全文获取类型
收费全文 | 2832篇 |
免费 | 220篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 61篇 |
妇产科学 | 39篇 |
基础医学 | 367篇 |
口腔科学 | 42篇 |
临床医学 | 251篇 |
内科学 | 652篇 |
皮肤病学 | 29篇 |
神经病学 | 235篇 |
特种医学 | 166篇 |
外科学 | 546篇 |
综合类 | 63篇 |
预防医学 | 145篇 |
眼科学 | 56篇 |
药学 | 145篇 |
中国医学 | 12篇 |
肿瘤学 | 258篇 |
出版年
2023年 | 15篇 |
2022年 | 27篇 |
2021年 | 48篇 |
2020年 | 28篇 |
2019年 | 38篇 |
2018年 | 64篇 |
2017年 | 36篇 |
2016年 | 62篇 |
2015年 | 78篇 |
2014年 | 82篇 |
2013年 | 133篇 |
2012年 | 196篇 |
2011年 | 150篇 |
2010年 | 95篇 |
2009年 | 113篇 |
2008年 | 164篇 |
2007年 | 177篇 |
2006年 | 171篇 |
2005年 | 176篇 |
2004年 | 157篇 |
2003年 | 119篇 |
2002年 | 108篇 |
2001年 | 100篇 |
2000年 | 78篇 |
1999年 | 66篇 |
1998年 | 35篇 |
1997年 | 47篇 |
1996年 | 28篇 |
1995年 | 25篇 |
1994年 | 19篇 |
1993年 | 18篇 |
1992年 | 50篇 |
1991年 | 27篇 |
1990年 | 28篇 |
1989年 | 39篇 |
1988年 | 43篇 |
1987年 | 41篇 |
1986年 | 31篇 |
1985年 | 31篇 |
1984年 | 12篇 |
1983年 | 16篇 |
1982年 | 13篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1977年 | 9篇 |
1976年 | 14篇 |
1975年 | 10篇 |
1974年 | 8篇 |
1973年 | 7篇 |
1968年 | 6篇 |
排序方式: 共有3082条查询结果,搜索用时 15 毫秒
21.
Comparison of hospital staff performance when using desk top analysers for "near patient" testing. 总被引:1,自引:1,他引:1
下载免费PDF全文
![点击此处可从《Journal of clinical pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The quality and reliability of four desk top analysers were evaluated. In the context of an outpatient clinic, intensive care unit, and a mock up of a physician's office. Seventeen nurses, 14 physicians, and 12 medical office personnel took part in the study. The instruments and tests evaluated were Reflotron (glucose, cholesterol, triglycerides, gamma-glutamyl transferase), Seralyzer (creatinine, glucose, potassium, aspartate aminotransferase), Vision (glucose, (creatinine, glucose, potassium, aspartate aminotransferase), Vision (glucose, urea, cholesterol, triglycerides alkaline phosphatase, uric acid), and DT60 (sodium, potassium, glucose, amylase, uric acid and creatinine). Of the 320 tests performed on the Vision, only two differed by more than 10% between the specialist staff and other groups. For those performed on the Seralyzer, 95 of 254 results differed by more than 10%, 19 of 199 by more than 10% for the Reflotron, and 50 of 318 by more than 10% for the DT60. In general, the nurses were more adept at using the analysers than the physicians and medical office personnel. 相似文献
22.
Detection of multiple gene amplifications in glioblastoma multiforme using array-based comparative genomic hybridization 总被引:15,自引:0,他引:15
Hui AB Lo KW Yin XL Poon WS Ng HK 《Laboratory investigation; a journal of technical methods and pathology》2001,81(5):717-723
We have used a new method of genomic microarray to investigate amplification of oncogenes throughout the genome of glioblastoma multiforme (GBM). Array-based comparative genomic hybridization (array CGH) allows for simultaneous examination of 58 oncogenes/amplicons that are commonly amplified in various human cancers. Amplification of multiple oncogenes in human cancers can be rapidly determined in a single experiment. Tumor DNA and normal control DNA were labeled by nick translation with green- and red-tagged nucleotides, respectively. Instead of hybridizing to normal metaphase chromosomes in conventional comparative genomic hybridization (CGH), the probes of the mixed fluorescent labeled DNA were applied to genomic array templates comprised of P1, PAC, and BAC clones of 58 target oncogenes. The baseline for measuring deviations was established by performing a series of independent array CGH using test and reference DNA made from normal individuals. In the present study, we examined fourteen GBMs (seven cell lines and seven tumours) with CGH and array CGH to reveal the particular oncogenes associated with this cancer. High-level amplifications were identified on the oncogenes/amplicons CDK4, GLI, MYCN, MYC, MDM2, and PDGFRA. The highest frequencies of gains were detected on PIK3CA (64.3%), EGFR (57.1%), CSE1L (57.1%), NRAS (50%), MYCN (42.9%), FGR (35.7%), ESR (35.7%), PGY1 (35.7%), and D17S167 (35.7%). These genes are suggested to be involved in the GBM tumorigenesis. 相似文献
23.
