全文获取类型
收费全文 | 1589篇 |
免费 | 139篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 103篇 |
妇产科学 | 38篇 |
基础医学 | 203篇 |
口腔科学 | 27篇 |
临床医学 | 196篇 |
内科学 | 290篇 |
皮肤病学 | 29篇 |
神经病学 | 133篇 |
特种医学 | 181篇 |
外科学 | 159篇 |
综合类 | 21篇 |
预防医学 | 122篇 |
眼科学 | 11篇 |
药学 | 126篇 |
肿瘤学 | 118篇 |
出版年
2021年 | 14篇 |
2020年 | 9篇 |
2019年 | 17篇 |
2018年 | 31篇 |
2017年 | 16篇 |
2016年 | 13篇 |
2015年 | 28篇 |
2014年 | 26篇 |
2013年 | 53篇 |
2012年 | 45篇 |
2011年 | 53篇 |
2010年 | 58篇 |
2009年 | 63篇 |
2008年 | 56篇 |
2007年 | 83篇 |
2006年 | 49篇 |
2005年 | 64篇 |
2004年 | 57篇 |
2003年 | 66篇 |
2002年 | 75篇 |
2001年 | 66篇 |
2000年 | 39篇 |
1999年 | 41篇 |
1998年 | 59篇 |
1997年 | 71篇 |
1996年 | 63篇 |
1995年 | 54篇 |
1994年 | 56篇 |
1993年 | 32篇 |
1992年 | 20篇 |
1991年 | 37篇 |
1990年 | 32篇 |
1989年 | 36篇 |
1988年 | 29篇 |
1987年 | 27篇 |
1986年 | 25篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 14篇 |
1982年 | 18篇 |
1981年 | 13篇 |
1980年 | 13篇 |
1979年 | 15篇 |
1978年 | 12篇 |
1977年 | 15篇 |
1976年 | 10篇 |
1974年 | 7篇 |
1972年 | 9篇 |
1971年 | 6篇 |
1969年 | 6篇 |
排序方式: 共有1766条查询结果,搜索用时 15 毫秒
991.
Multiple cultural variables have effects on the psychobiology and behavioral manifestations of illness, as do patient and physician perceptions of illness. The interaction among these variables is at the heart of clinical psychiatry. This case of a Vietnamese man with selective mutism underscores the relevance of the 'cultures' of medicine, psychiatry, and war and trauma on the manifestations of illness and illness perceptions by patient and physician. The discussion focuses on how these cultures interact and play a crucial role in formulating diagnosis and treatment planning. Suggestions are given for shifts in medical education that will encourage relevant cultural paradigms to make their way into educational and clinical systems, which in turn should improve cultural competence in clinical psychiatry. 相似文献
992.
Bodiwala D Luscombe CJ French ME Liu S Saxby MF Jones PW Ramachandran S Fryer AA Strange RC 《Carcinogenesis》2003,24(4):711-717
Recent studies have proposed that exposure to ultraviolet radiation (UVR) protects against development of some internal cancers including that in prostate. This effect may be mediated by UVR-induced cutaneous synthesis of vitamin D. It is also proposed that ability to pigment in response to UVR will influence susceptibility to prostate cancer through its effects on vitamin D synthesis. We wished to determine first, whether ability to pigment, as assessed by skin type, influences the extent of exposure to UVR, secondly, whether skin type is associated with prostate cancer susceptibility and thirdly, whether such an effect is mediated by the extent of UVR exposure. We studied 453 prostatic adenocarcinoma and 312 benign prostatic hypertrophy (BPH) patients using a validated questionnaire to assess two parameters of exposure; months of cumulative exposure per year and adult sunbathing score. We used analysis of variance to show that cancer cases with sun-sensitive skin (skin type 1) had lower cumulative exposure per year (P = 0.014) and sunbathing scores (P < 0.0001) than those with type 4, possibly because of a tendency to avoid exposure. Further, cumulative exposure per year and sunbathing score were significantly lower in cancer compared with BPH patients (P < 0.001 and P < 0.001, respectively). While the proportion of subjects with skin types 1 and 2 was lower in cancer than BPH patients, these were not significantly different (logistic regression analysis, skin type 1 versus type 4; P = 0.11). We used recursive partitioning to determine if skin type influenced susceptibility to prostate cancer in subgroups stratified by exposure. Analysis of the data showed that in men with low sunbathing scores, skin type 1 conferred protection compared with skin types 2-4 (OR = 4.78, 95% CI 3.01-8.25, P < 0.0009). These findings indicate that susceptibility to prostate cancer is in part determined by extent of exposure to UVR and that ability to pigment mediates this effect. 相似文献
993.
