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   33237篇
  免费   1748篇
  国内免费   148篇
耳鼻咽喉   360篇
儿科学   736篇
妇产科学   582篇
基础医学   6295篇
口腔科学   743篇
临床医学   2631篇
内科学   6283篇
皮肤病学   855篇
神经病学   3441篇
特种医学   1424篇
外科学   4602篇
综合类   152篇
一般理论   14篇
预防医学   1670篇
眼科学   721篇
药学   2319篇
中国医学   21篇
肿瘤学   2284篇
  2022年   161篇
  2021年   347篇
  2020年   295篇
  2019年   493篇
  2018年   574篇
  2017年   439篇
  2016年   566篇
  2015年   653篇
  2014年   784篇
  2013年   1171篇
  2012年   1643篇
  2011年   1760篇
  2010年   1185篇
  2009年   1134篇
  2008年   1891篇
  2007年   1930篇
  2006年   1798篇
  2005年   1925篇
  2004年   1804篇
  2003年   1766篇
  2002年   1845篇
  2001年   349篇
  2000年   273篇
  1999年   393篇
  1998年   503篇
  1997年   414篇
  1996年   369篇
  1995年   338篇
  1994年   291篇
  1993年   258篇
  1992年   213篇
  1991年   206篇
  1990年   170篇
  1989年   165篇
  1988年   170篇
  1985年   161篇
  1984年   181篇
  1983年   161篇
  1982年   198篇
  1981年   169篇
  1978年   135篇
  1933年   170篇
  1932年   180篇
  1931年   167篇
  1930年   169篇
  1929年   147篇
  1928年   163篇
  1927年   144篇
  1926年   158篇
  1925年   139篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Platelet aggregationin vitro, deterioration of visual field defects (VFD) and the prevalence of disc haemorrhages (DH) were assessed in 49 patients with primary open angle glaucoma (POAG) and compared with the findings for 67 individuals with suspected glaucoma (GS) in a seven-year follow-up study (range 5.8 to 8.2 years). The percentage patients with spontaneous platelet aggregation (SPA) was higher for POAG patients with visual field deterioration (60%) than both POAG patients without progressive loss of visual fields (12.5%; P<0.005) and those with suspected glaucoma (22.4%; P<0.005). The occurrence of DH was higher among POAG patients with progressive loss of visual field (28%) compared to the GS group (8.4%; P<0.025) and the group of patients consisting of POAG patients without deterioration of VFD and GS (9.9%; P<0.05). DH also occurred more often in patients with low tension glaucoma (41.6%) than in the remaining POAG patients (13.5%; P<0.05). No relation between the patients with SPA and the patients with DH was observed.Abbreviations NPB normal platelet behavior - SPA spontaneous platelet aggregation - DH disc haemorrhage  相似文献   
72.
In a prospective multicenter study of 1,052 patients with clinical signs of a scaphoid fracture, mammo-graphic films and fine intensifying screens were used at the radiographic examination. 5 standardized projections including 3 special projections focused on the scaphoid were taken. 150 fractures were diagnosed at the first examination but in 10 cases the fracture was first diagnosed at a second radiographic examination after 10-14 days.

The second examination still seems mandatory despite the use of high quality radiographs with optimal spatial resolution and contrast, and the value of supplementary special projections.  相似文献   
73.
Identification of a 28 kDa lychee allergen as a triose-phosphate isomerase   总被引:2,自引:0,他引:2  
The aim of this study was to investigate the allergenic potency of the exotic fruit lychee (Litchi chinensis SONN.). For this purpose the lychee protein extract was separated by ion exchange chromatography and a purified allergen with a molecular weight of 28 kDa was identified by N-terminal sequencing and peptide mass fingerprinting. Both methods determined the lychee allergen as a triose-phosphate isomerase. To this protein 67% of patients showed allergic reactions respectively IgE binding of their sera. Similar enzymes from other plants were also recognized as allergens.  相似文献   
74.
The morphologic effects of androgen deprivation in the different lobes of the rat prostate were examined by light microscopic morphometry. The prostates of Wistar male rats (260-340 g) were fixed in situ by glutaraldehyde perfusion in castrated animals 1 week after gonadectomy and in intact animals. The ventral (VP), dorsal (DP), and lateral (LP) lobes as well as the coagulating gland (CG) were dissected out, weighed, and processed for light microscopy. Using stereologic methods the following parameters were estimated for each lobe: volume fraction of connective tissue, epithelium and glandular lumina, average epithelial height, average epithelial cell volume, and total number of epithelial cells. Castration leads to a 58-76% reduction of the wet weight of all prostatic lobes. The decrease of glandular tissue is greater in VP than in LP, DP, and CG. In VP and LP, there is a 39-45% reduction of the epithelial height, and this effect is less pronounced in DP and CG. For all lobes, the shrinkage of average epithelial cell volume is in the same range (25-30%). Moreover, in VP and LP, there is a 70% reduction of the total number of cells, whereas the reduction is less in DP and CG. It thus seems that the reduction of prostatic epithelial tissue mass upon castration is due to a reduction of the number of cells as well as a reduction of the volume of individual cells. VP and LP appear to be more androgen-dependent than DP and CG.  相似文献   
75.
In a prospective multicenter study 1115 hip fracture patients were registered in Rotterdam (The Netherlands), Sundsvall and Lund (Sweden). The patients had similar background parameters with a mean age of 78 years, about half of them living alone and just above 80 percent coming from independent living

