首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3679篇
  免费   162篇
  国内免费   15篇
耳鼻咽喉   127篇
儿科学   254篇
妇产科学   272篇
基础医学   307篇
口腔科学   84篇
临床医学   295篇
内科学   698篇
皮肤病学   57篇
神经病学   244篇
特种医学   113篇
外科学   850篇
综合类   61篇
一般理论   1篇
预防医学   90篇
眼科学   96篇
药学   199篇
中国医学   8篇
肿瘤学   100篇
  2023年   22篇
  2022年   43篇
  2021年   53篇
  2020年   39篇
  2019年   55篇
  2018年   97篇
  2017年   64篇
  2016年   103篇
  2015年   100篇
  2014年   114篇
  2013年   201篇
  2012年   237篇
  2011年   256篇
  2010年   154篇
  2009年   138篇
  2008年   270篇
  2007年   296篇
  2006年   267篇
  2005年   287篇
  2004年   275篇
  2003年   231篇
  2002年   199篇
  2001年   82篇
  2000年   57篇
  1999年   53篇
  1998年   20篇
  1997年   11篇
  1996年   15篇
  1995年   14篇
  1994年   9篇
  1993年   3篇
  1992年   14篇
  1991年   8篇
  1990年   9篇
  1989年   11篇
  1988年   10篇
  1987年   8篇
  1986年   4篇
  1985年   8篇
  1984年   2篇
  1980年   1篇
  1979年   2篇
  1978年   2篇
  1976年   3篇
  1975年   1篇
  1972年   1篇
  1970年   1篇
  1968年   2篇
  1967年   1篇
  1966年   1篇
排序方式: 共有3856条查询结果,搜索用时 12 毫秒
41.
Introduction: Testicular sperm extraction (TESE) is well-defined procedure for surgical sperm retrieval in obstructive and non-obstructive azoospermia. This study was focused on the effectiveness of testicular sperm extraction and intracytoplasmic sperm injection (ICSI) for azoospermic men with different female age subgroups.Materials and methods: A total of 107 men with azoospermia underwent TESE and ICSI treatment. The women were examined in three groups 20–29, 30–34 and 35 years or older. The main outcome in this study was fertilization and pregnancy rates with TESE and ICSI.Results: Spermatozoa were successfully retrieved during 97 of 107 (90.7%) TESE attempts, resulting in the fertilization of 286 of 563 (50.4%) injected metaphase II oocytes. Two hundred and fifty-five of them were transferred (89.8%). The clinical pregnancy rate and ongoing pregnancy rate per embryo transfer were 22.5% and 20.6% respectively. When comparing the fertilization and pregnancy rates, it was observed that women between the ages of 20–29 years had significantly higher pregnancy rates than women over 34 years of age (p < 0.05).Conclusion: The female age is a major factor in determining successful implantation in ICSI.  相似文献   
42.
The clinic usage of cisplatin, an anticancer drug, is limited due to it has many side effects in many systems and organs. In this context, it was aimed to investigate the protective effect of hesperidin, a citrus flavonoid, on testicular and spermatological damages induced by cisplatin in rats. The rats were randomly divided into four groups. The first group was kept as a control. In the second groups, cisplatin was given at the single dose of 7 mg kg?1 intraperitoneally. In the third group, hesperidin was orally administered at the dose of 50 mg/kg day?1 for 14 days. In the fourth group, cisplatin and hesperidin were given together at the same doses. Cisplatin treatment caused significant reductions enzymatic (SOD, CAT and GPx) and nonenzymatic (GSH) antioxidants and significant induction level of TBARS. In addition, cisplatin treatment caused decreased sperm motility, epididymal sperm concentration, increased abnormal sperm rate and histopathological damage. In contrast, hesperidin treatment significantly attenuated the harmful effects. In conclusion, this study clearly demonstrated that hesperidin has protective effects on cisplatin‐induced reproductive system toxicity depending on its antioxidant properties. Thus, it is thought that hesperidin may be useful against cisplatin toxicity in patients with cancer in terms of reproductive system.  相似文献   
43.
