全文获取类型
收费全文 | 167469篇 |
免费 | 44013篇 |
国内免费 | 226篇 |
专业分类
耳鼻咽喉 | 2615篇 |
儿科学 | 6205篇 |
妇产科学 | 2506篇 |
基础医学 | 27436篇 |
口腔科学 | 8785篇 |
临床医学 | 19085篇 |
内科学 | 44483篇 |
皮肤病学 | 9318篇 |
神经病学 | 20880篇 |
特种医学 | 4271篇 |
外科学 | 25483篇 |
综合类 | 464篇 |
现状与发展 | 1篇 |
一般理论 | 60篇 |
预防医学 | 12365篇 |
眼科学 | 2845篇 |
药学 | 11635篇 |
中国医学 | 1365篇 |
肿瘤学 | 11906篇 |
出版年
2023年 | 591篇 |
2022年 | 563篇 |
2021年 | 2843篇 |
2020年 | 5999篇 |
2019年 | 12423篇 |
2018年 | 12486篇 |
2017年 | 12828篇 |
2016年 | 13560篇 |
2015年 | 14041篇 |
2014年 | 14113篇 |
2013年 | 15674篇 |
2012年 | 11681篇 |
2011年 | 11903篇 |
2010年 | 12340篇 |
2009年 | 7824篇 |
2008年 | 8585篇 |
2007年 | 7748篇 |
2006年 | 7697篇 |
2005年 | 7153篇 |
2004年 | 6572篇 |
2003年 | 6066篇 |
2002年 | 5852篇 |
2001年 | 2743篇 |
2000年 | 3209篇 |
1999年 | 1639篇 |
1998年 | 398篇 |
1997年 | 282篇 |
1996年 | 263篇 |
1995年 | 271篇 |
1994年 | 229篇 |
1993年 | 201篇 |
1992年 | 319篇 |
1991年 | 313篇 |
1990年 | 240篇 |
1989年 | 243篇 |
1988年 | 178篇 |
1987年 | 160篇 |
1986年 | 173篇 |
1985年 | 194篇 |
1984年 | 185篇 |
1983年 | 125篇 |
1982年 | 135篇 |
1981年 | 118篇 |
1980年 | 133篇 |
1979年 | 119篇 |
1978年 | 117篇 |
1977年 | 77篇 |
1975年 | 87篇 |
1974年 | 116篇 |
1973年 | 88篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
Awadé AC Efstathiou T 《Journal of chromatography. B, Biomedical sciences and applications》1999,723(1-2):69-74
This paper describes and compares three chromatographic methods for the analysis of egg-white proteins. Gel-permeation chromatography allowed the separation of seven peaks from egg white, with an almost total protein recovery. A clean separation of ovomucin and lysozyme from the bulk of the proteins was obtained with this method. Reversed-phase high-performance liquid chromatography led to the fractionation of at least eight peaks. With this chromatographic method, the recovery was relatively poor. Approximately 30% of the ovalbumin was retained in the column after the elution. Finally, eleven chromatographic peaks were separated from egg white by high-performance liquid chromatography on an anion-exchange column. The recovery of proteins was almost total. The latter method afforded higher resolution. 相似文献
982.
