全文获取类型
收费全文 | 14050篇 |
免费 | 1329篇 |
国内免费 | 632篇 |
专业分类
耳鼻咽喉 | 66篇 |
儿科学 | 124篇 |
妇产科学 | 496篇 |
基础医学 | 2215篇 |
口腔科学 | 252篇 |
临床医学 | 885篇 |
内科学 | 1659篇 |
皮肤病学 | 177篇 |
神经病学 | 820篇 |
特种医学 | 393篇 |
外国民族医学 | 12篇 |
外科学 | 698篇 |
综合类 | 2155篇 |
现状与发展 | 4篇 |
预防医学 | 1247篇 |
眼科学 | 157篇 |
药学 | 1870篇 |
14篇 | |
中国医学 | 730篇 |
肿瘤学 | 2037篇 |
出版年
2024年 | 43篇 |
2023年 | 160篇 |
2022年 | 369篇 |
2021年 | 533篇 |
2020年 | 450篇 |
2019年 | 303篇 |
2018年 | 342篇 |
2017年 | 417篇 |
2016年 | 440篇 |
2015年 | 580篇 |
2014年 | 879篇 |
2013年 | 939篇 |
2012年 | 893篇 |
2011年 | 994篇 |
2010年 | 847篇 |
2009年 | 788篇 |
2008年 | 819篇 |
2007年 | 844篇 |
2006年 | 685篇 |
2005年 | 610篇 |
2004年 | 567篇 |
2003年 | 507篇 |
2002年 | 405篇 |
2001年 | 350篇 |
2000年 | 290篇 |
1999年 | 248篇 |
1998年 | 194篇 |
1997年 | 167篇 |
1996年 | 159篇 |
1995年 | 139篇 |
1994年 | 119篇 |
1993年 | 70篇 |
1992年 | 62篇 |
1991年 | 76篇 |
1990年 | 84篇 |
1989年 | 62篇 |
1988年 | 47篇 |
1987年 | 40篇 |
1986年 | 43篇 |
1985年 | 53篇 |
1984年 | 71篇 |
1983年 | 35篇 |
1982年 | 56篇 |
1981年 | 41篇 |
1980年 | 50篇 |
1979年 | 26篇 |
1978年 | 29篇 |
1977年 | 21篇 |
1976年 | 23篇 |
1975年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Shields CM Taylor R Nazarenus T Cheatle J Hou A Tapprich A Haifley A Atkin AL 《Current genetics》2003,44(4):184-194
Saccharomyces cerevisiae ATS1 (-tubulin suppressor 1) was originally identified as a high-copy suppressor of class two -tubulin mutations and was proposed to have a regulatory role in coordinating the microtubule state with the cell cycle. Here, we show that Ats1p interacts with Nap1p, a cytoplasmic protein that regulates the activity of the Cdc28p/Clb2p complex. Loss of Nap1p results in a delayed switch from polar to isotropic bud growth. The delayed switch results in elongated buds. Nap1p and Ats1p interact in two-hybrid and co-immunoprecipitation assays. Both nap1 and ats1 cells have a Clb2p-dependent elongated bud morphology. Deletion of ATS1 partially suppresses the elongated bud morphology and benomyl resistance of nap1 mutants. Our results suggest Ats1p might regulate coordination of the microtubule state with the cell cycle through an interaction with Nap1p.Communicated by S. Hohmann 相似文献
62.
