全文获取类型
收费全文 | 2602篇 |
免费 | 237篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 79篇 |
妇产科学 | 93篇 |
基础医学 | 403篇 |
口腔科学 | 63篇 |
临床医学 | 285篇 |
内科学 | 484篇 |
皮肤病学 | 25篇 |
神经病学 | 216篇 |
特种医学 | 138篇 |
外科学 | 361篇 |
综合类 | 64篇 |
一般理论 | 4篇 |
预防医学 | 248篇 |
眼科学 | 33篇 |
药学 | 164篇 |
2篇 | |
中国医学 | 3篇 |
肿瘤学 | 180篇 |
出版年
2022年 | 20篇 |
2021年 | 32篇 |
2020年 | 23篇 |
2019年 | 41篇 |
2018年 | 37篇 |
2017年 | 27篇 |
2016年 | 31篇 |
2015年 | 51篇 |
2014年 | 47篇 |
2013年 | 60篇 |
2012年 | 101篇 |
2011年 | 92篇 |
2010年 | 63篇 |
2009年 | 53篇 |
2008年 | 99篇 |
2007年 | 113篇 |
2006年 | 94篇 |
2005年 | 95篇 |
2004年 | 97篇 |
2003年 | 80篇 |
2002年 | 95篇 |
2001年 | 95篇 |
2000年 | 71篇 |
1999年 | 70篇 |
1998年 | 50篇 |
1997年 | 41篇 |
1996年 | 41篇 |
1995年 | 31篇 |
1994年 | 34篇 |
1993年 | 31篇 |
1992年 | 70篇 |
1991年 | 45篇 |
1990年 | 71篇 |
1989年 | 61篇 |
1988年 | 70篇 |
1987年 | 55篇 |
1986年 | 52篇 |
1985年 | 57篇 |
1984年 | 45篇 |
1983年 | 45篇 |
1982年 | 28篇 |
1981年 | 25篇 |
1980年 | 25篇 |
1979年 | 40篇 |
1978年 | 27篇 |
1976年 | 28篇 |
1975年 | 19篇 |
1972年 | 20篇 |
1971年 | 19篇 |
1969年 | 23篇 |
排序方式: 共有2857条查询结果,搜索用时 15 毫秒
1.
Margaret J Bowers Nick J Orr Si Dempsey H Denis Alexander 《Blood coagulation & fibrinolysis》2006,17(5):409-411
We present a case of Bernard Soulier syndrome in a 9-year-old boy caused by a novel genetic mutation. This child was shown to be homozygous for a single nucleotide deletion (c.1077delG) in the GP1BA gene not previously reported. Clinically, the boy has become refractory to platelet transfusions with both allo-antibodies and iso-antibodies and a massive transfusion requirement for ongoing haemorrhage. We describe the critical role that the blood product transfusion continues to play in the management of Bernard Soulier syndrome and discuss therapeutic options in these patients. 相似文献
2.
TF Leung WC Tsoi CK Li KW Chik MMK Shing PMP Yuen 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(6):705-777
We describe a 15-y-old girl with Fechtner-like syndrome, who is the first Chinese reported to have this rare syndrome. She presented with left homonymous hemianopia and neuroimaging revealed haemorrhage in both parietal and occipital lobes. Peripheral blood smear showed macrothrombocytopenia and intracytoplasmic inclusion bodies inside leucocytes. Thrombocytopenia and proteinuria responded to intravenous immunoglobulin and pulsed methylprednisolone. This case illustrates that life-threatening haemorrhage can occur in patients with Fechtner syndrome. Although there was no effective treatment reported in the literature, high dose steroid and immunoglobulin seemed to be useful in our patient. Our patient also had nephritic-nephrotic syndrome with renal insufficiency, which is unusual in adolescent female patients. 相似文献
3.
