全文获取类型
收费全文 | 3081篇 |
免费 | 210篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 147篇 |
妇产科学 | 112篇 |
基础医学 | 523篇 |
口腔科学 | 49篇 |
临床医学 | 305篇 |
内科学 | 678篇 |
皮肤病学 | 57篇 |
神经病学 | 148篇 |
特种医学 | 170篇 |
外国民族医学 | 5篇 |
外科学 | 324篇 |
综合类 | 156篇 |
预防医学 | 205篇 |
眼科学 | 55篇 |
药学 | 135篇 |
1篇 | |
中国医学 | 74篇 |
肿瘤学 | 122篇 |
出版年
2021年 | 30篇 |
2018年 | 31篇 |
2017年 | 38篇 |
2016年 | 28篇 |
2015年 | 48篇 |
2014年 | 62篇 |
2013年 | 68篇 |
2012年 | 103篇 |
2011年 | 93篇 |
2010年 | 88篇 |
2009年 | 73篇 |
2008年 | 107篇 |
2007年 | 86篇 |
2006年 | 107篇 |
2005年 | 66篇 |
2004年 | 61篇 |
2003年 | 48篇 |
2002年 | 36篇 |
2001年 | 44篇 |
2000年 | 39篇 |
1999年 | 45篇 |
1998年 | 53篇 |
1997年 | 58篇 |
1996年 | 59篇 |
1995年 | 58篇 |
1994年 | 66篇 |
1993年 | 43篇 |
1992年 | 43篇 |
1991年 | 36篇 |
1990年 | 26篇 |
1989年 | 59篇 |
1988年 | 57篇 |
1987年 | 53篇 |
1986年 | 54篇 |
1985年 | 51篇 |
1984年 | 32篇 |
1983年 | 35篇 |
1981年 | 37篇 |
1980年 | 27篇 |
1959年 | 36篇 |
1958年 | 63篇 |
1957年 | 87篇 |
1956年 | 45篇 |
1955年 | 75篇 |
1954年 | 67篇 |
1929年 | 24篇 |
1928年 | 27篇 |
1927年 | 30篇 |
1926年 | 32篇 |
1925年 | 24篇 |
排序方式: 共有3308条查询结果,搜索用时 15 毫秒
31.
Fatalities among British Columbia fallers and buckers 1981-7 总被引:1,自引:0,他引:1
D A Salisbury R Brubaker C Hertzman G R Loeb 《Canadian journal of public health. Revue canadienne de santé publique》1991,82(1):32-37
In Canada, the forest industry has the highest rate of lost time injury (161 per thousand workers in 1986) and has the highest fatality rate (1.04 per thousand workers in 1986) of all industries. A retrospective case series of fatal accidents occurring among those employed as fallers or buckers in the British Columbia Forest Industry was studied. 87 cases were found and the files of the provincial coroner were accessed to provide data on these accidents. Due to a lack of denominator data, no risk factors could be identified by several hypotheses for future research were developed. These included: the possibility that lack of work experience and young age may play a role in these accidents, the observation that there are "peaks of incidence" just before noon, on Mondays and Thursdays and in January. There was also the surprising finding of the lack of toxicological evidence indicating impairment of any of these workers. Future directions for research are discussed. 相似文献
32.
