全文获取类型
收费全文 | 13587篇 |
免费 | 945篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 129篇 |
儿科学 | 537篇 |
妇产科学 | 374篇 |
基础医学 | 2109篇 |
口腔科学 | 387篇 |
临床医学 | 1671篇 |
内科学 | 2722篇 |
皮肤病学 | 353篇 |
神经病学 | 1280篇 |
特种医学 | 330篇 |
外科学 | 1065篇 |
综合类 | 101篇 |
一般理论 | 4篇 |
预防医学 | 1202篇 |
眼科学 | 200篇 |
药学 | 845篇 |
中国医学 | 16篇 |
肿瘤学 | 1240篇 |
出版年
2023年 | 102篇 |
2022年 | 157篇 |
2021年 | 304篇 |
2020年 | 277篇 |
2019年 | 333篇 |
2018年 | 325篇 |
2017年 | 293篇 |
2016年 | 337篇 |
2015年 | 431篇 |
2014年 | 529篇 |
2013年 | 727篇 |
2012年 | 1082篇 |
2011年 | 1060篇 |
2010年 | 648篇 |
2009年 | 553篇 |
2008年 | 896篇 |
2007年 | 934篇 |
2006年 | 896篇 |
2005年 | 857篇 |
2004年 | 822篇 |
2003年 | 750篇 |
2002年 | 678篇 |
2001年 | 145篇 |
2000年 | 93篇 |
1999年 | 121篇 |
1998年 | 159篇 |
1997年 | 140篇 |
1996年 | 87篇 |
1995年 | 86篇 |
1994年 | 73篇 |
1993年 | 67篇 |
1992年 | 51篇 |
1991年 | 48篇 |
1990年 | 31篇 |
1989年 | 33篇 |
1988年 | 39篇 |
1987年 | 32篇 |
1986年 | 20篇 |
1985年 | 27篇 |
1984年 | 24篇 |
1983年 | 37篇 |
1982年 | 21篇 |
1981年 | 28篇 |
1980年 | 25篇 |
1979年 | 15篇 |
1978年 | 17篇 |
1977年 | 26篇 |
1976年 | 14篇 |
1974年 | 13篇 |
1972年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
N K Veien F Hardt G Bendixen J Genner J Ringsted J Wanstrup A Wiik E Christiansen 《Acta medica Scandinavica》1978,203(4):321-326
The Kveim reaction was studied in vivo in 50 patients with sarcoidosis. Commonwealth Serum Laboratories Kveim material and a new Danish Kveim material gave 14 and 8 positive reactions respectively, as well as 6 and 8 equivocal reactions. Forty-six of the patients were also tested in vitro for cell mediated immunity to the Danish Kveim material, using both the leucocyte migration agarose technique and the capillary technique. No significant migration inhibition or stimulation were found. A tuberculin skin test was performed in 49 of the patients, and in 45 a dinitrochlorobenzene sensitivity titer was determined. Both tests revealed a depression of the cell mediated immunity. The serum levels of immunoglobulins IgG, IgA, IgM, IgD, and IgE were determined. The serum of each patient was also examined to determine if organ-non-specific and granulocyte-specific antinuclear factors of IgG class, antibodies against native DNA, rheumatoid factor, mitochondrial antibodies, antibodies against thyroid cytoplasm, and parietal cell antibodies were present. IgG levels were above normal in 28 patients; IgE was above normal in 10 patients, 4 of whom were atopics or had an atopic disposition. Organ-non-specific antinuclear factors were present in 17 patients. 相似文献
72.
