全文获取类型
收费全文 | 33237篇 |
免费 | 3963篇 |
国内免费 | 366篇 |
专业分类
耳鼻咽喉 | 797篇 |
儿科学 | 856篇 |
妇产科学 | 603篇 |
基础医学 | 3012篇 |
口腔科学 | 945篇 |
临床医学 | 3234篇 |
内科学 | 8260篇 |
皮肤病学 | 948篇 |
神经病学 | 3201篇 |
特种医学 | 1282篇 |
外科学 | 6649篇 |
综合类 | 174篇 |
现状与发展 | 2篇 |
一般理论 | 1篇 |
预防医学 | 1387篇 |
眼科学 | 702篇 |
药学 | 1759篇 |
中国医学 | 28篇 |
肿瘤学 | 3726篇 |
出版年
2023年 | 634篇 |
2022年 | 393篇 |
2021年 | 702篇 |
2020年 | 956篇 |
2019年 | 506篇 |
2018年 | 1091篇 |
2017年 | 926篇 |
2016年 | 1141篇 |
2015年 | 1117篇 |
2014年 | 1455篇 |
2013年 | 1682篇 |
2012年 | 1279篇 |
2011年 | 1323篇 |
2010年 | 1240篇 |
2009年 | 1356篇 |
2008年 | 1217篇 |
2007年 | 1247篇 |
2006年 | 1275篇 |
2005年 | 1193篇 |
2004年 | 1082篇 |
2003年 | 998篇 |
2002年 | 1034篇 |
2001年 | 1108篇 |
2000年 | 1014篇 |
1999年 | 1019篇 |
1998年 | 546篇 |
1997年 | 498篇 |
1996年 | 585篇 |
1995年 | 443篇 |
1994年 | 333篇 |
1993年 | 272篇 |
1992年 | 658篇 |
1991年 | 618篇 |
1990年 | 575篇 |
1989年 | 582篇 |
1988年 | 529篇 |
1987年 | 508篇 |
1986年 | 461篇 |
1985年 | 478篇 |
1984年 | 365篇 |
1983年 | 259篇 |
1982年 | 186篇 |
1981年 | 148篇 |
1979年 | 243篇 |
1978年 | 187篇 |
1977年 | 183篇 |
1975年 | 153篇 |
1974年 | 150篇 |
1971年 | 154篇 |
1970年 | 148篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Neal M. Blitz DPM FACFAS Jonathan H. Yu BS 《The Journal of foot and ankle surgery》2005,44(3):218-221
Freiberg's infraction is an ostechondrosis of a lesser metatarsal head resulting in degeneration of the metatarsophalangeal joint. Several mechanisms have been suggested in its pathenogenesis. Freiberg first described the entity and believed single impact trauma was the underlying cause. Repetitive biomechanical microtrauma is the most widely accepted etiologic theory. Other factors contributing to its development include aseptic necrosis, ischemia, and a congenital predisposition. We present a case report of Freiberg's infraction occurring in identical twins involving multiple metatarsals in various stages of degeneration. One of the twins was affected unilaterally whereas the other twin was affected bilaterally. Both twins had involvement of the second metatarsal on the same side extremity. The occurrence of Freiberg's infraction in identical twins suggests that an underlying congenital predisposition to the condition may play more of a role than previously considered. 相似文献
32.
P31
The relationship between the relative amount of Porphyromonas gingivalis in saliva and halitosis
Objectives Porphyromonas gingivalis is one of the microorganisms that most actively produce CH3 SH and we have reported that subjects with P . gingivalis have higher CH3 SH levels than subjects without P . gingivalis . However, little is known about the relationship between P . gingivalis levels in saliva and the condition of oral malodor. In this study, we evaluated the association between the relative amount of P . gingivalis in saliva and halitosis in mouth air.
Methods All of the subjects were patients at the Preventive Dentistry and Breath Odor Clinic of Kyushu Dental College, where they received a periodontal examination. Volatile sulfur compounds (VSC: hydrogen sulfide and methyl mercaptan) were measured using gas chromatography. Saliva samples were collected in a sterile plastic tube over a period of 5 min while the subject chewed on paraffin wax, and were then immediately stored at –80°C until use. Template DNA was obtained from the stored saliva using an Easy-DNA Kit (Invitrogen, CA, USA) according to the manufacturer's instructions. Conventional PCR assays were used to confirm the presence of P . gingivalis . A 5' nuclease TaqMan PCR was used to quantify P . gingivalis in saliva. The relative numbers of bacteria were measured using the comparative threshold cycle method.
Results We found a quantitative relationship between the P . gingivalis levels in saliva and the condition of halitosis in mouth air.
