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31.
Fertility clinics worldwide routinely produce a large volume of 'waste' follicular aspirate, which is potentially an abundant source of immature ovarian follicles. Current attempts to cultivate these further in vitro to yield viable mature oocytes for fertility treatment have not yet achieved much success. Instead, recent lines of evidence have emerged that are suggestive of a potential stem cell niche within such immature ovarian follicles. The recent discovery of follicular renewal and putative germ-line stem cells within the postnatal mammalian ovary shook the foundations of reproductive biology by challenging the established dogma that mammalian females lose the capacity for germ cell renewal during fetal life, such that a fixed reserve of germ cells (oocytes) enclosed within follicles is endowed at birth. More intriguingly, another recent study in the Drosophila model provided compelling evidence that somatic progenies (nurse cells) of germ-line stem cells had the ability to revert back to the stem-cell-like state. This introduces the exciting possibility that within the mammalian ovarian follicle, similar somatic progenies of germ-line stem cells may also possess a greater intrinsic ability to revert back into functional stem cells. If this is the case, then a favored candidate would be the cumulus/granulosa of immature ovarian follicles, since such cells are true homologues of nurse cells found within the Drosophila ovary. The successful elucidation of a human germ-line stem cell niche within immature ovarian follicles is likely to have huge ramifications in stem cell biology and regenerative medicine.  相似文献   
32.
Bioavailablility of elderberry anthocyanins   总被引:2,自引:0,他引:2  
Considerable epidemiological evidence suggests a link between the consumption of diets rich in fruits and vegetables and a decreased risk of cardiovascular disease and cancers. Anthocyanins have received attention as important dietary constituents that may provide health benefits and contribute antioxidant capacity beyond that provided by essential micronutrients such as ascorbate, tocopherols, and selenium. The emergence of renewed interest by industrial countries in traditional herbal medicines and the development of 'functional foods' are stimulating the need for more information regarding the bioavailability and efficacy of plant polyphenols. Flavonoids represent a numerous group of secondary plant metabolites based on the structure of a pyran ring flanked by two or more phenyl rings and varying subtly in the degree of unsaturation and the pattern of hydroxylation or methylation. Flavonoids also vary in the type of sugar attached or the degree of polymerization. Anthocyanins, potent flavonoid antioxidants widely distributed in fruits, vegetables and red wines, normally occur in nature as glycosides, a form not usually considered as bioavailable. We have examined the bioavailability and pharmacokinetics of anthocyanins in humans. Anthocyanins were detected as glycosides in both plasma and urine samples. The elimination of plasma anthocyanins appeared to follow first-order kinetics and most anthocyanin compounds were excreted in urine within 4 h after feeding. The current findings appear to refute assumptions that anthocyanins are not absorbed in their unchanged glycosylated forms in humans.  相似文献   
33.
CD4+ T cells lacking the costimulatory molecule CD28 have been described both in elderly individuals and in chronic inflammatory disorders, one being rheumatoid arthritis (RA). We, in this study, provide a comprehensive characterization of cell surface markers on and function of such CD28nullCD4+ T cells, as well as correlations with clinical parameters. We conclude that of all surface markers associated with these cells, only CD57 and CD11b are expressed on the majority of them. This CD28null population occurred in one-third of patients with RA and was independent of clinical characteristics. The population was persistent and expanded in peripheral blood, but was excluded from the joint in most patients. Functionally, CD28nullCD4+ T cells were potent effector memory cells with regard to their proliferation and cytokine-secretion profiles. This capacity correlated with a hitherto unpublished surface phenotype, the cells being uniformly CCR7- and CD43high. Moreover, a new terminally differentiated CD45RA+CCR7- population of CD4+ T cells was identified. We would like to suggest that in the unbalanced immune system of patients with autoimmune disease and chronic infection an expanded CD28nullCD4+ T-cell population able to secrete high levels of cytokines is likely to contribute to disease manifestations.  相似文献   
34.