Recombinant Helicobacter bilis Protein P167 for Mouse Serodiagnosis in a Multiplex Microbead Assay 下载免费PDF全文
Sunlian Feng Lon V. Kendall Emir Hodzic Scott Wong Edward Lorenzana Kimberly Freet Karin S. Ku Paul A. Luciw Stephen W. Barthold Imran H. Khan 《Clinical and Vaccine Immunology : CVI》2004,11(6):1094-1099
Infection of mice with Helicobacter bilis is widespread in research and commercial mouse colonies. Therefore, sensitive, specific, and high-throughput assays are needed for rapid and accurate testing of mice in large numbers. This report describes a novel multiplex assay, based on fluorescent microbeads, for serodetection of H. bilis infection. The assay requires only a few microliters of serum to perform and is amenable to a high-throughput format. Individual microbead sets were conjugated to purified, H. bilis-specific, recombinant proteins P167C and P167D and bacterial membrane extracts from H. bilis and Helicobacter hepaticus. For detecting H. bilis infection in the microbead multiplex assay, P167C and P167D provided significantly higher sensitivities (94 and 100%, respectively) and specificities (100 and 95%, respectively) than membrane extract (78% sensitivity and 65% specificity). Microbead multiplex assay results were validated by enzyme-linked immunosorbent assay. Purified recombinant proteins showed low batch-to-batch variation; this feature allows for ease of quality control, assay robustness, and affordability. Thus, recombinant antigens are highly suitable in the multiplex microbead assay format for serodetection of H. bilis infection. 相似文献
73.
Nowak DA Rosenkranz K Hermsdörfer J Rothwell J 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2004,156(4):444-450
When subjects repetitively lift an object, the grip force they select is influenced by the mechanical object properties of the preceding lift. Similar effects on grip force scaling are observed whether the subsequent lift is performed with the same hand or the hand contralateral to the preceding lift. Here we demonstrate that passive vibration of the hand muscles involved in the generation of grip force in the interval between two blocks of lifting trials interferes with predictive grip force scaling. Following ten trials in which subjects lifted an object with constant mechanical properties with the dominant hand, muscle vibration was given to the first interosseus and adductor pollicis muscles of the dominant hand during a 10-min rest period. Compared with the last lift preceding vibration, peak rates of grip force increase and peak grip forces were scaled too high during the first lift following vibration whether the lift was made with the dominant or non-dominant hand. Subjects scaled grip force accurately to the object properties within three lifts following vibration. If subjects rested for 10 min after the first ten trials and received no vibration, then there was no significant difference in the peak grip force or its rate of increase between the last lift preceding rest and the first lift following it. We suggest that vibration impairs the memory processes responsible for predictive grip force scaling. Our data are consistent with the recent suggestion that these memory processes are neither specific for a certain motor action nor do they reflect internal representations of mechanical object properties. 相似文献
74.
Schwärzler P Zech H Auer M Pfau K Göbel G Vanderzwalmen P Zech N 《Human reproduction (Oxford, England)》2004,19(9):2097-2102
BACKGROUND: Retrospective cohort study to evaluate differences in outcome when embryo transfer was performed either on day 2-3 (cleavage stage, CS-group) or on day 4-5 (blastocyst stage, BS-group). METHODS: A total of 1259 consecutive cycles yielding 500 live born babies performed at a single centre in Bregenz, Austria, were included. Main outcome measures were implantation and (multiple) pregnancy rates and neonatal outcome including birth defects. RESULTS: Total Pregnancy rate was 44% vs 28% (P < 0.001) and the total 'take home baby rate' was 37% vs 22% in the BS-group and the CS-group, respectively. Rate of multiple gestations (34% vs 17%, P = 0.001) was significantly higher among the BS-group, resulting in a higher rate of preterm deliveries < 36 weeks (26% vs 17%, P = 0.045). Female factor causing infertility (40% vs 21%, P < 0.001) was significantly higher among the BS-group. For the CS-group, rate of singleton pregnancies (83% vs 66%, P = 0.001) and idiopathic cause of infertility (34% vs 22%, P = 0.012) were significantly higher. No statistically significant differences were found in sex, Caesarean section rate, Apgar score and umbilical artery pH-values, total mean birth weight, admission rate to intensive care unit, days of hospitalization and number of minor and major birth defects. CONCLUSIONS: Our data suggest that blastocyst transfer may lead to a higher pregnancy rate with an overall better take-home baby rate (THBR) at the cost of higher rates of multiples and preterm deliveries. 相似文献
75.