Computer simulations of bone remodeling in response to mechanical stresses can be used to understand normal growth and development of the skeleton or to predict the remodeling of bone in response to prosthetic devices. Using a previously derived bone maintenance theory, a technique for computing bone density distributions was applied to the proximal femur and tibia using two-dimensional, multiple-loading finite element models. The models initially represented solid, homogeneous structures. Using an iterative bone remodeling technique that relates bone apparent density to loading history, the internal distributions of apparent density and elastic modulus for the normal bones were predicted. The finite element models were then modified to represent bones in which porous-coated femoral surface replacements and tibial tray components had been implanted. The same iterative remodeling method was then applied to predict the distribution of bone around these components. The predicted bone density distributions for the natural femur and tibia agree with previously documented normal bone morphology. The predicted bone density distributions around various implanted prostheses were characteristic of the component under investigation and were consistent with clinical and experimental findings of other investigators. In the femoral head, stress shielding occurred underneath the metal surface replacement cup, resulting in lower densities in the femoral head. The addition of a central femoral cup fixation peg caused bone hypertrophy around the peg. In the tibia, the stress concentrations around the pegs also resulted in denser bone, with a concomitant decrease in bone density at more peripheral locations underneath the prosthetic tray. This remodeling technique has the potential to be an important tool in predicting the possible remodeling consequences of new implant design features. 相似文献
4.
Chronobiological characteristics of postoperative pain: Diurnal variation of both static and dynamic pain and effects of analgesic therapy 总被引:2,自引:1,他引:1
BACKGROUND: Previous postoperative investigations report morning peaks in analgesic administration. However, few studies have examined diurnal variation of both pain and analgesic consumption and little is known about dynamic pain in this context. METHODS: The diurnal pattern of postoperative pain is described using pain intensity and analgesic consumption data from a recently published hysterectomy trial. RESULTS: In the presence of patient-controlled analgesia with morphine, pain at 8 a.m. was significantly higher (P<0.05) than at noon, 4 p.m. or 8 p.m. on postoperative day one (for rest pain and pain evoked by sitting, forced expiration and cough) and on postoperative day two (for pain evoked by forced expiration and cough only). This temporal pattern was observed both with and without the co-administration of non-opioid analgesics (gabapentin and/or rofecoxib). Morphine use during the four hours preceding 8 a.m. on either postoperative day was not significantly lower than any of the other corresponding time intervals. CONCLUSIONS: Based on data from our post-hysterectomy analgesic clinical trial, static and dynamic pain in the morning appears to be more intense than pain later in the day. This pattern was observed in the presence of substantial nocturnal morphine use. Based on these and other previous observations, specifically designed investigations are needed to better characterize the clinical, neurohormonal and neurophysiological features of postoperative circadian pain variation - including pain during sleeping hours. If the above observations are replicated, future study of nocturnal sustained-release opioids as well as time-shifting the administration of non-opioid co-analgesic drugs to the very early morning may be warranted. 相似文献
5.
S Ajossa S Guerriero A M Paoletti M Orrù G B Melis 《Ultrasound in obstetrics & gynecology》2002,20(3):276-280
OBJECTIVE: To determine whether hyperinsulinemia has a negative effect on uterine blood supply in patients with polycystic ovary syndrome (PCOS). METHODS: Sixty-three patients with normal body mass index were included prospectively in the study: 48 had clinical and hormonal features of PCOS and 15 were normo-ovulatory. All patients underwent Doppler flow measurement of the uterine artery, and determination of serum concentrations of luteinizing hormone, follicle stimulating hormone, prolactin, estradiol, androgens, insulin and C-peptide during the early follicular phase of the menstrual cycle. The 48 PCOS-patients were divided into two groups according to the pulsatility index (PI) value of the uterine artery: Group 1, PI < 3; Group 2, PI >or= 3 and the groups were compared. RESULTS: The mean PI of the uterine artery (3.01 +/- 1.0 vs. 1.93 +/- 0.3, respectively) and fasting levels of insulin (50.9 +/- 9.3 vs. 40.3 +/- 10.9) and C-peptide (366.9 +/- 118.4 vs. 243.6 +/- 120.3) of PCOS-patients were significantly higher than those of the control group. No correlation was found between insulinemia and C-peptide and PI of the uterine artery and no significant difference was found in insulin and C-peptide levels among the two groups of PCOS-affected patients. Only the serum level of dehydroepiandrosterone sulfate was significantly higher in Group 2, and a direct correlation was found between PI values of the uterine artery and DHEAS plasma levels. CONCLUSION: Insulin and C-peptide do not seem to interfere with uterine perfusion in PCOS-affected patients. 相似文献
6.
