篇
  2006年   28篇
  2005年   35篇
  2004年   37篇
  2003年   44篇
  2002年   25篇
  2001年   34篇
  2000年   27篇
  1999年   42篇
  1998年   55篇
  1997年   52篇
  1996年   38篇
  1995年   24篇
  1994年   33篇
  1993年   28篇
  1992年   21篇
  1991年   31篇
  1990年   28篇
  1989年   25篇
  1988年   29篇
  1987年   43篇
  1986年   29篇
  1985年   31篇
  1984年   18篇
  1983年   21篇
  1982年   18篇
  1981年   11篇
  1979年   13篇
  1978年   13篇
  1977年   12篇
  1976年   19篇
  1974年   11篇
  1973年   10篇
  1972年   15篇
  1970年   9篇
  1966年   10篇
排序方式: 共有1505条查询结果,搜索用时 15 毫秒
51.
A patient survived a stab wound of the heart, and an aneurysm of the left anterior descending coronary artery developed with a fistulous communication into the left ventricle and a postinfarction ventricular aneurysm. All lesions were successfully repaired by surgery 4 years later. Preoperatively the patient suffered from angina pectoris presumably due to a coronary arterial “steal syndrome” and recurrent myocardial infarction presumably due to coronary embolism from thrombi formed within the coronary aneurysm. The combination of a coronary arterial aneurysm and a coronary arterial-left ventricular fistula produced a diastolic murmur that disappeared after surgery.  相似文献   
52.
Thymuses from female (New Zealand black x New Zealand white)F1 [( NZB x NZW]F1), New Zealand black, and New Zealand white mice of different ages were examined by immunohistochemical and flow cytometric analysis. Two-and-a-half-month-old (NZB x NZW)F1 mice showed infiltration of the thymus with B cells, and by 6-8 months of age, showed a disruption of the entire medullary area. More than 80% of the thymic B cells had the phenotypic characteristics of conventional B cells (IgM+, IgD+, Ly-1-). Total lymphoid irradiation induced a marked depletion of medullary B cells and a restoration of the thymic architecture.  相似文献   
53.
Summary We occluded the left anterior descending coronary artery of anesthetized, open-chest dogs, for 1 or 2 h. Some hearts were reperfused for 1 h after 1 h of ischemia. We isolated mitochondria from the central ischemic zone (CIZ) and a surrounding nonischemic zone (NIZ) of the left ventricle, and assayed H2O2 production using a horseradish peroxidase-dual wavelength spectrophotometric technique. Mitochondria, studied in the absence of exogenous respiratory chain inhibitors, generated H2O2 during State 4 respiration with succinate as the substrate. NIZ mitochondria in all groups produced ca. 1.5 nmols H2O2/min/mg protein (no significant differences between groups). The State 4 O2 consumption rates of NIZ mitochondria from hearts subjected to 1 h ischemia plus reperfusion, or 2 h of ischemia (ca. 30 nmols/min/mg) were significantly higher than that of NIZ mitochondria of hearts subjected to only 1 h of ischemia (23 nmols/min/mg). Thus, the ratio between H2O2 produced and State 4 O2 consumption fell from 6.5% to 5%. Mitochondria from all CIZ samples had State 4 O2 consumption rates that were not different from corresponding NIZ values. However CIZ mitochondria of hearts subjected to 1 h ischemia without reperfusion produced less H2O2 (1.1±0.1 nmols/min/mg), and had a slightly reduced H2O2/O2 ratio (4.4±0.7%), compared with their NIZ samples (1.5±0.1 nmols/min/mg; 5.3%). Reperfusion after 1 h of ischemia abolished these regional differences. The CIZ mitochondria from hearts subjected to 2 h ischemia produced only 0.75±0.22 nmols H2O2/min/mg (2.5% of State 4 O2 consumption). These values were 50% of corresponding NIZ values, and were significantly less than for any other group or tissue region. If similar phenomena occur in conscious animals subjected to incomplete regional ischemia, especially of relatively brief duration or if accompanied by reduced intracellular defenses against oxidants such as H2O2, they suggest that mitochondria persist as H2O2 sources and so may contribute to the oxidant load and myocardial dysfunction.Supported by grants from the National Institutes of Health (HL-29499) and from the American Heart Association of Michigan  相似文献   
54.
55.
