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   1448篇
  免费   115篇
  国内免费   53篇
耳鼻咽喉   7篇
儿科学   77篇
妇产科学   39篇
基础医学   125篇
口腔科学   37篇
临床医学   205篇
内科学   372篇
皮肤病学   30篇
神经病学   130篇
特种医学   158篇
外国民族医学   1篇
外科学   196篇
综合类   27篇
预防医学   66篇
眼科学   16篇
药学   68篇
  1篇
中国医学   9篇
肿瘤学   52篇
  2021年   8篇
  2020年   10篇
  2019年   8篇
  2018年   26篇
  2017年   24篇
  2016年   27篇
  2015年   31篇
  2014年   44篇
  2013年   60篇
  2012年   38篇
  2011年   45篇
  2010年   55篇
  2009年   71篇
  2008年   42篇
  2007年   59篇
  2006年   46篇
  2005年   50篇
  2004年   31篇
  2003年   39篇
  2002年   25篇
  2001年   38篇
  2000年   35篇
  1999年   39篇
  1998年   77篇
  1997年   87篇
  1996年   59篇
  1995年   56篇
  1994年   41篇
  1993年   44篇
  1992年   25篇
  1991年   20篇
  1990年   28篇
  1989年   39篇
  1988年   35篇
  1987年   45篇
  1986年   30篇
  1985年   28篇
  1984年   17篇
  1983年   20篇
  1982年   14篇
  1981年   11篇
  1980年   10篇
  1979年   7篇
  1978年   9篇
  1977年   13篇
  1976年   8篇
  1975年   5篇
  1974年   6篇
  1973年   7篇
  1972年   9篇
排序方式: 共有1616条查询结果,搜索用时 0 毫秒
31.
AIM OF THE STUDY: To evaluate the results of laparoscopic splenectomy for hematologic diseases by a multicenter retrospective study. PATIENTS AND METHODS: Between 1991 and 1998, 275 patients (mean age: 40.4 years [18-93]) underwent splenectomy for idiopathic thrombocytopenic purpura (ITP) (n = 209, 76%), for hemolytic anemia (HA) (n = 37) including hereditary spherocytosis (n = 13) and auto-immune anemia (n = 24), lymphoma (n = 12), tumor (n = 6) and uncommon hematologic syndromes (n = 11). Laparoscopic splenectomy was attempted in every patient. The lateral approach was most commonly used with an anterior approach to the splenic hilar vessels, which were cut after hemostasis using a stapling gun; other techniques were also employed. RESULTS: The mean operating time was 165 minutes (45-360); it was shorter in the case of conversion (144 minutes) and became shorter with the operator's experience. Conversion was necessary in 55 patients (20%), due to hemorrhage in 2/3 of cases, related to splenic vessels (20 cases), short gastric vessels (9 cases), or injury of the spleen (8 cases). In ten cases (2%), conversion was necessary for extraction of the spleen. Conversion rate varied from 5.3 to 46.7%, depending on the surgical team. Univariate analysis of factors predisposing to conversion identified four causes: obesity; technique used to achieve hemostasis of the splenic hilar vessels; operator's experience; and presence of splenomegaly. An accessory spleen was found in 44 patients (16%). The weight of the spleen was more than 350 g in 43 patients (15.6%). There were no deaths. There were no significant complications in 236 patients (85.8%) and the mean hospital stay was 6.4 days. In comparison with patients who had a conversion, bowel function returned significantly earlier, use of analgesia was reduced and hospital stay was shorter. The overall morbidity rate was 13.8% (n = 38); morbidity rate was only 10.4% (n = 22) for laparoscopic splenectomy. In these 22 patients, the complications were: subphrenic collections (n = 5, 2.2%), abdominal wall infections (n = 5), thromboembolic events (n = 2), anemia (n = 2), pneumonia (n = 1), peptic ulcer (n = 1), bowel obstruction (n = 1), splenic vein thrombosis (n = 1). Re-operations were required in 4 patients (1.8%) because of hemorrhage, pancreatitis and bowel obstruction. Morbidity rate was significantly increased in the case of conversion (27%), obesity (20%), malignant disease (30%) and splenomegaly (21.8%). Forty-four patients (16%) received perioperative or postoperative blood transfusion and 23 (8.3%) received platelet transfusion. Mean time to return to normal activity was 21 days and was shorter in the absence of conversion (18.5 days versus 35 days). In patients with ITP, the mean platelet count was 240,000 after 3 months, and the failure rate was 8.3%. CONCLUSION: Laparoscopic splenectomy is a real alternative to conventional splenectomy for some hematologic diseases, particularly ITP and HA. The advantages are an uneventful postoperative course, a lower morbidity rate, a shorter hospital stay and an earlier return to normal activity. The limits of this technique are related to the operator's experience, the size of the spleen, the nature of the underlying disorders and patient characteristics, mainly obesity.  相似文献   
32.
