全文获取类型
收费全文 | 60893篇 |
免费 | 3622篇 |
国内免费 | 274篇 |
专业分类
耳鼻咽喉 | 825篇 |
儿科学 | 1467篇 |
妇产科学 | 937篇 |
基础医学 | 7200篇 |
口腔科学 | 1286篇 |
临床医学 | 6308篇 |
内科学 | 12791篇 |
皮肤病学 | 1052篇 |
神经病学 | 6123篇 |
特种医学 | 1886篇 |
外科学 | 10161篇 |
综合类 | 641篇 |
一般理论 | 70篇 |
预防医学 | 4464篇 |
眼科学 | 1275篇 |
药学 | 3667篇 |
3篇 | |
中国医学 | 59篇 |
肿瘤学 | 4574篇 |
出版年
2023年 | 295篇 |
2022年 | 492篇 |
2021年 | 1168篇 |
2020年 | 687篇 |
2019年 | 1188篇 |
2018年 | 1419篇 |
2017年 | 1087篇 |
2016年 | 1228篇 |
2015年 | 1373篇 |
2014年 | 1974篇 |
2013年 | 2761篇 |
2012年 | 4358篇 |
2011年 | 4785篇 |
2010年 | 2585篇 |
2009年 | 2411篇 |
2008年 | 4206篇 |
2007年 | 4376篇 |
2006年 | 4309篇 |
2005年 | 4318篇 |
2004年 | 4074篇 |
2003年 | 3875篇 |
2002年 | 3613篇 |
2001年 | 435篇 |
2000年 | 386篇 |
1999年 | 538篇 |
1998年 | 727篇 |
1997年 | 593篇 |
1996年 | 532篇 |
1995年 | 517篇 |
1994年 | 424篇 |
1993年 | 361篇 |
1992年 | 291篇 |
1991年 | 230篇 |
1990年 | 218篇 |
1989年 | 166篇 |
1988年 | 216篇 |
1987年 | 175篇 |
1986年 | 181篇 |
1985年 | 189篇 |
1984年 | 216篇 |
1983年 | 236篇 |
1982年 | 323篇 |
1981年 | 293篇 |
1980年 | 227篇 |
1979年 | 97篇 |
1978年 | 129篇 |
1977年 | 114篇 |
1976年 | 69篇 |
1974年 | 54篇 |
1973年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Steven Perlmutter Christopher T Hsu Patrice A Villa Douglas S Katz 《Journal of ultrasound in medicine》2002,21(9):1047-1051
Jackstone calculi are urinary tract stones that have a specific appearance resembling toy jacks. They are almost always composed of calcium oxalate dihydrate and may be found in the urinary bladder or rarely in the upper urinary tract. Their appearance on plain radiographs and computed tomography (CT) in human patients has been well described. They have also been imaged in several species of animals. However, our review of the English medical literature revealed no previous report in which a jackstone calculus had been identified on the sonographic examination of a human patient. We report a case in which a large jackstone calculus was incidentally detected during abdominal sonography in a 75-year-old man. 相似文献
92.
Prospective assessment of biofeedback for the treatment of paradoxical puborectalis contraction 总被引:25,自引:18,他引:7
Steven D. Wexner M.D. John D. Cheape M.D. Jose M. N. Jorge M.D. Steve Heymen B.A. David G. Jagelman M.D. 《Diseases of the colon and rectum》1992,35(2):145-150
Eighteen patients with chronic constipation were diagnosed as having paradoxical puborectalis contraction (PPC) as the cause for their constipation. The diagnosis of PPC was made after office evaluation, colonic transit study, manometry, cinedefecography, and electromyography (EMG). These 18 patients had a mean duration of symptoms of 26.9 years; none of these patients had unassisted bowel movements. Fourteen patients had a mean of 4.6 laxative-induced bowel evacuations per week, and 11 patients had a mean of 4.4 enema-induced bowel evacuations per week. Patients underwent a mean of 8.9 one-hour EMG-based biofeedback sessions. At a mean follow-up of 9.1 (range, 0.5–12) months, these 18 patients had a mean of 7.3 unassisted bowel actions per week (
P
<0.0001). In addition, persistent laxative use was reported by only two patients, and, in both cases, this was once a week or less (
P
<0.001). Similarly, enema use was reported by only three patients, one once weekly and the other two thrice weekly (
P
<0.002). No biofeedback-related complications were identified. EMG-based biofeedback is a valuable technique associated with an 89 percent success rate in the treatment of PPC.Read at the meeting of The American Society of Colon and Rectal Surgeons, Boston, Massachusetts, May 12 to 17, 1991. 相似文献
93.
