全文获取类型
收费全文 | 42728篇 |
免费 | 3865篇 |
国内免费 | 61篇 |
专业分类
耳鼻咽喉 | 450篇 |
儿科学 | 1447篇 |
妇产科学 | 1290篇 |
基础医学 | 5617篇 |
口腔科学 | 837篇 |
临床医学 | 5542篇 |
内科学 | 8424篇 |
皮肤病学 | 562篇 |
神经病学 | 3327篇 |
特种医学 | 1405篇 |
外国民族医学 | 9篇 |
外科学 | 5092篇 |
综合类 | 830篇 |
一般理论 | 56篇 |
预防医学 | 5212篇 |
眼科学 | 979篇 |
药学 | 2816篇 |
中国医学 | 46篇 |
肿瘤学 | 2713篇 |
出版年
2022年 | 275篇 |
2021年 | 597篇 |
2020年 | 386篇 |
2019年 | 661篇 |
2018年 | 741篇 |
2017年 | 625篇 |
2016年 | 625篇 |
2015年 | 648篇 |
2014年 | 998篇 |
2013年 | 1597篇 |
2012年 | 2187篇 |
2011年 | 2375篇 |
2010年 | 1175篇 |
2009年 | 1083篇 |
2008年 | 2114篇 |
2007年 | 2163篇 |
2006年 | 2100篇 |
2005年 | 2015篇 |
2004年 | 1906篇 |
2003年 | 1836篇 |
2002年 | 1805篇 |
2001年 | 1181篇 |
2000年 | 1212篇 |
1999年 | 1047篇 |
1998年 | 449篇 |
1997年 | 412篇 |
1996年 | 420篇 |
1995年 | 365篇 |
1994年 | 355篇 |
1993年 | 337篇 |
1992年 | 947篇 |
1991年 | 928篇 |
1990年 | 852篇 |
1989年 | 784篇 |
1988年 | 697篇 |
1987年 | 705篇 |
1986年 | 705篇 |
1985年 | 690篇 |
1984年 | 570篇 |
1983年 | 446篇 |
1982年 | 359篇 |
1981年 | 303篇 |
1980年 | 265篇 |
1979年 | 532篇 |
1978年 | 325篇 |
1976年 | 279篇 |
1975年 | 318篇 |
1974年 | 355篇 |
1973年 | 293篇 |
1972年 | 273篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
71.
B A Barut L I Zon M K Cochran S R Paul D Chauhan A Mohrbacher J Fingeroth K C Anderson 《Leukemia research》1992,16(10):951-959
The role of interleukin 6 (IL-6) in the growth of five multiple myeloma-derived cell lines was characterized. The U266 and RPMI 8226 cell lines demonstrated increased DNA synthesis when cultured with exogenous IL-6, expressed IL-6 cell surface receptors (IL-6Rs) and expressed mRNA for IL-6R. However, these cells did not secrete detectable IL-6 protein, and a neutralizing antibody to IL-6 did not inhibit their growth. Three other myeloma-derived cell lines ARH-77, IM-9 and HS-Sultan did not respond to exogenous IL-6, secrete IL-6 or express cell surface IL-6Rs. The IL-6 responsive cell lines bore late B-cell surface antigens (Ags), CD38 and PCA-1, whereas those lines which were non-IL-6 responsive strongly expressed B1 (CD20) and B4 (CD19) Ags, representing earlier stages in B-cell differentiation. Finally, the two IL-6 responsive cell lines did not express Epstein-Barr virus (EBV) proteins; in contrast, EBV encoded proteins typically expressed during latency could be detected in the three non-IL-6 responsive lines, confirming infection with virus. These studies clarify the heterogeneity observed in the myeloma cell line phenotype and biology and suggest that the U266 and RPMI 8226 cell lines, which express IL-6 cell surface receptors and are IL-6 responsive, may be useful for further study of IL-6 signal transduction in and related IL-6 mediated growth of myeloma in vivo. In contrast, those cell lines which are IL-6-independent provide a model for further study of EBV transformation and IL-6-dependent growth mechanisms in malignancy. 相似文献
72.
