全文获取类型
收费全文 | 1324篇 |
免费 | 83篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 75篇 |
妇产科学 | 34篇 |
基础医学 | 134篇 |
口腔科学 | 66篇 |
临床医学 | 113篇 |
内科学 | 293篇 |
皮肤病学 | 15篇 |
神经病学 | 59篇 |
特种医学 | 23篇 |
外科学 | 277篇 |
综合类 | 39篇 |
预防医学 | 70篇 |
眼科学 | 62篇 |
药学 | 114篇 |
中国医学 | 7篇 |
肿瘤学 | 28篇 |
出版年
2023年 | 10篇 |
2022年 | 35篇 |
2021年 | 56篇 |
2020年 | 24篇 |
2019年 | 38篇 |
2018年 | 46篇 |
2017年 | 27篇 |
2016年 | 23篇 |
2015年 | 24篇 |
2014年 | 38篇 |
2013年 | 40篇 |
2012年 | 62篇 |
2011年 | 92篇 |
2010年 | 31篇 |
2009年 | 41篇 |
2008年 | 75篇 |
2007年 | 80篇 |
2006年 | 74篇 |
2005年 | 73篇 |
2004年 | 61篇 |
2003年 | 42篇 |
2002年 | 43篇 |
2001年 | 25篇 |
2000年 | 28篇 |
1999年 | 15篇 |
1998年 | 8篇 |
1996年 | 10篇 |
1995年 | 7篇 |
1993年 | 8篇 |
1992年 | 23篇 |
1991年 | 19篇 |
1990年 | 22篇 |
1989年 | 18篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1981年 | 8篇 |
1979年 | 14篇 |
1978年 | 7篇 |
1975年 | 10篇 |
1974年 | 14篇 |
1973年 | 15篇 |
1972年 | 8篇 |
1970年 | 6篇 |
1969年 | 7篇 |
1968年 | 7篇 |
1966年 | 6篇 |
排序方式: 共有1412条查询结果,搜索用时 15 毫秒
81.
Secondary ultrasound examination increases the sensitivity of the FAST exam in blunt trauma 总被引:3,自引:0,他引:3
Blackbourne LH Soffer D McKenney M Amortegui J Schulman CI Crookes B Habib F Benjamin R Lopez PP Namias N Lynn M Cohn SM 《The Journal of trauma》2004,57(5):934-938
INTRODUCTION: Approximately one third of stable patients with significant intra-abdominal injury do not have significant intraperitoneal blood evident on admission. We hypothesized that a delayed, repeat ultrasound study (Secondary Ultrasound--SUS) will reveal additional intra-abdominal injuries and hemoperitoneum. METHODS: We performed a prospective observational study of trauma patients at our Level I trauma center from April 2003 to December 2003. Patients underwent an initial ultrasound (US), followed by a SUS examination within 24 hours of admission. Patients not eligible for a SUS because of early discharge, operative intervention or death were excluded. All US and SUS exams were performed and evaluated by surgical/emergency medicine house staff or surgical attendings. RESULTS: Five hundred forty-seven patients had both an initial US and a SUS examination. The sensitivity of the initial US in this patient population was 31.1% and increased to 72.1% on SUS (p < 0.001) for intra-abdominal injury or intra-abdominal fluid. The specificity for the initial US was 99.8% and 99.8% for SUS. The negative predictive value was 92.0% for the initial US and increased to 96.6% for SUS (p = 0.002). The accuracy of the initial ultrasound was 92.1% and increased to 96.7% on the SUS (p < 0.002). No patient with a negative SUS after 4 hours developed clinically significant hemoperitoneum. CONCLUSION: A secondary ultrasound of the abdomen significantly increases the sensitivity of ultrasound to detect intra-abdominal injury. 相似文献
82.
Pervez A Zaman F Aslam A Petty S Murphy S Vachharajani T Abreo K;American Society of Diagnostic Interventional Nephrology 《Seminars in dialysis》2004,17(1):61-64
We retrospectively reviewed all subcutaneous single- and double-lumen port catheters (PCs) inserted by interventional nephrologists at our institution to determine the success rate, immediate and late complications, and functional life. From January 2000 to August 2002, 187 PCs were placed in 187 patients (42% males, 51% Caucasians, mean age 50 +/- 14 years). There were no immediate complications related to the procedure such as hemorrhage, pulmonary embolism, or pneumothorax. There were a total of 35,078 catheter-days of follow-up. Sixteen catheters were removed during the observation period: three because of infection, seven after completion of chemotherapy, and six for other reasons. The remaining PCs are either functioning or the patients have died. The initial success rate was 100%. Kaplan-Meier analysis showed a 30-day survival of 97% and a 1-year survival of 92%. Interventional nephrologists, who have adequate training in central venous tunneled cuffed catheter placements, can successfully place PCs, with excellent success and minimal complications. 相似文献
83.
