全文获取类型
收费全文 | 1195篇 |
免费 | 102篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 43篇 |
妇产科学 | 8篇 |
基础医学 | 148篇 |
口腔科学 | 51篇 |
临床医学 | 114篇 |
内科学 | 268篇 |
皮肤病学 | 42篇 |
神经病学 | 65篇 |
特种医学 | 155篇 |
外国民族医学 | 1篇 |
外科学 | 82篇 |
综合类 | 55篇 |
预防医学 | 93篇 |
眼科学 | 5篇 |
药学 | 73篇 |
中国医学 | 2篇 |
肿瘤学 | 95篇 |
出版年
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 14篇 |
2018年 | 16篇 |
2017年 | 15篇 |
2016年 | 17篇 |
2015年 | 35篇 |
2014年 | 23篇 |
2013年 | 35篇 |
2012年 | 35篇 |
2011年 | 49篇 |
2010年 | 43篇 |
2009年 | 63篇 |
2008年 | 34篇 |
2007年 | 31篇 |
2006年 | 28篇 |
2005年 | 29篇 |
2004年 | 44篇 |
2003年 | 23篇 |
2002年 | 24篇 |
2001年 | 14篇 |
2000年 | 16篇 |
1999年 | 33篇 |
1998年 | 55篇 |
1997年 | 65篇 |
1996年 | 56篇 |
1995年 | 46篇 |
1994年 | 44篇 |
1993年 | 39篇 |
1992年 | 20篇 |
1991年 | 22篇 |
1990年 | 38篇 |
1989年 | 27篇 |
1988年 | 33篇 |
1987年 | 30篇 |
1986年 | 35篇 |
1985年 | 17篇 |
1984年 | 19篇 |
1983年 | 15篇 |
1982年 | 19篇 |
1981年 | 7篇 |
1980年 | 12篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1973年 | 8篇 |
1970年 | 3篇 |
1968年 | 5篇 |
排序方式: 共有1306条查询结果,搜索用时 15 毫秒
1.
2.
Complications associated with central venous catheters inserted in critically ill neonates 总被引:2,自引:0,他引:2
V Hruszkewycz P C Holtrop D G Batton R S Morden P Gibson J D Band 《Infection control and hospital epidemiology》1991,12(9):544-548
OBJECTIVE: To assess the incidence and spectrum of complications associated with central venous catheter (CVC) placement in the critically ill infant. DESIGN: A prospective study of all babies hospitalized in a neonatal intensive care unit (NICU) from January 1989 to December 1989. Potential risk factors associated with infection were evaluated by a case-control comparison. SETTING: Conducted at a university-affiliated, tertiary care community hospital. PATIENTS: Neonates requiring intensive care and a central venous catheter. Controls consisted of noninfected babies. RESULTS: Of 263 critically ill neonates, only 13 (4.9%) required a CVC insertion. Seventeen CVCs were placed in these 13 neonates for a total duration of 600 days (median, 32 days/cannula). Fifteen (88%) of these cannulas had one or more complications during its catheter life including dislodgement or leakage (53%), occlusion or thrombosis (47%), infections (29%), or minor bleeding (12%). Five babies (29%) developed 6 episodes of bloodstream infection including 3 sporadic cases due to Staphylococcus epidermidis and a cluster of fungemia due to Malassezia furfur associated with lipid emulsion therapy. Infants with a CVC-associated infection were a younger gestational age (24 weeks versus 32 weeks, p = .04) and weighed less at birth (580 g versus 1285 g, p = .02). The overall rate of bloodstream infection was one episode per 100 days of catheter use. CONCLUSIONS: CVCs may be lifesaving to a critically ill neonate, but complications occur frequently. Use must be restricted to infants in whom alternate delivery routes of intravenous therapy or support are otherwise unavailable. 相似文献
3.
4.
5.
