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   7375篇
  免费   462篇
  国内免费   77篇
耳鼻咽喉   84篇
儿科学   335篇
妇产科学   198篇
基础医学   1007篇
口腔科学   225篇
临床医学   711篇
内科学   1651篇
皮肤病学   135篇
神经病学   795篇
特种医学   629篇
外国民族医学   1篇
外科学   843篇
综合类   119篇
一般理论   3篇
预防医学   371篇
眼科学   90篇
药学   269篇
  2篇
中国医学   1篇
肿瘤学   445篇
  2021年   86篇
  2020年   52篇
  2019年   82篇
  2018年   123篇
  2017年   94篇
  2016年   114篇
  2015年   127篇
  2014年   167篇
  2013年   226篇
  2012年   253篇
  2011年   252篇
  2010年   242篇
  2009年   199篇
  2008年   259篇
  2007年   289篇
  2006年   234篇
  2005年   263篇
  2004年   190篇
  2003年   209篇
  2002年   206篇
  2001年   184篇
  2000年   201篇
  1999年   172篇
  1998年   185篇
  1997年   201篇
  1996年   185篇
  1995年   147篇
  1994年   142篇
  1993年   139篇
  1992年   160篇
  1991年   175篇
  1990年   150篇
  1989年   172篇
  1988年   130篇
  1987年   147篇
  1986年   140篇
  1985年   135篇
  1984年   93篇
  1983年   76篇
  1982年   85篇
  1981年   76篇
  1980年   62篇
  1979年   66篇
  1978年   55篇
  1977年   74篇
  1976年   61篇
  1975年   79篇
  1974年   44篇
  1973年   49篇
  1972年   49篇
排序方式: 共有7914条查询结果,搜索用时 62 毫秒
101.
OBJECTIVE: To test the hypothesis that a supply of frozen red blood cells and a system for processing pyrogen-free crystalloid solution would meet the needs of an echelon 3 medical treatment facility in the U.S. military, caring for casualties during the initial phase of a military medical operation. DATA SOURCES: Blood requirements for potential combat casualties were estimated from transfusion data on: (1) patients admitted to Boston City Hospital following trauma, utilizing a computerized data base, (2) patients admitted to the Naval Support Hospital-Da Nang during the Vietnam War, from 1966 to 1970, from published and unpublished material, and (3) casualties estimated by Department of Defense expert panels for specific conflicts. The procedure for processing frozen red blood cells was evaluated at the Naval Blood Research Laboratory. Estimates of wounded in action were provided by the Department of Defense. DATA SYNTHESIS: Computer modeling using standard spreadsheet software on a personal computer. CONCLUSIONS: Under military conditions, a frozen red blood cell bank and a system for processing pyrogen-free resuscitative fluid could be used to prepare 96 units of red cells and 960 1 of crystalloid solution per day. This would be adequate to treat approximately 180 casualties, the number projected for a 5-day battle with heavy casualties (6 wounded in action/1,000 soldiers/day). It was concluded that a frozen blood bank system and system for processing pyrogen-free resuscitative fluid could successfully meet the needs of an echelon 3 medical facility in the initial phase of a military medical operation.  相似文献   
102.
103.
104.
High-dose (HD) cytosine arabinoside (ARA-C) is more effective treatment than conventional-dose ARA-C regimens for patients with relapsed acute nonlymphocytic leukemia (ANLL). We report here that HD ARA-C given during the first remission of ANLL has resulted in long remission durations and a high proportion of patients who survive more than three years free of disease. From August 1979 to September 1983, 36 adult patients with ANLL in first remission received one to three courses of HD ARA-C (3 g/m2 by one-hour infusion every 12 hours for 12 doses on days 1 through 6) alone or with daunorubicin (30 mg/m2 for two or three doses on days 7 through 9). Three patients died of sepsis or hemorrhage during consolidation, and 14 patients have relapsed from five to 48 months after diagnosis. The remaining 19 patients are in continued complete remission (CCR) from 11 to 62 months. Denoting all deaths in remission as relapse, the actuarial probability of CCR is 42% at 62 months, with an apparent plateau in the survival curve. Of the first 22 patients treated, ten remain in CCR from 37 to 62 months with no therapy for at least three years. Due to its heightened anti-leukemic activity, HD ARA-C allows brief but effective consolidation of ANLL in first remission, with long-term disease-free survival comparable to other approaches.  相似文献   
105.
In 22 patients with malignancies, treated with high-dose chemoradiotherapy and autologous bone marrow transplantation (BMT), peripheral blood T cell subsets and functions were studied. In ten cytomegalovirus (CMV)-negative patients, CD4+ and CD8+ T cells (representing T cells of the helper/inducer phenotype and T cells of the suppressor/cytotoxic phenotype, respectively), recovered slowly and simultaneously. In 12 CMV-positive patients, however, CD8+ T cells recovered more rapidly than CD4+ T cells and rose to increased counts. No T cells with an immature phenotype (CD1+, OKT6+) were observed. Lymphocyte stimulation by herpes simplex virus infected fibroblasts (and by CMV-infected fibroblasts in CMV-positive patients) in contrast remained high and even increased after BMT in both groups. These data indicate that T cell recovery after autologous BMT is mainly due to proliferation of mature T cells present in the BM graft and not to generation of new T cells from T cell precursors.  相似文献   
106.
107.