For cervical fracture, hemiarthroplasty was the predominating treatment in Rotterdam (n 169), whereas osteosynthesis was used in Sundsvall (screws n 135) and Lund (hook-pins n 148). The mean (median) hospitalization time was 32 (20) days in Rotterdam, 16 (12) days in Sundsvall, and 17 (10) days in Lund. Discharge to independent living varied from 53 percent in Lund to 72 percent in Sundsvall. Functional outcome (walking ability and ADL capacity) was at 4 months similar in all groups, but at 2 weeks was lower in Rotterdam. Mortality at 2 weeks / 1 month 14 months was in Rotterdam 4/9/20, in Sundsvall 2/4/13, and in Lund 01311 0 percent.

Trochanteric fractures were treated by screwplate in Rotterdam (n 146) and Lund (n 78), and by Ender nails in Sundsvall (n 11 7). The mean (median) hospitalization time was in Rotterdam 39 (29) days, in Sundsvall 24 (1 5) days and in Lund 19 (11) days. Discharge to independent living varied from 41 percent in Lund to 57 percent in Sundsvall. Functional outcome was similar between the groups. Mortality at 2 weeks / 1 month 14 months was in Rotterdam 2/6/14, in Sundsvall 611 2/19 and in Lund 12/12/18 percent.

Thus, our study has shown that it is possible to perform a prospective multicenter study involving different European countries. The functional out- come after 4 months was very consistent between the centers studied, irrespective of choices made concerning operation method and rehabilitation routines. However, a difference in mortality within these first postoperative months was found, which seems attributable to the operation procedure.  相似文献   
76.
77.
More suicides than expected (standardized mortality ratio=1.3; 95% confidence interval=1.1-1.6) compared to the population risk were found among Danish women with a diagnosis of non-melanoma skin cancer in the period 1971-1999 but not among men. The increased risk might be associated with a different personality type in this cancer group.  相似文献   
78.
79.
OBJECTIVE: The final outcome of patients with small cell lung cancer (SCLC) is poor with an overall 5-year survival rate of less than 10%. Therefore, the question of surgery in patients with a technically-operable solitary tumor has been raised. The purpose of this study was to identify the proportion of patients with operable SCLC and to assess the prognosis of different treatment strategies. For patients who were operated, we compared the resection specimens from patients with more than 5-year survival with those with shorter survival to see whether the specimens belonged to different subclasses of SCLC. METHODS: In Norway all clinical and pathologic departments submit reports on cancer patients to the Cancer Registry. The Registry also has a law-regulated authority to collect supplemental information regarding diagnosis, treatment and outcome for all cancer patients from the hospitals in charge. All reports on patients diagnosed as having SCLC in limited disease or unknown stage during the time interval 1993-1999 were reviewed. Patients with a T2-tumor, in whom a pneumonectomy would have to be performed, were classified as potentially operable. Five-year relative survival was calculated for patients diagnosed in 1993-1997. RESULTS: During the actual period 2442 individuals with SCLC were identified. The majority was treated with conventional chemotherapy or concurrent chemoradiotherapy while 38 underwent surgical therapy. Following reclassification of 697 patients reported to have limited disease or unknown stage 180 were judged to be in stage I. In addition to the 38 resected patients 14 were considered fit for surgery technically and medically while 97 were found to be potentially operable treatment modalities apart from surgery yielded a 5-year survival rate <7%. For stage I (N=96) the rate was 11.3% in conventionally treated patients compared to 44.9% for those who underwent surgical resection. By pathological review of surgical specimens a diagnosis of SCLC was confirmed in all patients treated by surgery in the groups with long and short survival. CONCLUSION: This investigation demonstrates that patients with SCLC having a peripherally located tumor should be referred to surgery, as long time survival is far better than for conventionally treated patients.  相似文献   
80.
Erythropoietic protoporphyria (EPP) is a disease of the heme metabolism due to a deficiency of ferrochelatase, leading to accumulation of protoporphyrin (PPIX) in the erythrocyte (red blood cell [RBC]). The major clinical manifestation in EPP is photosensitivity; however, in a small number of patients liver failure is a significant complication and liver transplantation is the only treatment option. Damage to both abdominal skin and organs occurs when exposed to operating light; however, this problem can be ameliorated by the use of filters that block the transmission of light with wavelength below 470 nm. A more unusual but very serious complication postoperatively is severe motor neuropathy, with few or no known acute available precautions. An effective treatment option is needed to manage EPP crises and to prevent complications after liver transplantation. We successfully treated a patient with EPP-induced liver failure with the molecular adsorbents recirculating system (MARS) and Prometheus in independent sessions. Following treatment with MARS we found a 9.1% reduction of the RBC-PPIX concentration and a 5.9% reduction after treatment with the Prometheus system. Plasmapheresis made a reduction in RBC-PPIX concentration of 0.8%. Following treatment sessions with MARS and Prometheus, the clinical condition was markedly improved and orthotopic liver transplantation was performed without further complications. In conclusion, extracorporeal therapy with MARS or Prometheus seems to be efficient in reducing RBC-PPIX concentration in comparison to plasma exchange.  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