全文获取类型
收费全文 | 18477篇 |
免费 | 1346篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 112篇 |
儿科学 | 552篇 |
妇产科学 | 513篇 |
基础医学 | 2693篇 |
口腔科学 | 345篇 |
临床医学 | 2114篇 |
内科学 | 3647篇 |
皮肤病学 | 325篇 |
神经病学 | 1932篇 |
特种医学 | 594篇 |
外科学 | 1737篇 |
综合类 | 159篇 |
现状与发展 | 1篇 |
一般理论 | 20篇 |
预防医学 | 2018篇 |
眼科学 | 288篇 |
药学 | 1424篇 |
中国医学 | 56篇 |
肿瘤学 | 1338篇 |
出版年
2024年 | 26篇 |
2023年 | 243篇 |
2022年 | 386篇 |
2021年 | 675篇 |
2020年 | 463篇 |
2019年 | 734篇 |
2018年 | 717篇 |
2017年 | 570篇 |
2016年 | 563篇 |
2015年 | 612篇 |
2014年 | 798篇 |
2013年 | 1033篇 |
2012年 | 1648篇 |
2011年 | 1556篇 |
2010年 | 805篇 |
2009年 | 759篇 |
2008年 | 1215篇 |
2007年 | 1223篇 |
2006年 | 1028篇 |
2005年 | 1085篇 |
2004年 | 939篇 |
2003年 | 806篇 |
2002年 | 762篇 |
2001年 | 121篇 |
2000年 | 60篇 |
1999年 | 98篇 |
1998年 | 125篇 |
1997年 | 121篇 |
1996年 | 71篇 |
1995年 | 69篇 |
1994年 | 64篇 |
1993年 | 54篇 |
1992年 | 41篇 |
1991年 | 30篇 |
1990年 | 37篇 |
1989年 | 26篇 |
1988年 | 31篇 |
1987年 | 35篇 |
1986年 | 32篇 |
1985年 | 21篇 |
1984年 | 16篇 |
1983年 | 10篇 |
1982年 | 27篇 |
1981年 | 21篇 |
1980年 | 10篇 |
1979年 | 11篇 |
1978年 | 9篇 |
1977年 | 11篇 |
1975年 | 8篇 |
1972年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
Intermittent preventive sulfadoxine-pyrimethamine treatment of primigravidae reduces levels of plasma immunoglobulin G, which protects against pregnancy-associated Plasmodium falciparum malaria 下载免费PDF全文
Staalsoe T Shulman CE Dorman EK Kawuondo K Marsh K Hviid L 《Infection and immunity》2004,72(9):5027-5030
Pregnancy-associated malaria (PAM) is an important cause of maternal and neonatal suffering. It is caused by Plasmodium falciparum capable of inhabiting the placenta through expression of particular variant surface antigens (VSA) with affinity for proteoglycans such as chondroitin sulfate A. Protective immunity to PAM develops following exposure to parasites inhabiting the placenta, and primigravidae are therefore particularly susceptible to PAM. The adverse consequences of PAM in primigravidae are preventable by intermittent preventive treatment (IPTp), where women are given antimalarials at specified intervals during pregnancy, but this may interfere with acquisition of protective PAM immunity. We found that Kenyan primigravidae receiving sulfadoxine-pyrimethamine IPTp had significantly lower levels of immunoglobulin G (IgG) with specificity for the type of parasite-encoded VSA-called VSA(PAM)-that specifically mediate protection against PAM than did women receiving a placebo. VSA(PAM)-specific IgG levels depended on the number of IPTp doses received and were sufficiently low to be of clinical concern among multidose recipients. Our data suggest that IPTp should be extended to women of all parities, in line with current World Health Organization recommendations. 相似文献
44.
In stimulated neutrophils, the majority of tyrosine phosphorylated proteins are concentrated in Triton X-100 or NP-40 insoluble fractions. Most immunobiochemical studies, whose objective is to study the functional relevance of tyrosine phosphorylation are, however, performed using the supernatants of cells lysed in non-ionic detergent-containing buffers (RIPA lysis buffers). This observation prompted us to develop an alternative lysis protocol. We established a procedure involving the sequential lysis of neutrophils in buffers of increasing tonicities that not only preserved and solubilized tyrosine phosphorylated proteins but also retained their enzymatic activities. The sequential lysis of neutrophils in hypotonic, isotonic and hypertonic buffers containing non-ionic detergents resulted in the solubilisation of a significant fraction of tyrosine phosphorylated proteins. Furthermore, we observed that in monosodium urate crystals-stimulated neutrophils, Lyn activity was enhanced in the soluble fraction recovered from the hypertonic fraction, but not from that of the first hypotonic lysis. The distribution of tyrosine phosphorylated proteins between the NP-40 soluble and insoluble fractions was both substrate- and agonist-dependent. In neutrophils stimulated with fMet-Leu-Phe, MSU crystals or by CD32 ligation, the tyrosine phosphorylated proteins were mostly insoluble. On the other hand, in GM-CSF-treated cells, the phosphoproteins were more equally distributed between the two fractions. The results of this study provide a new experimental procedure for the investigation of tyrosine phosphorylation pathways in activated human neutrophils which may also be applicable to other cell types. 相似文献
45.