Quiralte J Sánchez-García F Torres MJ Blanco C Castillo R Ortega N de Castro FR Pérez-Aciego P Carrillo T 《The Journal of allergy and clinical immunology》1999,103(4):685-689
BACKGROUND: Several HLA alleles have been associated with asthma induced by nonsteroidal anti-inflammatory drugs (NSAIDs). The existence of HLA markers linked to other NSAID-induced reactions, such as cutaneous and anaphylactoid reactions, has not been established. OBJECTIVE: The purpose of our work was to study the HLA-DRB1 and HLA-DQB1 alleles in patients with cutaneous and anaphylactoid reactions caused by NSAIDs. METHODS: We have analyzed 114 HLA DRB1 and 26 HLA-DQB1 alleles in 21 patients with anaphylactoid reactions caused by NSAIDs, 47 patients who had exclusively cutaneous reactions during single-blind, placebo-controlled oral challenges with NSAIDs, and 167 tolerant control subjects (29 of whom had also had an IgE-mediated anaphylaxis to different agents). HLA-DRB1 and HLA-DQB1 alleles were typed by the polymerase chain reaction sequence-specific primers method with genomic DNA. RESULTS: The frequency of HLA-DR11 alleles was 58.8% in the anaphylactoid reaction group, compared with 15.9% in the NSAID-tolerant healthy control subjects (OR, 7:3; 95% confidence interval, 2.8-19.0; P <.02) and 6.3% in the group of the patients with a tolerance for NSAIDs and with IgE-mediated anaphylaxis (OR, 18.75; 95% confidence interval, 4.3-81.1; P <.004). No differences were observed among HLA-DR11 alleles analyzed. There were no significant HLA-DQB1 associations with NSAID-induced anaphylactoid reactions. Patients with cutaneous reactions had HLA frequencies that did not differ significantly from the tolerant control subjects. CONCLUSION: The HLA-DRB1*11 alleles showed a positive association with NSAID-induced anaphylactoid reactions. 相似文献
983.
Mailed, home-obtained urine specimens: a reliable screening approach for detecting asymptomatic Chlamydia trachomatis infections 总被引:7,自引:0,他引:7 下载免费PDF全文
Morré SA van Valkengoed IG de Jong A Boeke AJ van Eijk JT Meijer CJ van den Brule AJ 《Journal of clinical microbiology》1999,37(4):976-980
The use of mailed, home-obtained urine specimens could facilitate screening programs for the detection of asymptomatic Chlamydia trachomatis infections. Since transport time could have an adverse effect on the sensitivity of C. trachomatis detection by PCR, the influence of DNA degradation on amplification was monitored over the course of 1 week. Therefore, urine specimens were aliquoted on the day of collection or arrival. Two groups of urine specimens were investigated. Group I contains first-void C. trachomatis-positive and -negative urine samples. DNA degradation was monitored in group I samples for 7 days at room temperature (RT) and at 4 degrees C by amplifying different lengths of the human beta-globin gene and the C. trachomatis plasmid target. DNA degradation was observed only for the larger human beta-globin fragments at days 5 to 7 at RT. In contrast, at 4 degrees C all targets could be amplified. Urine specimens were also frozen and thawed before aliquoting to mimic freezing during transport. This resulted in a lower sensitivity for the detection of C. trachomatis after thawing and 3 to 4 days at RT. In addition, mailed, home-obtained C. trachomatis-positive urine specimens (group II) were analyzed for 7 days after arrival by two commercially available C. trachomatis detection systems (PCR and ligase chain reaction [LCR]). The C. trachomatis plasmid target in mailed, home-obtained urine specimens could be amplified by both PCR and LCR after 1 week of storage and/or transport at RT. In conclusion, our findings indicate that mailed, home-obtained urine specimens are suitable for the sensitive detection of asymptomatic C. trachomatis infections by amplification methods, even if the transport time is up to 1 week at RT. These findings support the feasibility and validity of screening programs based on mailed, home-obtained urine specimens. Larger studies should be initiated to confirm our results. 相似文献
984.
OBJECTIVE: To perform a retrospective analysis of patients with nasopalatine duct cysts (NPDC) in Brazil and compare with previous analyses. MATERIALS AND METHODS: The files of the Laboratory of Oral Pathology (Minas Gerais Federal University) from 1966 to 1997 were reviewed. Demographic, clinical and histologic data of patients with nasopalatine duct cysts were collected. RESULTS: The mean age of patients with nasopalatine duct cysts at the time of diagnosis was 37.4 years and with a predilection for males. The majority of cases were asymptomatic. Histologically, non-keratinized stratified squamous epithelium alone or in combination with other epithelia was observed in 93% of the cases. Recurrence was not recorded. CONCLUSION: The demographic, histopathological, radiographic, and clinical data of the NPDC in our series are similar to previous studies in other populations. 相似文献
985.