Kaufman DB Leventhal JR Koffron A Gheorghiade M Elliott MD Parker MA Abecassis MM Fryer JP Stuart FP 《Surgery》2000,128(4):726-737
BACKGROUND: In the past, enteric drainage or the omission of induction immunotherapy has been shown to be predictive of suboptimal outcomes of simultaneous pancreas-kidney (SPK) transplantation. We have reassessed the need for bladder drainage and induction immunotherapy to optimize the outcome of SPK transplantation. METHODS: One hundred consecutive recipients of SPK transplants who received mycophenolate mofetil and tacrolimus immunosuppression were studied. The first 50 recipients had bladder-drained pancreas allografts and received induction immunotherapy. The results were compared with the next 50 recipients who had enteric-drained pancreas allografts, which included a subgroup (n = 17 patients) who were randomized to receive no induction immunotherapy. RESULTS: The 1-year actuarial patient, kidney, and pancreas survival rates in the bladder-drainage group were 98.0%, 94.0%, and 94.0%, respectively. The 1-year actuarial patient, kidney, and pancreas survival rates in the enteric-drainage group were 96.8%, 96.8%, and 89.4%, respectively. In the enteric-drainage group, the incidence of rejection at 1 year was 6.1% in recipients who received induction therapy versus 23.5% in recipients who did not receive induction therapy. The average number of readmissions per recipient was 1.8 in the bladder-drainage group versus 0.9 in the enteric-drainage group. CONCLUSIONS: Primary enteric drainage of the pancreas allograft in recipients of SPK transplantation is the preferred surgical technique in the tacrolimus/mycophenolate mofetil era. 相似文献
994.
Fleming JS Goatman KA Julyan PJ Boivin CM Wilson MJ Barber RW Bird NJ Fryer TD 《Nuclear medicine communications》2000,21(12):1095-1102
The development of coincidence positron imaging using a gamma camera should significantly increase PET utilization. This study has compared the performance of three such systems with each other and with an equivalent single photon emission computed tomography (SPECT) measurement. A Carlson phantom, which consisted of a 20 cm diameter cylinder containing areas of uniform activity, hot lesions, cold lesions and orthogonal alternate hot and cold lines, was filled with an activity of 18F chosen to try and best exploit each camera and imaged for a fixed time (27 min). The image quality of 9 mm thick slices in each section of the phantom was compared visually. Several image quality parameters were also compared including line source resolution and noise equivalent count rate. There were considerable differences in PET image quality between the three cameras but all were at least as good as the SPECT image. The full width at half maximum (FWHM) resolution of all systems was similar (approximately 4.5 mm) but the maximum noise equivalent count rates in a 20 cm cylinder were significantly different (6.3, 2.6 and 1.6 kcps) (where cps is counts per second) and correlated with the phantom image quality. 相似文献
995.
996.
