全文获取类型
收费全文 | 15751篇 |
免费 | 958篇 |
国内免费 | 158篇 |
专业分类
耳鼻咽喉 | 133篇 |
儿科学 | 372篇 |
妇产科学 | 885篇 |
基础医学 | 1955篇 |
口腔科学 | 346篇 |
临床医学 | 1811篇 |
内科学 | 3350篇 |
皮肤病学 | 299篇 |
神经病学 | 1145篇 |
特种医学 | 663篇 |
外科学 | 2028篇 |
综合类 | 308篇 |
一般理论 | 8篇 |
预防医学 | 814篇 |
眼科学 | 438篇 |
药学 | 1102篇 |
中国医学 | 126篇 |
肿瘤学 | 1084篇 |
出版年
2023年 | 67篇 |
2022年 | 199篇 |
2021年 | 362篇 |
2020年 | 156篇 |
2019年 | 312篇 |
2018年 | 416篇 |
2017年 | 255篇 |
2016年 | 285篇 |
2015年 | 454篇 |
2014年 | 546篇 |
2013年 | 770篇 |
2012年 | 1107篇 |
2011年 | 1173篇 |
2010年 | 770篇 |
2009年 | 638篇 |
2008年 | 875篇 |
2007年 | 917篇 |
2006年 | 848篇 |
2005年 | 812篇 |
2004年 | 733篇 |
2003年 | 642篇 |
2002年 | 619篇 |
2001年 | 562篇 |
2000年 | 536篇 |
1999年 | 389篇 |
1998年 | 168篇 |
1997年 | 169篇 |
1996年 | 161篇 |
1995年 | 137篇 |
1994年 | 107篇 |
1993年 | 103篇 |
1992年 | 189篇 |
1991年 | 166篇 |
1990年 | 128篇 |
1989年 | 151篇 |
1988年 | 127篇 |
1987年 | 118篇 |
1986年 | 83篇 |
1985年 | 86篇 |
1984年 | 61篇 |
1983年 | 55篇 |
1982年 | 44篇 |
1981年 | 40篇 |
1980年 | 38篇 |
1979年 | 43篇 |
1978年 | 29篇 |
1977年 | 31篇 |
1976年 | 24篇 |
1975年 | 30篇 |
1973年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Feng-Chun Tsai Daniel Marelli Jessica Bresson David Gjertson Reza Kermani Abbas Ardehali Fardad Esmailian Michele Hamilton Gregg C Fonarow Jaime Moriguchi Mark Plunkett Antoine Hage Julie Tran Jon A Kobashigawa Hillel Laks 《American journal of transplantation》2002,2(6):539-545
Older age, prior transplantation, pulmonary hypertension, and mechanical support are commonly seen in current potential cardiac transplant recipients. Transplants in 436 consecutive adult patients from 1994 to 1999 were reviewed. There were 251 using standard donors in 243 patients (age range 18-69 years). To emphasize recipient risk, 185 patients who received a nonstandard donor were excluded from analysis. The indications for transplant were ischemic heart disease (n = 123, 47%), dilated cardiomyopathy (n = 82, 32%), and others (n=56, 21%). One hundred and forty-nine (57%) recipients were listed as status I; 5 and 6% were supported with an intra-aortic balloon and an assist device, respectively. The 30-d survival and survival to discharge were 94.7 and 92.7%, respectively; 1-year survival was 89.1%. Causes of early death were graft failure (n = 6), infection (n = 4), stroke (n = 4), multiorgan failure (n = 3) and rejection (n = 2). Predictors were balloon pump use alone (OR= 11.4, p =0.002), pulmonary vascular resistance > 4 Wood units (OR = 5.7, p = 0.007), pretransplant creatinine > 2.0 mg/dL (OR = 6.9, p = 0.004) and female donor (OR = 8.3, p = 0.002). Recipient age and previous surgery did not affect short-term survival. Heart transplantation in the current era consistently offers excellent early and 1-year survival for well-selected recipients receiving standard donors. Early mortality tends to reflect graft failure while hospital mortality may be more indicative of recipient selection. 相似文献
52.