Acute liver failure was induced in rats by CCl4 administration and its effects on the hepatic Krebs cycle and gluconeogenic fluxes were evaluated in situ by 13C NMR isotopomer analysis of hepatic glucose following infusion of [U-13C]propionate. In fed animals, CCl4 injury caused a significant increase in relative gluconeogenic flux from 0.80+/-0.10 to 1.34 +/-0.24 times the flux through citrate synthase (p<0.01). In 24-h fasted animals, CCl4-injury also significantly increased relative gluconeogenic flux from 1.36+/-0.16 to 1.80+/-0.22 times the flux through citrate synthase (p<0.01). Recycling of PEP via pyruvate and oxaloacetate was extensive under all conditions and was not significantly altered by CCl4 injury. CCl4 injury significantly reduced hepatic glucose output by 26% (42.8+/-7.3 vs 58.1+/-2.4 micromol/kg/min, p=0.005), which was attributed to a 26% decrease in absolute gluconeogenic flux from PEP (85.6+/-14.6 vs 116+/-4.8 micromol/kg/min, p<0.01). These changes were accompanied by a 47% reduction in absolute citrate synthase flux (90.6+/-8.0 to 47.6+/-8.0 micromol/kg/min, p<0.005), indicating that oxidative Krebs cycle flux was more susceptible to CCl4 injury. The reduction in absolute fluxes indicate a significant loss of hepatic metabolic capacity, while the significant increases in relative gluconeogenic fluxes suggest a reorganization of metabolic activity towards preserving hepatic glucose output. 相似文献
63.
64.
A Heryudono R J Braun T A Driscoll K L Maki L P Cook P E King-Smith 《Mathematical medicine and biology》2007,24(4):347-377
We consider model problems for the tear film over multiple blink cycles that utilize a single equation for the tear film; the single non-linear partial differential equation that governs the film thickness arises from lubrication theory. The two models that we consider arise from considering the absence of naturally occurring surfactant and the case when the surfactant is strongly affecting the surface tension. The film is considered on a time-varying domain length with specified film thickness and volume flux at each end; only one end of the domain is moving, which is analogous to the upper eyelid moving with each blink. Realistic lid motion from observed blinks is included in the model with end fluxes specified to more closely match the blink cycle than those previously reported. Numerical computations show quantitative agreement with in vivo tear film thickness measurements under partial blink conditions. A transition between periodic and non-periodic solutions has been estimated as a function of closure fraction and this may be a criterion for what is effectively a full blink according to fluid dynamics. 相似文献
65.
Suzumori N Sugiura-Ogasawara M Katano K Suzumori K 《Human reproduction (Oxford, England)》2003,18(12):2595-2598
BACKGROUND: To assess the release of placental growth factor (PlGF) into peritoneal fluid in women with and without endometriosis, we measured its concentration with reference to disease stage, the presence of red endometriotic lesions and the phase of menstrual cycle. METHODS: Surgery was scheduled in the proliferative or secretory phase of the menstrual cycle for 59 women with (n = 35) or without (n = 24) endometriosis. The latter group comprised women undergoing surgery for ovarian cystadenomas. PlGF concentrations in the peritoneal fluid were measured using an enzyme-linked immunosorbent assay. RESULTS: PlGF concentration in the peritoneal fluid was markedly elevated in the endometriosis patients (median 189 pg/ml, interquartile range 84-475 pg/ml) as compared with the controls (88 pg/ml, 41-213 pg/ml; P < 0.001), especially in women with red lesions. Significantly greater values during the secretory phase of the menstrual cycle as compared with the proliferative phase were observed in both the control (cystadenoma) group (P < 0.05) and the endometriosis group (P < 0.001). CONCLUSIONS: Our findings suggest that production of PlGF is sensitive to the cyclic changes in ovarian steroids and may contribute to the pathogenesis of endometriosis, especially that of red lesions, by promoting neovascularization. 相似文献
66.
Fourteen women with primary dysmenorrhea were administered four sessions of systematic desensitization (SD) by either a male or a female therapist. The following measures were taken during the flow periods before and after treatment and at a 6-month follow-up: menstrual symptom checklist, medication usage, invalid hours, and menstrual attitudes. At pretreatment, menstrually distressed women had significantly higher scores on all measures compared to a normative group and an explicitly nondistressed group. At posttreatment, treated women's scores on the dependent variables were significantly reduced. All indices were reduced to a nondistressed level at posttreatment and at 6-month follow-up. Type of dysmenorrhea (congestive vs. spasmodic), trait anxiety level, and therapist sex did not predict differential responsiveness to SD. SD did not affect frontalis EMG, peripheral blood flow, or pain threshold. A Retrospective Symptom Scale of menstrual distress was found to be highly reliable, valid, and sensitive. 相似文献
67.
