全文获取类型
收费全文 | 38794篇 |
免费 | 2564篇 |
国内免费 | 139篇 |
专业分类
耳鼻咽喉 | 412篇 |
儿科学 | 860篇 |
妇产科学 | 757篇 |
基础医学 | 4626篇 |
口腔科学 | 988篇 |
临床医学 | 4043篇 |
内科学 | 8133篇 |
皮肤病学 | 408篇 |
神经病学 | 3260篇 |
特种医学 | 1294篇 |
外国民族医学 | 1篇 |
外科学 | 6683篇 |
综合类 | 541篇 |
一般理论 | 26篇 |
预防医学 | 3143篇 |
眼科学 | 1197篇 |
药学 | 2463篇 |
中国医学 | 39篇 |
肿瘤学 | 2623篇 |
出版年
2023年 | 177篇 |
2022年 | 304篇 |
2021年 | 713篇 |
2020年 | 437篇 |
2019年 | 634篇 |
2018年 | 770篇 |
2017年 | 555篇 |
2016年 | 652篇 |
2015年 | 768篇 |
2014年 | 1119篇 |
2013年 | 1710篇 |
2012年 | 2457篇 |
2011年 | 2550篇 |
2010年 | 1447篇 |
2009年 | 1356篇 |
2008年 | 2327篇 |
2007年 | 2395篇 |
2006年 | 2396篇 |
2005年 | 2579篇 |
2004年 | 2488篇 |
2003年 | 2279篇 |
2002年 | 2168篇 |
2001年 | 284篇 |
2000年 | 222篇 |
1999年 | 368篇 |
1998年 | 513篇 |
1997年 | 412篇 |
1996年 | 348篇 |
1995年 | 343篇 |
1994年 | 279篇 |
1993年 | 264篇 |
1992年 | 218篇 |
1991年 | 193篇 |
1990年 | 159篇 |
1989年 | 155篇 |
1988年 | 148篇 |
1987年 | 160篇 |
1986年 | 148篇 |
1985年 | 178篇 |
1984年 | 264篇 |
1983年 | 259篇 |
1982年 | 370篇 |
1981年 | 332篇 |
1980年 | 308篇 |
1979年 | 153篇 |
1978年 | 194篇 |
1977年 | 201篇 |
1976年 | 191篇 |
1975年 | 149篇 |
1973年 | 149篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
OBJECTIVE: Based on recent safety and efficacy data, combined with the known pharmacokinetic parameters of aminoglycosides in the newborn, once-daily gentamicin should be preferable to the many other dosing regimens currently in use. Although there are growing data to support its use in term newborns, experience with preterm infants is more limited. In our Neonatal Intensive Care Unit, we experienced difficulties regarding complicated dosing regimens, actual dosing errors, and the tendency to check trough and peak levels around the third dose for infants receiving only a 48 hour course. Therefore, we conducted a quality improvement initiative in which we developed and tested a clinical practice guideline for the use of once-daily gentamicin for preterm and term infants that we hoped would yield trough and peak levels in our target range. METHODS: We combined a review of the published English language literature with pharmacokinetic analysis of our own data prior to initiation of this new regimen to design the following dosing regimen: <35 weeks gestation: 3 mg/kg q 24 hours, > or =35 weeks gestation: 4 mg/kg q 24 hours. Our goal serum levels were a trough < or =2 microg/ml and a peak between 6 and 12 microg/ml. We collected and analyzed trough and peak levels from all infants receiving this dosing regimen in the first week of life for at least 72 hours between 3/1/99 and 12/31/00. RESULTS: In total, 214 babies met our inclusion criteria, 75 of whom were <35 weeks gestation. 100% of babies of all gestational ages had a nontoxic trough level. For infants <35 weeks gestation, 79% had a therapeutic peak level, with a mean value of 6.8 microg/ml. For infants of at least 35 weeks gestation, 93% had a therapeutic peak level, with a mean value of 8.4 microg/ml. 92% of nontherapeutic peaks were too low. CONCLUSION: This study of once-daily gentamicin represents the largest sample size of pre-term infants published to date. The proposed regimen is simple and yields a high proportion of desirable levels. We recommend it for use in preterm and term newborns. 相似文献
43.
Thromboembolic and inflammatory complications of knee joint alloplasty with cemented endoprostheses]
Edward Golec Sebastian Nowak Jaros?aw Wi?niowski Maciej Piatkowski 《Chirurgia narzadów ruchu i ortopedia polska》2004,69(5):315-319
In the presented paper the authors evaluate the long-term results of treatment for inflammatory and thromboembolic complications in knee joint alloplasty with cemented endoprostheses. The clinical material spanning the years 1998-2003 are 15 patients with analysed complications, it determine 9% of all operated. They have evaluated achieved results using the HSS knee rating scale in their own modification. As far as the authors are concerned, venographic examination is a prerequisite for appropriate care of the patients following knee joint alloplasty who might have deep venous thrombosis. It is necessary to provide similar treatment when developing infections are suspected in the perioperative period and in cases of late infections. Consequently, antibiotic therapy and a possible quick bacteriological checkup for healing a postoperative wound is a prerequisite for successful treatment. Achieved results induce statement, that thromboembolic and inflammatory complications caused at most operated chronic vein insufficiency, deficit of range of motion at operated joint and gait insufficiency. Thromboembolic complications was always related with inflammation of knee joint alloplasty in our own material. 相似文献
44.