The involvement of the proliferating cell nuclear antigen (PCNA) in the
process of DNA repair induced by alkylating agents or by oxidative damage
was investigated in human quiescent fibroblasts by immunofluorescence and
flow cytometry. Transition from soluble to the DNA-bound form of PCNA, was
taken as the parameter to determine its involvement in repair DNA
synthesis. Treatment with the alkylating agents methylmethane sulfonate and
N-methyl-N'-nitro-N-nitrosoguanidine resulted in the rapid and
dose-dependent increase in the nuclear binding of PCNA. Similar results
were obtained with compounds such as hydrogen peroxide or tert-butyl
hydroperoxide, which are known to induce oxidative DNA damage. Tert-butyl
hydroperoxide may also generate malondialdehyde through a reaction of lipid
peroxidation. This mutagenic and carcinogenic product has been previously
shown to form adducts with DNA. Therefore, the possibility that tert-butyl
hydroperoxide could induce DNA damage through this pathway was investigated
by incubating cells directly in the presence of malondialdehyde. Such
treatment resulted in an increase in immunofluorescence associated with
nuclear-bound PCNA. The ability of oxidative and alkylating agents to
induce the nuclear binding of PCNA was also assessed in proliferating
cells. In these conditions, treatment with hydrogen peroxide or
methylmethane sulfonate, resulted in an increase in nuclear-bound PCNA in
the G1 and in the G2 + M compartments, but not in S phase. At longer times
after treatment, PCNA immunostaining was reduced to basal levels, while an
increase in nuclear binding of p21(waf1/cip1) protein was found in
concomitance with cell-cycle arrest. These results indicate that agents
inducing DNA base alterations in vivo, promote the nuclear binding of PCNA.
These lines of evidence support the role of a PCNA-dependent reaction in
the base excision repair system.
相似文献
33.
Hansen LA; Malarkey DE; Wilkinson JE; Rosenberg M; Woychik RE; Tennant RW 《Carcinogenesis》1998,19(10):1837-1845
We previously reported that papillomas can arise from the follicular
epithelium of v-Ha-ras transgenic TGxAC mice. Since the viable-yellow
mutation (A(vy)) of the mouse agouti gene which regulates coat color
pigmentation by acting within the micro-environment of the hair follicle
has been shown to function as a tumor promoter in the liver, we
hypothesized that it may also play a role in TGxAC skin tumorigenesis.
Endogenous agouti protein product was detected in the outer root sheath of
anagen hair follicles following plucking of the hair shaft, but not in the
interfollicular epithelium, in TGxAC mice on an FVB/N genetic background.
It was also detected in papillomas from these mice produced by
12-O-tetradecanoylphorbol-13-acetate (TPA) treatment or plucking.
Expression of the A(vy) allele in the v-Ha-ras transgenic TGxAC mouse line
results in an approximately 2-fold increase in papilloma development
compared with controls which did not carry the A(vy) allele following
twice-weekly treatment with 1.25, 2.5 or 5.0 microg TPA. In addition,
TPA-treated, papilloma-bearing F1 mice which carried the A(vy) allele, but
not F1 mice which did not carry the A(vy) allele, exhibited a syndrome of
humoral hypercalcemia mediated by parathyroid hormone-related protein
(PTHrP) that led to weight loss, hypercalcemia and hypophosphatemia. Thus,
we conclude that the A(vy) allele can influence the development of skin
tumors and PTHrP-mediated humoral hypercalcemia in v-Ha-ras transgenic
TGxAC mice.
相似文献
34.
Non-invasive detection of fecal protein kinase C betaII and zeta messenger RNA: putative biomarkers for colon cancer 总被引:2,自引:0,他引:2
Davidson LA; Aymond CM; Jiang YH; Turner ND; Lupton JR; Chapkin RS 《Carcinogenesis》1998,19(2):253-257
We have developed a non-invasive method utilizing feces, containing
sloughed colonocytes, as a sensitive technique for detecting diagnostic
colonic biomarkers. In this study, we used the rat colon carcinogenesis
model to determine if changes in fecal protein kinase C (PKC) expression
have predictive value in monitoring the neoplastic process. Weanling rats
were injected with saline or azoxymethane (AOM) and 36 weeks later fecal
samples and mucosa were collected, poly A+ RNA isolated, and quantitative
RT-PCR performed using primers to PKC betaII and zeta. Fecal PKC betaII and
zeta mRNA levels were altered by the presence of a tumor, with
tumor-bearing animals having a 3-fold higher (P < 0.05) PKC betaII
expression as compared with animals without tumors. In addition,
AOM-injection increased mucosal PKC betaII mRNA expression compared with
saline controls. No effect of tumor incidence on mucosal PKC betaII
expression was observed. In contrast, fecal PKC zeta expression was
2.5-fold lower (P < 0.05) in animals injected with azoxymethane versus
saline. Since tumor incidence exerts a reciprocal effect on fecal PKC
betaII and zeta mRNA expression, data were also expressed as the ratio
between PKC betaII and zeta. The isozyme ratio was strongly related to
tumor incidence, i.e. ratio for animals with tumors was 2.18 +/- 1.25,
animals without tumors was 0.50 +/- 0.16, P = 0.025. We demonstrate that
the expression of fecal PKC betaII and zeta may serve as a noninvasive
marker for development of colon tumors. A sensitive technique for the
detection of colon cancer is of importance since early diagnosis can
substantially reduce mortality.