Carey J Fahim A Munro M 《Journal of biomedical materials research. Part B, Applied biomaterials》2004,70(1):73-81
Cardiovascular catheterization is a common medical procedure. A single braided catheter with different rigidities at the proximal and distal ends can, if properly designed, provide the necessary control and flexibility and thus replace the current two-piece (external catheter/internal guidewire) system. An analytical model based on classical laminate plate theory was developed in order to predict the elastic properties of angle-plied, single-overlap two-dimensional fiber composite tubular braids, which are required for the determination of the axial, flexural, and torsional rigidities. In this work the analytical model has been used to design one-piece cardiovascular catheters with axial, flexural, and torsional rigidities similar to those values for existing two-piece catheters, thus validating the model as a tool for designing braided cardiovascular catheters. 相似文献
84.
Because of the potential importance of the lactational amenorrhea method (LAM) as a family-planning option in Egypt, we analyzed data from the 1995 Egyptian Demographic and Health Survey (EDHS) to study breastfeeding practices, use of contraception, reproductive history and sociodemographic factors for 5504 mothers with children under 3 years. According to the EDHS data, about 80% of Egyptian women breastfed for at least 6 months, and 40% breastfed for 15-18 months. Over half of breastfeeding mothers used no additional contraception. Thirty-six percent of mothers breastfeeding children younger than 6 months who reported using no additional contraception were exclusively breastfeeding and amenorrheic, but only 4% reported relying on breastfeeding for family planning. We also held eight focus group discussions with breastfeeding mothers from urban and rural Upper and Lower Egypt on their use of contraceptive methods, breastfeeding, lactational amenorrhea and LAM. Participants showed strong recognition of the contraceptive effects of breastfeeding but differed widely in their understanding of lactational infecundability and knowledge of LAM as a method. These results suggest that LAM would be widely acceptable to Egyptian women, but that an educational program about the method is needed. 相似文献
85.
Haji SA Brocks DC Fahim MM Asbell PA 《Journal of refractive surgery (Thorofare, N.J. : 1995)》2004,20(4):329-336
PURPOSE: We used EyeSys videokeratography to evaluate corneal shape changes induced by conductive keratoplasty, a procedure that utilizes radio frequency energy to alter corneal shape to correct hyperopia. METHODS: Follow-up data were available for 19 eyes (out of 24 eyes of 13 patients). Preoperative spherical hyperopia ranged from +0.75 to +3.25 D with astigmatism <0.75 D. Manifest refractive spherical equivalent refraction (MRSE), uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), topographical parameter predicted corneal acuity (PCA), corneal uniformity index (CU Index), regular astigmatism, total astigmatism, average simulated keratometry (Avg Sim K), effective refractive power, and asphericity were measured preoperatively and at 6 and 12 months postoperatively. RESULTS: Twelve months postoperatively, mean PCA, CU Index, and BSCVA were maintained at preoperative levels. Mean UCVA (LogMAR) improved from 0.53+/-0.21 to 0.10+/-0.19 (P<.05) with a mean MRSE change from +1.62+/-0.76 D to -0.06+/-0.84 D (P<.05) from preoperative to 12 months postoperative. Mean asphericity increased +0.044+/-0.24 D (P>.05), mean Avg Sim K increased 1.88+/-0.72 D (P<.05), mean effective refractive power increased 1.71+/-0.79 D (P<.05), mean cylinder (cycloplegic refraction) increased 0.19+/-0.36 D (P<.05), mean regular astigmatism increased 0.25+/-0.49 D (P>.05), and mean irregular astigmatism decreased 0.01+/-0.13 D (P>.05) from preoperative to 12 months after conductive keratoplasty. CONCLUSIONS: Avg Sim K and effective refractive power changes support the refractive results; 12-month postoperative maintenance of BSCVA, PCA, and CU Index suggest the procedure is safe. Conductive keratoplasty induced a slight regular astigmatism in some eyes, which decreased with time. The increase in mean corneal asphericity indicated possible induction of central and peripheral cornea changes. 相似文献
86.
Role of prophylactic scleral buckling in the management of retained intraocular foreign bodies 总被引:2,自引:0,他引:2
Purpose: To evaluate the role of prophylactic scleral buckling procedure with pars plana vitrectomy for the removal of retained intraocular foreign bodies (RIOFB) in the prevention of postoperative retinal detachment. Methods: In a prospective, clinical, controlled study, 28 patients with RIOFB without retinal detachment were randomly divided into two groups of 15 (group I) and 13 (group II) patients. All patients underwent a standard three‐port pars plana vitrectomy with foreign body removal. In addition to this standard procedure, patients assigned to group I had a 360° encircling scleral buckle placed at the time of surgery. Group II patients did not have any scleral buckling. All patients were followed up for an average period of 11.8 months. Both groups were comparable with respect to age, sex, duration of injury, nature of injury, and site, size and type of RIOFB. Results: The retinal detachment rate was found to be 6.6% in group I and 30.8% in group II (P = 0.24). Prophylactic scleral buckling reduced the risk of retinal detachment by 24% but this was not found to be statistically significant. Conclusion: Prophylactic scleral buckle placement with pars plana vitreous surgery for RIOFB may reduce the risk of late onset retinal detachment. A larger study would seem warranted. 相似文献
87.
