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   382087篇
  免费   24439篇
  国内免费   2829篇
耳鼻咽喉   5226篇
儿科学   8244篇
妇产科学   10109篇
基础医学   53444篇
口腔科学   11912篇
临床医学   30389篇
内科学   78957篇
皮肤病学   8615篇
神经病学   27381篇
特种医学   13998篇
外国民族医学   82篇
外科学   61016篇
综合类   10102篇
现状与发展   1篇
一般理论   64篇
预防医学   17645篇
眼科学   9629篇
药学   31130篇
  1篇
中国医学   2223篇
肿瘤学   29187篇
  2021年   2715篇
  2019年   2809篇
  2018年   4657篇
  2017年   3524篇
  2016年   3604篇
  2015年   4123篇
  2014年   5829篇
  2013年   7527篇
  2012年   10203篇
  2011年   10450篇
  2010年   6308篇
  2009年   5943篇
  2008年   9624篇
  2007年   10463篇
  2006年   10393篇
  2005年   9403篇
  2004年   8943篇
  2003年   8655篇
  2002年   8275篇
  2001年   28304篇
  2000年   28827篇
  1999年   23699篇
  1998年   5178篇
  1997年   4267篇
  1996年   3847篇
  1995年   3489篇
  1994年   3111篇
  1993年   2856篇
  1992年   16083篇
  1991年   14839篇
  1990年   14177篇
  1989年   13990篇
  1988年   12612篇
  1987年   12086篇
  1986年   11123篇
  1985年   10332篇
  1984年   6918篇
  1983年   5608篇
  1982年   2721篇
  1979年   5487篇
  1978年   3348篇
  1977年   2979篇
  1975年   2647篇
  1974年   3072篇
  1973年   2867篇
  1972年   2835篇
  1971年   2781篇
  1970年   2516篇
  1969年   2545篇
  1968年   2253篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Twenty five patients with renal vasculitis presenting over an eight year period were reviewed. Ten had microscopic polyarteritis, 6 classic polyarteritis, 5 overlap syndrome, 2 Churg-Strauss syndrome and 2 Wegener’s granulomatosis. Clinical features included hypertension, pulmonary involvement, neurological involvement and arthralgia. Serum creatinine was over 500 umol/1 in 13 patients, 10 of whom required dialysis. Visceral angiography was positive in 80% of those studied, Focal and segmental necrotising glomerulonephritis was the commonest renal lesion. Treatment consisted of corticosteroids and cytotoxic agents in most cases. Plasmapheresis was used for rapidly progressive renal failure, severe pulmonary haemorrhage or cerebral vasculitis. Improvement or stabilisation of renal function was seen in 68% of patients treated. There were 4 early deaths and one late death. The diagnosis, histology, treatment and outcome of renal vasculitis is discussed. The importance of early diagnosis and treatment is emphasised in this potentially reversible cause of acute renal failure.  相似文献   
992.
Trial use of CES-D with 550 normal persons   总被引:94,自引:0,他引:94  
  相似文献   
993.
994.
995.
A newly established cancer marker, the PFK inhibition test, has been further examined for its capacity to detect malignant neoplasms irrespective of the organs in which cancer cells start proliferating. We tested 1,160 sera from cancer patients and compared them with 756 normal sera, using histograms and normal paper for analysis of accumulated frequency. PFK activity through the influence of normal sera showed normal distribution, and cancerous sera shifted to the inhibitory site with an irregular shape. From these analyses, the patients were classified into the following types: normal range: PFK greater than SD (standard deviation of PFK activity in normal sera); suspicious range: SD greater than PFK greater than 2SD, must be given the PFK test again; and dangerous range: PFK less than 2SD, further examination must be carried out to detect cancer. Fifty percent of the sera from all the cancer patients inhibited PFK beyond 2 SD of normal sera. We also analyzed organ-associated PFK distribution, eg, gastric, colorectal, and mammary cancer. In gastric cancer, PFK inhibition was stronger in accordance with how far a particular stage of cancer had progressed. However, 50% of sera from stage I gastric cancer patients was positive beyond the cut-off line of 2 SD. We examined 104 sera from patients diagnosed as benign prostatic hypertrophy and found malignant cells in 10 patients whose sera tended to be positive in PFK inhibition. The PFK inhibitory factor in the body fluids of cancer patients was fractionated by Sephadex G-75 gel filtration and DEAE ion exchange chromatography. The approximate molecular weight of this factor was 13,000 daltons. The factor was resistant to heat and acid (0.1 N HCl and H2SO4) and was sensitive to 0.1 N NaOH and phosphate buffer. Diluted sulfuric acid and ammonium sulfate made an inactive NaOH-treated sample active when lyophilized following dialysis against distilled water. PFK inhibition by cancerous sera was eliminated by fructose-2,6-bisphosphate (the strongest activator of PFK) in a dose-dependent manner. PFK attached to agarose beads was found to be reversible even after being inhibited by cancerous body fluids and ATP water solution. Although PFK is apt to decay in a low pH range, the established procedure did not destroy PFK, but induced a direct inhibition of PFK by ATP through the ATP inhibition site on the PFK molecule. The PFK inhibitor may possibly function as a proton carrier and release protons to activate the ATP inhibition site.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
996.
997.
998.
999.
Non-hormonal adrenocortical adenoma with oncocytoma-like appearances   总被引:5,自引:0,他引:5  
We report a case of non-hormonal adrenocortical adenoma. The tumor was removed en block with the adrenal gland. The specimen was 5.0 X 4.5 X 3.0 cm, weighed 30 g and was solid. Histologically, this tumor had an oncocytoma-like appearance. However, as there is no concept of oncocytoma in connection with adrenocortical adenoma, this case was diagnosed as adrenocortical adenoma. A case with such histological findings has never been reported.  相似文献   
1000.
The effect of central scotomata on pattern reversal visual evoked potential (PVEP) was investigated in patients with maculopathy and healthy subjects. PVEP was evoked monocularly by both full-field and half-field stimulations. Since the latency of 'the major positivity at Oz' (P100-Oz) is used as the most reliable parameter in the clinical application of PVEP, special attention was focused on its changes, comparing with 'ipsilateral major positivity of half-field PVEP' (P100-IHF). Although the incidence of modification was lower in the patients, central scotomata modified PVEPs of the healthy subjects and of the affected eye of the patients in a similar manner: full-field PVEP showed prolonged latency and reduced amplitude of P100-Oz. Half-field PVEP disclosed prolonged P100-Oz latency with intact P100-IHF latency. Only difference was that amplitude reduction of both P100-Oz and P100-IHF of half-field PVEP was observed only in the healthy subjects. The prolonged P100-Oz latency of half-field PVEP was accompanied, both in the healthy subjects and in the patients, by a contralateral negative-positive complex (N105-P135) which was augmented and extended to Oz. The prolonged P100-Oz latency, thus, was due to the pronounced P135. These observations suggested that an attenuation of the afferent impulses from the central retina may cause a prolongation of the P100-Oz latency in both healthy subjects and patients, but this is not a reflection of the truly prolonged P100-IHF latency. It was concluded that, in the clinical application of PVEP, recordings of half-field PVEP from the lateral electrodes seem to be essential to distinguish true prolongation of the P100-Oz latency.  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