Hilary Pinnock Lorraine Adlem Suzanne Gaskin Jan Harris Caroline Snellgrove Aziz Sheikh 《The British journal of general practice》2007,57(542):714-722
BACKGROUND: Attendance for routine asthma reviews is poor. A recent randomised controlled trial found that telephone consultations can cost-effectively and safely enhance asthma review rates; however, concerns have been expressed about the generalisability and implementation of the trial's findings. AIM: To evaluate the effectiveness of a telephone option as part of a routine structured asthma review service. DESIGN OF STUDY: Phase IV controlled before-and-after implementation study. SETTING: A large UK general practice. METHOD: Using existing administrative groups, all patients with active asthma (n = 1809) received one of three asthma review services: structured recall with a telephone-option for reviews versus structured recall with face-to-face-only reviews, or usual-care (to assess secular trends). Main outcome measures were: proportion of patients with active asthma reviewed within the previous 15 months (Quality and Outcomes Framework target), mode of review, enablement, morbidity, and costs to the practice. RESULTS: A routine asthma review was provided for 397/598 (66.4%) patients in the telephone-option group compared with 352/654 (53.8%) in the face-to-face-only review group: risk difference 12.6% (95% confidence interval [CI] = 7.2 to 17.9, P<0.001). The usual-care group achieved a review rate of 282/557 (50.6%). Morbidity was equivalent in the three groups; however, enablement (P = 0.03) and confidence (P = 0.007) in asthma management were greater in the telephone-option versus face-to-face-only group. The cost per review achieved by providing the telephone-option service was lower than the face-to-face-only service (10.03 pounds versus 12.74 pounds, mean difference 2.71 pounds; 95% CI = 1.92 to 3.50, P<0.001); usual-care costs were 11.85 pounds per review achieved. CONCLUSION: Routinely offering telephone reviews cost-effectively increased asthma review rates, enhancing patient enablement and confidence with management, with no detriment to asthma morbidity. Practices should consider a telephone option for their asthma review service. 相似文献
46.
Damoiseaux JG Bouten B Linders AM Austen J Roozendaal C Russel MG Forget PP Tervaert JW 《Journal of clinical immunology》2002,22(5):281-288
Both celiac disease and inflammatory bowel disease (IBD) are characterized by chronic diarrhea and the presence of distinct (auto)antibodies. In the present study we wanted to determine the prevalence of serological markers for inflammatory bowel disease, i.e., perinuclear antineutrophil cytoplasmic antibodies (pANCA) and/or anti-Saccharomyces cerevisiae antibodies (ASCA), in 37 patients with biopsy-confirmed celiac disease (Marsh IIIb/c). The majority of the patients was positive for IgA (auto)antibodies typically associated with celiac disease, i.e., antiendomysium antibodies (EMA) (86.5%), antigliadin antibodies (AGA) (73%), and antirecombinant human tissue transglutaminase antibodies (rh-tTGA) (86.5%). Four patients with selective IgA deficiency could be identified by analyzing EMA, AGA, and rh-tTGA for the IgG isotype. The prevalence of pANCA and ASCA, markers that are used for IBD, was unexpectedly high in our cohort of patients with celiac disease: 8 patients were positive for pANCA (IgG) and 16 patients were positive for ASCA (IgG and/or IgA). These results indicate that the presence of pANCA or ASCA in the serum of patients with chronic diarrhea does not exclude celiac disease. A prospective study is required to determine whether pANCA and/or ASCA identify patients at risk for developing secondary autoimmune disease. 相似文献
47.
O'Dell SD Syddall HE Sayer AA Cooper C Fall CH Dennison EM Phillips DI Gaunt TR Briggs PJ Day IN 《European journal of human genetics : EJHG》2002,10(11):749-752
Ciliary neurotrophic factor (CNTF) administration reduces weight in leptin-resistant mice via the signalling pathway normally activated by leptin. A G>A null mutation in the CNTF gene results in complete absence of protein. We hypothesised that absence of CNTF could lead to diminished initiation of anorectic pathways, with consequent increase in body mass. In 575 Caucasian men aged 59-73 years, the A/A genotype (frequency 1.9%) was associated with a 10 kg increase in weight (P=0.03, 2 df) and 3 kg/m(2) greater BMI (P=0.02, 2 df). There was no effect in women. The CNTF G>A null mutation therefore confers a moderate effect on obesity in males of A/A genotype, who represent 1% of the general population. 相似文献
48.
