全文获取类型
收费全文 | 3216篇 |
免费 | 159篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 172篇 |
妇产科学 | 194篇 |
基础医学 | 264篇 |
口腔科学 | 119篇 |
临床医学 | 270篇 |
内科学 | 775篇 |
皮肤病学 | 48篇 |
神经病学 | 124篇 |
特种医学 | 200篇 |
外科学 | 523篇 |
综合类 | 179篇 |
预防医学 | 122篇 |
眼科学 | 68篇 |
药学 | 129篇 |
中国医学 | 43篇 |
肿瘤学 | 127篇 |
出版年
2023年 | 17篇 |
2022年 | 31篇 |
2021年 | 56篇 |
2020年 | 44篇 |
2019年 | 49篇 |
2018年 | 67篇 |
2017年 | 56篇 |
2016年 | 93篇 |
2015年 | 105篇 |
2014年 | 131篇 |
2013年 | 171篇 |
2012年 | 239篇 |
2011年 | 227篇 |
2010年 | 175篇 |
2009年 | 167篇 |
2008年 | 179篇 |
2007年 | 193篇 |
2006年 | 186篇 |
2005年 | 178篇 |
2004年 | 149篇 |
2003年 | 131篇 |
2002年 | 91篇 |
2001年 | 79篇 |
2000年 | 49篇 |
1999年 | 61篇 |
1998年 | 53篇 |
1997年 | 66篇 |
1996年 | 55篇 |
1995年 | 40篇 |
1994年 | 33篇 |
1993年 | 33篇 |
1992年 | 13篇 |
1991年 | 9篇 |
1990年 | 12篇 |
1989年 | 27篇 |
1988年 | 20篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 10篇 |
1984年 | 11篇 |
1983年 | 4篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1980年 | 11篇 |
1979年 | 3篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 2篇 |
1958年 | 4篇 |
1957年 | 2篇 |
排序方式: 共有3406条查询结果,搜索用时 562 毫秒
31.
Since exogenous hemin has been shown to exert a variety of stimulatory effects on erythroid cells, including the augmentation of hemoglobin synthesis, we determined its effect on early stages of erythroid development by employing clonal cells assays. The addition of hemin at a concentration of 2 X 10(-4) M to cultures of normal murine marrow substantially increased the observed number of primitive BFU-E, which was in contrast to its lack of an effect on more mature erythroid colony-forming cells. This cell-specific enhancement of primitive BFU-E resulted in marrow frequencies equivalent to or exceeding those reported in the presence of "burst-promoting activity." In the presence of hemin, the number of BFU-E was also observed to be linearly related to the number of cells plated at very low plating densities, and the cell titration curve was observed to extrapolate to the origin. The evidence suggests that hemin may be a primary growth regulator of early developmental stages of erythroid progenitor cells. 相似文献
32.
Kazancioğlu R Sever MS Yüksel-Onel D Eraksoy H Yildiz A Celik AV Kayacan SM Badur S 《Clinical transplantation》2000,14(1):61-65
BACKGROUND: Streptococcus pneumoniae, a common pathogen leading to pneumonia, is a cause of morbidity and mortality in immunosuppressed patients. Vaccination against this agent can be recommended for immunosuppressed patients, including those with chronic renal failure, nephrotic syndrome and renal transplant recipients; however, a diminished immune response and loss of protective antibodies have been observed. PATIENTS AND METHODS: In our prospective study, the efficacy and side effects of polyvalent pneumococcal vaccination were investigated in renal transplant recipients. A total of 21 patients (6 female, 15 male) with well-functioning renal allografts, who had transplant surgery at least 2 months before, were included in the study. The patients were stratified according to the immunosuppressive protocol and 8 received double, while 13 received triple, immunosuppressive agents. After obtaining basal serum samples, all cases were vaccinated with the 0.5 mL intramuscular administration of polyvalent polysaccharide pneumococcal vaccine (Pneumo 23 Pasteur Merieux, lot No: K 1131). RESULTS: Following a mean of 6 wk in all patients and also a mean of 12 wk in 12 patients, serum samples were again obtained to measure pneumococcal antibodies. Antibody titers following 6 and 12 wk of vaccination were significantly higher, as compared with basal values in all patients, except one. These titers did not show any statistically significant difference between double and triple therapies. There was no significant difference between the 12th and 6th wk postvaccination antibody titers. No systemic or local adverse effects were observed. CONCLUSION: Pneumococcal vaccination is safe and effective in patients with well-functioning renal allografts, at least in the short term. This vaccination policy may be useful for preventing invasive pneumococcal disease in immunosuppressed patients. 相似文献
33.
