全文获取类型
收费全文 | 4336篇 |
免费 | 170篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 41篇 |
妇产科学 | 67篇 |
基础医学 | 578篇 |
口腔科学 | 105篇 |
临床医学 | 262篇 |
内科学 | 967篇 |
皮肤病学 | 274篇 |
神经病学 | 412篇 |
特种医学 | 181篇 |
外科学 | 783篇 |
综合类 | 21篇 |
预防医学 | 133篇 |
眼科学 | 35篇 |
药学 | 255篇 |
中国医学 | 5篇 |
肿瘤学 | 371篇 |
出版年
2022年 | 36篇 |
2021年 | 58篇 |
2019年 | 34篇 |
2018年 | 65篇 |
2017年 | 38篇 |
2016年 | 54篇 |
2015年 | 59篇 |
2014年 | 91篇 |
2013年 | 99篇 |
2012年 | 185篇 |
2011年 | 159篇 |
2010年 | 104篇 |
2009年 | 85篇 |
2008年 | 149篇 |
2007年 | 179篇 |
2006年 | 162篇 |
2005年 | 201篇 |
2004年 | 183篇 |
2003年 | 174篇 |
2002年 | 160篇 |
2001年 | 163篇 |
2000年 | 177篇 |
1999年 | 177篇 |
1998年 | 55篇 |
1997年 | 35篇 |
1996年 | 49篇 |
1995年 | 50篇 |
1994年 | 25篇 |
1993年 | 38篇 |
1992年 | 129篇 |
1991年 | 151篇 |
1990年 | 150篇 |
1989年 | 112篇 |
1988年 | 123篇 |
1987年 | 93篇 |
1986年 | 78篇 |
1985年 | 106篇 |
1984年 | 79篇 |
1983年 | 41篇 |
1982年 | 24篇 |
1981年 | 33篇 |
1979年 | 42篇 |
1978年 | 29篇 |
1977年 | 29篇 |
1975年 | 20篇 |
1974年 | 18篇 |
1973年 | 28篇 |
1972年 | 20篇 |
1971年 | 19篇 |
1967年 | 17篇 |
排序方式: 共有4513条查询结果,搜索用时 265 毫秒
41.
A 34-year-old male presented with central diabetes insipidus accompanied by upbeat nystagmus and cerebellar ataxia. The patient without family history of above began to walk at the age of 2 years. Polyposia and polyuria were noted at the age of about 4 years. Dysbasia developed at the age of about 7 years. From the age of 30, lalopathy appeared together with various clinical symptoms including cataracts, disturbed intelligence, upbeat nystagmus, abnormal ocular movements, ataxic speech, cerebellar ataxia and reduction of the muscle tone of the limbs, and hypotonic polyuria. Abnormal laboratory findings included square wave jerks, upbeat nystagmus, and "bow tie" nystagmus by EOG, atrophy of the cerebellum and the brainstem by CT, a slight prolongation of the P300 latency, and a central diabetes insipidus pattern by water deprivation test and Carter-Robbins tests. There have been occasional reports of diabetes insipidus complicated by cerebellar ataxia, but in no earlier reports has diabetes insipidus been concurrent with abnormal ocular movements such as upbeat nystagmus. A degenerative disease primarily of the posterior lobe of the hypophysis, hypothalamus, cerebellum, and brainstem was suspected. 相似文献
42.