Pan J  Zhang M  Wang J  Wang Q  Xia D  Sun W  Zhang L  Yu H  Liu Y  Cao X 《Immunology letters》2004,94(1-2):141-151
Maturation of dendritic cells (DC) is critical for efficient antigen presentation and initiation of an immune response. Interferon-gamma (IFN-gamma) is an important Th1 cytokine. In this study, we investigated the role of IFN-gamma in DC maturation using either IFN-gamma receptor deficient- or IFN-gamma overexpression-models. We showed that immature DC generated in vitro from bone marrow (BM) progenitor cells produced low level of IFN-gamma. After LPS stimulation, DC produced more IFN-gamma, and IFN-gamma productions were at comparable levels among C57BL/6 mice-derived DC (C57BL/6 DC), wild-type 129 mice-derived DC (129 DC) and IFN-gamma receptor deficient 129 mice-derived DC (IFN-gammaR-/-DC). We found that IFN-gammaR-/-DC exhibited decreased expression of CD54, CD86, reduced capacity to secrete IL-1beta and IL-12p70, and impaired capacity to stimulate alloreactive T cells and to drive Th1 differentiation. Transfection of IFN-gamma gene into DC promoted DC to express higher CD40, CD54, CD80, CD86, CCR7 and I-Ab, secrete more IL-1beta and IL-12p70, and more potently activate both CD4 and CD8 T cells. These data suggest that IFN-gamma signaling pathway is important for the maturation of DC in an autocrine fashion.  相似文献   
35.
BACKGROUND: In babies born after ICSI procedures, an increase of de-novo sex chromosome abnormalities has been observed. Several hypotheses have been proposed to explain these findings: an increased rate of sex chromosome aneuploidy in sperm of oligozoospermic men, or a preferential location of the sex chromosomes in the sub-acrosomal region of the sperm nucleus which leads to a reduced DNA decondensation of this region. In order to investigate which theory may be more reliable, we studied the localization of sex chromosomes and their aneuploidy rate in sperm in men undergoing ICSI. METHODS: Using fluorescent in-situ hybridization we studied sex chromosome localization and the aneuploidy rate for sex chromosomes and chromosome 18 in 20 oligospermic men undergoing ICSI and in 10 controls. RESULTS: In 40.94 and 52.92% of cases, the X and Y chromosomes respectively were localized in the sub-acrosomal region of the sperm nucleus compared with only 14.29% of cases of chromosome 18 (P < 0.001). An increase of sex chromosome aneuploidy in sperm of oligospermic men was observed; 2.91 versus 0.69% of controls (P < 0.001). CONCLUSIONS: Sex chromosomes are localized preferentially in the sub-acrosomal region of sperm and sex chromosome aneuploidy rate in the sperm of oligozoospermic men is higher than in controls.  相似文献   
36.
In this paper, we report a pregnancy at risk for beta thalassaemia in which the fetal red blood cell volume was reduced while that of the mother was relatively great, so that the presence of a fetal red blood cell population in a mixed maternal-fetal sample was difficult to recognise. The molecular basis for these haematological phenotypes was clarified by follow up examination and alpha globin gene mapping. These indicated that the fetus was heterozygous for beta thalassaemia and had deletion of three alpha globin structural genes, while the mother, heterozygous for beta thalassaemia, also had deletion of two alpha globin structural genes. When the coinheritance of alpha thalassaemia is suspected, it is necessary to examine carefully the red blood cell distribution of a placental sample, so that the presence of a population of fetal red blood cells is not missed.  相似文献   
37.
