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   3395篇
  免费   204篇
  国内免费   37篇
耳鼻咽喉   84篇
儿科学   45篇
妇产科学   51篇
基础医学   391篇
口腔科学   32篇
临床医学   142篇
内科学   1042篇
皮肤病学   43篇
神经病学   339篇
特种医学   74篇
外科学   796篇
综合类   9篇
预防医学   69篇
眼科学   41篇
药学   157篇
中国医学   4篇
肿瘤学   317篇
  2024年   3篇
  2023年   37篇
  2022年   49篇
  2021年   92篇
  2020年   64篇
  2019年   99篇
  2018年   110篇
  2017年   84篇
  2016年   107篇
  2015年   88篇
  2014年   150篇
  2013年   154篇
  2012年   271篇
  2011年   252篇
  2010年   127篇
  2009年   110篇
  2008年   204篇
  2007年   222篇
  2006年   210篇
  2005年   212篇
  2004年   198篇
  2003年   189篇
  2002年   152篇
  2001年   25篇
  2000年   30篇
  1999年   46篇
  1998年   47篇
  1997年   37篇
  1996年   22篇
  1995年   18篇
  1994年   26篇
  1993年   14篇
  1992年   32篇
  1991年   27篇
  1990年   20篇
  1989年   13篇
  1988年   14篇
  1987年   15篇
  1986年   9篇
  1985年   9篇
  1984年   7篇
  1983年   6篇
  1982年   6篇
  1981年   6篇
  1979年   9篇
  1978年   3篇
  1977年   3篇
  1976年   2篇
  1967年   1篇
  1966年   1篇
排序方式: 共有3636条查询结果,搜索用时 15 毫秒
1.
2.
3.
Summary Total body bone mineral (TBBM) content in rats was measured by dual photon absorptiometry (DPA). TBBM showed significant increases over 4 weeks in control groups with significant bone loss over the same time in prednisolone-injected rats on low calcium feed. Daily injections of calcitonin significantly reduced loss of bone mass. Both prednisolone- and prednisolone-calcitonin-injected groups showed significantly elevated serum alkaline phosphatase with the prednisolone-calcitonin group also exhibiting elevated serum calcium and phosphate levels, confirming the impact of the experimental protocol. TBBM measured by DPA in all groups correlated well (r=0.928,P<0.001 n=20) with the total ash weight suggesting that the method reflects total skeletal mineral content in the small animal. TBBM measurement by DPA proves well-suited to monitoring bone mineral in a small animal experimental setting.  相似文献   
4.
Five hemiplegic patients with intractable epilepsy were studied with transcranial magnetic stimulation (TMS) before and after various surgical treatments. These patients had unilateral widespread cerebral lesions acquired at various times, including congenital, infantile and childhood injury. Motor evoked potentials (MEPs) of the abductor pollicis brevis (APB) muscles were simultaneously recorded on both sides following TMS of the motor cortex in the respective hemisphere using a figure-8 or circular coil. In all patients with congenital disease, the abolition of motor function in the affected hemisphere was estimated by magnetic MEPs, and the hemiplegia did not deteriorate after functional hemispherectomy (HS) was performed in two of them. In two patients with acquired disease, HS was not performed because it was shown by magnetic maps that the motor function in the affected hemisphere remained. Furthermore, it was shown by electric MEPs using subdural electrodes that a patient who had had encephalitis in early childhood had a reorganised motor area in the parietal cortex of the affected hemisphere. The present findings indicate that magnetic MEPs are a very useful non-invasive method of assessing whether the motor area in the affected hemisphere can be resected in hemiplegic patients with intractable epilepsy.  相似文献   
5.
This report presents the effect of repeated heating every 24 hrs using bleomycin (BLM) which, although seemingly contrary to the usual agreement that hyperthermia should be carried out with a long interval due to thermotolerance, holds many possibilities. FM3A cells on the foot pad of C3H mouse were immersed in a heated water bath at 43 and 44°C for 30 min. The effect of repeated heating was appreciated by an improved growth curve and 50 day survival compared to mice which received heating twice with a 96-hr interval. Repeated heating every 24 hrs 5 times with BLM suppressed tumor growth significantly as compared to heating twice with a 96-hr interval without BLM. The longest survival time was obtained by the repeated heating with BLM among all protocols. There is therefore a good possibility that more effective results could be obtained clinically by repeated heating over a short period.  相似文献   
6.
