全文获取类型
收费全文 | 41404篇 |
免费 | 3628篇 |
国内免费 | 160篇 |
专业分类
耳鼻咽喉 | 629篇 |
儿科学 | 1065篇 |
妇产科学 | 801篇 |
基础医学 | 5330篇 |
口腔科学 | 1001篇 |
临床医学 | 4051篇 |
内科学 | 9258篇 |
皮肤病学 | 400篇 |
神经病学 | 3481篇 |
特种医学 | 1362篇 |
外科学 | 6964篇 |
综合类 | 865篇 |
一般理论 | 31篇 |
预防医学 | 3428篇 |
眼科学 | 986篇 |
药学 | 2648篇 |
中国医学 | 83篇 |
肿瘤学 | 2809篇 |
出版年
2022年 | 235篇 |
2021年 | 690篇 |
2020年 | 397篇 |
2019年 | 690篇 |
2018年 | 791篇 |
2017年 | 665篇 |
2016年 | 655篇 |
2015年 | 732篇 |
2014年 | 1164篇 |
2013年 | 1700篇 |
2012年 | 2511篇 |
2011年 | 2580篇 |
2010年 | 1406篇 |
2009年 | 1327篇 |
2008年 | 2361篇 |
2007年 | 2504篇 |
2006年 | 2641篇 |
2005年 | 2623篇 |
2004年 | 2419篇 |
2003年 | 2495篇 |
2002年 | 2322篇 |
2001年 | 649篇 |
2000年 | 702篇 |
1999年 | 689篇 |
1998年 | 606篇 |
1997年 | 480篇 |
1996年 | 452篇 |
1995年 | 385篇 |
1994年 | 362篇 |
1993年 | 318篇 |
1992年 | 497篇 |
1991年 | 469篇 |
1990年 | 414篇 |
1989年 | 413篇 |
1988年 | 390篇 |
1987年 | 381篇 |
1986年 | 347篇 |
1985年 | 355篇 |
1984年 | 340篇 |
1983年 | 276篇 |
1982年 | 277篇 |
1981年 | 279篇 |
1980年 | 225篇 |
1979年 | 246篇 |
1978年 | 240篇 |
1977年 | 186篇 |
1976年 | 171篇 |
1974年 | 167篇 |
1973年 | 182篇 |
1972年 | 162篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
52.
Hand-assisted laparoscopic nephroureterectomy for upper urinary tract transitional cell carcinoma. 总被引:1,自引:0,他引:1
Jay D Raman Michael A Palese Casey K Ng Stephen A Boorjian Douglas S Scherr Joseph J Del Pizzo R Ernest Sosa 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2006,10(4):432-438
OBJECTIVE: We report our experience with hand-assisted laparoscopic nephroureterectomy (HALN) for upper urinary tract transitional cell carcinoma and compare our results with a contemporary series of open nephroureterectomy (ON) performed at our institution. METHODS: Between August 1996 and May 2003, 90 patients underwent nephroureterectomy for upper-tract transitional cell carcinoma (TCC). Thirty-eight patients underwent HALN, while 52 had an ON. End-points of comparison included operative time, estimated blood loss (EBL), intraoperative and postoperative complications, length of hospital stay, pathologic grade and stage of tumor, and tumor recurrence. RESULTS: The mean patient age was 72.3 and 70.6 years in the ON and HALN groups, respectively. Mean operative duration was 243 minutes (ON) and 244 minutes (HALN), with an EBL of 478mL in the open group versus 191 mL in the hand-assisted group (P<0.001). No intraoperative complications occurred, but postoperative complications occurred in 4% and 11% of the ON and HALN groups, respectively (P=0.21). The mean hospital duration was 7.1 days (ON) versus 4.6 days (HALN) (P<0.01). No difference existed in the pathologic grade or stage distribution of urothelial tumors between the 2 groups. The mean follow-up was 51.0 months in the ON group and 31.7 months in the HALN group. Recurrence of urothelial carcinoma occurred in 50% of patients who underwent ON and 40% treated by HALN (P=0.38) at a median interval of 9.1 and 7.7 months, respectively, after surgery. CONCLUSION: Hand-assisted laparoscopic nephroureterectomy is an effective modality for the treatment of upper urinary tract urothelial carcinoma. Patients benefited from less intraoperative blood loss and a shorter hospitalization with an equivalent intermediate-term oncologic outcome compared with that of the open approach. 相似文献
53.
