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   15317篇
  免费   651篇
  国内免费   108篇
耳鼻咽喉   110篇
儿科学   271篇
妇产科学   185篇
基础医学   1817篇
口腔科学   284篇
临床医学   908篇
内科学   3833篇
皮肤病学   266篇
神经病学   1159篇
特种医学   550篇
外科学   2809篇
综合类   50篇
预防医学   364篇
眼科学   274篇
药学   1421篇
中国医学   63篇
肿瘤学   1712篇
  2023年   57篇
  2022年   122篇
  2021年   196篇
  2020年   103篇
  2019年   152篇
  2018年   223篇
  2017年   204篇
  2016年   241篇
  2015年   246篇
  2014年   339篇
  2013年   396篇
  2012年   696篇
  2011年   845篇
  2010年   521篇
  2009年   434篇
  2008年   791篇
  2007年   890篇
  2006年   893篇
  2005年   957篇
  2004年   836篇
  2003年   919篇
  2002年   982篇
  2001年   444篇
  2000年   451篇
  1999年   422篇
  1998年   247篇
  1997年   197篇
  1996年   184篇
  1995年   154篇
  1994年   160篇
  1993年   165篇
  1992年   294篇
  1991年   293篇
  1990年   269篇
  1989年   245篇
  1988年   245篇
  1987年   231篇
  1986年   198篇
  1985年   200篇
  1984年   116篇
  1983年   99篇
  1982年   52篇
  1981年   41篇
  1980年   38篇
  1979年   79篇
  1978年   40篇
  1977年   28篇
  1976年   18篇
  1975年   21篇
  1969年   13篇
排序方式: 共有10000条查询结果,搜索用时 23 毫秒
21.
OBJECTIVE: Tubularized incised plate urethroplasty has become a popular technique for repairing distal and proximal hypospadias in many institutions. Dorsal inlay graft urethroplasty has been used in our institution since 2003 to reduce the risk of meatal stenosis. In the present study, we evaluated the results of the dorsal inlay graft procedure. METHODS: A total of 28 patients with no deep groove and no severe curvature underwent one-stage urethroplasty using an inner preputial-based dorsal inlay graft. The medical records of all patients were retrospectively reviewed with regard to complication rate and cosmetic appearance. RESULTS: Mean patient age at surgery was 21 months (range, 14 months to 4.6 years). Preoperatively the urethral meatus was coronal in two cases, distal shaft in 17, proximal shaft in six and penoscrotal in three. Nine patients required testosterone therapy before surgery. Mean operative time was 200 min (range, 154-249 min). Mean length of inlay graft was 20.9 mm (range, 12-30 mm). In all patients, a straight penis was achieved without dorsal plication of the corposa cavernosa, and the neomeatus with a slit-like appearance was positioned at the glans tip. At a mean of 22 months of follow up, a urethrocutaneous fistula developed in only one patient (3.6%), requiring repair surgery 6 months after urethroplasty. No patient had meatal stenosis, neourethral stricture or urethral diverticulum along the inlay graft. CONCLUSION: Dorsal inlay graft urethroplasty is an effective method for hypospadiac repair and leads to good cosmetic outcome with low risk of complications.  相似文献   
22.
PURPOSE: To determine the effect of an interposition nerve graft on sexual function after radical prostatectomy. METHODS: This study includes 64 patients, without hormonal therapy, who underwent a radical prostatectomy and intraoperative electrophysiological confirmation of cavernous nerve preservation. Twelve patients underwent a unilateral interposition sural nerve graft (UNG) for the resected neurovascular bundle. Twenty-one and 31 patients underwent bilateral nerve-sparing (BNS) and unilateral nerve-sparing (UNS) surgery without a nerve graft, respectively. As the age of patients was significantly younger in the UNG group than in the other groups, age-matched analysis also was conducted. Sexual function, evaluated by a self-administered questionnaire using the University of California Los Angeles-Prostate Cancer Index, was compared statistically among the three groups. RESULTS: In the age-matched analysis, the postoperative sexual function (SXF) score of the UNG group showed an intermediate level of recovery between those of the BNS and UNS groups at 12 months and reached the same level as the score at 12 months of the BNS group at 18 months postoperatively. The difference in the SXF score between the UNG and UNS groups began to appear after 6 months postoperatively and increased steadily with time. However, the background factors, such as the baseline SXF score, the usage rate of phosphodiesterase 5 inhibitors, and the rate of comorbidities were different between the UNG and UNS groups. CONCLUSIONS: The difference of the SXF score between the UNG and UNS groups increased with time after 6 months postoperatively. However, it might be difficult at present to attribute a better recovery of the SXF score to the nerve graft because of the difference in the background factors between the groups.  相似文献   
23.
Background: Recent evidence suggested that propofol can deteriorate the cerebral oxygen balance compared with inhalational anesthetics. However, dose-related influences of propofol on cerebral oxygen balances were not clearly investigated. In the current study, the authors investigated the effects of increasing concentrations of propofol on jugular venous bulb oxygen saturation (Sjo2) in neurosurgical patients under normothermic and mildly hypothermic conditions.

Methods: After institutional approval and informed consent were obtained, 30 adult patients undergoing elective craniotomy were studied. Patients were randomly allocated to either normothermic or hypothermic group (n = 15 in each group). In the normothermic and hypothermic groups, tympanic membrane temperature was maintained at 36.5[degrees] and 34.5[degrees]C, respectively. Sjo2 was measured at predicted propofol concentrations of 3, 5, and 7 [mu]g/ml using a target-controlled infusion system in both groups.