Acute human self-poisoning with the N-phenylpyrazole insecticide fipronil--a GABAA-gated chloride channel blocker 总被引:3,自引:0,他引:3
Mohamed F Senarathna L Percy A Abeyewardene M Eaglesham G Cheng R Azher S Hittarage A Dissanayake W Sheriff MH Davies W Buckley NA Eddleston M 《Journal of toxicology. Clinical toxicology》2004,42(7):955-963
OBJECTIVE: Fipronil, a broad spectrum N-phenylpyrazole insecticide that inhibits GABAA-gated chloride channels, has been in use since the mid-1990s. A high affinity for insect compared to mammalian GABA receptors results in lower animal toxicity than other insecticides blocking this channel. To date, only two accidental cases of fipronil poisoning in humans have been published. CASE SERIES: We report seven patients with fipronil self-poisoning seen prospectively in Sri Lanka together with pharmacokinetics for four patients. Non-sustained generalized tonic-clonic seizures were seen in two patients (peak measured plasma fipronil concentrations 1600 and 3744 microg/L); both were managed with diazepam without complications. A patient with a peak measured plasma concentration of 1040 microg/L was asymptomatic throughout his stay. Plasma concentration was still high at discharge 3-4 days post-ingestion when the patients were well. Retrospective review of >1000 pesticide poisoning deaths since 1995 found only one death from fipronil-based products. In contrast to the good outcome of the above cases, this patient required intubation and ventilation and had continuous fits despite therapy with barbiturates and benzodiazepines. CONCLUSIONS: Our experience with prospectively observed patients suggests that fipronil poisoning is characterized by vomiting, agitation, and seizures, and normally has a favorable outcome. Management should concentrate on supportive care and early treatment of seizures. However, further experience is needed to determine whether increased susceptibility to fipronil or larger doses can produce status epilepticus. 相似文献
88.
Influence of stressors on the rewarding effects of alcohol in Wistar rats: studies with alcohol deprivation and place conditioning 总被引:1,自引:1,他引:0
Rationale and objectives Studies on laboratory animals have provided conflicting results regarding the actions of stressors on the rewarding effects of alcohol. In the present study, we first examined the effects of footshock or social defeat, given during deprivation, on the alcohol deprivation effect (ADE). We then tested the effects of stressors on place conditioning to alcohol, another technique used to measure drug reward.Methods Male Wistar rats were trained to drink 10% alcohol in a 24 h access, free-choice design and received intermittent footshock or defeat 5 times during a 2-week alcohol deprivation period, followed by 2 weeks of free access to alcohol. There were three such cycles. In the place conditioning studies, animals received footshock, defeat, or no stress immediately prior to conditioning sessions where they received alcohol (0.6 or 1.0 g/kg, IP) or vehicle injections.Results Alcohol intake of footshock-treated animals was significantly higher than that of controls following the first and second, but not the third period of alcohol deprivation and stress exposure. Defeat caused a smaller increase in alcohol intake that was significant only after the first deprivation and stress cycle. In the place conditioning studies, we found that either stressor blocked the place aversion induced by 1.0 g/kg alcohol.Conclusions These results demonstrate that stressors can modify the rewarding and aversive properties of alcohol, measured using two different paradigms. Footshock and defeat produced transient, but significant increases in the magnitude of ADE, while exposure to either stressor reduced the aversive effects of a high dose of alcohol measured using the place conditioning paradigm. 相似文献
89.
Perveen S Altaf W Vohra N Bautista ML Harper RG Wapnir RA 《Early human development》2002,69(1-2):15-23
BACKGROUND: The transport of essential trace elements from mother to fetus varies throughout gestation, and the role of transport proteins in the neonate and the mother may change during pregnancy. Magnesium, often used as tocolytic agent, may reach the fetus and appear in cord blood at higher than normal concentrations. AIMS: To determine cord blood plasma zinc, copper and magnesium concentrations, as well as plasma albumin in premature and full-term newborns, and correlate these values with those of maternal blood plasma at birth. Also, to examine whether cord blood plasma concentration of these elements varies with gestational age. SUBJECTS: The 35 mother-infant pairs included: 11 in the 38-42-week gestational age (GA), 9 in the 34-37-week GA, 11 in the 29-33-week GA group and 4 in the 24-28-week GA. Magnesium for tocolysis was given to five of the mothers in the 29-33-week GA cohort and two of the women giving birth at 24-28-week GA. RESULTS: Trend analysis showed that while cord plasma zinc decreased with GA at birth, the reverse was observed for copper. There were no differences with GA either in maternal plasma zinc or copper. However, maternal ceruloplasmin tended to decrease with GA (P=0.0174). Maternal and cord blood plasma magnesium exhibited a strong correlation (r=0.942, P<0.001), as well as between cord plasma magnesium and zinc (r=0.448, P<0.01). CONCLUSIONS: While the vigorous mother-to-fetus uphill zinc transfer is clear throughout the last trimester, copper remains in cord blood plasma at much lower concentrations than in the mother, suggesting that prematurity may place the newborn infant at a greater risk than the term infant to copper deficiency. This situation, together with a reduced synthesis in the fetus of the transport protein ceruloplasmin, creates another potential challenge in the nutritional support of the premature infant. 相似文献
90.