Nickel-titanium (NiTi) shape memory alloys possess super-elasticity in addition to the well-known shape memory effect and are potentially suitable for orthopedic implants. However, a critical concern is the release of harmful Ni ions from the implants into the living tissues. We propose to enhance the corrosion resistance and other surface and biological properties of NiTi using carbon plasma immersion ion implantation and deposition (PIII&D). Our corrosion and simulated body fluid tests indicate that either an ion-mixed amorphous carbon coating fabricated by PIII&D or direct carbon PIII can drastically improve the corrosion resistance and block the out-diffusion of Ni from the materials. Our tribological tests show that the treated surfaces are mechanically more superior and cytotoxicity tests reveal that both sets of plasma-treated samples favor adhesion and proliferation of osteoblasts. 相似文献
24.
This paper describes the tragic case of a young woman who died of cancer of
the colon after successfully donating eggs to her younger sister. Although
there is no direct link between her operation and the subsequent
development of bowel carcinoma, this case imparts a feeling of unease when
seen in conjunction with other cases reported during the last few years. It
is a reminder that little is known of the long-term consequences of some
aspects of assisted conception. Women undergoing ovarian stimulation for
themselves or a matched recipient have the right to be advised, in an
agreed format, that there is some concern about unproven potential risks
from the stimulatory drugs. The safety of egg donors must assume priority
over all other considerations, including lack of donors or any moral
position. The recent decision by the Human Fertilisation and Embryology
Authority (HFEA) to withdraw any form of payment or recompense to egg
donors does not seem to us to be based on a balance of scientific advances,
patient needs and the ethics of gamete supply. They state that the
intention to withdraw payments was implicit in the 1990 Human Fertilisation
and Embryology (HFE) Act. However the Act was based on the Warnock report
made 6 years earlier. Even in 1990 ovum donation was uncommon and fertility
drugs had not yet caused any unease. The Act provided the HFEA with
discretionary powers to issue directions so that the future policies would
be consistent with any emerging new medical evidence. It is imperative that
the HFEA provide convincing evidence on how the current policy of payment
to donors harms society, donors or recipients, and how in the UK the new
policy will improve medical practice in assisted conception. Successful
pilot studies must precede the implementation of any new policy. Failure to
do this could cause irreversible harm to the practice of assisted
conception using donor gametes, which will ultimately be against the basic
aims of the 1990 HFE Act.
相似文献
25.
A single-chain antibody fragment (scFv) was constructed from a hybridoma antibody that binds to phosphorylcholine (PC) only when this hapten is presented in the form of the immunizing antigen (derived from Trichinella) but not when it is presented on other carriers (as found, for example, in pneumococcal capsules). The scFv derivative was found to lack this carrier specificity as it bound indiscriminately, but specifically, to the various PC-associated antigens, and exhibits a two-fold lower affinity (3.5x10(5)M(-1)) for nitrophenyl-PC than the native antibody. The findings suggest that the scFv combining site is different in fine structure from that of the native antibody. 相似文献
26.
27.
The resolving powers of the enforced smoothing and log-normal parametric estimation techniques in recovering ventilation/perfusion
ratio
distributions were evaluated using noisy inert gas elimination data simulated from hypothetical distribution functions representing
various degrees of heterogeneity. The resolving powers were assessed in terms of the statistical recoverabilities of the shunt,
dead space, modality, and modal moments characterizing the perfusion distribution. For all distributions tested, both modal
mean and shunt were estimated by either technique with sufficient accuracies. Modal dispersions (σ) were consistently overestimated
by up to 0.15 decade for narrow distributions, but the mean errors became negligible for σ greater than 0.2 decade. As compared
with the shunt, the dead space estimates were more variable and biased, probably due to their indirect estimation from the
perfusion distribution, which was imperfectly recovered. Both broad unimodal and widely separated bimodal or trimodal distributions
(σ>0.6 decade) were recovered as bimodal distributions of similar forms, so that detection of modality was difficult. The
recoveries by both techniques were comparable in most cases studied, except that parametric estimation generally tended to
be more sensitive to measurement errors and was computationally less efficient. These results provide a useful basis for the
interpretation of
distributions obtained from empirical inert gas data. 相似文献
28.