Charvat S Le Griel C Chignol MC Schmitt D Serres M 《Clinical & experimental metastasis》1999,17(8):677-685
Cell migration is an essential process in physiological and pathological conditions such as wound healing and tumor invasion.
This phenomenon involves cell adhesion on the extracellular matrix mediated by integrins, and cell detachment promoted in
part by metalloproteinases (MMPs). In the present study, the migration of two HaCaT-ras clones (metastatic or not), was compared with HaCaT cells, and normal human primary cultured keratinocytes. Using colloidal
gold migration assay, the migration index on type I and type IV collagen was similar for primary cultured keratinocytes and
HaCaT, whereas it was markedly higher for the HaCaT-ras clones. High motility of ras-transfected cells was confirmed from an in vitro wound healing assay. It was not correlated with changes in integrin expression or related to a different adhesion on extracellular
matrix. The Marismastat (BB-2516), a MMP inhibitor, inhibited in a dose-dependent effect the migration in both assays, demonstrating
the important role of MMPs in the migration process. Under our experimental conditions, MMP-1 activity was not detected in
HaCaT and MMP-9 activity was secreted by these cells only after their stimulation by EGF. Here, MMP-2 was the major gelatinolytic
activity secreted by all the cells and its secretion was markedly higher for HaCaT-ras clones compared with HaCaT. In addition, Western blotting results confirmed a higher expression of MMP-2 associated with
a lower expression of TIMP-2 in HaCaT-ras compared with HaCaT. These results suggest that Ha-ras oncogene could be a stimulating factor of migration and might modified the balance between MMP-2 and TIMP-2 in keratinocyte
cell lines.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
49.
Male A Davies A Bergbaum A Keeling J FitzPatrick D Mackie Ogilvie C Berg J 《European journal of human genetics : EJHG》2002,10(12):807-812
Anophthalmia or microphthalmia occur in approximately one in 10 children who have severe visual impairment. These eye malformations are often of unknown aetiology, but can be inherited in autosomal dominant, recessive or X-linked forms, and can also occur in association with specific chromosome abnormalities. Four children are described in the medical literature with microphthalmia or anophthalmia in association with chromosome rearrangements involving distal 3q, suggesting the presence of a micro/anophthalmia gene in this region. We have identified two further patients with micro/anophthalmia and chromosome rearrangements involving 3q26-->3q27 and identified a 6.7 MB common deleted region. Patient 1 had multiple abnormalities including bilateral anophthalmia, abnormalities of the first and second cranial nerves and partial absence of the corpus callosum. His karyotype was 46,XY,del(3)(q26.33q28). Patient 2 had right anophthalmia and left extreme microphthalmia. Her karyotype was 46,XX,del(3)(q26.33q28)t(3;7)(q28;q21.1). Both patients had intrauterine growth retardation (IUGR) and strikingly similar dysmorphic facies consisting of bossed forehead, downward-slanting palpebral fissures, grooved bridge of the nose, prominent low-set ears, small down-turned mouth and small mandible. We identified BAC clones mapping to distal 3q from the ENSEMBL and NCBI Entrez databases. These BAC clones were used as fluorescence in situ hybridisation (FISH) probes to identify the minimum deleted region common to both patients. This interval, between clones RPC11-134F2 and RPC11-132N15, was estimated to be 6.7 MB. We conclude that there is an anophthalmia locus within this interval. Candidate genes mapping to this region include Chordin and DVL3, a homologue of the Drosophila Dishevelled gene. 相似文献
50.
Myoblasts fail to stimulate T cells but induce tolerance 总被引:1,自引:0,他引:1
Warrens Anthony N.; Zhang Jun Yan; Sidhu Sid; Watt Diana J; Lombardi Giovanna; Sewry Caroline A; Lechler Robert I. 《International immunology》1994,6(6):847-853
Recent interest in myoblast transfer and in the use of myoblastsas vehicles in gene therapy has made it important to understandthe potential immunogenicity of allogeneic or neoantlgen-expresslngmyoblasts. Given the problems of producing a pure populationof myoblasts, In this study we used a tumour-derived musclecell line (TE671), with phenotyplc features of myoblasts, whichwe transfected to express HLA-DR1. However, this cell line wasunable to stimulate either established HLA-DR1-specific alloreactlveT cell clones or a primary alloresponse. Nor could it presenthaemagglutlnln peptide HA 306–324 to DR1-restricted, HA306–324-speciflc T cell clones or lines. Indeed, prelncubatlonwith DR1-expressing TE671 and HA 306–324 rendered suchT cells tolerant as Judged by their subsequent inability toproliferate in response to a DR1+ B cell line plus peptide HA306–324. These results imply that myoblasts do not providecostlmulatory signals, and are therefore unlikely to stimulateallospeclfic T cells following myoblasts transplantation orto initiate neoantlgen-speclfic immune responses following Invivo transfection. 相似文献