全文获取类型
收费全文 | 2770158篇 |
免费 | 200986篇 |
国内免费 | 8110篇 |
专业分类
耳鼻咽喉 | 36299篇 |
儿科学 | 90122篇 |
妇产科学 | 75113篇 |
基础医学 | 386671篇 |
口腔科学 | 73424篇 |
临床医学 | 254159篇 |
内科学 | 553565篇 |
皮肤病学 | 65036篇 |
神经病学 | 232758篇 |
特种医学 | 107989篇 |
外国民族医学 | 749篇 |
外科学 | 414955篇 |
综合类 | 52512篇 |
现状与发展 | 6篇 |
一般理论 | 1137篇 |
预防医学 | 209820篇 |
眼科学 | 61302篇 |
药学 | 200766篇 |
9篇 | |
中国医学 | 5598篇 |
肿瘤学 | 157264篇 |
出版年
2021年 | 23948篇 |
2019年 | 24389篇 |
2018年 | 33917篇 |
2017年 | 25997篇 |
2016年 | 29879篇 |
2015年 | 33783篇 |
2014年 | 46784篇 |
2013年 | 69319篇 |
2012年 | 93486篇 |
2011年 | 98414篇 |
2010年 | 58937篇 |
2009年 | 56495篇 |
2008年 | 91634篇 |
2007年 | 97058篇 |
2006年 | 98435篇 |
2005年 | 94636篇 |
2004年 | 90908篇 |
2003年 | 87162篇 |
2002年 | 84004篇 |
2001年 | 130083篇 |
2000年 | 132545篇 |
1999年 | 112188篇 |
1998年 | 33466篇 |
1997年 | 29664篇 |
1996年 | 29770篇 |
1995年 | 28805篇 |
1994年 | 26297篇 |
1993年 | 24608篇 |
1992年 | 86063篇 |
1991年 | 82400篇 |
1990年 | 79502篇 |
1989年 | 76742篇 |
1988年 | 70056篇 |
1987年 | 68550篇 |
1986年 | 64115篇 |
1985年 | 61125篇 |
1984年 | 45730篇 |
1983年 | 38635篇 |
1982年 | 23323篇 |
1981年 | 20810篇 |
1979年 | 39405篇 |
1978年 | 27900篇 |
1977年 | 23652篇 |
1976年 | 21875篇 |
1975年 | 23109篇 |
1974年 | 27099篇 |
1973年 | 25639篇 |
1972年 | 23944篇 |
1971年 | 22135篇 |
1970年 | 20289篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
K. HELLMAN M. LUNDELL† C. SILFVERSWÄRD‡ B. NILSSON§ A.-C. HELLSTRÖM & B. FRANKENDAL 《International journal of gynecological cancer》2006,16(3):1201-1211
The goal of this retrospective study concerning primary carcinoma of the vagina (PCV) was to analyze clinical and histopathologic prognostic factors in one of the largest known material, which comprised 314 patients. PCV is a rare disease, and the majority of published studies are based on small materials; therefore, the established knowledge concerning prognostic factors is insufficient. Routine treatment is based on irradiation with risk for undertreatment or overtreatment, which leads to unnecessary complications in the absence of prognostic factors. The overall 5-year disease-specific survival rate in this study was 45% and in stage I 75%. In the univariate statistical analysis, several factors correlated significantly with disease-specific survival. However, in the multivariate analysis, there were only three factors that independently could predict poor survival-high age at diagnosis, large tumors (> or =4 cm), and advanced stage. Common background factors with no prognostic significance were prior hysterectomy, other gynecological malignancies, and pelvic irradiation. In conclusion, this study has elucidated three strong prognostic factors that might be considered in the choice of therapy and also for modification of the FIGO guidelines. Increased knowledge concerning complementary biologic markers to discriminate between low- and high malignant tumors is however of great importance. 相似文献
992.
Frederieke M Brouwers Graeme Eisenhofer Jacques W M Lenders Karel Pacak 《Endocrinology & Metabolism Clinics of North America》2006,35(4):699-724, viii
Pheochromocytoma may lead to important emergency situations, ranging from cardiovascular emergencies to acute abdomen and multiorgan failure. It is vital to think about this disease in any emergency situation when conventional therapy fails to achieve control or symptoms occur that do not fit the initial diagnosis. The importance of keeping this diagnosis in minds is underscored by the fact that, in 50% of pheochromocytoma patients, the diagnosis is initially overlooked. Two other tumors of the sympathetic nervous system, neuroblastoma and ganglioneuroma, are less commonly associated with emergency conditions. If they occur, they are often linked to catecholamine excess, paraneoplastic phenomena, or local tumor mass effect. 相似文献
993.
Dr. D. Süsskind S. Aisenbrey J. M. Rohrbach 《Der Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft》2006,103(5):421-424
Ohne Zusammenfassung 相似文献
994.
995.