33.
氯地滴眼液的含量测定   总被引:4,自引:0,他引:4  
目的:采用HPLC法测定氯地滴眼液中氯霉素和地塞米松磷酸钠的含量。方法:色谱分析条件:ODS柱作分析柱,流动相为甲醇/水体系,0 ̄8min使用40%甲醇,8 ̄16min使用60%甲醇,流速1ml/min,0 ̄9min240nm紫外检测,:二组分分离良好。各组各组性关系良好,平均回收率氯霉素99.8%(RSD=1.2%,n=5),地塞米松磷酸钠99.4%(RSD=0.7%,n=5),结论:该法用于氯  相似文献   
34.
35.
36.
PURPOSE: To compare the effects of recombinant activated factor VII (rFVIIa) and platelet-rich plasma (PRP) in an experimental model of bleeding and arterial thrombosis. METHODS: The Folts model was used in 60 rabbits. After anesthesia, the carotid artery was exposed and a 75% stenosis was induced. A compression injury of the artery triggered a series of cyclic flow reductions (CFRs). After counting baseline CFRs, animals were assigned randomly to one of four groups (n = 15 in each): control, PRP, rFVIIa and placebo. Control animals received 10 mL.kg(-1) of saline while 10 mL.kg(-1) of a hydroxyethyl starch solution (200,000/6%/0.5) were infused in the three other groups. CFRs were measured again, followed by treatment with PRP, rFVIIa or placebo and by a final measurement of CFRs. At the end of each observation period, an ear immersion bleeding time (BT) was measured and a blood sample was drawn for the evaluation of hematological variables. Microvascular bleeding was evaluated at the end of the experiment in grams of blood shed from liver and spleen sections. Results are presented as median (range). RESULTS: rFVIIa shortened the BT and decreased microvascular bleeding as compared with placebo [60 (35-100) sec vs 110 (50-140) sec, P = 0.0019 and 9 (4-24) g vs 17 (5-28) g, P = 0.002, respectively]. rFVIIa did not increase CFRs [3(0-9) vs |(0-5), P = 0.11]. CONCLUSION: rFVIIa led to a decrease in BT and microvascular bleeding but did not significantly affect arterial thrombosis in rabbits.  相似文献   
37.
Reeve  AE; Morris  CM; Fitzgerald  PH 《Blood》1988,72(1):24-28
A 45-year-old male patient with Ph-negative chronic myeloid leukemia (CML) had rearranged bcr-3' and bcr-5' gene regions in Southern blot studies when leukemia was diagnosed. During development of terminal blast crisis, successive blood samples showed a progressive decrease in the amount of germline bcr DNA and its complete loss by full blast crisis. There were also increased amounts of rearranged bcr DNA consistent with acquired homozygosity. A similar result was obtained with an IgV lambda probe and indicated homozygosity of a significant part of chromosome 22. The bcr-abl gene complex behaves as a somatic dominant in CML, and we suggest that its acquired homozygosity is a mechanism of bcr-abl amplification similar to duplication of the Ph chromosome commonly found in the blast crisis of CML.  相似文献   
38.
39.
40.
The neurotransmitters serotonin and dopamine both have a critical role in the underlying neurobiology of different behaviors. With focus on the interplay between dopamine and serotonin, it has been proposed that dopamine biases behavior towards habitual responding, and with serotonin offsetting this phenomenon and directing the balance toward more flexible, goal-directed responding. The present focus paper stands in close relationship to the publication by Worbe et al. (2015), which deals with the effects of acute tryptophan depletion, a neurodietary physiological method to decrease central nervous serotonin synthesis in humans for a short period of time, on the balance between hypothetical goal-directed and habitual systems. In that research, acute tryptophan depletion challenge administration and a following short-term reduction in central nervous serotonin synthesis were associated with a shift of behavioral performance towards habitual responding, providing further evidence that central nervous serotonin function modulates the balance between goal-directed and stimulus-response habitual systems of behavioral control. In the present focus paper, we discuss the findings by Worbe and colleagues in light of animal experiments as well as clinical implications and discuss potential future avenues for related research.  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