全文获取类型
收费全文 | 2787篇 |
免费 | 278篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 36篇 |
儿科学 | 120篇 |
妇产科学 | 131篇 |
基础医学 | 461篇 |
口腔科学 | 75篇 |
临床医学 | 338篇 |
内科学 | 645篇 |
皮肤病学 | 55篇 |
神经病学 | 89篇 |
特种医学 | 289篇 |
外科学 | 227篇 |
综合类 | 64篇 |
预防医学 | 148篇 |
眼科学 | 36篇 |
药学 | 158篇 |
1篇 | |
中国医学 | 3篇 |
肿瘤学 | 213篇 |
出版年
2024年 | 4篇 |
2023年 | 7篇 |
2022年 | 17篇 |
2021年 | 37篇 |
2020年 | 29篇 |
2019年 | 51篇 |
2018年 | 59篇 |
2017年 | 31篇 |
2016年 | 49篇 |
2015年 | 68篇 |
2014年 | 73篇 |
2013年 | 117篇 |
2012年 | 132篇 |
2011年 | 157篇 |
2010年 | 153篇 |
2009年 | 132篇 |
2008年 | 109篇 |
2007年 | 130篇 |
2006年 | 117篇 |
2005年 | 136篇 |
2004年 | 112篇 |
2003年 | 98篇 |
2002年 | 103篇 |
2001年 | 83篇 |
2000年 | 72篇 |
1999年 | 78篇 |
1998年 | 95篇 |
1997年 | 93篇 |
1996年 | 66篇 |
1995年 | 66篇 |
1994年 | 44篇 |
1993年 | 49篇 |
1992年 | 36篇 |
1991年 | 43篇 |
1990年 | 39篇 |
1989年 | 61篇 |
1988年 | 49篇 |
1987年 | 44篇 |
1986年 | 39篇 |
1985年 | 35篇 |
1984年 | 22篇 |
1983年 | 20篇 |
1982年 | 19篇 |
1981年 | 23篇 |
1980年 | 20篇 |
1979年 | 12篇 |
1978年 | 20篇 |
1977年 | 12篇 |
1976年 | 13篇 |
1975年 | 8篇 |
排序方式: 共有3089条查询结果,搜索用时 15 毫秒
31.
Stephens RW; Golder JP; Fayle DR; Hume DA; Hapel AJ; Allan W; Fordham CJ; Doe WF 《Blood》1985,66(2):333-337
Adherent monolayer cultures of human blood monocytes, peritoneal macrophages, bone marrow macrophages, and colonic mucosa macrophages were examined for their ability to produce and secrete minactivin, a specific inactivator of urokinase-type plasminogen activator. All except colonic mucosa macrophages produced and secreted appreciable amounts of minactivin, but only blood monocytes were stimulated by muramyl dipeptide (adjuvant peptide) to increase production. The minactivin from each of these populations could be shown to preferentially inhibit urokinase-type plasminogen activator and not trypsin, plasmin, or "tissue"-type plasminogen activator (HPA66). A plasminogen-activating enzyme present in monocyte cultures appeared unaffected by the presence of minactivin and could be shown to be regulated independently by dexamethasone. 相似文献
32.
Since LH receptors are decreased in atretic follicles known to contain high androgen levels, we have studied the androgen modulation of LH receptor formation in vitro. Granulosa cells from hypophysectomized, diethylstilbestrol-treated rats were cultured for 3 days with FSH in the presence or absence of nonaromatizable androgens, dihydrotestosterone and 5 alpha-androstane-3 alpha, 17 beta-diol, or a synthetic androgen, R1881 (17 beta-hydroxy-17 alpha-methyl-4,9,11-estratrien-3-one). FSH increased LH receptor content in granulosa cells, while concomitant androgen treatment decreased LH receptor content in a dose- and time-dependent manner, without changing the equilibrium dissociation constant (Kd) for human CG. R1881 (10(-7) M), dihydrotestosterone (10(-6) M), and 5 alpha-androstane-3 alpha, 17 beta-diol (10(-6) M) inhibited LH receptor content by 68%, 65%, and 65%, respectively. Similar to earlier findings, these androgens enhanced FSH-stimulated progesterone biosynthesis and aromatase activity in the same cells. To study their LH responsiveness, androgen-treated cells were washed and reincubated for 2 more days with or without LH. Although basal progesterone production was elevated by R1881 pretreatment, the androgen-pretreated cells were less responsive to LH. Treatment with cyanoketone, an inhibitor of 3 beta-hydroxysteroid dehydrogenase, did not alter the inhibitory effects of R1881 on LH receptors, indicating that the androgen action is not mediated by endogenous progestins. Furthermore, R1881 inhibited the stimulation of LH receptor formation by forskolin, cholera toxin, and 8-bromo-cAMP, suggesting that androgens may inhibit LH receptor induction by affecting post-cAMP events. Estrogen treatment enhanced the FSH induction of LH receptor content, while concomitant addition of R1881 also suppressed the estrogen action. Thus, androgens inhibit FSH-induced functional LH receptors in cultured rat granulosa cells. The androgen effect is exerted, at least partially, at post-cAMP sites and is independent of changes in progestin biosynthesis. 相似文献
33.