N Iwai M Shibata F Mizoguchi H Nakamura M Katayama Y Taneda K Inokuma T Ozaki T Ichikawa S Matsui 《The Japanese journal of antibiotics》1989,42(12):2641-2660
Pharmacokinetic and clinical studies on cefmenoxime (CMX) in neonates and infants were conducted. 1. CMX 20 mg/kg was administered by intravenous bolus injection to 6 neonates (with ages 2 to 20 days) and 5 infants (with ages 36 to 107 days) and its serum concentration and urinary excretion rates were determined. In the neonates, serum concentrations of CMX after intravenous administration reached peak levels of 48.2 to 90.7 micrograms/ml (mean 70.4 +/- 14.3 micrograms/ml) in 1/4 hour, then declined with half-lives of 1.27 to 5.19 hours (mean 2.28 +/- 1.56 hours), and were 3.6 to 16.9 micrograms/ml (mean 8.3 +/- 6.0 micrograms/ml) at 6 hours. In the infants, serum concentrations at 1/4 hour were 67.5 to 111.0 micrograms/ml (mean 95.5 +/- 18.0 micrograms/ml); half-lives were 0.64 to 0.94 hour (mean 0.81 +/- 0.13 hour); and the serum concentrations at 6 hours were 0.2 to 1.1 micrograms/ml (mean 0.7 +/- 0.4 micrograms/ml). Mean peak serum concentrations in the neonates tended to be lower than those in the infants, but higher than those in children. Regarding the age differences of serum concentrations due to age in the neonates, their peak levels tended to be lower in younger ones. Half-lives were shorter in older subjects and, in early infancy, approached values observed in children. Urinary recovery rates in the first 6 hours after intravenous administration ranged from 43.6 to 87.5% (mean 61.6 +/- 14.6%) in the neonates and from 52.1 to 90.8% (mean 78.0 +/- 15.1%) in the infants. Thus, recovery rates were high even in younger subjects and tended to be higher in older subjects. 2. CMX was administered to 27 neonates and 4 infants to investigate its clinical effect, bacteriological effect and side effects. Clinical efficacy ratings of the drug in 19 neonate cases that could be evaluated (1 with purulent meningitis, 2 with suspected septicemia, 1 with acute bronchitis, 12 with acute pneumonia, 1 with impetigo, 1 with periumbilical abscess and 1 with acute pyelonephritis) were "excellent" in 14 cases, "good" in 4, and "poor" in 1. The efficacy rate covering "excellent" and "good" was 94.7%. In 4 infants (2 with acute pneumonia, 1 with periumbilical abscess and 1 with acute pyelonephritis), "excellent" was obtained in 2 cases and "good" in 2 cases. Thus, all the cases showed "good" or higher ratings. Bacteriologically, 1 strain of Staphylococcus aureus and 3 strains of Escherichia coli in neonates were eradicated while, in infants, 1 strain of S. aureus persisted but 1 of E. coli was eradicated.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
43.
We previously reported the expression profiles of 9 cytochrome P450 isozymes (CYPs) proteins and those of 40 CYPs genes in pregnant rat's liver, placenta and fetal liver after treatment with pregnenolone-16alpha-carbonitrile (PCN) or phenobarbital (PB). This study was carried out focusing on the gene expression profiles of Phase II drug metabolizing enzymes, Glutathione S-transferase isozymes (GSTs) and UDP-glycosyltransferase isozymes (UDPGTs). Fischer 344 (F344) pregnant rats were daily treated intraperitoneally with 50 mg/kg of PCN or 80 mg/kg of PB from 13 to 16 days of gestation (DG). They were sacrificed on 17 DG, and microarray analysis using Affymetrix Rat Expression Array 230 A was performed. Among 16 GSTs genes examined in this study, 7 genes were significantly induced in dam's liver and 3 genes in fetal liver, respectively, in the PCN-group, while 8 genes were significantly induced in dam's liver and 1 gene in fetal liver, respectively, in the PB-group. On the other hand, among 11 UDPGTs genes examined, 5 genes were significantly induced in dam's liver and 3 genes in fetal liver, respectively, in the PCN-group, while 5 genes were significantly induced in dam's liver and 1 gene in fetal liver, respectively, in the PB-group. There were no significant changes in the placenta of all groups. This is the first report of the gene expression profiles of Phase II drug metabolizing enzymes in pregnant rat and fetal livers and placenta after treatment with typical inducers of drug metabolizing enzymes. 相似文献
44.