Imad Ghorayeb MD PhD Anderson Loundou PhD Pascal Auquier MD Yves Dauvilliers MD PhD Bernard Bioulac MD PhD François Tison MD PhD 《Movement disorders》2007,22(11):1567-1572
To determine the prevalence of excessive daytime sleepiness (EDS) and that of dozing and sudden onset of sleep episodes (SOS) while driving in ambulatory patients with Parkinson's disease (PD) in France, a national sample of private and public neurologists was asked to recruit the first 10 consecutive nondemented PD patients. Each patient completed a questionnaire including the Epworth Sleepiness Scale (ESS) and the likelihood of dozing off and experiencing SOS episodes behind the wheel. Clinical and demographic data were collected. One thousand six hundred and twenty‐five patients with PD were included in the survey. Twenty‐nine percent of the patients suffered from EDS (ESS score ≥10) but only 0.8% declared a high chance of dozing while driving and 0.5% reported totally unpredictable SOS episodes while driving. Risk factors for EDS were male gender, reduced activity of daily living, and a high daily levodopa equivalent dosage. Risk factors for SOS episodes while driving were an ESS score ≥10, male gender, and low Hoehn and Yahr staging. EDS is common in ambulatory patients with PD and is a major risk factor for dozing and for SOS episodes behind the wheel in patients who drive. © 2007 Movement Disorder Society 相似文献
73.
Valery L Feigin Craig S Anderson Anthony Rodgers Neil E Anderson Alistair J Gunn 《Journal of clinical neuroscience》2002,9(5):502-507
Current treatment of acute stroke remains unsatisfactory. This review presents experimental and clinical data which suggest that mild induced hypothermia could be a potent and practicable neuroprotective treatment of acute ischaemic stroke and intracerebral haemorrhage. Hypothermia, if proven to be safe, effective and widely practicable in patients with acute stroke, could have an enormous positive impact on reducing the burden of stroke worldwide. Critical issues that will need to be considered in a well designed randomised controlled trial of induced hypothermia in acute stroke patients are discussed. 相似文献
74.
Reduced blood clearance and increased urinary excretion of N-nitrosodimethylamine in patas monkeys exposed to ethanol or isopropyl alcohol. 总被引:1,自引:0,他引:1
L M Anderson R Koseniauskas E S Burak T J Moskal C T Gombar J M Phillips E B Sansone S Keimig P N Magee J M Rice 《Cancer research》1992,52(6):1463-1468
Low concentrations of N-nitrosodimethylamine are metabolized in rodent and human liver by cytochrome P450IIE1, an activity competitively inhibitable by ethanol. In rodents coadministration of ethanol with N-nitrosodimethylamine results in increased tumorigenicity in extrahepatic organs, probably as a result of reduced hepatic clearance. To test this concept in a primate, the effects of ethanol cotreatment on the pharmacokinetics of N-nitrosodimethylamine were measured in male patas monkeys. Ethanol, 1.2 g/kg given p.o. before i.v. N-nitrosodimethylamine (1 mg/kg) or concurrently with an intragastric dose resulted in a 10-50-fold increase in the area under the blood concentration versus time curves and a 4-13-fold increase in mean residence times for N-nitrosodimethylamine. Isopropyl alcohol, 3.2 g/kg 24 h before N-nitrosodimethylamine, also increased these parameters 7-10-fold; this effect was associated with persistence of isopropyl alcohol and its metabolic product acetone, both IIE1 inhibitors, in the blood. While no N-nitrosodimethylamine was detected in expired air, trace amounts were found in urine. Ethanol and isopropyl alcohol pretreatment increased the maximum urinary N-nitrosodimethylamine concentration 15-50-fold and the percentage of the dose excreted in the urine by 100-800-fold. Thus ethanol and isopropyl alcohol greatly increase systemic exposure of extrahepatic organs to N-nitrosodimethylamine in a primate. 相似文献
75.
Samuel B Adams Paul R Herz Debra L Stamper Mark J Roberts Stephane Bourquin Nirlep A Patel Karl Schneider Scott D Martin Sonya Shortkroff James G Fujimoto Mark E Brezinski 《Journal of orthopaedic research》2006,24(4):708-715
The objective of this study was to develop and verify a new technique for monitoring the progression of osteoarthritis (OA) by combining a rat model with the imaging modality optical coherence tomography (OCT). Time-sequential, in vivo, OCT imaging was performed on the left femoral condyles of 12 Wistar rats following sodium-iodoacetic acid-induced OA progression. The right femoral condyles (untreated) were also imaged and served as controls. Imaging was performed on days 0, 10, 20, 30, and 60 with an OCT system capable of acquiring images at four frames per second and an axial resolution of 5 microm. Progressive changes were analyzed using an OA scoring system. OCT successfully identified progressive cartilage degeneration as well as alteration of the cartilage/bone interface. Significant changes to both of these structures were observed in the sodium-iodoacetic acid-injected condyles. Structural changes detected with OCT were confirmed histologically. OCT in combination with a well-known model used in arthritis research represents a powerful tool for following degenerative joint disease progression in a given animal by detecting changes to the cartilage/bone interface and articular cartilage. 相似文献
76.
