全文获取类型
收费全文 | 22595篇 |
免费 | 1024篇 |
国内免费 | 168篇 |
专业分类
耳鼻咽喉 | 257篇 |
儿科学 | 392篇 |
妇产科学 | 330篇 |
基础医学 | 3324篇 |
口腔科学 | 360篇 |
临床医学 | 1983篇 |
内科学 | 4188篇 |
皮肤病学 | 720篇 |
神经病学 | 2793篇 |
特种医学 | 1406篇 |
外科学 | 2808篇 |
综合类 | 155篇 |
一般理论 | 6篇 |
预防医学 | 952篇 |
眼科学 | 506篇 |
药学 | 1881篇 |
中国医学 | 29篇 |
肿瘤学 | 1697篇 |
出版年
2023年 | 94篇 |
2022年 | 153篇 |
2021年 | 277篇 |
2020年 | 235篇 |
2019年 | 281篇 |
2018年 | 381篇 |
2017年 | 296篇 |
2016年 | 442篇 |
2015年 | 485篇 |
2014年 | 674篇 |
2013年 | 835篇 |
2012年 | 1317篇 |
2011年 | 1396篇 |
2010年 | 800篇 |
2009年 | 815篇 |
2008年 | 1461篇 |
2007年 | 1494篇 |
2006年 | 1589篇 |
2005年 | 1620篇 |
2004年 | 1478篇 |
2003年 | 1520篇 |
2002年 | 1426篇 |
2001年 | 282篇 |
2000年 | 248篇 |
1999年 | 309篇 |
1998年 | 336篇 |
1997年 | 278篇 |
1996年 | 219篇 |
1995年 | 177篇 |
1994年 | 205篇 |
1993年 | 155篇 |
1992年 | 115篇 |
1991年 | 133篇 |
1990年 | 127篇 |
1989年 | 113篇 |
1988年 | 111篇 |
1987年 | 73篇 |
1986年 | 76篇 |
1985年 | 82篇 |
1984年 | 94篇 |
1983年 | 82篇 |
1982年 | 86篇 |
1981年 | 99篇 |
1980年 | 73篇 |
1979年 | 65篇 |
1978年 | 49篇 |
1977年 | 65篇 |
1976年 | 67篇 |
1974年 | 59篇 |
1955年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
Dr. med. Wolfgang Ludewig 《International archives of occupational and environmental health》1941,11(2):296-310
Ohne ZusammenfassungDie einzelnen Befunde wurden auf Schwert-Karte DIN A 5 Nr. 24 988 festgelegt.Am Schlusse der Arbeit crlaube ich mir, dem Herrn Reichsarbeitsminister für die Bereitstellung der erforderlichen Mittel ergebenst zu danken. 相似文献
64.
Johannes M. Mayr Wolfgang Grechenig Michael E. Höllwarth 《European Journal of Trauma》2004,30(3):150-160
Abstract
Background and Purpose:
The radiologic evaluation of musculoskeletal injuries in young children is difficult due to the absent ossification of several secondary ossification centers, which therefore cannot be seen directly on plain radiographs. When relying on conventional radiographs, even severe cartilaginous or soft tissue injuries cannot be visualized, as there is no possibility to differentiate them from bruises or sprains. It is the aim of this review to present clinically relevant applications of ultrasound imaging in pediatric musculoskeletal trauma.
Methods:
Currently used ultrasound techniques for evaluation of typical pediatric fractures or joint dislocations, techniques for differentiation between stable and unstable intraarticular fractures, the use of sonography for monitoring reduced bone length in long bones after fracture, sonographic guidelines for evaluation of tendon injuries or lesions, and sonographic imaging techniques in arthritis and osteomyelitis are described.
Conclusion:
Musculoskeletal sonography—despite its inability to view through intact cortical bone and its accuracy being dependent on skill and experience of the investigator—provides important information about soft tissue, bony or cartilaginous injuries in children. 相似文献
65.