Bruce F. Waller Charles M. Orr James Van Tassel Thomas Peters Edward Fry James Hermiller Larry D. Grider 《Clinical cardiology》1997,20(1):67-74
Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effect on the site of obstruction has been termed “remodeling.” Part V of this six-part series focuses on remodeling effects of balloon angioplasty on obstructed young (≤ 1 year) and old (> 1 year) saphenous vein bypass grafts. 相似文献
7.
Cerebral radioprotection by pentobarbital: dose-response characteristics and association with GABA agonist activity 总被引:5,自引:0,他引:5
Pentobarbital reduces cerebral radiation toxicity; however, the mechanism of this phenomenon remains unknown. As an anesthetic and depressant of cerebral metabolism, pentobarbital induces its effects on the central nervous system by stimulating the binding of gamma-aminobutyric acid (GABA) to its receptor and by inhibiting postsynaptic excitatory amino acid activity. The purpose of this study is to investigate the role of these actions as well as other aspects of the radioprotective activity of pentobarbital. Fischer 344 rats were separated into multiple groups and underwent two dose-response evaluations. In one set of experiments to examine the relationship of radioprotection to pentobarbital dose, a range of pentobarbital doses (0 to 75 mg/kg) were given intraperitoneally prior to a constant-level radiation dose (70 Gy). In a second series of experiments to determine the dose-response relationship of radiation protection to radiation dose, a range of radiation doses (10 to 90 Gy) were given with a single pentobarbital dose (60 mg/kg intraperitoneally). Further groups of animals were used to evaluate the importance of the timing of pentobarbital administration, the function of the (+) and (-) isomers of pentobarbital, and the role of an alternative GABA agonist (diazepam). In addition, the potential protective effects of alternative methods of anesthesia (ketamine) and induction of cerebral hypometabolism (hypothermia) were examined. Enhancement of survival time from acute radiation injury due to high-dose single-fraction whole-brain irradiation was maximal with 60 mg/kg of pentobarbital, and occurred over the range of all doses examined between 30 to 90 Gy. Protection was seen only in animals that received the pentobarbital before irradiation. Administration of other compounds that enhance GABA binding (Saffan and diazepam) also significantly enhanced survival time. Ketamine and hypothermia were without protective effect. Protection from acute radiation-induced mortality by pentobarbital in the rat model is a reproducible phenomenon and is associated with the GABA agonistic activity of the compound. This property of GABA agonists offers the potential for a novel approach to enhancement of the efficacy of radiation therapy in the treatment of brain tumors. 相似文献
8.
A Y Shalev S P Orr T Peri S Schreiber R K Pitman 《Archives of general psychiatry》1992,49(11):870-875
Orbicularis oculi (eye blink) electromyogram, skin conductance, and heart rate responses to 15 consecutive 95-dB, 500-millisecond, 1000-Hz tones with 0-millisecond rise and fall times were measured in 14 patients with posttraumatic stress disorder, 14 patients with other anxiety disorders, 15 mentally healthy subjects with past traumatic experiences, and 19 mentally healthy subjects with no trauma history. The patients with posttraumatic stress disorder showed significantly larger skin conductance and heart rate responses and a trend toward larger electromyogram responses to the tones than every other group. These effects were not explained by subjective anxiety, resting physiologic arousal, physiologic arousal preceding the tone trials, or initial physiologic responsivity. The group with posttraumatic stress disorder was the only one that failed to show habituation of skin conductance responses. 相似文献
9.
10.