Assessment of the mutagenicity of dichloroacetic acid in lacI transgenic B6C3F1 mouse liver 总被引:2,自引:0,他引:2
Dichloroacetic acid (DCA) is a chlorination byproduct found in finished
drinking water. When administered in drinking water this chemical has been
shown to produce hepatocellular adenomas and carcinomas in B6C3F1 mice over
the animal's lifetime. In this study, we investigated whether mutant
frequencies were increased in mouse liver using treatment protocols that
yielded significant tumor induction. DCA was administered continuously at
either 1.0 or 3.5 g/l in drinking water to male transgenic B6C3F1 mice
harboring the bacterial lacI gene. Groups of five or six animals were
killed at 4, 10 or 60 weeks and livers removed. At both 4 and 10 weeks of
treatment, there was no significant difference in mutant frequency between
the treated and control animals at either dose level. At 60 weeks, mice
treated with 1.0 g/l DCA showed a 1.3-fold increase in mutant frequency
over concurrent controls (P = 0.05). Mice treated with 3.5 g/l DCA for 60
weeks had a 2.3-fold increase in mutant frequency over the concurrent
controls (P = 0.002). The mutation spectrum recovered from mice treated
with 3.5 g/l DCA for 60 weeks contained G:C-->A:T transitions (32.79%)
and G:C-->T:A transversions (21.31%). In contrast, G:C-->A:T
transitions comprised 53.19% of the recovered mutants among control
animals. Although only 19.15% of mutations among the controls were at T:A
sites, 32.79% of the mutations from DCA-treated animals were at T:A sites.
This is consistent with the previous observation that the proportion of
mutations at T:A sites in codon 61 of the H-ras gene was increased in
DCA-induced liver tumors in B6C3F1 mice. The present study demonstrates
DCA-associated mutagenicity in the mouse liver under conditions in which
DCA produces hepatic tumors.
相似文献
34.
Fatty acid balance studies in term infants fed formula milk containing long-chain polyunsaturated fatty acids 总被引:1,自引:0,他引:1
C Morgan L Davies F Corcoran J Stammers J Colley SA Spencer D Hull 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(2):136-142
Long-chain polyunsaturated fatty acids (LCP) are thought to be required for optimal nervous system development in the newborn. A commercial milk formula containing LCP (Aptamil-LCP) with a fatty acid profile closely resembling breast milk, has recently been introduced for term infants. The absorption of fatty acids in term infants was examined in a double-blind randomized controlled trial comparing Aptamil-LCP ( n = 20) and standard Aptamil ( n = 20). Formula-fed newborn infants were studied from birth for 14 d. Fat balances (3 d) were performed from d 10. A 3-d stool collection was performed from d 10 in a parallel breastfed group ( n = 21). Plasma samples were taken on d 6. Median fat excretion (mg kg−1 ) was 897.1, 615.0 and 355.2 with Aptamil, Aptamil-LCP and breastfeeding, respectively. The median total fat absorption coefficient in Aptamil-LCP-fed infants was higher than in those fed standard Aptamil ( p < 0:01). These findings were accounted for by differences in the excretion and absorption of long-chain saturated fatty acids (C14:0, C16:0 and C18:0). Higher fat excretion was associated with bulkier and firmer stools. Only trace amounts of LCP were detected in the stools of all groups. This accounted for less than 4% of dietary intake in Aptamil-LCP-fed infants. No differences in the utilization of LCP from Aptamil-LCP and breast milk feeding were apparent. Plasma phospholipid fatty acid composition data reflected differences in dietary LCP intake. Thus, PL LCP levels were highest in the breastfed infants and lowest in the Aptamil-fed infants, with values for the Aptamil-LCP-fed group falling in between. 相似文献
35.