Ingmar Königsrainer Wolfgang Steurer Maria Witte Alfred Königsrainer 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2007,392(4):485-488
Background Nowadays, liver resection is a routine operative procedure in surgical centers, and strategies must be aimed at avoiding additional
risk factors. Extrahepatic isolation of portal vein, hepatic artery and hepatic duct, as well as lymphadenectomy of the liver
hilum are generally accepted steps of liver resection, even for metastatic and benign indications. Our primary aim was to
analyze the feasibility, blood loss, blood transfusion requirements, incidence of complications, and outcome using the approach
for intrahepatic devascularization leaving the extrahepatic hilus untouched.
Materials and methods Thirty-eight consecutive patients with resection for metastases and benign liver tumors were selected. After hilar examination,
the extrahepatic structures remain intact, and during parenchyma dissection, the whole right or left or the appropriate bi-segmental
pedicle is isolated intrahepatically and then transected using a stapler device.
Results The used technique was feasible in all cases, and no intra- or postoperative surgical complications were observed. To date,
no tumor recurrence was found in the hilum during the follow-up period.
Conclusion The intrahepatic pedicle stapling technique appears to be feasible and safe in liver resection. Hilar dissection can, thus,
be avoided in liver metastasis and benign liver tumors. 相似文献
66.
OBJECTIVES: We have previously shown that the levels of circulatory fetal DNA are elevated in preeclampsia and that these increases correspond to disease severity. Several reports have indicated that increased levels of antiphospholipid (anti-PL) and anti-DNA antibodies may be associated with preeclampsia, in particular with the severe forms of the disorder. Since the release of cell-free DNA by the placenta is attributed to some form of cell death or damage and as anti-PL and anti-double-stranded DNA (dsDNA) antibodies have been proposed to lead to placental damage, we have studied the relationship between these parameters in preeclampsia. METHODS: Circulating fetal DNA levels in samples taken from pregnant women with mild (n = 12) or severe (n = 12) preeclampsia and from normal pregnant controls (n = 35) were quantified using a Taqman real-time Polymerase Chain Reaction (PCR) assay. The Anti-PL antibodies (IgG and IgM) were assayed by anticardiolipin ELISA and by commercial anti-beta2-Glycoprotein I (GPI) ELISA kits. Anti-dsDNA antibodies (IgG and IgM) were analyzed by a commercially available anti-dsDNA ELISA kit. RESULTS: No correlation could be drawn with the quantity of circulatory fetal DNA in the samples analyzed and corresponding anti-PL or anti-dsDNA antibody levels. Furthermore, no significant difference existed between the levels of these antibodies in the two study groups and the control cohort. CONCLUSION: Our data suggest that the mechanism leading to the increased release of cell-free circulatory DNA from the placenta does not involve trophoblast damage mediated by these agents. Our analysis also questions the reported involvement of anti-PL and anti-DNA antibodies in preeclampsia. 相似文献
67.
Naoyuki Hashiguchi Yu Chen Christian Rusu David B. Hoyt Wolfgang G Junger 《European Journal of Trauma》2005,31(4):379-388
AbstractBackground and Purpose: Polymorphonuclear neutrophils (PMNs) protect the host from invading microorganisms, but excessive PMN activation after trauma causes tissue injury. Rapid monitoring of PMN function is critical for the assessment of the inflammatory state of trauma patients. Here, the authors adapted two simple and rapid methods to measure oxidative burst and degranulation of human PMNs in whole blood to avoid potential interference of cell isolation procedures with the assessment of PMN function.Material and Methods: Heparinized blood was drawn from healthy volunteers or trauma patients, preincubated at 37 °C for 5 min, and stimulated with N-formyl-methionyl-leucyl-phenylalanine (fMLP). Four assays for oxidative burst were tested: (1) cytochrome C; (2) homovanillic acid (HVA); (3) Amplex® Red; and (4) flow cytometry with dihydrorhodamine 123 (DHR). PMN degranulation was assessed with flow cytometry using antibodies to: (1) CD11b/Mac-1 (CD18); (2) CD63; and (3) CD66b (CD67).Results: With the exception of the DHR method, all methods to measure oxidative burst were found to be unsuitable in whole blood due to interference of plasma proteins and hemoglobin with the fluorimetric or photometric readouts. By contrast, all degranulation methods were suitable for whole-blood studies. However, for the assessment of formyl peptide-induced degranulation, anti-antibodies to CD11b/Mac-1 and CD66b were up to five times more sensitive than antibodies to CD63. Thus, the degranulation and DHR methods were optimized for increased sensitivity, speed, and specificity and their usefulness to measure PMN function in trauma patients was tested.Conclusion: The whole-blood methods based on flow cytometry with DHR, anti-CD11b/Mac-1, and anti- CD66b are rapid, simple, and reliable techniques to assess PMN function for trauma research. 相似文献
68.