Ann E Barr Fayez F Safadi Irene Gorzelany Mamta Amin Steven N Popoff Mary F Barbe 《Journal of bone and mineral research》2003,18(11):2023-2032
Work-related repetitive motion disorders are costly. Immunohistochemical changes in bones resulting from repetitive reaching and grasping in 17 rats were examined. After 3-6 weeks, numbers of ED1+ macrophages and osteoclasts increased at periosteal surfaces of sites of muscle and interosseous membrane attachment and metaphyses of reach and nonreach forelimbs. These findings indicate pathological overloading leading to inflammation and subsequent bone resorption. INTRODUCTION: Sixty-five percent of all occupational illnesses in U.S. private industry are attributed to musculoskeletal disorders arising from the performance of repeated motion, yet the precise mechanisms of tissue pathophysiology have yet to be determined for work-related musculoskeletal disorders. This study investigates changes in upper extremity bone tissues resulting from performance of a voluntary highly repetitive, negligible force reaching and grasping task in rats. MATERIALS AND METHODS: Seventeen rats reached an average of 8.3 times/minute for 45-mg food pellets for 2 h/day, 3 days/week for up to 12 weeks. Seven rats served as normal or trained controls. Radius, ulna, humerus, and scapula were collected bilaterally as follows: radius and ulna at 0, 3, 4, 5, 6, and 12 weeks and humerus and scapula at 0, 4, and 6 weeks. Bones were examined for ED1-immunoreactive mononuclear cells and osteoclasts. Double-labeling immunohistochemistry was performed for ED1 (monocyte/macrophage lineage cell marker) and TRACP (osteoclast marker) to confirm that ED1+ multinucleated cells were osteoclasts. Differences in the number of ED1+ cells over time were analyzed by ANOVA. RESULTS: Between 3 and 6 weeks of task performance, the number of ED1+ mononuclear cells and osteoclasts increased significantly at the periosteal surfaces of the distal radius and ulna of the reach and nonreach limbs compared with control rats. These cells also increased at periosteal surfaces of humerus and scapula of both forelimbs by 4-6 weeks. These cellular increases were greatest at muscle attachments and metaphyseal regions, but they were also present at some interosseous membrane attachments. The number of ED1+ cells decreased to control levels in radius and ulna by 12 weeks. CONCLUSIONS: Increases in ED1+ mononuclear cells and osteoclasts indicate that highly repetitive, negligible force reaching causes pathological overloading of bone leading to inflammation and osteolysis of periosteal bone tissues. 相似文献
94.
Allison K. Dyrlund Steven R. Wininger 《Journal of Applied Biobehavioral Research》2006,11(3-4):133-146
The purpose of this study was to evaluate the barrier efficacy and cognitive evaluation theory with regard to predicting exercise attendance. Participants consisted of 189 undergraduates attending not-for-credit fitness classes at a regional comprehensive university in the Midwest. A revised 17-item version of the Intrinsic Motivation Inventory was used to assess exercise enjoyment and the three components of self-determination theory (competence, autonomy, and relatedness). A modified version of the Self-Efficacy Scale was used to assess self-efficacy. Attendance was significantly correlated with competency and self-efficacy. Regression results revealed that class, relatedness, and competence accounted for a significant amount of variance in attendance. Future research should examine the effects of competence-enhancing strategies on exercise adherence. 相似文献
95.
Tetrabenazine (TBZ), a presynaptic dopamine depletor and postsynaptic dopamine receptor blocker, is widely used for the treatment of hyperkinetic movement disorders in adults. However, reports of its use in children are limited. We review the efficacy and tolerability of TBZ therapy in 31 children with hyperkinetic movement disorders refractory to other medications. TBZ was effective in reducing the severity of movement disorders resistant to treatment with other medicines. When compared to adult patients, pediatric patients required higher doses. Side effects were similar to the adult population; however, children had a lower incidence of drug-induced Parkinsonism. 相似文献
96.
