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   1682篇
  免费   58篇
  国内免费   16篇
耳鼻咽喉   69篇
儿科学   70篇
妇产科学   95篇
基础医学   125篇
口腔科学   33篇
临床医学   123篇
内科学   381篇
皮肤病学   114篇
神经病学   89篇
特种医学   59篇
外科学   339篇
综合类   32篇
一般理论   1篇
预防医学   41篇
眼科学   63篇
药学   67篇
中国医学   3篇
肿瘤学   52篇
  2024年   2篇
  2023年   12篇
  2022年   18篇
  2021年   48篇
  2020年   31篇
  2019年   37篇
  2018年   46篇
  2017年   39篇
  2016年   46篇
  2015年   72篇
  2014年   67篇
  2013年   91篇
  2012年   120篇
  2011年   133篇
  2010年   81篇
  2009年   71篇
  2008年   118篇
  2007年   138篇
  2006年   129篇
  2005年   105篇
  2004年   100篇
  2003年   68篇
  2002年   66篇
  2001年   15篇
  2000年   16篇
  1999年   19篇
  1998年   8篇
  1997年   12篇
  1996年   3篇
  1995年   4篇
  1994年   2篇
  1993年   9篇
  1992年   6篇
  1991年   6篇
  1990年   4篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1985年   1篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
排序方式: 共有1756条查询结果,搜索用时 10 毫秒
11.
12.
13.
OBJECTIVE: To establish the adenosine deaminase (ADA) activity in women who had been pregnant with a child suffering from central nervous system (CNS) anomaly. METHODS: The study group comprised 68 women who had been pregnant with an affected child, and 68 controls matched for age, gestational age and body mass index. Maternal venous blood was collected for measurement of ADA levels. We defined the diagnostic sensitivity, specificity and area under receiver-operating characteristic curve for ADA. RESULTS: Plasma ADA activity was significantly higher in the study group (12.3 U/L, range 1.7-33.3) compared to the median value of 3.3 U/L (range 1.1-34.4) in normal pregnancies (P<0.05). The cut-off point of ADA >5.9 U/L was associated with the highest combination of specificity (58.8%) and sensitivity (86.8%). CONCLUSION: ADA activity in women who have conceived a fetus with CNS malformations was significantly higher than that in normal pregnant women.  相似文献   
14.
Benzodiazepines such as diazepam are widely prescribed as anxiolytics and sleep aids. Continued use of benzodiazepines, however, can lead to addiction in vulnerable individuals. Here, we investigate the neural mechanisms of the behavioral effects of benzodiazepines using the intracranial self-stimulation (ICSS) test, a procedure with which the reward-enhancing effects of these drugs can be measured. Benzodiazepines bind nonselectively to several different GABAA receptor subtypes. To elucidate the α subunit(s) responsible for the reward-enhancing effects of benzodiazepines, we examined mice carrying a histidine-to-arginine point mutation in the α1, α2, or α3 subunit, which renders the targeted subunit nonresponsive to diazepam, other benzodiazepines and zolpidem. In wild-type and α1-point-mutated mice, diazepam caused a dose-dependent reduction in ICSS thresholds (reflecting a reward-enhancing effect) that is comparable to the reduction observed following cocaine administration. This effect was abolished in α2- and α3-point-mutant mice, suggesting that these subunits are necessary for the reward-enhancing action of diazepam. α2 Subunits appear to be particularly important, since diazepam increased ICSS thresholds (reflecting an aversive-like effect) in α2-point-mutant animals. Zolpidem, an α1-preferring benzodiazepine-site agonist, had no reward-enhancing effects in any genotype. Our findings implicate α2 and α3 subunit containing GABAA receptors as key mediators of the reward-related effects of benzodiazepines. This finding has important implications for the development of new medications that retain the therapeutic effects of benzodiazepines but lack abuse liability.  相似文献   
15.
16.
In this study, the effects of the wound‐covering materials, Acticoat® and Cutinova Hydro®, on wound healing have been studied in rabbit models with open and tissue‐lost wounds with full‐thickness flank excisions. Rabbits were used as subjects with three groups of four rabbits each, and trial periods of 7, 14 and 21{\uns}days. Four circular wounds, of 1.5 cm diameter were made two on the right (one of them control) and two on the left (one of them control) of the dorsal sides of the abdomen. Acticoat® and Cutinova Hydro® were applied on the wounds with suture for a period of 21 days and one each placed on the right and left sides as control with gauze. Biopsy specimens were taken from the animals at the end of the research period to check the length of the epithelium, epithelial thickness, size of wounds, wound granulation tissue formation and histopathological evaluation for clarity. The Acticoat® group showed better healing and scar formation compared to the Cutinova Hydro® group by macroscopic examination. Epithelial wound length and clarity in terms of statistical difference occurred on day 21 (P <0.05); while the length of the wound epithelium decreased patency, epithelial thickness on days~7, 14 and 21, showed no statistical differences (P >0.05). As a result, the Acticoat® wound dressing was determined as a more reliable for the early wound healing. This study has shown the short‐term clinical benefits of hydroactive, polyurethane dressings in the management of acute wounds. However, longer periods of wound healing procedure should be planned for reliable and safe results of wound dressing. It has also been concluded that microbiological analyses should be included for more robust and reliable comparisons.  相似文献   
17.
