全文获取类型
收费全文 | 13554篇 |
免费 | 687篇 |
国内免费 | 101篇 |
专业分类
耳鼻咽喉 | 79篇 |
儿科学 | 210篇 |
妇产科学 | 299篇 |
基础医学 | 1788篇 |
口腔科学 | 324篇 |
临床医学 | 833篇 |
内科学 | 3282篇 |
皮肤病学 | 384篇 |
神经病学 | 1197篇 |
特种医学 | 789篇 |
外科学 | 2348篇 |
综合类 | 33篇 |
一般理论 | 1篇 |
预防医学 | 341篇 |
眼科学 | 169篇 |
药学 | 828篇 |
中国医学 | 19篇 |
肿瘤学 | 1418篇 |
出版年
2023年 | 67篇 |
2022年 | 126篇 |
2021年 | 263篇 |
2020年 | 169篇 |
2019年 | 217篇 |
2018年 | 240篇 |
2017年 | 185篇 |
2016年 | 218篇 |
2015年 | 233篇 |
2014年 | 317篇 |
2013年 | 385篇 |
2012年 | 631篇 |
2011年 | 709篇 |
2010年 | 407篇 |
2009年 | 327篇 |
2008年 | 665篇 |
2007年 | 716篇 |
2006年 | 685篇 |
2005年 | 700篇 |
2004年 | 695篇 |
2003年 | 783篇 |
2002年 | 769篇 |
2001年 | 383篇 |
2000年 | 434篇 |
1999年 | 313篇 |
1998年 | 180篇 |
1997年 | 142篇 |
1996年 | 132篇 |
1995年 | 118篇 |
1994年 | 112篇 |
1993年 | 95篇 |
1992年 | 252篇 |
1991年 | 254篇 |
1990年 | 222篇 |
1989年 | 277篇 |
1988年 | 222篇 |
1987年 | 231篇 |
1986年 | 197篇 |
1985年 | 158篇 |
1984年 | 110篇 |
1983年 | 92篇 |
1982年 | 57篇 |
1979年 | 83篇 |
1978年 | 80篇 |
1977年 | 59篇 |
1975年 | 52篇 |
1974年 | 52篇 |
1972年 | 60篇 |
1971年 | 55篇 |
1968年 | 53篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
12.
Adriana B Campaner Alessandro Scapinelli Ruy O Machado Roberto E Dos Santos Geni W Beznos Tsutomu Aoki 《Gynecological endocrinology》2006,22(7):395-398
We report a case of a prepubertal girl with juvenile primary hypothyroidism presenting as ovarian cysts and precocious puberty. The 7-year-old female was referred to our clinic because of a pelvic/abdominal mass and vaginal bleeding. Besides these findings, on physical examination we noticed the thyroid gland globally increased and the presence of secondary sexual characteristics. Based upon the clinical profile and investigations, the patient was diagnosed with juvenile primary hypothyroidism due to autoimmune thyroiditis. The cysts and precocious puberty resolved spontaneously after the simple replacement of thyroid hormone. It is important to bear in mind hypothyroidism in cases of girls presenting ovarian cysts and precocious puberty in order to avoid unnecessary surgery on the ovaries. 相似文献
13.
Kanji Takeo Eric Virtudazo Misako Ohkusu Susumu Kawamoto Shoko Ito-Kuwa Sigeji Aoki 《Nippon Ishinkin Gakkai Zasshi》2006,47(4):257-262
In Cryptococcus neoformans the DNA content of cells having tiny buds varied rather widely, depending on growth phases and strains used. Typically, buds of C. neoformans emerged soon after initiation of DNA synthesis in the early exponential phase. However, bud emergence was delayed to G2 during transition to the stationary phase, and in the early stationary phase budding scarcely occurred, although roughly half of the cells completed DNA synthesis. The timing of budding in C. neoformans was shifted to later cell cycle points with progression of the growth phase of the culture. Similarly, a deficit in oxygen was demonstrated to delay the timing of budding, prolong the G2 phase and cause accumulation of cells after DNA synthesis, but before commitment to budding. The C. neoformans homologue of the main cell cycle control gene CDC28/Cdc2 was isolated using degenerate RT-PCR. The full-length coding region was then amplified using primers to target the regions around the start and stop codons. The gene was called CnCdk1 and was found to have high homologies to S. cerevisiae CDC28 and S. pombe cdc2. To determine its function, its ability to rescue S. cerevisiae cdc28-temperature sensitive mutants was tested. S. cerevisiae cdc28-4 and cdc28-1N strains transformed with the pYES2-CnCdk1 construct exhibited growth at the restrictive temperature. Results of the sequence analysis and the ability of CnCdk1 to complement the S. cerevisiae cdc28-ts mutations support its assumed role as the CDC28/cdc2 homologue in C. neoformans. 相似文献
14.
15.