Introduction Excision followed by RFA (eRFA) may allow improved cosmesis while ensuring negative margins in patients with breast cancer. This technique utilizes heat to create an additional tumor-free zone around the lumpectomy cavity. We hypothesized that eRFA will decrease the need for re-excision of inadequate margins.Methods Between July 2002 and January 2005, we conducted a multiphase trial of RFA of prophylactic mastectomy specimens and of women desiring lumpectomy. In both models, a lumpectomy was performed, the RFA probe was deployed 1 cm circumferentially into the walls of the lumpectomy cavity and maintained at 100°C for 15 min. Whole mount slides were used to measure the zone of ablation for ex vivo specimens. Hematoxylin and eosin staining of in vivo lumpectomy margins <3 mm was considered inadequate.Results Nineteen prophylactic mastectomy ablations revealed a consistent perimeter of ablation. Forty-one patients (mean age 63 ± 14 years) had an average tumor size of 1.6 ± 1.5 cm underwent in vivo eRFA, and 25% had inadequate margins: one focally positive, one <2 mm, eight <1 mm and one grossly positive. Only the grossly positive margin was re-excised. Overall complication rate of in vivo ablations was 7.5%. Twenty-four of 41 patients did not have post-eRFA XRT. No in-site local recurrences have occurred during a median follow-up of 24 months (12–45 months). Two patients have occurred elsewhere.Conclusions The ex vivo ablation model reliably created a 5–10 mm perimeter of ablation. In vivo, this zone reduced the need for re-excision for inadequate margins by 91% (10/11). Short-term follow-up suggests that eRFA could reduce re-excision surgery and local recurrence.  相似文献   
56.
57.
OBJECTIVE: To provide preliminary estimates of the effectiveness of cognitive-behavioral therapy (CBT) in treating pediatric obsessive-compulsive disorder (OCD) of the pediatric autoimmune neuropsychiatric disorders associated with streptococcus (PANDAS) subtype. METHOD: Seven children with OCD of the PANDAS subtype (range 9-13 years) were treated in a 3-week intensive CBT program conducted at a university clinic. Six of seven children were taking selective serotonin reuptake inhibitor medication(s) upon presentation. Assessments were conducted at four time points: baseline, pretreatment approximately 4 weeks later, posttreatment, and 3-month follow-up. Raters were blind to the nature of the study treatment. RESULTS: Six of seven participants were classified as treatment responders (much or very much improved) at posttreatment, and three of six remained responders at follow-up. Clinician severity ratings, as measured by the Children's Yale-Brown Obsessive-Compulsive Scale and Anxiety Disorder Interview Schedule for DSM-IV Child Interview Schedule-Parent version, decreased significantly following intervention, with effect sizes of 3.38 and 2.29, respectively. Self-reported general anxiety and depression symptoms were not significantly reduced. CONCLUSIONS: This study provides preliminary support for CBT in treating the PANDAS subtype of pediatric OCD. This approach is also considered a safe and minimally invasive treatment approach.  相似文献   
58.
59.
In this study psychometric properties of seven self-report measures of posttraumatic stress disorder (PTSD) were compared. The seven scales evaluated were the Davidson Trauma Scale (DTS), the PTSD Checklist (PCL), the Posttraumatic Stress Diagnostic Scale (PDS), the Civilian Mississippi Scale (CMS), the Impact of Event Scale-Revised (IES-R), the Penn Inventory for Posttraumatic Stress Disorder (Penn), and the PK scale of the MMPI-2 (PK). Participants were 239 (79 male and 160 female) trauma-exposed undergraduates. All seven measures exhibited good test-retest reliability and internal consistency. The PDS, PCL and DTS demonstrated the best convergent validity; the IES-R, PDS, and PCL demonstrated the best discriminant validity; and the PDS, PCL, and IES-R demonstrated the best diagnostic utility. Overall, results most strongly support the use of the PDS and the PCL for the assessment of PTSD in this population.  相似文献   
60.
Nonsurgical repositioning of central venous catheters   总被引:2,自引:0,他引:2  
Lois  JF; Gomes  AS; Pusey  E 《Radiology》1987,165(2):329-333
Long-term central venous catheters are placed for total parenteral nutrition and/or chemotherapy. These catheters are placed surgically and fixed to the subcutaneous tissues. Complications include infection, venous thrombosis, and mechanical problems. The authors developed a method to percutaneously reposition displaced central venous catheters. The procedure is performed with fluoroscopy and modified angiographic techniques. Fifteen patients underwent a total of 17 procedures. The initial success rate was 76%; the final success rate was 88%. Many central venous catheters can be salvaged with this low-morbidity procedure, which negates the need for surgical intervention.  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