The chemokine receptor CCR5 is encoded by the CMKBR5 gene located on the p21.3 region of human chromosome 3, and constitutes the major co- receptor for the macrophage-tropic strains of HIV-1. A mutant allele of the CCR5 gene, Delta ccr5 , was shown to provide to homozygotes with a strong resistance against infection by HIV. The frequency of the Delta ccr5 allele was investigated in 18 European populations. A North to South gradient was found, with the highest allele frequencies in Finnish and Mordvinian populations (16%), and the lowest in Sardinia (4%). Highly polymorphic microsatellites (IRI3.1, D3S4579 and IRI3.2, D3S4580 ) located respectively 11 kb upstream and 68 kb downstream of the CCR5 gene deletion were used to determine the haplotype of the chromosomes carrying the Delta ccr5 variant. A strong linkage disequilibrium was found between Delta ccr5 and specific alleles of the IRI3.1 and IRI3.2 microsatellites: >95% of the Delta ccr5 chromosomes carried the IRI3.1-0 allele, while 88% carried the IRI3.2-0 allele. These alleles were found respectively in only 2 or 1.5% of the chromosomes carrying a wild-type CCR5 gene. From these data, it was inferred that most, if not all Delta ccr5 alleles originate from a single mutation event, and that this mutation event probably took place a few thousand years ago in Northeastern Europe. The high frequency of the Delta ccr5 allele in Caucasian populations cannot be explained easily by random genetic drift, suggesting that a selection advantage is or has been associated with homo- or heterozygous carriers of the Delta ccr5 allele.   相似文献   
38.
The formation of calcium oxalate nephrolithiasis can be estimated by measuring the concentration of calcium oxalate versus the inhibitory role of crystal formation in the urine. In recent studies, the calcium oxalate saturation index and the inhibitory activity (by modified Sarig's method) of the urine during fasting and after oral calcium loading in normal subjects and in patients with calcium nepliro- lithiasis were determined. It was shown that, in normal comrols after calcium loading the inhibitory activity of the urine increased in parallel with the increase in urinary excretion of calcium oxalate; in contrast, in patients with kidney stones, it remained unchanged or fell slightly. This abnormal response might result in a disturbance of the saturation-inhibi- tion balance and formation of kidney stone. In normal individuals, there may be a "protective re- sponse" to prevent the precipitation of calcium oxalate when the urrine is oversaturated with calcium oxalate while a defect of the "protective response" in patients may be an important factor in calcium oxalate stone formation.  相似文献   
39.
术前孤立性CRP升高与体外循环术后并发症的相关性   总被引:1,自引:0,他引:1  
目的探讨无感染的、术前孤立性C-反应蛋白(CRP)增加,对于体外循环心脏术后的结果,是否有预测性价值。方法分术前孤立性CRP升高(10.5~70.2mg/L)50例(A组)与CRP正常(<10mg/L)50例对照(B组),B组匹配A组在年龄、性别和疾病种类,两组均进行体外循环心脏手术。结果A组脓毒性并发症(20%)比对照组(2%)多(P<0.01)。这些病人微生物学阳性仅10%。A组中需要儿茶酚胺支持的占28%,而B组仅12%(P<0.05)。A组较B组术后需呼吸机支持的时间明显延长(25.2±6.2h比6.6±0.5h)(P<0.01)、ICU滞留时间也较B组长(4.6±0.8d比2.6±0.3d)(P<0.05)。结论术前孤立性CRP升高的病人,体外循环术后,发生脓毒性并发症的可能性明显增加。且大多数病例微生物学实验阴性,推测大多数脓毒性并发症是由于全身炎症反应综合征的原因。  相似文献   
40.
目的:总结颈部囊肿与瘘管的诊治经验。方法:93例行手术治疗,其中鳃裂囊肿15例,鳃裂瘘管10例,皮样囊肿1例,囊状淋巴管瘤4例,甲状舌骨囊肿37例,甲状舌管瘘管25例,癌性淋巴液囊肿1例,随访1-10年。结果:93例中,囊性淋巴管瘤1例复发后失访,另1例行2次手术,癌性淋巴液囊肿1例半年后死于肺转移,鳃裂瘘管2例3次手术,甲状舌管瘘管1例复发,鳃裂瘘管术后1例迟发性面瘫,一次手术治愈,无术后并发症。结论:颈部囊肿与瘘管的诊断除依据术前检查外,主要是依据术中的发现和术后病理检查。B超、CT等是有效的辅助检查.手段治疗上应彻底切除囊壁与瘘管,避免复发。术中应避免损伤颈部的大血管和神经。甲状舌管瘘管须切除舌骨中段2cm,这是防止术后复发的关键。  相似文献   
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