相似文献
35.
宫颈病变液基细胞学筛查与组织病理学对照观察 总被引:5,自引:1,他引:5
目的 探讨液基薄层细胞学(ThinPrepCytologyTest, TCT)技术在妇科门诊人群宫颈病变筛查的准确性。方法 回顾性分析10 980例TCT,与组织学对比观察。结果 TCTLSIL以上阳性率45. 7% ( 373 /817),组织学检查阳性率50. 1% ( 409 /817 ),两者统计学比较无显著性差异(P>0. 05 )。TCT诊断符合率LSIL75. 8% (191 /252),HSIL98. 1% (101 /103),SCC90. 9% (10 /11),AC85. 7% (6 /7)。鳞状上皮内病变诊断符合率HSIL与LSIL统计学比较有显著性差异(P<0. 01)。结论 液基细胞学检查是宫颈癌早期筛查的有效手段,加强制片技术及诊断质量控制对提高诊断的准确性有重要意义。 相似文献
36.
Allison J McGeer Wayne Lee Mark Loeb Andrew E Simor Margaret McArthur Karen Green Jonathan Hayfron Benjamin Charles Gardner 《Infection control and hospital epidemiology》2004,25(11):955-961
BACKGROUND AND OBJECTIVES: Antiviral prophylaxis is recommended for the control of institutional influenza A outbreaks. In long-term-care institutions other than nursing homes, neither the seriousness of influenza nor the risks and benefits of antiviral prophylaxis is clearly understood. We studied the severity of illness due to influenza among adults residing in a center for the developmentally disabled and assessed adverse reactions to amantadine and oseltamivir prophylaxis. METHODS: Data were collected from the charts of consenting residents. Complications of upper respiratory tract illness were recorded. Potential adverse events were documented during amantadine and oseltamivir therapy, and during a baseline period with neither medication. RESULTS: The median age of the 287 participants was 46.4 years. Only 15 (5%) were older than 65 years, and 69 (24%) had chronic underlying medical illness placing them at high risk for influenza. Of the 122 residents with an upper respiratory tract infection, 16 (13%) developed pneumonia, 12 (9.8%) were hospitalized, and 5 (4%) died. Twenty-eight (25%) of 112 residents had an adverse neurologic event while receiving amantadine prophylaxis, compared with 3 (2.7%) receiving no antiviral medication and 5 (4.5%) receiving oseltamivir (P < .001). Sixteen percent of the residents discontinued amantadine due to adverse events; in contrast, adverse events were identified in 2.9% of the residents prescribed oseltamivir, and none discontinued therapy. CONCLUSIONS: Viral respiratory tract infections are associated with a high risk of complications in this population. The rate of adverse neurologic events associated with amantadine was significantly higher than that associated with oseltamivir. 相似文献
37.
38.