K.K.W. To C.C.Y. Yip C.Y.W. Lai C.K.H. Wong D.T.Y. Ho P.K.P. Pang A.C.K. Ng K.-H. Leung R.W.S. Poon K.-H. Chan V.C.C. Cheng I.F.N. Hung K.-Y. Yuen 《Clinical microbiology and infection》2019,25(3):372-378
Objectives
Automated point-of-care molecular assays have greatly shortened the turnaround time of respiratory virus testing. One of the major bottlenecks now lies at the specimen collection step, especially in a busy clinical setting. Saliva is a convenient specimen type that can be provided easily by adult patients. This study assessed the diagnostic validity, specimen collection time and cost associated with the use of saliva.Methods
This was a prospective diagnostic validity study comparing the detection rate of respiratory viruses between saliva and nasopharyngeal aspirate (NPA) among adult hospitalized patients using Xpert® Xpress Flu/RSV. The cost and time associated with the collection of saliva and nasopharyngeal specimens were also estimated.Results
Between July and October 2017, 214 patients were recruited. The overall agreement between saliva and NPA was 93.3% (196/210, κ 0.851, 95% CI 0.776–0.926). There was no significant difference in the detection rate of respiratory viruses between saliva and NPA (32.9% (69/210) versus 35.7% (75/210); p 0.146). The overall sensitivity and specificity were 90.8% (81.9%–96.2%) and 100% (97.3%–100%), respectively, for saliva, and were 96.1% (88.9%–99.2%) and 98.5% (94.7%–99.8%), respectively, for NPA. The time and cost associated with the collection of saliva were 2.26-fold and 2.59-fold lower, respectively, than those of NPA.Conclusions
Saliva specimens have high sensitivity and specificity in the detection of respiratory viruses by an automated multiplex Clinical Laboratory Improvement Amendments-waived point-of-care molecular assay when compared with those of NPA. The use of saliva also reduces the time and cost associated with specimen collection. 相似文献29.
Chronic Shigella flexneri infection preceding development of acquired immunodeficiency syndrome
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Shigella sp. is known to be an important cause of diarrhea in homosexual men, although chronic infection is infrequently recognized. We describe recurrent and relapsing symptomatic infection due to Shigella flexneri in a human immunodeficiency virus-infected homosexual man subsequently developed acquired immunodeficiency syndrome. Patients with acquired immunodeficiency syndrome may be prone to developing chronic shigellosis because of impaired intestinal cell-mediated immunity. 相似文献
30.
Near-patient testing. Quality of laboratory test results obtained by non-technical personnel in a decentralized setting 总被引:1,自引:0,他引:1
The authors evaluated the quality and reliability of four desktop analyzers in the outpatient clinic. Twenty-seven nontechnologists (NTs) participated in the study. These included nurses, physicians, and medical students. The instruments and tests evaluated were as follows: Reflotron (glucose, cholesterol, triglycerides, gamma-glutamyltransferase and urea); Seralyzer (creatinine, glucose, potassium, aspartate aminotransferase, and hemoglobin); Vision (glucose, urea, cholesterol, triglycerides, alkaline phosphatase, and uric acid); and DT60 (sodium, potassium, glucose, amylase, uric acid, bilirubin, and creatinine). For precision studies, low and high control material was used, and method comparison was done with methods in routine use in the laboratory. The range of coefficients of variation (CVs) for the analyzers with NTs was as follows: Reflotron: CV, 2.4-7.9%; Seralyzer CV, 1.4-18.7%; Vision: CV, 1.5-2.7%; DT60: CV, 2.5-46.8. The percentage results that is different by greater than 10% between the NTs and trained technologists was related to the complexicity of procedure for each analyzer and was the lowest for the Vision analyzer and greatest for the Seralyzer. 相似文献