Bochicchio GV Baquero F Hsueh PR Paterson DL Rossi F Snyder TA McCarroll K Satishchandran V Dinubile MJ Chow JW 《Surgical infections》2006,7(6):537-545
BACKGROUND: Since 2002, the worldwide Study for Monitoring Antimicrobial Resistance Trends (SMART) has tracked resistance patterns among aerobic and facultative gram-negative bacilli isolated from patients with intra-abdominal infections. Escherichia coli has been by far the most frequently isolated species. METHODS: Antimicrobial susceptibilities for consecutive non-duplicate isolates of aerobic and facultative gram-negative bacilli recovered from intra-abdominal infections were determined by standard broth microdilution techniques. A subanalysis was performed for E. coli isolates from the first three years of the study. RESULTS: A total of 7,002 E. coli isolates were recovered, most commonly from the peritoneal cavity followed by the biliary tract. Susceptibility rates to the 12 antimicrobial agents tested differed among geographic regions, with isolates from Asia/Pacific generally having the highest resistance rates. Overall, extended-spectrum beta-lactamase (ESBL)-producers had a more antibiotic-resistant profile than non-ESBL-producers but usually were susceptible to the carbapenems and amikacin. Community-acquired E. coli strains comprised slightly more than one-half of the isolates and were susceptible to the agents tested more frequently than were hospital-acquired E. coli. CONCLUSIONS: The prevalence of antimicrobial resistance among E. coli isolated from intraabdominal infections is not inconsequential, especially in the Asia/Pacific region. The carbapenems and amikacin were consistently active in vitro against E. coli isolates worldwide, including ESBL-producers. 相似文献
34.
Oesophageal rupture is a life-threatening complication of balloon tamponade for bleeding oesophageal varices. We herein describe the clinical course and imaging findings in a 33-year-old Indian man who had a Sengstaken-Blakemore (SB) tube inserted for uncontrolled haematemesis, which was unfortunately complicated by malposition of the gastric balloon with resultant oesophageal rupture. The inflated SB tube gastric balloon was visualised within the right hemithorax on chest radiography after the SB tube insertion. Further evaluation of the thorax on computed tomography confirmed the diagnosis of oesophageal rupture associated with right-sided haemopneumothorax. It is crucial for both the referring clinician and reporting radiologist to recognise early the imaging features of an incorrectly positioned SB tube gastric balloon, so as to ensure prompt intervention and a reduction in patient morbidity and mortality. 相似文献
35.
36.
Saskia PJ Verkleij Pim AJ Luijsterburg Sten P Willemsen Bart W Koes Arthur M Bohnen Sita MA Bierma-Zeinstra 《The British journal of general practice》2015,65(637):e530-e537
Background
The effectiveness of diclofenac versus paracetamol in primary care patients with pain caused by knee osteoarthritis is unclear.Aim
To assess the effectiveness of diclofenac compared with paracetamol over a period of 2, 4, and 12 weeks in patients with knee osteoarthritis.Design and setting
Randomised controlled trial in general practice.Method
There were 104 patients included in the study, they were aged ≥45 years consulting their GP with knee pain caused by knee osteoarthritis. Patients were randomly allocated to diclofenac (n = 52) or paracetamol (n = 52) for at least 2 weeks. Primary outcomes were daily knee pain severity, and knee pain and function measured with the Knee Injury and Osteoarthritis Outcome Score (KOOS).Results
Over a period of 2- and 4-weeks follow-up, no significant difference in daily knee pain was found between the patient groups: estimated differences of 0.5 (95% CI = −0.2 to 1.3) and −0.2 (95% CI = −1.0 to 0.7), respectively. Over the 12-weeks follow-up, no significant differences were found between both groups for KOOS pain: estimated difference of −2.8 (95% CI = −10.7 to 5.1) and KOOS function of −2.7 (−10.6 to 5.0).Conclusion
Over a period of 2- and 4-weeks follow-up no significant difference in daily measured knee pain severity was found between primary care patients with knee osteoarthritis taking paracetamol or diclofenac. Also, over a period of 12-weeks follow-up no significant differences were found regarding KOOS pain and KOOS function between both groups. Patients more frequently reported minor adverse events after taking diclofenac (64%) than paracetamol (46%). 相似文献37.