Bidwell J Keen L Gallagher G Kimberly R Huizinga T McDermott MF Oksenberg J McNicholl J Pociot F Hardt C D'Alfonso S 《Genes and immunity》1999,1(1):3-19
The pathologies of many infectious, autoimmune and malignant diseases are influenced by the profiles of cytokine production in pro-inflammatory (TH1) and anti-inflammatory (TH2) T cells. Interindividual differences in cytokine profiles appear to be due, at least in part, to allelic polymorphism within regulatory regions of cytokine gene. Many studies have examined the relationship between cytokine gene polymorphism, cytokine gene expression in vitro, and the susceptibility to and clinical severity of diseases. A review of the findings of these studies is presented. An on-line version featuring appropriate updates is accessible from the World Wide Web site, http://www.pam.bris.ac.uk/services/GAI/cytokine4.htm. 相似文献
76.
The frequency distribution of Anisakis simplex L3 larvae between host tissues was investigated in three host species: saithe, cod and redfish. Fish were sampled from Norwegian
coastal waters and examined for the presence of A. simplex in muscle and viscera. In all three of the host species, A. simplex larvae were most frequently detected in the viscera; the percentages of total infection for saithe, cod and redfish were
99.6%, 97.8% and 88.0%, respectively. In general, the distribution patterns of A. simplex L3 between muscle and viscera were not significantly affected by host size. The observations that distributions vary between
species and are not affected by host size do not support an earlier hypothesis which states that A. simplex L3 distributions are determined by an optimal pre-encapsulation migratory distance within host tissues. In contrast, it is
suggested that A. simplex L3 distributions are governed by the conditions encountered within host tissues, and are possibly related to the availability
of nutrients.
Received: 9 July 1997 / Accepted: 15 September 1997 相似文献
77.
Increased phagocytic capacity of the blood,but decreased phagocytic activity per individual circulating neutrophil after an ultradistance run 总被引:3,自引:0,他引:3
Holger Gabriel Hans-Josef Müller Karin Kettler Lars Brechtel Axel Urhausen Wilfried Kindermann 《European journal of applied physiology》1995,71(2-3):281-283
The effect of a long strenuous endurance exercise on the phagocytic function of neutrophils was examined. 9 athletes [7 males, 2 females, age: 36–68 years, body mass: 64 (SD 10) kg, height: 175 (SD 10) cm] completed a competetive 100 km run in 8:07 (median value; range: 7:29–9:50 hours). In a whole blood assay the phagocytosis of opsonized E. coli, the receptor density of the Fc receptor 3 (CD16) and the complement receptor 3 (CD11b, direct immunofluorescence) of neutrophils were measured on a per cell basis by flow cytometry before and up to 3 hours after the race. The phagocytic rate (percentage of neutrophils incorporating bacteria) was unchanged after exercise, whereas the phagocytic activity (number of incorporated bacteria per cell) was significantly reduced by –34 (SD 8) % (Wilcoxon test, P<0.001). The total phagocytic capacity of the blood increased 2-3fold post exercise. The surface antigen expressions of CD11b and CD16 were unaffected by the ultradistance run. The results indicate either a reduced phagocytic function of neutrophils on a single cell basis or the mobilization of neutrophils of the marginal pool with a lower phagocytic activity. However, after a long endurance exercise the phagocytotic capacity of the blood was enhanced due to increased cell concentrations. 相似文献
78.