Results: At a predicted propofol concentration of 3 [mu]g/ml, there were no significant differences in Sjo2 values between the normothermic and hypothermic groups, although the incidence of desaturation (Sjo2 < 50%) was significantly higher in the normothermic group than in the hypothermic group (30% vs. 13%; P < 0.05). Sjo2 values and the incidence of desaturation remained unchanged during the changes in predicted propofol concentration from 3 to 7 [mu]g/ml both in the normothermic and hypothermic groups.  相似文献   

24.
1. We have recently identified a candidate gene for rat genetic hypertension, termed Sa, by identifying an mRN A species that shows markedly higher expression in the kidneys of spontaneously hypertensive rats (SHR) than in those of Wistar-Kyoto rats (WKY). 2. Subsequent genetic co-segregation analyses by ourselves and others indicated that the Sa gene locus did indeed influence blood pressure. Moreover, in a preliminary association study, we found an association of a polymorphism of the human Sa gene with essential hypertension. 3. Further studies to identify functions of the Sa gene products are required before reaching a definite conclusion.  相似文献   
25.
An aggressive pancreatectomy was performed on a 53 year old Japanese man with advanced cancer of the pancreas. The tumor originated from the body of the pancreas and invaded the stomach, duodenum, left kidney, transverse colon and common hepatic artery. An unexpected cancer was also found in the head of the pancreas during the operation. Therefore, total pancreatectomy, total gastrectomy, left adrenonephrectomy, resection of the left transverse colon and dissection of the regional lymph nodes were performed. Resection of the common hepatic artery was also performed, followed by an end-to-end anastomosis between the common hepatic artery and celiac trunk. The postoperative course was uneventful and the patient was doing well until nine months after the operation when multiple metastatic lesions were noted in the liver. He died 391 days after the operation from hepatic failure.  相似文献   
26.
We studied subsets and cytotoxicity of recombinant interleukin-2 (rIL-2) expanded tumor infiltrating lymphocytes (TIL) from renal cell cancer (RCC) patients. TIL were successfully expanded in 13 of 14 RCC cases using anti-CD3 during initial 48 hours of culture. Percentages of CD8 positive cells among rIL-2 expanded TIL at 1 tp 4 week(s) of culture were 56.2 +/- 15.1% (range 26.2 to 79.8%, N = 13) and not necessarily predominant over CD4 positive cells. NK and LAK activities of TIL at 3 to 6 weeks of culture were 31.6 +/- 15.8% (range 1.4 to 57.4%, N = 9) and 16.6 +/- 11.6% (range 3.8 to 35.6%, N = 6), respectively. Autologous and allogeneic RCC cytotoxicity of TIL at 3 to 4 weeks of culture were 17.9 +/- 19.7% (range 0 to 47.6%, N = 4) and 18.9 +/- 14.8% (range 0 to 47.3%, N = 12), respectively. Since there was no statistical difference between them, autologous specific cytotoxicity was not demonstrated. From these results of present study, it is unlikely that most of effector cells of rIL-2 expanded TIL in autologous RCC lysis are major histocompatibility complex restricted cytotoxic T cells. And we concluded that it is doubtful that TIL is significantly superior over LAK cells in immunotherapy of human RCC.  相似文献   
27.
28.
The ultrastructural localization of adhalin and its relations to dystrophin, β-dystroglycan, and β-spectrin were studied in normal murine skeletal myofibers. The C-terminal peptides of adhalin and β-dystroglycan were synthesized based on their cDNAs, and the affinity-purified antibodies against these peptides were produced. Single-immunolabeling electron microscopy showed that the adhalin was located just inside the muscle plasma membrane or inside the myofiber a short distance from the plasma membrane. The adhalin signal was also noted at the sarcoplasmic side of plasmalemmd invaginations or at vesicular structures in subsarcolemmal areas. Double-immunogold-labeling electron microscopy disclosed a similar localization of dystrophin, β-dystroglycan, and β-spectrin. The close association of adhalin with dystrophin or β-dystroglycan was demonstrated by formation of doublets by signals of antibodies of adhalin with those of dystrophin or β-dystroglycan and was confirmed by statistical analyses. This study demonstrated that the location of adhalin is close to that of dystrophin and β-dystroglycan at the muscle plasma membrane.  相似文献   
29.
30.
A 65-year-old woman with diabetes mellitus and chronic otitis media developed headache, fever, and hoarseness, all of which did not responded to the oral antibiotics. As stiff neck and lower cranial nerve palsies appeared, bacterial meningitis was suspected. Neurological examination revealed the right hearing disturbance, right recurrent laryngeal nerve palsy, left sternocleidomastoid muscle atrophy and bilateral tongue atrophy. The CSF examination revealed mild pleocytosis and elevated protein, but no bacterial organism was cultured from the CSF. CT scans showed bilateral mastoiditis, and the right mastoid process and a posterior part of the petrous bone were eroded, indicating the exposed bony structures to the posterior fossa. MRI scans demonstrated the thickening of the dura mater of the posterior fossa and the right cerebellar tentorium. This is a rare example of bacterial pachymeningitis of the posterior fossa, the clinical symptoms and MRI findings of which resolved solely by antimicrobial agents without corticosteroid.  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