Michael D Levitt Julie K Furne Michael Kuskowski John Ruddy 《Clinical gastroenterology and hepatology》2006,4(2):123-129
BACKGROUND & AIMS: Breath methane measurements reflect the in situ activity of the methanogenic colonic flora. Thirty-five years ago we found that 34% of healthy adult subjects were methane producers (breath methane level >1 ppm above atmospheric methane levels). The current study presents a new survey of breath methane levels designed to determine if the activity of the methanogenic flora has changed over the past 35 years. In addition, we review insights into the methanogenic flora that have resulted from breath methane measurements. METHODS: The end-alveolar breath methane concentrations of 212 healthy adults living in the Minneapolis area were determined via gas chromatography. The influence of sex, age, and bowel movement frequency on methane production was assessed. RESULTS: The findings that 36.4% of participants were methane producers, with a mean methane concentration in these producers of 16.6 ppm, are strikingly similar to the values of 33.6% and 15.2 ppm observed 35 years ago. Neither sex nor age showed a statistically significant relationship to methane production. There was a negative correlation between frequency of bowel movements and breath methane concentration in methane producers. CONCLUSIONS: The activity of the methanogenic flora of healthy adults remained remarkably stable over the past 35 years despite widespread antibiotic use and dietary changes. A literature review revealed that many associations have been shown between methane production and clinical states, but it remains to be determined if methanogens actively influence human physiology or are simply a marker of colonic function. 相似文献
996.
997.
Gonadotropins mediate DNA synthesis and protection from spontaneous cell death in human ovarian surface epithelium 总被引:2,自引:0,他引:2
R.J. EDMONDSON J.M. MONAGHAN & B.R. DAVIES† 《International journal of gynecological cancer》2006,16(1):171-177
Gonadotropins have been implicated in the development of epithelial ovarian cancers. These tumors are derived from ovarian surface epithelium (OSE). The purpose of this study was to determine the effects of these hormones on DNA synthesis and spontaneous cell death in primary cultures of OSE and three immortalized OSE cultures. Primary cultures of OSE cells were generated from the ovaries of women with benign disease. The effects of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on DNA synthesis and cell death were determined using [(3)H]thymidine incorporation and JAM assays. Significant inductions of DNA synthesis were demonstrated with LH in 4/12 (33%) primary cultures of OSE and 2/3 OSE cell lines and with FSH in 4/11 (36%) primary cultures of OSE and 2/3 OSE cell lines. A significant protection from cell death was also observed in the presence of FSH in 2/4 primary cultures of OSE and 1/3 OSE cell lines and in the presence of LH in 1/4 primary cultures of OSE and 2/3 OSE cell lines. The results indicate that while gonadotropins have the potential to induce cell proliferation and protect from cell death in OSE cells in vitro, their effects are variable in OSE cells from different women. 相似文献
998.
999.
C G Arruda J M Aldrighi L A Bortolotto I N Alecrin J A F Ramires 《Gynecological endocrinology》2006,22(10):557-563
BACKGROUND: Arterial hypertension and postmenopausal reduction of estrogen levels may be involved in modifications of the stiffness of large arteries. OBJECTIVES: To evaluate the pulse-wave velocity (PWV) and indirectly the arterial stiffness in hypertensive postmenopausal women submitted to hormone therapy with estradiol alone or combined with norethisterone acetate. SUBJECTS: Forty-five hypertensive postmenopausal women were double-blindly, randomly assigned to three arms of treatment: placebo (group I); estradiol 2 mg/day (group II); or estradiol 2 mg/day and norethisterone acetate 1 mg/day (group III). METHODS: Arterial stiffness was assessed from PWV measurements of the common carotid and femoral arteries (CF-PWV) and the common carotid and radial arteries (CR-PWV) obtained using the automatic Complior(R) device, taken at baseline and after 12 weeks of treatment. RESULTS: After the 12-week treatment, values of CF-PWV and CR-PWV were not significantly different (p = 0.910 and p = 0.736, respectively) among the groups. Systolic blood pressure showed a positive correlation with CF-PWV in groups II and III (p = 0.02 and p < 0.001, respectively). CONCLUSIONS: PWV and arterial stiffness in postmenopausal hypertensive women did not reduce over a 12-week treatment with estradiol alone compared with the same period of treatment with estradiol combined with norethisterone acetate. 相似文献
1000.
Female urinary incontinence is a common but underreported condition. Initial investigation and treatment can in most cases be undertaken without urodynamic or other detailed tests. History by the use of validated symptom and quality of life questionnaires is key to the initial investigation. Initial treatment includes pelvic floor muscle training (PFMT) regardless of the type of incontinence; lifestyle interventions and bladder retraining, anticholinergics and serotonin/noradrenaline reuptake inhibitors (e.g. duloxetine) are also included depending on the type of symptoms. In mixed incontinence the predominant symptom should be treated first. When this initial treatment is ineffective, further investigation should be offered prior to specialised treatment. Urodynamics should be considered for all patients prior to surgery. Imaging and cystoscopy to exclude pathology, for example in elderly patients with an overactive bladder, are also necessary. Newer surgical interventions should be offered after careful consideration of the risk:benefit ratio for each individual woman and the amount of evidence that is currently available to support their use. 相似文献