Patients with erectile dysfunction, who admitted to 4 different urological centres in Turkey were evaluated in terms of aetiological factors to establish the aetiology of erectile dysfunction in our population and compare it with the data derived from Western communities. After the history, physical examination, psychological evaluation and laboratory testing, a clinical diagnosis was established as primarily psychogenic, organic, or mixed aetiology. Mean patient age was 43.5 years (range 17 to 69), and 9 of the patients were unmarried. Of the patients 53 had vascular risk factors, and 10 reported a history of alcohol abuse. Eleven patients were using drugs that might interfere with the disorder. In this multicentral study of 115 impotent men, an organic cause was found in 43%, psychogenic in 47%, and mixed in 19%. Mean age of the overall patients was 43.48. When the ages of the patients with organic erectile dysfunction and those with psychogenic erectile dysfunction were compared, it was clearly seen that those with organic erectile dysfunction were much older (52.73 versus 33.02). This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
44.
Peyronie's disease is most commonly seen in the fifth decade of life. However, a wide range of age (20-83 y) is reported. During a 6-year period, men with Peyronie's disease presenting under the age of 40 were reviewed retrospectively and followed-up. The prevalence of Peyronie's patients presenting under age 40 was 8.2%. Their mean age was 32.47 +/- 5.37 (range: 23-39) y and 78.9% of them presented during the acute phase of the disease. Pain on erection was a part of presenting symptom complex in 52.6% and the majority (84%) had a degree of penile curvature < 60 degrees. Erectile dysfunction (ED) was present in 21% of patients, who responded well to intracavernous injection test. After a minimal 2-year follow-up, improvement in penile deformity was observed in 36.8%, and 42.1% had stable disease while 21% experienced deterioration of the penile curvature. The onset of Peyronie's disease is clinically more noisy and acute in patients presenting under age 40 and this forces the physicians to treat them more vigorously.  相似文献   
45.
Solitary fibrous tumors of the pleura are neoplasms of the mesenchymal tissue of the pleural mesothelium. The most frequent symptoms are dyspnea, coughing and chest pain. A 45-year-old female patient presented after a thoracic contusion. A radio-opaque image was evidenced on chest X-ray. At the initial hospital, a hemorrhagic fluid was aspirated at thoracocentesis and the patient was transferred to our hospital with diagnosis of traumatic hemothorax. A thoracic CT showed a tumoral formation filling two-thirds of the left hemithorax. The transthoracic biopsy finding was compatible with a fibrous tumor. The patient was taken for surgery and the large pleural tumor was excised. In conclusion, a large pleural fibrous tumor was initially mistaken for hemothorax. A CT-scan revealed the tumoral nature of the thoracic opacity.  相似文献   
46.
Background: Hypotension due to vasodilatation after spinal anesthesia (SA) may be harmful. Heart rate variability, an indirect measure of autonomic control, may predict hypotension.

Methods: One hundred patients were studied. Retrospectively, heart rate variability was analyzed in 30 patients, classified depending on the lowest systolic blood pressure (SBP) after SA. Seventy patients were studied prospectively, assigned to one of two groups by their low to high frequency ratio (LF/HF) before SA. Sensitivity and specificity of LF/HF for prediction of decrease of SBP greater 20% of baseline were tested.

Results: Retrospective analysis showed differences of LF/HF depending on the degree of hypotension after SA. Prospective analysis demonstrated significant differences of SBP after SA depending on baseline LF/HF (mean +/- SD): low LF/HF (1.3 +/- 0.7) = > SBP: 91 +/- 8% of baseline versus high LF/HF (5.5 +/- 2.4) = > SBP: 66 +/- 10% of baseline (P < 0.05). Baseline LF/HF as well as high frequency and proportional decrease of SBP after SA correlated significantly, in contrast to baseline hemodynamic parameters heart rate and SBP. A receiver operator curve characteristic analysis showed a sensitivity and specificity of LF/HF > 2.5 of 85% to predict SBP decrease of greater than 20% of baseline after SA.  相似文献   

47.