Potentiation of allergic bronchoconstriction by repeated exposure to formaldehyde in guinea-pigs in vivo 总被引:2,自引:0,他引:2
T. Kita M. Fujimura S. Myou Y. Ishiura M. Abo N. Katayama M. Nishitsuji Y. Yoshimi S. Nomura Y. Oribe S. Nakao 《Clinical and experimental allergy》2003,33(12):1747-1753
BACKGROUND: Indoor formaldehyde (FA) might worsen allergies and be an underlying factor for the increasing incidence and severity of asthma; the exact mechanism, however, remains unclear. OBJECTIVE: The present study examined the effects of repeated exposure to FA on methacholine- and antigen-induced bronchoconstriction in guinea-pigs in vivo. METHODS: First, non-sensitized guinea-pigs were transnasally treated with 0.1 or 1.0% FA or saline three times a week for 6 weeks, and increasing concentrations of methacholine (50, 100, and 200 microg/mL) were inhaled at 5-min intervals. Second, guinea-pigs pre-treated with transnasal administration of FA or saline using the same protocol were passively sensitized with anti-ovalbumin (OA) serum 7 days before antigen challenge. Third, guinea-pigs were actively sensitized with OA and pre-treated with transnasal administration of FA or saline using the same protocol. The lateral pressure of the tracheal tube (Pao) was measured under anesthesia and artificial ventilation. RESULTS: The antigen-induced increase in Pao in actively sensitized guinea-pigs was significantly potentiated by FA exposure in a dose-dependent manner. The dose-response curve of the methacholine-induced increase in Pao in non-sensitized guinea-pigs or of the antigen-induced increase in Pao in passively sensitized guinea-pigs was not altered by FA exposure. Transnasal administration of FA significantly increased the serum anti-OA homocytotropic antibody titre (IgG) as measured by the passive cutaneous anaphylaxis reaction in actively sensitized guinea-pigs. CONCLUSION: The results suggest that repeated exposure to FA worsens allergic bronchoconstriction through enhancing antigen sensitization. 相似文献
45.
46.
Tetsushi Furukawa Tei-ichi Yamane Tomoko Terai Yoshifumi Katayama Masayasu Hiraoka 《Pflügers Archiv : European journal of physiology》1996,431(4):504-512
The role of the cytoskeleton in the rundown and reactivation of adenosine triphosphate (ATP) sensitive K+ channels (KATP channels) was examined by perturbing selectively the intracellular surface of inside-out membrane patches excised from guinea-pig ventricular myocytes. Actin filament-depolymerizing agents (cytochalasins and desoxyribonuclease I) accelerated channel rundown, while actin filament stabilizer (phalloidin) or phosphatidylinositol biphosphate (PIP2; inhibitor of F-actin-severing proteins) inhibited spontaneous and/or Ca2+-induced rundown. When rundown was induced by cytochalasin D or by long exposure to high Ca2+, channel activity could not be restored by exposure to MgATP, but application of F-actin with MgATP could reinstitute channel activity. The processes of rundown and reactivation of cardiac KATP channels may thus be influenced by the assembly and disassembly of the actin cytoskeletal network, which provides a novel regulatory mechanism of this channel. 相似文献
47.
Specific amplification of Rickettsia tsutsugamushi DNA from clinical specimens by polymerase chain reaction. 总被引:1,自引:4,他引:1
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Y Furuya Y Yoshida T Katayama F Kawamori S Yamamoto N Ohashi A Tamura A Kawamura Jr 《Journal of clinical microbiology》1991,29(11):2628-2630
Polymerase chain reaction (PCR) was used to detect Rickettsia tsutsugamushi-specific DNA in clinical specimens. The primer pair used for PCR was designed from the nucleotide sequence of the gene encoding the 56-kDa antigen of the Gilliam strain. Theses primers led to a 78-bp fragment by amplifying the genomic DNAs from five serovariants, i.e., the Gilliam, Karp, Kato, Kawasaki, and Kuroki strains of R. tsutsugamushi, and also the DNA from blood clots of patients with scrub typhus, even at the early stage of onset of the disease. This indicates that this method is suitable for the diagnosis of scrub typhus. 相似文献
48.