Background

To evaluate the haemodynamic changes induced by flow diversion treatment in cerebral aneurysms, resulting in thrombosis or persisting aneurysm patency over time.

Method

Eight patients with aneurysms at the para-ophthalmic segment of the internal carotid artery were treated by flow diversion only. The clinical follow-up ranged between 6?days and 12?months. Computational fluid dynamics (CFD) analysis of pre- and post-treatment conditions was performed in all cases. True geometric models of the flow diverter were created and placed over the neck of the aneurysms by using a virtual stent-deployment technique, and the device was simulated as a true physical barrier. Pre- and post-treatment haemodynamics were compared, including mean and maximal velocities, wall-shear stress (WSS) and intra-aneurysmal flow patterns. The CFD study results were then correlated to angiographic follow-up studies.

Results

Mean intra-aneurysmal flow velocities and WSS were significantly reduced in all aneurysms. Changes in flow patterns were recorded in only one case. Seven of eight aneurysms showed complete occlusion during the follow-up. One aneurysm remaining patent after 1?year showed no change in flow patterns. One aneurysm rupturing 5?days after treatment showed also no change in flow pattern, and no change in the maximal inflow velocity.

Conclusions

Relative flow velocity and WSS reduction in and of itself may result in aneurysm thrombosis in the majority of cases. Flow reductions under aneurysm–specific thresholds may, however, be the reason why some aneurysms remain completely or partially patent after flow diversion.  相似文献   
108.

Purpose

We compared renal function outcomes among patients in the surveillance and intervention arms of the DISSRM registry.

Materials and methods

Patients were grouped into chronic kidney disease stages by estimated glomerular filtration rate range. Cases were considered up staged if a more advanced chronic kidney disease stage was entered during followup. Chronic kidney disease up staging-free survival was compared among groups using Kaplan-Meier analysis and paired comparisons log rank tests. Multivariate Cox regression identified independent predictors of chronic kidney disease up staging-free survival.