To evaluate clinical and pathological factors present at the initial consultation which affect disease progression, we reviewed data from 223 patients with superficial bladder cancer (pTa and pT1) who were initially treated at Nagoya University Hospital between January 1973 and December 1987. The factors included in the present analysis were age, sex, symptoms, interval between initial symptoms and first consultation, location of tumor, size, number, endoscopic shape, histological pattern of growth, grade and stage. The median duration of the follow-up after initial treatment was 46 months. Of the 223 patients, 17 died: 8 (3.6%) of bladder cancer and the remaining 9 (4.0%) of unrelated causes. Disease progression developed in 12 patients (5.4%): muscle invasion of the bladder wall in 11 and lung metastasis in one. The interval between initial treatment and progression ranged from 4 to 108 months, with a median of 11.5 months. Of the 12 patients, 9 (75%) had disease progression within 2 years. Progression was significantly associated with poor prognosis (p less than 0.001): the 5-year actuarial survival rates were 47.1% and 92.8% in patients with and without progression, respectively. Univariate analysis by Cox's proportional hazards model demonstrated that characteristics such as irritative bladder symptoms, higher-grade tumors, invasion into lamina propria, and nonpapillary growth seen at initial consultation were significantly related to disease progression. Cox's proportional hazards model produced hazard ratios of 10.2 in irritative bladder symptoms (yes vs. no), 6.3 in histological grade (grade 3 vs. grades 0-2), 4.9 in stage (pT1 vs. pTa), and 4.7 in pattern of growth (papillary vs. nonpapillary).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
7.
Laparoscopic surgery has been widely performed for removing the gallbladder and the pelvic lymph-nodes in recent years. We have applied laparoscopy technique to nephrectomy and here we describe our procedures and the clinical results. The patient is placed in the supine position under general anesthesia. After a 4 liter CO2 pneumoperitoneum is induced, five trocars are inserted into the abdominal cavity through the ipsilateral abdominal wall. The patient is then turned to the lateral position to displace the bowel medially. The ipsilateral colon is reflected medially after incision of the parietal peritoneum was made along the line of Todt to expose the retroperitoneum. The ureter was identified and dissected. It was secured with 4 clips (2 clips on the renal side and 2 on the distal side) and then cut with scissors. The renal vein and artery were then dissected and separately ligated with clips as described above. These vessels were also cut. The upper pole of the kidney was dissected out and the adrenal gland was left in place. The kidney thus became completely free within the abdomen. It was then grasped by the forceps through a 10 mm sheath positioned below the umbilicus. After incising the abdominal wall, the kidney was removed from the abdominal cavity with the grasping forceps and the sheath. By this procedure right nephrectomy was completely performed in a 56-year-old female patient and left nephrectomy in a 56-year-old male patient. The underlying disease was recurrent pyelonephritis secondary to renal calculi in both cases. The operative times were 221 min and 346 min, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
8.
9.
Recent studies have revealed that the phosphatidylinositol 3-kinase (PI3-K) pathway is involved in apoptotic cell death after experimental cerebral ischemia. The serine-threonine kinase, Akt, functions in the PI3-K pathway and prevents apoptosis by phosphorylation at Ser473 after a variety of cell death stimuli. After phosphorylation, activated Akt inactivates other apoptogenic factors, including glycogen synthase kinase-3beta (GSK3beta), thereby inhibiting cell death. However, the role of Akt/GSK3beta signaling in the delayed death of hippocampal neurons in the CA1 subregion after transient global cerebral ischemia (tGCI) has not been clarified. Transient global cerebral ischemia for 5 mins was induced by bilateral common carotid artery occlusion combined with hypotension. Western blot analysis showed a significant increase in phospho-Akt (Ser473) and phospho-GSK3beta (Ser9) in the hippocampal CA1 subregion after tGCI. Immunohistochemistry showed that expression of phospho-Akt (Ser473) and phospho-GSK3beta (Ser9) was markedly increased in the vulnerable CA1 subregion, but not in the ischemic-tolerant CA3 subregion. Double staining with phospho-GSK3beta (Ser9) and terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling showed different cellular distributions in the CA1 subregion 3 days after tGCI. Phosphorylation of Akt and GSK3beta was prevented by LY294002, a PI3-K inhibitor, which facilitated subsequent DNA fragmentation 3 days after tGCI. Moreover, transgenic rats that overexpress copper/zinc-superoxide dismutase, which is known to be neuroprotective against delayed hippocampal CA1 injury after tGCI, had enhanced and persistent phosphorylation of both Akt and GSK3beta after tGCI. These findings suggest that activation of the Akt/GSK3beta signaling pathway may mediate survival of vulnerable hippocampal CA1 neurons after tGCI.  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