Todd A Florin G Edgar Fryer Thomas Miyoshi Michael Weitzman Ann C Mertens Melissa M Hudson Charles A Sklar Karen Emmons Andrea Hinkle John Whitton Marilyn Stovall Leslie L Robison Kevin C Oeffinger 《Cancer epidemiology, biomarkers & prevention》2007,16(7):1356-1363
PURPOSE: To determine if adult survivors of childhood acute lymphoblastic leukemia (ALL) are less active (and more inactive) than the general population and to identify modifying factors. PATIENTS AND METHODS: Physical activity was assessed by self-report in 2,648 adult survivors of the Childhood Cancer Survivor Study. Participants in the Behavioral Risk Factor Surveillance System (BRFSS) survey administered through the Centers for Disease Control and Prevention (CDC) were used as a comparison group. RESULTS: Survivors had a mean age of 28.7 years (range, 18.0-44.0 years) and were a mean of 23.1 years from their cancer diagnosis (range, 16.0-33.8 years). In multivariate models, ALL survivors were more likely to not meet CDC recommendations for physical activity [odds ratio (OR), 1.44; 95% confidence interval (95% CI), 1.32-1.57] and more likely to be inactive (OR, 1.74; 95% CI, 1.56-1.94) in comparison with the BRFSS general population. Survivors treated with >20-Gy cranial radiotherapy were at particular risk. Compared with BRFSS participants and adjusted for age, race, and ethnicity, survivors were more likely to not meet CDC recommendations (females: OR, 2.07, 95% CI, 1.67-2.56; males: OR, 1.43, 95% CI, 1.16-1.76) and more likely to be inactive (females: OR, 1.86; 95% CI, 1.50-2.31; males: OR, 1.84; 95% CI, 1.45-2.32). CONCLUSIONS: Long-term survivors of childhood ALL are less likely to meet physical activity recommendations and more likely to report no leisure-time physical activity in the past month. This level of inactivity likely further increases their risk of cardiovascular disease, osteoporosis, and all-cause mortality. 相似文献
997.
Papillomas at high risk for malignant progression arising both early and late during two-stage carcinogenesis in SENCAR mice 总被引:1,自引:1,他引:1
DuBowski A; Johnston DA; Rupp T; Beltran L; Conti CJ; DiGiovanni J 《Carcinogenesis》1998,19(6):1141-1147
The current study was designed to further establish that most papillomas
produced in SENCAR mice during two-stage skin carcinogenesis are, in fact,
premalignant lesions and to specifically determine the malignant conversion
potential of papillomas that arise at different times during the
carcinogenesis process. A method was established to physically map and
monitor the lifespan of all papillomas produced in SENCAR mice during the
course of an initiation-promotion experiment using DMBA as the initiator
and 12-O-tetradecanoylphorbol-13-acetate (TPA) as the promoter. The results
from these experiments showed that in groups of mice initiated with either
0.5 or 2.0 microg DMBA, long- term (60 weeks) treatment with TPA yielded a
significantly higher number of SCCs compared to short-term treatment (7
weeks). Papillomas that emerged after 11 weeks and thereafter in all
treatment groups had the ability to progress to SCCs. The median conversion
time for all papillomas in all groups was 26 weeks. When corrected for
median conversion time, papillomas that emerged in week 11 and thereafter
in all treatment groups had similar or greater conversion ratios compared
to those that emerged within the first 10 weeks. Interestingly, the median
conversion time was significantly shorter (18 versus 27 weeks,
respectively; P<0.0002) for papillomas that emerged in week 11 and
thereafter compared to those that emerged at or prior to 10 weeks for all
groups. The data in this study demonstrate that papillomas arising
throughout a two-stage carcinogenesis protocol in SENCAR mice progress to
SCCs. Many papillomas that arise later in two-stage carcinogenesis
protocols do not have sufficient time to allow for conversion and should be
excluded from the analyses. Furthermore, another novel finding of the
current study was the observation that papillomas arising later in the
two-stage protocol (>11 weeks) progressed to SCCs at a faster rate than
those that arose earliest in the protocol.
相似文献
998.