54.
55.
J. Lee Jenkins MD MSc Robert E. O'Connor MD MPH David C. Cone MD 《Academic emergency medicine》2006,13(11):1169-1172
This breakout session at the Academic Emergency Medicine 2006 Consensus Conference examined how baseline overcrowding impedes the ability of emergency departments to respond to sudden, unexpected surges in demand for patient care. Differences between daily and catastrophic surge were discussed, and the need to invoke a hospital-wide response to surge was explored. 相似文献
56.
Luis Hernandez-Garcia Gregory R Lee Alberto L Vazquez Chun-Yu Yip Douglas C Noll 《Magnetic resonance in medicine》2005,54(4):955-964
A new approach to modeling the signal observed in arterial spin labeling (ASL) experiments during changing perfusion conditions is presented in this article. The new model uses numerical methods to extend first-order kinetic principles to include the changes in arrival time of the arterial tag that occur during neuronal activation. Estimation of the perfusion function from the ASL signal using this model is also demonstrated. The estimation algorithm uses a roughness penalty as well as prior information. The approach is demonstrated in numerical simulations and human experiments. The approach presented here is particularly suitable for fast ASL acquisition schemes, such as turbo continuous ASL (Turbo-CASL), which allows subtraction pairs to be acquired in less than 3 s but is sensitive to arrival time changes. This modeling approach can also be extended to other acquisition schemes. 相似文献
57.
58.
59.
To study the possible role of arginine vasopressin (AVP) in the control of haemostasis AVP infusions at 3 doses (0.1, 0.2 and 0.3 mU/kg/min) were performed in 6 male volunteers. Both plasma and platelet AVP concentrations rose in a dose-related manner. At doses of 0.2 and 0.3 mU/kg/min there was an increase in the plasma concentrations of both plasma Factor VIII and von Willebrand factor. The data support the hypothesis that AVP, by interacting with platelets and stimulating factor VIII and von Willebrand factor release, plays a role in the control of haemostasis. 相似文献
60.
Elsa Murray Ph.D. Estralita Martin Douglas Burton Leonard J. Deftos 《Journal of bone and mineral research》1989,4(6):831-838
Biochemical and molecular biological studies of osteoblastic cell function and hormonal regulation are frequently confounded by the inherent cellular heterogeneity and phenotypic instability of existing in vitro and in vivo model systems. A new technique (derived from Western blotting or antibody-based detection of protein molecules bound to nitrocellulose paper) is described for identification of individual cells which synthesize osteoblast-specific gene products (bone Gla-protein, type I collagen, and alkaline phosphatase) or produce cAMP in response to parathyroid hormone (PTH) or isoproterenol. Dispersed primary neonatal rat calvariae or osteogenic sarcoma cells were “plated” on Immobilon-P (a hydrophobic transfer membrane with very high protein-binding capacity) for 30 minutes to several hours, followed by agonist treatment, formalin fixation, hematoxylin staining, and immunostaining with a battery of antibodies specific for osteoblastic products. Individual cells and their secretory zones were visualized by light microscopy and counted. Treatment with PTH with or without isoproterenol resulted in increases in the percentages of osteoblastic cells elaborating cAMP, as well as the intensity of immunostaining, but had no effects on MCF-7 cells, a nonosteoblastic breast carcinoma control line. The percentage of cells within each primary osteoblastic cell population isolated or rat osteogenic sarcoma cell clone (G2 or C12) that elaborated bone-specific proteins or that generated cAMP in response to PTH varied with time and the individual cellular preparation, reconfirming the cellular heterogeneity of these systems. This method, in conjunction with techniques such as in vitro hybridization, should prove useful in characterizing discrete osteoblastic bone cell subpopulations and in clarifying mechanisms of hormonal regulation by local and systemic agents. 相似文献