Peter M Miller Ruth Stockdell Lynne Nemeth Chris Feifer Ruth G Jenkins Paul J Nietert Andrea Wessell Heather Liszka Steven Ornstein 《Substance Abuse》2006,27(1-2):61-70
Many medical conditions are caused or exacerbated by heavy drinking, necessitating alcohol screening and discussion in primary care practices. This is particularly true of hypertension, the most common primary diagnosis in the United States, which has been linked to the regular consumption of 3 or more standard alcoholic beverages a day. The Accelerating Alcohol Screening-Translating Research into Practice (AA-TRIP) project was designed to improve detection and management of alcohol problems in primary care patients with hypertension. Medical providers are being trained using the Practice Partner Research Network's- Translating Research into Practice (PPRNet-TRIP) quality improvement model. This includes a multi-method intervention (electronic medical records, on-site academic detailing, practice feedback reports and annual network meetings) to help practices increase adherence to clinical guidelines. Qualitative analyses of initial steps taken by nine primary care practices toward the routine implementation of alcohol screening guidelines are presented. Organizational factors and provider and patient characteristics all influenced the method and consistency of alcohol screening and intervention. Perceived time constraints, patient sensitivity to questions about alcohol, and possible stigma associated with a diagnosis of alcoholism were also relevant barriers requiring problem solving. 相似文献
97.
Mesenteric cyst is one of the rarest abdominal tumours, with approximately 820 cases reported since 1507. The incidence varies from 1 per 100000 to 250000 admissions. The lack of characteristic clinical features and radiological signs may present great diagnostic difficulties. The cyst may present in one of three ways: (i) non-specific abdominal features; (ii) an incidental finding; or (iii) an acute abdomen. Abdominal pain is the major presenting symptom. Abdominal mass is found in more than 50% of cases and 40% of cases are discovered incidentally. More than one aetiological mechanism is probably involved in the development of mesenteric cysts. Mesenteric cysts have been reported from the duodenum to the rectal mesentery but are most commonly located in the ileal mesentery. Malignant cysts occur in less than 3% of cases. Enucleation of the cyst is the treatment of choice. Knowledge of these tumours is important due to the various complications associated with suboptimal surgical management. Two cases of mesenteric cysts are presented including a recurrent mesenteric cyst in a post-partum woman demonstrating the inferior technique of internal marsupialization. The association of mesenteric cyst with pregnancy is discussed. 相似文献
98.
Steven V. Johnson Pharm.D. Lori L. Hoey Pharm.D. Kyle Vance-Bryan Pharm.D. 《Pharmacotherapy》1995,15(5):579-585
Increasing reports of vancomycin resistance have raised concerns about the future effectiveness of this drug in treatment of critically ill patients with gram-positive infections. Due to these concerns the Centers for Disease Control and Prevention (CDC) recently published criteria that delineate the prudent use of vancomycin. Using these criteria, we attempted to determine the appropriateness of vancomycin prescribing patterns at our institution. A retrospective chart review was performed for 135 hospitalized patients treated between May 1993 and April 1994. Inappropriate empiric vancomycin use was documented in 81 (60%) of these patients. When culture results were available, 28 (21%) patients inappropriately received the drug. Results of this study are similar to those of other studies of vancomycin use in hospitals based on non-CDC criteria. If CDC criteria are to have a positive impact on physicians' vancomycin prescribing patterns, significant educational efforts will be required. 相似文献
99.
100.
Nitrous oxide does not exacerbate pulmonary hypertension or ventricular dysfunction in patients with mitral valvular disease 总被引:1,自引:0,他引:1
Using the rapid-response thermistor pulmonary artery catheter and transoesophageal echocardiography, this study examined the effects of 100 per cent oxygen, 70 per cent nitrous oxide/30 per cent oxygen, and 70 per cent nitrogen/30 per cent oxygen on the pulmonary circulation and ventricular function in ten patients with pulmonary hypertension. In comparison with baseline measurements, nitrous oxide administration resulted in small but statistically significant (P less than 0.05) changes in mean arterial pressure (76 +/- 14 to 67 +/- 12), mean pulmonary arterial pressure (37 +/- 14 to 33 +/- 13 mmHg), and cardiac output (3.7 +/- 1.4 to 3.2 +/- 1.1 L.min-1). Seventy per cent nitrogen resulted in no significant changes from baseline. The repeat 100 per cent oxygen measurements were nearly identical to the nitrous oxide measurements. It is concluded that nitrous oxide does not exacerbate pulmonary hypertension or ventricular dysfunction during high-dose fentanyl anaesthesia in patients with mitral valvular disease. 相似文献