Are cerebrovascular factors involved in Alzheimer's disease? 总被引:13,自引:0,他引:13
Kudo T Imaizumi K Tanimukai H Katayama T Sato N Nakamura Y Tanaka T Kashiwagi Y Jinno Y Tohyama M Takeda M 《Neurobiology of aging》2000,21(2):215-224
Recent epidemiological studies have shown that vascular risk factors may be involved in Alzheimer's disease (AD) as well as dementia in general. To investigate the relation between a vascular disorder and AD pathology, current criteria are defective because most depend on exclusion of a cerebrovascular disorder. Epidemiological studies have indicated the possibilities that arteriosclerosis, abnormal blood pressure, diabetes mellitus and smoking may be related to the pathogenesis of AD. As for the mechanism that vascular disorders influence AD, it is presumed that amyloid deposition may be caused by a vascular disorder. Alternatively, a vascular event may cause progression of subclinical AD to a clinical stage. Insulin resistance and apolipoprotein E may also be involved in these mechanisms. Our studies show that ischemia-induced the Alzheimer-associated gene presenilin 1 (PS1) and endoplasmic reticulum-stress, generated from a vascular disorder, may unmask clinical AD symptoms caused by presenilin mutation, suggesting that a vascular factor might be involved in the onset of familial AD. 相似文献
49.
Yukio Nishimoto Tsukasa Iwahashi Toru Nishihara Hiroyuki Katayama Koichi Kueibayashi Toshihiko Takao Koji Saito 《Pathology international》1987,37(1):155-166
An autopsy case of hepatitis associated aplastic anemia was presented. A 58-year-old Japanese female with non-A, non-B hepatitis was admitted on August 2, 1983. Moderate grade of fever and hemorrhagic diathesis appeared on September 16, when hepatitis was evaluated as being under resolving. The peripheral blood and bone marrow findings were consistent with aplastic anemia. Since infection was suggested by increased levels of serum gamma-globulin and CRP, treatment with antibiotics as well as prednisolone and blood transfusion was initiated. Since September 21, gradual tenderness and edema on the right lower abdominal wall appeared. She died on October 3.
On postmortem examination, systemic plasmacytosis with lymphadenopathy and septic monilial infection was revealed. Numerous plasma cells were atypical, but were immunohistochemically proved to be polyclonal. The bone marrow showed a massive and diffuse plasma cell proliferation with extremely scarce myeloid cells and megakaryocytes. There was a large granulomatous lesion with monilial infection in the wall of the ileocecum. By these findings, systemic plasmacytosis was suspected to be due to chronic monilial infection.
The pathogenesis of systemic plasmacytosis in aplastic anemias and in other diseases were discussed with relation to the present case. 相似文献
On postmortem examination, systemic plasmacytosis with lymphadenopathy and septic monilial infection was revealed. Numerous plasma cells were atypical, but were immunohistochemically proved to be polyclonal. The bone marrow showed a massive and diffuse plasma cell proliferation with extremely scarce myeloid cells and megakaryocytes. There was a large granulomatous lesion with monilial infection in the wall of the ileocecum. By these findings, systemic plasmacytosis was suspected to be due to chronic monilial infection.
The pathogenesis of systemic plasmacytosis in aplastic anemias and in other diseases were discussed with relation to the present case. 相似文献
50.
N Koyama K Ohara H Yokota T Kurome M Katayama F Hino I Kato T Akai 《Journal of immunological methods》1991,139(1):17-23
A highly sensitive, simple and reliable one-step sandwich enzyme immunoassay (EIA) for the gamma-carboxylated form of osteocalcin (Gla-OC) has been developed using a monoclonal antibody. The minimum amount of Gla-OC detected by this EIA was approximately 0.2 ng/ml when a 10 microliter aliquot of the sample was used. The serum Gla-OC level in 30 healthy subjects was 3.6 +/- 2.19 ng/ml (mean +/- SD). A significant increase was seen in patients with chronic renal failure (20.3 +/- 4.60 ng/ml), atherosclerosis (8.3 +/- 4.94 ng/ml) and osteoporosis (10.1 +/- 4.60 ng/ml). The correlation between the values obtained by the sandwich EIA and competitive RIA methods was given by the linear regression equation, y = 2.896 + 0.759 chi, for which the correlation coefficient (r) was 0.815 (n = 58). This newly developed Gla-OC specific EIA may be useful for the diagnosis of metabolic bone disease and ectopic calcification. 相似文献