Stage-dependent role of growth differentiation factor-9 in ovarian follicle development 总被引:4,自引:0,他引:4
GDF-9 was shown to be essential for follicle progression and is the only factor secreted by the oocyte shown to increase the number of primordial and primary follicles in vivo. Furthermore, GDF-9 is a major growth factor involved in the oocyte control of granulosa cell differentiation. A concentration gradient of the paracrine factor GDF-9 established by the oocyte could provide the basis to explain the stratification of granulosa cells in antral and preovulatory follicles. The stimulatory effects of GDF-9 on early follicle development provide a basis for the use of GDF-9 in the treatment of infertility. 相似文献
38.
39.
STUDY OBJECTIVES: To investigate the clinical, epidemiologic, and microbiological characteristics of community-acquired pneumonia (CAP) due to Acinetobacter baumannii. METHODS: Retrospective chart and radiographic reviews of all patients who were admitted to National Taiwan University Hospital from January 1993 to August 1999, fulfilled the criteria for CAP, and had an isolate of A. baumannii from blood or pleural fluid at hospital admission. RESULTS: Thirteen patients (9 men and 4 women; age range, 37 to 85 years) met the criteria. Conditions associated with the infection included male gender, old age, alcoholism, malignancy, cerebrovascular disease, diabetes mellitus, renal disease, and liver cirrhosis. Eleven patients (85%) acquired the infection during the warmer months of April to October. Twelve patients (92%) had a fulminant course presenting with septic shock and respiratory failure, and 11 patients (85%) needed ventilator support and were treated in an ICU. Six patients (46%) had leukopenia. Lobar consolidations were found in 12 patients (92%), and pleural effusions were present in 4 patients (31%). All patients had positive blood culture results, two patients (15%) had positive pleural effusion culture findings, and nine patients (69%) positive sputum culture results. All the isolates were susceptible to imipenem, and most were susceptible to aminoglycosides, ceftazidime, ciprofloxacin, and extended-spectrum penicillins. Eight patients (62%) died. Four of the five survivors were initially treated with combination of a third-generation cephalosporin and an aminoglycoside. CONCLUSION: A. baumannii should be considered as a possible etiologic agent in community-acquired lobar pneumonia when (1) patients with a fulminant course present during the warmer and more humid months of the year, and (2) patients are younger alcoholics. A good sputum smear, defined as a Gram stain smear of an adequate sputum specimen that comes from the lower respiratory tract and contains > 25 leukocytes per high-power (100x) field on microscopic examination, can help early diagnosis and treatment. A combination of a third-generation cephalosporin and an aminoglycoside may be appropriate empirical therapy. 相似文献
40.
Hollenberg NK Anzalone DA Falkner B Fisher ND Hopkins PN Hsueh W Hutchinson H Krauss RM Price DA Raskin P Reaven GM 《American journal of hypertension》2001,14(3):218-223
BACKGROUND: Although it is widely recognized that there are familial elements in the pathogenesis of hypertension, remarkably little is known about the influence of family history on response to specific antihypertensive agents. METHODS: This study was designed to address that issue by comparing the depressor response to lisinopril in a dose range of 10 to 40 mg in 74 patients enrolled as sibling pairs. Because all patients were treated with lisinopril, ambulatory blood pressure monitoring (ABPM), an objective measure not influenced by the investigators, was used to assess the primary blood pressure (BP) outcome variable. RESULTS: Diastolic BP was highly correlated between sibling pairs at baseline (r = 0.476; P < .03) and on treatment (r = 0.524; P = .0021). Ethnicity/race had a striking influence on lisinopril dose and response rate. Among African American patients, 23 of 28 reached the top dose of 40 mg/day, whereas only 14 of 36 Caucasian patients reached that dose level. Among Caucasians, 92% responded, and only 48% of African Americans. Responders were characterized by being younger and heavier, having significantly lower microalbuminuria at baseline, higher baseline renal plasma flow (RPF), and higher urinary kallikrein. CONCLUSION: Among Caucasians, the presence of a hypertensive sibling predicts a striking therapeutic response to angiotensin converting enzyme inhibition. 相似文献