Conclusion We analyzed the relationship between the relative amount of P . gingivalis in saliva and oral malodor. 相似文献
Methods All of the subjects were patients at the Preventive Dentistry and Breath Odor Clinic of Kyushu Dental College, where they received a periodontal examination. Volatile sulfur compounds (VSC: hydrogen sulfide and methyl mercaptan) were measured using gas chromatography. Saliva samples were collected in a sterile plastic tube over a period of 5 min while the subject chewed on paraffin wax, and were then immediately stored at –80°C until use. Template DNA was obtained from the stored saliva using an Easy-DNA Kit (Invitrogen, CA, USA) according to the manufacturer's instructions. Conventional PCR assays were used to confirm the presence of P . gingivalis . A 5' nuclease TaqMan PCR was used to quantify P . gingivalis in saliva. The relative numbers of bacteria were measured using the comparative threshold cycle method.
Results We found a quantitative relationship between the P . gingivalis levels in saliva and the condition of halitosis in mouth air.
Conclusion We analyzed the relationship between the relative amount of P . gingivalis in saliva and oral malodor. 相似文献
33.
Philip J. Langlais PhD Mark L. Wardlow BS Hitoshi Yamamoto MD 《Pediatric neurology》1991,7(6):440-445
Cerebrospinal fluid (CSF) from 7 patients with infantile spasms (mean age: 6.7 months) was collected before and after treatment with adrenocorticotropic hormone (ACTH). The concentration of neurotransmitter metabolites was analyzed using high-performance liquid chromatography and compared to the metabolite concentration in the CSF from 7 age-matched controls (mean age: 6.1 months). Pretreatment levels of CSF 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid, 3-methoxy-4-hydroxyphenyl glycol (MHPG), and kynurenine were significantly lower in infantile spasm patients compared to controls. Following treatment, marked increases in 5-HIAA and decreases in kynurenine levels were observed in the CSF of the 5 infants whose seizures were eliminated or reduced by ACTH. In the 2 nonresponders 5-HIAA levels decreased. The level of MHPG was reduced slightly in 5 infants, including the 2 nonresponders, and was increased in 2 responders. CSF homovanillic acid levels increased in 4 infantile spasm infants and decreased in 3 following ACTH. These data demonstrate that the presence of seizures in infantile spasms is associated with a significant decrease in serotonergic activity and that elimination of seizures by ACTH is accompanied by increased serotonin turnover. The simultaneous increase of 5-HIAA and decrease of kynurenine, an alternate metabolite of tryptophan, suggests an underlying disturbance of tryptophan metabolism in infantile spasms. The possibility that elimination of seizures by ACTH may be related to decreased production of certain kynurenine metabolites, particularly quinolinic acid, is discussed. 相似文献
34.
35.
Sho Takahashi Hisato Homma Takehide Akiyama Shinichi Mesawa Kenichiro Hirata Katsuhisa Kogawa Kunihiro Takanashi Hirotoshi Ishiwatari Yutaka Kawano Tsuyoshi Hayashi Kohichi Takada Koji Miyanishi Junji Kato Yoshiro Niitsu 《Nihon Shokakibyo Gakkai zasshi》2007,104(8):1236-1244
A 75-year-old man had been admitted to another hospital because of left abdominal pain, and was given a diagnosis of left hydronephrosis and acute pancreatitis. After a JJ stent insertion and medication, he was transferred to our hospital for further examinations. US and EUS revealed a chronic pancreatitis-like pattern and multicystic lesion in the pancreas head and body. At that time enhanced CT findings showed an extrapancreatic low density area to be inflammatory change, extending from the pancreas body to the left crus of the diaphragm and posteriorly the spreading from the left crus of the diaphragm via the left urinary duct into the left iliopsoas muscle, in which MRI revealed partial high intensity. ERCP and MRCP showed focal irregular narrowing of the pancreatic duct of unknown cause, and we decided that an internal pancreatic fistula due to pancreatitis had induced left ureteral obstruction, caused by a protein plug or alcohol. Follow-up 6 months later showed that extrapancreatic spreading of the low density area had markedly regressed without any change in the ureteral obstruction. 相似文献
36.
Comparison of trichloroethylene and enflurane as adjuncts to nitrous oxide and relaxant anaesthesia 总被引:1,自引:0,他引:1
Forty women who underwent gynaecological surgery were randomly allocated to receive trichloroethylene, enflurane, or enflurane plus fentanyl as adjuncts to nitrous oxide/relaxant anaesthesia with controlled ventilation. No serious cardiac dysrhythmias were seen in any group. Each patient was observed postoperatively for 4 hours by a nurse blind to the technique used, and questioned at 24 hours by a similarly blinded anaesthetist. Recovery after trichloroethylene was not significantly prolonged although postoperative analgesia by visual analogue was better, opiate analgesia was required less frequently and there was less nausea and vomiting than in either of the enflurane groups. We argue for the continued use of trichloroethylene by this technique, because it costs one hundred times less than enflurane and because of the potential morbidity of the postoperative opiate dosage required after enflurane. 相似文献
37.
