全文获取类型
收费全文 | 1846篇 |
免费 | 180篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 101篇 |
妇产科学 | 38篇 |
基础医学 | 241篇 |
口腔科学 | 67篇 |
临床医学 | 216篇 |
内科学 | 363篇 |
皮肤病学 | 26篇 |
神经病学 | 133篇 |
特种医学 | 149篇 |
外科学 | 249篇 |
综合类 | 75篇 |
预防医学 | 152篇 |
眼科学 | 40篇 |
药学 | 65篇 |
中国医学 | 1篇 |
肿瘤学 | 100篇 |
出版年
2022年 | 16篇 |
2021年 | 40篇 |
2020年 | 23篇 |
2019年 | 47篇 |
2018年 | 71篇 |
2017年 | 43篇 |
2016年 | 50篇 |
2015年 | 53篇 |
2014年 | 60篇 |
2013年 | 98篇 |
2012年 | 80篇 |
2011年 | 57篇 |
2010年 | 76篇 |
2009年 | 78篇 |
2008年 | 49篇 |
2007年 | 80篇 |
2006年 | 57篇 |
2005年 | 71篇 |
2004年 | 38篇 |
2003年 | 51篇 |
2002年 | 32篇 |
2001年 | 38篇 |
2000年 | 29篇 |
1999年 | 35篇 |
1998年 | 54篇 |
1997年 | 50篇 |
1996年 | 54篇 |
1995年 | 51篇 |
1994年 | 26篇 |
1993年 | 37篇 |
1992年 | 23篇 |
1991年 | 21篇 |
1990年 | 17篇 |
1989年 | 34篇 |
1988年 | 28篇 |
1987年 | 27篇 |
1986年 | 30篇 |
1985年 | 28篇 |
1984年 | 18篇 |
1983年 | 29篇 |
1982年 | 12篇 |
1981年 | 22篇 |
1980年 | 15篇 |
1979年 | 18篇 |
1978年 | 12篇 |
1977年 | 20篇 |
1976年 | 16篇 |
1975年 | 14篇 |
1973年 | 18篇 |
1972年 | 16篇 |
排序方式: 共有2034条查询结果,搜索用时 0 毫秒
21.
22.
Esaki Muthu Shankar Ramachandran Vignesh Kailapuri G Murugavel Pachamuthu Balakrishnan Ramalingam Sekar Charmaine AC Lloyd Suniti Solomon Nagalingeswaran Kumarasamy 《AIDS research and therapy》2007,4(1):1-7
Background
CD4+ T lymphocyte (CD4) cell count testing is the standard method for determining eligibility for antiretroviral therapy (ART), but is not widely available in sub-Saharan Africa. Total lymphocyte counts (TLCs) have not proven sufficiently accurate in identifying subjects with low CD4 counts. We developed clinical algorithms using TLCs, hemoglobin (Hb), and body mass index (BMI) to identify patients who require ART. 相似文献23.
Comparison of methods for identifying resistant herpes simplex virus and measuring antiviral susceptibility. 总被引:1,自引:0,他引:1
Robert T Sarisky Paul Crosson Rachel Cano Matthew R Quail Tammy T Nguyen Robert J Wittrock Teresa H Bacon Stephen L Sacks Laure Caspers-Velu Richard L Hodinka Jeffry J Leary 《Journal of clinical virology》2002,23(3):191-200
BACKGROUND: A number of in vitro assays are used to determine susceptibility of HSV to antiviral agents, but results from these in vitro assays do not necessarily correlate with treatment outcome. OBJECTIVES: A method with improved capability for identifying an isolate as acyclovir (ACV) or penciclovir (PCV) resistant when resistance is borderline could greatly improve the management of HSV disease. STUDY DESIGN: A comparative evaluation of four in vitro assays, plaque reduction (PRA), DNA hybridization, plating efficiency (PEA) and plaque autoradiography (PAR) was performed to accurately identify and measure resistance of a TK-altered clinical HSV isolate (HSV-1 N4) from a patient who was non-responsive to ACV treatment. Two established criteria for the prediction of antiviral resistance, IC(50)> or =2.0 microg/ml or an IC(50) greater than 10x above a sensitive virus IC(50), as well as testing in human (MRC-5) and nonhuman (Vero and CV-1 monkey kidney) cell lines were evaluated. RESULTS: The PRA and DNA hybridization assays accurately identified HSV-1 N4 as ACV(r) in human cells when using the 10x above sensitive virus IC(50) resistance criterion. Moreover, the PEA and PAR assays failed to classify HSV-1 N4 as drug resistant and indicate that these technologies alone are inadequate for identifying resistant virus. CONCLUSIONS: The data presented herein indicate that the PRA and DNA hybridization assays most accurately identified an otherwise borderline-resistant isolate as drug resistant: (i) when a sensitive virus is used within each individual assay as a control, (ii) when ACV and PCV susceptibility is evaluated in human cells, and (iii) when the 10x above sensitive IC(50) criterion is used to classify a virus as drug-resistant. Testing of additional clinical samples is warranted to further confirm these findings. 相似文献
24.
