全文获取类型
收费全文 | 2139篇 |
免费 | 116篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 193篇 |
妇产科学 | 26篇 |
基础医学 | 264篇 |
口腔科学 | 58篇 |
临床医学 | 261篇 |
内科学 | 501篇 |
皮肤病学 | 73篇 |
神经病学 | 73篇 |
特种医学 | 400篇 |
外科学 | 101篇 |
综合类 | 48篇 |
预防医学 | 105篇 |
眼科学 | 19篇 |
药学 | 90篇 |
2篇 | |
肿瘤学 | 115篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 13篇 |
2020年 | 15篇 |
2019年 | 18篇 |
2018年 | 35篇 |
2017年 | 23篇 |
2016年 | 23篇 |
2015年 | 40篇 |
2014年 | 50篇 |
2013年 | 63篇 |
2012年 | 36篇 |
2011年 | 43篇 |
2010年 | 90篇 |
2009年 | 89篇 |
2008年 | 57篇 |
2007年 | 95篇 |
2006年 | 58篇 |
2005年 | 56篇 |
2004年 | 26篇 |
2003年 | 23篇 |
2002年 | 34篇 |
2001年 | 39篇 |
2000年 | 31篇 |
1999年 | 35篇 |
1998年 | 130篇 |
1997年 | 157篇 |
1996年 | 137篇 |
1995年 | 109篇 |
1994年 | 118篇 |
1993年 | 100篇 |
1992年 | 36篇 |
1991年 | 38篇 |
1990年 | 45篇 |
1989年 | 56篇 |
1988年 | 49篇 |
1987年 | 45篇 |
1986年 | 51篇 |
1985年 | 45篇 |
1984年 | 27篇 |
1983年 | 20篇 |
1982年 | 30篇 |
1981年 | 30篇 |
1980年 | 27篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1977年 | 19篇 |
1976年 | 25篇 |
1975年 | 15篇 |
1946年 | 1篇 |
排序方式: 共有2330条查询结果,搜索用时 649 毫秒
971.
972.
应用导数光谱法考察苯呋洛尔溶液体外经皮渗透性 总被引:1,自引:0,他引:1
本文应用二阶导数紫外分光光度法考察了苯呋洛尔溶液体外经皮渗透性。考察了促进剂月桂氮(?)酮-丙二醉及PEG-400溶剂对其渗透性的影响。应用二阶导数紫外分光光度法消除了兔皮溶出物对一般紫外测定方法的干扰。结果表明:苯呋洛尔溶液具有体外经皮渗透性;月桂氮(?)酮-丙二醇系统及PEG-400均能增强苯呋洛尔溶液的体外经皮渗透性。 相似文献
973.
Montour-Proulx I Kuehn SM Keene DL Barrowman NJ Hsu E Matzinger MA Dunlap H Halton JM 《Journal of child neurology》2005,20(2):129-133
The purpose of this study was to examine cognitive functioning and neuroimaging in children with leukemia treated with the Pediatric Oncology Group 9605 protocol at the Children's Hospital of Eastern Ontario. Mean age at diagnosis was 4.88 +/- 2.54 years. The mean (n = 24) Wechsler Verbal and Performance IQ fell in the low-average range (87.33 +/- 15.69 and 84.83 +/- 19.11, respectively). Mean (n = 20) Verbal and Visual Memory Indexes of 82.95 +/- 15.46 and 88.30+/- 10.80, respectively, were obtained. The proportion of scores on measures of intelligence and memory falling > 1 SD below the normative mean was substantially higher than expected. Paired t-test suggested that Wechsler Verbal IQ and memory remained stable, whereas Wechsler Performance IQ declined significantly. The results of growth curve analyses replicated these findings and suggested a significant adverse effect of cumulative dosage of intrathecal methotrexate on estimated Wechsler Performance IQ. Although only two children experienced seizures, 78% of the group showed leukoencephalopathy on at least one magnetic resonance image. Reliance on seizures as a predictor of leukoencephalopathy might underestimate the incidence of neurotoxicity. 相似文献
974.
975.
Magnetic resonance (MR) imaging was performed on 15 healthy subjects to define the appearance of the iliopsoas muscle and on 15 patients with iliopsoas disease. Seven patients had tumorous involvement of the muscles, five had inflammatory disease, one had retroperitoneal hemorrhage, one had iliopsoas bursitis, and one had bilateral hypertrophy. MR imaging permitted delineation of the muscles and depiction of the disease condition. Transverse MR images alone almost always provided the necessary data to determine the origin and extent of disease. Sagittal images were occasionally useful in defining the extension of disease into the spine. T1-weighted images provided optimal contrast between the muscles and adjacent tissues, while T2-weighted images were more useful for depicting disease within the muscles themselves. 相似文献
976.