Edward J Boland Mary MacDougall David L Carnes Sabine H Dickens 《Dental materials》2006,22(4):338-345
Recently, a resin-based calcium phosphate cement (RCPC) has been reported as a remineralizing pulp-capping or lining cement. RCPC consists mainly of tetracalcium and dicalcium phosphates, ethoxylated bisphenol A dimethacrylate and pyromellitic glycerol dimethacrylate monomers and photo- and chemical initiators. OBJECTIVES: Here, the cytotoxic effects of RCPC were evaluated. The hypothesis was that RCPC induced only minor cytotoxic response in immortalized murine odontoblast and pulp cells, comparable to that produced by similar dimethacrylates due to unpolymerized dimethacrylate monomer present after curing. METHODS: Cytotoxicity was determined following the changes in cell succinate dehydrogenase activity after 24 h exposure to the cement components and after a 24 h recovery period. A fourfold range of concentrations was tested of the monomers, the eluate of cured RCPC leached in Dulbecco's modified Eagle's medium, and crushed cured cement in dimethyl sulfoxide. RESULTS: The monomers themselves had cytotoxicities similar to those reported for other dimethacrylates, although they are significantly less toxic than Bis-GMA. Differential cell sensitivity was demonstrated, with the pulp cells having greater sensitivity to the unpolymerized monomer than the odontoblast-like cells. The leached components have cytotoxicity similar to that of the free monomers. The crushed material demonstrated no apparent cytotoxicity at the dilutions tested. SIGNIFICANCE: These data demonstrate that RCPC has an in vitro cytotoxicity that is comparable to other materials containing dimethacrylate monomers and suggest that the material may be suitable for use in dental restorations. The data also indicate that the pulp cells appear more sensitive to dimethacrylates than the odontoblasts. 相似文献
45.
46.
Jeffrey N Baldwin David M Scott Sangeeta Agrawal Jean K Bartek R Ellen Davis-Hall Thomas P Reardon Edward M DeSimone 《Substance Abuse》2006,27(3):27-37
Alcohol and other drug (AOD) use behaviors of health professions students (HPS) were assessed by surveying both university-based HPS and other nursing programs in a Midwestern state in 1999. Response was 2,646 (56.4%) of surveyed students. Family history of alcohol-related and drug-related problems were reported by 39.8% and 13.9%, respectively, with 42.6% of respondents reporting one or both. Among nursing respondents, 48.1%, 19.2% and 51.1%, respectively, reported family problems with alcohol, drugs, or one or both. Past-year alcohol use was comparable to undergraduate college students (UCS) nationally (83%); heavy drinking, tobacco and recreational drug use by HPS were lower. Past year drug use was highest among medical students. Marijuana was the predominant illicit drug; medical students and males most often reported use. Health professions educational systems should proactively address student AOD prevention, education and assistance needs. 相似文献
47.
The state of pregnancy is an immunological enigma during which the body must prevent rejection of the antigenically foreign fetus while at the same time maintain sufficient maternal host defense mechanisms to combat infection. Although most studies on the immunology of pregnancy focus on immune suppression, several studies have shown an increase in nonspecific host defense, which is postulated to be a compensatory mechanism for decreased specific immunity during pregnancy. Studies in this laboratory have shown that monocyte surface FcγRI (CD64) and FcγRII (CD32) expression progressively increase throughout pregnancy, while surface MHC class II expression remains unchanged. Functional studies revealed that the number of phagocytic monocytes which could be isolated from pregnant women was increased. These cells exhibited an increased capacity to ingest IgG-opsonized human erythrocytes. This study shows for the first time that monocyte surface FcγR expression and FcγR-mediated functions are increased during pregnancy. These results support the hypothesis that nonspecific immunity as represented by FcγR expression and function is increased during pregnancy. 相似文献
48.
Brigden Geoffrey Zanelli Giussepe Lahiri Avijit Raftery Edward 《European journal of nuclear medicine and molecular imaging》1990,16(11):795-799
A new, single bolus method of in vivo blood pool imaging using a technetium Tc99m phosphine isocyanide complex (DEPIC) which binds to pre-albumin was evaluated in volunteers (n=4) and patients (n=20). DEPIC was assessed for its safety and possible drug interactions. Its duration of action and quality of ventriculography were compared with imaging using standard in vivo red cell labelling (PYP) during two 3-h scanning periods 1 week apart. DEPIC had a mean plasma halflife of 3.3 h. The count rate over the left ventricle was initially 42% higher with DEPIC than with PYP. However, removal of DEPIC by the liver resulted in equivalent count rates by 1 h, and by 3 h PYP count rates were 22% higher than DEPIC. Immediately post injection mean (SD) difference in the left ventricular ejection fraction between the two methods was 2.4% (7.7%). Satisfactory DEPIC scans were obtained up to 2 h post injection, but by 3 h there was a mean difference of 13% (11.3%). DEPIC was found to be a safe alternative to red all labelling for blood pool angiography, suitable for routine work. The single bolus methodology and high initial count rates offer improved efficiency and a capability for truly emergency scanning. 相似文献
49.
50.