Erin Jesse Wade Muncey Daniel Harris Kimberly Tay Tyler Kim Danly Omil-Lima Ilaha Isali Aram Loeb Nannan Thirumavalavan 《Canadian Urological Association journal》2022,16(5):E278
IntroductionProcedural specialties are at higher risk for malpractice claims than non-procedural specialties. Previous studies have examined common damages and malpractice lawsuits resulting from specific procedures. Our goal was to analyze urological interventions that led to sexual dysfunction (SD) claims.MethodsThe Casetext legal research platform was queried using search terms for medical malpractice and common men’s health procedures between 1993 and 2020. In total, 236 cases were found, and 21 cases met the inclusion criteria: malpractice cases against a urologist or urology group, clearly stated legal outcome, and allegation of sexual dysfunction from an intervention that directly caused damages.ResultsA total of 42 damages were cited in 21 lawsuits. The top three damages claimed were erectile dysfunction (ED) (14/42, 33.3%), genital pain syndrome (7/42, 16.7%), and urinary incontinence (5/42, 11.9%). The most commonly cited treatments were urinary catheter placement or removal (3/21, 14.3%), robotic-assisted laparoscopic radical prostatectomy (RALP) (3/21, 14.3%), circumcision (3/21, 14.3%), and penile implant (3/21, 14.3%). In 19 of 21 suits (90.4%), the outcome favored the defendant. Two cases favored the plaintiff: penile implant (failure to prove the patient was permanently, organically impotent prior to the procedure; missed urethral injury at time of surgery, $300 000) and vasectomy (damage to vasculature resulting in loss of testicle, $300 000).ConclusionsMost suspected malpractice cases resulting in SD favored the defendant urologist. Interestingly, urinary catheter placement is as likely to result in litigation as other operative interventions, such as RALP, inflatable penile prosthesis, and circumcision. It is possible that thorough preoperative counselling and increased responsiveness to patients’ postoperative concerns may have avoided litigation in several cases. 相似文献
39.
Childhood Lyme arthritis: experience in an endemic area 总被引:4,自引:0,他引:4
A H Eichenfield D P Goldsmith J L Benach A H Ross F X Loeb R A Doughty B H Athreya 《The Journal of pediatrics》1986,109(5):753-758
We report 25 children with oligoarticular arthritis associated with Lyme disease. There were 16 boys (male/female ratio 1.8:1); ages ranged from 2 to 15 years. Thirteen (52%) children had no history of erythema chronicum migrans or other rash. Thirteen had temperatures as high as 41 degrees C for up to 2 months before the onset of arthritis. Twelve recalled definite tick bites. Ten (40%) children, of whom seven had no history of rash, were hospitalized for presumed septic arthritis. Another four had diagnoses of pauciarticular juvenile rheumatoid arthritis for as long as 3 years. Seven patients had less acute, recurrent episodes of synovitis. Two children had seventh nerve palsies 2 months before onset of arthritis. All patients had antibodies to the Lyme spirochete. In 14 patients, synovial fluid white blood cell counts ranged from 180 to 97,700/mm3 (greater than or equal to 76% polymorphonuclear leukocytes). Antibiotic therapy was effective in all patients; in 13, orally administered therapy alone resulted in elimination of synovitis and recurrent attacks. Lyme arthritis may be confused with acute bacterial septic arthritis or recurrent "pauciarticular juvenile rheumatoid arthritis," particularly when there is no history of erythema chronicum migrans. 相似文献
40.
奇乳海参中两个具有抗真菌活性的三萜皂苷 总被引:2,自引:0,他引:2
目的:研究奇乳海参体内的化学成分,寻找结构新颖具有抗真菌活性的三萜皂苷类成分。方法:应用多种色谱分离技术对奇乳海参体内的化学成分进行分离纯化,根据化合物的理化性质,波谱数据及化学方法鉴定其结构。结果:分离得到2个三萜皂苷化合物,分别为axilogoside A(1)和holothurin B(2),并对其抗真菌活性进行了研究(4≤MIC80≤16μg·mL^-1)。结论:化合物1为一新的三萜皂苷化舍物,化合物2为首次从奇乳海参中分离得到,它们均显示一定的抗真菌活性。 相似文献