Pulmonary artery aneurysm (PAA) is a rare entity with fatal complications. Its silent course contributes to large aneurysms with compression symptoms. We present a 39-year-old female idiopathic pulmonary arterial hypertension patient with a giant PAA causing severe pulmonary regurgitation (PR) and symptomatic left main coronary artery compression (LMCA). Since she had a failed LMCA stenting attempt, she underwent surgery. A valve-sparing David-like pulmonary trunk reconstruction and coronary artery bypass were performed. This case illustrates that David-like reconstruction procedure can be applied to the PAA with severe PR.  相似文献   
48.
BACKGROUND: Pseudoexfoliation (PEX), which affects anterior segment structures, is thought to be a systemic disorder. The purpose of this study was to determine the possible relation between PEX and sensorineural hearing loss. METHODS: The study group included 51 patients with PEX and 22 controls without PEX. The patients and controls underwent complete ophthalmic and otorhinolaryngologic examinations. Hearing levels were evaluated with audio-tympanogram battery in all cases, and pure-tone audiogram hearing levels were classified into 6 groups. RESULTS: The mean age of PEX subjects was 67.5 years. All patients had PEX in at least one eye. Seventeen eyes had no evidence of PEX syndrome or glaucoma, 14 eyes had PEX but no glaucoma, and 71 eyes had both PEX and glaucoma. Thirty-four patients had bilateral PEX while 17 patients had unilateral PEX. One hundred and two ears of the 51 PEX patients and 44 ears of 22 controls were evaluated with pure-tone audiogram after otologic examination. In PEX patients 34/102 ears (33.3%) had normal hearing level, and 68 (66.7%) had hearing loss at various levels. The mean age of the control group was 61 years. In this group, 27/44 ears (61.4%) had no hearing loss, and 17 (38.6%) ears had hearing loss. There was a statistically significant difference between control and PEX subjects (p<0.01) in terms of hearing loss. INTERPRETATION: This study shows that sensorineural hearing loss appears to be associated with PEX.  相似文献   
49.
BACKGROUND: Several groups have shown the involvement of oxidative stress in the pathophysiology of vitiligo. METHODS: In this study, we examined the erythrocyte and plasma activities of glutathione peroxidase and Cu/Zn superoxide dismutase, plasma nitrite/nitrate levels, and erythrocyte catalase activity in 23 vitiligo patients and 25 controls. RESULTS: The results show that erythrocyte superoxide dismutase activity and plasma nitrite/nitrate levels are high in vitiligo patients. CONCLUSIONS: Our study confirms that oxidative stress is involved in the pathophysiology of vitiligo, as indicated by the high levels of erythrocyte superoxide dismutase activity and plasma nitrite/nitrate.  相似文献   
50.
ObjectiveThe aim of this study was to determine the epidemiologic characteristics of, and the treatments used for, recurrent herpes labialis (RHL) in health students.MethodsA cross-sectional study was conducted with the participation of 333 nursing and midwifery students. Data on the sociodemographic characteristics of the participants, their history of RHL, and the treatments were collected by means of a standard self-reported questionnaire form.ResultsThe point prevalence of RHL was 3.9%, the annual prevalence was 44.7%, and the lifetime prevalence was 52.5%. These prevalences were not related to the participants' place of residence, level of income, school, gender, marital status, or smoking status (p > 0.05). RHL was frequently seen on the right side of the lower lip (17.9%). One third of the students who experienced RHL stated that they had applied treatment to the lesion. However, only 20.1% stated that they had used antiviral therapy. Treatment was recommended by a physician for only 16.1% of the subjects.ConclusionsThe prevalence of RHL was high among the health students, who were considered to represent young adults. Although they were students in a school of health, they lacked knowledge about RHL.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号