Introduction  The aim of the present study was to evaluate the effects of erythropoietin (EPO) on the histopathology of testes after unilateral testicular torsion and detorsion. Materials and methods  Twenty-five male Sprague–Dawley rats weighing 120 g were used in this study. The rats were randomly divided into three groups, a sham group consisting of five rats and the other two groups consisting of ten rats. In group 1 (sham group), right orchiectomy with no additional intervention was performed. In group 2 (T/D group), torsion was created by rotating the testis 720° in a clockwise direction for 4 h. After a 4-h torsion period, the right testis was detorted and replaced into the scrotum for 4 h. After the torsion, 0.5 cc 0.9% NaCl solution was injected once and three times in a week (total 12 doses). In group 3 (T/D + erythropoietin; EPO group), the same surgical procedure was done as in group 1, but EPO 1,000 IU/kg was injected just before the detorsion and three times in a week. At the end of each procedure, bilateral orchiectomies were performed for the histopathological examinations in all groups. Results  We examined the testes weight, vascularization of the region between the seminiferous tubules, percentage of necrotic seminipherous tubules, and maturation of spermatogenesis in terms of necrosis, sertoli cells, maturation arrest of spermatogenesis, hypospermatogenesis, and normal spermatogenesis of torsioned testis tissues with and without EPO treatment. Extremely significant differences in testicular weight were observed in group 1 compared to groups 2 and 3 (P < 0.001). Conclusion  Administration of EPO significantly influenced the rescue of testicular function by preserving the intact seminiferous tubular morphology, lowering the percentage of necrotic seminipherous tubules, and significantly reducing histological damage (P < 0.05).  相似文献   
18.
We investigated whether a proximal femoral nail (PFN) having two lag screws can be implanted without distal locking screws in AO/OTA 31-A1 and 31-A2 intertrochanteric femur fractures. Twenty-four patients with AO/OTA 31-A1 and 31-A2 fractures were treated with a PFN without distal interlocking by a single surgeon. The mean follow-up was 12 months (range: 7–23). Clinical and functional outcome was assessed according to the Harris hip score and Barthel’s activity score. The fractures healed in all patients; the average consolidation time was 14 weeks (range: 9–28). Fourteen patients had excellent and good results, nine patients had fair results, and one patient had a poor result according to the Harris hip score; 17 patients had a high range of mobility according to the Barthel activity score. Our results suggested that the PFN can be successfully implanted without distal interlocking in 31-A1 and 31-A2 fractures.  相似文献   
19.
20.
We report our success with somatostatin and propranolol to treat small-for-size syndrome that occurred despite splenic artery ligation. A 48-year-old woman with cirrhosis due to autoimmune hepatitis underwent living-donor liver transplant; her graft-to-body weight ratio of the right lobe was 0.91%. After arterial reperfusion, portal pressure and flow were 24 cm H20 and 2.22 L/min (ie, 360 mL/100g graft/min), respectively. Following splenic artery ligation, the portal pressure decreased to 16 cm H20 and portal flow to 1.74 L/min (ie, 282 mL/100g graft/min). On the second postoperative day, small-for-size syndrome was diagnosed based on the marked prolongation of prothrombin time (international normalized ratio, 4.4), hyperbilirubinemia (359.1 micromol/L), rapid escalation of transaminases (alanine aminotransferase 2488 U/L, aspartate aminotransferase 1075 U/L) and very high portal flow rate (> 90 cm/sec). Oral propranolol (40 mg/day b.i.d.) and somatostatin infusion (250-microgram bolus followed by perfusion at a rate of 250 microgram/h for 5 days) were started. Prothrombin time and transaminase levels began to decrease the following day, although the bilirubin level increased to 495.9 micromol/L before returning to normal. The patient was discharged in excellent health 5 weeks after surgery. Despite reduction of portal pressure by splenic artery ligation, small-for-size syndrome may develop in patients with persistent high portal flow. To the best of our knowledge, this is the first report of the successful treatment of small-for-size syndrome by somatostatin and propranolol in the clinical setting.  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