Mignon F Mesurolle B Sissakian JF Bruckert F Guichoux F Barré O Chagnon S Lacombe P 《Journal de radiologie》1999,80(9):939-942
We report a case of metachronous metastasis from renal cell carcinoma to the contralateral adrenal gland detected one year after radical nephrectomy. The initial tumor was incidentally discovered in the setting of acute aortic dissection. A large left adrenal tumor was detected on CT follow-up at two years. Retrospectively, a hypervascular lesion was present on the first yearly CT examination. Adrenalectomy was performed. There is no evidence of recurrent disease at 12 months. The patient was also treated with oral steroids. Because of their location and of the particularities of available therapeutic options, and because these metastases can occur late, long-term sonographic and CT follow-up should be performed. The clinical, imaging, therapeutic and prognostic aspects of these lesions will be discussed. 相似文献
986.
987.
Lacombe P Qanadli SD Coggia M Mignon F Barré O Sissakian JF Bruckert F Chagnon S Dubourg O 《Journal de radiologie》1999,80(1):53-55
We report a thoracic outlet syndrome revealed by neurological complications. Angiography of the subclavian artery depicted an isolated positional occlusion of the descending scapular artery. This side branch of the subclavian artery is anatomically located close to and supplies the brachial plexus. Surgical treatment led to improvement of most symptoms and post-operative control angiography was normal. Not previously described, this sign illustrates the objective compression of the brachial plexus. Ischemia is perhaps intricated with compression, a well-known pathophysiological mechanism of neurological complications in this syndrome. This artery feeding the brachial plexus is usually ligated during surgical neurolysis but must be preserved in order to improve recovery of neurological function and prevent surgical failures. 相似文献
988.
Gouzi JL Bloom E Julio C Labbé F Sans N el Rassi Z Carrère N Pradère B 《Chirurgie; mémoires de l'Académie de chirurgie》1999,124(1):31-37
AIM OF THE STUDY: To describe a technique of percutaneous CT guided catheter drainage of infected pancreatic necrosis and to report the results of this technique compared with those of the conventional surgical treatment and of other percutaneous drainage series. PATIENTS AND METHODS: Between 1992 and 1997, the series included 32 patients who had a severe acute necrotizing pancreatitis with a mean Ranson score of 4.6, scored into grade D (n = 10), and grade E (n = 22), according to the Balthazar radiological staging. Modified Van Sonnenberg 24 F double lumen catheters were used for continuous irrigation and aspiration. RESULTS: Forty-nine drains were inserted for 41 infected necroses and eight abscesses. Among the 32 patients, the proof of infected necrosis was obtained in 26 patients by fine needle aspiration and culture (enterococcus, staphylococcus, pseudomonas). The average delay of catheter insertion was 23 days after onset of pancreatitis; the mean duration of drainage was 43 days, and an average of three catheters per patient was required. Five patients (15%) died, and among the survivors, 16 (59%) presented 21 complications including 14 enterocutaneous or pancreatic fistulas. A subsequent surgical procedure including two necrosectomies was necessary in six patients. CONCLUSION: This study demonstrates that percutaneous drainage of infected pancreatic necrosis with a 15% mortality and 70% success rate, represents an interesting alternative to conventional surgery. 相似文献
989.
A retrospective study was done of all patients with a suspicious mammographic breast lesion surgically biopsied in our institution within the last 5 years. Incidence of invasive versus non-invasive carcinoma and stage at presentation (according to TNM classification system) of palpable and non-palpable lesions were compared. We found a significant difference of non-invasive carcinoma in non-palpable and palpable cancers: 42.2% versus 4.3% (p < 0.001). Patients with a non-palpable invasive carcinoma presenting at stage I (i.e. pT1 with no axillary metastasis) rated significantly higher compared to those with palpable lesions 51.8% versus 9.4% (p < 0.001). The true positive biopsy rate is 30%. As low as 10% has been considered reasonable. We have a total of 56% carcinomas detected on all biopsies: 30% for non-palpable lesions and 66.8% for palpable lesions. A more aggressive approach towards screening and biopsy of breast lesions might increase early detection of carcinoma and so improve survival. 相似文献
990.