全文获取类型
收费全文 | 13886篇 |
免费 | 1124篇 |
国内免费 | 745篇 |
出版年
2024年 | 9篇 |
2023年 | 192篇 |
2022年 | 368篇 |
2021年 | 668篇 |
2020年 | 411篇 |
2019年 | 536篇 |
2018年 | 560篇 |
2017年 | 374篇 |
2016年 | 569篇 |
2015年 | 817篇 |
2014年 | 902篇 |
2013年 | 1057篇 |
2012年 | 1293篇 |
2011年 | 1103篇 |
2010年 | 687篇 |
2009年 | 614篇 |
2008年 | 755篇 |
2007年 | 646篇 |
2006年 | 592篇 |
2005年 | 507篇 |
2004年 | 451篇 |
2003年 | 357篇 |
2002年 | 324篇 |
2001年 | 224篇 |
2000年 | 186篇 |
1999年 | 205篇 |
1998年 | 146篇 |
1997年 | 147篇 |
1996年 | 123篇 |
1995年 | 117篇 |
1994年 | 114篇 |
1993年 | 65篇 |
1992年 | 94篇 |
1991年 | 71篇 |
1990年 | 56篇 |
1989年 | 58篇 |
1988年 | 54篇 |
1987年 | 40篇 |
1986年 | 32篇 |
1985年 | 40篇 |
1984年 | 24篇 |
1983年 | 22篇 |
1982年 | 17篇 |
1981年 | 23篇 |
1980年 | 18篇 |
1978年 | 15篇 |
1977年 | 12篇 |
1976年 | 7篇 |
1974年 | 10篇 |
1973年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
61.
David S. Gullion T. Elaine Adamson Malcolm S. M. Watts 《The Western journal of medicine》1983,138(4):582-588
The Professional Competence Assurance Program (PROCAP) is an individualized educational program that examines physicians'' performance in ambulatory practice. It uses medical record review to identify deficiencies in the care process that guides development of the educational intervention. Medical care is reassessed one year later. This program was used with 51 private practitioners to assess the care of 1,229 hypertensive patients. The educational program included a computer printout comparing one physician''s performance with that of peers, readings targeted to management problems, and a conference call or group seminar with an expert stressing issues relevant to each physician''s performance. Postintervention assessment showed that physicians prescribed beta-blockers (P<.01) and vasodilators (P<.01) more often. Improvement (P<.05) occurred in the control of diastolic blood pressure (≤90 mm of mercury) and in several other criteria. These results show that well-designed, individualized continuing medical education addressing specific deficiencies can change physicians'' performance and patients'' intermediate outcome. 相似文献
62.
A definite rise in plasma 11-hydroxycorticoid levels has been shown in eight patients with duodenal ulcer following the oral administration of carbenoxolone sodium. A similar rise was seen in one patient with sarcoidosis whose pituitary A.C.T.H. secretion had been acutely suppressed with dexamethasone. No such rise, however, was seen in three patients suffering from adrenal insufficiency. It is suggested that carbenoxolone acts directly on the adrenal cortex, causing an increased production of corticosteroids. 相似文献
63.
Terminal Disinfection in Hospitals with Quaternary Ammonium Compounds by Use of a Spray-Fog Technique 下载免费PDF全文
Spray-fogging of hospital rooms with a quarternary ammonium disinfectant was found to be an effective means of reducing the number of detectable airborne and surface bacteria. The level of bacterial contamination in hospital rooms was determined before and after fogging by means of the gravitational fallout method, the petri dish swab technique, and volumetric air-sampling procedures. Rooms vacated by patients infected with staphylococci, streptococci, pseudomonads, and salmonellae were tested and found to be effectively decontaminated of most of the detectable organisms by the fogging procedure. 相似文献
64.
65.