Stern MC; Gimenez-Conti IB; Budunova I; Coghlan L; Fischer SM; DiGiovanni J; Slaga TJ; Conti CJ 《Carcinogenesis》1998,19(1):125-132
The SENCAR stock of mice has proved to be a useful model in dissecting out
the multistage nature as well as the critical mechanisms involved in skin
tumorigenesis. This outbred stock was selectively bred to be susceptible to
initiation with 7,12-dimethylbenz[a]anthracene (DMBA) and promotion with
12-O-tetradecanoylphorbol-13-acetate (TPA). In order to obtain mice more
suitable for genetic analyses of tumor susceptibility and tissue
transplantation studies, several inbred lines of mice were derived from the
SENCAR stock. One of these lines, the SSIN mice, has a higher
susceptibility to tumor promotion compared to the SENCAR stock but is very
resistant to tumor progression. On the other hand, the SENCAR B/Pt mice,
derived also from the outbred stock, not only have a tumor promotion
susceptibility almost identical to the SSIN mice, but they also have a high
susceptibility to tumor progression. In order to understand the nature of
the phenotypic differences between these two inbred lines we have
characterized them using several parameters and markers that are associated
with the progression of papillomas to squamous cell carcinoma (SCC). In
this sense we analysed the tumor multiplicity and SCC incidence, and the
expression of markers of progression and cell cycle related proteins in
papillomas derived from both strains. Our results showed that while both
strains have a similar papilloma multiplicity and incidence the SENCAR B/Pt
mice have 67% incidence of SCC, compared to 0% in the SSIN. SENCAR B/Pt
papillomas at 30 weeks of promotion have a higher and aberrant expression
of K13, and loss of connexin 26. TGF-beta1 was found to be over-expressed
in the suprabasal and superficial cells in the SENCAR B/Pt papillomas,
while it was only expressed in the superficial cell layer in those derived
from SSIN. The SENCAR B/Pt papillomas also showed an enlarged proliferative
compartment with overexpression of cyclin D1 and PCNA as seen by
immunohistochemistry and Western blot.
相似文献
999.
OBJECTIVE--To identify children suffering morbidity from excessive intake of energy from fluids. DESIGN--Prospective enrolment of outpatients in a supervised reduction of energy rich fluid intake. SETTING--Outpatient paediatric clinic. SUBJECTS--Eight children (four boys, mean age 20.8 months, mean duration of symptoms seven months) who were referred with non-specific symptoms such as poor appetite, poor behaviour at mealtimes, poor weight gain, and loose stools. RESULTS--All children were able to reduce their intake of energy rich fluids, as prescribed. All children demonstrated an improvement in symptoms and an increase in weight. CONCLUSIONS--A careful dietary history, which includes documentation of fluid intake may identify children whose intake of high energy drinks may be excessive. The pathogenesis, symptoms, and response to treatment of these patients are consistent enough to be regarded as a distinct clinical entity: the 'squash drinking syndrome'. 相似文献
1000.
Internationally, 20th century medical education concentrated on equipping new graduates with technical skills and pushing the frontiers of technological sciences to extend and enhance life in ways unimaginable in previous decades. In the 21st century, health services are expected to be characterized not by the "fix-up-when-things-go-wrong" type of care that 20th century physicians have become so good at, but by preventive care that can obviate much of the need for these fix-up services. Enabling doctors to deal with the different health care needs of future patients will require a values shift in medical education. The United States leads the world in per capita health care expenditure yet trails in many important measures of health status. It epitomizes many elements of both the good and the bad in current medical education that may be less obvious in other countries that are less wealthy, less technologically oriented, and less committed to individual freedoms. In this paper we use the US as a case study to argue the need for a fundamental shift in values away from the 20th century emphasis on disease, specialization and treatment, and towards health, generalization and prevention. We draw on data from the National Ambulatory Medical Care Survey to compare roles of primary care physicians and other office-based medical specialties in delivering preventive health care. We also estimate the cost of providing preventive care in terms of physician time. Finally, we contemplate how medical education values must change in the US and other countries if 21st century physicians are to be prepared to meet the health care needs of their communities. 相似文献