全文获取类型
收费全文 | 932篇 |
免费 | 91篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 18篇 |
妇产科学 | 16篇 |
基础医学 | 111篇 |
口腔科学 | 17篇 |
临床医学 | 91篇 |
内科学 | 193篇 |
皮肤病学 | 3篇 |
神经病学 | 57篇 |
特种医学 | 241篇 |
外科学 | 99篇 |
综合类 | 27篇 |
预防医学 | 35篇 |
眼科学 | 11篇 |
药学 | 48篇 |
中国医学 | 1篇 |
肿瘤学 | 53篇 |
出版年
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2013年 | 12篇 |
2012年 | 14篇 |
2011年 | 24篇 |
2010年 | 21篇 |
2009年 | 12篇 |
2008年 | 16篇 |
2007年 | 35篇 |
2006年 | 19篇 |
2005年 | 31篇 |
2004年 | 27篇 |
2003年 | 24篇 |
2002年 | 23篇 |
2001年 | 27篇 |
2000年 | 23篇 |
1999年 | 18篇 |
1998年 | 24篇 |
1997年 | 28篇 |
1996年 | 19篇 |
1995年 | 21篇 |
1994年 | 32篇 |
1993年 | 20篇 |
1992年 | 23篇 |
1991年 | 18篇 |
1990年 | 30篇 |
1989年 | 36篇 |
1988年 | 37篇 |
1987年 | 35篇 |
1986年 | 24篇 |
1985年 | 38篇 |
1984年 | 30篇 |
1983年 | 26篇 |
1982年 | 21篇 |
1981年 | 22篇 |
1980年 | 18篇 |
1979年 | 15篇 |
1978年 | 17篇 |
1977年 | 15篇 |
1976年 | 15篇 |
1975年 | 5篇 |
1974年 | 15篇 |
1973年 | 9篇 |
1972年 | 5篇 |
1970年 | 6篇 |
1969年 | 6篇 |
1968年 | 6篇 |
1967年 | 7篇 |
1966年 | 7篇 |
排序方式: 共有1029条查询结果,搜索用时 15 毫秒
61.
The epidemiology and spectrum of surgical care in district hospitals of Pakistan 总被引:1,自引:0,他引:1 下载免费PDF全文
R J Blanchard M E Blanchard P Toussignant M Ahmed C M Smythe 《American journal of public health》1987,77(11):1439-1445
On-site surveys of 19 district-level hospitals in Pakistan revealed that, in 1983, 23,839 procedures were performed. There were 98 different types of operations. Thirty-eight per cent were classified as General Surgery, 30 per cent Gynecology and Operative Obstetrics, 19 per cent Urology, and 13 per cent Orthopedics. In three regions, population-based data were obtained from the 12 hospitals which provided all surgical care to discrete populations. The overall rate of surgical operations per 100,000 population was 124, 1.5 per cent to 9 per cent of the rate in western countries. The ratio of surgeons per 100,000 population was 0.36, 1/80 the ratio in the United States. There were almost twice as many operations per surgeon as in the USA. These data indicate a severe shortage of surgeons in Pakistan's district hospitals. They also provide the spectrum and relative numbers of different operations performed at the district level. This information has been useful along with other factors in designing a surgical curriculum at the Aga Khan University in Karachi, Pakistan. 相似文献
62.