Calcium is an essential nutrient, particularly during growth and during reproduction, and the latter is probably why the avidity for calcium may be greater in females of some species. However, in humans, despite widespread belief in calcium appetite, it has not been studied experimentally. Here we compared the hedonic responses of 17 men and 24 women to test whether women show a greater avidity for calcium in line with its greater biological significance for them. We find no gender difference in the hedonic response to calcium, and no change with the menstrual cycle. 相似文献
68.
Reuvit Halperin Arie Herman Abraham Golan Eran Hadas David Schneider Ian Bukovsky Raphael Ron-El 《American journal of reproductive immunology (New York, N.Y. : 1989)》1996,35(2):102-105
PROBLEM: To examine the relationship between the concentration of uterine fluid human decidua-associated protein (hDP) 200, identified as a monoclonal rheumatoid factor, and different phases of the menstrual cycle. METHODS: Sequential measurements of hDP 200 concentration in uterine fluid were performed in 11 normal ovulatory women, aged 22–36 years. The samples were collected in early proliferative phase, late proliferative phase, periovulatory period, early secretory phase, and late secretory phase. RESULTS: Consistent fluctuations of hDP 200 levels in uterine fluid were found throughout the menstrual cycle. High levels were found during early proliferative phase and periovulatory period related to significantly lower levels during late proliferative and early luteal phases. CONCLUSION: There is menstrual phase dependent variation in the uterine fluid levels of hDP 200. 相似文献
69.
New HLA-A*11 allele,A*1112, identified by sequence-based typing 总被引:1,自引:0,他引:1
Garino E Belvedere M Berrino M Bertola L Dall'Omo AM Mazzola G Rossetto C Carcassi C Lai S Gay E Ricotti M Curtoni ES 《Tissue antigens》2002,60(1):84-87
In this report, we describe the identification of HLA-A*1112, a novel HLA-A*11 allele found in two Italian families. The new allele was detected during routine HLA typing by a polymerase chain reaction sequence-specific primer and was confirmed by high-resolution sequencing-based typing. The nucleotide sequences of HLA-A*1112 exons 2 and 3 are identical to HLA-A*11011 except for a single nucleotide substitution in codon 90 (GAC-->GCC). 相似文献
70.
Mendel Tuchman 《Human mutation》1993,2(3):174-178
Deletions of variable size involving one or more exons, 29 different missense, nonsense, or frameshift mutations, and three polymorphisms have been found in patients with ornithine transcarbamylase (OTC) deficiency. Most of the deletions and mutations were found in patients with severe disease manifested clinically as acute neonatal hyperammonemia. A small number of mutations or somatic mosaicism for deletions were found in males with “late onset” disease and in heterozygous females who were symptomatic. Approximately 10–15% of all molecular alterations associated with OTC defi ciency are large deletions involving all or part of the OTC gene with or without contiguous genes on the short arm of the X chromosome. Approximately 10% of all point mutations involve the CpG dinucleotide of codon 141 with a CGA→CAA transition producing a deleterious Arg→Gln substitu tion in position 109 of the mature enzyme and causing the elimination of a TaqI recognition site. The majority of the remaining mutations in the OTC gene are unique to the affected family and are usually not found in unrelated patients. To date, two mutations have been described in the sequence of the “leader” peptide, 23 mutations have been found in the coding sequence of the “mature” enzyme, and four mutations have been discovered in splicing recognition sites. Approximately 20 single base polymorphisms have been postulated to exist by comparing two reported OTC gene sequences; six of these substitutions cause amino acid changes of which three have been confirmed in patients. Of the known point mutations, 27 are single base substitutions: 17 missense, 6 nonsense, 4 splice site, and the remaining 2 are single base deletions. © 1993 Wiley-Liss, Inc. 相似文献