Results

A total of 162 patients met the study inclusion criteria, with 68 in the surveillance arm, 65 undergoing partial nephrectomy, 15 undergoing radical nephrectomy, and 14 undergoing cryoablation. Median tumor size was 2.2 cm. Mean estimated glomerular filtration rate change was significantly larger for radical nephrectomy vs. surveillance (?9.2 vs. ?0.5 ml/min/1.73 m2) and for radical vs. partial nephrectomy (?9.2 vs. ?1.9 ml/min/1.73 m2) (P = 0.001). No other groups differed significantly. On Kaplan-Meier analysis, patients undergoing radical nephrectomy had significantly worse chronic kidney disease up staging-free survival vs. those treated with partial nephrectomy (P = 0.029), surveillance (P = 0.007), and cryoablation (P = 0.019). No other groups differed significantly. On multivariate analysis, radical nephrectomy independently predicted poor chronic kidney disease up staging-free survival (odds ratio vs. surveillance 30.6, P = 0.001). Neither partial nephrectomy (P = 0.985) nor cryoablation (P = 0.976) predicted poor chronic kidney disease up staging-free survival relative to surveillance.

Conclusions

Patients in the surveillance arm had superior estimated glomerular filtration rate preservation compared to those in the radical nephrectomy but not the partial nephrectomy arm. In certain patients with small renal masses, surveillance and partial nephrectomy may offer comparable renal functional outcomes. This could be partly attributable to a modest estimated glomerular filtration rate decrease associated with surveillance itself. A thorough understanding of the renal functional impacts of treatment modalities is critical in the management of small renal masses.  相似文献   
109.
We assessed the impact of antiviral preventive strategies on the incidence of herpes simplex virus (HSV) and varicella‐zoster virus (VZV) infections in a nationwide cohort of transplant recipients. Risk factors for the development of HSV or VZV infection were assessed by Cox proportional hazards regression. We included 2781 patients (56% kidney, 20% liver, 10% lung, 7.3% heart, 6.7% others). Overall, 1264 (45%) patients received antiviral prophylaxis (ganciclovir or valganciclovir, n = 1145; acyclovir or valacyclovir, n = 138). Incidence of HSV and VZV infections was 28.9 and 12.1 cases, respectively, per 1000 person‐years. Incidence of HSV and VZV infections at 1 year after transplant was 4.6% (95% confidence interval [CI] 3.5–5.8) in patients receiving antiviral prophylaxis versus 12.3% (95% CI 10.7–14) in patients without prophylaxis; this was observed particularly for HSV infections (3% [95% CI 2.2–4] versus 9.8% [95% CI 8.4–11.4], respectively). A lower rate of HSV and VZV infections was also seen in donor or recipient cytomegalovirus‐positive patients receiving ganciclovir or valganciclovir prophylaxis compared with a preemptive approach. Female sex (hazard ratio [HR] 1.663, p = 0.001), HSV seropositivity (HR 5.198, p < 0.001), previous episodes of rejection (HR 1.95, p = 0.004), and use of a preemptive approach (HR 2.841, p = 0.017) were significantly associated with a higher risk of HSV infection. Although HSV and VZV infections were common after transplantation, antiviral prophylaxis significantly reduced symptomatic HSV infections.  相似文献   
110.
40例鼓室成形术临床结果分析   总被引:1,自引:0,他引:1  
目的研究Ⅲ、Ⅳ型鼓室成形术后听力改善的情况.方法回顾性总结美国匹兹堡大学医学中心眼耳研究所从1992-2000年随访的40例鼓室成形术病人,其中Ⅲ型和Ⅳ型各20例.Ⅲ型中男6例,女14例.平均年龄43.55岁(范围11-79岁).Ⅳ型中男3例,女17例,平均年龄45.11岁(范围12-74岁).Ⅲ型中9例有胆脂瘤.Ⅳ型中7例有胆脂瘤.20例Ⅲ型病人中4例采用金伯格人工听骨,16例采用自体-异体砧骨.20例Ⅳ型病人中10例采用金伯格人工听骨,4例采用理查德人工听骨,6例采用鲁森斯基人工听骨.所有的病人都行Ⅰ期听骨链重建.结果所有的病人在术后3月、6月、12月随访.Ⅲ型术后气骨导差距≤20dB者15例,占75%.Ⅳ型术后气骨导差距≤20dB者12例,占60%.结论Ⅲ、Ⅳ型鼓室成形术都能得到较好的听力改善.  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