Evans DL Kaur H Leary J Praveen K Jaso-Friedmann L 《Developmental and comparative immunology》2005,29(12):1049-1064
Nonspecific cytotoxic cells (NCC) are the first identified and most extensively studied killer cell population in teleosts. NCC kill a wide variety of target cells including tumor cells, virally transformed cells and protozoan parasites. The present study identified a novel evolutionarily conserved oligodeoxynucleotide (ODN) binding membrane protein expressed by channel catfish (Ictalurus punctatus) NCC. Peptide fingerprinting analysis of the ODN binding protein (referred to as NCC cationic anti-microbial protein-1/ncamp-1) identified a peptide that was used to design degenerate primers. A catfish NCC cDNA library was used as template with these primers and the PCR-amplified product was sequenced. The translated sequence contained 203 amino acids (molecular mass of 22,064.63 Da) with characteristic lysine rich regions and a pI=pH 10.75. Sequence comparisons of this protein indicated similarity to zebrafish (51.2%) histone family member 1-X and (to a lesser extent) to trout H1. A search of EST databases confirmed that ncamp-1 is also expressed in various tissues of channel catfish as well as zebrafish. Inspection for signature repeats in ncamp-1 and comparisons with histone-like peptides from different species indicated the presence of multiple lysine based motifs composed of AKKA or PKK repeats. The novel protein was cloned, expressed in E. coli and the recombinant was used to generate rabbit anti-serum. The recombinant ncamp-1 bound GpC and CpG ODNs and was detected with homologous anti-ncamp-1 polyclonal antibodies. Western blots of NCC membranes using anti-ncamp-1 serum detected a 29 kDa protein. Binding competition experiments demonstrated that anti-ncamp-1 antibodies and GpC bound to the same protein on NCC. Two different truncated forms of ncamp-1 as well as the full-length recombinant protein exhibited anti-microbial activity. The present study demonstrated the expression by NCC of a new membrane protein that may participate in the recognition of bacterial DNA and as such participate in innate anti-microbial immune responses in teleosts. 相似文献
25.
To find out the efficacy of sucralfate in preventing gastrointestinal side effects of non-steroidal anti-inflammatory drugs (NSAIDs) a prospective, randomised single blind study was conducted from 1989 to 1992. Patients with osteoarthritis, rheumatoid arthritis and other long standing painful conditions, who were expected to receive NSAIDs for over three months, were recruited into the study. All medicines were discontinued for a period of 10–15 days prior to initial endoscopic assessment. NSAID therapy was started and the patients were randomised to receive either placebo (group A) or sucralfate (group B) in addition. Patient were reassessed clinically every week and an endoscopic examination was repeated after 6–8 weeks of follow-up. A total of 176 patients were studied in group A (n=91) and group B (n=85). At the end of 8 weeks gastrointestinal symptoms were present in 30.6% and 26.4% patients of group A and B respectively. Endoscopic assessment showed superficial lesions in 36.5% and 18.7% while endoscopic ulcer in 2.4% and 1.1% patients of groups A and B respectively. Thus in patients receiving chronic NSAID therapy, simultaneous administration of sucralfate reduces the incidence of superficial gastric lesions but has no significant effect on symptoms or ulcer formation.KEY WORDS: Gastropathy, Sucralfate, Nonsteroidal anti-inflammatory drugs 相似文献
26.
27.
In third-world countries many children with epilepsy also suffer from malnutrition, anemia, liver disease, and immunosuppression. Doctors might have reservations about the use of anticonvulsants that could aggravate these disorders. The purpose of this study was to establish the prevalence of abnormal blood and serum values in children receiving carbamazepine or sodium valproate as monotherapy who attended a child neurology clinic serving a third-world community in Cape Town, South Africa Blood samples were taken at routine follow-up visits from 104 children who had been on carbamazepine or sodium valproate monotherapy for at least 6 months. Hematology, serum chemistry, immunoglobulins, and anticonvulsant levels were measured by standard laboratory procedures. Very few subjects had any values outside accepted normal ranges. When clinically indicated and available, carbamazepine and sodium valproate can be prescribed for children from a third-world environment. Frequent blood and serum testing is not necessary in asymptomatic individuals. 相似文献
28.
29.
MRI of the intraorbital optic nerve in patients with autosomal dominant optic atrophy 总被引:3,自引:0,他引:3
Votruba M Leary S Losseff N Bhattacharya SS Moore AT Miller DH Moseley IF 《Neuroradiology》2000,42(3):180-183
Measurements of the intraorbital optic nerve were made using high-resolution coronal MRI in 10 adults with autosomal dominant
optic atrophy. Comparisons were made with previous studies of 10 normal adult subjects. The cross-sectional diameters of the
optic nerve and the perineural subarachnoid space were measured and a ratio of there diameters at anterior, mid and posterior
positions along the optic nerve was determined. We found a statistically significant difference in the mean optic nerve: sheath
ratio between the control group and patients with autosomal dominant optic atrophy. At anterior, mid and posterior locations
along the optic nerve it is significantly smaller in patients with optic atrophy. We have demonstrated that the loss of ganglion
cells, previously documented in dominant optic atrophy, is associated with a significant loss of optic nerve tissue and thinning
of the nerve along its length.
Received: 6 July 1999/Accepted: 22 July 1999 相似文献
30.
Frequency of the ATM IVS10-6T→G variant in Australian multiple-case breast cancer families
下载免费PDF全文
![点击此处可从《Breast cancer research : BCR》网站下载免费的PDF全文](/ch/ext_images/free.gif)