Mg2+-extrusion from Mg2+-loaded neurons of the leech, Hirudo medicinalis, is mediated mainly by Na+/Mg2+ antiport. However, in a number of leech neurons, Mg2+ is extruded in the nominal absence of extracellular Na+, indicating the existence of an additional, Na+-independent Mg2+ transport mechanism. This mechanism was investigated using electrophysiological and microfluorimetrical techniques. The rate of Na+-independent Mg2+ extrusion from Mg2+-loaded leech neurons was found to be independent of extracellular Ca2+, K+, NO3-, HCO3-, SO4(2-), HPO4(2-), and of intra- and extracellular pH. Na+-independent Mg2+ extrusion was not inhibited by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), furosemide, ouabain, vanadate, iodoacetate, 4-amino-hippurate, or alpha-cyano-4-hydroxycinnamate and was not influenced by changes in the membrane potential in voltage-clamp experiments. Na+-independent Mg2+ extrusion was, however, inhibited by the application of 2 mM probenecid, a blocker of organic anion transporters, suggesting that Mg2+ might be co-transported with organic anions. Extracellularly, of all organic anions tested (malate, citrate, lactate, alpha-ketoglutarate, and 4-amino-hippurate) only high, but physiological, concentrations of malate (30 mM) had a significant inhibitory effect on Na+-independent Mg2+ extrusion. Intracellularly, iontophoretically injected malate, citrate, or fura-2, but not Cl-, alpha-ketoglutarate, glutamate, succinate, or urate, were stimulating Na+-independent Mg2+ extrusion from those neurons that initially did not extrude Mg2+ in Na+-free solutions. Our data indicate that Mg2+ is co-transported with organic anions, preferably with malate, the predominant extracellular anion in the leech. The proposed model implies that, under experimental conditions, malate drives Mg2+ extrusion, whereas under physiological conditions, malate is actively taken up, driven by Mg2+, so that malate can be metabolized. 相似文献
79.
Knapik J Yachnis AT Ripley D Biegel JA Rathor S Hardt NS Talerman A Wilkinson EJ 《Human pathology》2001,32(8):884-886
We report a primary uterine sarcoma with classic histologic, immunohistochemical, and ultrastructural features of a malignant extrarenal rhabdoid tumor (MERT). It arose in a 71-year-old woman who presented with postmenopausal bleeding, ascites, and a right pelvic mass. Malignant cells with rhabdoid morphology were identified by cytologic examination of the peritoneal fluid. Exploratory laparotomy revealed a 10-cm right adnexal mass and disseminated peritoneal tumor. Pathologic study showed diffuse expansion of the endometrial stroma by rhabdoid-like cells with transmural infiltration of the myometrium and extensive involvement of uterine serosa and right ovary by tumor. Neoplastic cells were immunoreactive for vimentin, cytokeratin, and epithelial membrane antigen, and cytoplasmic whorls of intermediate filaments were observed by electron microscopy. Fluorescence in situ hybridization (FISH) studies with chromosome 22-specific probes showed no loss of the INI1 gene, and no coding sequence mutation was identified. 相似文献
80.
Lung dendritic cells are primed by inhaled particulate antigens, and retain MHC class II/antigenic peptide complexes in hilar lymph nodes for a prolonged period of time 下载免费PDF全文
Intratracheal (IT) administration of heat-killed Listeria monocytogenes (HKL) results in an influx of macrophage and dendritic cell (DC) precursors into the lung interstitium. Low-density, FcR+, interstitial lung cells isolated from rats instilled 24 hr before with HKL or vehicle alone, were > 90% Mar1+. After culturing with granulocyte-macrophage colony-stimulating factor (GM-CSF) for 3 days, up to 24% of the loosely adherent cells were DC that stimulated allogeneic T-cell proliferation in an mixed lymphocyte reaction (MLR) assay. After only an overnight incubation with GM-CSF, however, the capacity of interstitial Mar1+ cells to stimulate HKL immune T-cell proliferation without exogenous antigen was low. By contrast, when DC were isolated as major histocompatibility complex (MHC) class II+ cells from rat lungs at 1, 3, 7 and 14 days after HKL instillation and cultured overnight with GM-CSF, their antigen presentation capacity without added exogenous antigen was robust, but declined over the 2-week period. Interestingly, hilar lymph node DC maintained their HKL antigen-presenting capacity for up to 2 weeks after instillation of HKL. Following IT administration of PKH-26 labelled HKL, fluorescent or immunolabelled organisms were detected in OX62+ DC in airway epithelium, lung interstitium and hilar lymph nodes in situ and in MHC class II+ DC isolated from these sites. We conclude that newly immigrated Mar1+ lung DC precursors, while efficient in endocytosing particulate antigens, are incapable of eliciting a significant proliferative response from HKL-sensitized T cells. By contrast, MHC class II+ DC isolated from lungs and incubated overnight with GM-CSF induce vigorous antigen-specific T-cell proliferation. Antigen-loaded lung DC in hilar lymph nodes maintain their antigen presentation capacity for up to 2 weeks. 相似文献