The presence of vascular permeability factors in the extracellular products (ECP) of 10 strains of Renibacterium salmoninarum with different geographical origin and serological characteristics are reported. All the ECP produced haemorrhagic and/or oedematous zones at the injection site with a diameter ranging from 10-30 mm. However, the ECP samples did not display toxic effect in fish at the same dose as inoculated in rabbit (180-400 micrograms protein/0.1 ml). No differences were observed in the production of this dermatotoxic factor between the two antigenic groups found in this microorganism. Whereas heating (80 and 100 degrees C/15 min) the ECP samples resulted in a complete loss of their proteolytic activity, only a decrease (but not total inactivation) of the dermatotoxic effects was detected. Therefore, although proteases could be implicated in the permeability factor, they are not totally responsible for this activity. 相似文献
6.
Protein synthesis patterns of the low-virulence Naegleria fowleri LEE strain from axenic culture, the same strain after mouse brain passage to increase virulence, and the same strain after growth on bacteria were studied. Comparisons of accumulated proteins, in vivo-synthesized proteins, and in vitro-synthesized proteins translated from poly(A)+ mRNA were made. Differences between amoebae from the different treatments were noted. After 6 months in axenic culture, pathogenic protein synthesis patterns were lost and there was a decrease in virulence. Therefore, the increase in virulence is correlated with numerous specific changes in protein synthesis. 相似文献
7.
8.
There is growing evidence that arachidonic acid (AA) and/or its metabolites may be involved in the control of insulin secretion. We have now investigated the effect of AA on insulin secretion from rat islets, and the possible involvement of protein kinase C (PKC) in this process. Exogenous AA stimulated insulin secretion from intact islets at a substimulatory concentration of glucose (2 mM), but did not further enhance glucose-induced (20mM) insulin secretion. AA-induced insulin secretion was temperature dependent. The secretory responses seen at 37 degrees C were totally abolished by reducing the incubation temperature to less than or equal to 34 degrees C. AA-induced insulin secretion was not dependent upon extracellular Ca2+ and was potentiated by omission of Ca2+ or bovine serum albumin from the media. PKC in rat islets can thus be stimulated by AA, but the stimulation of PKC is not required for AA-induced insulin secretion. 相似文献
9.
S. van Ruth† EBL van Dorst‡ MR Canninga-van Dijk§ MS de Bruin-Weller† 《Journal of the European Academy of Dermatology and Venereology》2007,21(5):678-680
Cutaneous metastasis of vaginal carcinoma is extremely rare. So far, the total number of reported skin metastasis of vaginal carcinoma is only one. We present another case with an unusual manifestation of vagina carcinoma metastasis: skin metastasis presenting as a leg ulcer on the lower leg. 相似文献
10.
Arlene S. King William J. Threlfall Pierre R. Band Richard P. Gallagher 《American journal of industrial medicine》1994,26(1):125-132
The mortality profile of female nurses and teachers in British Columbia (BC) was examined using age-standardized proportional mortality ratios (PMRs) calculated for the period 1950–1984. Lowered overall mortality among nurses was seen for degenerative heart disease and for cerebrovascular accidents. Significantly elevated PMR values were observed for cancer of the breast and ovary in nurses of age 20–65 years. PMRs were significantly elevated for cancer of the pancreas and leukemia among those age 20 years and older. Elevated values were also observed for motor vehicle accidents and suicide among nurses in both age groups. Lower than expected mortality from degenerative heart disease and cerebrovascular accidents was seen in working age teachers (age 20–65 years). However, elevated PMRs were detected for carcinoma of the colon, breast, endometrium, brain, and melanoma. Among those 20 years and over, significantly elevated PMRs were also observed for cancers of the ovary and other digestive organs. Elevated PMRs were found for motor vehicle and aircraft accidents. Mortality from cirrhosis of the liver was lower than anticipated in both teachers and nurses. A number of significant PMRs declined when deaths of “homemakers” were withdrawn from the comparison group used to generate PMR values, suggesting that risk of death from various causes among women working outside the home differ from those seen in women who are predominantly in the home. 相似文献