Previously existing methods for determining the pH limits for the growth of microorganisms have involved (1), the setting up of individual cultures, each having a specific pH; (2), the pH gradient plate technique devised by Sacks (1956) in which a continuous pH gradient is established in a Petri dish by means of a buffer system; and (3), the pH gradient plate technique of Zak (unpublished), in which a continuous pH gradient is established by means of an electric current. The discontinuous pH gradient technique described here provides a convenient method of determining the maximum and minimum pH at which a microorganism can grow. The technique can be used aerobically or anaerobically, and has a precision of about ± 0.1 pH unit. Data are given for several yeasts and forSerratia marcescens. In all cases, the organisms tested continued to metabolize at pH values beyond those representing the limits for growth, sometimes by as much as 0.5 pH unit. The results suggest that pH limits are unsuitable criteria in microbial classification. 相似文献
66.
67.
68.
S. K. Hira J. Kamanga G. J. Bhat C. Mwale G. Tembo N. Luo P. L. Perine 《BMJ (Clinical research ed.)》1989,299(6710):1250-1252
OBJECTIVE--To determine the occurrence of vertical transmission of HIV-I from women positive for the virus and the prognosis for their babies. DESIGN--Women presenting in labour were tested for HIV-I. Their newborn babies were also tested. Women positive for the virus were followed up with their babies for two years. SETTING--Teaching hospital in Lusaka, Zambia. SUBJECTS--1954 Women, of whom 227 were seropositive. Of 205 babies, 192 were positive for HIV-I. After birth 109 seropositive mothers and their babies and 40 seronegative mothers and their babies were available for follow up. MAIN OUTCOME MEASURES--Serological examination of mothers and their babies by western blotting. Birth weight and subsequent survival of babies. Women and babies were tested over two years for signs of seroconversion and symptoms of infection with HIV, AIDS related complex, and AIDS. RESULTS--Of the 109 babies born to seropositive mothers and available for follow up, 18 died before 8 months, 14 with clinical AIDS. Of the 91 remaining, 23 were seropositive at 8 months. By 24 months 23 of 86 surviving babies were seropositive, and a further five infected babies had died, four were terminally ill, 17 had AIDS related complex, and two had no symptoms. The overall rate of perinatal transmission was 42 out of 109 (39%). The overall mortality of infected children at 2 years was 19 out of 42 (44%). Before the age of 1 year infected children had pneumonia and recurrent coughs, thereafter symptoms included failure to thrive, recurrent diarrhoea and fever, pneumonia, candidiasis, and lymphodenopathy. All babies had received live attenuated vaccines before 8 months with no adverse affects. CONCLUSIONS--Vertical transmission from infected mothers to their babies is high in Zambia and prognosis is poor for the babies. Perinatal transmission and paediatric AIDS must be reduced, possibly by screening young women and counselling those positive for HIV-I against future pregnancy. 相似文献
69.
Elaine K. Perry Elizabeth Marshall Janet Kerwin Carthage J. Smith † Sabiha Jabeen Anthony V. Cheng Robert H. Perry† 《Journal of neurochemistry》1990,55(4):1454-1456
Senile dementia of Lewy body type is characterized clinically by a relatively acute onset of fluctuating memory loss and confusion, frequently accompanied by visual hallucinations. Neurochemical analyses of temporal cortex has revealed a distinction between hallucinating and nonhallucinating patients in both cholinergic and monaminergic transmitter activities. In contrast with the cholinergic enzyme choline acetyltransferase, which was more extensively reduced in hallucinating individuals, serotonergic S2 receptor binding and both dopamine and serotonin metabolites were significantly decreased in nonhallucinating cases. These results suggest that an imbalance between monaminergic and cholinergic transmitters is involved in hallucinogenesis in the human brain. 相似文献
70.
Virological survey of rhesus monkeys in China 总被引:1,自引:0,他引:1
A virological survey of rhesus monkeys captured in China for 13 viruses and/or antibodies was performed. Antigens used were SFV, SF40, HSV-1, Sa11, measles, vaccinia, epidemic or simian hemorrhagic fever, Langat, Kunming, poliomyelitis, HIV, SV41 and rubella. Monkeys were from Sichuan, Hunan, Guizhou, Yunnan and Guangxi provinces. Antibody was detected to all the listed viruses except HIV, SV41 and rubella. Both SFV and SV40 were recovered from monkeys, but H. simiae, LCM and coxsackieviruses were not. 相似文献