Feng-Chou Tsai Ming-Huei Cheng Hung-Chi Chen Fu-Chen Wei 《Annals of plastic surgery》2002,48(1):41-47
The medialis pedis flap (MPF) has been used for the reconstruction of soft-tissue defects in the hand since 1990. From January 1997 through January 2000, 19 patients (15 male, 4 female) with hand injuries underwent microsurgical MDF reconstruction at Chang Gung Memorial Hospital. There were finger injuries in 16 patients and palm defects in 3 patients. The mean patient age was 32.6 years (age range, 16-58 years). Flap size ranged from 4.5 x 2 cm to 7 x 6 cm (mean, 6 x 2.8 cm). Only one flap had partial loss. The donor site was closed primarily in 9 patients, and was closed using a split-thickness skin graft in 9 patients and a full-thickness skin graft in 1 patient. At a mean follow-up of 13 months, the protective sensation was 16 mm using the static two-point discrimination test and was 10 mm using the moving two-point discrimination test. Based on this retrospective study the authors conclude that (1) the MPF has the advantages of thin and glabrous skin, (2) the size of pedicle is compatible with the recipient vessel in the hand, (3) there is low donor site morbidity, and (4) achieving protective sensation is possible. 相似文献
53.
54.
55.
F-J Tsai C-H Tsai S-F Wu Y-H Liu T-F Yeh 《Acta paediatrica (Oslo, Norway : 1992)》1996,85(12):1487-1490
To evaluate the catabolic effects of dexamethasone therapy on protein metabolism, amino acid concentrations and urinary 3-methylhistidine (3MH) were measured in 28 premature infants who were included in a double-blind controlled study using early dexamethasone therapy in the prevention of bronchopulmonary dysplasia. Fifteen infants received dexamethasone (0.5mg/kg/day i.v.) and 13 infants received normal saline as control. Heparinized venous blood samples for amino acid analysis were obtained before the study and again at day 5 after starting the study. Urinary 3MH was measured on days 1, 3, 5, 7, 14, 21, and 28 of treatment. A substantial increase in amino acid concentrations was observed in infants receiving dexamethasone. Alanine, glutamine, citrulline, ornithine and cystine concentrations increased twofold or more. The 3MH:creatinine ratio was increased in the treated group. These metabolic effects were most likely due to an increase in protein catabolism. 相似文献
56.
Vandellia cordifolia (COLSM) G. DON of Scrophulariaceae (V. cordifolia) is an annual wild herb indigenous to Taiwan. It can be found in plains, low altitudes, swampy places, and paddy fields. Taiwanese folk physicians use it in "nephritis, uremia, furnucle, carbuncle." The LD50 (95% confidence limit) of the crude extract of V. codifolia given by the oral route was more than 10 g/kg in rats. By the intraperitoneal route, it was 4.6 g/kg (4.35-4.93). The extraction rate was 16.6%. We studied its effects on renal functions and blood pressure and found that (1) it had diuretic effect on normal rats, (2) it decreased glomerular filtration rate and renal blood flow on normal kidneys in rabbits, (3) it had no effects on glomerular filtration rate and renal blood flow on glycerin-induced insufficient kidneys in rabbits, (4) it had diuretic effects on both normal and glycerin-induced insufficient kidneys in rabbits, (5) it could inhibit Na+ and K+ reabsorption on normal and glycerin-induced insufficient kidneys in rabbits, (6) it had hypertensive effect and this effect could be blocked by phenoxybenzamine. From the above facts, we conclude that V. cordifolia has diuretic effect and it may act on renal tubules to inhibit Na+ and K+ reabsorption. 相似文献
57.