C V Smith J C Anderson A Matamoros W F Rayburn 《Journal of ultrasound in medicine》1992,11(9):465-467
Transvaginal ultrasonography has been proposed as a reliable method of assessing dimensions of the cervix. The purpose of the current investigation was to establish normative data for cervical width and length during pregnancy. This information may be helpful in predicting patients at risk for preterm birth. A transvaginal 5 or 7.5 MHz transducer was used on 132 consecutive low-risk pregnant women undergoing evaluation for gestational dating purposes. Even in cases of patient obesity or an empty bladder, high resolution was possible and permitted cervical measurement in all but one case. The external cervical width at the vaginal fornices was found to increase with advancing gestation (R = 0.512, P < 0.005). The cervical length from internal os to external os was found not to change with advancing gestation (R = 0.11, P = 0.30). Using these normative data, investigation is recommended to determine whether measuring cervical width and length is useful in predicting preterm labor and delivery. 相似文献
77.
J J Zachwieja D L Costill G C Beard R A Robergs D D Pascoe D E Anderson 《International journal of sport nutrition》1992,2(3):239-250
To determine the effect of a carbonated carbohydrate (CHO) drink on gastric function and exercise performance, eight male cyclists completed four 120-min bouts of cycling. Each bout consisted of a 105-min ride at 70% VO2max followed by a 15-min self-paced performance ride. During each trial, one of four test solutions was ingested: carbonated CHO (C-10%), noncarbonated CHO (NC-10%), carbonated non-CHO (C), and noncarbonated non-CHO (NC). Following the performance ride, the subjects had their stomach contents removed by aspiration. There were no significant differences in gastric emptying (GE) except for Trial C-10%, which averaged 13.3% less than NC. However, there was no difference in the perception of gastrointestinal comfort between this trial and any other. Average power output during the performance ride was not significantly different between carbonated and noncarbonated trials, or between CHO-fed and no-CHO trials; however, the subjects worked at a greater intensity when fed CHO. Finally, acid base status did not change when a carbonated drink was ingested. This indicates that adding carbonation to a sport drink does not significantly alter gastric function, the perception of GI comfort, or exercise performance. 相似文献
78.
Influence of murine mast cell growth factor (c-kit ligand) on colony formation by mouse marrow hematopoietic progenitor cells. 总被引:7,自引:0,他引:7
H E Broxmeyer G Hangoc S Cooper D Anderson D Cosman S D Lyman D E Williams 《Experimental hematology》1991,19(2):143-146
Purified natural and recombinant murine mast cell growth factor (MGF, a c-kit ligand) were evaluated alone and in combination with other cytokines for effects in vitro on colony formation by multipotential (CFU-GEMM), erythroid (BFU-E) and granulocyte-macrophage (CFU-GM) progenitor cells from BDF1 mouse bone marrow. Both preparations stimulated Epo-dependent CFU-GEMM and enhanced Epo-dependent BFU-E colony numbers and size. MGF had some stimulating activity for CFU-GM. When used in combination with plateau concentrations of pokeweed mitogen mouse spleen cell conditioned medium or granulocyte-macrophage colony stimulating factor (CSF), MGF enhanced in greater than additive fashion colony formation by CFU-GM. MGF also enhanced the size of colonies formed, an enhancement greatest for colonies containing granulocytes and macrophages. MGF did not enhance Macrophage-CSF stimulated colony numbers or size. MGF seems to be an early acting cytokine with preferential effects on the growth of more immature hematopoietic progenitor cells. 相似文献
79.
80.
T. A. Briscoe D. Anderson O. S. Usifo G. S. Cooper 《Journal of the National Medical Association》1997,89(11):728-730
A retrospective analysis was conducted to determine the effects of metformin on glycosylated hemoglobin (HbA1c), body weight, and adverse events in an African-American population. Thirty-six patients who were receiving combination therapy with metformin and either a sulfonylurea or insulin were identified from a hospital pharmacy database. Nineteen patients met the criteria for efficacy analysis. The combination of metformin with either a sulfonylurea or insulin resulted in a decrease of the average HbA1c from a baseline of 10.07% to 7.92% (delta = 2.15%). The effect of combination therapy on weight was variable; however, twice as many patients lost weight compared with those who gained weight. Metformin appeared to be well-tolerated, with gastrointestinal symptoms being the most commonly reported adverse events. 相似文献