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   1809篇
  免费   123篇
  国内免费   17篇
耳鼻咽喉   11篇
儿科学   67篇
妇产科学   47篇
基础医学   257篇
口腔科学   35篇
临床医学   151篇
内科学   317篇
皮肤病学   32篇
神经病学   234篇
特种医学   97篇
外科学   278篇
综合类   45篇
预防医学   142篇
眼科学   31篇
药学   94篇
中国医学   6篇
肿瘤学   105篇
  2023年   13篇
  2022年   12篇
  2021年   27篇
  2020年   14篇
  2019年   35篇
  2018年   32篇
  2017年   39篇
  2016年   33篇
  2015年   40篇
  2014年   38篇
  2013年   74篇
  2012年   74篇
  2011年   70篇
  2010年   45篇
  2009年   58篇
  2008年   97篇
  2007年   91篇
  2006年   98篇
  2005年   88篇
  2004年   66篇
  2003年   65篇
  2002年   57篇
  2001年   65篇
  2000年   56篇
  1999年   64篇
  1998年   49篇
  1997年   37篇
  1996年   24篇
  1995年   22篇
  1994年   21篇
  1993年   21篇
  1992年   55篇
  1991年   27篇
  1990年   29篇
  1989年   23篇
  1988年   22篇
  1987年   24篇
  1986年   18篇
  1985年   35篇
  1984年   13篇
  1983年   14篇
  1981年   10篇
  1980年   17篇
  1979年   12篇
  1978年   12篇
  1976年   11篇
  1974年   10篇
  1973年   18篇
  1971年   11篇
  1970年   13篇
排序方式: 共有1949条查询结果,搜索用时 31 毫秒
1.
The use of expanded criteria donors (ECD) has been proposed to help combat the discrepancy between organ availability and need. ECD kidneys are associated with delayed graft function (DGF) and worse long-term survival. The aim of this study is to evaluate the impact of pulsatile perfusion (PP) on DGF and graft survival in transplanted ECD kidneys. From January 2000 to December 2003, 4618 ECD kidney-alone transplants were reported to the United Network for Organ Sharing. PP was performed on 912 renal allografts. The prognostic factors of DGF were analyzed using multivariate logistic regression analysis. Risk factors for reduced allograft viability were greater in donors and recipients of PP kidneys. Three-year graft survival of ECD kidneys preserved with PP was similar to cold storage (CS) kidneys. The incidence of DGF in PP kidneys was significantly lower than CS kidneys (26% vs. 36%, p < 0.001). Despite having a greater number of risk factors for reduced graft viability, the ECD-PP kidneys had similar graft survival compared to ECD-CS kidneys. The use of PP, by decreasing the incidence of DGF, may possibly lead to lower overall costs and increased utilization of donor kidneys.  相似文献   
2.
In 17 ambulatory patients with severe intermittent dysphagia an endoscopic electrosurgical radial incision of a Schatzki ring was made with a modified straight retractable sphincterotome. The incision was successfully accomplished with immediate relief of dysphagia in all patients. Fourteen patients remain asymptomatic with a mean follow-up of 46 months after the first treatment. Three patients required a second incision and they have been asymptomatic for more than 24 months. There was one mild bleeding episode. Endoscopic electrosurgical incision of the Schatzki ring is an effective therapeutic modality in selected patients.  相似文献   
3.
We studied four patients with tumoral hyperprolactinemia and normal ovarian function before and after prolactine levels had become normal with treatment with bromocriptine (BrC), a dopamine agonist that inhibits prolactin release. Their proliferative responses to concanavalin A, pokeweed mitogen, and, to a lesser extent, phytohemagglutinin, their spontaneous and concanavalin A-induced suppression, and their production of interleukin 2 were found to be decreased and to correct partially or completely after bromocriptine treatment. The T-cell response to interleukin 2 was low in two patients in whom it increased after BrC treatment. These findings give insight on the immunomodulatory role of prolactin in vivo.  相似文献   
4.
5.
The 6-min walking distance (6MWD) test is used in clinical practice and research into patients with chronic obstructive pulmonary disease (COPD). However, little is known about natural long-term change in this parameter. The 6MWD was measured at baseline and then annually for 5 yrs in 294 patients with COPD and its annual rate of decline was determined. Forced expiratory volume in one second (FEV1) was also measured and the relationship between changes in both markers was explored. At baseline, the median 6MWD was 380 m (range 160-600 m). It declined by 19% (16 m.yr(-1)) over the 5 yrs compared with baseline in patients with American Thoracic Society/European Respiratory Society stage III COPD (FEV1 30-50% predicted) and by 26% (15 m.yr(-1)) in patients with stage IV COPD (FEV1 <30% pred). Over the 5-yr follow-up, the proportion of patients with a minimal clinically significant decline of 54 m increased with the severity of the disease. It was 24% in stage II, 45% in stage III, and 63% in stage IV disease. In contrast, the rate of decline of FEV1 was greater in patients with milder airflow obstruction and lesser in patients with lower absolute FEV1 values. In conclusion, the 6-min walking distance test provides increasingly useful information as the severity of chronic obstructive pulmonary disease increases.  相似文献   
6.
A total of 186 blood samples from 24 HIV-1 seropositive hemophiliac patients, monitored every four months for 29 months, were investigated for the presence of viral antigen in plasma. In addition, peripheral blood mononuclear cells (PBMC) were cultured for HIV-1, using normal PBMC as a target for replication. Antigenemia was detected in 51 % of the patients and from PBMC in 87.5 % of the patients. The incidence of HIV isolation in asymptomatic patients (42.8 %) was similar to that found in symptomatic patients (51.4 %). Patients with opportunistic infections had a higher incidence of lymphocytic viremia (p<0.05). Plasma viremia was closely associated (p<0.05) with low CD4+ counts and infection progression. The persistence of antigenemia was also a marker of a poor clinical course. In treated patients, plasma viremia was the marker that better correlated with the clinical course, and it did not appear during the first nine months of therapy. Zidovudine doses of >500 mg/day significantly lowered the appearance of antigenemia and lymphocytic viremia (p<0.05).  相似文献   
7.
8.
9.
Many vitreoretinal procedures are performed in offices and hospitals where cost control is important. We describe three useful devices and techniques that facilitate these procedures at minimal expense and often greater convenience. These include an accurate method for localising the pars plana without the use of callipers, an inexpensive, reliable, pressure regulated air pump for fluid-air exchange, and an easy method for intraocular injection of silicone oil through 20 gauge instrumentation without the need for expensive pumps. These procedures and techniques should prove to be useful in the treatment of vitreoretinal disease.  相似文献   
10.
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