Characterization of the insulin-like growth factor axis in a human hepatoma cell line (PLC) 总被引:4,自引:0,他引:4
Scharf JG; Schmidt-Sandte W; Pahernik SA; Ramadori G; Braulke T; Hartmann H 《Carcinogenesis》1998,19(12):2121-2128
36.
Bari? Mülayim Sema Mülayim Nilüfer Yigit Celik 《The European journal of contraception & reproductive health care》2006,11(1):47-49
Perforation of the uterus by an intrauterine device (IUD) is a serious complication occurring at or following 1/350 to 1/2,500 insertions. It is more common among women with 'lost' IUDs. If a woman presents with pelvic pain and a history of a 'lost' IUD, X-rays of the abdomen and of the pelvis should be ordered. We report on a 'lost' IUD that had been inserted 12 years previously. It was found in the lower anterior abdominal wall. Most probably uterine perforation had happened during a dilatation and curettage (D & C) attempted for removal of the device. Thereafter the IUD must have migrated to the abdominal wall. This case illustrates that unless it can be recovered by simple traction on the threads, a trained medical professional should be called upon for removal of the IUD. 相似文献
37.
38.
Renal complications of lipodystrophy: A closer look at the natural history of kidney disease 下载免费PDF全文
Baris Akinci Sadiye Mehtat Unlu Ali Celik Ilgin Yildirim Simsir Sait Sen Banu Nur Fatma Ela Keskin Basak Ozgen Saydam Nilufer Kutbay Ozdemir Banu Sarer Yurekli Bekir Ugur Ergur Melda Sonmez Tahir Atik Atakan Arslan Tevfik Demir Canan Altay Ulku Aybuke Tunc Tugba Arkan Ramazan Gen Erdal Eren Gulcin Akinci Aslihan Arasli Yilmaz Habib Bilen Samim Ozen Aygul Celtik Senay Savas Erdeve Semra Cetinkaya Huseyin Onay Sulen Sarioglu Elif Arioglu Oral 《Clinical endocrinology》2018,89(1):65-75
39.
Mehmet Sabri Gürbüz Ozgur Celik Mehmet Zafer Berkman 《Journal of Korean Neurosurgical Society》2012,52(5):498-500
Cranioplasty is performed using autograft and allograft materials on patients to whom craniectomy was applied previously due to the facts that, this region is open to trauma and the scalp makes irritation and pressure onto the brain paranchyma causing brain atrophy and convulsions. Dramatical improvement of neurological deficits, control of convulsions and partial prevention of cerebral atrophy are achieved after these operations. One of the most important complications of cranioplasty is late infection. Here, we report a 43-year-old male patient admitted with the history of purulant discharge from the right temporal incission site for one year to whom cranioplasty had been performed with allograft material 20 days after craniectomy which had been performed in 1989. Allograft cranioplasty material was removed and cranioplasty was performed using new allograft material with the diagnosis of late cranioplasty infection. 相似文献
40.
Hatice Celik Angela Cremins Keisha A. Jones Oz Harmanli 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2013,17(2):245-248
The advent of robotic surgery has increased the popularity of laparoscopic sacrocolpopexy. Carbon dioxide insufflation, an essential component of laparoscopy, may rarely cause massive subcutaneous emphysema, which may be coincident with life-threatening situations such as hypercarbia, pneumothorax, and pneumomediastinum. Although the literature contains several reports of massive subcutaneous emphysema after a variety of laparoscopic procedures, we were not able to identify any report of this complication associated with laparoscopic or robotic sacrocolpopexy. Massive subcutaneous emphysema occurred in 3 women after robotic sacrocolpopexy in our practice. The patients had remarkable but reversible physical deformities lasting up to 1 week. A valveless endoscopic dynamic pressure system was used in all 3 of our cases. Our objective is to define the risk of massive subcutaneous emphysema during robotic sacrocolpopexy in light of these cases and discuss probable predisposing factors including the use of valveless endoscopic dynamic pressure trocars. 相似文献