Lia Assumpcao John L. Cameron Christopher L. Wolfgang Barish Edil Michael A. Choti Joseph M. Herman Jean-Francois Geschwind Kelvin Hong Christos Georgiades Richard D. Schulick Timothy M. Pawlik 《Journal of gastrointestinal surgery》2008,12(11):1915-1923
Background
No data on incidence, management, or natural history of chyle leaks following pancreatic resection have been published. We
sought to identify possible risk factors associated with chyle leaks following pancreatic resection, as well as determine
the natural history of this rare complication.
Methods
Between 1993 and 2008, 3,532 patients underwent pancreatic resection at a single institution. Data on demographics, operative
details, primary tumor status, and chyle leak were collected. To identify risk factors associated with chyle leak, a matched
3:1 paired analysis was performed.
Results
Of 3,532 patients undergoing pancreatic resection, 47 (1.3%) developed a chyle leak (n = 34, contained chyle leak versus n = 13, diffuse chylous ascites). Chyle leak was identified at median 5 days following surgery. Median drain triglyceride levels
were 592 ng/dl. After matching on tumor size, disease etiology, and resection type, the number of lymph nodes harvested and
history of concomitant vascular resection predicted higher risk of chyle leak (both P < 0.05). Total parenteral nutrition (TPN) was required in more patients with chylous ascites (92.3%) than those with chyle
leaks (44.1%) (P = 0.003). The median time to resolution was shorter for contained chyle leaks (13 days) versus chylous ascites (36 days)
(P < 0.001). Patients with chylous ascites tended to have shorter overall survival (3-year, 18.8%) versus patients with no chyle
leak (3-year, 46.9%) (P = 0.12). In contrast, patients with a contained chyle leak had a similar survival as patients with no chyle leak (3-year,
53.4% versus 46.9%, respectively) (P = 0.32).
Conclusion
Chyle leak was a rare (1.3%) complication following pancreatic resection that was associated with number of lymph nodes harvested
and concomitant vascular resection. In general, chyle leaks were successfully managed with TPN with no adverse impact on outcome.
Patients with chylous ascites, however, had a more protracted clinical course and tended to have a worse long-term survival.
Presented at the Society for Surgery of the Alimentary Tract, 49th Annual Meeting, San Diego, CA, May 18th, 2008
Support: Dr. Pawlik is supported by Grant Number 1KL2RR025006-01 from the National Center for Research Resources (NCRR), a
component of the National Institutes of Health (NIH), and NIH Roadmap for Medical Research. The contents of this publication
are solely the responsibility of the authors and do not necessarily represent the official view of NCRR or NIH. 相似文献
69.
Dirk Mayer Wolfgang Dreher Dieter Leibfritz Daniel M Spielman 《Magnetic resonance in medicine》2007,57(5):967-971
A numerical simulation tool was developed to calculate the echo amplitudes of J-coupled resonances within a series of radiofrequency (RF) refocused echoes. The signal modulation due to J-coupling in rapid acquisition with relaxation enhancement (RARE) is suppressed only when the inverse of the pulse interval (tau) is large compared to both the chemical shift (CS) difference (Deltadelta) of the coupled spins and the coupling constant. In contrast, the echo amplitudes in ultrafast low-flip-angle RARE (U-FLARE) oscillate around a quasi-steady-state value that is greater than zero (neglecting relaxation and diffusion) even when Deltadelta > 1/tau. The flip-angle distribution over the measured slice caused by the use of Gaussian-shape slice-selective refocusing pulses further reduces the echo oscillations. When the pulse interval falls short of the fast pulse rate regime, spectroscopic U-FLARE provides an improved spatial impulse response in the phase-encoding (PE) direction compared to spectroscopic RARE. 相似文献
70.