Jeremy W Smith Osama Al-Khamees Brenda Costall Robert J Naylor James W Smythe 《Pharmacology, biochemistry, and behavior》2002,71(1-2):233-238
Epidemiological evidence suggests that nonsteroidal, anti-inflammatory drugs (NSAIDs) may retard the progression of Alzheimer's disease (AD). In the present study, we have chronically treated adult (4-5 months old) and aged (20+ months) rats with water adulterated with aspirin, and examined spatial learning in a swim maze. Adult rats (n=40) and aged rats (n=20) were divided into separate groups assigned to receive either normal drinking water or water with 2 mg/ml of aspirin dissolved in it. For 6 weeks, we monitored daily water and/or drug intake before testing all rats in a standard swim maze over an 8-day period. On average, each rat drank approximately 25 ml of water/day with no apparent control versus aspirin group differences. There was no effect of aspirin in young adult rats except during a visible platform trial where aspirin-treated rats performed better than controls. In contrast, aspirin markedly improved performance in the aged rats during hidden and visible platform trials. Such group differences abated by the eighth test day when all rats performed equally well. The improvements in performance were not correlated with changes in swim speeds indicating that the enhancement was not due to facilitated motor output. These data reveal that a modest, 6-week treatment regimen with aspirin in aged rats is sufficient to induce improvements in both speed of learning and strength of the learned response. We have yet to address the key question as to underlying physiological mechanism(s) that might underpin this augmented cognitive performance. Moreover, it would be useful to ascertain whether or not chronic NSAID treatment might reduce the extent of learning impairments in aged, cognitively impaired animals. 相似文献
63.
Gangadhar NL Rajasekhar M Smythe LD Norris MA Symonds ML Dohnt MF 《Revue scientifique et technique (International Office of Epizootics)》2000,19(3):793-799
Isolation of Leptospira from the kidneys of Rattus rattus wroughtoni hinton, Rattus rattus rufescens, Bandicota bengalensis and Bandicota indica was attempted in Bangalore in southern India. In total, 296 spirochaetes were isolated from 1,348 kidney cultures (an isolation rate of 22%). A batch of fifty-six isolates from India was identified, based on serological and polymerase chain reaction analysis, of which twenty-three isolates were identified as L. inadai by the World Health Organization/Food and Agriculture Organization Collaborating Centre for Reference and Research on Leptospirosis, in Brisbane. This is the first record of isolation of L. inadai from rodents. The preponderance of L. inadai in four different species of rodents suggests that these animals could be the natural reservoir hosts of L. inadai, and raises a critical question as to the likely impact of this species of Leptospira on the renal carrier status of other Leptospira pathogenic to humans and animals in this part of India. Virulence studies conducted at the University of Trieste in Italy, revealed that isolates of L. inadai from India were moderately or totally serum resistant when subjected to a serum killing test. To establish the possible seroprevalence of this species in the population, the inclusion of L. inadai in the battery of leptospiral antigens used for sero-epidemiological studies is recommended. 相似文献
64.
Picotamide inhibition of excess in vitro thromboxane B2 release by colorectal mucosa in inflammatory bowel disease. 总被引:1,自引:0,他引:1
Collins CE Benson MJ Burnham WR Rampton DS 《Alimentary pharmacology & therapeutics》1996,10(3):315-320
BACKGROUND: Inflammatory bowel disease is associated with increased mucosal release of eicosanoids. Among these, thromboxane A2 has been proposed as a possible inflammatory mediator; its suppression may be a useful therapeutic option. METHODS: Using a tissue incubation technique, we compared release of immunoreactive thromboxane B2 by colonic biopsies from patients with ulcerative colitis, Crohn's disease and controls, and assessed the inhibitory effect of picotamide, a thromboxane synthesis inhibitor-receptor antagonist, which has been widely used in Italy for management of ischaemic heart and cerebrovascular disease. RESULTS: Increased amounts of thromboxane B2 were released from biopsies from patients with active ulcerative colitis (median 238 pg/20 min/mg wet weight (interquartile range 147- 325), n = 12) and active Crohn's disease (252 (174-450), 6) compared with those from patients with quiescent ulcerative colitis (95 (61- 140), 12) or Crohn's disease (105 (57-201), 13), or controls (136 (64- 206), 8). Incubation with picotamide at concentrations between 100 microM and 1 mM reduced thromboxane B2 release (IC50 890 microM). CONCLUSION: Since increased thromboxane A2 production may have pathogenetic importance, thromboxane synthesis inhibitor-receptor antagonists such as picotamide merit therapeutic trial in the management of inflammatory bowel disease. 相似文献
65.