To ascertain the optimal treatment for carcinoma of the piriform sinus, the authors determined survival rates and local and regional tumor growth for two groups of patients: those treated by radiation therapy alone (n = 209) and those treated by radiation therapy combined with surgery (n = 154). The two groups were similar with respect to the characteristics of primary tumor stage and degree of nodal involvement. The overall 3-year and 5-year actuarial survival rates were 19.2% and 15.5%, respectively. For 5-year actuarial survival, there was no significant difference between patients with T1 and T2 tumors, but there was a significant difference between patients with T1 + T2 tumors versus those with T3 tumor. There was no significant difference in 3- and 5-year survival between patients with N0 and N1 nodal involvement and those with N1 and N2 involvement, but there was a significant difference between patients with N0 versus those with N3 involvement. The 5-year actuarial survival rate is significantly better for patients who underwent surgery followed by radiation therapy than for those who received only radiation therapy. However, for patients with early-stage (T1 and T2) tumors, radiation therapy alone controls local tumor growth as well as the combination of surgery and radiation therapy does. For each treatment group, the causes of death and patterns of failure were studied and compared with investigations to date. 相似文献
977.
Stempak D Gammon J Halton J Champagne M Koren G Baruchel S 《Clinical pharmacology and therapeutics》2005,77(3):226-228
978.
Kjeld?P?van Houwelingen Boukje?AC?van DijkEmail author Christina?A?Hulsbergen-van de Kaa Leo?J?Schouten Hanneke?JM?Gorissen Jack?A?Schalken Piet?A?van den Brandt Egbert?Oosterwijk 《BMC cancer》2005,5(1):57
Background
Biallelic von Hippel-Lindau (VHL) gene defects, a rate-limiting event in the carcinogenesis, occur in approximately 75% of sporadic clear-cell Renal Cell Carcinoma (RCC). We studied the VHL mutation status in a large population-based case group. 相似文献979.
Bone Mineral Density Increases in Trans Persons After 1 Year of Hormonal Treatment: A Multicenter Prospective Observational Study 下载免费PDF全文
Chantal M Wiepjes Mariska C Vlot Maartje Klaver Nienke M Nota Christel JM de Blok Renate T de Jongh Paul Lips Annemieke C Heijboer Alessandra D Fisher Thomas Schreiner Guy T'Sjoen Martin den Heijer 《Journal of bone and mineral research》2017,32(6):1252-1260
Sex steroids are important determinants of bone acquisition and bone homeostasis. Cross‐sex hormonal treatment (CHT) in transgender persons can affect bone mineral density (BMD). The aim of this study was to investigate in a prospective observational multicenter study the first‐year effects of CHT on BMD in transgender persons. A total of 231 transwomen and 199 transmen were included who completed the first year of CHT. Transwomen were treated with cyproterone acetate and oral or transdermal estradiol; transmen received transdermal or intramuscular testosterone. A dual‐energy X‐ray absorptiometry (DXA) was performed to measure lumbar spine (LS), total hip (TH), and femoral neck (FN) BMD before and after 1 year of CHT. In transwomen, an increase in LS (+3.67%, 95% confidence interval [CI] 3.20 to 4.13%, p < 0.001), TH (+0.97%, 95% CI 0.62 to 1.31%, p < 0.001), and FN (+1.86%, 95% CI 1.41 to 2.31%, p < 0.001) BMD was found. In transmen, TH BMD increased after 1 year of CHT (+1.04%, 95% CI 0.64 to 1.44%, p < 0.001). No changes were observed in FN BMD (–0.46%, 95% CI –1.07 to 0.16%, p = 0.144). The increase in LS BMD was larger in transmen aged ≥50 years (+4.32%, 95% CI 2.28 to 6.36%, p = 0.001) compared with transmen aged <50 years (+0.68%, 95% CI 0.19 to 1.17%, p = 0.007). In conclusion, BMD increased in transgender persons after 1 year of CHT. In transmen of postmenopausal age, the LS BMD increased more than in younger transmen, which may lead to the hypothesis that the increase in BMD in transmen is the result of the aromatization of testosterone to estradiol. © 2017 American Society for Bone and Mineral Research. 相似文献
980.
Bourgeois P; Bolcato-Bellemin AL; Danse JM; Bloch-Zupan A; Yoshiba K; Stoetzel C; Perrin-Schmitt F 《Human molecular genetics》1998,7(6):945-957
Most targeted gene mutations are recessive and analyses of gene function
often focus on homozygous mutant phenotypes. Here we describe parts of the
expression pattern of M-twist in the head of developing wild-type mice and
present our analysis of the phenotype of heterozygous twist- null animals
at around birth and in adults. A number of twist -null heterozygous mice
present skull and limb defects and, in addition, we observed other
malformations, such as defects in middle ear formation and the xyphoid
process. Our study is of interest to understand bone formation and the role
of M-twist during this process, as within the same animal growth of some
bones can be accelerated while for others it can be delayed. Moreover, we
show here that expressivity of the mouse mutant heterozygous phenotype is
dependent on the genetic background. This information might also be helpful
for clinicians, since molecular defects affecting one allele of the human
H-twist ( TWIST ) gene were identified in patients affected with
Saethre-Chotzen syndrome (SCS). Expressivity of this syndrome is variable,
although most patients present craniofacial and limb malformations
resembling those seen in mutant mice. Thus the mutant mouse twist -null
strain might be a useful animal model for SCS. The twist -null mutant mouse
model, combined with other mutant mouse strains, might also help in an
understanding of the etiology of morphological abnormalities that appear in
human patients affected by other syndromes.
相似文献