E.Paul Kirk MB BS J. Santa MD T. Heckler MBA M. Collins MD 《American journal of obstetrics and gynecology》1998,178(6):1222-1228
OBJECTIVE: Our purpose was to assess whether legislative action influenced the role of obstetrician-gynecologists as primary care physicians. STUDY DESIGN: An observational study was performed on the basis of a questionnaire sent to 410 obstetrician-gynecologists and 27 medical directors of managed-care organizations. RESULTS: Of 67% of obstetrician-gynecologists and 96% of medical directors who responded, there was agreement as to the content of primary care, but a minority (38%) of obstetrician-gynecologists identified themselves as primary care providers. A minority of medical directors (35%) felt that obstetrician-gynecologists should serve in that role. Both obstetrician-gynecologists and medical directors felt that legislation had little impact. CONCLUSION: The reticence of obstetrician-gynecologists to assume a major role in primary care appears to be the result of an uneasiness with accepting a more comprehensive role in patient management and gatekeeping. They appear comfortable with the more traditional roles but feel that training and experience has not prepared them well for the management of more complex medical problems. (Am J Obstet Gynecol 1998;178:1222-8.) 相似文献
38.
M Gotoh Y Yoshikawa T Otani T Kato M Kobayashi K Kato M Saito A Kondo K Miyake 《Nihon Hinyōkika Gakkai zasshi. The japanese journal of urology》1990,81(12):1877-1883
Effects of adrenergic alpha-1-blocking agent, prazosin, in the treatment of detrusor external-sphincter dyssynergia (DSD) were evaluated in both experimental and clinical aspects. Experimentally, in the urethral pressure profile in dogs, the maximum urethral closing pressure was depressed after intravenous injection of 1 mg prazosin. When experimental DSD was obtained in dogs by stimulating electrically the unilateral 2nd sacral root, intra-venous injection of 1 mg prazosin inhibited contraction of the external urethral sphincter. Clinically, 74 patients with DSD based on neurogenic bladder from cerebral vascular attack (CVA) (13 cases) and spinal cord injury (61 cases) were retrospectively surveyed in terms of therapeutical effects of prazosin for DSD. Spinal cord injury was subdivided to 4 groups for clinical evaluation; cervical cord injury (C) with complete paralysis, thoracic cord injury (Th) with complete paralysis, lumbar cord injury (L) with complete paralysis and spinal cord injury with incomplete paralysis. Patients with CVA and spinal cord injury with incomplete paralysis showed good response rates in subjective improvement, 69% and 60% respectively. However, those with spinal cord injury with complete paralysis showed a poor response (28% for C, 23% for Th and 14% for L). The amount of residual urine significantly decreased after treatment, in all the groups except that of lumbar cord injury with complete paralysis. In all the groups, however, even after the drug treatment the amount of residual urine ranged from 80 to 170 ml and the rates of needing clean intermittent catheterization unchanged.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
39.
Roberto Civitelli M.D. Eturo Ogata Louis V. Avioli Gary Stein Samuel Edelstein John A. Eisman Yasuho Nishii Hajime Orimo Jane Lian Takuo Fujita Yasufumi Hayashi Shigeaki Kato Tadashi Kobayashi Hirotoshi Morii Rikushi Morita Toshitaka Nakamura Yoshiki Seino Masataka Shiraki Tatsuo Suda Naoyuki Takahashi Hideaki Takahashi Tastuhiko Tanisawa Akifumi Tokita 《Calcified tissue international》1995,57(6):409-414
40.
Binding profile of SM-9018, a novel antipsychotic candidate 总被引:3,自引:0,他引:3
T Kato A Hirose Y Ohno H Shimizu H Tanaka M Nakamura 《Japanese journal of pharmacology》1990,54(4):478-481
The present study employed various receptor-binding assays to clarify the biochemical characteristics of SM-9018. SM-9018 possessed very high affinity for 5-HT2, D2 and 5-HT1A receptors (Ki = 0.61, 1.4 and 2.9 nM, respectively), and it had moderate affinity for alpha 1 and D1 receptors (Ki = 17 and 41 nM, respectively). However, SM-9018 had only negligible affinity for alpha 2, opiate, glutamate, phencyclidine, benzodiazepine and GABAA receptors. These results suggest that SM-9018 may be a novel antipsychotic agent with binding affinity for 5-HT2 and 5-HT1A receptors. 相似文献