ATR is a caffeine-sensitive, DNA-activated protein kinase with a substrate specificity distinct from DNA-PK 总被引:19,自引:0,他引:19
ATR is a large, > 300 kDa protein containing a carboxy-terminus kinase domain related to PI-3 kinase, and is homologous to the ATM gene product in human cells and the rad3/MEC1 proteins in yeast. These proteins, together with the DNA-PK, are part of a new family of PI-3 kinase related proteins. All members of this family play important roles in checkpoints which operate to permit cell survival following many forms of DNA damage. We have expressed ATR protein in HEK293 cells and purified the protein to near-homogeneity. We show that pure ATR is a protein kinase which is activated by circular single-stranded, double-stranded or linear DNA. Thus ATR is a new member of a sub-family of PIK related kinases, founded by the DNA-PK, which are activated in the presence of DNA. Unlike DNA-PK, ATR does not appear to require Ku proteins for its activation by DNA. We show directly that, like ATM and DNA-PK, ATR phosphorylates the genome surveillance protein p53 on serine 15, a site which is up-regulated in response to DNA damage. In addition, we find that ATR has a substrate specificity similar to, but unique from, the DNA-PK in vitro, suggesting that these proteins have overlapping but distinct functions in vivo. Finally, we find that the kinase activity of ATR in the presence and absence of DNA is suppressed by caffeine, a compound which is known to induce loss of checkpoint control. Our results are consistent with the notion that ATR plays a role in monitoring DNA structure and phosphorylation of proteins involved in the DNA damage response pathways. 相似文献
66.
Mercado S; Hunter DW; Castaneda-Zuniga WR; Amplatz K; Young AT; Cardella JF; Lange PH; Hulbert JC; Reddy P 《Radiology》1986,158(1):207-209
Percutaneous nephrostolithotomy, which can require a double puncture, is presently the method of choice in our institution for the removal of renal stones. Patients that underwent this procedure were evaluated to identify the possible reasons for the double puncture. Of 200 patients evaluated, 14 needed a second tract. The three variables that determined whether a second puncture was needed, in order of importance, were number and size of the stones, with second tracts needed in patients with multiple stones and staghorn calculi; anatomical variations of the renal collecting system itself, with bifid systems the most significant anatomic variation; and the dexterity of the radiologist in performing the puncture and the ability of the urologist to extract the stone. Second tracts were needed more frequently in patients who presented with stones in both the lower and middle poles of the collecting systems. 相似文献
67.
Darcy MD; Cardella JF; Hunter DW; Smith TP; Castaneda-Zuniga WR; Lund G; Amplatz K 《Radiology》1986,161(3):611-614
The Amplatz retrievable vena caval filter was designed in an attempt to decrease complications associated with the placement of Mobin-Uddin or Kimray-Greenfield filters. The design allows percutaneous retrieval, thus expanding application of the filter to situations requiring temporary prophylaxis against pulmonary embolism. Filters have been placed in 16 patients, nine (56%) for prophylactic purposes. All filters were easily inserted percutaneously. Complications occurred in three patients; these included complete thrombosis of the inferior vena cava below the filter, misplacement of one filter into the pericaval retroperitoneal tissue, and development of thrombus cranial to the filter. With the current introduction system, the possibility of filter misplacement has been essentially eliminated. No patient experienced symptoms suggestive of pulmonary embolism after filter insertion. One filter retrieval has been performed, with no complications. 相似文献
68.
We describe the use of a modified sphygmomanometer to measure the strength of shoulder abductor muscles. Using a 5 x 5 Greco-Latin square design we compared the measurements of 5 physical therapists taken on 5 patients with rheumatoid arthritis with 2 cuff adaptations. The design variables explained 96.4% of the pressure readings, with patients accounting for 76.6%. There was no significant variation due to order of testing, cuff preparations or observers. The method is simple, portable, inexpensive, comfortable and safe to use. It can also be applied to 26 different muscle groups. 相似文献
69.
70.