Detection of St. Louis encephalitis virus antigen in mosquitoes by capture enzyme immunoassay. 总被引:1,自引:4,他引:1 下载免费PDF全文
T F Tsai R A Bolin M Montoya R E Bailey D B Francy M Jozan J T Roehrig 《Journal of clinical microbiology》1987,25(2):370-376
Surveillance methods that measure St. Louis encephalitis (SLE) virus activity in nature may provide forewarning of its epidemic occurrence in humans. An antigen capture enzyme immunoassay was developed to detect SLE virus in infected mosquitoes. The assay detected purified SLE viral antigen at a concentration of 62 pg/0.1 ml when antigen was incubated overnight; 250 pg/0.1 ml was detected in a single-day assay (antigen incubated for 3 h). The assay detected 67.9 and 70.8% of laboratory-prepared pools of infected mosquitoes after 3 h and overnight incubation, respectively. The sensitivity of the procedure was 90.5% in identifying pools with infectious titers greater than dex 3.0. The specificity of the assay was controlled by retesting positive pools preincubated with SLE virus and normal antibodies, which led to a diminution of signal in the pools containing viral antigen. The procedure was suitably specific in discriminating between SLE and related flaviviruses, detecting only high infectious doses of heterologous antigens. 相似文献
58.
Identification of novel steroid-response elements. 总被引:3,自引:0,他引:3
59.
Enhanced molecular volume of conservatively pegylated Hb: (SP-PEG5K)6-HbA is non-hypertensive 总被引:2,自引:0,他引:2
Acharya SA Friedman JM Manjula BN Intaglietta M Tsai AG Winslow RM Malavalli A Vandegriff K Smith PK 《Artificial cells, blood substitutes, and immobilization biotechnology》2005,33(3):239-255
Recent studies have suggested that the "pressor effect" of acellular Hb is a consequence of perturbation of the macro-and microcirculatory system in multiple ways, and that PEGylation is an effective approach for controlling the same. In an attempt to confirm this concept, a new and simple thiolation mediated, maleimide chemistry-based conservative PEGylation protocol has been developed to conjugate multiple copies of PEG-chains to Hb. This approach combines the high reactivity of maleimides towards thiols with the propensity of iminothiolane to derivatize the epsilon-amino groups of proteins into reactive thiol groups, with conservation of their positive charge. One of the PEGylated products, namely (SP-PEG5K)6-HbA, that carries on an average six copies of PEG5000 chains per Hb, is non-hypertensive in hamster top load and in rat 50% exchange transfusion models. This hexa-PEGylated-Hb has (i) a hydrodynamic volume corresponding to that of an oligomerized Hb of 256kDa, (ii) a molecular radius of approximately 6.8 nm, (iii) high oxygen affinity, (iv) lowered Bohr effect, and (v) increased viscosity and colloidal osmotic pressure. These properties of (SP-PEG5K)6-HbA are consistent with the emerging new paradigms for the design of Hb based oxygen carriers and confirm the concept that the "pressor effect" of Hb is a multifactorial event. The thiolation mediated maleimide chemistry-based PEGylation protocol described here for the generation of (SP-PEG5K)6-Hb is simple, highly efficient, and is carried out under oxy conditions. The results demonstrate that a non-hypertensive PEG-Hb can be generated by conjugation of a lower number of PEG chains than previously reported. 相似文献
60.
Improvement of Schwann cell attachment and proliferation on modified hyaluronic acid strands by polylysine 总被引:11,自引:0,他引:11
Hyaluronic acid (HyA) has the intrinsic ability to promote cell proliferation and reduce scar formation. However, the clinical use of HyA has so far been limited because of its water solubility and nonadhesive characteristics. Increasing interest in HyA as a clinically useful biomaterial has prompted our study of altering HyA's physical properties to render it a potential component of nerve grafts. In this study, strands of HyA were cross-linked by glutaraldehyde (Glut), coated with polylysine, and then inoculated with Schwann cells (SCs). Results in vivo and in vitro demonstrated that cross-linked HyA strands were water insoluble and thus less biodegradable. Poly-D-lysine-resurfaced strands showed significant SC attachment of 350-400 cells/mm(2), compared to uncoated controls (0-10 cells/mm(2), p < 0.01). Fibroblast control groups showed an attachment of 40-100 cells/mm(2) on coated strands. Immunostaining for proliferating cells showed SCs as and fibroblasts as +. Cells neither adhered to nor proliferated on the modified HyA strands that were not resurfaced. The results suggest that polylysine promotes SC attachment and proliferation to glutaraldehyde-cross-linked HyA strands, the product being a three-dimensional composite with low solubility that may have potential application in nerve grafts. 相似文献