Preoperative concurrent chemotherapy and radiation therapy followed by surgery for esophageal cancer. 总被引:1,自引:0,他引:1
Masahiko Yano Masatoshi Inoue Hitoshi Shiozaki 《Annals of thoracic and cardiovascular surgery》2002,8(3):123-130
Currently, the most promising strategy to improve the prognosis of advanced esophageal cancer is preoperative chemoradiation (CRT) followed by surgery. The superiority of CRT over radiation therapy alone has been demonstrated by several randomized studies. Many phase II studies of CRT followed by surgery have shown that the pathologic complete response (CR) rate ranges from 17 to 40%, and the median survival time (MST) is 12 to 31.3 months. Five randomized trials have compared preoperative CRT followed by surgery with surgery alone for resectable esophageal cancer, and four of them did not find any significant survival benefit for the combined treatment group. There are several issues in interpreting these findings, such as the quality of the surgery, the accuracy of the preoperative staging, the statistical power and design of the trials. Until comprehensive evaluation can be done, the standard therapy for resectable esophageal cancer should be considered to be surgery alone. The histological response in the resected specimen correlates well with the prognosis. Patients with pathologic CR display significantly better survival than those with microscopic residual cancer cells in the resected specimens. These findings suggest that more potent regimens leading to higher pathologic CR rates should improve the prognosis. Chemotherapy or radiation therapy sensitivity testing needs to be established. If accurate prediction of the response is possible prior to therapy, non-responders can be excluded. Cell cycle-related genes, apoptosis-related genes, and drug metabolizing genes have been investigated in many pilot studies and need to be evaluated by large-scale clinical studies. At present, pathologic CR can not be accurately diagnosed before surgery. Endoscopic biopsy is also unreliable for the diagnosis. In the future, new diagnostic tools such as positron emission tomography scanning, a sensitivity test or molecular markers may enable accurate diagnosis of pathologic CR to guide the choice of treatment strategies for individual patients. 相似文献
16.
17.
18.
Inhibition of PAF-induced eosinophil accumulation in pulmonary airways of guinea pigs by anti-asthma drugs 总被引:3,自引:0,他引:3
S Sanjar S Aoki K Boubekeur L Burrows I Colditz I Chapman J Morley 《Japanese journal of pharmacology》1989,51(2):167-172
Intraperitoneal (i.p.) injection of platelet activating factor (PAF) in guinea pigs caused a dose-related increase in the number of eosinophils recovered from bronchoalveolar lavage fluid (BALF). The prevalence of eosinophils in BALF had significantly increased within 1 hr of i.p. injection of PAF (10 micrograms/animal) and was maximal after 24 hr. Subcutaneous osmotic mini-pumps were used to administer drugs for 5 days prior to i.p. injection of PAF (10 micrograms/animal) and for the subsequent 24 hr. The percentage increase of eosinophils in BALF, due to PAF, was inhibited in animals treated with dexamethasone, aminophylline, cromoglycate, tranilast or ketotifen, but not in animals treated with oxatomide, azelastine, amlexanox, ibudilast or AA-861. These results suggest that inhibition of pulmonary eosinophilia may be a necessary property of prophylactic anti-asthma drugs and provide indirect evidence favoring a role for PAF in eosinophilia of asthma. 相似文献
19.
The precise course and termination levels of the corticospinal tract (CST) in the cat were studied using the anterograde transport of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP). Following injection of WGA-HRP into the pericruciate (sensorimotor) cortex on one side, we observed the precise caudal termination levels of the CST fibers in the lateral and ventral funiculi. Simultaneously, the bilateral CSTs descending through the dorsal funiculus of the spinal cord were identified. Anterogradely labeled CST fibers within the lateral and ventral funiculi were observed bilaterally to reach the level of the third sacral (S3) spinal segment, which is lower than that ever described. The lowest level of the CST fibers within the dorsal funiculus, however, reached the level of the first sacral (S1) spinal segment. In conclusion, this study demonstrates that, in the cat, there exist 6 different CSTs (crossed and uncrossed lateral, ventral, dorsal) and that the termination levels of the lateral and ventral CSTs are much lower than those described in previous reports. 相似文献
20.
Pharmacological studies suggest that beta-adrenergic receptors (beta AR) in the medial nuclei of the solitary tracts (m-NTS) facilitate presynaptic release of catecholamines and also function at postsynaptic sites. We have localized the antigenic sites for a monoclonal antibody against a peptide corresponding to amino acids 226-239 of beta AR in the m-NTS of rat brain. By light microscopy, immunoperoxidase labeling for this antibody was detected in somata and proximal processes of many small cells that were distributed throughout the rostrocaudal extent of the m-NTS. Electron microscopy confirmed the cytoplasmic localization of beta AR in perikarya and proximal dendrites of neurons. Immunoreactivity occurred as discrete patches associated with cytoplasmic surfaces of plasma membrane and with irregularly-shaped saccules with clear lumen in the immediate vicinity. Select regions of nuclear envelopes, mitochondrial membranes, and rough endoplasmic reticulum were also immunoreactive along their cytoplasmic surfaces. In contrast, the Golgi apparatus was labeled, but infrequently. Immunoreactivity was also detected at numerous post- and occasional presynaptic membrane specializations of select axodendritic junctions. Dual labeling for the beta AR-antibody by the immunoperoxidase method and for a rabbit antiserum against the catecholamine-synthesizing enzyme, tyrosine hydroxylase (TH), by the immunoautoradiographic method within the same sections, further established the precise cellular relations between beta AR and catecholaminergic neurons. Immunoreactivity for beta AR was detected in numerous perikarya and proximal dendrites that did not show detectable levels of TH. However, a few cells were dually labeled for both antigens, as seen by both light and electron microscopy. The TH-labeled terminals formed synapses at junctions both with and without beta AR-like immunoreactivity. These results from the single and dual labeling studies: (1) confirm biochemical predictions that amino acids 226-239 of beta AR protein reside intracellularly; (2) provide the first ultrastructural evidence for beta AR localization within both pre- and postsynaptic membrane specializations of a subset of catecholaminergic synapses; and (3) suggest select intracellular sites that may be involved with synthesis and/or internalization and degradation of the receptor protein. 相似文献